Analyzing Anthropocentrism Ethic A Case Study Of Climate...

Topic: analyzing anthropocentrism ethic: a case study of climate change Climate change is one of the most serious phenomenon in environment issue. As in scientist, the excess production and emission of greenhouse gases are the main cause, and the hidden executor is us, the human beings (Cook, 2010). This essay is based on the reading of â€Å"Myth as a Site of Ecocritical Inquiry: Disrupting Anthropocentrism†, but further analyze on the relationship between human and nature and critical thinking of anthropocentrism. This article will concentrate on analyzing anthropocentrism ethic by the case study of climate change, and discuss about whether anthropocentrism should be responsible for today’s ecological crisis. The sources come from a popular advertisement that created by Germaine ad agency, called â€Å"Fish†, and a report on National Geographic about the north pole ice melting issue. Also, this essay will find the connections in these two sources, associated with the anthropocentrism and further discuss about environmental ethics. The ad â€Å"Fish† was shown a fish face grew on a man’s head, the helpless eyes with the dark green background, formed a strong visual impact. At the bottom of the picture, along with the slogan Stop Climate Change Before it Changes You, called on people to take action to protect our living planet (2008). The ad lead audience to imagine that if climate change continues, global warming is exacerbated, the glaciers melting, the sea level rise caused a largeShow MoreRelatedClimate Change Essays1637 Words   |  7 Pagestemperatures, global warming is feared for its effects on climate change, such as rising sea levels and the melting of glaciers, that will ultimately result in a non-sustainable environment and negative health consequences for mankind. Life on earth depends on climate, and changes in it directly effect the health and well-being of the population, biodiversity, and the delivery of services by ecosystems around the world.(climate change climate modes) The go al of this research paper is to analyze global

Sex in The Canterbury Tales Essay - 937 Words

Geoffrey Chaucer uses sex as a manipulative instrument in The Canterbury Tales. Portraying sex as a power that women exert over men rather than the marital bond of â€Å"making love† makes evident Chaucer’s skewed views of love and marriage with underlying tones of misogyny. He expresses these views throughout the work, however, the theme of love and sex is most evident in the sub-stories of The Wife of Bath and The Miller’s Tale. Chaucer breaks the topic of sex into two basic parts: carnality and romanticism. Although carnal love is a controversial topic, Chaucer dives into the subject by creating characters with ferocious appetites for sex and the means to accommodate their desires. Whereas, to address romanticism, he relies heavily on†¦show more content†¦Her views intensify both when she states that God gave the poor the gift of sex to use as means for gaining riches and when she expresses that genitals are â€Å"wise and perfect†; they are not simply made for reproduction â€Å"they were not made for nothing, safe to say† (Chaucer). Her topic of discussion swiftly shifts off of the topic of her views on sex to the topic of a man’s roll in marriage. She begins by comparing the wife to a debtor and the husband her slave, then stating that she will have unlimited power over his body during their marriage. The wife continues on with details of her five marriages to say that she previously had three unfit husbands and two fit husbands. Focusing less time telling about the unfit, she simply focuses her tale to tell of how she believes one should go about marriage- much like a business transaction. â€Å"By accepting the reduction of female sexuality to an instrument of manipulation, control and punishment† the wife gets what she wants through withholding sex. (Aers 148). The wife’s character in The Wife of Bath ultimately argues for Chaucer’s skewed representation of love, sex and marriage as seen in the Canterbury Tales. The manifestation of Chaucer’s perceptions lie in the actual tale as well as the prologue of The Wife of Bath when power is no more than momentarily relinquished to a man non-consensually through rape. Power is hastily regained by women when the rapist’s fate is putShow MoreRelated Character Analysis of The Wife of Bath of Chaucers Canterbury Tales1623 Words   |  7 Pages Character Analysis of The Wife of Bath of Chaucers Canterbury Tales The Canterbury Tales is Geoffrey Chaucers greatest and most memorable work. In The Canterbury Tales, Chaucer uses a fictitious pilgrimage [to Canterbury] as a framing device for a number of stories (Norton 79). In The General Prologue of The Canterbury Tales, Chaucer describes in detail the pilgrims he meets in the inn on their way to Canterbury. Chaucer is the author, but also a character and the narrator, and acts likeRead MoreGeoffrey Chaucer s Impact On Literature1231 Words   |  5 PagesWestminster Abbey’s Poet’s Corner. In Chaucer’s life he wrote over 500 works of literature, which includes The Book of the Duchess, The House of Fame, The Legend of Good Women and Troilus and Criseyde. Chaucer’s best known work is The Canterbury Tales. The Canterbury Tales was highly influential on how different social classes were viewed back in the 1300’s. He is also known for his original style of writing that developed the vernacular of middle English. Chaucer has very clearly influenced and inspiredRead MoreThe Canterbury Tales by Geoffrey Chaucer Essay1115 Words   |  5 Pages The Canterbury Tales is a set of stories written by Geoffrey Chaucer in the fourteenth century. The stories were told by a group of pilgrims traveling to Canterbury Cathedral, in hopes to see a shrine of Saint Thomas Becket. To make time go by the host recommended each pilgrim tell a tale. The tale that each character gives, reveals that person’s background and life. Some pilgrims matched their stereotype of that time but most do not. The Prioress, Madame Eglentyne, and Wife of Bath, Allison, areRead More Summary and Analysis of The Shipmans Tale (The Canterbury Tales)928 Words   |  4 PagesSummary and Analysis of The Shipmans Tale (The Canterbury Tales) Introduction to the Shipmans Tale: The Host asks the priest to tell a tale, but the Shipman interrupts, insisting that he will tell the next tale. He says that he will not tell a tale of physics or law or philosophy, but rather a more modest story. The Shipmans Tale: A merchant at St. Denis foolishly took a desirable woman for a wife who drained his income by demanding clothes and other fine array to make her appearRead MoreHypocrisy In Canterbury Tales Essay807 Words   |  4 Pagesliterature works of Canterbury Tales, Lysistrata and Vindication, we view the negativity of the townspeople because of hypocrisy of the highest power. In Canterbury Tales there is hypocrisy in the church due to the pardoner, in Lysistrata, women are not granted rights, and in Vindication, women were not allowed to education. In Canterbury Tales, the pardoner vouches for the pardoning of those who come to the church to confess their sins. Specifically in the Pardoner’s Tale, we see how he preachesRead More Chaucers Canterbury Tales Essay - The Powerful Wife of Bath1099 Words   |  5 PagesThe Powerful Wife of Bath   Ã‚  Ã‚  Ã‚  Ã‚   In Geoffrey Chacers The Canterbury Tales we are introduced to 29 people who are going on a pilgrimage to St. Thomas a Becket in Canterbury. Each person is represented to fit a unique type of behavior as shown by people during the medieval ages.   My attention was drawn to the Wife of Bath through which Chaucer notes the gender inequalities.   Predominantly, women could either choose to marry and become a childbearing wife or go intoRead MoreThe Canterbury Tales, by Geoffrey Chaucer1582 Words   |  7 Pages Geoffrey Chaucer wrote the Canterbury tales a collection of short tales in the 14th century. The compilation of stories are told by different characters within the narrative as part of a game proposed by the host. Each individual must tell two stories on their journey and two stories on their way back. Each story tells some aspects of English life during the time and often added satire like qualities to the English life. In particular Chaucer often tells stories with elements of the relationshipRead MoreEssay Immorality in Chaucers Canterbury Tales1646 Words   |  7 PagesChaucer’s The Canterbury Tales, he specifically illustrates through his pilgrims’ stories some comical and realistic events that display immorality in the Middle Ages. There are several characters whose stories are focused on presenting the immorality within their tales. Like that of â€Å"The Miller’s Tale,† and â€Å"The Merchant’s Tale.† Chaucer utilizes these tales to display one specific immoral act, which is sexual sin or lust. Chaucer addresses the seven deadly sins in his novel; The Canterbury Tales, lustRead MoreLady of Bath vs. Desdemona1394 Words   |  6 Pagesof Bath’s Prologue in Geoffrey Chaucer’s The Canterbury Tales seemingly go against common conventions of women, as they are bold characters who have strong opinions and exert dominance. Dame Alison, the Wife of Bath, is a character created by Chaucer in The Canterbury Tales. She is a merchant who has an interest in profit, and uses sex and her many husbands to gain that profit. Alison has been married five times, and she is open to more, as sex is extremely important to her. â€Å"Welcome the sixteRead MoreChildrens Versions of The Cantebury Tales1465 Words   |  6 PagesBeing a work filled with an unprecedented â€Å"wealth of fascinating characters†, Chaucer’s The Canterbury Tales has been translated and retold in many versions over the years (Cohen 7-8). Unavoidably translations and retelling require choices made by writers and editors of how to represent things and what to include, which can easily change aspects of the original story. The most difficult retellings may be versions written for children as writers not only have to deal with modernizing the language

Marginal Revenue and Profit Free Essays

?In order for a company to be able to reach its full potential financial management must be in place. This management needs to be aware of at least the basics of financial plans which are revenue, cost and profit. These three things can make or break a company. We will write a custom essay sample on Marginal Revenue and Profit or any similar topic only for you Order Now Each of these things must be understood and considered before plans can be laid to create or better a company. Revenue is the amount a company receives (Marginal Revenue, 2009). If a company is in the business of sales, revenue is the amount of money the company receives per unit sold. Marginal revenue is the amount of money a company receives for the last unit sold. This is found by dividing the change in revenue by the change in quantity sold. For companies that compete with one another marginal revenue is not very important. This is because in a competitive environment most products are sold at a set price so that marginal revenue is equal to the set sales price of the product. For a monopoly on the other hand, marginal revenue is very important. Monopolies have a decreasing marginal revenue curve (marginal Revenue, 2009); for a monopoly the marginal revenue is less than the sales price. This is because a monopoly must have a lower sales price in order to increase the amount of product sold. Total cost is the amount of money it costs to operate at a particular rate of production (Baker, 2000). There are two types of cost: variable and fixed. Fixed costs are those that remain the same regardless of production and variable costs are those that change with production. Marginal cost is the addition either to total cost or total variable cost resulting from one more unit of output (McConnall Brue, 2008). Usually this is found by dividing the change in total cost by the change in quantity. Profit is the positive gain from an investment or business operation after subtracting expenses (Profit, 2009). Profit maximization is the idea that people will try to create as high a profit as possible given the circumstances. Since marginal revenue is the amount of revenue an additional unit will bring in and marginal cost is the amount the additional unit will cost to produce, then profit maximization is the point where marginal cost and marginal revenue are equal (Profit Maximization, 2009). So as long as marginal cost is lower than marginal revenue there is profit, but if marginal cost ever exceeds marginal revenue the last unit should not be produced. If the marginal revenue is higher than the marginal cost, the company can produce more units. Business owners and managers need to be able to make a profit. Whenever people think of profit, they are aware that profit is the amount of money left after the expenses are paid and most people know the greater the profit the better off they will be. Most people do not know that profit maximization requires the knowledge of marginal cost and marginal revenue. In order to determine when a company is no longer profiting from production of extra units, one must know that profit maximization is the point where marginal revenue equals marginal cost. Refernces (2009). Marginal revenue: Fundamental finance. Retrieved July 16, 2009, from fundamentalfinance. com Web site: http://economics. fundamentalfinance. com/micro_revenue. php Baker, S. (2000). Cost concepts. Retrieved July 16, 2009, from Economics interactive tutorial Web site: http://hspm. sph. sc. edu/COURSES/ECON/Cost/Cost. html (2009). Profit. Retrieved July 16, 2009, from investorwords. com Web site: http://www. investorwords. com/3880/profit. html Profit Maximization. Retrieved July 16, 2009, Web site: http://www. econ. ilstu. edu/ntskaggs/eco105/readings/profit-max. htm McConnell, C. , Brue, S. (2008). Microeconomics 17th ed. New York: McGraw-Hill Irwin. How to cite Marginal Revenue and Profit, Papers

Develop & Use Of Emotional Intelligence â€Myassignmenthelp.Com

Question: Describe about the Develop and Use Emotional Intelligence. Answer: Introduction The study is focussing on the behaviour of Store Managers of Australian Hardware in Wollongong about the performances of the stores. The Australian Hardware is a hardware and home ware retailer that has expanded their business almost all over the country in Australia in 140 stores (Ciarrochi Mayer, 2013). The researcher is then analysing various situations that the organisation has faced in the last few time. The evaluation of the financial performance of previous year, misbehaviour of employee, annoying situation etc in the company has enabled the researcher to explain the emotional sides of the manager in leading the organisation. Therefore, the researcher has discussed the appropriate leadership style for the manager in the store and discussed the desired behavioural aspect for the hardware company. 1. In this case, the Store Manager has created a mess in the Store of Wollongong that has forced the department managers to take the decision to lave the organization. Otherwise, they started creating a massive pressure on the sales staffs of the store to increase their revenue knowing that it is not possible for the sale staff too. In this situation as the General Operations Manager, the researcher should apply the positive leadership behaviour to overcome the situation. Therefore, the researcher would motivate the Store manager to learn the process of positive leadership style and try to minimise the embarrassments of the lower staffs rather insulting them in front of all whether there is no fault from their side. The researcher has also suggested the Store Manager, who has created the worse situation with wrong decision, to show the respect and dignified behaviour in this type of situation later. The Store Manager has analysed that the Store manger lacks the emotional intelligence that is required for become a good manager. Therefore, as the General Operations Manager the researcher is suggesting the Store Manger to acquire three main emotional intelligences such as, attunement, empathic accuracy and looping (Baron et al. 2013). These three concepts will enable the Store Manager to become a good manager with the ability to understand others feelings and emotions. The empathic accuracy will enable the manager to understand the degree of accuracy while noticing others emotions and creating a loop of emotional feedbacks through verbal or non-verbal signals also helps her to understand the staffs emotional conditions (Mortiboys, 2013). If the Store Manager can follow this, then this will be reflected in her behaviours. In the situation if the Store Manager has retaliate in an appropriate manner then the situation should not lead to thus much worst. Therefore, as per the researcher, the Store Manager could have reacted in a different manner and in the meeting; she could discuss the situation to identify the reasons for which the company has faced the low revenue. After the discussion, they could find out the actual issue regarding the problem and then she could suggest the way to overcome the situation not to face problems in future. However, in contrast she has yelled on the department managers who were not attached with the problem and created a mess in the organisation. The store manager has reacted in a manner that was against the store morale. According to the store, morale the Managers has to behave in a manner that should not affect any employee of the store. Nevertheless, the process in which the Store Manager has reacted after the situation was completely against the store morale as the reaction of her has influenced the Department Managers to take negative decisions, which was not appropriate for the store. In this case, the unpleasant behaviour of the Store Manager has influenced the department managers to take the decision of leaving the store due to getting the disrespectful behaviour and over pressure of work. Apart from this, the sales staffs of the stores too leaving the job as some department managers has created massive pressure on them to increase the sales revenue. 2. In this case, one of the staff from the sales team has complained about a team member that she is not participating in the team activities that other team members take part. The main complain was about the nature of the team member who was not participating in the regular activities of the group. As the other members always discuss about the normal day to day conversations regarding family, friends, movies, cultures, religious things etc in which that team member not involve herself (Laschinger et al. 2014). For this problem, the team members can misinterpret her activities in other way. For instance, if the team members are planning for any party then she cannot participate in the party, as she likes to remain aloof from the others. However, by nature, she cannot adjust herself with the late night parties; alcohol etc as she has came from another religious background but the team members misinterpret this in a way that she is not interested to become familiar with them. Apart fro m this, while working as a team the members cannot relate with her, as she is not friendly with them therefore she is misinterpreted, as she is unfriendly. In this case as the Operational Manager the researcher has faced a problem regarding the issue of an aloof team member who was not participating in the regular activities of the team. This became an issue for the other team members among them one has came to complain the manager. The researcher can explain the matter to that team member as the cultural diversity, which is a very common thing in the workplaces (Vella, Oades Crowe, 2013). The researcher will make the team member understand that the cultural diversity is a differentiation that makes the difference between the people working in same place. Therefore, the cultures and systems differ as per the background of each worker. This is not be misinterpreted by the other team members if she is not able to mix up with them, they do not complain against them rather they should help her to become familiar with them for the benefit of the team. The process of increasing knowledge about each others cultures and rituals will diminish this cultural diversity. If the team members can gain the knowledge of the religious cultures and they can understand each others cultures then the knowledge will help the team members to become familiar with each other easily and the diversity problem will never be highlighted in the workplace of the store. 3. In this situation, the researcher is fighting with the emotions of his or her inner self, regarding an employee. The researcher is trying to train one employee by implementing a training session in which the teamwork capability will be increased (Robbins et al. 2013). In this process, one of the employees is creating problem by not attending the training sessions intentionally. This behaviour of the employee is making the manager very angry. However, the employee does not do any work wrong that the manager can blame him for his faults. This creates a very huge conflict in the mind of the Manager regarding this particular employee whom he or she cannot control or manage according to his or her interest. The manager should not express this anger before the employee but he or she has to control the anger. The manager has understood that he or she cannot manage the employee with providing stricter rules and regulations rather they should be managed with their own thoughts (Kelloway et al. 2013). Therefore, the manager should learn the processes to interact more with the employees to understand their feelings and emotions that will enable him or her to develop the team more efficient. The manager can improve the emotional and intelligence power by teach the employees personally as much as possible (Ealias George, 2012). If the manager can learn the personalities of every employee then he or she can relate and use them in the workplace to reduce the problem regarding employee issues. In this context, the manager should learn about the three elements to relate with the employees. The three main elements are making relationship with the employees, building a proper leadership style to lead the employees properly and developing a goof communication skill with the employees (Doe, Ndinguri Phipps, 2015). These learning can help the manager to understand the employees aspect of thinking regarding the decisions of the management for any particular event. For instance, in this case the manager has arranged some training sessions to improve the teamwork capability of the employees as he or she has noticed a few problems regarding the team members while working with each o ther. However, it was implemented for the betterment of the employees still on employee among them did not attend the training session intentionally. This has led the manager to become angry on the employee but still the manager cannot express his or her anger on the employee. The manager here increased the awareness of the employees to increase the capabilities of the employees to work smoothly in a team. As a general operations manager, the researcher has to improve the emotional intelligence to reduce the anger and annoying situations, required to meet the target performance level by any means and for this, the learning of the employees will enable him or her to act well in his or her position (Podsiadlowski et al. 2013). The learning also will help the employees to manage their emotions and understand the decisions of the management that they can co-operate with them. 4. In this case, the company has implemented some new policies and decision-makings that will increase the revenue of the Wollongong Store, which has faced low revenue in the section of Timber and Plumbing and Electrical departments (Harvey Allard, 2015). Therefore, the management of the company has taken the decision of reducing the cost consuming projects such as trainings, which were conducted to increase the knowledge of the employees etc and boosted the projects that increase the revenue of the store. This sudden change has made the employees emotionally affected, as they were not used to work in such load. The management can implement the changes in an employee friendly way then; the process will not affect the employees negatively. The management was not wrong in their decision-making process and they need to reduce the projects those are consuming costs in the time as the company was going through small revenue (Hor, 2012). However, the decision-making was relevant to the situation but the process of decision-making was not correct. In the case, the management could have taken the decisions of reducing the costs by delaying the training sessions or by implementing new plans and programs for increasing the revenue. Therefore, the process of decision-making can be more suitable for the employees to accept and to work with the new process rather the process has became very unhealthy for them to execute (Robinson Francis, 2014). The management of the Wollongong Store has to maintain the laws and legislations regarding the health and safety of the employees. The new work rules that the company was implementing were must follow the rules and regulation of the Australian government. According to the laws of Health and Safety Act, every company needs to take care of the employees health and safety (Vella, Oades Crowe, 2013). In this case, as the company was suddenly giving a high pressure on the employees, which was creating a massive pressure on the health and in this way their safety was too affecting. Conclusion On concluding the study, the researcher has evaluated various situations of the Wollongong store of Australian Hardware where the Store Manager has created a blunder by her decision that has affected the employees of the store in their working. The Store Manager has yelled on the department managers that they had not served their responsibilities properly and for that reason, they have to face the low revenue. However, the manager can retaliated in more positive leadership style to solve the problem rather creating another problem. The researcher has also observed that the practice of appropriate emotional intelligence should allow the managers to manage any negative situations. Reference List Baron-Cohen, S., Lombardo, M., Tager-Flusberg, H., Cohen, D. (Eds.). (2013).Understanding Other Minds: Perspectives from developmental social neuroscience. OUP Oxford. Ciarrochi, J., Mayer, J. D. (2013).Applying emotional intelligence: A practitioner's guide. Psychology Press. Doe, R., Ndinguri, E., Phipps, S. T. (2015). Emotional Intelligence: The Link to Success and Failure of Leadership.Academy of Educational Leadership Journal,19(3), 105. Ealias, A., George, J. (2012). Emotional intelligence and job satisfaction: a correlational study.Research journal of commerce and behavioral science,1(4). Harvey, C. P., Allard, M. (2015).Understanding and managing diversity. Pearson. Hor, J. (2012).Managing Workplace Behaviour: A Best Practice Guide. CCH Australia Limited. Kelloway, E. K., Weigand, H., McKee, M. C., Das, H. (2013). Positive leadership and employee well-being.Journal of Leadership Organizational Studies,20(1), 107-117. Laschinger, H. K. S., Wong, C. A., Cummings, G. G., Grau, A. L. (2014). Resonant leadership and workplace empowerment: The value of positive organizational cultures in reducing workplace incivility.Nursing economics,32(1), 5. Mortiboys, A. (2013).Teaching with emotional intelligence: A step-by-step guide for higher and further education professionals. Routledge. Podsiadlowski, A., Grschke, D., Kogler, M., Springer, C., van der Zee, K. (2013). Managing a culturally diverse workforce: Diversity perspectives in organizations.International Journal of Intercultural Relations,37(2), 159-175. Robbins, S., Judge, T. A., Millett, B., Boyle, M. (2013).Organisational behaviour. Pearson Higher Education AU. Robinson, R., Francis, G. (2014). SFAIRP vs ALARP. Vella, S. A., Oades, L. G., Crowe, T. P. (2013). The relationship between coach leadership, the coachathlete relationship, team success, and the positive developmental experiences of adolescent soccer players.Physical education and sport pedagogy,18(5), 549-561.

Second Great Awakening Essay Example

Second Great Awakening Essay The Second Great Awakening was an enormous religious revival that swept the American nation in the beginning of the 19th century. A revival is defined by Webster Dictionary as the growth of something or an increase in the activity of some hint after a long period of no growth or activity. This revival caused an unfathomable amount of permanent change to the United States. The Second Great Awakening converted millions of Americans, resulted in several new denominations of faith, changed the the way the Name Rican people viewed religion, caused a long period of reform, and connected democracy an d religion. Between years 1765 and 181 5, an era called the American Enlightenment me phased reason, education, liberty, and tolerance over any divine power. This Enlighten moment, or Age of Reason, brought the New World ideas from the Old World, such as John Locke s social contract theory, ideas concerning democracy and liberty, and a vision of a stir Eng government that protected its citizens; these radical new political ideas rejected monarchy and ultimately caused the American Revolution in 1776. The American Enlightenment also re evolved around human control rather than spiritual control. For example Deism, a philosophy hat God created the universe with set natural laws and then left it completely in humanity co intro, began to grow in the U. S. This caused the new nation to drift from religion. However, in the 1 asss The Second Great Awakening ignited in Connecticut in order to counter the domino once of reason by emphasizing the importance of religion. The revival began with Congregation annalists (Puritan descendants), Anglicans (Episcopalian), and Quakers. Revivals were dominate deed by the educated, such as Yale president Timothy Dwight. We will write a custom essay sample on Second Great Awakening specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Second Great Awakening specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Second Great Awakening specifically for you FOR ONLY $16.38 $13.9/page Hire Writer As the revival continued to counter the American Age of Reason, it spread to the frontier. When it arrived in states us chi as Tennessee and Kentucky, it quickly evolved into a much different movement. The most successful revivalists ceased to be educated intellectuals and scholars, rather normal farmers, artisans, etc. Who had been converted themselves, such as the Eocene trick Lorenz DOD. The revival began to give way to camp meetings. These meetings were h age prolonged gatherings of hundreds of members of several denominations. Some meeting s had attendance that reached five figures such as the popular camp meeting that o occurred in Cane Ridge, Kentucky, which reached 20,000. The meetings were conducted in pope air camps and could last days. People were housed in tents and heated with campfires. Crowds sang, shouted, praised God, and listened to revivalists proclaim that the Second Co mining of Jesus was approaching and society must be improved immediately. The meetings e encouraged moral and social order that discouraged inappropriate behavior. Sometimes strange conversion activities would occur such as men and women barking like a dog, rolling around, and contorting their bodies. Critics of the revivals attacked the meetings for a advocating desire. Also preaching the gospel in the West were missionary groups such as the American Home Missionary Society, created in 1826. Many denominations grew as a result oft he revivalists, especially Baptists and Methodists. Methodists were undoubtedly the most successful religion Of the Second Great Awakening concerning sheer numbers and popularity. In 1800, Methodists possessed around 70,000 members, and in 1844 over 1 T his is partly due to the utilization of circuit riders, such as Peter Cartridge, who preached of benevolence to all who would listen . Circuit riders were young men that rode around the n action spoke the word of the Methodist church. Another reason for Methodist success, was the r appeal to the common man. Methodists emphasized the importance of emotion over Intel genre, moral order, and a strong work ethic, which beguiled the common man with little e education. The result of the growing Methodist church was a revival that was very emotional and encouraged social activism. Due to the immense success of the revival in the frontier it WA s inevitable that it would soon diffuse eastward. 2 This inevitable advance occurred in the sass in western New York. The area where revival was most popular was nicknamed Vote Overburden District. This regime on was situated ear the new Erie Canal, which had attracted numerous people in search of w lath. This area was additionally home to many Americans Of Puritan descent. A man by the n name of Charles G. Finned, better known as the father of modern revivalism, quit his studies to become a lawyer in 1821 after he underwent a religious conversion. He then became a Presbyterian minister and began preaching along the new canal, New York City, and Boost n. Finned used new techniques to increase the rate of conversions. Such techniques include t he anxious seat and the protracted meeting. These techniques were put into place at t e citywide revival of the canal city Rochester in 1 83031. This revival was Fineness largest, and was a primary source of his reputation. Adding to Fineness reputation was the coop aeration among different denominations during his revivals. Fineness utilization of the above d extinguish him from other revivalists of his time, and those of the First Great Awakening beef re him. Also distinguishing Finned from First Great Awakening revivalists such as Jonathan Edwards was his view on revivals and sin. Finned believed revivals were human creation who areas Edwards would argue they were Gods creations. Furthermore, Finned believed human s chose to sin and had the power to . He also rejected the Calvinist idea that God chooses who may enter heaven. Fineness ideas were labeled as evangelical Protestantism. S denomination focused on emotional conversions and the idea that humans a re in control of their own destinies. This appealed to most Americans because this was the ere a of the factory worker. Factory workers had miniscule control over the economy or the direct ion of their lives so Fineness promise of control that came with the Second Great Awakening en courage them to participate in the revival. US citizens wanted to hear that they were in count roll and could make anything of themselves. The last thing that set Finned apart from other revivalists was 3 his use of women. This contributed to his success because women outnumber red men 2 to 1. Finned often used mens daughters and wives to convert them. For example, a wife of a Rochester physician by the name of Melanie Smith, was converted and convince cede her religiously inactive husband to join a Presbyterian church. The American nation n had exploded with religious activism. Despite the popularity Of the overwhelmingly protestant Second Great Awake inning, it drew many critics. Many critics disliked the lack of tradition and sheer amount of change that emerged from the revivals. One group of critics called the Unitarians believed that Jesus was not the son of God, but a perfect, yet human, role model that man should stir eve to imitate. Unitarians, such as Unitarian leader William Chancing rejected the emotional encouragement of the Second Great Awakening and instead endorsed knowledge. Unitarians believed that character should be built over time and could not be received in a camp meet inning over the course of a few days or less. The critics were also composed of mainly wealth y and educated citizens, which sharply contrasted the typical convert in the Second Great Away kenning revivals. Unitarians did however share the belief with the revivalists that society can be perfected by the hands of humanity. In addition to critics, the Second Great Awakening pro educed Utopia communities due to the spirit of perfectionism. Utopian communities separate deed from society and attempted to create a perfect community. One of the most famous and s successful Utopian communities was the Shaker community. Founded by English Mother Ann Lee, the Shakers believed in close knit communities, a good work ethic, and celibacy. To expel temptations of sexual relations, Shakers Often danced, hence their name. At t heir peak, they had over 6,000 members. Another new religion resulting from the Second Greg at Awakening was the Church of Latterly Saints or Morons. Joseph Smith founded the re logion in 1827, in New York. The Book of Mormon states Jesus actually arrived in the New Woo RL and was 4 forgotten by the time Columbus arrived. These radical ideas caused the Peres auction of Morons and eventually led to their journey west to Utah, where they could e free of persecution. Today, the Mormon faith continues to grow. Despite the imports once of these new religions, this was only one outcome of the Second Great Awakening. Other effects of the the Second Great Awakening were vast and permanent. R elisions participation grew as shown by the Methodists increase in number by 15 fold, the 20,000 member attendance at Cane Ridge and the 12,000 baptized solely by Peter Ca airtight. God and religion became a bigger part of the common mans life. The Second Great t Awakening revolutionized the way the gospel was preached. Before the revivals, settled ministers in fixed arises was the standard of religion in America. After the revivals, people tray veiled place to place searching for people to preach to. The revivals resulted in several new d nominations, such as the Morons and the Shakers. The Second Great Awakening was also a significant cause of the Antebellum Reform, the period of social change that occurred thro ought the 19th century. The Second Great Awakening not only directly preached the neck assist of moral and social order, but also stated that the power of change is In humanity ha ends and it is humanity obligation to try and spiritually and morally perfect society. Men a ND women alike used religion to justify change to better their society. Complementing the Sec nod Great Awakening in its endeavor towards reform was a philosophy called Transcend mentalist. Transcendentalists, led by Ralph Wald Emerson, stated all humans were boor n good and all wrong stemmed from society. This philosophy encouraged people that they c loud perfect the world by perfecting society. Together, the Second Great Awakening and Trans sentimentalism initiated reform in the 19th century. For example, the war on liquor, known by many as the temperance movement, ensued in the 1 sass. In the movements beginning, re formers only spoke of moderation. At the time, annual alcohol consumption was relatively high; in 1825 it was a staggering 7 gallons for an adult male, which is three and a half times g rater than todays consumption. In 1825 Lyman Beechen abandoned moderation and De announced all use of alcohol beverages. In 1 826 the American Temperance Society was created. This was a group that completely rejected the use of alcohol and in 1834 5000 other socio ties supported them. Temperance leaders stated drunkenness was a sin and God disapprove d of the amazing evil. In order to support their cause, temperance revivalists spoke o f the sinfulness of domestic violence induced by alcohol. The religious revival also gave people e the confidence to change the sobriety of their society. The temperance movement t had great success. By 1840, alcohol consumption had dropped to less than half. Maine prohibited the manufacture and sale of alcohol in 1 851 and factories in Massachusetts stoop deed selling liquor to workers. This reform set the foundation for the Prohibition Era in 1 920, hi chi links the Second Great Awakening and the national ban on alcohol in the 20th century. Another reform resulting from the Second Great Awakening is abolition. Inspired by the feeling g control over society and the moral obligation encouraged by the Second Great Awakening men such as the white radical William Lloyd Garrison took a stand against slavery. Garrison viewed slavery as morally outrageous, even satanic. He once burned a copy of the U. S. Consist tuition saying it was a pact with the devil. Abolitionists used similar tactics as revivalists in the e Second Great Awakening such as large public speeches or pamphleteer, in order to con next religion and abolition. With this connection, abolitionists conveyed the idea that slavery w as a sin. After undergoing a massive religious revival, America depended more heavily on reel going, therefore the message hit home on many Americans. However, not all Protestant reform mere supported the abolition cause; Beechen himself attempted to suppress abolition activity i n 1 834 as the Cincinnati Lane Theological Seminary president As more and more northern earners supported the emancipation of all slaves, tension between the North and South grew ova ere the touchy 6 subject. By 1 843, 100,000 northerners were part of the American Antislavery Society. These tensions ultimately led to the civil war between the halves of the U. S. , hi chi connects the Second Great Awakening to the American Civil War. The final main reform ins paired by the Second Great Awakening was the Womens Rights movement. Womens paretic pupation in the revivals and the previously discussed reforms, eventually led to a reform Of the Eire own. During the Second Great Awakening women participation outnumbered mens two t o one. Finned and other revivalists spoke of empowerment and how one was in control of t heir own body and destiny. Women as a result were encouraged to participate in society. HTH is also the result of the social activism the Second Great Awakening caused. Both the Am Rican Temperance Society, one third to one half women, and the American Initials ere Society utilized substantial women participation. Women such as Angelina and Sarah Grime lectured men and women alike all over New England about the abolition cause in 1 837 , and when they were criticized for their gender, they responded by creating two essential word KS of feminism. These works were to explain the sisters desire for equal rights and are called Letters on the Condition of Women and the Equality of the Sexes and Letters to Catherine E. Beechen. Women became to become increasingly discontent lack of rights despite their participation in their community, encouraged by the Second Great Awakening, This movement t resulted in the Seneca Falls Convention, the first convention held concerning womens rights, in New York and set the quest for woman suffrage that lasted until 1 920 when the goal WA s accomplished. Women owe much of their success to the Second Great Awakening. On a political subject, the Second Great Awakening furthered Americas soups art Of Democracy. Since Finned repetitively and definitively established that humanity y is in control of he world and not a divine power.

Rene Descrates essays

Rene Descrates essays While the great philosophical distinction between mind and body in western thought can be traced to the Greeks, it is to the seminal work of Ren Descartes (1596-1650) [see figure 1], French mathematician, philosopher, and physiologist, that we owe the first systematic account of the mind/body relationship. Descartes was born in Touraine, in the small town of La Haye and educated from the age of eight at the Jesuit college of La Flche. At La Flche, Descartes formed the habit of spending the morning in bed, engaged in systematic meditation. During his meditations, he was struck by the sharp contrast between the certainty of mathematics and the controversial nature of philosophy, and came to believe that the sciences could be made to yield results as certain as those of mathematics. From 1612, when he left La Flche, until 1628, when he settled in Holland, Descartes spent much of his time in travel, contemplation, and correspondence. From 1628 until his ill-fated trip to Sweden in 1649 he remained for the most part in Holland, and it was during this period that he composed a series of works that set the agenda for all later students of mind and body. The first of these works, De homine [1] was completed in Holland about 1633, on the eve of the condemnation of Galileo. When Descartes' friend and frequent correspondent, Marin Mersenne, wrote to him of Galileo's fate at the hands of the Inquisition, Descartes immediately suppressed his own treatise. As a result, the world's first extended essay on physiological psychology was published only well after its author's death. The year 1641 saw the appearance of Descartes' Meditationes de prima philosophia, in quibus Dei existentia, corpore distinctio, demonstratur In 1649, on the eve of his departure for Stockholm to take up residence as instructor to Queen Christina of Sweden, Descartes sent the manuscript of the last of his grea ...

Human Resources for Industry Essay Example | Topics and Well Written Essays - 2250 words

Human Resources for Industry - Essay Example Moreover, it has become a more complicated task to find and utilise workforce for highly specialised positions. Thus, there is more importance of human resource management in organisations than ever before. This paper will try to analyse the importance of HR management, the present day challenges faced by HR management in common, the different ways the HR managements usually adopt to cope up with the changes, the changing nature of workplace, and some modern studies into HR management. The Role and Importance of HR management One can undoubtedly say that the role of HR has increased tremendously in all organisations. The role of Human Resource Management in the 21st century starts from the board room to the market place. The challenges before HR managers in the twenty-first century, according to Bohlander and Snell (2007, p.5) are going global, embracing new technology, managing change, managing talent or human capital, responding to the market, and containing costs. In recent years, more attention is paid to how the human resource management affects organisation’s overall performance than to what practices are adopted in human resource management. ... For example, the Vodafone Company, started in England in 1982 has now operations in Europe, Asia-Pacific, Middle East, Africa, and the Americas. In addition, the GlaxoSmithKline has its origin and headquarters in UK, Consumer Products headquarters in Pennsylvania, and major centre for biopharmaceutical products in Germany, Canada, and USA. It sometimes becomes necessary to assess the skill of a foreign workforce, translation of some materials into regional languages, training for foreign workforce, and many a time, deciding the compensation for foreign employees. The onslaught of new technology The advent of technology made it possible for organisations to store, retrieve and analyse data easily. As a result, the nature of the workplace changed a lot. Instead of the large number of workforce of the past that required only little knowledge, today, the job positions require considerable amount of skill and the present jobs involve a lot of planning, decision making and problem solving. In addition, the present workplace more often requires retraining of employees when they are displaced. Human Resource Management too has changed considerably through the use of technology. The first and foremost development is the adoption of human resources information system (HRIS), thus making response times, decision making, and customer service faster and easier. In UK, the National Health Service has started implementing the Electronic Staff Record, a national, fully integrated payroll system. Many other UK firms too have same form of HRIS in use. The first advantage of this system is greater efficiency and reduced cost. For example, Cisco Systems have developed an intranet system which helps them save about

The story of an hour by Kate Chopin Research Paper

The story of an hour by Kate Chopin - Research Paper Example mmediate duty to grieve over her husband’s death as depicted in the line â€Å"She wept at once, with sudden, wild abandonment, in her sister’s arms.† Mrs. Mallard, however, escapes the face of agony right away upon entry to her room, as though it were a private world of all unseen hopes. Apparently, the room represents another dimension consisting of objects that symbolize what Mrs. Mallard has long yearned for and Chopin illustrates this in the phrases â€Å"new spring life†, â€Å"delicious breath of rain†, and â€Å"countless sparrows† twittering. While part of her consciousness has fully absorbed the thought that she is expected to mourn for a major loss, she is being spontaneously consumed by something that makes her exclaim â€Å"free, free, free!† and â€Å"Free! Body and soul free!† in a rather cautious mumbling gesture which is altogether understood by herself alone. In that realm, the moment of illumination leads the widow to cherish mixed conflicting emotions where she obtains a sense of certainty toward a much desired fate – the return to singlehood and freedom. Chopin proceeds to enumerate the attributes that recollect the state of youth of Mrs. Mallard, stating â€Å"She was young with a fair, calm face, whose lines bespoke repression and even a certain strength.† These details may be claimed as necessary in order for the character of Louise to emerge out of Mrs. Mallard and exhibit some sharper manifestation of hope for liberation despite lack of concrete evidences to support the idea that the passing away of Brently amounts to the happiness of Louise. This hope eventually shatters when Mr. Mallard comes back alive, contrary to the previous belief, so that his presence causes the irony of his wife’s diagnosis where â€Å"the joy that kills† is actually a metaphor that means â€Å"the joy that has been killed.† Women of the 1800s lived in societies that were sexist by nature. Most opportunities in and out of an industry employed men for a variety of

Sushi Digesting Genes Article Review Example | Topics and Well Written Essays - 1000 words

Sushi Digesting Genes Review - Article Example According to Ed Yong, microbes in their hundreds of trillion are found in Japanese bowels. He makes further findings that the cells are more than what humans have to the ratio of ten to one. Comparing ‘gut microbiome’ to an organ that aides the human body to breakdown molecules that the digestive system may not otherwise digest on its own. There is an observation that the molecules which are of carbohydrate nature are indigestible. He further comments that by consuming carbohydrates found in seaweeds and algae will help the digestive system to perform as they are rich in sulphur.Comparing the ability in the digestive tract to change genes, Ed Yong concedes that genes are not limited to the inheritance lineage. The human body has the capacity to change genes through transferring the horizontal gene. This involves to a large extent the genes kingdom that can be lent out to the preferred donor who receives Zobellia Galactanirorans a seagoing bacterium. In the Japanese cuisi ne, Nori which plays host to Zobellia is a common ingredient used in sushi wrapping and dish garnishing. The observation here is that upon consumption of the sushi, marine bacteria and algae are swallowed and become resident in the gut of the human body. The digestive system is tasked through genes to tackle the marine meals carbohydrates as well as the algae. There is an observation made that energy from an extra source prevails for the gut bacteria to break down the carbohydrates though there are some genetic remnants.

Underwater Acoustic Sensor Network (UASN)

Underwater Acoustic Sensor Network (UASN) CHAPTER1: Introduction Most of the earth surface is composed of water including fresh water from river, lakes etc and salt water from the sea. There are still many un-explored areas for such places. This needs significant research efforts and good communication systems. Wireless sensor network in aqueous medium has the ability to explore the underwater environment in details. For all applications of underwater, a good communication system as well as an effective routing protocol is needed. This will enable the underwater devices to communicate precisely. Underwater propagation speed varies with temperature, salinity and depth. By varying the underwater propagation speed at different depth, two scenarios can be achieved accurately namely: shallow and deep water. Shallow water consists of depth less than 200m and cylinder spreading. Deep water consists of depth greater or equal to 200 m and spherical spreading. In both shallow and deep water, different ambient noise and different spreading factor is applied. CHAPTER 2: Study of Underwater Acoustic Sensor Network (UASN) Application of UASN Wireless sensor network in aqueous medium also known as underwater sensor network has enabled a broad range of applications including: Environmental Monitoring Underwater sensor network can be used to monitor pollution like chemical, biological such as tracking of fish or micro-organisms, nuclear and oil leakage pollutions in bays, lakes or rivers [1]. Underwater sensor network can also be used to improve weather forecast, detect climate change, predict the effect of human activities on marine ecosystems, ocean currents and temperature change e.g. the global warming effect to ocean. Under Ocean Exploration Exploring minerals, oilfields or reservoir, determine routes for laying undersea cables and exploration valuable minerals can be done with such underwater sensor network. Disaster Prevention Sensor network that measure seismic activity from remote locations can provide tsunami warning to coastal areas, or study the effects of submarine earthquakes (seaquakes) [2] Equipment Monitoring Long-term equipment monitoring may be done with pre-installed infrastructure. Short-term equipment monitoring shares many requirements of long-term seismic monitoring, including the need for wireless (acoustic) communication, automatic configuration into a multihop network, localization (and hence time synchronization), and energy efficient operation Mine Reconnaissance By using acoustic sensors and optical sensors together, mine detection can be accomplished quickly and effectively. Assisted Monitoring Sensor can be used to discover danger on the seabed, locate dangerous rocks or shoals in shallow waters, mooring position, submerged wrecks and to perform bathymetry profiling. Information collection The main goal of communication network is the exchange of information inside the network and outside the network via a gateway or switch center. This application is used to share information among nodes and autonomous underwater vehicles. Characteristic of UASN Underwater Acoustic Networks (UANs), including but not limited to, Underwater Acoustic Sensor Networks (UASNs) and Autonomous Underwater Vehicle Networks (AUVNs) , are defined as networks composed of more than two nodes, using acoustic signals to communicate, for the purpose of underwater applications. UASNs and AUVNs are two important kinds of UANs. The former is composed of many sensor nodes, mostly for a monitoring purpose. The nodes are usually without or with limited capacity to move. The latter is composed of autonomous or unmanned vehicles with high mobility, deployed for applications that need mobility, e.g., exploration. An UAN can be an UASN, or an AUVN, or a combination of both. Acoustic communications, on the other hands, is defined as communication methods from one point to another by using acoustic signals. Network structure is not formed in acoustic point-to-point communications. Sound travels best through the water in comparison with electromagnetic waves and optical signals. Acoustic signal is sound signal waveform, usually produced by sonar for underwater applications. Acoustic signal processing extracts information from acoustic signals in the presence of noise and uncertainty. Underwater acoustic communications are mainly influenced by path loss, noise, multi-path, Doppler spread, and high and variable propagation delay. All these factors determine the temporal and spatial variability of the acoustic channel, and make the available bandwidth of the Underwater Acoustic channel (UW-A) limited and dramatically dependent on both range and frequency. Long-range systems that operate over several tens of kilometers may have a bandwidth of only a few kHz, while a short-range system operating over several tens of meters may have more than a hundred kHz bandwidth. These factors lead to low bit rate. Underwater acoustic communication links can be classified according to their range as very long, long, medium, short, and very short links. Acoustic links are also roughly classified as vertical and horizontal, according to the direction of the sound ray. Their propagation characteristics differ consistently, especially with respect to time dispersion, multi-path spreads, and delay variance. Acoustic signal is the only physical feasible tool that works in underwater environment. Compared with it, electromagnetic wave can only travel in water with short distance due to the high attenuation and absorption effect in underwater environment. It is found that the absorption of electromagnetic energy in sea water is about 45Ãâ€" ?f dB per kilometer, where f is frequency in Hertz; In contrast, the absorption of acoustic signal over most frequencies of interest is about three orders of magnitude lower [40]. Hereafter the factors that influence acoustic communications is analyzed in order to state the challenges posed by the underwater channels for underwater sensor networking. These include: Path loss Attenuation is mainly provoked by absorption due to conversion of acoustic energy into heat, which increases with distance and frequency. It is also caused by scattering a reverberation (on rough ocean surface and bottom), refraction, and dispersion (due to the displacement of the reflection point caused by wind on the surface). Water depth plays a key role in determining the attenuation. Geometric Spreading is the spreading of sound energy as a result of the expansion of the wavefronts. It increases with the propagation distance and is independent of frequency. There are two common kinds of geometric spreading: spherical (omni-directional point source), and cylindrical (horizontal radiation only). Noise Man made noise is mainly caused by machinery noise (pumps, reduction gears, power plants, etc.), and shipping activity (hull fouling, animal life on hull, cavitations), especially in areas encumbered with heavy vessel traffic. Ambient Noise is related to hydrodynamics (movement of water including tides, current, storms, wind, rain, etc.), seismic and biological phenomena. Multi-path Multi-path propagation may be responsible for severe degradation of the acoustic communication signal, since it generates Inter-Symbol Interference (ISI). The multi-path geometry depends on the link configuration. Vertical channels are characterized by little time dispersion, whereas horizontal channels may have extremely long multi-path spreads. The extent of the spreading is a strong function of depth and the distance between transmitter and receiver. High delay and delay variance The propagation speed in the UW-A channel is five orders of magnitude lower than in the radio channel. This large propagation delay (0.67 s/km) can reduce the throughput of the system considerably. The very high delay variance is even more harmful for efficient protocol design, as it prevents from accurately estimating the round trip time (RTT), which is the key parameter for many common communication protocols. Doppler spread The Doppler frequency spread can be significant in UW-A channels, causing degradation in the performance of digital communications: transmissions at a high data rate because many adjacent symbols to interfere at the receiver, requiring sophisticated signal processing to deal with the generated ISI. The Doppler spreading generates: a simple frequency translation, which is relatively easy for a receiver to compensate for a continuous spreading of frequencies, which constitutes a non-shifted signal, which is more difficult for a receiver to compensate for. If a channel has a Doppler spread with bandwidth B and a signal has symbol duration T, then there are approximately BT uncorrelated samples of its complex envelope. When BT is much less than unity, the channel is said to be under spread and the effects of the Doppler fading can be ignored, while, if greater than unity, it is overspread. Most of the described factors are caused by the chemical-physical properties of the water medium such as temperature, salinity and density, and by their spatio-temporal variations. These variations, together with the wave guide nature of the channel, because the acoustic channel to be temporally and spatially variable. In particular, the horizontal channel is by far more rapidly varying than the vertical channel, in both deep and shallow water. CHAPTER 3: Network Architecture Underwater sensor nodes: The underwater sensor nodes are deployed on the sea floor anchored to the ocean bottom [32]. The sensors are equipped with floating buoys to push the nodes upwards, thus they are relatively stationary nodes [3]. Using acoustic links, they relay data to underwater sink directly or via multi-hop path. Underwater sink nodes: Underwater sink nodes take charge of collecting data of underwater sensors deployed on the ocean bottom and then send to the surface sink node. They may be equipped with vertical and horizontal acoustic transducers. The horizontal transceiver is used to collect the sensors data and the vertical transceiver provides transmitting link between underwater sink and the surface sink node. Surface sink node: Surface sink node is attached on a floating buoy with satellite, radio frequency (RF) or cell phone technology to transmit data to shore in real time. 2D Model A reference architecture for two-dimensional underwater networks is shown in Figure. 1. A group of sensor nodes are anchored to the deep of the ocean. Underwater sensor nodes are interconnected to one or more underwater gateways by means of wireless acoustic links. Underwater-gateways are network devices in charge of relaying data from the ocean bottom network to a surface station. To achieve this objective, they are equipped with two acoustic transceivers, namely a vertical and a horizontal transceiver. The horizontal transceiver is used by the underwater-gateway to communicate with the sensor nodes in order to: send commands and configuration data to the sensors (underwater -gateway to sensors); collect monitored data (sensors to underwater -gateway). The vertical link is used by the underwater -gateways to relay data to a surface station. In deep water applications, vertical transceivers must be long range transceivers. The surface station is equipped with an acoustic transceiver that is able to handle multiple parallel communications with the deployed underwater -gateways. It is also endowed with a long range RF and/or satellite transmitter to communicate with the onshore sink (os-sink) and/or to a surface sink (s-sink). In shallow water, bottom-deployed sensors/modems may directly communicate with the surface buoy, with no specialized bottom node (underwater -gateway). 3D Model Three-dimensional underwater networks are used to detect and observe phenomena that cannot be adequately observed by means of ocean bottom sensor nodes, i.e., to perform cooperative sampling of the 3D ocean environment. In three-dimensional underwater networks, sensor nodes float at different depths to observe a phenomenon. In this architecture, given in Figure 2, each sensor is anchored to the ocean bottom and equipped with a floating buoy that can be inflated by a pump. The buoy pushes the sensor towards the ocean surface. The depth of the sensor can then be regulated by adjusting the length of the wire that connects the sensor to the anchor, by means of an electronically controlled engine that resides on the sensor. Sensing and communication coverage in a 3D environment are rigorously investigated in [8]. The diameter, minimum and maximum degree of the reachability graph that describes the network are derived as a function of the communication range, while different degrees of cov erage for the 3D environment are characterized as a function of the sensing range. 3D Model with AUV The above figure represents the third type of network architecture which consist of sensor nodes and Autonomous Underwater Vehicles (AUV) which act as mobile sensor nodes for ocean monitoring, underwater resource study, etc. CHAPTER 4: Differences between underwater and terrestrial Sensor Network An underwater acoustic channel is different from a ground-based radio channel from many aspects, including: Bandwidth is extremely limited. The attenuation of acoustic signal increases with frequency and range [6] [10]. Consequently, the feasible band is extremely small. For example, a short range system operating over several tens of meters may have available bandwidth of a hundred kHz; a medium-range system operating over several kilometers has a bandwidth on the order of ten kHz; and a long-range system operating over several tens of kilometers is limited to only a few kHz of bandwidth [11]. Propagation delay is long. The transmission speed of acoustic signals in salty water is around 1500 meter/s [22], which is a difference of five orders of magnitude lower than the speed of electromagnetic wave in free space. Correspondently, propagation delay in an underwater channel becomes significant. This is one of the essential characteristics of underwater channels and has profound implications on localization and time synchronization. The channel impulse response is not only spatially varied but also temporarily varied. The channel characteristics vary with time and highly depend on the location of the transmitter and receiver. The fluctuation nature of the channel causes the received signals easily distorted. There are two types of propagation paths: macro-multipaths, which are the deterministic propagation paths; and micro-multipath, which is a random signal fluctuation. The macro-multipaths are caused by both reflection at the boundaries (bottom, surface and any object in the water) and bending. Inter- Symbol Interference (ISI) thus occurs. Compared with the spread of its ground-based counterpart, which is on the order of several symbol intervals, ISI spreading in an underwater acoustic channel is several tens or hundred of symbol intervals for moderate to high data rate in the horizontal channel. Micro-multipath fluctuations are mainly caused by surface wave, which contributes the most to the time variability of shallow water channel. In deep water, internal waves impact the single-path random fluctuations [12][13]. Probability of bit error is much higher and temporary loss of connectivity (shadow zone) sometimes occurs, due to the extreme characteristics of the channel. Cost. While terrestrial sensor nodes are expected to become increasingly inexpensive, underwater sensors are expensive devices. This is especially due to the more complex underwater transceivers and to the hardware protection needed in the extreme underwater environment. Also, because of the low economy of scale caused by a small relative number of suppliers, underwater sensors are characterized by high cost. Deployment. While terrestrial sensor networks are densely deployed, in underwater, the deployment is generally more sparse. Power. The power needed for acoustic underwater communications is higher than in terrestrial radio communications because of the different physical layer technology (acoustic vs. RF waves), the higher distances, and more complex signal processing techniques implemented at the receivers to compensate for the impairments of the channel. Memory. While terrestrial sensor nodes have very limited storage capacity, underwater-sensors may need to be able to do some data caching as the underwater channel may be intermittent. Spatial Correlation. While the readings from terrestrial sensors are often correlated, this is more unlikely to happen in underwater networks due to the higher distance among sensors. CHAPTER 5: Layered of UASN The underwater architecture network consists of five layers, application, transport, network, data link and physical layer as shown in the figure below. As typical underwater systems have limited processing capability, the protocol has been kept as simple as possible without significantly compromising performance. The underwater sensor network specifications currently do not include any recommendations for authentication and encryption. These may be easily implemented at the application layer or via a spreading scheme at the physical layer. Each layer is described by a SAPI. The SAPI is defined in terms of messages being passed to and from the layer. The clients (usually higher layers) of a layer invoke the layer via a request (REQ). The layer responds to each REQ by a response (RSP). Errors are reported via an ERR RSP with error codes. If the layer needs to send unsolicited messages to the client, it does so via a notification (NTF). A layer communicates logically with its peer layer via protocol data units (PDU). As the peer-to-peer communication is symmetric, a layer may send a REQ PDU to its peer layer at any time. It would optionally respond to such a PDU with a RSP PDU. This is logically depicted in Figure below It may be desirable in some cases, that non-neighboring layers communicate with each other to achieve cross-layer optimization. This may be implemented by allowing REQ and RSP PDUs between any two layers in the protocol stack. The underwater sensor network specifications define detailed message structures for all SAPI messages. These message structures include message identifiers, data formats to be used, parameters and their possible values Physical layer The physical layer provides framing, modulation and error correction capability (via FEC). It provides primitives for sending and receiving packets. It may also provide additional functionality such as parameter settings, parameter recommendation, carrier sensing, etc. At first underwater channel development was based on non-coherent frequency shift keying (FSK) modulation, since it relies on energy detection. Thus, it does not require phase tracking, which is a very difficult task mainly because of the Doppler-spread in the underwater acoustic channel. Although non-coherent modulation schemes are characterized by high power efficiency, their low bandwidth efficiency makes them unsuitable for high data rate multiuser networks. Hence, coherent modulation techniques have been developed for long-range, high-throughput systems. In the last years, fully coherent modulation techniques, such as phase shift keying (PSK) and quadrature amplitude modulation (QAM), have become practical due to the availability of powerful digital processing. Channel equalization techniques are exploited to leverage the effect of the inter-symbol interference (ISI), instead of trying to avoid or suppress it. Decision-feedback equalizers (DFEs) track the complex, relatively slowly varying channel response and thus provide high throughput when the channel is slowly varying. Conversely, when the channel varies faster, it is necessary to combine the DFE with a Phase Locked Loop (PLL) [9], which estimates and compensates for the phase offset in a rapid, stable manner. The use of decision feedback equalization and phase-locked loops is driven by the complexity and time variability of ocean channel impulse responses. Differential phase shift keying (DPSK) serves as an intermediate solution between incoherent and fully coherent systems in terms of bandwidth efficiency. DPSK encodes information relative to the previous symbol rather than to an arbitrary fixed reference in the signal phase and may be referred to as a partially coherent modulation. While this strategy substantially alleviates carrier phase-tracking requirements, the penalty is an increased error probability over PSK at an equivalent data rate. Another promising solution for underwater communications is the orthogonal frequency division multiplexing (OFDM) spread spectrum technique, which is particularly efficient when noise is spread over a large portion of the available bandwidth. OFDM is frequently referred to as multicarrier modulation because it transmits signals over multiple sub-carriers simultaneously. In particular, sub-carriers that experience higher SNR, are allotted with a higher number of bits, whereas less bits are allotted to sub-carriers experiencing attenuation, according to the concept of bit loading, which requires channel estimation. Since the symbol duration for each individual carrier increases, OFDM systems perform robustly in severe multi-path environments, and achieve a high spectral efficiency. Many of the techniques discussed above require underwater channel estimation, which can be achieved by means of probe packets [17]. An accurate estimate of the channel can be obtained with a high probing rate and/or with a large probe packet size, which however result in high overhead, and in the consequent drain of channel capacity and energy. Data link layer (MAC layer) The data link layer provides single hop data transmission capability; it will not be able to transmit a packet successfully if the destination node is not directly accessible from the source node. It may include some degree of reliability. It may also provide error detection capability (e.g. CRC check). In case of a shared medium, the data link layer must include the medium access control (MAC) sub-layer. Frequency division multiple access (FDMA) is not suitable for underwater sensor network due to the narrow bandwidth in underwater acoustic channels and the vulnerability of limited band systems to fading and multipath. Time division multiple access (TDMA) shows limited bandwidth efficiency because of the long time guards required in the underwater acoustic channel. In fact, long time guards must be designed to account for the large propagation delay and delay variance of the underwater channel in order to minimize packet collisions from adjacent time slots. Moreover, the variable delay makes it very challenging to realize a precise synchronization, with a common timing reference, which is required for TDMA. Carrier sense multiple access (CSMA) prevents collisions with the ongoing transmission at the transmitter side. To prevent collisions at the receiver side, however, it is necessary to add a guard time between transmissions dimensioned according to the maximum propagation delay in the network. This makes the protocol dramatically inefficient for underwater acoustic sensor network. The use of contention-based techniques that rely on handshaking mechanisms such as RTS/ CTS in shared medium access is impractical in underwater, for the following reasons: large delays in the propagation of RTS/CTS control packets lead to low throughput; due to the high propagation delay of underwater acoustic channels, when carrier sense is used, as in 802.11, it is more likely that the channel be sensed idle while a transmission is ongoing, since the signal may not have reached the receiver yet; the high variability of delay in handshaking packets makes it impractical to predict the start and finish time of the transmissions of other stations. Thus, collisions are highly likely to occur. Code division multiple access (CDMA) is quite robust to frequency selective fading caused by underwater multi-paths, since it distinguishes simultaneous signals transmitted by multiple devices by means of pseudo-noise codes that are used for spreading the user signal over the entire available band. CDMA allows reducing the number of packet retransmissions, which results in decreased battery consumption and increased network throughput. In conclusion, although the high delay spread which characterizes the horizontal link in underwater channels makes it difficult to maintain synchronization among the stations, especially when orthogonal code techniques are used [17], CDMA is a promising multiple access technique for underwater acoustic networks. This is particularly true in shallow water, where multi-paths and Doppler- spreading plays a key role in the communication performance. Network layer (Routing) The network layer is in charge of determining the path between a source (the sensor that samples a physical phenomenon) and a destination node (usually the surface station). In general, while many impairments of the underwater acoustic channel are adequately addressed at the physical and data link layers, some other characteristics, such as the extremely long propagation delays, are better addressed at the network layer. Basically, there are two methods of routing. The first one is virtual circuit routing and the second one is packet-switch routing. In virtual circuit routing, the networks use virtual circuits to decide on the path at the beginning of the network operation. Virtual-circuit-switch routing protocols can be a better choice for underwater acoustic networks. The reasons are: Underwater acoustic networks are typical asymmetric instead of symmetric. However, packet switched routing protocols are proposed for symmetric network architecture; Virtual-circuit-switch routing protocols work robust against link failure, which is critical in underwater environment; and Virtual-circuit-switch routing protocols have less signal overhead and low latency, which are needed for underwater acoustic channel environment. However, virtual-circuit-switch routing protocols usually lack of flexibility. In packet-switch routing, every node that is part of the transmission makes its own routing decision, i.e., decides its next hop to relay the packet. Packet-switch routing can be further classified into Proactive routing, Reactive and geographical routing protocols. Most routing protocols for ground-based wireless networks are packet-switch based. Proactive routing protocols attempt to minimize the message latency by maintaining up-to-date routing information at all times from each node to any other node. It broadcasts control packets that contain routing table information. Typical protocols include Destination Sequence Distance Vector (DSDV) [28] and Temporally Ordered Routing Algorithm (TORA). However, proactive routing protocols provoke a large signaling overhead to establish routes for the first time and each time the network topology changes. It may not be a good fit in underwater environment due to the high probability of link failure and extremely limited bandwidth there. Reactive routing protocols only initiate a route discovery process upon request. Correspondently, each node does not need to maintain a sizable look-up table for routing. This kind of routing protocols is more suitable for dynamic environment like ad hoc wireless networks. Typical protocol examples are Ad hoc On-demand Distance Vector (AODV) [23], and Dynamic Source Routing (DSR) [27]. The shortage of reactive routing protocols is its high latency to establish routing. Similar to its proactive counterpart, flooding of control packets to establish paths is needed, which brings significant signal overhead. The high latency could become much deteriorated in underwater environment because of the much slower propagation speed of acoustic signal compared with the radio wave in the air. Geographic routing (also called georouting or position-based routing) is a routing principle that relies on geographic position information. It is mainly proposed for wireless networks and based on the idea that the source sends a message to the geographic location of the destination instead of using the network address. Geographic routing requires that each node can determine its own location and that the source is aware of the location of the destination. With this information a message can be routed to the destination without knowledge of the network topology or a prior route discovery. Transport layer A transport layer protocol is needed in underwater sensor network not only to achieve reliable collective transport of event features, but also to perform flow control and congestion control. The primary objective is to save scarce sensor resources and increase the network efficiency. A reliable transport protocol should guarantee that the applications be able to correctly identify event features estimated by the sensor network. Congestion control is needed to prevent the network from being congested by excessive data with respect to the network capacity, while flow control is needed to avoid that network devices with limited memory are overwhelmed by data transmissions. Most existing TCP implementations are unsuited for the underwater environment, since the flow control functionality is based on a window- based mechanism that relies on an accurate esteem of the round trip time (RTT), which is twice the end-to-end delay from source to destination. Rate-based transport protocols seem also unsuited for this challenging environment. They still rely on feedback control messages sent back by the destination to dynamically adapt the transmission rate, i.e., to decrease the transmission rate when packet loss is experienced or to increase it otherwise. The high delay and delay variance can thus cause instability in the feedback control. Furthermore, due to the unreliability of the acoustic channel, it is necessary to distinguish between packet losses due to the high bit error rate of the acoustic channel, from those caused by packets being dropped from the queues of sensor nodes due to network congestion. In terrestrial, assume that congestion is the only cause for packet loss and the solution lies on decreasing the transmission rate, but in underwater sensor network if the packet loss is due to bad channel then the transmission rate should not be decreased to preserve throughput efficiency. Transport layer functionalities can be tightly integrated with data link layer functionalities in a cross-layer module. The purpose of such an integrated module is to make the information about the condition of the variable underwater channel available also at the transport layer. In fact, usually the state of the channel is known only at the physical and channel access sub-layers, while the design principle of layer separation makes this information transparent to the higher layers. This integration allows maximizing the Underwater Acoustic Sensor Network (UASN) Underwater Acoustic Sensor Network (UASN) CHAPTER1: Introduction Most of the earth surface is composed of water including fresh water from river, lakes etc and salt water from the sea. There are still many un-explored areas for such places. This needs significant research efforts and good communication systems. Wireless sensor network in aqueous medium has the ability to explore the underwater environment in details. For all applications of underwater, a good communication system as well as an effective routing protocol is needed. This will enable the underwater devices to communicate precisely. Underwater propagation speed varies with temperature, salinity and depth. By varying the underwater propagation speed at different depth, two scenarios can be achieved accurately namely: shallow and deep water. Shallow water consists of depth less than 200m and cylinder spreading. Deep water consists of depth greater or equal to 200 m and spherical spreading. In both shallow and deep water, different ambient noise and different spreading factor is applied. CHAPTER 2: Study of Underwater Acoustic Sensor Network (UASN) Application of UASN Wireless sensor network in aqueous medium also known as underwater sensor network has enabled a broad range of applications including: Environmental Monitoring Underwater sensor network can be used to monitor pollution like chemical, biological such as tracking of fish or micro-organisms, nuclear and oil leakage pollutions in bays, lakes or rivers [1]. Underwater sensor network can also be used to improve weather forecast, detect climate change, predict the effect of human activities on marine ecosystems, ocean currents and temperature change e.g. the global warming effect to ocean. Under Ocean Exploration Exploring minerals, oilfields or reservoir, determine routes for laying undersea cables and exploration valuable minerals can be done with such underwater sensor network. Disaster Prevention Sensor network that measure seismic activity from remote locations can provide tsunami warning to coastal areas, or study the effects of submarine earthquakes (seaquakes) [2] Equipment Monitoring Long-term equipment monitoring may be done with pre-installed infrastructure. Short-term equipment monitoring shares many requirements of long-term seismic monitoring, including the need for wireless (acoustic) communication, automatic configuration into a multihop network, localization (and hence time synchronization), and energy efficient operation Mine Reconnaissance By using acoustic sensors and optical sensors together, mine detection can be accomplished quickly and effectively. Assisted Monitoring Sensor can be used to discover danger on the seabed, locate dangerous rocks or shoals in shallow waters, mooring position, submerged wrecks and to perform bathymetry profiling. Information collection The main goal of communication network is the exchange of information inside the network and outside the network via a gateway or switch center. This application is used to share information among nodes and autonomous underwater vehicles. Characteristic of UASN Underwater Acoustic Networks (UANs), including but not limited to, Underwater Acoustic Sensor Networks (UASNs) and Autonomous Underwater Vehicle Networks (AUVNs) , are defined as networks composed of more than two nodes, using acoustic signals to communicate, for the purpose of underwater applications. UASNs and AUVNs are two important kinds of UANs. The former is composed of many sensor nodes, mostly for a monitoring purpose. The nodes are usually without or with limited capacity to move. The latter is composed of autonomous or unmanned vehicles with high mobility, deployed for applications that need mobility, e.g., exploration. An UAN can be an UASN, or an AUVN, or a combination of both. Acoustic communications, on the other hands, is defined as communication methods from one point to another by using acoustic signals. Network structure is not formed in acoustic point-to-point communications. Sound travels best through the water in comparison with electromagnetic waves and optical signals. Acoustic signal is sound signal waveform, usually produced by sonar for underwater applications. Acoustic signal processing extracts information from acoustic signals in the presence of noise and uncertainty. Underwater acoustic communications are mainly influenced by path loss, noise, multi-path, Doppler spread, and high and variable propagation delay. All these factors determine the temporal and spatial variability of the acoustic channel, and make the available bandwidth of the Underwater Acoustic channel (UW-A) limited and dramatically dependent on both range and frequency. Long-range systems that operate over several tens of kilometers may have a bandwidth of only a few kHz, while a short-range system operating over several tens of meters may have more than a hundred kHz bandwidth. These factors lead to low bit rate. Underwater acoustic communication links can be classified according to their range as very long, long, medium, short, and very short links. Acoustic links are also roughly classified as vertical and horizontal, according to the direction of the sound ray. Their propagation characteristics differ consistently, especially with respect to time dispersion, multi-path spreads, and delay variance. Acoustic signal is the only physical feasible tool that works in underwater environment. Compared with it, electromagnetic wave can only travel in water with short distance due to the high attenuation and absorption effect in underwater environment. It is found that the absorption of electromagnetic energy in sea water is about 45Ãâ€" ?f dB per kilometer, where f is frequency in Hertz; In contrast, the absorption of acoustic signal over most frequencies of interest is about three orders of magnitude lower [40]. Hereafter the factors that influence acoustic communications is analyzed in order to state the challenges posed by the underwater channels for underwater sensor networking. These include: Path loss Attenuation is mainly provoked by absorption due to conversion of acoustic energy into heat, which increases with distance and frequency. It is also caused by scattering a reverberation (on rough ocean surface and bottom), refraction, and dispersion (due to the displacement of the reflection point caused by wind on the surface). Water depth plays a key role in determining the attenuation. Geometric Spreading is the spreading of sound energy as a result of the expansion of the wavefronts. It increases with the propagation distance and is independent of frequency. There are two common kinds of geometric spreading: spherical (omni-directional point source), and cylindrical (horizontal radiation only). Noise Man made noise is mainly caused by machinery noise (pumps, reduction gears, power plants, etc.), and shipping activity (hull fouling, animal life on hull, cavitations), especially in areas encumbered with heavy vessel traffic. Ambient Noise is related to hydrodynamics (movement of water including tides, current, storms, wind, rain, etc.), seismic and biological phenomena. Multi-path Multi-path propagation may be responsible for severe degradation of the acoustic communication signal, since it generates Inter-Symbol Interference (ISI). The multi-path geometry depends on the link configuration. Vertical channels are characterized by little time dispersion, whereas horizontal channels may have extremely long multi-path spreads. The extent of the spreading is a strong function of depth and the distance between transmitter and receiver. High delay and delay variance The propagation speed in the UW-A channel is five orders of magnitude lower than in the radio channel. This large propagation delay (0.67 s/km) can reduce the throughput of the system considerably. The very high delay variance is even more harmful for efficient protocol design, as it prevents from accurately estimating the round trip time (RTT), which is the key parameter for many common communication protocols. Doppler spread The Doppler frequency spread can be significant in UW-A channels, causing degradation in the performance of digital communications: transmissions at a high data rate because many adjacent symbols to interfere at the receiver, requiring sophisticated signal processing to deal with the generated ISI. The Doppler spreading generates: a simple frequency translation, which is relatively easy for a receiver to compensate for a continuous spreading of frequencies, which constitutes a non-shifted signal, which is more difficult for a receiver to compensate for. If a channel has a Doppler spread with bandwidth B and a signal has symbol duration T, then there are approximately BT uncorrelated samples of its complex envelope. When BT is much less than unity, the channel is said to be under spread and the effects of the Doppler fading can be ignored, while, if greater than unity, it is overspread. Most of the described factors are caused by the chemical-physical properties of the water medium such as temperature, salinity and density, and by their spatio-temporal variations. These variations, together with the wave guide nature of the channel, because the acoustic channel to be temporally and spatially variable. In particular, the horizontal channel is by far more rapidly varying than the vertical channel, in both deep and shallow water. CHAPTER 3: Network Architecture Underwater sensor nodes: The underwater sensor nodes are deployed on the sea floor anchored to the ocean bottom [32]. The sensors are equipped with floating buoys to push the nodes upwards, thus they are relatively stationary nodes [3]. Using acoustic links, they relay data to underwater sink directly or via multi-hop path. Underwater sink nodes: Underwater sink nodes take charge of collecting data of underwater sensors deployed on the ocean bottom and then send to the surface sink node. They may be equipped with vertical and horizontal acoustic transducers. The horizontal transceiver is used to collect the sensors data and the vertical transceiver provides transmitting link between underwater sink and the surface sink node. Surface sink node: Surface sink node is attached on a floating buoy with satellite, radio frequency (RF) or cell phone technology to transmit data to shore in real time. 2D Model A reference architecture for two-dimensional underwater networks is shown in Figure. 1. A group of sensor nodes are anchored to the deep of the ocean. Underwater sensor nodes are interconnected to one or more underwater gateways by means of wireless acoustic links. Underwater-gateways are network devices in charge of relaying data from the ocean bottom network to a surface station. To achieve this objective, they are equipped with two acoustic transceivers, namely a vertical and a horizontal transceiver. The horizontal transceiver is used by the underwater-gateway to communicate with the sensor nodes in order to: send commands and configuration data to the sensors (underwater -gateway to sensors); collect monitored data (sensors to underwater -gateway). The vertical link is used by the underwater -gateways to relay data to a surface station. In deep water applications, vertical transceivers must be long range transceivers. The surface station is equipped with an acoustic transceiver that is able to handle multiple parallel communications with the deployed underwater -gateways. It is also endowed with a long range RF and/or satellite transmitter to communicate with the onshore sink (os-sink) and/or to a surface sink (s-sink). In shallow water, bottom-deployed sensors/modems may directly communicate with the surface buoy, with no specialized bottom node (underwater -gateway). 3D Model Three-dimensional underwater networks are used to detect and observe phenomena that cannot be adequately observed by means of ocean bottom sensor nodes, i.e., to perform cooperative sampling of the 3D ocean environment. In three-dimensional underwater networks, sensor nodes float at different depths to observe a phenomenon. In this architecture, given in Figure 2, each sensor is anchored to the ocean bottom and equipped with a floating buoy that can be inflated by a pump. The buoy pushes the sensor towards the ocean surface. The depth of the sensor can then be regulated by adjusting the length of the wire that connects the sensor to the anchor, by means of an electronically controlled engine that resides on the sensor. Sensing and communication coverage in a 3D environment are rigorously investigated in [8]. The diameter, minimum and maximum degree of the reachability graph that describes the network are derived as a function of the communication range, while different degrees of cov erage for the 3D environment are characterized as a function of the sensing range. 3D Model with AUV The above figure represents the third type of network architecture which consist of sensor nodes and Autonomous Underwater Vehicles (AUV) which act as mobile sensor nodes for ocean monitoring, underwater resource study, etc. CHAPTER 4: Differences between underwater and terrestrial Sensor Network An underwater acoustic channel is different from a ground-based radio channel from many aspects, including: Bandwidth is extremely limited. The attenuation of acoustic signal increases with frequency and range [6] [10]. Consequently, the feasible band is extremely small. For example, a short range system operating over several tens of meters may have available bandwidth of a hundred kHz; a medium-range system operating over several kilometers has a bandwidth on the order of ten kHz; and a long-range system operating over several tens of kilometers is limited to only a few kHz of bandwidth [11]. Propagation delay is long. The transmission speed of acoustic signals in salty water is around 1500 meter/s [22], which is a difference of five orders of magnitude lower than the speed of electromagnetic wave in free space. Correspondently, propagation delay in an underwater channel becomes significant. This is one of the essential characteristics of underwater channels and has profound implications on localization and time synchronization. The channel impulse response is not only spatially varied but also temporarily varied. The channel characteristics vary with time and highly depend on the location of the transmitter and receiver. The fluctuation nature of the channel causes the received signals easily distorted. There are two types of propagation paths: macro-multipaths, which are the deterministic propagation paths; and micro-multipath, which is a random signal fluctuation. The macro-multipaths are caused by both reflection at the boundaries (bottom, surface and any object in the water) and bending. Inter- Symbol Interference (ISI) thus occurs. Compared with the spread of its ground-based counterpart, which is on the order of several symbol intervals, ISI spreading in an underwater acoustic channel is several tens or hundred of symbol intervals for moderate to high data rate in the horizontal channel. Micro-multipath fluctuations are mainly caused by surface wave, which contributes the most to the time variability of shallow water channel. In deep water, internal waves impact the single-path random fluctuations [12][13]. Probability of bit error is much higher and temporary loss of connectivity (shadow zone) sometimes occurs, due to the extreme characteristics of the channel. Cost. While terrestrial sensor nodes are expected to become increasingly inexpensive, underwater sensors are expensive devices. This is especially due to the more complex underwater transceivers and to the hardware protection needed in the extreme underwater environment. Also, because of the low economy of scale caused by a small relative number of suppliers, underwater sensors are characterized by high cost. Deployment. While terrestrial sensor networks are densely deployed, in underwater, the deployment is generally more sparse. Power. The power needed for acoustic underwater communications is higher than in terrestrial radio communications because of the different physical layer technology (acoustic vs. RF waves), the higher distances, and more complex signal processing techniques implemented at the receivers to compensate for the impairments of the channel. Memory. While terrestrial sensor nodes have very limited storage capacity, underwater-sensors may need to be able to do some data caching as the underwater channel may be intermittent. Spatial Correlation. While the readings from terrestrial sensors are often correlated, this is more unlikely to happen in underwater networks due to the higher distance among sensors. CHAPTER 5: Layered of UASN The underwater architecture network consists of five layers, application, transport, network, data link and physical layer as shown in the figure below. As typical underwater systems have limited processing capability, the protocol has been kept as simple as possible without significantly compromising performance. The underwater sensor network specifications currently do not include any recommendations for authentication and encryption. These may be easily implemented at the application layer or via a spreading scheme at the physical layer. Each layer is described by a SAPI. The SAPI is defined in terms of messages being passed to and from the layer. The clients (usually higher layers) of a layer invoke the layer via a request (REQ). The layer responds to each REQ by a response (RSP). Errors are reported via an ERR RSP with error codes. If the layer needs to send unsolicited messages to the client, it does so via a notification (NTF). A layer communicates logically with its peer layer via protocol data units (PDU). As the peer-to-peer communication is symmetric, a layer may send a REQ PDU to its peer layer at any time. It would optionally respond to such a PDU with a RSP PDU. This is logically depicted in Figure below It may be desirable in some cases, that non-neighboring layers communicate with each other to achieve cross-layer optimization. This may be implemented by allowing REQ and RSP PDUs between any two layers in the protocol stack. The underwater sensor network specifications define detailed message structures for all SAPI messages. These message structures include message identifiers, data formats to be used, parameters and their possible values Physical layer The physical layer provides framing, modulation and error correction capability (via FEC). It provides primitives for sending and receiving packets. It may also provide additional functionality such as parameter settings, parameter recommendation, carrier sensing, etc. At first underwater channel development was based on non-coherent frequency shift keying (FSK) modulation, since it relies on energy detection. Thus, it does not require phase tracking, which is a very difficult task mainly because of the Doppler-spread in the underwater acoustic channel. Although non-coherent modulation schemes are characterized by high power efficiency, their low bandwidth efficiency makes them unsuitable for high data rate multiuser networks. Hence, coherent modulation techniques have been developed for long-range, high-throughput systems. In the last years, fully coherent modulation techniques, such as phase shift keying (PSK) and quadrature amplitude modulation (QAM), have become practical due to the availability of powerful digital processing. Channel equalization techniques are exploited to leverage the effect of the inter-symbol interference (ISI), instead of trying to avoid or suppress it. Decision-feedback equalizers (DFEs) track the complex, relatively slowly varying channel response and thus provide high throughput when the channel is slowly varying. Conversely, when the channel varies faster, it is necessary to combine the DFE with a Phase Locked Loop (PLL) [9], which estimates and compensates for the phase offset in a rapid, stable manner. The use of decision feedback equalization and phase-locked loops is driven by the complexity and time variability of ocean channel impulse responses. Differential phase shift keying (DPSK) serves as an intermediate solution between incoherent and fully coherent systems in terms of bandwidth efficiency. DPSK encodes information relative to the previous symbol rather than to an arbitrary fixed reference in the signal phase and may be referred to as a partially coherent modulation. While this strategy substantially alleviates carrier phase-tracking requirements, the penalty is an increased error probability over PSK at an equivalent data rate. Another promising solution for underwater communications is the orthogonal frequency division multiplexing (OFDM) spread spectrum technique, which is particularly efficient when noise is spread over a large portion of the available bandwidth. OFDM is frequently referred to as multicarrier modulation because it transmits signals over multiple sub-carriers simultaneously. In particular, sub-carriers that experience higher SNR, are allotted with a higher number of bits, whereas less bits are allotted to sub-carriers experiencing attenuation, according to the concept of bit loading, which requires channel estimation. Since the symbol duration for each individual carrier increases, OFDM systems perform robustly in severe multi-path environments, and achieve a high spectral efficiency. Many of the techniques discussed above require underwater channel estimation, which can be achieved by means of probe packets [17]. An accurate estimate of the channel can be obtained with a high probing rate and/or with a large probe packet size, which however result in high overhead, and in the consequent drain of channel capacity and energy. Data link layer (MAC layer) The data link layer provides single hop data transmission capability; it will not be able to transmit a packet successfully if the destination node is not directly accessible from the source node. It may include some degree of reliability. It may also provide error detection capability (e.g. CRC check). In case of a shared medium, the data link layer must include the medium access control (MAC) sub-layer. Frequency division multiple access (FDMA) is not suitable for underwater sensor network due to the narrow bandwidth in underwater acoustic channels and the vulnerability of limited band systems to fading and multipath. Time division multiple access (TDMA) shows limited bandwidth efficiency because of the long time guards required in the underwater acoustic channel. In fact, long time guards must be designed to account for the large propagation delay and delay variance of the underwater channel in order to minimize packet collisions from adjacent time slots. Moreover, the variable delay makes it very challenging to realize a precise synchronization, with a common timing reference, which is required for TDMA. Carrier sense multiple access (CSMA) prevents collisions with the ongoing transmission at the transmitter side. To prevent collisions at the receiver side, however, it is necessary to add a guard time between transmissions dimensioned according to the maximum propagation delay in the network. This makes the protocol dramatically inefficient for underwater acoustic sensor network. The use of contention-based techniques that rely on handshaking mechanisms such as RTS/ CTS in shared medium access is impractical in underwater, for the following reasons: large delays in the propagation of RTS/CTS control packets lead to low throughput; due to the high propagation delay of underwater acoustic channels, when carrier sense is used, as in 802.11, it is more likely that the channel be sensed idle while a transmission is ongoing, since the signal may not have reached the receiver yet; the high variability of delay in handshaking packets makes it impractical to predict the start and finish time of the transmissions of other stations. Thus, collisions are highly likely to occur. Code division multiple access (CDMA) is quite robust to frequency selective fading caused by underwater multi-paths, since it distinguishes simultaneous signals transmitted by multiple devices by means of pseudo-noise codes that are used for spreading the user signal over the entire available band. CDMA allows reducing the number of packet retransmissions, which results in decreased battery consumption and increased network throughput. In conclusion, although the high delay spread which characterizes the horizontal link in underwater channels makes it difficult to maintain synchronization among the stations, especially when orthogonal code techniques are used [17], CDMA is a promising multiple access technique for underwater acoustic networks. This is particularly true in shallow water, where multi-paths and Doppler- spreading plays a key role in the communication performance. Network layer (Routing) The network layer is in charge of determining the path between a source (the sensor that samples a physical phenomenon) and a destination node (usually the surface station). In general, while many impairments of the underwater acoustic channel are adequately addressed at the physical and data link layers, some other characteristics, such as the extremely long propagation delays, are better addressed at the network layer. Basically, there are two methods of routing. The first one is virtual circuit routing and the second one is packet-switch routing. In virtual circuit routing, the networks use virtual circuits to decide on the path at the beginning of the network operation. Virtual-circuit-switch routing protocols can be a better choice for underwater acoustic networks. The reasons are: Underwater acoustic networks are typical asymmetric instead of symmetric. However, packet switched routing protocols are proposed for symmetric network architecture; Virtual-circuit-switch routing protocols work robust against link failure, which is critical in underwater environment; and Virtual-circuit-switch routing protocols have less signal overhead and low latency, which are needed for underwater acoustic channel environment. However, virtual-circuit-switch routing protocols usually lack of flexibility. In packet-switch routing, every node that is part of the transmission makes its own routing decision, i.e., decides its next hop to relay the packet. Packet-switch routing can be further classified into Proactive routing, Reactive and geographical routing protocols. Most routing protocols for ground-based wireless networks are packet-switch based. Proactive routing protocols attempt to minimize the message latency by maintaining up-to-date routing information at all times from each node to any other node. It broadcasts control packets that contain routing table information. Typical protocols include Destination Sequence Distance Vector (DSDV) [28] and Temporally Ordered Routing Algorithm (TORA). However, proactive routing protocols provoke a large signaling overhead to establish routes for the first time and each time the network topology changes. It may not be a good fit in underwater environment due to the high probability of link failure and extremely limited bandwidth there. Reactive routing protocols only initiate a route discovery process upon request. Correspondently, each node does not need to maintain a sizable look-up table for routing. This kind of routing protocols is more suitable for dynamic environment like ad hoc wireless networks. Typical protocol examples are Ad hoc On-demand Distance Vector (AODV) [23], and Dynamic Source Routing (DSR) [27]. The shortage of reactive routing protocols is its high latency to establish routing. Similar to its proactive counterpart, flooding of control packets to establish paths is needed, which brings significant signal overhead. The high latency could become much deteriorated in underwater environment because of the much slower propagation speed of acoustic signal compared with the radio wave in the air. Geographic routing (also called georouting or position-based routing) is a routing principle that relies on geographic position information. It is mainly proposed for wireless networks and based on the idea that the source sends a message to the geographic location of the destination instead of using the network address. Geographic routing requires that each node can determine its own location and that the source is aware of the location of the destination. With this information a message can be routed to the destination without knowledge of the network topology or a prior route discovery. Transport layer A transport layer protocol is needed in underwater sensor network not only to achieve reliable collective transport of event features, but also to perform flow control and congestion control. The primary objective is to save scarce sensor resources and increase the network efficiency. A reliable transport protocol should guarantee that the applications be able to correctly identify event features estimated by the sensor network. Congestion control is needed to prevent the network from being congested by excessive data with respect to the network capacity, while flow control is needed to avoid that network devices with limited memory are overwhelmed by data transmissions. Most existing TCP implementations are unsuited for the underwater environment, since the flow control functionality is based on a window- based mechanism that relies on an accurate esteem of the round trip time (RTT), which is twice the end-to-end delay from source to destination. Rate-based transport protocols seem also unsuited for this challenging environment. They still rely on feedback control messages sent back by the destination to dynamically adapt the transmission rate, i.e., to decrease the transmission rate when packet loss is experienced or to increase it otherwise. The high delay and delay variance can thus cause instability in the feedback control. Furthermore, due to the unreliability of the acoustic channel, it is necessary to distinguish between packet losses due to the high bit error rate of the acoustic channel, from those caused by packets being dropped from the queues of sensor nodes due to network congestion. In terrestrial, assume that congestion is the only cause for packet loss and the solution lies on decreasing the transmission rate, but in underwater sensor network if the packet loss is due to bad channel then the transmission rate should not be decreased to preserve throughput efficiency. Transport layer functionalities can be tightly integrated with data link layer functionalities in a cross-layer module. The purpose of such an integrated module is to make the information about the condition of the variable underwater channel available also at the transport layer. In fact, usually the state of the channel is known only at the physical and channel access sub-layers, while the design principle of layer separation makes this information transparent to the higher layers. This integration allows maximizing the