Author: jorgemayorga

FPGA INTRODUCTION

Posted on by jorgemayorga

FPGA and Digital Design for Advanced Applications: Digital Control Systems, Sensor Fusion, Simulation Systems, and Machine Learning

1.1 The Evolution of Digital Design and FPGA

Digital design is at the heart of modern electronics, driving innovations from the tiniest embedded systems to the most powerful supercomputers. Fundamentally, digital design involves creating circuits that process discrete signals, typically represented as binary numbers. Over the decades, digital design has evolved significantly, propelled by advancements in semiconductor technology, design methodologies, and increasing computational demands.

The history of digital design dates back to the early 20th century, with the advent of the first electronic computers. Early digital circuits were built using vacuum tubes, which were large, unreliable, and power-hungry. These limitations spurred the development of more efficient technologies. The invention of the transistor in 1947 by John Bardeen, Walter Brattain, and William Shockley at Bell Labs marked a significant turning point. Transistors were smaller, more reliable, and consumed less power, paving the way for the miniaturization of electronic circuits.

The 1960s and 1970s witnessed the rise of integrated circuits (ICs), where multiple transistors were fabricated on a single silicon chip. This era marked the beginning of Moore’s Law, the observation made by Gordon Moore, co-founder of Intel, that the number of transistors on a chip would double approximately every two years, leading to exponential growth in processing power. The development of ICs led to the creation of more complex digital circuits, including microprocessors, which could perform a variety of tasks by executing programmed instructions.

As digital design advanced, so did the methodologies used to create these circuits. The introduction of Hardware Description Languages (HDLs) such as VHDL and Verilog in the 1980s revolutionized digital design by allowing engineers to describe the behavior and structure of digital systems at a high level of abstraction. This shift enabled more complex designs and facilitated simulation and verification processes, significantly reducing design time and errors.

The evolution of digital design also saw the emergence of Field-Programmable Gate Arrays (FPGAs) in the mid-1980s. FPGAs, introduced by companies like Xilinx and Altera, provided a flexible alternative to fixed-function ICs. They allowed designers to reprogram hardware post-manufacture, enabling rapid prototyping, iterative design, and adaptation to changing requirements. This flexibility has made FPGAs indispensable in various applications, from consumer electronics to aerospace.

Today’s digital design encompasses a wide array of disciplines, including combinational and sequential logic, state machines, digital signal processing (DSP), and more. Modern digital circuits range from small arithmetic units to large, complex systems such as machine learning accelerators and high-performance computing units. The sophistication of digital design techniques continues to grow, driven by the need for higher performance, lower power consumption, and greater integration.

In recent years, the integration of artificial intelligence and machine learning into digital circuits has become a major trend. FPGAs and other programmable logic devices are increasingly used to accelerate machine learning algorithms, providing the parallel processing capabilities required for tasks such as image recognition, natural language processing, and predictive analytics. This integration is transforming industries and pushing the boundaries of what digital design can achieve.

As we look to the future, digital design will continue to evolve, driven by emerging technologies such as quantum computing, neuromorphic engineering, and advanced semiconductor materials. These innovations promise to further expand the capabilities of digital systems, enabling new applications and driving the next wave of technological advancements.

1.2 The Role of FPGAs in Modern Electronics

Field-Programmable Gate Arrays (FPGAs) are a pivotal technology in the realm of digital design. Unlike traditional fixed-function integrated circuits (ICs), FPGAs offer unparalleled flexibility by allowing designers to reconfigure their hardware to suit specific applications. This reconfigurability is achieved through a matrix of programmable logic blocks interconnected by programmable routing resources.

FPGAs bridge the gap between the performance of custom ASICs (Application-Specific Integrated Circuits) and the flexibility of software running on general-purpose processors. They are particularly valuable in applications where high performance, low latency, and parallel processing are crucial. From telecommunications and aerospace to automotive and consumer electronics, FPGAs have become integral to a wide array of industries.

1.3 Why Choose FPGAs?

Several key attributes make FPGAs an attractive choice for modern digital design:

  1. Reconfigurability: FPGAs can be reprogrammed multiple times, allowing for iterative development and rapid prototyping. This flexibility is particularly useful in research and development environments where requirements may change frequently.
  2. Parallel Processing: FPGAs excel at tasks that can be parallelized. Unlike traditional processors that execute instructions sequentially, FPGAs can perform many operations simultaneously, significantly boosting performance for suitable applications.
  3. Customizability: Designers can tailor FPGA configurations to meet specific application requirements, optimizing for performance, power consumption, and area. This level of customization is not possible with off-the-shelf processors.
  4. Latency: FPGAs offer deterministic execution with minimal latency, making them ideal for real-time applications such as digital control systems and high-frequency trading.
  5. Integration: Modern FPGAs often include embedded processors, high-speed transceivers, and other specialized blocks, providing a comprehensive solution on a single chip.

1.4 Overview of FPGA Applications

FPGAs are versatile and find applications in a broad spectrum of fields. This book focuses on four primary areas where FPGAs have made a significant impact:

  1. Digital Control Systems: FPGAs are used to implement high-speed, deterministic control systems for applications such as motor control, power management, and industrial automation. Their ability to process inputs and produce outputs with minimal delay is crucial for maintaining stability and performance in these systems.
  2. Sensor Fusion: In applications such as autonomous vehicles and robotics, FPGAs are employed to integrate and process data from multiple sensors in real time. This capability enables more accurate and reliable decision-making.
  3. Simulation Systems: FPGAs play a critical role in simulation and emulation systems, providing the computational power needed to model complex physical systems in real time. They are used in areas such as hardware-in-the-loop (HIL) testing and real-time simulation.
  4. Machine Learning: The parallel processing capabilities of FPGAs make them well-suited for implementing machine learning algorithms, particularly for inference tasks. FPGAs can accelerate the execution of neural networks and other machine learning models, offering a balance between performance and power efficiency.

Part 1: Introduction to FPGAs and Digital Design

  1. Introduction to Digital Design
    • Basics of digital logic
    • Combinational vs. sequential logic
    • Design methodologies
  2. Introduction to FPGAs
    • What is an FPGA?
    • FPGA architecture
    • Differences between FPGAs, ASICs, and microcontrollers
    • Overview of FPGA development tools (e.g., Xilinx Vivado, Altera Quartus)
  3. Hardware Description Languages (HDLs)
    • VHDL basics
    • Verilog basics
    • Comparison of VHDL and Verilog
    • Simulation and synthesis

Part 2: FPGA Design Process

  1. Design Entry
    • Schematic entry
    • HDL coding guidelines
    • Behavioral and structural modeling
  2. Simulation and Verification
    • Functional simulation
    • Timing simulation
    • Testbenches and test vectors
    • Debugging techniques
  3. Synthesis and Implementation
    • Synthesis process
    • Constraints and optimization
    • Place and route
    • Timing analysis
  4. Configuration and Debugging
    • FPGA configuration methods
    • On-chip debugging tools (e.g., logic analyzers, Integrated Logic Analyzers)
    • In-system programming

Part 3: Digital Control Systems

  1. Fundamentals of Digital Control
    • Control system basics
    • Discrete-time control theory
    • Difference equations and z-transform
  2. FPGA Implementation of Controllers
    • PID controllers
    • State-space controllers
    • Digital filters
  3. Case Studies
    • Motor control
    • Power electronics control

Part 4: Sensor Fusion

  1. Introduction to Sensor Fusion
    • Types of sensors and their characteristics
    • Basics of sensor fusion
  2. Algorithms for Sensor Fusion
    • Kalman filter
    • Extended Kalman filter
    • Complementary filter
    • Particle filter
  3. FPGA Implementation of Sensor Fusion Algorithms
    • Parallel processing in FPGAs
    • Case study: Inertial Measurement Unit (IMU) sensor fusion

Part 5: Simulation Systems

  1. Introduction to Simulation Systems
    • Types of simulations (e.g., real-time, discrete-event)
    • Importance of simulations in design and testing
  2. Design and Implementation of Simulation Systems on FPGAs
    • High-level synthesis (HLS)
    • Co-simulation with software
  3. Case Studies
    • Real-time simulation of physical systems
    • Hardware-in-the-loop (HIL) simulation

Part 6: Machine Learning

  1. Introduction to Machine Learning on FPGAs
    • Why use FPGAs for machine learning?
    • Overview of machine learning algorithms
  2. Implementing Machine Learning Algorithms on FPGAs
    • Linear regression
    • Decision trees
    • Neural networks (including deep learning)
  3. Optimization Techniques
    • Quantization and fixed-point arithmetic
    • Parallel and pipelined implementations
  4. Case Studies
    • Image recognition
    • Anomaly detection
    • Real-time inference

Part 7: Advanced Topics and Future Trends

  1. Emerging FPGA Technologies
    • Advances in FPGA architectures
    • Low-power design techniques
  2. Future Trends in Digital Design and FPGA Applications
    • Integration of AI and ML in FPGAs
    • Advances in sensor fusion algorithms
    • Trends in digital control systems

FPGA Kalman Filter

Posted on by jorgemayorga

https://github.com/jlmayorgaco/fpga-kalman-filter

Kalman filters represent a cornerstone in signal processing and control theory, offering an elegant solution for state estimation in dynamic systems. These filters excel in their ability to fuse noisy sensor measurements with a dynamic model of the system, providing optimal estimates of the true state. With applications spanning diverse fields such as aerospace, robotics, and finance, Kalman filters play a vital role in enabling accurate and reliable estimation, prediction, and control tasks. While their mathematical elegance and efficiency are commendable, Kalman filters do have limitations, particularly in nonlinear and non-Gaussian scenarios where extended and unscented variants are needed

FPGAs (Field-Programmable Gate Arrays) are versatile hardware platforms that offer immense flexibility and parallel processing capabilities. Their reconfigurability allows for rapid prototyping and customization of digital circuits, making them ideal for implementing complex algorithms like Kalman filters. With FPGA-based implementations, developers can achieve real-time performance, low latency, and resource-efficient designs. However, FPGA development often requires specialized expertise and incurs higher development costs compared to software-based solutions.

Combining Kalman filters with FPGA technology unlocks a realm of possibilities for real-time signal processing applications. FPGA-based Kalman filters offer the potential for high-performance, low-latency implementations suitable for demanding scenarios such as drone navigation and power grid management. By leveraging FPGA’s parallel processing capabilities, Kalman filters can efficiently handle large volumes of sensor data, enabling accurate state estimation and control in dynamic environments. However, FPGA-based solutions may face challenges related to power consumption, complexity, and scalability, requiring careful consideration in design and implementation.

In comparing Kalman filter implementations on FPGA platforms, two key applications stand out: drone navigation and power electronics in microgrid renewable energy systems. In drone navigation, FPGA-based Kalman filters can enhance onboard sensor fusion and localization, enabling precise flight control and autonomous navigation. Similarly, in microgrid systems, FPGA-based Kalman filters can optimize energy management and grid stability by accurately estimating renewable energy sources’ output and predicting load demand. By comparing different Kalman filter architectures and FPGA implementations in these applications, we aim to uncover insights into their performance, efficiency, and suitability for real-world deployment.

What is the Kalman Filter?

At its core, the Kalman filter is an algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone. It achieves this by predicting the state of the system at the current time step and then correcting this prediction using the measurement data.

Key Concepts and Theory:

  1. State Space Model:
    • The system is represented as a set of linear equations where the state of the system evolves over time according to a linear dynamic model. The state variables represent quantities of interest that are to be estimated.
  2. Prediction Step:
    • In the prediction step, the Kalman filter uses the state transition model (which describes how the state evolves from one time step to the next) and the control inputs (if available) to predict the state of the system at the current time step.
  3. Update Step:
    • In the update step, the filter combines the predicted state with the new measurement information, using the Kalman gain, to obtain an optimal estimate of the current state.
  4. Kalman Gain:
    • The Kalman gain determines how much weight is given to the predicted state versus the new measurement. It is computed based on the covariance of the predicted state and the measurement noise.
  5. Covariance Matrix:
    • The Kalman filter maintains a covariance matrix that represents the uncertainty of the state estimate. This matrix is updated at each time step based on the predictions and measurements.

How Does It Work?

Let’s break down the Kalman filter process step by step:

  • Initialization: Begin with initial estimates of the state variables and their covariance matrix.
  • Prediction:
    • State Prediction: Predict the state of the system at the current time using the state transition model.
    • Covariance Prediction: Predict how uncertain the state estimate is using the covariance matrix and the process noise (uncertainty in the state transition).
  • Update:
    • Kalman Gain Calculation: Calculate the Kalman gain based on the predicted covariance, the measurement noise covariance, and the observation matrix (relating measurements to the state variables).
    • State Update: Update the state estimate using the predicted state, the Kalman gain, and the difference between the predicted measurement and the actual measurement.
    • Covariance Update: Update the covariance matrix to reflect the reduced uncertainty after incorporating the new measurement.

Applications:

The Kalman filter finds applications in a wide range of fields:

  • Navigation Systems: Estimating the position and velocity of vehicles using noisy GPS measurements.
  • Robotics: Tracking the position of a robot using noisy sensor data.
  • Finance: Estimating stock prices or other financial variables using noisy market data.
  • Control Systems: Estimating the state of a controlled system to optimize control actions.

Literature Review 2013 – 2023 Kalman Filter in Power Systems


* The average document age of 5.37 years suggests that the field is relatively young but maturing. An average of 12.74 citations per document indicates a moderate level of impact and recognition within the academic community.

* The high number of Keywords Plus ( Keywords Plus (ID): 5064, Author’s Keywords (DE): 2035) and Author’s Keywords indicates a wide variety of research topics and themes within the field. This diversity suggests that the field is multidisciplinary and covers numerous subtopics.

* With only 14 authors of single-authored documents, it is evident that collaboration is common in this research area. The majority of the research is conducted by teams rather than individual authors ( Grouped in 5 major clusters)

* An average of 3.56 co-authors per document highlights a collaborative research environment. The international co-authorship rate of 21.86% shows significant global collaboration, indicating that the research area is internationally recognized and researchers frequently work across borders.

* The majority of the documents are journal articles (360) and conference papers (281), which is typical for many scientific fields. The presence of 51 review papers suggests that there are substantial efforts to synthesize and summarize existing research, which is crucial for guiding future studies. (around 12%)

IELTS: List of Writing Tasks

Posted on by jorgemayorga

IELTS Essay Topics on Culture and Tradition

  1. Some claim that when cultural practices are utilized as tourist attractions intended to generate revenue, they are destroyed. Some claim that this is the only way to keep certain customs alive.
  2. Just like the government spends funds on music and theatre, it does the same on arts too which is considered a waste of money. Don’t you think that the government should spend more on revamping public services? Do you agree? If not, then why?
  3. Many monuments, which are a part of our cultural diversity are protected and reconstructed by law. A few people think these structures should be destroyed and something new should be constructed. How important is it to put more effort into monument maintenance? Do you think that through their maintenance, history is coming in the way of progress?
  4. A single-world culture is being created due to modern technology. Do you agree or disagree?

IELTS Essay Topics on Environment

  1. Some people believe raising the price of fuel is the greatest way to address global environmental issues. Do you agree or disagree?
  2. Many animal species are becoming endangered as a result of habitat loss brought on by urbanisation, illicit hunting, and deforestation; some are even at risk of going extinct. Do you think it is necessary to protect animals?
  3. According to you, what are the major problems due to which developed countries have become the major contributors to global warming? What are the main problems leading to global warming?
  4. One of the most critical issues that the environment is facing is global warming. What are the measures the government can take to reduce such issues?
  5. Overpopulation in the country is a serious issue that has given rise to numerous problems. Elaborate on one or two serious issues and give a plausible solution for them that governments can implement.
  6. Some people think that the government should strictly control the supply of fresh water, as it is a limited resource, while others it should not be regulated.
  7. Fossil fuels are the main source of energy around the world today. In some countries, the use of alternative sources of energy is replacing fossil fuels.

Topics on Media 

12. Media violence encourages violence in society. To what extent do you agree?

13. Most of the news that is reported is terrible news, such as stories about wars, famines, accidents, and crime. How come, in your opinion? Do you believe there should be both good and negative news?

14. Do you believe that celebrities are ill-treated by the media or it is the price they have to pay for their stardom? Regardless of fame, their privacy should be respected or not?

15. Media has unintentionally left a negative impact on children. Often, they end up watching violence which is not advised at such a tender age. Do you agree or disagree with this?

16. What are your views on the false means of advertising used by media agencies?

17. What is the impact of computer games on the children of today? Is it helping their development or making them worse? Why and why not? Use specific reasons and examples to support your answer.

18. Successful sportsmen can earn a great deal more than people in other important professions. Some people think this is fully justified while others think it is unfair. Discuss both views and give your own opinion.

19. Some people believe that advertising has a strong effect on a person’s decision-making process. Others feel that it has little or no real impact. Discuss both views and give your own opinion.

20. Does advertising encourage us to buy things we don’t need or does it tell us about new products that may improve our lives. Which view do you agree with?

21. In many countries today, crime novels and TV crime dramas are becoming more and more popular.

22. Much worry is being expressed about the educational divide between affluent and poorer nations. What options do you have for handling this situation.

23. The role of education is to educate children for the modern world. Schools should remove music and the arts from the curriculum so that students can concentrate on practical courses like computer technology. How much do you agree?

24. Education is a fundamental right. Thus, it should be free of cost for everyone regardless of personal wealth. Do you agree or disagree with it?

25. While few people believe that the education provided by universities helps graduates get better jobs. Others think that there are many wider advantages of education through universities. Elucidate upon these views and give your opinion. 

26. Do you align with the thought that educational activities must be incorporated into children’s free time? What do you think about this argument?

27. Co-ed schools are considered better than boys and girls being educated separately. Discuss both sides and give your own opinion.

28. Some people believe that the traditional approach in the modern classroom is better than a teaching methodology based on experiential learning. Do you agree or disagree?

29. University students should pay the full cost for their own study because a university education benefits individuals rather than society. To what extent do you agree or disagree?

30. Is teaching people over 65 to use computers the best way to spend government money? To what extent do you agree?

31. Nowadays, not enough students choose science subjects at university in many countries. Why is this? What effects does this have on society?

32. Some feel that movies and TV shows are a good way to study history despite their lack of historical accuracy at times. To what extent do you agree or disagree?

33. The most important aim of science ought to be to improve people’s lives.

34. Government money should be used to support children in school for sports rather than to support professional sports and arts that perform for the general public.

Topics on Society

35. Homeless individuals are a part of most societies. Some individuals believe that giving them money is the greatest way to assist them. What percentage would you agree with?

36. It is observed in many countries that women do not feel the need to get married. Locals believe that women have started earning and have become independent as they have their own source of income, thus, they do not require the financial security that marriage brings. Up to what extent do you agree or disagree with this statement?

36. It is always believed that globalization has both advantages as well as disadvantages. State prominent advantages as well as disadvantages in your opinion.

37. Traditional ways of living are being lost as modern civilization develops. Is it crucial to maintain our old ways of living?

38. Over the last decade, it was majorly seen that people were eager to move from rural areas toward urban areas. What do you think has caused this? What problems can this bring up?

39. Every culture around us has made its mark in history in one or the other way. Why do you think it is important to familiarise the next generation with history?

40. Some people spend more and some spend less for wedding parties, birthday parties, and other celebrations. Is it a waste of money or a social requirement? Include specific details and examples to support your choice.

41. Some people believe that in the near future, there will be no borders between countries, while others feel that national borders will always remain. Discuss both views and give your own opinion.

42. The teenage years are the happiest times of most people’s lives. Others think that adult life brings more happiness in spite of greater responsibilities. Discuss both views and give your own opinion.

43. People who have original ideas provide much greater value to society than the ones who copy others. Do you agree or disagree?

44. Is it good for childrens that parents provide them with everything they ask for?

45. Advancements in technology have made it possible for many people to work from home nowadays? What do you think are the effects on employees working from home?

46. Some people think that social networking sites have a huge negative impact on both individuals and society. To what extent do you agree or disagree?

47. The best way to reduce poverty in developing countries is by giving up to six years of free education so that they can at least read, write and use numbers. To what extent do you agree or disagree?

48. Some argue that patriotism is the primary cause of wars globally. Others feel that it serves to prevent less ethical politicians from running a country and starting wars.

49. Many think that religion should be taught in schools while others think it should be avoided

50. Some feel that cities should be designed to be beautiful while others feel their functionality is more important. Discuss both sides and give your own opinion

51. Preservatives and chemicals are present in many prepared meals and processed foods. What benefits can this have? Do you believe the benefits outweigh the drawbacks?

52. Many children around us are obese and overweight. What according to you has led to this common problem amongst children? What measures can be taken to resolve this? 

53. To cope with the pace of the fast-moving world, many of us have now started to replace main meals with fast food. What according to you are the advantages of this step that have to outweigh the disadvantages? 

54. Over the past few years, the media has portrayed the image of a young woman as a thin lady. What according to you are the problems caused by this conception? 

55. Due to the severe repercussions of eating fast food on a daily basis, some people think that the only way to prevent this is to ban fast food. Do you agree or disagree with the statement?

56. In many countries, fast food is becoming cheaper and more widely available. Do the disadvantages of this outweigh the advantages?

57. People often argue that eating junk food has led to an unhealthy lifestyle. This problem has become more common among young people these days. Do you agree or disagree that junk food is the cause of the issue? 

58. Governments in many countries have recently introduced special taxes on foods and beverages with high levels of sugar. Some think these taxes are a good idea while others disagree. Discuss both views and give your opinion.

59. Today’s society provides people with various ways to lose weight, such as special diets or exercise regimes. Many people believe though that poor food and today’s lifestyle should be addressed first. What is your opinion?

60. In many countries today, the eating habits and lifestyles of children are different from those of previous generations. Some people say this has had a negative effect on their health in many countries today, the eating habits and lifestyles of children are different from those of previous generations. Some people say this has had a negative effect on their health. What is your opinion?

61. Nowadays, an increasing number of people with health problems are using alternative medicines and treatments instead of visiting their normal doctor.

Topics on Communication and Personality 

62. Individuals and businesses alike are choosing to communicate professionally or socially via technology rather than in person. Talk about the benefits and drawbacks of using technology for communication.

63. Some people fail in school but end up being successful in life. What do you think is important in life- performing well in school or being successful after school? 

64. With the advent of the internet, texting has become the modern way of communicating due to which face-to-face communication will become a thing of the past. To what extent do you agree? 

65. With the help of the internet, many people have now started to communicate with others online comfortably rather than confronting them face to face. According to you, what are the advantages as well as disadvantages of communicating online? 

66. Due to frequent slang or short forms used in the modern way of texting, people have started believing that this is the death of grammar and spelling. Discuss both sides of the argument.

67. New-age Celebrities from Instagram and TikTok are more famous for their glamorous lifestyle than their achievements. Does this affect the children who follow them? State your opinion.

68. Some people prefer to keep their private life separate from their work while others spend their leisure time with their colleagues. Discuss both views and give your opinion

69. Has modern technology made it easier to download copyrighted music and books?

70. Some children spend hours every day on smartphones. Why is this the case? Do you think this is a positive or negative development?

71. It is important for people to take risks, in both their professional lives and personal lives.

72. The best way to make the road transport of goods safer is to ask drivers to take a driving test each year.

73. Fewer young people play sports these days.

74. Some nations are having trouble keeping up with rising crime rates. Many individuals believe that the best solution to decrease crime is to have more police officers on the streets. How much do you concur?

75. People believe that certain criminals should be made to do community service instead of putting them behind bars. Up to what extent do you agree? 

76. To what extent do you think that technology has played a role in decreasing the crime rate? 

77. In some societies, the crime rate committed by teenagers is increasing. Thus, the people believe that they should receive punishments like adults. According to you what are the disadvantages of it?

78. Do you agree or disagree that having more police on the streets will decrease the overall crime rate of a country?

79. Studies show that most young children who commit crimes have been abused in some way by their parents.

80. Many studies show that poor people are more likely to be involved in petty and serious crimes than people who come from higher-income groups. Do you agree?

81. What is the importance of stable family structures in preventing crime in a country? State your opinion.

82. Are strict punishments for driving offences the key to reducing traffic accidents or are other ways necessary? Give your opinion.

83. Prison is the common way most countries try to solve the problem of crime. However, a more effective solution is to provide the public with a better education.

Other Questions

Apart from these category-wise questions, here are some other general IELTS essay topics:

84. Some people believe that one of the most beneficial inventions like mobile phones has somehow disrupted our social lives. What is your view on this statement?

85. Being a young mind, do you agree that people should take advice from elders rather than from the younger ones? Support your answer with valuable points 

86. The increasing dependency of people on their mobile phones is a positive or negative development in society? 

87. Some people think that wearing a uniform at work is essential whereas others think that it is unnecessary. Present your views on both sides of the argument.

88. Have you ever lived away from your parents? Describe your living situation and explain its advantages and disadvantages. Include specific details and examples to support your choice.

90. Some people prefer to work in the same type of job throughout their lifetime while others like to change the type of job they do. Discuss both views and give your opinion.

91. Some people think that illegal Internet downloads are having a negative effect on the music industry. Others feel that they have little or no impact on artists. Discuss both views and give your own opinion.

92. People who read for pleasure in their free time have a better imagination than those who prefer to watch TV. To what extent do you agree or disagree?

93. Children often complain that history lessons are boring because they are about a past that is dead. How can schools bring history alive for pupils?

94. People are waiting until their thirties to get married and have children these days. Do you think this is a positive or negative development?

95. Some people say a car is the best way to travel through a city while others support travelling with bicycles. Discuss both sides and share your opinion.

96. Would you prefer working for a large company or a small one? Explain with specific reasons and examples.

97. Free public transport 24×7 is the best way for governments to solve the problem of traffic congestion. Do you agree or disagree?

98. Music has been and will continue to be the universal language of mankind. To what extent do you agree or disagree?

99. Online currencies have become more common in recent years. Why is this? Is this a positive or negative development?

100. Some people feel that cities should allow for spaces for graffiti while others feel it should be banned. Discuss both sides and give your own opinion.

101. Always telling the truth is the most important consideration in any relationship between people. To what extent do you agree or disagree?

102. A rise in the standard of living in a country often only seems to benefit cities rather than rural areas.

103. Around the world, rural people are moving to cities and urban areas, so populations in the countryside are decreasing.