Clinical condition Essay Example | Topics and Well Written Essays - 250 words

Clinical condition - Essay Example It is worth noting that patients with this medical complication may also experience weight loss in spite of increased appetite and hair loss (Zaidi 89). Other symptoms of the disease can only be identified through physical examination of the patient by a medical practitioner. These include excessive lacrimation, premature ventricular expansions and contractions and rigid thyroid (MacLachlan, Sandra, & Basil 52). A clinical examination of a patient suffering from Graves’ disease may provide the following results; for instance, a Graves’ disease patient can be examined with rapid heartbeats, muscular weakness and protuberance of the eyes (either one or both eyes). Fatigue, increased appetite and weight loss are also other diagnostic results of Graves’ disease (MacLachlan, Sandra, & Basil 76). Medical practitioners have characterized Graves’ disease as a condition whose causes are not readily determined and have since concluded that there seems to be a genetic predisposition for the condition. This is an implication that some people are more likely to contract the disease as compared to others and this is as a result of their genetic inheritance. Nonetheless, a bacterium called Yersinia Enterocolitica has since been associated with the disease. Medical specialists have discovered that the bacterium contributes to the advance of thyroid autoimmunity; which is closely attributed to Graves’ disease (Zaidi 95). Treatment of Graves’ disease must be administered by a certified medical practitioner and includes the prescription of anti-thyroid drugs. This type of medication is known to limit the secretion of thyroid hormone. Medication is always given for between six months and two years. It is worth noting that the administration of these drugs into the human body have side effects of potentially grave reduction of the level of white blood cells (Zaidi 109). Zaidi,

Men become victims of their misplaced trust in false friends Essay

Men become victims of their misplaced trust in false friends - Essay Example It is about the story of a prisoner, Gregory, who places complete trust in the friendship of his enemy. Gregory was given two chances to escape to save his own life but he fails to run away. Gregory is materialistic. He cares only for his present which is comfortable enough for him. He does not realize his friend must obey his superior and that means that his friend will kill him. Gregory is shot but he does not die immediately. He hangs on to his friend for life or for death. His friend is forced to shoot him several times in order to make a clean killing. His friend honors Gregory by not humiliating his body with a public hanging. Gregory thinks that his friend has breached his trust by shooting him. His soldier friend blames Gregory's stupidity for his death.Nabil Gorgy wrote Cairo Is a Small City in 1983. This story is about Engineer Adil Salim, who is killed in revenge for his murder of a bedouin man, Mubarak bin Rabia. Adil is a proud man who has a big ego. He thinks of himself being intelligent because he is educated as an engineer. He makes the false overture of drawing attention to himself by his blatant courtship of a beautiful bedouin girl named Salma. He is watched and recognized as the murderer of Mubarak. The bedouins plot their vengeance craftily. They are above reproach as they use the girl, Salma, as bait to ensnare Adil. Adil falls into their trap and is killed. Adil is a victim of his own carelessness, ego, lust, stupidity and trusting nature. Cairo Is a Small City uses an omniscient narrator. This essay uses these two short stories to compare the similarities on how trust is betrayed. The essay takes the position that the two victims, Gregory and Adil, deserve to die, because of the fault of gullible trust in their personal characters. Adil trusted in the shopkeeper's strategy of befriending the woman because he saw that it worked. Gorgy and the omniscient narrator want to blame the shopkeeper for showing Adil the flirtatious method of bartering for the woman's affections. The narration says; '...had it not been for that day, Adil's mind would not have given birth to the plan he was determined, whatever the cost, to put through, because of that woman who had bewitched his heart.' (Hirschberg & Hirschberg 24). Adil does not question the consequences if the trust goes wrong. He is gullible and the fault is his alone. Adil trusted in his own bravery. The evidence that supports this argument is in the narration; ''As every man, according to Adil's philosophy of life, had within him a devil, it was sometimes better to follow this devil in order to placate him and avoid his tyranny.' (Hirschberg & Hirschberg 24). When Salma's father asks Adil many questions, alarm bells started ringing in his head but Adil chooses to ign ore the feeling that something might be wrong. Instead, Adil sweeps the feeling of misgiving away. The narrator says; 'Though Adil noticed in the father's tone something more than curiosity, he attributed this to the nature of the bedouin and their traditions.' (Hirschberg & Hirschberg 27). Adil makes the mistake of taking the interrogation lightly. He places complete trust in Salma and her father who have invited him to their home. It is his mistake. Adil only realizes too late that his trust is misplaced; 'In the same way as Adil had previously built the seven storey building that represented the seven months, each month containing twenty-eight days, till he would see Salma's face whenever it was full moon, he likewise sensed that this was the tribunal which had been set up to make an enquiry with him into the killing of the man whom he had one day come across on the tracks between the oases of Kharga and Farshout.' (Hirschberg & Hirschberg 27). Adil was too trusting to walk into the lion's lair of the bedouins and he was served his punishment. In the story of Gregory, the narrator and

Harmonics In Domestic Power Consumption Engineering Essay

Harmonics In Domestic Power Consumption Engineering Essay The objectives of this project are to design a model in Matlab/Simulink of a Domestic power system. The model represents a domestic power source and load that contains both linear and non-linear devices. It will be a time-based model which means these devices will be switched ON and OFF at various timings. Means of monitoring the voltages and currents responses are also added to this model and they are discussed in the results discussion part of this report. Finally, harmonic filters are added to the power system and their influence in reducing the harmonics content is observed. The approach taken for this project was to study the methods of simulation using Simulink and the examples related to Harmonics provided by this program. After that, a survey of Non-linear devices was conducted to observe the harmonics effects and to measure the values of the Total Harmonic Distortion (THD) and current amplitudes of the odd orders of the harmonics (i.e. 3rd, 5th, 7th harmonics and so on) of each device using a power quality meter. After completion of the survey, the measurements were added to the model and simulation of the power system is conducted. The results showedà ¢Ã¢â€š ¬Ã‚ ¦. Acknowledgements Table of Contents LIST OF TABLES LIST OF FIGURES CHAPTER 1 INTRODUCTION Background Power system quality has become a major concern for both the power supplier and the end-user especially with the various aspects of power quality disturbance. The impact of harmonics on the modern power systems in specific has become a serious issue to the electrical power utilities and to the costumers as it may cause huge economic losses. The impact of harmonic distortions on domestic power systems can be categorized to two categories: impact on the electrical power utilities of the power supplier and impact on the customer equipment and devices. From the power suppliers prospective, harmonic distortion may harm their major components like transformers, overhead transmission lines and cables. It might cause a reduction in the components lifetime and hence cause economic losses to the power supplier due to maintenance and reinstallation. This, in turn, will increase the system losses and as a result will reduce the efficiency of the power plant. From costumers prospective (residential area or domestic load in this case), a distorted domestic power system will affect the equipment and the devices that are being used. Harmonic distortion may cause them to overheat and reduces their lifetime. As a result, an increase in the electricity bills and economic losses to the customer may occur. The aim behind this project is to have a full understanding about non-linear domestic loads that exist in current residential power systems and their contribution to harmonic distortions. This project consists of a survey of measurements from a number of selected non-linear devices that may have an effect in the domestic power system in term of harmonics. After collecting these measurements, the distortion level will be compared to the international standards and a model will be designed in Simulink to represent the harmonics effect of these non-linear devices and then adding harmonic filters to mitigate their effect. Problem Definition The harmonics distortion produced by the non-linear devices in the domestic load can cause negative impacts on the domestic power system. Both the utilities and the customers are affected economically. Objectives Measuring and evaluating the harmonics that are produced by non-linear devices available in todays domestic loads than model them on Simulink. After that, further analysis and investigation for a solution to this harmonic distortion is to be done. Scope and Limitations This project will be focusing on the domestic loads that are connected to domestic power systems. It will only look into a specific power quality issue, which is harmonics and will disregard any other types of power quality disturbance. For this reason, the mitigation technique to reduce the total harmonic distortion will be considered is a passive harmonic filter. Report organization The final report consists of six chapters which are divided into sections and subsections for a better explanation of the contents of this report. Chapter one discusses about the background of the project and explains briefly the impacts of the harmonics on the utilities and the customers and the relationship between harmonics and the economic losses. It also defines the problem, the objectives and the scope and limitations to this project. Chapter two covers the literature review of research topic. It includes a proper definition of harmonics and lists their effects on power systems in terms of technical and economic losses. Moreover, the chapter gives information about harmonic sources and the available mitigation techniques that can be used to reduce the harmonics distortion. Chapter three is about the practical and experimental work that has been done. It will discuss how the measurements and the evaluation of the harmonic distortion have been done and the equipment that were used. It will also include a subsection about the modelling part of the project and the blocks that were used in Simulink. Chapter four will discuss the results acquired from the experimental work and briefly compare the harmonic distortion of the non-linear devices and the international standard. Chapter five is about conclusion and implications of the project. It includes a final discussion, a conclusion and recommendation for further work or issues to be pursued. CHAPTER 2 Literature Review 2.1 Introduction Power Quality disturbances can be defined as any power disturbance that will lead to voltage, current or frequency fluctuation that result in failure or misoperation of customer equipment. Power quality is considered to be a very important factor due to the fact that power is a part of our daily lives and any interruption or disturbance may cause into several problems such as data corruption, equipment damage, and data transmission errors and reduce equipment life. All these problems can result in huge economic losses to both the utility and the customers. There are several types of power quality disturbances as listed below [4]: Harmonics Transients Short-Duration Voltage Variations Long-Duration Voltage Variations Voltage Imbalance Waveform Distortion Voltage Fluctuation Power Frequency Variations This project will focus on one of the most important power quality disturbances which are harmonics. Harmonics are important to be analyzed as they occur in the industrial loads, residential loads and also in the utility. Analyzing harmonics will help to design a more stable system by applying the appropriate mitigation techniques that reduce harmonics. 2.2 What is Harmonics? A harmonic is a component of a periodic wave having a frequency that is an integral multiple of the fundamental power line frequency 50-60 Hz. Total harmonic distortion is the contribution of all harmonic frequency currents to the fundamental [5]. http://referencedesigner.com/books/si/images/fouriertransform.png 2.3 What is Inter-Harmonics? Inter-harmonics are additional frequencies which are not an integer of the fundamental frequency that can be observed between the harmonics of the power frequency voltage and current. It appears as discrete frequencies or as a wide-band spectrum and can be found in power systems of all voltage classes [1]. There are different sources of inter-harmonic waveform distortion such as static frequency converters, cyclo-converters, induction motors, arching devices and power line carrier signals. The corresponding effects of these inter-harmonics are affecting power line carrier signalling and induce visual flicker in display devices such as cathode ray tubes (CRTs) [1]. 2.4 Harmonic Effects Harmonics have many impacts on the electrical systems and equipment that it may cause overheating for some of the system components which will result in power losses that may decrease the life time of the components which means high economic losses for the utilities. Also if a consumer is having distorted waveforms, it will affect the life time of the equipment therefore again more losses for the consumer as well. Bottom line, harmonics impact is a chain reaction each problem will lead to many other problems [1]. Harmonics cause problems both on the supply system and within the insulation which can be summarized into the following [7]: Overloading of Neutrals: When the loads are not balanced, only the net out of balance current flows in the neutral. Installers (with the approval of the standards authorities) have taken advantage of this fact by installing half-sized neutral conductors. However, although the fundamental currents cancel out, the harmonic currents do not in fact those that are an odd multiple of three times the fundamental, the triple-N harmonics, add in the neutral [8]. 2. Effects on Transformers Transformers are affected in two ways by harmonics. Firstly, the eddy current losses increase at full load with the square of the harmonic number. This results in a much higher operating temperature and a shorter life time. Fortunately, few transformers are fully loaded; however the effect must be taken into account when selecting plant. The second concern is the triple-N harmonics. When reflecting back to a delta winding they are all in phase, which leads the triple-N harmonics to get trapped and circulate in the delta winding and does not get absorbed onto the supply. However, the non-triple-N harmonics can pass through the delta connection winding. The circulating current has to be taken into account when rating the transformer [4]. 3. Nuisance Tripping of Circuit Breakers Residual current circuit breakers (RCCB) operate by summing the current in the phase and neutral conductors if the result is not within the rated limit, disconnecting the power from the load. Nuisance tripping can occur in the presence of harmonics for two reasons. Firstly, the RCCB device may not sum the higher frequency components correctly and therefore trips. Secondly, the kind of equipment that generates harmonics also generates switching noise that must be filtered at the equipment power connection. The filters normally used for this purpose have a capacitor from line and neutral to ground, which might lead into current leakage to ground [4]. 4. Power Factor Correction Capacitors Power-factor correction (PFC) capacitors are provided in order to draw a current with a leasing phase angle in order to compensate for the lagging current that is drawn by the inductive loads such as induction motors. The impedance of the PFC capacitor reduces as the frequency increases, while the source impedance is generally inductive and increases when the frequency increases. As a result, the capacitor is likely to carry high harmonic currents which may lead to it getting damaged, unless it has been specifically designed to with stand that high amount of current [4]. 5. Skin Effect The skin effect is said to happen when the alternating current tends to flow on the outer surface of a conductor. Skin effect is normally ignored as its effect is minor at power supply frequencies. However at above about 350Hz which occurs at the seventh harmonic and above, the skin effect will become significant and will be taken into consideration. As it will be causing additional losses and heating [4]. 6. Induction Motors Harmonics may affect the induction motors in a way that the harmonics may induce a flux to the rotor in an opposite direction to the rotor rotation which will reduce the motor efficiency also harmonics may increase the eddy current in the rotor which therefore will increase heat dissipation [9]. 7. Zero-Crossing Noise Many electronic controllers detect the point at which the supply voltage crosses zero volts to determine when loads should be turned on. This is done because switching inductive loads at zero voltage does not generate transients which may lead into reducing electromagnetic interference and stress on the semiconductor switching devices [9]. 8. Harmonic Problems Affecting the Supply When a harmonic current is drawn from the supply it gives rise to a harmonic voltage drop proportional to the source impedance at the point of common coupling (PCC) and the current. Since the supply network is generally inductive, the source impedance is higher at higher frequencies. Of course, the voltage at the PCC is already distorted by the harmonic currents drawn by other consumers and by the distortion inherent in transformers, and each consumer makes an additional contribution [9]. 2.5 Sources of Harmonics Different non-linear loads produce different but identifiable harmonic spectra. This makes the task of recognizing the harmonics that are produced from those loads easier. Utilities and users of electric power have to become familiar with the signatures of different waveform distortions produced by specific harmonic sources. This will help us figure out better mitigation methods in order to reduce the harmonics produces from the source. This will reduce the harmonics penetration to the electrical power system. At the development of power electronic switching devices, harmonic current propagation was looked at from the perspective of design and operation of power apparatus devices with magnetic iron cores, like electric machines and transformers. At that time the main source of harmonics must have involved substation and customer transformers operating in the saturation region. Harmonics are the by-products of modern electronics. They occur frequently when there are large numbers of personal computers (single phase loads), uninterruptible power supplies(UPSs), variable frequency drives (AC and DC) or any electronic device using solid state power switching supplies to convert incoming AC to DC. Non-linear loads create harmonics by drawing current in abrupt short pulses, rather than in a smooth sinusoidal manner [1]. All variable frequency drives cause harmonics because of the nature of the frontend rectifier design. The 6-pulse rectifier is the standard power circuit elementary configuration for most pulse width modulated variable frequency drives with Diode Bridge rectifiers sold in the marketplace today. Harmonics are generated by non-linear loads, and can be divided into [1]: à ¢Ã¢â€š ¬Ã‚ ¢ Saturable Devices à ¢Ã¢â€š ¬Ã‚ ¢ Arcing Devices à ¢Ã¢â€š ¬Ã‚ ¢ Power Electronics 2.5.1 Saturable Devices Saturable devices are devices which operate under steady state conditions (constant voltage and current). Examples of saturable devices are: à ¢Ã¢â€š ¬Ã‚ ¢ Transformers à ¢Ã¢â€š ¬Ã‚ ¢ Rotating Machines 2.5.2 Arcing Devices Arcing devices are devices that consume high amount of current such as lighting ballasts, arc furnaces, welding machines and fluorescent lamps. à ¢Ã¢â€š ¬Ã‚ ¢ lighting ballasts Electronic lighting ballasts have become popular in recent years because of the overall improved efficiency. The light level can be maintained over an extended lifetime by feedback control of the running current and as result of changing the current it generates harmonics in the supply [1]. Small Uninterruptible Power Supplies (UPS) For high power units, UPS is used. The aim is to make the power supply load look like a resistive load so that the input current appears sinusoidal and in phase with the applied voltage as a result of that UPS is a source of harmonics [1]. Compact Fluorescent Lamps (CFL) The harmonic current spectrum is produced in CFL. These lamps are being widely used to replace filament bulbs in domestic properties and especially in hotels where serious harmonic problems are suddenly becoming common [1]. 2.5.3 Power Electronics Devices Switched mode power supplies (SMPS) Majority of companies use modem electronic units like SMPS. The advantage to the equipment manufacturer is that the size, cost and weight is significantly reduced and the power unit can be made in almost any required form factor. But its disadvantage is that, rather than drawing continuous current from the supply, the power supply unit draws pulses of current which contain large amounts of third and higher harmonics and significant high frequency components [1]. Figure 2.2 Switched Mode Power Supplies (DC-to-DC Converter) 6-Pulse Thyrister Rectifier Variable speed controllers, UPS units and DC converters in general are usually based on the three-phase bridge. The six pulse bridge produces harmonics as 6n (- or +) 1. As we increase Pulse Bridge, harmonics will be less [11]. 2.6 Mitigation Techniques There are many ways to reduce harmonics, ranging from variable frequency drive designs to the addition of auxiliary equipment. The primary methods used today to reduce harmonics are: à ¢Ã¢â€š ¬Ã‚ ¢ 12-Pulse Converter In this configuration, the front end of the bridge rectifier circuit uses twelve diodes instead of six. The advantages are the elimination of the 5th and 7th harmonics to a higher order where the 11th and 13th become the predominate harmonics. This will minimize the magnitude of harmonics, but will not eliminate them. The disadvantages are cost and construction, which also requires either a Delta-Delta and Delta-Wye transformer, Zig-Zag transformer or an autotransformer to accomplish the 30 ° phase shifting necessary for proper operation. This configuration also affects the overall drive system efficiency rating because of the voltage drop associated with the transformer configuration requirement. Transformers Transformers have reactance and resistance which makes it represent the majority of the impedance found in lines feeding non-linear loads. Reactive impedance increases directly with frequency, naturally attenuating harmonics by reducing available current at higher frequencies. This technique is commonly used in reducing the current distortion of electric motor drives in industrial applications. Delta-Delta connected transformers for some drives and Delta-Wye connected transformers for the remaining drives are used in order to trap the triple-n harmonics. This will lead into current distortion reduction [7]. Line Reactors This method consists of connecting a line reactance in series with the harmonic source at which the reactance will reduce the harmonic current. However, the line reactance method has different advantages and disadvantages as shown in the Table 2.l[12]. Advantages Disadvantages Low Cost Harmonics reduction is insignificant Available in different values Dynamic characteristics depend on the line capacity Small power losses At very low load conditions it may damage the line due to high harmonic currents Table 2.1 Advantages and disadvantages of Line Reactors The amount of harmonic that can be reduced is a function of the impendence of the line reactor the higher the line impendence the higher the reduction in harmonics. Active Filters Active harmonic filters uses power electronic devices in order produce harmonic current components that cancel the harmonic current components that are produced by the nonlinear loads. The active harmonic filter is configured based on a pulse width modulated (PWM) voltage source inverter that interfaces to the system through a system interface filter. The active filter configuration that is shown in Figure 2.6 is referred as a parallel active filter as the filter is connected in parallel with the nonlinear load that is compensated. Figure 2.6 show the concept of the current cancelation so that the current being supplied from the source is sinusoidal. The voltage source inverter is used in the active filter in order to control the harmonics. This inverter uses dc capacitors as the supply and can switch at high frequencies to generate a signal that can cancel the harmonics produced by the non-linear loads. The voltage distortion is reduced because the harmonic currents that flow through the source impedance are reduced [13]. http://ars.els-cdn.com/content/image/1-s2.0-S0019057811001133-gr1.jpg Passive Filters Passive filters consist of capacitor, inductor and a resistor connected in parallel to a nonlinear load. Passive filters will provide a low impedance path for the harmonic current therefore will inject them to ground. Passive filters can be tuned to absorb one type of harmonic current or several types as shown in the Figure 2.7 [14]. Figure 2.7 Passive Tuned Filters: (a) Single Tuned (b) Double Tuned Another important feature of the passive filters is that they can improve the power factor since they have a capacitance in their construction. Moreover, filters can be specified according to the connection type into two main groups, the series connection and parallel. The filters power losses depends on the material used so the lower the losses the higher the cost of the filter so after all its a trade of between the power losses and the filter cost [15]. In conclusion, many techniques by which harmonics can be mitigated from the system but always there are some advantages and disadvantages for each technology which makes it appropriate for some applications and not for others. Moreover, the decision of using which mitigation technique depends mostly on the cost, reliability and power losses. Always important to keep in mind that theoretical calculation and assumptions for the type/size of mitigation technique does not always match with the practical findings due to some voltage disturbance and phase unbalancing. 2.7 Harmonic Evaluation and Measurements 2.7.1 Introduction Evaluating harmonic system is a very important step in the analysis and design process. In order to evaluate the harmonics sources we should follow some standards that are set by IEEE as they have specified some guidelines and limits that we should follow. Following those guidelines will be helpful during measurements and understanding the devices used. 2.7.2 Harmonics Limits There are many standards which have been set by many organizations (national/international) in order to improve the quality of service provided and to protect the customers from all different effect of disturbances that may occurs in electrical systems. For this project we will discuss the limits specified by the Institute of Electrical and Electronics Engineers. 2.7.3 Institute of Electrical and Electronics Engineers (IEEE) According to IEEE 519-1992 standards the total voltage distortion and the total current distortion limits should be within the specified limits as shown in Table 3.1 and Table [2]: Table 3.1 Total Voltage Distortion Limits According to IEEE 519-1992 Table 2.7 Total Current Distortion Limits According to IEEE 519-1992 SCR is the ratio of the maximum short circuit current to the maximum fundamental frequency load current at the point of common coupling (PCC)[]. 2.7.4 Harmonics Evaluation Harmonic currents produced by nonlinear loads can interact with the utility power supply. This interaction often gives a rise to voltage and current harmonic distortion observed in many places in the system. Therefore, to limit both voltage and current harmonic distortion, as seen in the limits set by the IEEE standard 519-1992 in order to limit the harmonic current injection from the end users to make the harmonic voltage levels on the overall power system acceptable [8]. The two most common used indices measuring the harmonic waveform are: à ¢Ã¢â€š ¬Ã‚ ¢ Total Harmonic Distortion (THD) à ¢Ã¢â€š ¬Ã‚ ¢ Total Demand Distortion (TDD) Since there are two parties involved in limiting the total harmonic distortion which are divided between the utility and the customers, the evaluation is divided into two parts which are: à ¢Ã¢â€š ¬Ã‚ ¢ Measurements of the currents that are being injected by the loads à ¢Ã¢â€š ¬Ã‚ ¢ Calculations of the frequency response of the system impedance The total harmonic distortion (THD) is a measure of the effective value of the harmonic components of a distorted waveform relative to the fundamental. In order to calculate the total harmonic distortion for the voltage or current Equation (1) or (2) are used [1]: (1) (2) The total demand distortion (TDD) is expressed in terms of the maximum demand load current. TDD can be calculated using Equation (3) [1]: (3) In computing the short circuit level at the point of common coupling the normal system condition that will result in minimum short circuit level will be taken into consideration as it causes the most severe impact to the system. The short circuit current can be calculated using Equation (3.3) [8]: Where MVA and kV represent the three-phase short-circuit capacity in megavolt amperes and the line-to-line voltage at the point of common coupling in kV, respectively. The load current should be evaluated in order to determine the short circuit ratio Equation (3.4) can be used to calculate the load current [8]: 3.6 How to Evaluate Compliance Harmonic currents produced by nonlinear loads can interact adversely with the utility supply system. The interaction often gives rise to voltage harmonic distortion and current harmonic distortion observed in many places in the power system. Therefore, it is required to identify the point of common coupling (PCC) in order to have a more accurate measurement and evaluation. For industrial and commercial end users, the PCC is usually at the primary side of a service transformer that supplies the facility as shown in figures 3.1 and 3.2.

Selfless Service Definition Essay -- Expository Essays

Selfless Service When one sees the word selfless service, he/she literally sees the words self and less, followed by service. Self refers to an individual (in this case, it refers to one’s own interests) and less indicates a lack of, or without. Service can be a synonym of the word volunteering or duty. Therefore, the term selfless service must literally mean the lack of the pursuit of one’s own interests for the betterment of others. There is no measurement of selfless service. No matter what the scenario or who is involved, everyone who is involved benefits from one’s selfless acts. The one who shows selflessness may benefit by receiving a â€Å"thank you,† or even just a good feeling of helping others. Of course, the ones who receive the selfless acts benefit from obvious reasons. Selfless service can be shown by anyone and everyone, including a soldier putting his/her life on the line to save a fallen comrade, a husband and father protecting and spending time wit h his wife and children, someone donating his/her time by volunteering as a tutor or with the American Red Cross or some other goodwill charity, and the teamwork of two or more athletes. Those four examples provide different scales in which selfless service can be displayed. Selfless service can be displayed in regards to one’s nation/military, one’s family, one’s community, and any team sport. The U.S. Army’s definition of selfless service is â€Å"to put the welfare of the nation, the Army, and your subordinates before your own† (â€Å"Selfless Service,† GoArmy.com). The Army consists of teams, in which those teams form a larger size unit, etc. If a team fails, the unit fails. One reason that a team may fail could have something to do with selfishness, which is of cour... ...less service by displaying humble teamwork in an effort to win as a team. Works Cited -Famous Quotes at QuoteDB - Interactive Database of Famous Quotations. 16 Feb. 2009 -Medtrng.com. 11 Feb. 2009 . -Quotesea.com. 16 Feb. 2009 . - â€Å"Selfless Service.† GoArmy.com. 11 Feb. 2009 . -â€Å"Selfless Service.† Wikipedia, the free encyclopedia. 11 Feb. 2009 . - â€Å"Selfless Service and Service to Others.† Our Ultimate Reality. 16 Feb. 2009 . -ThinkExist.com Quotations. 16 Feb. 2009 .

Heuristics and Biased Essay

Daniel Kahneman along side of Amos Tversky revolutionized research on human judgment. They conceptualized the idea of the â€Å"heuristics and biases† program – that judgment under uncertainty Often rests on a limited number of simplifying heuristics rather than extensive algorithmic processing. Gigerenzer criticized Kehneman and Tverskys research stating that humans are capable of processing more complex algorithms than what Kehneman and Tversky were giving homage to. Thus a debate of what the cognitive capacity is and the deviations between normative models and actual human reasoning has been called into question by casting doubt on the appropriateness of the normative models used to evaluate performance, a form of the â€Å"reject-the-norm† strategy. It has been noted the Panglossians, exclusively used the reject the-norm-application strategy to eliminate gaps between descriptive models of performance and normative models. When this type of critique is employed, the normative model that is suggested as a substitute for the one traditionally used in the heuristics and biases literature is one that coincides perfectly with the descriptive model of the subjects’ performance, thus preserving a view of human reasoning and rationale as ideal. Gigerenzer urged that the cognitively capacity is in fact more than this. Gigerenzer urged that there is sufficient evidence for the existence of two types of processing in Human reasoning, decision making, and social cognition. One type fast, automatic, effortless, and non-conscious, the other slow, controlled, effortful, and conscious, which may deliver different and sometimes conflicting results. More recently, some cognitive psychologists have proposed ambitious theories of cognitive architecture, according to which humans possess two distinct reasoning systems, almost two Minds, known as System 1 and System 2. A composite characterization of the two systems runs as follows. System 1thinking, one relies heavily on a number of heuristics (cognitive maneuvers), key situational characteristics, readily associated ideas, and vivid memories to arrive quickly and confidently at a judgment. System 1: thinking is particularly helpful in familiar situations when time is short and immediate action is required. System 2 is more recent, and its processes are slow, controlled, effortful, conscious, serial, shaped by culture and formal tuition, demanding of working Memory and related to general intelligence. It is reasoning based on what we have learned through careful analysis, evaluation, explanation, and elf-correction. This is the system which values intellectual honesty, analytically anticipating what happens next, maturity of judgment, fair-mindedness, elimination of biases, and truth-seeking In addition, it is often claimed that the two systems employ different procedures and serve different goals, with System 1 being highly contextualized, associative, heuristic, and directed to goals that serve the reproductive interests of our genes, and System 2 being decontextualized, rule-governed, analytic, and serving our goals as individuals. This is a very strong hypothesis, and theorists are already recognizing that it requires substantial qualification and complication. Gigerenzer is not denying that normatives appropriate for simple case judgments exist, but rather expostulates that the existence and the nature of such normative have been imperiously assumed by the heuristics and biases literature. Gigerenzer argues that some of the biases identified by Kahneman and Tversky are unstable, in the sense that for example in some cases their magnitude can be considerably reduced by asking questions in terms of frequencies rather than in terms of probabilities. Second, on a methodological level, Gigerenzer argues that, because Kahneman and Tversky’s heuristics are formulated by means of vague, theoretical terms like representativeness, the appeal to these heuristics as generators of biases has limited explanatory power; Gigerenzer advocates instead an increasing emphasis on investigating the cognitive processes that underlie judgment under uncertainty. Third, on a normative level, Gigerenzer argues that it may be inappropriate to characterize some of the biases identified by Kahneman and Tversky as â€Å"errors† or â€Å"fallacies†. Gigerenzer’s reason for objecting to the use of the term â€Å"bias† Gigerenzer argues that Kahneman and Tversky may be comparing the performance of the participants in their experiments with incorrect normatives. Many critics have insisted that in fact it is Kahneman & Tversky, not their subjects, who have failed to grasp the logic of the problem. Or that if a â€Å"fallacy† is involved; it is probably more attributable to the researchers than to the subjects. When ordinary people reject the answers given by normative theories, they may do so out of ignorance and lack of expertise, or they may be signaling the fact that the normative theory is inadequate.

Grade Inquiry Essay

Project context Innovation have made possible for the operations of the computer easy enough in processing records system such as, creation of data, storing, filing and retrieval of data. This Online Grade inquiry with subject evaluation and SMS notification is a process whereby a department head input the grades of the students who are enrolled to the said department and evaluates what subjects should they be taking after they passed their current enrolled subject for them to take their proceeding subject to the next semester after the input of data to the system. The system sends also the grades to the students via SMS every end of the trinal exam who is enrolled to the said department before that they will give first the data to the registrar in order to send the data to the students because the registrar clarify first the data because one of the foremost responsibilities of the registrar office is to keep the student’s grades data secured for their records and purposes. The head of the sa id department may now easily encode the data to the system and give the standing records to their students without a consuming a lot of time and gives convenient kind of servicing to the student. The system basically keeps all the records of the students about their grades and class subjects and it will determine if a particular student passed or fail the subject and it also display announcements like meetings and dates of signing of clearances etc. Purpose and Description Our project focuses mainly on keep in track of the students grade and subject and also sending the grade of the student via SMS who are enrolled to the said department. This system on the other hand can display important announcement like meetings and news. By this, the head of the department can easily gives the grades of a student by just encoding the grades of the students into the system. And also if the head of the department has special announcements to make to the said department, the students can easily read the announcement made by the dean even if they are not in the school. Statement of the problem General: The manual submission and distribution of the grades in the department (BSBA) or in the registrar (NDKC). The time consuming of subject evaluation at the registrar’s office. Specific:Â  The students need to go directly to their respective department or at the school registrar to inquire their grades. The long processes of inquiry of grades are inconvenient, tiresome, and some instances are time consuming. Objectives General: To develop an online grade encoding, inquiry and evaluation system. To develop a system that will lessen the registrar’s tasks in encoding of grades. Specific: To develop a system that can able to send grades automatically via SMS. To develop a system that is convenient and less effort to inquire the grades of the student. Scope and Limitations The proposed system is concerned in sending SMS about the student’s grades and displays the evaluation of a student and announcement. This covers only the grade data; their class subjects to evaluate; and announcements to post and only limited to the following: 1. Send SMS about students Grade; 2. Displays evaluation of the student and the announcement of the dean; 3. Control the records of the students; 4. Update the records; 5. Organize new coming data; Scope The request of the grades can be done through any network of mobile phones/ cellular phones. The head of the department only has the authority to the system. The head of the department can encode grades of the students through online. The system automatically back-up the records being encoded. The device use in the system is for inquiry only. The head of the department can print the summary of grades and also the subjects taken by the students. Limitations It cannot be used for conversation. The system has no capability of handling delayed messages. If the responsible of inputting grades submitted a wrong grade of a student, the system is not reliable of human error. The system cannot accept landline number in registration for the students as their contact number. The system can be accessed by internet connection only. Significance of the study: This study was made to find out the use of online – based system that will lessen the time for transaction, accommodation and convenience of releasing the grades of the students. The college of Business of Administration which is one of the top departments of NDKC with high population which is fit to this project for us to cope/manage all the records about their student grades class subject evaluation and announcement using the said system. Through this project the said department can easily organize all the records of the students and keep in track in its database. The department would have a website that can easily use and can interact between the department and with their students. The system provides accessibility to the head of the department only and can update the grades and give evaluation to the subjects taken to the certain student. Students can receive their grades via SMS, view their evaluation subject and also can see what their head of the department announcement s. The said department will be assured of an accurate, high performance and a high level of security using the system. One benefit is that the students will know the announcements of their college dean and receive or to know their grades anywhere, as long as they are connected to the internet.