Analysis Of A Letter I My Son By James Baldwin

Racism in North America, although a social construct, is almost a natural instinct. Humans are not born with race but rather are raised to see people a certain way which is a quality that stays with them throughout the rest of their lives. â€Å"Race discrimination involves treating someone unfavorably because of the individuals certain race or because of personal characteristics associated with race such as hair texture, skin color, or certain facial features† (Equal Employment Opportunity Commission, para. 1). Any country located on the Asian continent like China and India are naturally considered â€Å"Asian†. The fact being Middle Eastern countries Saudi Arabia and Iraq are also Asian. In ‘A letter to my nephew’, James Baldwin emphasises how poorly the black culture is being treated. Stressing how, specifically, his people are treated so poorly only based on their skin color which takes away from one s culture and tradition involving the takeover of rac ism, minimizing the culture. What most fail to realize is that Asians, are racially assaulted by numerous individuals and this goes unpunished in the U.S and must be acknowledged. History of racism against Asians is rarely discussed. The Angell Treaty of 1880 modified the US-China Burlingame Treaty of 1868, accepting the suspension of Chinese immigrants in the U.S. Followed by â€Å"The Chinese Exclusion Act which was a United States federal law signed by President Chester A. Arthur on May 6, 1882. It was the most significantShow MoreRelatedAnalysis Of The Book Between The World And Me Essay1855 Words   |  8 Pagesstandpoint to analyze today’s version of racism. Coates strays away from his usual journalist works to a more deeper and personal view. His book is devoted to his fifteen-year-old son, Samori, and provides him with guidance through the struggle of racism; all while letting Samori fend for himself. Coates’ lets his son know all this through history, and heritage; of his own and of America’s. Ta-Nehisi Coates is a journalist, blogger, and memoirist incorporates historical comprehension to exhibit America’sRead MoreProject Managment Case Studies214937 Words   |  860 PagesSTUDIES, SECOND EDITION - PROJECT MANAGEMENT CASE STUDIES, SECOND EDITION HAROLD KERZNER, Ph.D. Division of Business Administration Baldwin-Wallace College Berea, Ohio John Wiley Sons, Inc. This book is printed on acid-free paper. @ Copyright O 2006 by John Wiley Sons, Inc. All rights reserved. Published by John Wiley Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmittedRead MoreProject on Risk Management46558 Words   |  187 PagesACKNOWLEDGEMENT Expressing gratitude is not just an exercise of formality rather doing so evokes the memories of my association with my mentors and mates. I thank Chairman Prof. J. D. Agarwal and Director Aman Agarwal for allowing me to carry out this project. I wish to express my sincere gratitude to my corporate guide, Mr. Ashok Sharma for guiding me to understand the concepts those were not clear to me. I learnt a lot from his professional sknowledge. SUBODH AGARWAL 4108163163 Management of BusinessRead MoreManagement Course: Mba−10 General Management215330 Words   |  862 PagesContents Feigenbaum−Feigenbaum †¢ The Power of Management Capital 1. New Management for Business Growth in a Demanding Economy 1 1 Text Jones−George †¢ Contemporary Management, Fourth Edition I. Management 17 17 2. The Evolution of Management Thought Hughes−Ginnett−Curphy †¢ Leadership, Fifth Edition I. Leadership is a Process, Not a Position 51 51 70 1. Leadership is Everyone’s Business 2. Interaction between the Leader, the Followers the Situation Cohen †¢ Effective Behavior in OrganizationsRead MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 PagesLibrary of Congress Cataloging-in-Publication Data Robbins, Stephen P. Organizational behavior / Stephen P. Robbins, Timothy A. Judge. — 15th ed. p. cm. Includes indexes. ISBN-13: 978-0-13-283487-2 ISBN-10: 0-13-283487-1 1. Organizational behavior. I. Judge, Tim. II. Title. HD58.7.R62 2012 658.3—dc23 2011038674 10 9 8 7 6 5 4 3 2 1 ISBN 10: 0-13-283487-1 ISBN 13: 978-0-13-283487-2 Brief Contents Preface xxii 1 2 Introduction 1 What Is Organizational Behavior? 3 The Individual Read MoreVarian Solution153645 Words   |  615 PagesB 25 C D 30 35 E 10 F 18 G 15 H 5 (a) Plot the market demand curve in the following graph. (Hint: When the market price is equal to some consumer i’s reservation price, there will be two diï ¬â‚¬erent quantities of apartments demanded, since consumer i will be indiï ¬â‚¬erent between having or not having an apartment.) 2 THE MARKET (Ch. 1) Price 60 50 40 30 20 10 0 1 2 3 4 5 6 7 8 Apartments (b) Suppose the supply of apartments is ï ¬ xed at 5 units. In this case thereRead MoreIntangible Asset Accounting and Accounting Policy Selection in the Football Industry85391 Words   |  342 Pagesfinancial reporting. ACKNOWLEDGEMENTS May I thank and acknowledge the following in producing this thesis; Andrew Thomas for supervision; the Professional Footballers Association, The Football Trust, the Deloitte Touche Football Industry Team and the football clubs themselves for the provision of information; Timothy Isherwood for data collection, James Cessford, Douglas Leonard, Stephen Thorpe, Alexander Burfitt, Matthew Brough, Ms Blurton, and my family for support, help and inspiration.

Criminal Justice Process Essay example - 1094 Words

When a crime is committed against another person, then justice must be served to those who committed the crime. In some cases the crimes involve sexual attacks on grown adults while some offenses are against minors. In these examples the underling connection is the committed crimes of sexual abuse or sexual assault on adults and minors. When these crimes are brought before the justice system they are processed and the convicted are given a sentence to carry out but sometimes those sentences may not provide efficient time to produce the required outcome of correcting the individual or may be determined that there is no fixing the convicted disorder. The United States Supreme Court decision to hold a mentally ill, sexually dangerous†¦show more content†¦These two statics prove that those convict of sexually assault have a high probability for committing the same acts upon new victims and if an inmate does not show that any sort of treatment has worked then they will victim ize more innocent people. Since sexual offenders are often categorized has having an illness or underlining problem than the treatment must have time to take effect. The treatment for sexual offenders is done in a three principal approach which is cognitive behavioral approach, psycho-educational approach, and pharmacological approach. The cognitive behavioral approach gives emphasis on altering the habits of the offended relating toward sexual offending and â€Å"deviant patterns of arousal†. (CSOM) This means altering the daily habits of the offender which may be everything they had known previously to incarceration. The second principal of psycho-educational focuses on altering the offender’s state of mind toward their victims and attempts to instill the understanding of how they inflicted harm with their actions. With psychology there is never a set time on how long a set goal will be reached. Times vary between individuals and can sometime never reach their desired outcome. In conjunction with those previous principals the offenders are also treated under the pharmacologicalShow MoreRelatedInvestigation Of The Criminal Justice Process947 Words   |  4 PagesThe criminal justice process begins with a report of violation of the law by a citizen or witnessed by a police officer first hand. Then after it is investigated where the police officer is to come to the area or scene of the incident to determine the extent and nature of the crime committed. Where sometimes an arrest is made on the scene of the incident and statements of the witnesses or evidence are taken to obtain evidence of the crime. In some cases there is a preliminary investigation whereRead MoreThe Criminal Justice Process For A Felony Offender1608 Words   |  7 Pages The criminal justice process for a felony offender can be a lengthy one depending on the crime committed and the amount of evidence in the case. The criminal justice process would not work without the help of law enforcement, the judicial and corrections departments. Society demands justice, while the offender fights maintain their rights as well. All parties involved in a case in the criminal justice system have positive and negative things to say, but there are some improvements which I thinkRead MoreEssay about Criminal Justice Process772 Words   |  4 PagesMica Massey Colorado Technical University Online Professor: Ivan Kaminsky Introduction to Criminal Justice June 11, 2013 Phase 3 Discussion Board Assignment Criminal Justice Process Juveniles are not extended the right to a jury of their peers. What is the most significant reason why this right is not extended to juveniles? Please explain in detail why you chose that particular reason. I do not think that there is only one significant reason as to why juveniles are not extended theRead MoreCriminal Justice System and Process Essay1347 Words   |  6 Pagesas Criminal Law (Law Library, 2011). Criminal law is also termed as Penal law, it comprises of rules as well as statutes that have been written by the Congress and the state legislators who deal with criminal activities (petty crimes, felonies or misdemeanors) that have a direct or indirect harm to the general public and is accompanied by penalties of these crimes, (Morrison, 2008). Criminal law is enforced by the government. Criminal law has sub-sections that include: Substantive Criminal LawRead MoreCriminal Justice Process Ensures Individuals Rights1439 Words   |  6 PagesIntroduction A criminal justice process is normally followed to ensure an individual’s rights are not abused. According to Moak and Carlson (3), the criminal justice process aims to ensure that relevant fact-finding is conducted in an effort to establish the truth. The criminal justice procedure needs to be done in accordance or by not being in contrary to an individual’s right as stipulated in the Fourth, Fifth, Sixth, Eighth and Fourteen amendments of the U.S. Constitution. Moak and Carlson (4)Read MoreSentencing Is The Final Stage Of The Criminal Justice Process874 Words   |  4 PagesSentencing is essentially the final stage of the criminal justice process, aside from the appeals process. It is a dual decision-making process that consists of two significant stages. The first stage reflects the decision to grant incarceration or probation upon the accused, while the second stage involves determining the length of a sentence (Neubauer Fradella, 2011). As this discussion focuse s on the second stage of the sentencing process, it is important to understand key stakeholders involvedRead MoreCriminal Justice: Concept, Process, System, and Agencies Essay668 Words   |  3 PagesCriminal Justice: Concept, Process, System, and Agencies Helen Jordan-Seals CRJS 1001-12 – Contemporary Criminal Justice System July 29, 2012 The Criminal Justice System goes as far back as the days of Jesus. There were Soldiers who acted like policeman, the tribune which was the court system, and Caesar, Herod and even Pontius Pilate stood as judge. The prison system was that of dark caves and dungeons. As we journey to the twenty-first century, nothing has genuinely changed. Read MoreCriminal Justice System The Criminal Justice System is made up of several different process law900 Words   |  4 PagesCriminal Justice System The Criminal Justice System is made up of several different process law enforcement, judiciary, and corrections this system is where the accused individual are tried and punished for the crime they are charged with. The depiction of criminal justice system in throughout each process (police, courts, and correctional) has become ubiquitous on television today. Shows that give a visual of the arresting and investigation process (law enforcement) are the televisions showsRead MoreThe Criminal Justice System For Crime Control And Due Process1466 Words   |  6 PagesThe American criminal justice systems have over time faced the need of a justice scheme that incorporated both the crime control and due process. There have been constant debates regarding the superiority of each model. The crime control system is based on curbing criminal activities by focusing mainly on the victim of the crime rather than the rights of the accused criminal. This meant that as long as one claimed breach of rights by another the system would push to punish accused without consideringRead MoreCriminal Justice Process for a Felony1790 Words   |  7 PagesCriminal justice process for a felony Introduction The processing of a crime and the criminal case can be terribly confusing, especially for those unfamiliar with the criminal justice system scheme. Once a person commits a crime, it is the obligation of the public to enlighten the police. That is where the journey through the justice system of a country or state begins for the offender. There are certain minor variations in the justice process of different states; nonetheless, most of the procedures

Transfer Functions Free Essays

string(141) " Summing point Takeoff point Block Transfer function \+_ The above figure shows the way the various items in block diagrams are represented\." ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ TRANSFER FUNCTIONS AND BLOCK DIAGRAMS 1. Introduction 2. Transfer Function of Linear Time-Invariant (LTI) Systems 3. We will write a custom essay sample on Transfer Functions or any similar topic only for you Order Now Block Diagrams 4. Multiple Inputs 5. Transfer Functions with MATLAB 6. Time Response Analysis with MATLAB 1. Introduction An important step in the analysis and design of control systems is the mathematical modelling of the controlled process. There are a number of mathematical representations to describe a controlled process: Differential equations: You have learned this before. Transfer function: It is defined as the ratio of the Laplace transform of the output variable to the Laplace transform of the input variable, with all zero initial conditions. Block diagram: It is used to represent all types of systems. It can be used, together with transfer functions, to describe the cause and effect relationships throughout the system. State-space-representation: You will study this in an advanced Control Systems Design course. 1. 1. Linear Time-Variant and Linear Time-Invariant Systems Definition 1: A time-variable differential equation is a differential equation with one or more of its coefficients are functions of time, t. For example, the differential equation: d 2 y( t ) t2 + y( t ) = u ( t ) dt 2 (where u and y are dependent variables) is time-variable since the term t2d2y/dt2 depends explicitly on t through the coefficient t2. An example of a time-varying system is a spacecraft system which the mass of spacecraft changes during flight due to fuel consumption. Definition 2: A time-invariant differential equation is a differential equation in which none of its coefficients depend on the independent time variable, t. For example, the differential equation: d 2 y( t ) dy( t ) m +b + y( t ) = u ( t ) 2 dt dt where the coefficients m and b are constants, is time-invariant since the equation depends only implicitly on t through the dependent variables y and u and their derivatives. 1 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Dynamic systems that are described by linear, constant-coefficient, differential equations are called linear time-invariant (LTI) systems. 2. Transfer Function of Linear Time-Invariant (LTI) Systems The transfer function of a linear, time-invariant system is defined as the ratio of the Laplace (driving function) U(s) = transform of the output (response function), Y(s) = {y(t)}, to the Laplace transform of the input {u(t)}, under the assumption that all initial conditions are zero. u(t) System differential equation y(t) Taking the Laplace transform with zero initial conditions, U(s) Transfer function: System transfer function G (s) = Y(s) Y(s) U(s) A dynamic system can be described by the following time-invariant differential equation: an d n y( t ) d n ? 1 y( t ) dy( t ) + a n ? 1 + L + a1 + a 0 y( t ) n ? 1 dt dt dt d m u(t) d m ? 1 u ( t ) du ( t ) = bm + b m ? 1 + L + b1 + b 0 u(t) m m ? 1 dt dt dt Taking the Laplace transform and considering zero initial conditions we have: (a n ) ( ) s n + a n ? 1s n ? 1 + L + a 1s + a 0 Y(s) = b m s m + b m ? 1s m ? 1 + L + b1s + b 0 U(s) The transfer function between u(t) and y(t) is given by: Y(s) b m s m + b m ? 1s m ? 1 + L + b1s + b 0 M (s) = = G (s) = U(s) N(s) a n s n + a n ? 1s n ? 1 + L + a 1s + a 0 where G(s) = M(s)/N(s) is the transfer function of the system; the roots of N(s) are called poles of the system and the roots of M(s) are called zeros of the system. By setting the denominator function to zero, we obtain what is referred to as the characteristic equation: ansn + an-1sn-1 + + a1s + a0 = 0 We shall see later that the stability of linear, SISO systems is completely governed by the roots of the characteristic equation. 2 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ A transfer function has the following properties: †¢ The transfer function is defined only for a linear time-invariant system. It is not defined for nonlinear systems. The transfer function between a pair of input and output variables is the ratio of the Laplace transform of the output to the Laplace transform of the input. †¢ All initial conditions of the system are set to zero. †¢ The transfer function is independent of the input of the system. To derive the transfer function of a system, we use the following procedures: 1. Develop the differential equation f or the system by using the physical laws, e. g. Newton’s laws and Kirchhoff’s laws. 2. Take the Laplace transform of the differential equation under the zero initial conditions. 3. Take the ratio of the output Y(s) to the input U(s). This ratio is the transfer function. Example: Consider the following RC circuit. 1) Find the transfer function of the network, Vo(s)/Vi(s). 2) Find the response vo(t) for a unit-step input, i. e. ?0 t 0 v i (t) = ? ?1 t ? 0 Solution: 3 R vi(t) C vo(t) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: Consider the LCR electrical network shown in the figure below. Find the transfer function G(s) = Vo(s)/Vi(s). L R i(t) vi(t) vo(t) C Exercise: Find the time response of vo(t) of the above system for R = 2. 5? , C = 0. 5F, L=0. 5H and ? 0 t 0 . v i (t) = ? ?2 t ? 0 4 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: In the mechanical system shown in the figure, m is the mass, k is the spring constant, b is the friction constant, u(t) is an external applied force and y(t) is the resulting displacement. y(t) k m u(t) b 1) Find the differential equation of the system 2) Find the transfer function between the input U(s) and the output Y(s). 5 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 3. Block Diagrams A block diagram of a system is a pictorial representation of the functions performed by each component and of the flow of signals. The block diagram gives an overview of the system. Block diagram items: Summing point Takeoff point Block Transfer function +_ The above figure shows the way the various items in block diagrams are represented. You read "Transfer Functions" in category "Essay examples" Arrows are used to represent the directions of signal flow. A summing point is where signals are algebraically added together. The takeoff point is similar to the electrical circuit takeoff point. The block is usually drawn with its transfer funciton written inside it. We will use the following terminology for block diagrams throughout this course: R(s) = reference input (command) Y(s) = output (controlled variable) U(s) = input (actuating signal) E(s) = error signal F(s) = feedback signal G(s) = forward path transfer function H(s) = feedback transfer fucntion R(s) Y(s) E(s) G(s) +_ F(s) H(s) Single block: U(s) Y(s) Y(s) = G(s)U(s) G(s) U(s) is the input to the block, Y(s) is the output of the block and G(s) is the transfer function of the block. Series connection: U(s) X(s) G1(s) Y(s) G2(s) 6 Y(s) = G1(s)G2(s)U(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Parallel connection (feed forward): G1(s) + U(s) Y(s) Y(s) = [G1(s) + G2(s)]U(s) + G2(s) Negative feedback system (closed-loop system): R(s) E(s) +_ The closed loop transfer function: Y(s) G(s) Y(s) G(s) = R(s) 1 + G(s) Exercise: Find the closed-loop transfer function for the following block diagram: R(s) Y(s) E(s) G(s) +_ F(s) H(s) 7 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) _______________________________________________________________________________ Exercise: A control system has a forward path of two elements with transfer functions K and 1/(s+1) as shown. If the feedback path has a transfer function s, what is the transfer function of the closed loop system. R(s) +_ Y(s) 1 s +1 K s Moving a summing point ahead of a block: R(s) Y(s) G(s) + R(s) Y(s) +  ± G(s)  ± F(s) 1/G(s) F(s) Y(s) = G(s)R(s)  ± F(s) Moving a summing point beyond a block: R(s) Y(s) + R(s) G(s) Y(s) G(s)  ± +  ± F(s) G(s) F(s) Y(s) = G(s)[R(s)  ± F(s)] Moving a takeoff point ahead of a block: R(s) Y(s) R(s) Y(s) G(s) G(s) Y(s) Y(s) G(s) Y(s) = G(s)R(s) 8 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Moving a takeoff point beyond a block: R(s) Y(s) R(s) Y(s) G(s) G(s) R(s) R(s) 1/G(s) Y(s) = G(s)R(s) Moving a takeoff point ahead of a summing point: R(s) Y(s) + Y(s)  ± F(s) R(s)  ± F(s) +  ± Y(s) + Y(s) Y(s) = R(s)  ± F(s) Moving a takeoff point beyond a summing point: R(s) R(s) Y(s) + Y(s) +  ±  ± F(s)  ± R(s) F(s) R(s) + Y(s) = R(s)  ± F(s) Exercise: Reduce the following block diagram and determine the transfer function. R(s) + _ + G1(s) G2(s) G3(s) _ Y(s) + + H1(s) G4(s) H2(s) 9 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: Reduce the following block diagram and determine the transfer function. H1 + R(s) +_ + G H2 10 Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 4. Multiple Inputs Control systems often have more than one input. For example, there can be the input signal indicating the required value of the controlled variable and also an input or inputs due to disturbances which affect the system. The procedure to obtain the relationship between the inputs and the output for such systems is: 1. 2. 3. 4. Set all inputs except one equal to zero Determine the output signal due to this one non-zero input Repeat the above steps for each of the remaining inputs in turn The total output of the system is the algebraic sum (superposition) of the outputs due to each of the inputs. Example: Find the output Y(s) of the block diagram in the figure below. D(s) R(s) +_ G1(s) + + H(s) Solution: 11 Y(s) G2(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) _______________________________________________________________________________ Exercise: Determine the output Y(s) of the following system. D1(s) R(s) +_ G1(s) + + Y(s) G2(s) H1(s) + + D2(s) 12 H2(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 5. Transfer Functions with MATLAB A transfer function of a linear time-invariant (LTI) system can be entered into MATLAB using the command tf(num,den) where num and den are row vectors containing, respectively, the coefficients of the numerator and denominator polynomials of the transfer function. For example, the transfer function: G (s) = 3s + 1 s + 3s + 2 2 can be entered into MATLAB by typing the following on the command line: num = [3 1]; den = [1 3 2]; G = tf(num,den) The output on the MATLAB command window would be: Transfer function: 3s+1 ————s^2 + 3 s + 2 Once the various transfer functions have been entered, you can combine them together using arithmetic operations such as addition and multiplication to evaluate the transfer function of a cascaded system. The following table lists the most common systems connections and the corresponding MATLAB commands to implement them. In the following, SYS refers to the transfer function of a system, i. e. SYS = Y(s)/R(s). System MATLAB command Series connection: R(s) Y(s) G1 G2 SYS = G1*G2 or SYS = series(G1,G2) Parallel connection: G1 + R(s) SYS = G1  ± G2 or SYS = parallel(G1, ±G2) Y(s)  ± G2 Negative feedback connection: R(s) Y(s) +_ G(s) SYS = feedback(G,H) H(s) 13 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ R(s) Y(s) +_ G1 G2 H Example: Evaluate the transfer function of the feedback system shown in the figure above using MATLAB where G1(s) = 4, G2(s) = 1/(s+2) and H(s) = 5s. Solution: Type the following in the MATLAB command line: G1 = tf([0 4],[0 1]); G2 = tf([0 1],[1 2]); H = tf([5 0],[0 1]); SYS = feedback(G1*G2,H) This produces the following output on the command window (check this result): Transfer function: 4 ——-21 s + 2 Exercise: Compute the closed-loop transfer function of the following system using MATLAB. R(s) +_ 1 s +1 14 s+2 s+3 Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. Time Response Analysis with MATLAB After entering the transfer function of a LTI system, we can compute and plot the time response of this system due to different input stimuli in MATLAB. In particular, we will consider the step response, the impulse response, the ramp response, and responses to other simple inputs. 6. 1. Step response To plot the unit-step response of the LTI system SYS=tf(num,den) in MATLAB, we use the command step(SYS). We can also enter the row vectors of the numerator and denominator coefficients of the transfer function directly into the step function: step(num,den). Example: Plot the unit-step response of the following system in MATLAB: Y (s) 2s + 10 =2 R (s) s + 5s + 4 Solution: Step Response 2. 5 num = [0 2 10]; den = [1 5 4]; SYS = tf(num,den); step(SYS) Amplitude 2 or directly: step(num,den) 1. 5 1 MATLAB will then produce the following plot on the screen. Confirm this plot yourself. 0. 5 0 0 1 2 3 Time (sec. ) 4 5 For a step input of magnitude other than unity, for example K, simply multiply the transfer function SYS by the constant K by typing step(K*SYS). For example, to plot the response due to a step input of magnitude 5, we type step(5*SYS). Notice in the previous example that that time axis was scaled automatically by MATLAB. You can specify a different time range for evaluating the output response. This is done by first defining the required time range by typing: t = 0:0. 1:10; % Time axis from 0 sec to 10 sec in steps of 0. 1 sec and then introducing this time range in the step function as follows: step(SYS,t) % Plot the step response for the given time range, t This produces the following plot for the same example above. 15 6 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) _______________________________________________________________________________ Step Response 2. 5 Amplitude 2 1. 5 1 0. 5 0 0 2 4 6 8 10 Time (sec. ) You can also use the step function to plot the step responses of multiple LTI systems SYS1, SYS2, †¦ etc. on a single figure in MATLAB by typing: step(SYS1,SYS2,†¦ ) 6. 2. Impulse response The unit-impulse response of a control system SYS=tf(num,den) may be plotted in MATLAB u sing the function impulse(SYS). Example: Plot the unit-impulse response of the following system in MATLAB: Y(s) 5 = R (s) 2s + 10 Solution: Impulse Response um = [0 5]; den = [2 10]; SYS = tf(num,den); impulse(SYS) 2. 5 2 impulse(num,den) Amplitude or directly 1. 5 1 This will produce the following output on the screen. Is that what you would expect? 0. 5 0 0 0. 2 0. 4 0. 6 Time (sec. ) 16 0. 8 1 1. 2 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. 3. Ramp response There is no ramp command in MATLAB. To obtain the unit ramp response of the transfer function G(s): multiply G(s) by 1/s, and use the resulting function in the step command. The step command will further multiply the transfer function by 1/s to make the input 1/s2 i. e. Laplace transform of a unit-ramp input. For example, consider the system: Y(s) 1 =2 R (s) s + s + 1 With a unit-ramp input, R(s) = 1/s2, the output can be written in the form: Y(s) = 1 1 1 R (s) = 2 ? s + s +1 (s + s + 1)s s 2 1 ? ?1 =? 3 2 ?s + s + s ? s which is equivalent to multiplying by 1/s and then working out the step response. To plot the unitramp response of this system, we enter the numerator and denominator coefficients of the term in square brackets into MATLAB: num = [0 0 0 1]; en = [1 1 1 0]; and use the step command: step(num,den) The unit ramp response will be plotted by MATLAB as shown below. Step Response 12 10 Amplitude 8 6 4 2 0 0 2 4 6 Time (sec. ) 17 8 10 12 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. 4. Arbitrary response To obtain the time response of the LTI sys tem SYS=tf(num,den) to an arbitrary input (e. g. exponential function, sinusoidal function .. etc. ), we can use the lsim command (stands for ‘linear simulation’) as follows: lsim(SYS,r,t) or lsim(num,den,r,t) here num and den are the row vectors of the numerator and denominator coefficients of the transfer function, r is the input time function, and t is the time range over which r is defined. Example: Use MATLAB to obtain the output time response of the transfer function: Y(s) 2 = R (s) s + 3 when the input r is given by r = e-t. Solution: Start by entering the row vectors of the numerator and denominator coefficients in MATLAB: num = [0 2]; den = [1 3]; Then specify the required time range and define the input function, r, over this time: t = 0:0. 1:6; r = exp(-t); % Time range from 0 to 6 sec in steps of 0. 1 sec Input time function Enter the above information into the lsim function by typing: lsim(num,den,r,t) This would produce the following plot on the screen. Li near Simulation Results 0. 4 0. 35 Amplitude 0. 3 0. 25 0. 2 0. 15 0. 1 0. 05 0 0 1 2 3 Time (sec. ) 18 4 5 6 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ TUTORIAL PROBLEM SHEET 3 1. Find the transfer function between the input force u(t) and the output displacement y(t) for the system shown below. y(t) b1 u(t) m b2 where b1 and b2 are the frictional coefficients. For b1 = 0. 5 N-s/m, b2 = 1. 5 N-s/m, m = 10 kg and u(t) is a unit-impulse function, what is the response y(t)? Check and plot the response with MATLAB. 2. For the following circuit, find the transfer function between the output voltage across the inductor y(t), and the input voltage u(t). R u(t) L y(t) For R = 1 ? , L = 0. 1 H, and u(t) is a unit-step function, what is the response y(t)? Check and plot the result using MATLAB. 3. Find the transfer function of the electrical circuit shown below. R L u(t) y(t) C For R = 1 ? , L = 0. 5 H, C = 0. 5 F, and a unit step input u(t) with zero initial conditions, compute y(t). Sketch the time function y(t) and plot it with MATLAB. 19 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 4. In the mechanical system shown in the figure below, m is the mass, k is the spring constant, b is the friction constant, u(t) is the external applied force and y(t) is the corresponding displacement. Find the transfer function of this system. k u(t) m For m = 1 kg, k = 1 kg/s2, b = 0. 5 kg/s, and a step input u(t) = 2 N, compute the response y(t) and plot it with MATLAB. b y(t) 5. Write down the transfer function Y(s)/R(s) of the following block diagram. R(s) Y(s) K +_ G(s) a) For G(s) = 1/(s + 10) and K = 10, determine the closed loop transfer function with MATLAB. b) For K = 1, 5, 10, and 100, plot y(t) on the same window for a unit-step input r(t) with MATLAB, respectively. Comment on the results. c) Repeat (b) with a unit-impulse input r(t). 6. Find the closed loop transfer function for the following diagram. R(s) E(s) Y(s) G(s) +_ F(s) H(s) a) For G(s) = 8/(s2 + 7s + 10) and H(s) = s+2, determine the closed loop transfer function with MATLAB. ) Plot y(t) for a unit-step input r(t) with MATLAB. 7. Determine the transfer function of the following diagram. Check your answer with MATLAB. _ R(s) +_ s s + + 1/s s 20 1/s Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 8. Determine the transfer function of the following diagram. R(s) +_ +_ 50 s +1 Y(s) s 2/s 1/s2 2 +_ a) Check you result with MATLAB. b) Plot y(t) for a unit-impulse input r(t) with MATLAB. 9. Determine the total output Y(s) for the following system. D(s) How to cite Transfer Functions, Essay examples

Operating System Memory Management

Question: Discuss about theOperating Systemfor Memory Management. Answer: Introduction An operating system is defined as a software program that helps in enabling the hardware of the computer in order to communicate with the software system. Today, every computer system have Graphical user interface as an operating system that makes the system easier for various operation (Agne et al. 2014). They help in allowing a user to enter the commands by pointing at the objects that appears on the screen. The essay helps in unearthing various concepts of operating system and its history. The assignment also describes the functions of various managers and Basic Techniques of Memory Management and the evolution of memory allocation schemes. Discussion Operating System An operating system is defined as a program which when unloaded in a computer with the help of the boot program, helps in managing all other programs, which are present in the computer system (Belay et al. 2014). The other programs, which are managed by the operating system, are known as application program. The application program uses the operating system by requesting for services with the help of specific application program. The users can interact properly by using a user interface, which includes graphical user interface and command line (Brittain et al. 2014). There are various types of operating system, which includes single and multi-tasking, single and multi- user, distributed operating system and many more. Figure1: Common Features of Operating System (Source: Czakon and Mitov 2014) An operating system performs a number of services for various applications. In a multitasking operating system, a number of programs are running at the same time, it is the task of the operating system to determine the time required for each program before providing a turn to another program (Dawson-Haggerty et al. 2013). The operating system also helps in providing messages to various interactive users about the status or error that may have occurred. All computers platforms whether hardware or software require an operating system therefore an operating system must be built or developed with some specific features in order to meet various requirements of the users. History of Operating System In earlier days, computers are mainly used as calculators in order to perform a single task. The feature of basic operating system was mainly designed after the 1950s (Dixon et al. 2012).The functions of basic operating system includes resident monitor that helps n running various programs in succession automatically in order to speed up the operating system. Operating system was not present in modern as well as complex form until 1960s (Kivity et al. 2014).Many hardware features were added that helps in enabling interrupts, runtime libraries and many more. In 1980s when computer became popular in the market, then operating system was developed with the same concept that was used earlier. In 11940s, the electronic system does not have operating system. Electronic systems at that time were programmed on rows of mechanical switches or with the help of jumper wires. After the invention of general-purpose computers, machine language was introduced in the system (Lin and Zhong 2014). In 1950s a computer was introduced which is helpful in executing a single program at a time. Later on machines were developed with different libraries of programs, which are linked to a user program for assisting various operations including generation of computer codes. Main Task of Managers Memory Manager The main task of the memory manager is to control and co-ordinate the memory of the computer by assigning different sections to various programs that are helpful in optimizing the overall performance of the system (Monaco et al. 2013). In the hardware section, the memory management consists of various components, which includes storing of physical data such as RAM, chips and many more. In the application level, the memory manager helps in ensuring the availability of proper as well as adequate memory for the structures of the data in order to run programs at all time (Nikolaev and Back 2013). The memory manager helps in combining the two tasks, which are related with the recycling and allocation procedure. Process Manager The process manager plays an integral role in operating system. They allocate resources for processing, enabling and exchanging information in order to protect the resources for enabling various types of synchronization among processes (Paczkowski et al. 2015). In order to meet all these requirements and needs, the operating system maintains a specific data structure for a particular process, which helps in describing both the state and resource ownership and they are related with the processes that enables the operating system in order to control the overall process (Rainie and Wellman 2012). The main functions of the process manager includes allocation of resources to various processes, enabling processes in order to share various information, protecting various resources and enabling synchronization for different processes. File Manager The computer systems generally employ secondary storage devices for providing non-volatile storage system for storing various types of programs and data (Walter and Karlsson 2014). The file manager works with the programs and the user data, which are held together in the form of discrete storage systems. They are responsible for keeping space for various files on secondary medium (Agne et al. 2014). The main functions of the file manager include navigation, operations, storage, communication and security. The file manager includes the access and data integrity process under the aspect of security. File managers generally handles the programs or tasks that are related the management procedure of file storage system. They perform functions, which is helpful in automatically alerting the users for carrying out several functions manually. Device Manager Hardware devices help in providing the ability to input as well as output the data from the computer. In order to support various hardware devices, various types of application programming were used (Belay et al. 2014). The applications programming that are used by the device manager. The different application program utilizes System Call API in order to request preset input output request from the operating system. The device manager uses various types of algorithms in order to process the request, which is independent of the device (Brittain et al. 2014). The device managers uses device driver, which is considered as third party software that helps in interacting various devices. Basic Techniques of Memory Management and the Evolution of Memory Allocation Schemes There are four main techniques of Memory Management. The techniques are single contiguous allocation, partitioned allocation, paged memory management and segmented memory management. Single allocation is considered as the most simple memory management technique (Czakon and Mitov 2014). The system that uses single allocation technique uses multitasking procedure by swapping the contents that are present inside the memory for switching among various users. Partitioned technique of allocation helps in dividing the primary memory into several partitions, which mainly consists of the contiguous sections of memory (Dawson-Haggerty et al. 2013). It mainly requires some hardware support in order to prevent the jobs from interfering with different operating systems. Paged allocation helps in dividing the memory of the computer in fixed size units, which is known as page frames (Dixon et al. 2012). The memory management system of the hardware uses physical allocation of memory on a specific page while the addressing space appears to be contagious. Segmented memory is one of the techniques that helps in providing linear as well s contagious memory space (Kivity et al. 2014). They mainly need hardware support in the form of segment table that mainly contains the physical address in the form of size, memory and many more. It helps in allowing better protection for access than any other schemes. There are number of memory allocation schemes, which include single partition allocation, multi-partition allocation, fixed variable size partition, dynamic partitioning and placement algorithm (Lin et al. 2014). Memory allocation can fixed in size or it can change in size for increasing and decreasing the size of the data for accommodating various requirements of change. The memory allocation technique is mainly defined as the process that helps n assigning the block of memory after request (Nikolaev and Back 2013).The allocator receives memory from various operating systems in order to satisfy the request from the smaller blocks. The main memories usually have two partitions, which include low memory and high memory, and the procedure of allocation is divided into single partition allocation and multiple partition allocation. In single partition allocation, relocation register scheme is used for protecting the user processes from each other and in multiple partition allocation; the main memory is divided into number of fixed-sized partitions. Conclusion It can be concluded that operating system is very much necessary in modern computer system. It helps in managing the other programs are generally application programs. The application program utilizes the operating system by demanding for services with the help of detailed application program. The users can cooperate appropriately by using a user interface, which includes graphical user interface and command line. The assignment analyzes that there are number of tasks, which allocated to different managers of the system for its smooth operation. The different techniques of memory management that are described in the assignment are very much useful for the operating system. 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