Multivariate Multilevel Modeling

Multivariate Multilevel Modeling Literature Review This chapter tying up the various similar studies related to modeling responses multivariately in a multilevel frame work. As a start, this chapter begins by laying out the recent history of univariate techniques for analyzing categorical data in a multilevel context. Then it gradually presents the literature available on fitting multivariate multilevel models for categorical and continuous data. More over this chapter reviews the evidence for imputing missing values for partially observed multivariate multilevel data sets. The Nature of Multivariate Multilevel models A multivariate multilevel model can be considered as a collection of multiple dependent variables in a hierarchical nature. Though the multivariate analysis increases the complexity in a multilevel context, it is an essential tool which facilitates to carry out a single test of the joint effects of some explanatory variables on several dependent variables (Snijders Bosker (2000). These models have the power of increasing the construct validity of the analysis for complex concepts in the real world. Consider a study on school effectiveness which can be measured on three different output variables math achievement, reading proficiency and well-being at school. These data are collected on students those who are clustered within schools by implying a hierarchical nature. Although it is certainly possible to handle three outcomes separately, it is unable to show the overall picture about school effectiveness. Therefore multivariate analysis would be more preferable in these types of scen arios since it has the capability of decreasing the type 1 error and increasing the statistical power (Maeyer, Rymenans, Petegem and Bergh) (Draft). Hierarchical natures of multivariate models are not like as the univariate response models. Let us focus on above example; it implies a two level multivariate model. But in reality it has three levels. In this case, the measurements are the level 1 units, the students the level 2 units and the schools the level three units. Importance of Multivariate Multilevel Modeling Multivariate multilevel data structures may itself present a greater complexity as it leads to focus the multilevel effects together with the multivariate context. Therefore the traditional statistical techniques would fail to face these kinds of areas since it can decrease the statistical efficiency by producing overestimated standard errors. On the other hand violation of independence assumption may cause to under estimate the standard errors of regression coefficients. Therefore multivariate multilevel approaches play an important role to get rid of these kinds of situations by allowing variation at different levels to be estimated. Furthermore Goldstein (1999) has shown that clustering provides accurate standard errors, confidence intervals and significance tests. Some amount of articles have been published on multilevel modeling based on a single response context. Multivariate multilevel concept comes into the field of statistics during the past few years. When people want to identify the effect of set of explanatory variables on a set of dependent variables and by considering these effects separately on response variables, then if it shows a considerable difference among those effects then it can be handled only by means of a multivariate analysis (Snijders Bosker, 2000). Software for Multivariate Multilevel Modeling In the past decades, due to the unavailability of the software for fitting multivariate multilevel data some researchers tend to use manual methods such as EM Algorithm (Kang et al., 1991). As a result of developing the technical environment, the software such as STATA, SAS and S plus are emerged in to the Statistical field by providing facilitates to handle the multilevel data. But none of those packages have a capability of fitting multivariate multilevel data. However there is evidence in the literature that nonlinear multivariate multilevel model can be fitted using packages such as GLLAMM (Rabe-Hesketh, Pickles and Skrondal, 2001) and aML (Lillard and Panis, 2000). But it was not flexible to handle this software. Therefore MlwiN software which has become the under development since late 1980’s was modified at the University of Bristol in UK in order to fulfill that requirement. However, the use of MlwiN for fitting multivariate multilevel models has been challenged by Goldstein, Carpenter and Browne (2014) who concluded that MlwiN was useful if only when fitting the model without imputing for the missing values. However REALCOM software was then came into the field of Statistics and provided the flexibility to impute the missing values in the MLwiN environment. MLwiN is a modified version of DOS MLn program which uses a command driven interface. MLwiN provides flexibility to fitting very large and complex models using both frequentist and Bayesian estimation along with the missing value imputation in a user friendly interface. Some particular advanced features which are not available in the other packages are included in this software. Univariate Multilevel Modeling vs. Multivariate Multilevel Modeling In general, data are often collected on multiple correlated outcomes. One major theoretical issue that has dominated the field for many years is modeling the association between risk factors and each outcome in a separate model. It may cause to statistically inefficient since it ignores outcome correlations and common predictor effects (Oman, Kamal and Ambler) (unpublished) Therefore most of the researches tend to include all related outcomes in a single regression model within a multivariate outcome framework rather than univariate. Recently investigators have examined the comparison between Univariate and Multivariate outcomes and they have proven that Multivariate models would be preferable than several univariate models. According to the Griffiths, Brown and Smith (2004), they conducted a study to compare univariate and multivariate multilevel models for repeated measures of use of antenatal care in Uttar Pradesh, India. In here, they examined many factors which may have a relationship to the mother’s decision to use ante-natal care services for a particular pregnancy. For that they compared Univariate multilevel logistic regression model vs. Multivariate multilevel logistic regression model. However as a result of fitting univariate models, model assumptions became violated and couldn’t get stable parameter estimates. Therefore they preferred the multivariate context rather than the univariate context after performing the analysis. Generalized Cochran Mantel Haenzel Tests for Checking Association of Multilevel Categorical Data. The history of arising the concepts related to Generalized Cochran Mantel Haenzel was streaming to the late 1950’s. Cochran (1958), one of a great Statistician has firstly introduced a test to identify the independence of multiple 2 Ãâ€" 2 tables by extending the general chi-square test for independence of a single 2-way table. In here, the each table consists of one or two additional variables for higher levels to detect the multilevel nature. The test statistic is based on the row totals of each table. The assumption behind is that the cell counts have binomial distribution. As an extension to Cochran’s work, Mantel and Haenzel (1959) extended the Cochran’s test statistic for both row and column totals by assuming the cell counts of each table follows a hypergeommetric distribution. Since Cochran Mantel Hanzel (CMH) statistic has a major limitation on binary data, Landis et al (1978) generalized this test into handle more than two levels. However there is a major drawback of the Generalized Cochran Mantel Haenzel (GCMH) test. This test was unable to handle clustered correlated categorical data. Liang (1985) was proposed a test statistic for get rid of this problem. However that test statistic itself had major problems and it was fail to use. As development of the statistics field, a need for a test statistic capable of handling correlated data and variables with higher levels arouse. Zhang and Boos (1995) coming in to the field and introduced three test statistics TEL TP and TU as a solution to the above problems. However among these three test statistics TP and TU are preferred to TEL since these two use the individual subjects as the primary sampling units while TEL use the strata as the primary sampling unit (De Silva and Sooriyarachchi, 2012). Furthermore, by a simulation study TP shows better performance than TE by maintaining its error values even when the strata are small and it uses the pooled estimators for variance. Therefore it provides a guideline to select TP as the most suitable statistic to perform this study. De Silva and Sooriyarachchi (2012) developed a R program to carry out this test. Missing Value Imputation in Multivariate Multilevel Framework The problem of having missing values is often arising in real world datasets. However it contains little or no information about the missing data mechanism (MDM). Therefore modeling incomplete data is a very difficult task and may provide bias results. Therefore this major problem address to a need of a proper mechanism to check the missingness. As a solution to that, Rubin (1976) presented three possible ways of arising misingness. These are classified as Missing At Random (MAR), Missing Completely At Random (MCAR) and Missing Not At Random (MNAR). According to the Sterne et. Al (2009), missing value imputation is necessary under the assumption of missing at random. However, it can also be done under the case missing complete at random. On nowadays most statistical packages have the capability of identifying the type of missingness. After identifying the type of missingness, the missing value imputation comes into the field and it requires a statistical package to perform this. Since the missing value imputation in a hierarchical nature is little bit more advanced and it cannot be done using usual statistical packages such as SPSS, SAS and R etc. Therefore Carpenter et. al (2009), developed the REALCOM software to perform this task. However latter version of REALCOM was not deal with multilevel data in a multivariate context. Therefore the macros related to perform this task was recently developed by the Bristol University team in order to facilitate under this case. Estimation Procedure The estimation procedures for multilevel modeling are starting late 1980’s. However For parameter estimation using Maximum Likelihood Method, an iterative procedure called EM algorithm was used by early statisticians (Raudenbush, Rowan and Kang, 1991). Later on the program HLM was developed to perform this algorithm. The most operational procedures for estimating multivariate multilevel models in the presence of Normal responses are Iterative Generalized Least Squares (IGLS), Reweighted IGLS (RIGLS) and Marginal Quasi Likelihood (MQL) while for discrete responses are MQL and Penalized Quasi Likelihood (PQL). According to Rasbash, Steele, Browne and Goldstein (2004) all of these methods are implemented in MLwiN along with including first order or second order Taylor Series expansions. However since these methods are likelihood based frequentist methods they tend to overestimate the precision. Therefore more recently the methods which are implemented in a Bayesian framework using Marcov Chain Monte Carlo methods (Brooks, 1998) also used for parameter estimation which allows capability to use informative prior distributions. These MCMC estimates executed in MLwiN provides consistent estimates though they require a large number of simulations to control of having highly correlated chains. Previous researches conducted using Univariate and Multivariate Multilevel Models Univariate multilevel logit models Before take a look at to the literature on multivariate multilevel analysis, the literature of univariate multilevel analysis is also be necessary to concerned since this thesis is based on some univariate multilevel models prior to fit multivariate multilevel models. In the past decades, many social Scientists used to apply multilevel models for binay data. Therefore it is very important to review how they have implemented their work with less technology. As a aim of that, Guo and Zhao (2000) was able to do a review of the methodologies, hypothesis testing and hierarchical nature of the data involve of past literature. Also they conducted two examples for justify their results. First of all they made a comparison between estimates obtained from MQL and PQL methods which was implemented by MLn and the GLIMMIX method implemented by SAS by using examples. They have shown that the differences in PQL 1 and PQL 2 are small when fitting binary logistic models. Furthermore, they have shown that PQL- 1 and PQL-2 and GLIMMIX are probable to be satisfactory for most of the past studies undertaken in social sciences. Noortgate, Boeck and Meulders (2003) uses multilevel binary logit models for the purpose of analyzing Item Response Theory (IRT) models. For that they carried out an assessment of the nine achievement targets for reading comprehension of students in primary schools in Belgium. They performed a multilevel analyses using the cross-classified logistic multilevel models and used the GLIMMIX macro from SAS, as well as the MLwiN software. However they found that there were some convergence problems arisen by using PQL methods in MLwiN. Therefore they used SAS to carryout analysis. Furthermore they have shown that the cross-classification multilevel logistic model is a very flexible to handle IRT data and the parameters can still be estimated even with the presence of unbalanced data. Multivariate Multilevel Models In the past two decades a very few of researches have sought to fit the multivariate multilevel models to the real world scenarios. Among those also all most all the researches trying to focus basically in educational sectors as well as socio economic sectors. None of them were able to focus these into the medical scenarios. However lack of multivariate multilevel analysis which presents in the field of health and medical sciences this chapter consists of the literatures of multivariate multilevel models in other fields. According to the previous studies of education, Xin Ma (2001) examined the association between the academic achievements and the background of students in Canada by considering three levels of interest. For that the three level Hierarchical Linear Model (HLM) was developed in order to achieve his goals. This work allows him to draw the conclusions that both students and schools were differentially successful in different subject areas and it was more obvious among students than among schools. However the success of this study is based on some strong assumptions about the priors of student’s cognitive skills. Exclusive of the field of education Raudenbush, Johnson and Sampson (2003) carried out a study in Chicago to determine the criminal behavior at person level as well as at neighborhood level with respect to some personal characteristics. For this purpose they use a Rasch model with random effects by assuming conditional independence along with the additives. Moreover, Yang, Goldstein, Browne and Woodhouse (2002) developed a multivariate multilevel analysis of analyzing examination results via a series of models of increasing complexity. They used examination results of two mathematics examinations in England in 1997 and analyzed them at individual and institutional level with respect to some students features. By starting from a simpler model of multivariate normality without considering the institutional random effects, they gradually increased the complexity of the model by adding institutional levels together with the multivariate responses. When closely looked at, there work shows that the choice of subject is strongly associated with the performance. Along with this growth of applications of multivariate multilevel models, researches may tend to apply those in to the other fields such as Forestry etc. Hall and Clutter (2004) presented a study regarding modeling the growth and yield in forestry based on the slash pine in U.S.A. In their work, they developed a methodology to fit nonlinear mixed effect model in a multivariate multilevel frame work in order to identify the effects of the several plot-level timber quantity characteristics for the yield of timber volume. In addition to that they also developed a methodology to produce predictions and prediction intervals from those models. Then by using their developments they have predicted timber growth and yield at the plot individual and population level. Grilli and Rampichini (2003) carried out a study to model ordinal response variables according to the students rating data which were obtained from a survey of course quality carried out by the University of Florence in 2000-2001 academic years. For that they developed an alternative specification to the multivariate multilevel probit ordinal response models by relying on the fact that responses may be viewed as an additional dummy bottom level variable. However they not yet assess the efficiency of that method since they were not implemented it using standard software. When considering the evidences of the recent applications of these models the literature shows that Goldstein and Kounali (2009) recently conducted a study on child hood growth with respect to the collection of growth measurements and adult characteristics. For that they extended the latent normal model for multilevel data with mixed response types to the ordinal categorical responses with having multiple categories for covariates. Since data consists of counts they gradually developed the model by starting a model with assuming a Poison distribution. However since the data are not follow exactly a Poisson distribution they treated the counts as an ordered categories to get rid of that problem. Frank, Cerda and Rendon (2007) did a study to identify whether the residential location have an impact to the health risk behaviors of Latino immigrants as they are increasing substantially in every year. For that they used a Multivariate Multilevel Rasch model for the data obtained by Los Angelis family and neighborhood survey based on two indices of health risk behaviors along with their use of drugs and participation for risk based activities. They starting this attempt by modeling the behavior of adolescents as a function of the characteristics related to both individual and neighborhood .According to the study they found that there is an association between increased health risk behaviors with the above country average levels of Latinos and poverty particularly for those who born in U.S.A. Another application of multivariate multilevel models was carried out Subramanian, Kim and Kawachi (2005) in U.S.A. Their main aim was to identify the individual and community level factors for the health and happiness of individuals. For that they performed a multivariate multilevel regression analysis on the data obtained by a survey which was held on 2000. Their findings reflect that those who have poor health and unhappiness have a high relationship with the individual level covariates By looking at the available literature, it can be seen that there are some amount of studies conducted on education and social sciences in other countries but none of the studies conducted regarding health and medical sciences. Therefore it is essential to perform a study by analyzing the mortality rates of some killing diseases which are spread in worldwide to understand risk factors and patterns associated with these diseases in order to provide better insights about the disease to the public as well as to the responsibly policy makers.

Contemporary issues on mobility and work spaces

Oxford Encyclopedia of Economic History. Retrieved 24 February 2011 . – also Jump up A A Legal Bridge Spanning 100 Years: From the Gold Mines of El Dorado to the ‘Golden' Startups of Silicon Valley By Gregory Grooms, 2010. Assignment 1, mobility – Threaten Darkish First let me explain how this essays goes which I tough it would look and sound better if the definition and samples come first and then after that and also in between I refer them to interior design and our roles and use as one.I'll start with the definition of the word mobility to get to know this term and see it's difference from the other use of mobility as in the new technology and mobile APS for workplaces. Therefore â€Å"Mobility' indicates a worker's ability to physically move around freely in he workplace to accomplish work. Mobility for work can be assisted with items such as a wheel chair, crutches, canes, a desk near the door, a scooter to ride between distant buildings, and a shuttle bus.M obility also refers to a worker's ability to take advantage of various Job opportunities ( I will write more on this issue below), including the ability to relocate, move to a superior Job position, commute a particular distance to work daily, or change positions due to family and civic responsibilities. Some impediments to the mobility of labor include personal hindrances such as geographical location and ability to move, physical and mental ability, and prior Job experiences. Social/legal hindrances to mobility include a lack of educational opportunities, family responsibilities, and various laws.A frequent use of the word, mobility, occurs when organizations use the term to define the upward mobility of employees. An employee with upward mobility has the appropriate mix of needed qualities and characteristics including experience, knowledge, skills, education, cultural fit, and availability. An employee with upward mobility potential is ready for promotional opportunities*. Now a t this point I going to write further more about the mobility of employees and various Job opportunities to see what that points to exactly and how that is related to mobility.Employee mobility is an issue that has taken on a whole new meaning as more and more businesses have gone global. Employees today are commonly asked to take assignments in company locations outside their home country. These kinds of opportunities are seen as Contemporary Issues in Interior Architecture- Fall 2014 2 benefits by many employees who enjoy experiencing new cultures and the multi- cultural exposure. Managing employee mobility is important though, because without the right training and planning, employees moving to foreign countries will not be prepared to meet the challenges such moves present.Your company does not want to find itself faced with loss of productivity, or worse, loss of its best managers because of lack of planning. Being prepared to address the issues related to employee mobility sho uld be included in the company's strategic planning. Quality of living in this matter can be an issue if a company frequently transfer employees within the country or outside the country. Either way there are concerns which should be addressed in these compensation and benefits packages.For example, in the US, a manager transferred from a small town in Texas to a large northeastern city will be faced with many of the same issues as an employee transferred from the US to Canada and that is a very simple and the most easiest transfer in contrast with moving to India or china, a completely different culture. These concerns or issues include cultural and compensation differences. These differences become more pronounced when the company re-assigns employees from a developed country to a third world country.But it is really a matter of degree. Making sure that the staff are well prepared for these types of moves will insure the transition is smooth and they remain productive. After all t he reason managers are transferred is in order to better utilize their talents and skills within the company**. Here I can say our role as an interior designers may help with these issues but with prior researching, planning, somehow rearranging their working spaces even from their own country to their destinations.So that they can familiarize themselves and got to know those areas better prior going there to make them arm proof and repaper Just in case. Many transfers involve more than the staff also. The managers and workers in general have families who are as much a part of the move as the company employees. It's important for the company to recognize the needs of the employee's family also. Unless the staff feel as if their family will also benefit from the transfer without Jeopardizing their safety or welfare, company transfers will meet a lot of resistance.In these cases also our role as interior designers can come to great use by even designing and making their homes look lik e the one in future after move, better said aka and redesign them as person by hurt so they would not feel alienated. Now here are some instances of companies and how they help these employees related with this mobility matter. For instance the Whichever Workforce Mobility*** helps clients optimize their mobile workforce by delivering innovative solutions that make it faster, easier and more cost effective to deploy key talent and transfer critical skills anywhere in the world.Our expertise in Contemporary Issues in Interior Architecture- Fall 2014 3 relocation and assignment management ensures that our clients' mobility programs advance their business and workforce strategies. They deliver sustained customer value through unique service and engagement initiatives, including: – Trusted Partner – Next Practices – Fans – Balanced Scorecard Here again we as designers can be creative about those mentioned above. Even by being faster, easier and more cost effe ctive.By faster that can be as helping deploy critical talent at the speed of business by motivating them through Just by one look but by a great look. Because opportunity won't wait. By easier that can be as to Just open communication, transparency, mutual trust and boundless innovation. And by ore-cost effective that can be vast global resources and in-house expertise to control our clients' program costs which we can be ahead of it by being innovative or creative in these fields to somehow more economic but more fashionable.Also there is other term as labor mobility, which Labor mobility or worker mobility is the geographical and occupational movement of workers. Worker mobility is best gauged by the lack of impediments to such mobility. Impediments to mobility are easily divided into two distinct classes with one being personal and the other being systemic. Personal impediments include physical location, and physical and mental ability. The systemic impediments include education al opportunities as well as various laws and political contrivances and even barriers and hurdles arising from historical happenstance.Increasing and maintaining a high level of labor mobility allows a more efficient allocation of resources. Labor mobility has proven to be a forceful driver of innovations. There I also another International Labor Mobility. Which International labor mobility is the movement of workers between countries. It is an example of an international factor movement. The movement of laborers is based on a difference in resources between countries. According to economists, Over time the migration of labor should have an equalizing effect on wages, with workers in the same industries garnering the same wage.

Principles

Airdrop is the act of extracting cargo out of the back of the airplane while the airplane is flying. The loaders section consists of 30 session ready airman. In order to accomplish this mission every member of the airlift squadron must remain current on all training items. Every six months there are a number of training events that must take place for every member. Without accomplishing each event, the member becomes â€Å"not mission ready† and this, in turn effects the entire squadron.In order to keep everyone mission ready, the chief loaders, Scams Ballard, schedules weekly flying for everyone in the unit. Each member can accomplish a limited number of tasks per flight, so in order to accomplish the entire list of acquirement, a member must fly nearly once every two weeks. This unit, being an Air National Guard unit has its limitations as most members have outside full-time jobs and have limited availability. This makes scheduling difficult for Scams Ballard because it is h is job to ensure everyone is mission ready.Managers abilities (Planning, Organizing, Directing, Controlling) â€Å"Planning is the logical thinking through goals and making the decision as to what needs to be accomplished in order to reach the section's, department's or organization's objectives. Organization is a matter of appointing individuals to assignments or responsibilities that blend together to develop one purpose, to accomplish the goals. It is supervising, or leading workers to accomplish the goals of the organization. The process that guarantees plans are being implemented properly is the controlling process (Trident University, n,d). Scams Ballard is a great manager and leader. He oversees 30 members of our unit in every aspect of the workplace. He delegates certain areas to other supervisors in the unit; like medical readiness, the seasoning training program, safety, and other areas. Scams Ballard plans the schedule for our nit so that everyone remains mission ready a nd readily deployable. Deploying overseas to help other forces is the most important aspect of our job. Scams Ballard also ensures that members who have been flying for a while help out the newest members.The squadron has yearly flight evaluations that must be planned and scheduled so that our unit can ensure everyone knows how to do their job the right way. Scams Ballard and 2 other high ranking members of our unit act as flight evaluators. If during a flight they feel that a member isn't being safe or doing their job correctly, he can immediately disqualify that member from flying. If a member fails his/her evaluation they must fly with an instructor and start the process of becoming re-qualified over a long period.Scams Ballard is also in charge of assigning annual training days for each member. In the Air National Guard, each member is required to have 15 days of active duty training (part of the one weekend a month and two weeks a year slogan). He notifies everyone that they ca n schedule those annual training days and everyone submits their requested days. He is in charge of ensuring everyone shows up on time and is available to accomplish squadron tasks. Department Issues There are a few issues in the department but the biggest area of concern is keeping everyone mission ready.Performing in-flight tasks is at the discretion of the member, as they are required to submit availability sheets to Scams Ballard, so that he knows when people are available. For example, if airdrops are only performed on Tuesdays and Thursdays and the member is only available on Wednesdays, it will be difficult to keep that person up to date. There are other areas, like computer based training, that everyone in the Air Force has to accomplish, but these are additional items on top of our light requirements that Scams Ballard must keep track of.A second issue is the availability of aircraft to perform required tasks. The airplanes at the squadron are nearly 20 years Old, and are s tarting to wear down. This means more time in the maintenance shop being fixed and repaired. The more time an airplane spends in the hangar, the less time members of the unit get to fly it. Principles This work was made in order to explain the principles of economics that is handled in society or a country. People, companies, the government and society must face a common problem: managing scarce resources. Scarcity means that society has limited resources and therefore can not produce all the goods and services that people want to have (unlimited wants). To address the shortage must choose between different alternatives available (go to the stadium or a party, buy a coat or a suit) . The economy is the social science that studies the choices that individuals, genuineness, government and society made to face shortages.It is based on ten principles grouped as follows. Objectives What kind of questions about the economy? How individuals make decisions? How do the Individuals? How does the economy as a whole? ECONOMIC PRINCIPLES The principles of economics are based on ten principles grouped as follows: Group 1: Principles that govern how Individuals make decisions. Else they want. M aking decisions is choosing between two objectives. If a student studies, it is leaving a few hours of sleep. If a parent buys food, you are not buying someone else's reduce.When they decide to spend an additional weight in a well, are having a weight less to spend on other goods or services. Individuals are grouped to form companies which also face these dilemmas. Example, buy more weapons for national defense or increase public spending to improve wages or offer better education. In developing an economic policy, society is faced with the dilemma between efficiency and equity, ‘e, thinning the most of scarce resources and the equitable sharing of the benefits of these resources among its members. 2 The cost of something is what is forgone to obtain it.As individuals face tradeoffs, making decisions should compare the costs and benefits of different alternatives. While determining a benefit is relatively obvious, appears equal to the event cost. Consider for example the decis ion to study (in college or high school). The benefits of this decision can be summarized as intellectual enrichment and a better employment opportunities after graduation. Among the costs have the monetary cost of tuition, fees, food, transportation, photocopying, books and materials that will address over the years of study, but in addition we must consider the use of time devoted to study.The valuation of this time corresponds to the higher salary that would have earned by working instead of studying. This is what is known as opportunity cost alternative higher value that is left to do to get something (in other words, what you give up is the cost of what we get). 3 Rational people think at the margin. Manama describes the desire for a rational person to buy a good as if it were based on the marginal surplus that person would bring an extra element. Manama points out the difference in value between water and diamonds.A marginal increase in the water supply of a person rarely invo lves a significant cost to that person. On the Usually the decisions that individuals make are not only two aspects, there is a range of possibilities. So a student does not choose between studying for a contest O hours or 24 hours a day, choose an intermediate time. These small additional adjustments to a plan of action are known as marginal changes. Individuals and companies can make better decisions thinking at the margin. A decision is rational only if the marginal benefit involved is greater than the marginal cost.Suppose that an airline must decide how much to charge passengers for a flight between Santiago and Miami. Suppose the round trip on a plane with a capacity of 200 seats is $ 900,000. In this case, the average cost per seat is $ 4,500. One might be tempted in this case to conclude that the airline should not sell tickets at prices below $ 4. 500. Sin But the airline can increase profits marginally thinking. Suppose the flight is about to leave with 20 empty seats, and suppose there is a passenger waiting to take the plane and is willing to pay $ 3,000 for it.Should the airline sell you a ticket? Of course you do. If the plane has empty seats, the cost of adding a passenger is negligible: although the average cost is $ 4,500, the marginal cost is simply the food that the extra passenger will consume. So, while the passenger was willing to pay more than the marginal cost, selling a ticket is profitable. 4 People respond to incentives. Individuals decide comparing costs and benefits, but their behavior may change if the costs and benefits change.Example, if you raise the price of a kilo of apples this becomes an incentive to buy pears. If the government maintains the fuel tax is an incentive to increase purchases of cheap cars. Group 2: Principles relating to the way in which individuals interact. Trade can improve the welfare of each individual. This is because there specialization. A family may decide to move in the field and build your home, gro w food, raise cattle, produce wool and leather to make clothing, etc. But not everyone has the skills to perform all those tasks which makes the action is inefficient.That's why there is trade (between individuals, businesses, countries) where each actor specializes in what it does best and this eventually leads to there being a greater quantity and variety of goods and services at lower cost as their production is efficient (so there Fats) 6. Arrests are a good way to organize economic activity. Currently the market economy has shifted to centralized economies, IEEE those in which the central government planning models determined what occurred, who did it, how much and who consumed him.The market economy involves the decisions of millions of individuals and businesses. People decide what to buy with their incomes and firms decide what to produce. These individuals and firms interacting in markets for goods and services where prices and self-interest guide their decisions. As stated in the above principle, the markets are good regulators of economic activity, over at times the state should intervene to promote efficiency and equity. This happens when â€Å"market failures† which are situations in which the market alone does not efficiently allocate resources are presented.Externalities and market power are two examples of market failures. Externalities are consequences that the action of an individual or company has on the welfare of another individual or company. Example is pollution; a company in the production process pollutes not try to decrease unless the State applies fines for polluting. Market power, meanwhile, is defined as the ability of an agent or a small group of them to significantly influence market prices. This is the case of monopolies, oligopolies, monopoly (ANSI, Arafat) and oligopolies (supermarkets who buy vegetables to farmers).Group 3: principles of how the economy works as a whole. 8 The standard of living of a country depends on its ability to produce goods and services. Productivity levels, IEEE, the amount of goods and services produced for each hour of work are key determinant of living standards of the countries. Thus, a country with high productivity will have more products and its people have more clothes, more DOD, more cars, etc. , which makes your standard of living is high compared to countries with low productivity where the supply of products is lower.This leads us to note that the growth rate of productivity of a country determines the growth rate of its average income. Obviously that productivity is not the only determinant of quality of life, but the most important. Others are public policies that foster education, technology acquisition, training of employees, etc. 9 Prices rise when the government prints too much money. A government decides to increase the amount of money when it is not able to solve TTS spending to revenues (taxes, patents, etc. , the problem is that this leads to inflati on, IEEE the increase in the general level of prices in the economy . A high and prolonged inflation imposes some costs on society, so keep at a low level is a goal of those responsible for the economic policy of a government (and worldwide). 10 Society faces a short-run tradeoff between inflation and unemployment. The inflation problem could be solved if the government reduces the amount of money in the economy, but the solution is not really as simple as closely (inversely) with inflation is unemployment.This is reflected in the Phillips curve: If the overspent decides to actually decrease the amount of money in order to reduce inflation, a general fall in prices (more lengthen the short term), resulting in a drop in occurs corporate income, if this happens, companies will seek to decrease their costs financial management conclusion In conclusion this work we did with the learning or understanding of economic principles which are governed in a country that are 10 principles to con sider in a given economy, we will see a summary of each of them, to know . People face tradeoffs. To have something, we usually sacrifice something else, either time, money or other sources. 2 The Cost of Something is what you give up to get. Everything has a cost and a benefit. Our decisions will compare these costs and benefits between the alternatives. Here comes the issue of opportunity cost, which basically refers to what you give up to get something else. 3 Rational People Think at the Margin. People make decisions by comparing costs and benefits in terms of margin.This involves knowing the benefits and costs of each decision alternative. 4 The People Respond to Incentives. Marginal changes in costs or benefits motivate people to respond. Then decisions will sake an alternative when the marginal benefit is greater than marginal cost. 5 The Exchange can make everyone better. People earn for their ability to exchange something for something else. This exchange allows people can specialize in what it does best. Markets are Usually a Good Way To Organize Economic Activity. In a market economy there is a relationship between the families and businesses. On the one hand families decide what they will buy and who will work for this and on the other hand businesses decide what will be produced and who will hire for this. 7 Governments sometimes can improve economic performance. When markets fail, the government can intervene to promote efficiency and equity.

Memory Management Challenges And Alogrithm For Traditional...

Memory Management Challenges And Alogrithm for Traditional Memory Mapping Abstract:- According to the need of real time systems many algorithm have been use to allocate memory efficiently Real time system may crash if they do not get memory on priority or request memory loss can also be prevented by using memory allocation algorithm our goal is to focus on traditional memory management algorithm according to their efficiency and their response time to recognize the problem and limitation and challenges that occurs problem which may reduce the performance of real time system. This research paper will help you in determining the real time memory management algorithm technique the latency rate and problem. Introduction:- Efficient Memory management is performed by modern operating system and still working for efficient memory allocation for application because the main stuff is to provide required memory block for application with minimum memory loss as compared to the traditional memory allocation which is known as â€Å"Memory Fragmentation† which keep the records of those block that are free and those that are allocated to tasks. For the purpose memory allocation designs are being used for example: Static Memory Allocation, Dynamic Memory Allocation describe in Fig: 1 Fig:1 {Memory Allocation} Real Time System support both techniques and both of them distributes memory in different way in Static Memory Allocation, memory is allocated at compile time it has efficient