Modeling and practical design issues for average current control
System Modeling and Simulation
System Modeling and SimulationSystem modeling and simulation is a critical process that helps organizations to design, develop, and test complex systems before they are implemented. It involves creating a virtual model of the system and simulating its behavior under different conditions to identify potential issues and optimize its performance. The use of system modeling and simulation has become increasingly important in various industries, including aerospace, automotive, defense, healthcare, and manufacturing. In this response, I will discuss the importance of system modeling and simulation, its benefits, challenges, and future trends.First and foremost, system modeling and simulation help organizations to reduce the risk of failure and save costs. By creating a virtual model of the system, engineers can identify potential issues and optimize its performance before it is implemented. This helps to reduce the risk of failure and minimize the cost of rework. For example, in the aerospace industry, system modeling and simulation are used to test the performance of aircraft before they are built. This helps to identify potential issues and optimize the design, which can save millions of dollars in development costs.Secondly, system modeling and simulation help organizations to improve their decision-making process. By simulating the behavior of the system under different conditions, engineers can evaluate the impact of different design choices and make informed decisions. This helps to reduce the risk of making costly mistakes and ensures that the system meets the requirements of the stakeholders. For example, in the healthcare industry, system modeling and simulation are used to evaluate the impact of different treatment options on patients. This helps doctors to make informed decisions and provide the best possible care to their patients.Thirdly, system modeling and simulation help organizations to improve their productivity and efficiency. By simulating the behavior of the system, engineers can identify potential bottlenecks and optimize the system's performance. This helps to improve productivity and reduce the time and cost of production. For example, in the manufacturing industry, system modeling and simulation are used to optimize the production process and reduce the time and cost of production.However, there are also challenges associated with system modeling and simulation. One of the biggest challenges is the complexity of the systems being modeled. As systems become more complex, it becomes increasingly difficult to create an accurate model and simulate its behavior. This can lead to inaccurate results and increase the risk of failure. Another challenge is the availability of data. In order to create an accurate model, engineers need access to a large amount of data. However, in some cases, data may not be availableor may be difficult to obtain.Looking into the future, there are several trends that are likely to shape the future of system modeling and simulation. One of the trends is the use of artificial intelligence (AI) and machine learning (ML) to improve the accuracy of models. AI and ML can help to identify patterns in data and create more accurate models. Another trend is the use of cloud computing to improve the scalability and accessibility of system modeling and simulation. Cloud computing allows engineers to access powerful computing resources and collaborate with others in real-time.In conclusion, system modeling and simulation are critical processes that help organizations to design, develop, and test complex systems before they are implemented. They help to reduce the risk of failure, improve decision-making, and improve productivity and efficiency. However, there are also challenges associated with system modeling and simulation, such as the complexity of the systems being modeled and the availability of data. Looking into the future, there are several trends that are likely to shape the future of system modeling and simulation, including the use of AI and ML and cloud computing.。
Geometric Modeling
Geometric ModelingGeometric modeling is a crucial aspect of computer graphics and design,playing a significant role in various industries such as architecture, engineering, and animation. It involves creating digital representations of objects and environments using mathematical and computational techniques. Geometric modeling enables designers and engineers to visualize and analyze complex structures, simulate real-world scenarios, and create stunning visual effects. However, the process of geometric modeling comes with its own set of challenges and limitations, which require careful consideration and innovative solutions. One of the primary challenges in geometric modeling is achieving accuracy and precision in the representation of 3D objects. Designers and engineers often need to create models that closely resemble real-world objects or adhere to specific measurements and standards. This requires the use of advanced mathematical algorithms and computational methods to ensure that the digital models are geometrically accurate and free from errors. Achieving this level of precision can be time-consuming and resource-intensive, especially for complex and intricate designs. Another significant challenge in geometric modeling is the complexity of representing organic and free-form shapes. While traditional geometric shapes such as cubes, spheres, and cylinders can be easily defined using mathematical equations, organic shapes like human figures, animals, and natural landscapes pose a greater challenge. Creating realistic and detailed representations of such shapes requires the use of advanced modeling techniques such as NURBS (Non-Uniform Rational B-Splines) and subdivision surfaces, which allow for more flexible and natural-looking forms. However, mastering these techniques and achieving the desired level of realism often requires extensive skill and experience. Furthermore, geometric modeling also faces challenges related to data interoperability and compatibility. In many cases, digital models need to be shared across different softwareplatforms and integrated into larger design or simulation workflows. However, the lack of standardized file formats and data structures can lead to issues with data loss, format conversion errors, and compatibility issues. This can hinder the seamless exchange and utilization of geometric models across different software applications and industry domains, leading to inefficiencies and workflowdisruptions. In addition to technical challenges, geometric modeling also presents creative and artistic dilemmas for designers and artists. While the use of mathematical algorithms and computational methods is essential for creating accurate and precise models, it can also limit the creative freedom and artistic expression of designers. Striking a balance between technical precision andartistic creativity is often a delicate and iterative process, requiring designers to constantly refine and adjust their models to achieve the desired aesthetic and functional outcomes. Moreover, the rapid advancement of technology and the growing demand for high-fidelity visual content pose a challenge for geometric modeling. As the expectations for realism and detail in digital models continue to rise, designers and engineers are under pressure to deliver increasingly complex and sophisticated models within shorter timeframes. This necessitates the development of more efficient and automated modeling tools and techniques that can streamline the modeling process without compromising quality. Despite these challenges, the field of geometric modeling continues to evolve and innovate, driven by the relentless pursuit of realism, efficiency, and creativity. Researchers and practitioners are constantly exploring new algorithms, computational methods, and software tools to overcome the limitations oftraditional modeling approaches. From the development of machine learning algorithms for automated shape generation to the integration of virtual reality and haptic feedback for immersive modeling experiences, the future of geometric modeling holds great promise for addressing current challenges and unlocking new possibilities. In conclusion, geometric modeling is a multifaceted disciplinethat encompasses technical, creative, and practical challenges. From achieving precision and accuracy in 3D representations to addressing issues of data interoperability and artistic expression, the field of geometric modeling requires a holistic and innovative approach. By embracing technological advancements, fostering interdisciplinary collaboration, and nurturing creative talent, the industry can overcome current challenges and pave the way for groundbreaking advancements in computer graphics and design.。
模型设计与制作 英语
模型设计与制作英语Model Design and Fabrication.Introduction.The field of model design and fabrication encompasses a diverse range of activities, from conceptualization to the final creation of a physical replica. It involves the integration of various skills, including creativity, engineering, and artisanal techniques, to bring a design to life. Whether it's a miniature replica of a building, a complex mechanical system, or a simple three-dimensional object, model design and fabrication require meticulous planning and execution.Stages of Model Design and Fabrication.1. Conceptualization and Design: The first step involves the generation of ideas and the creation of a conceptual design. This involves considering the purpose ofthe model, its intended use, and any specific requirementsor constraints. The designer needs to envision the final product and translate their ideas into a detailed design.2. Materials Selection: The choice of materials is crucial in model design. The materials selected depend onthe purpose, scale, and budget of the project. For instance, if the model is for architectural purposes, materials like plastic, wood, or metal may be used. If it's a mechanical model, precision materials like metal or plastic with specific mechanical properties may be required.3. Prototyping: After the initial design and materials selection, the next step is to create a prototype. This isa scaled-down version of the final model, used to test the design's feasibility and identify any potential issues. The prototype is often built using the same materials as thefinal model.4. Fabrication: Fabrication is the process ofconverting the design into a physical object. This involves cutting, shaping, and assembling the materials according tothe design specifications. Modern fabrication techniques like CNC machining, 3D printing, laser cutting, and welding are commonly used.5. Finishing and Detailing: Once the basic structure of the model is complete, the next step is to add finishes and details. This could include painting, applying decals, adding lighting, or creating textures. The goal is to make the model look as realistic and detailed as possible.6. Testing and Evaluation: Finally, the model is tested to ensure it functions as intended. This may involve checking for any mechanical issues, testing the structural integrity, or verifying the accuracy of the design. Once the model passes the tests, it's ready for use.Applications of Model Design and Fabrication.Model design and fabrication have applications in various industries and fields. In architecture, models are used to visualize and communicate design ideas, aid in planning, and predict construction challenges. In theautomotive industry, models are created for testing and refining designs before production. In the aerospace industry, models are essential for simulating flight conditions and testing components.Models are also used in education to demonstrate complex concepts and principles. They are invaluable tools for students to understand and visualize abstract ideas in subjects like physics, chemistry, and biology.Conclusion.Model design and fabrication is a综合性极强的领域，需要设计师具备创造力、技术知识和精湛的工艺技巧。
地下工程结构英文文献综述范文
地下工程结构英文文献综述范文The Underground Engineering Structure: A Comprehensive Literature ReviewThe field of underground engineering has long been a subject of fascination and importance, as humanity has sought to harness the immense potential of the subsurface for a wide range of applications. From the construction of subterranean transportation networks to the development of vast underground spaces for storage and infrastructure, the challenges and complexities inherent in underground engineering have driven significant advancements in both theoretical and practical knowledge.At the core of underground engineering lies the study of underground structures and their behavior under various loading conditions. These structures, which can range from tunnels and caverns to underground storage facilities and foundations, must be designed and constructed with meticulous attention to detail to ensure their safety, stability, and longevity. The literature in this field is vast and diverse, encompassing a wide range of topics, from the geotechnical properties of the surrounding soil and rock to the structural design principles and construction methodologiesemployed.One of the fundamental aspects of underground engineering is the assessment of the geological and geotechnical conditions of the site. This involves the comprehensive study of the subsurface, including the identification of soil and rock types, their physical and mechanical properties, and the presence of any potential hazards, such as groundwater, faults, or unstable formations. This information is crucial in the design and construction of underground structures, as it helps engineers to anticipate and mitigate potential risks and challenges.Another critical area of focus in underground engineering is the structural design of the underground structures themselves. This includes the analysis of the various loading conditions that these structures will be subjected to, such as earth pressures, water pressures, and seismic forces, as well as the selection of appropriate materials and construction methods to ensure their structural integrity. Numerical modeling and simulation techniques, such as finite element analysis, have become increasingly important in this context, allowing engineers to predict the behavior of underground structures under a wide range of scenarios and optimize their design accordingly.In addition to the technical aspects of underground engineering, thefield also encompasses a range of practical considerations related to the construction and maintenance of underground structures. This includes the development of specialized equipment and techniques for excavation, support, and reinforcement, as well as the implementation of effective safety protocols and quality control measures to ensure the successful completion of underground projects.The literature on underground engineering is vast and diverse, reflecting the multifaceted nature of this field. From the fundamental principles of soil and rock mechanics to the latest advancements in construction methodologies and numerical modeling, the body of knowledge in this area continues to evolve and expand, driven by the ever-increasing demand for underground infrastructure and the need to address the unique challenges posed by the subsurface environment.One of the key trends in the literature on underground engineering is the growing emphasis on sustainability and environmental considerations. As the world grapples with the pressing issues of climate change and resource depletion, there is a growing recognition of the need to develop underground infrastructure that is not only structurally sound and cost-effective but also environmentally responsible. This has led to the exploration of new materials, construction techniques, and design approaches thatprioritize energy efficiency, resource conservation, and the minimization of environmental impact.Another area of active research and development in underground engineering is the integration of advanced technologies, such as robotics, automation, and digital modeling, into the design, construction, and maintenance of underground structures. These technologies have the potential to enhance the efficiency, accuracy, and safety of underground projects, while also providing valuable data and insights that can inform future decision-making and innovation.As the world continues to grapple with the challenges of urbanization, resource scarcity, and environmental degradation, the importance of underground engineering will only continue to grow. The literature in this field, with its rich diversity of topics and perspectives, serves as a valuable resource for engineers, researchers, and policymakers, providing the knowledge and insights necessary to develop the underground infrastructure that will shape the future of our built environment.。
机械专业SCI期刊汇总
名称
因子
难度
网址
征稿启事备注ຫໍສະໝຸດ experimental thermal and fluid science
1.234
容易，8期
Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances basic understanding of heat transfer, thermodynamics and fluid mechanics, and their applications. The journal also publishes papers reporting experimental work together with theory, analysis and numerical studies, and papers analyzing original or existing experimental data, together with theory or numerical results. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, contact resistance, and thermophysical property measurements and techniques. Archival review papers, short communications, invited papers, letters to the Editor, discussions of previously published papers, and book reviews are regular features of the journal, in addition to full-length articles.
英文论文常用语
英文论文常用语Beginning1. In this paper, we focus on the need for2. This paper proceeds as follow.3. The structure of the paper is as follows.4. In this paper, we shall first briefly introduce fuzzy sets and related concepts5. To begin with we will provide a briefBackground on the Introduction1. This will be followed by a description of the fuzzy nature of the problem and a detailed presentation of how the required membership functions are defined.2. Details on xx and xx are discussed in later sections.3. In the next section, after a statement of the basic problem, various situations involving possibility knowledge are investigated: first, an entirely possibility model is proposed; then the cases of a fuzzy service time with stochastic arrivals and non fuzzy service rule is studied; lastly, fuzzy service rule are considered.Review1. This review is followed by an introduction.2. A brief summary of some of the relevant concepts in xxx and xxx is presented in Section 2.3. In the next section, a brief review of the .... is given.4. In the next section, a short review of ... is given with special regard to ...5. Section 2 reviews relevant research related to xx.6. Section 1.1 briefly surveys the motivation for a methodology of action, while 1.2 looks at the difficulties posed by the complexity of systems and outlines the need for development of possibility methods.Body1. Section 1 defines the notion of robustness, and argues for its importance.2. Section 1 devoted to the basic aspects of the FLC decision making logic.3. Section 2 gives the background of the problem which includes xxx4. Section 2 discusses some problems with and approaches to, natural language understanding.5. Section 2 explains how flexibility which often ... can be expressed in terms of fuzzy time window6. Section 3 discusses the aspects of fuzzy set theory that are used in the ...7. Section 3 describes the system itself in a general way, including the ….. and also discusses how to evaluate systemperformance.8. Section 3 describes a new measure of xx.9. Section 3 demonstrates the use of fuzzy possibility theory in the analysis of xx.10. Section 3 is a fine description of fuzzy formulation of human decision.11. Section 3, is developed to the modeling and processing of fuzzy decision rules12. The main idea of the FLC is described in Section 3 while Section 4 describes the xx strategies.13. Section 3 and 4 show experimental studies for verifying the proposed model.14. Section 4 discusses a previous fuzzy set based approach to cost variance investigation.15. Section 4 gives a specific example of xxx.16. Section 4 is the experimental study to make a fuzzy model of memory process.17. Section 4 contains a discussion of the implication of the results of Section 2 and 3.18. Section 4 applies this fuzzy measure to the analysis of xx and illustrate its use on experimental data.19. Section 5 presents the primary results of the paper: a fuzzy set model.20. Section 5 contains some conclusions plus some ideas for further work.21. Section 6 illustrates the model with an example.22. Various ways of justification and the reasons for their choice are discussed very briefly in Section 2.23. Section 2 is presented the block diagram expression of a whole model of human DM system24. In Section 2, we shall list a collection of basic assumptions which a ... scheme must satisfy.25. In Section 2 of this paper, we present representation and uniqueness theorems for the fundamental measurement of fuzziness when the domain of discourse is order dense.26. In Section 3, we describe the preliminary results of an empirical study currently in progress to verify the measurement model and to construct membership functions.27. Section 5 is analyzed the inference process through the two kinds of inference experiments...1. In this section, the characteristics and environment under which MRP is designed are described.2. We will provide in this section basic terminologies and notations which are necessary for the understanding of subsequent results. The next section describes the mathematics that goes into the computer implementation of such fuzzy logic statements.3. However, it is cumbersome for this purpose and in practical applications the formulae were rearranged and simplified as discussed in the next section.4. The three components will be described in the next two section, and an example of xx analysis of a computer information system will then illustrate their use.5. We can interpret the results of Experiments I and II as in the following sections.6. The next section summarizes the method in a from that is useful for arguments based on xxSummary1. This paper concludes with a discussion of future research consideration in section 5.2. Section 5 summarizes the results of this investigation.3. Section 5 gives the conclusions and future directions of research.4. Section 7 provides a summary and a discussion of some extensions of the paper.5. Finally, conclusions and future work are summarized6. The basic questions posed above are then discussed and conclusions are drawn.7. Section 7 is the conclusion of the paper.Abstract1. A basic problem in the design of xx is presented by the choice of a xx rate for the measurement of experimental variables.2. This paper examines a new measure of xx in xx based on fuzzy mathematics which overcomes the difficulties found in other xx measures.3. This paper describes a system for the analysis of the xx.4. The method involves the construction of xx from fuzzy relations.5. The procedure is useful in analyzing how groups reach a decision.6. The technique used is to employ a newly developed and versatile xx algorithm.7. The usefulness of xx is also considered.8. A brief methodology used in xx is discussed.9. The analysis is useful in xx and xx problem.10. A model is developed for a xx analysis using fuzzy matrices.11. Algorithms to combine these estimates and produce a xx are presented and justified.12. The use of the method is discussed and an example is given.13. Results of an experimental applications of this xx analysis procedure are given to illustrate the proposed technique.14. This paper analyses problems in15. This paper outlines the functions carried out by ...16. This paper includes an illustration of the ...17. This paper provides an overview and information useful for approaching18. Emphasis is placed on the construction of a criterion function by which the xx in achieving a hierarchical system of objectives are evaluated.19. The main emphasis is placed on the problem of xx20. Our proposed model is verified through experimental study.21. The experimental results reveal interesting examples of fuzzy phases of: xx, xx22. The compatibility of a project in terms of cost, and xx are likewise represented by linguistic variables.23. A didactic example is included to illustrate the computational procedure Chapter 1.Time1. Over the course of the past 30 years, .. has emerged form intuitive2. Technological revolutions have recently hit the industrial world3. The advent of ... systems for has had a significant impact on the4. The development of ... is explored5. During the past decade, the theory of fuzzy sets has developed in a variety of directions6.The concept of xx was investigated quite intensively in recent years7. There has been a turning point in ... methodology in accordance with the advent of ...8. A major concern in ... today is to continue to improve...9. A xx is a latecomer in the part representation arena.10. At the time of this writing, there is still no standard way of xx11. Although a lot of effort is being spent on improving these weaknesses, the efficient and effective method has yet to be developed.12. The pioneer work can be traced to xx [1965].13. To date, none of the methods developed is perfect and all are far from ready to be used in commercial systems.Objective / Goal / Purpose1. The purpose of the inference engine can be outlined as follows:2. The ultimate goal of the xx system is to allow the non experts to utilize the existing knowledge in the area of manual handling of loads, and to provide intelligent, computer aided instruction for xxx.3. The paper concerns the development of a xx4. The scope of this research lies in5. The main theme of the paper is the application of rule based decision making.6. These objectives are to be met with such thoroughness and confidence as to permit ...7. The objectives of the ... operations study are as follows:8. The primary purpose/consideration/objective of9. The ultimate goal of this concept is to provide10. The main objective of such a ... system is to11. The aim of this paper is to provide methods to construct such probability distribution.12. In order to achieve these objectives, an xx must meet the following requirements:13. In order to take advantage of their similarity14. more research is still required before final goal of ... can be completed15. In this trial, the objective is to generate...16. for the sake of concentrating on ... research issues17. A major goal of this report is to extend the utilization of a recently developed procedure for the xx.18. For an illustrative purpose, four well known OR problems are studied in presence of fuzzy data: xx.19. A major thrust of the paper is to discuss approaches and strategies for structuring ..methods20. This illustration points out the need to specify21. The ultimate goal is both descriptive and prescriptive.22. Chapter 2. Literature Review23. A wealth of information is to be found in the statistics literature, for example, regarding xx24. A considerable amount of research has been done .. during the last decade25. A great number of studies report on the treatment of uncertainties associated with xx.26. There is considerable amount of literature on planning27. However, these studies do not provide much attention to uncertainty in xx.28. Since then, the subject has been extensively explored and it is still under investigation as well in methodological aspects as in concrete applications.29. Many research studies have been carried out on this topic.30. Problem of xx draws recently more and more attention of system analysis.31. Attempts to resolve this dilemma have resulted in the development of32. Many complex processes unfortunately, do not yield to this design procedure and have, therefore, not yet been automated.33. Most of the methods developed so far are deterministic and /or probabilistic in nature.34. The central issue in all these studies is to35. The problem of xx has been studied by other investigators, however, these studies have been based upon classical statistical approaches.36. Applied ... techniques to37. Characterized the ... system as38. Developed an algorithm to39. Developed a system called ... which40. Uses an iterative algorithm to deduce41. Emphasized the need to42. Identifies six key issues surrounding high technology43. A comprehensive study of the... has been undertaken44. Much work has been reported recently in these filed45. Proposed/Presented/State that/Described/Illustrated/Indicated/Has shown / showed/Address/Highlights46. Point out that the problem of47. A study on ...was done / developed by []48. Previous work, such as [] and [], deal only with49. The approach taken by [] is50. The system developed by [] consists51. A paper relevant to this research was published by []52. []'s model requires consideration of...53. []' model draws attention to evolution in human development54. []'s model focuses on...55. Little research has been conducted in applying ... to56. The published information that is relevant to this research...57. This study further shows that58. Their work is based on the principle of59. More history of ... can be found in xx et al. [1979].60. Studies have been completed to established61. The ...studies indicated that62. Though application of xx in the filed of xx has proliferated in recent years, effort in analyzing xx, especially xx, is lacking. Problem / Issue / Question63. Unfortunately, real-world engineering problems such as manufacturing planning do not fit well with this narrowly defined model. They tend to span broad activities and require consideration of multiple aspects. 64. Remedy / solve / alleviate these problems67. ... is a difficult problem, yet to be adequately resolved68. Two major problems have yet to be addressed69. An unanswered question70. This problem in essence involves using x to obtain a solution.71. An additional research issue to be tackled is ....72. Some important issues in developing a ... system are discussed73. The three prime issues can be summarized:74. The situation leads to the problem of how to determine the ...75. There have been many attempts to76. It is expected to be serious barrier to77. It offers a simple solution in a limited domain for a complex。
最新研究生学术英语写作教程Unit-8-Writing-Abstract
Unit 8 Writing AbstractObjectives- Learn the purpose of writing an academic abstract- Get to understand different types of abstracts and the abstract elements- Understand features of academic English in writing an abstract- Learn how to write an academic abstract- Learn how to write key wordsContents- Teacher’s introduction- Reading and discussion:What is an academic abstract?What are the elements of an abstract?- Language focus: commonly used verbs and tenses; sentence patterns- Rewriting practice: understand different styles of academic abstracts- Rewriting practice: understand the elements of an academic abstract- Writing practice: write an abstract and key words based on the given material1.Reading Activity1.1 Pre-reading TaskAbstract is an important part of academic assignments, most often, reports and research papers. The abstract is the last item that you write, but the first thing people read when they want to have a quick overview of the whole paper. We suggest that you leave abstract writing to the end, because you will have a clearer picture of all your findings and conclusions.Before you learn the detailed steps to write an abstract, please discuss the following questions:What is the purpose of writing an abstract?What are the basic elements for an academic abstract?What language problems may you have in abstract writing? (For example: the wording problem, the tense problem and the voice problem, etc.)1.2Reading PassageSample Abstract 1This dissertation examines the impacts of social movements through a multi-layered study of the Mississippi Civil Rights Movement from its peak in the early 1960s through the early 1980s. By examining this historically important case, the writer clarifies the process by which movements transform social structures and the constraints when they try to do so. The time period studied includes the expansion of voting rights and gains in black political power, the desegregation of public schools and the emergence of white-flight academies, and the rise and fall of federal anti-poverty programs. Two major research strategies were used: (1) a quantitative analysis of county-level data and (2) three case studies. Data have been collected from archives, interviews, newspapers, and published reports. This dissertation challenges the argument that movements are inconsequential. Some view federal agencies, courts, political parties, or economic elites as the agents driving institutional change, but typically these groups acted in response to the leverage brought to bear by the civil rights movement. The Mississippi movement attempted to forge independent structures for sustaining challenges to local inequities and injustices. By propelling change in an array of local institutions, movement infrastructures had an enduring legacy in Mississippi.(Kenneth Tait Andrews, “‘Freedom is a constant struggle’: The dynamics and consequences of the Mississippi Civil Rights Movement, 1960-1984″ Ph.D. State University of New York at Stony Brook, 1997 DAI-A 59/02, p. 620, Aug 1998)1.3 Reading Comprehension1.3.1 What does the abstract talk about?1.3.2Decide how many elements this sample includes and how they function.2Language Focus2.1 Commonly used verbs and tenses in abstractsRead the following sample abstract and pay attention to the verbs used in it. Sample abstract 2Cybercrime –crime on the Internet –is of growing concern in the business community. Despite UK Government initiatives (such as BS7799) and growing sales in software solutions (e.g. anti-virus software), cyber attacks are on the increase. This dissertation focuses on ways to assess the effectiveness of current preventative measures to cybercrime and to understand why organizations continue to be vulnerable to cybercrime. This dissertation met these twin research aims through an extensive study of relevant literature and the implementation of practical research. The latter was carried out through a Case Study with Company XXX using semi-structured interviews with key I.T. security personnel. This research produced a number of key findings: recent surveys confirm a significant increase in the incidences of cybercrime and their impact on the business community but also the types of cybercrime (viruses, hacking, spam, identity theft, fraud, privacy issues, web vandalism, etc.); organizations lacked the security expertise to deal with cybercrime and so depended too much on readily available technical ways to combat cybercrime (and failing); organizations were not aware of Government recommendations on how to address Internet-based security issues; and Governments and law enforcement agencies tended to localize cybercrime, allocating scant resources to contributing to a global solution. The main conclusions drawn from this research were that current approaches to fighting cybercrime are deficient because they fail to embrace a holistic approach, instead opting for a narrow local software-based focus, and that a lack of communication between major stakeholders at local, national and international level has hindered security development. This research argues for a multi-pronged model to reduce incidences of cybercrime. It takes into account Risk-Assessment models, local management of company policies, implementation issues (including proper resourcing and review policies), the need for global support infrastructures, and a means of fostering communication networks.(/Dissertation_Abstract.htm)2.2 More verbs and sentences patterns2.2 Verb tenses in abstractsRead the abstract above again and check the tenses in the abstract.3Writing Practice3.1 Abstract writing practice3.1.1 Why do we care about the problem and the results? If the problem is not obviously "interesting", it might be better to put motivation first; but if your work is incremental progress on a problem that is widely recognized as important, then it is probably better to put the problem statement first to indicate which piece of the larger problem you are breaking off to work on. This section should include the importance of your work, the difficulty of the area, and the impact it might have if successful. Read the following paragraph and write down the Motivation in the blank.A review of groundwater remediation in use today shows that new techniques are required to solve the problems of pump and treat, containment and in-situ treatment. One such technique is the method that involves the use of permeable treatment walls. These methods use a reactive medium such as iron to remediate contaminated groundwater.3.1.2 What problem are you trying to solve? What is the scope of your work (a generalized approach, or for a specific situation)? Be careful not to use too much jargon. In some cases it is appropriate to put the problem statement before the motivation, but usually this only works if most readers already understand why the problem is important. Read the following paragraph and write the problem (aim) in the blank.Several methods of implementing this remediation strategy have been described. These methods include injection and trenching. The use of a funnel and gate system via a trench has been examined in detail using a groundwater modeling option of the FLAC program.3.1.3 How did you go about solving or making progress on the problem? Did you use simulation, analytic models, prototype construction, or analysis of field data for an actual product? What was the extent of your work (did you look at one application program or a hundred programs in twenty different programming languages?) What important variables did you control, ignore, or measure? Read the following paragraph and write the approach in the blank.The use of a funnel and gate system via a trench has been examined in detail using a groundwater modeling option of the FLAC program. The modeling involved an analysis of the effect of changing the lengths of the walls and gate, varying the permeability, and varying the number of gates.3.1.4 What is the answer? Specifically, most good computer architecture papers conclude that something is so many percent faster, cheaper, smaller, or otherwise better than something else. Put the result there, in numbers. Avoid vague, hand-waving results such as "very", "small", or "significant." If you must be vague, you are only given license to do so when you can talk about orders-of-magnitude improvement. There is a tension here in that you should not provide numbers that can be easily misinterpreted, but on the other hand, you do not have room for all the caveats. Read the following paragraph and write the result in the blank.The results showed that increasing the wall length, gate length and permeability increases the size of the plume captured. An important factor in designing the walls is the residence time of the water in the gate or the contact time of the contaminant with the reactive media.3.1.5 What are the implications of your answer? Is it going to change the world (unlikely), be a significant "win", be a nice hack, or simply serve as a road sign indicating that this path is a waste of time (all of the previous results are useful). Are your results general, potentially generalizable, or specific to a particular case? Read the following and write the conclusion in the blank:A sensitivity analysis has been conducted that shows that increasing the size of the capture zone decreases the residence time which will limit the design. The results of the modeling and sensitivity analysis are presented so that they can be used as an aid to the design of permeable treatment walls.3.2 The following is a structured abstract from a report examining the network legitimacy in China telecommunication market (Low, Johnston, and Wang 97). Read it and transfer it into an informative abstract.Abstract structurePurpose – The purpose of this paper is to establish the importance and approaches in securing an organization’s legitimacy from the network community of customers, suppliers and manufacturers, including private investors and state-owned institutions when marketing their products.Design/methodology/approach –The paper presents an inductive interpretative approach complemented by action-based research founded on inquiry and testing.Findings –The paper finds that the key to legitimacy success involves using legitimacy orientations to demonstrate commitment to the interests of constituents, acquiring legitimacy from them, but concurrently considering the central government’s influence on a firm’s legitimacy performance.Research limitations/implications –The multiple interactions proposed in this paper remain untested and might have to be modified pending further empirical testing and analysis.Practical implications –In China’s telecommunication market, a company’s legitimacy emanates first and foremost from the development and commercialization of innovative and creative technological solutions. This requires good, creative management of technological resource and activity links, connecting the company’s technology to network constituents which include local manufacturers, carriers, software developers, investors.Originality/value – This is the first published paper that examines the proposed interactions among legitimacy orientations, alignments, and performances from a “market-as-network” perspective in a dynamic, transitional Chinese telecommunication market.3.3Writing keywordsKeywords often stand alone after the Abstract. In choosing the key words, a wide choice of keywords increases the probability that a paper will be retrieved and read, thereby potentially improving citation counts and journal impacts. To ensure that your paper can be found and cited by as many readers as possible, as suggested by James Hartley, it might be worth considering selecting keywords from a series of categories such as Discipline (e.g. economic, chemistry, biomedical), Methods (e.g. experiment, case study, questionnaire, grounded theory), Data source (e.g. primary, secondary, tertiary students, senior citizens), Location (e.g. country, city, town, institution), Topic (e.g. air pollution, super-virus, earthquake). Such a selection of keywords allows the search engine, such as Google Advanced Scholar, to list your paper in the results no matter which of the above keywords the reader types in.The researchers sometimes have to trade-off between the keywords, particularly when they write for the journals that bound the number of keywords in the limit of 3~5. In this situation, choose the keywords from recent or often-cited titles close to your contribution. If you pick your keywords in this way, the searches that retrieve these articles will also retrieve yours. Consequently, the chances of your paper being read will increase. Read the above sample abstracts and write down the key words:4. Writing project4.1 Get prepared for writing an abstractBefore you write the Abstract section of your research paper, you need to make everything ready for your writing. The following steps may be helpful for your preparation.1) Identify the major objectives and conclusions.2) Identify phrases with keywords in the methods section.3) Identify the major results from the discussion or results section.4) Assemble the above information into a single paragraph.5) State your hypothesis or method used in the first sentence.6) Omit background information, literature review, and detailed description ofmethods.7) Remove extra words and phrases.8) Revise the paragraph so that the abstract conveys only the essential information.9) Check to see if it meets the guidelines of the targeted journal.10) Give the abstract to a colleague (preferably one who is not familiar with yourwork) and ask him/her whether it makes sense.Work in groups and discuss what other preparations you can make for writing an abstract section of your research paper.4.2 Outline an abstractWhen we outline an abstract, there are usually five major aliments to follow. The following sample paper is finished without the abstract and key words. Read the paper, find the statements concerned and fill in the blank after it.Sample paperGLOBAL MEGACITIES AND LOW CARBON: FROM CONCEPT PLANNING TO INTEGRATED MODELLINGPhil Jones, Simon Lannon, Robbert van Nouhuys, Hendrik RosenthalMega citiesIn 1950, 30% of the world’s population lived in cities. In 2000, it was 47%. By 2010 more than half of the world’s population will be living in cities. The total may even reach 60% by 2030 and possibly 85% by the middle of this century. Such rapidly increasing urbanization, particularly in developing countries, creates many opportunities and challenges.We are living in a globalized and changing world whereby increasingly we require wise use of human and natural resources. At the same time, we need to reduce the risk urbanization poses and enhance the quality of life for all those who live in, or are impacted by Megacities. Megacities are more than just large cities with populations of 10 million inhabitants or more. They are critical to national economies. Their scalecreates new dynamics, new complexity and new simultaneity of events and processes –physical, social and economic. They host highly efficient economic activities utilizing intense and complex interactions between different demographic, social, political, economic and ecological processes.Nations undergoing economic progress often generate rapid urbanization linked with considerable opportunities, as well as strong pressures for change accompanied by environmental degradation. In current times in the developing world, Megacities grow faster than ever before and much faster than their infrastructure can support. Traditionally this results in uncontrolled urban sprawl, high traffic volumes and congested transport systems, high concentrations of industrial production, ecological overload, unregulated and disparate land and property markets, insufficient housing development, excessive waste generation, loss of productivity, general economic constipation, degradation and decline.Over the past decades traditional Megacities have been suffering from inadequate representative governance, inhibiting spatial planning, building control, delivery of services (such as water supply, sewage disposal and energy distribution), and the establishment of general order (including security and disaster prevention). Existing administrations and their organizational structures may have been outgrown by the rapidly expanding city and may simply be unable to cope with the huge scale of their new responsibilities. On the other hand, megacities contain a rich mix of coexisting people and support systems when properly planned and managed. Groups with their own distinctive ethnic, community, cultural roots, lifestyles and social surroundings have opportunity to thrive and develop. Differences in economic development, social polarization, quality of infrastructure and governance are recognized and taken into account. The scale and dynamism of Megacities, coupled with complex interacting processes and the sheer concentration of human capital make them incubators of huge growth and innovation. Megacities are the focal points of globalization as well as the driving forces for development; they harbor a wide spectrum of human skill and potential, creativity, social interaction and cultural diversity.For Hanoi to develop within a rapid urbanization scenario it must look far ahead –not 20 years, not 50 years but 100 years –into the 22nd Century. The use of conventional planning and economic development guidelines have proven to be outdated, resulting in the risk of harboring pronounced poverty, social inequality, and aggravating rapid environmental degradation. Population density, if not managed, increases vulnerability to natural and man-made hazards. Thus, Megacities are both victims and producers of risk, if unmanaged and exposed to the global environmental, socio-economic and political changes to which they contribute.Megacities will be essential and efficient drivers of a nation’s gross domestic product, processes and activities. Megacities will be ideal places to drive activities and innovation to solve social, environmental, medical, socio-economic and political issues. For these reasons, Megacities are necessary and have potential to substantially contribute towards global justice and peace – and thereby prosperity.Low Carbon and Energy ModelingAspects of sustainable master planning that impact carbon and energy implications need to be understood to help inform concepts at the earliest stage of the design process. For example, the full benefits of reducing operating energy demand of buildings can only be realized if the energy supply can respond to the reduced demand, which includes the additional benefits of reducing the energy supply infrastructure, which in turn reduces its embodied energy. Likewise, if a low (or zero) carbon energy supply is to be used, for example, renewable energy, this is easier to achieve if first the energy demand is reduced. Also, as the operating energy performance of buildings is improved the carbon dioxide emissions associated with the operation of the building, for heating, cooling, lighting, etc., becomes of the same order as the embodied energy used in construction and fit-out of the building and its infra-structure. So a balanced approach across energy demand and supply infrastructure, operating energy and embodied energy, is needed to achieve optimum performance.This paper describes how the aspects of low carbon planning and design (i.e. operating energy use, embodied energy associated with buildings, energy supply infrastructures, and other infrastructures such as transport, waste, water, sewage, etc.) can be assessed using urban scale modeling, namely EEP-Urban, at a whole city and building plot level. In particular, it explores how the reduction in energy supply infrastructure together with reduced energy demand can lead to reductions in carbon dioxide emissions associated with both operating and embodied energy. The concept of the Megacity in the context of Hanoi in 2110 is used to illustrate the model.The Concept of Metabolic Super ClustersHanoi in 2110 will feature super tall skyscrapers, elevated connectors and railways, nodal communication networks, as well as electrical and energy corridors. Vertical neighborhoods, where people live, shop, relax and work, are built on and above this surface. Built structures are not just individual towers standing independent from another but instead are interlinked and inter-dependent to form an urban spatial organization that allows for vertical connectivity.The urban model proposes 1 million people on a 1 square kilometer floor plate, hence called a Super Cluster. Under current suburban density standards a similar population would require in the order of 100 square kilometers. Thus, this vision for Hanoi in 2110 saves 99% of land for other uses, most notably conservation of ecological functions and provides food, leisure, material and energy support systems for the city thereby localizing the ecological footprint of the city.Another distinct aspect of Hanoi in 2110 is that it does not have static building functions. Instead, land use layers, building envelopes and orientations change over time – hourly, daily, weekly, monthly, yearly – to optimize performance efficiencies, therefore becoming a Metabolic Super Cluster. It is envisaged that Hanoi by the end of this century will consist of 30 metabolic super clusters in addition to its traditional urban city centre.Concentrated compact development will enhance the quality of life for urban dwellers because all infrastructures, environmentally damaging and other undesirablesurface activities are located underground or integrated into the vertical structure, thereby significantly improving the quality of living space at the ground, open-air level. Underground space may also provide a safer environment for some public and commercial activities as well as providing shelter from inclement weather conditions. This may prove to be essential for infrastructure in particular, given the predicted impacts associated with climate change. Elevated multi-level connectors between building clusters are converted into common corridors with public amenities, farms and open space.Quality of life depends on individual perceptions, attitudes, aspirations and value systems. These differ with age, ethnicity, culture and religion, as well as lifestyles, education and cultural background. An individual’s priorities and attitudes to life depend heavily upon socio-economic background and cultural environment. Historic places, cultural sites or public spaces may give Megacities a certain unique identity, heritage, and authenticity. As a result, such spatial capital contributes to social cohesion and makes people feel at home.Nevertheless, the general opinion may be that the quality of life for many residents in Megacities would be low – for rich and poor alike. Air, water and soil pollution, water and energy supply shortages, traffic congestion, environmental health problems, limited green spaces, poverty and malnutrition, social security and public safety problems place many burdens and restrictions on people.The Megacity of the future has adapted to greater diversity in socio-cultural circumstances by including and enhancing the often widespread and dynamic informal activities that enrich such communities. Further development of new visions and innovative management tools are now urgently needed in order to enhance quality of life and create cohesive communities.Urban governance and management is one of the key success factors of any global Megacity. As society and aspirations evolve over time, the city has to be designed to adapt to change. Utopian cities built around fixed ideologies have never worked. Megacities need to be versatile in order to adapt.The main challenges for a Megacity in terms of urban governance are: dealing with the speed of change with intelligent urban infrastructure systems; eradicating social exclusion; and introducing proper forms of urban governance.Way ForwardWhether or not 1 million people are appropriate for a 1 km2 super cluster remains to be seen. The optimum density for sustainability, land use and quality of life may be less and will vary with global location. The above approach is essential to inform the design of high rise high density Megacities if they are to realize their full potential for providing sustainable healthy zero carbon cities of the future that can co-exist in a sustainable way with their neighboring rural areas.4.3 According to the above table, draft an abstract and keywords for the sample paper. Abstract:Key words:5.Final Checklistbackground, purpose, findings, conclusions, recommendations and follow strictly the chronology of the report/papers.∙Avoid excessive use of jargon, and exaggerative language∙Keep within the specified word limit. Most institutions will have their own "house rules" as to the length of the abstract. The abstract should stand alone and be able to be understood without reference to citations,∙Ensure the abstract contains all your key words (for the searchable databases). ∙Add no new information but simply summarize the report/papers. Be intelligible to a wide audience。
国家社科基金项目 英语
Unlocking the Secrets of Successful Social Science Research:Insights from National Social Science FoundationProjectsAre you interested in conducting cutting-edge social science research?Look no further than the National Social Science Foundation projects currently underway in China. These exciting projects cover a wide range of topics,from climate change and urbanization to poverty and inequality. But what do these projects tell us about the key factors for success in social science research?One important takeaway is the importance of interdisciplinary collaborations.Many of the current National Social Science Foundation projects involve teams of researchers from different disciplines,such as sociology, economics,and geography.By bringing together experts with diverse backgrounds and perspectives,these projects are able to tackle complex social issues from multiple angles, producing more comprehensive and nuanced results.Another lesson from these projects is the value of innovative research methods.Social science research often involves collecting data from surveys,interviews,or other sources.However,the National Social Science Foundation projects also utilize cutting-edge methods such as big data analysis,geospatial modeling,and experimental designs.By using these methods,researchers are better able to capturethe complexity of real-world social phenomena,leading tomore accurate and insightful findings.Finally,these projects highlight the importance of engaging with local communities and policymakers.Successful social science research should not exist in a vacuum,but rather should strive to have real-world impact.The National Social Science Foundation projects actively involve local communities in the research process,consulting with them on research questions and sharing findings to inform policy decisions.This engagement helps to ensure that research has practical applications and can make a positive difference in people's lives.Overall,the National Social Science Foundation projects offer valuable insights for anyone interested in conducting impactful social science research.By promotinginterdisciplinary collaborations,innovative research methods,and community engagement,these projects demonstrate the key factors for success in addressing complex social issues.。
我的理想工作成为一名建筑师英语作文
我的理想工作成为一名建筑师英语作文全文共3篇示例，供读者参考篇1My Dream Job: To Become an ArchitectEver since I was a little kid, I have always been fascinated by buildings and structures. Whether it was admiring the unique designs of skyscrapers in the city or marveling at the intricate details of historical buildings, I have always had a keen interest in architecture. As I grew older, I realized that my passion for architecture was not just a passing phase, but rather a calling that I wanted to pursue as a career. That is why my dream job is to become an architect.To me, architecture is not just about designing buildings; it is about creating spaces that inspire and uplift people. It is about combining aesthetics with functionality, and creating structures that stand the test of time. I believe that as an architect, I would have the opportunity to shape the way people live, work, and interact with their environment. I see architecture as a form of art that has the power to transform communities and enrich lives.In order to pursue my dream of becoming an architect, I am currently studying architecture at university. I am constantly learning about different architectural styles, techniques, and principles. I am honing my skills in drawing, drafting, and modeling, and I am always looking for ways to improve and expand my knowledge. I am also gaining hands-on experience through internships and work opportunities in architectural firms.I believe that with dedication, hard work, and perseverance, I can achieve my goal of becoming a successful architect.One of the reasons why I am so passionate about architecture is because it allows me to combine my love for creativity with my desire to make a positive impact on the world.I believe that architecture has the power to address important social, environmental, and cultural issues. As an architect, I want to design sustainable, green buildings that minimize their environmental impact and promote energy efficiency. I want to create spaces that are accessible and inclusive for people of all ages and abilities. I want to preserve and celebrate the historical and cultural heritage of communities by incorporating traditional design elements into my work. In short, I want to use architecture as a tool for positive change.Furthermore, I am inspired by the great architects of the past and present, who have pushed the boundaries of design and innovation. Architects like Frank Lloyd Wright, Zaha Hadid, and Renzo Piano have shown me that architecture is a constantly evolving field that rewards creativity, innovation, and vision. Their iconic buildings have left a lasting impression on me, and have inspired me to strive for excellence in my own work. I believe that by studying the works of these master architects, I can learn from their techniques and insights, and apply them to my own designs.In conclusion, my dream job is to become an architect because it allows me to combine my passion for creativity with my desire to make a positive impact on the world. I believe that through architecture, I can create beautiful, functional spaces that enhance the lives of people and communities. I am dedicated to pursuing my dream of becoming an architect, and I am committed to working hard, learning continuously, and pushing myself to new heights. I know that the road to becoming an architect is challenging and competitive, but I am willing to put in the effort and dedication required to achieve my goal. I am excited to see where my journey in architecture will take me, and I am confident that I have the skills, passion, and determinationto succeed in this field. Architecture is not just a career for me; it is my calling, my passion, and my dream.篇2My Dream Job of Becoming an ArchitectAs a child, I was always fascinated by buildings. I would spend hours drawing floor plans of imaginary homes and skyscrapers, dreaming of one day creating structures that would stand the test of time. As I grew older, my passion for architecture only deepened, and I knew that I wanted to pursue a career in this field.My dream job is to become an architect. I envision myself designing buildings that not only serve a functional purpose but also inspire and uplift those who interact with them. I want to create spaces that are both aesthetically pleasing and sustainable, blending form and function in a way that enhances the lives of those who inhabit them.To achieve my goal of becoming an architect, I have dedicated myself to my studies. I have pursued a degree in architecture, learning about design principles, construction techniques, and sustainable building practices. I have also sought out internships and work opportunities in architecturalfirms, gaining practical experience in the field and honing my skills.In addition to my academic and professional pursuits, I have also taken the time to explore different architectural styles and movements. I have studied the works of renowned architects such as Frank Lloyd Wright, Zaha Hadid, and Renzo Piano, drawing inspiration from their innovative designs and groundbreaking ideas. I have also traveled to different cities around the world to see firsthand the impact that architecture can have on a community.As an architect, I hope to use my talents to create buildings that not only meet the needs of their occupants but also contribute to the greater good. I believe that architecture has the power to shape the world around us, influencing how we live, work, and interact with our environment. I want to be a part of this transformative process, using my skills to design buildings that are both beautiful and functional, sustainable and innovative.In conclusion, my dream job is to become an architect. I am passionate about creating structures that inspire and uplift, that blend form and function in a way that enhances the lives of those who interact with them. I am committed to pursuing this dreamwith dedication and hard work, and I am confident that I will one day achieve my goal of becoming a successful architect.篇3My Ideal Job: Becoming an ArchitectIntroductionAs a child, I have always been fascinated by buildings. The way that they are designed and constructed has always intrigued me. I remember spending hours playing with building blocks and creating my own miniature cities. This passion for architecture has stayed with me throughout my life and has led me to dream of becoming an architect.Why I Want to Become an ArchitectThere are several reasons why I want to pursue a career in architecture. Firstly, I believe that architecture is a powerful form of art that can have a profound impact on people's lives. The buildings that we inhabit, work in, and visit on a daily basis have the ability to shape our experiences and define our surroundings. As an architect, I would love to be able to create spaces that inspire, excite, and make a positive difference in people's lives.Secondly, I am drawn to the creative aspect of architecture. I love the idea of being able to combine my love for design, engineering, and art in a single profession. The process of conceptualizing a building, drawing up plans, and seeing it come to life is something that I find incredibly rewarding. I am always excited by the challenge of solving complex problems and coming up with innovative solutions to design challenges.Finally, I am passionate about sustainability and the environment. I believe that architects have a responsibility to design buildings that are not only beautiful and functional but also environmentally conscious. I am inspired by architects who are leading the way in sustainable design, and I would love to be able to contribute to creating a more sustainable future through my work.My Career Goals as an ArchitectAs an aspiring architect, my ultimate goal is to become a successful and respected professional in the field. I envision myself working on a wide range of projects, from residential homes to commercial buildings to public spaces. I would love to collaborate with other professionals, such as engineers, contractors, and interior designers, to create holistic andwell-designed spaces.I also hope to specialize in sustainable design and green building practices. I want to stay at the forefront of innovative technologies and materials that can make buildings more energy-efficient and environmentally friendly. I aspire to be a leader in the sustainable design movement and to be able to influence the industry towards more sustainable practices.In addition, I am also interested in urban planning and community development. I would love to work on projects that have a positive impact on the communities they serve, such as affordable housing, public parks, and community centers. I believe that architecture has the power to bring people together and create vibrant and inclusive neighborhoods.ConclusionIn conclusion, my dream job is to become an architect. I am passionate about design, creativity, and sustainability, and I believe that architecture is the perfect profession for me to combine these interests. I am excited about the challenges and opportunities that lie ahead in my journey towards becoming an architect, and I am committed to working hard to achieve my goals. I cannot wait to begin my career in architecture and to start making a positive impact on the world through my work.。
人体骨肌系统的整体生物力学建模与仿真分析研究中国力学虚拟人系统集成方法与实现
人体骨肌系统的整体生物力学建模与仿真分析研究中国力学虚拟人系统集成方法与实现一、本文概述Overview of this article随着生物医学工程、计算机仿真技术及力学研究的不断深入，人体骨肌系统的生物力学建模与仿真分析在医疗、康复、体育训练及人体工程学等领域的应用越来越广泛。
其中，中国力学虚拟人系统作为一种集成多源数据、高精度人体模型与仿真技术的创新平台，为深入研究和理解人体骨肌系统的生物力学特性提供了强大的工具。
本文旨在探讨中国力学虚拟人系统集成方法与实现，通过对人体骨肌系统的整体生物力学建模与仿真分析，为相关领域的研究与实践提供理论支持和技术指导。
With the continuous deepening of biomedical engineering, computer simulation technology, and mechanical research, the biomechanical modeling and simulation analysis of the human skeletal muscle system are increasingly widely used in fields such as medicine, rehabilitation, sports training, and ergonomics. Among them, the Chinese Mechanical Virtual HumanSystem, as an innovative platform that integrates multi-source data, high-precision human models and simulation technology, provides a powerful tool for in-depth research and understanding of the biomechanical characteristics of the human skeletal muscle system. This article aims to explore the integration method and implementation of Chinese mechanical virtual human system, and provide theoretical support and technical guidance for research and practice in related fields through the overall biomechanical modeling and simulation analysis of the human skeletal muscle system.本文首先介绍了人体骨肌系统生物力学建模的基本原理和方法，包括骨骼结构、肌肉力学特性及关节运动学等方面的建模技术。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Jian Sun
Advanced Technology Center Rockwell Collins, Inc. 400 Collins Road NE, Cedar Rapids, Iowa 52498 E-mail:jsun@
Abstract - This pa-cr addresses modeling and practical design issues for PWM converterswith average current contro1.A straightforward averaged modeling method is proposed, and the resulting models are shown to be accurate enough for practical design purpose. Limitations of previously published models that incorporate sampling effect are discussed. The proposed averaged model is then applied for stability analysis and control design. In particular, conditions under which switching instability may occur are identified,and design method that avoids the instability problem is presented. The proposed modeling and design methods are demonstrated and further validated by a prototype synchronousswitch buckconverterwith 5V input and 2V output
and
Richard M. Bass
School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta, Georgia 30332-0250 E-mail: bAverage current control [l] has been frequently used for controlling DC/DC as well as single-phase power factor correction (PFC) converters. Compared to peak current control, average current control has the following advantages: 1) no needs for an extemal compensation ramp, 2) increased current loop gain in DC and at low frequencies,and 3) improved immunity to noise in the sensed current signal. The increased DC and lowfrequency gain of the current loop is especially attractive for single-phase PFC applications using boost-derived topologies, where it is desirable that the average, rather than the peak of the inductor current follows precisely a sinusoidal reference. High current loop gain in DC and at low frequencies is also a desirable feature for buck-derived converters used as current sources. Modeling and design of average current control has been the subject of several technical papers and seminar notes [l-31. Detailed design guidelines for the current compensator are provided in [l], which is a valuable reference for practicing engineers. In particular, optimum gain of the current compensator that maximizes current loop gain, yet avoids current loop subharmonic oscillationproblem, is suggested in [ 11 for different topologies. However, it was found that this optimum gain often leads to high switching-frequency ripple in the current compensator output when the converter operates with narrow duty cycle. As a result, switching instability may occur. Small-signal models for average current controlled PWM convertershave been presented in [2] and [3]. These models have the following limitations: 1) They are all small-signal models, hence cannot be used for large-signalanalysis; 2) Sampling effect
is incorporated in certain form as a means to improve model accuracy, but adds complexity to the model. Inclusion of the sampling effect has proven to be valuable for improving the accuracy of averaged models for peak current control [4], but its effect in average current control is arguable. In terms of PWM process, average current control more closely resembles voltagemode control (for both use an artificial triangular waveform for P W ) than peak current control. State-space averaged models without incorporating sampling effect have proven to be accurate up to half of the switching frequency in the case of voltage-mode controlled PWM converters. Considering this, it is legitimate to ask why the sampling effect needs to be considered in average current control, but not in voltage-mode control? In this paper, straightforward state-space averaging is reapplied to average current controlled PWM converter (Section 11). In this approach, a complete averaged model is obtained by combining the state-space averaged model of converter power stage with the model of the current compensator. The comparator that generates.the PWM signal is simply modeled as a constant gain; the arguable, often confusing sampling effect is not considered. It will be shown that the resulting model is simpler, valid for large signal, and in fact also more accurate than previous models that take into account the sampling effect. Possible degrading of model accuracy under large ripple conditions is discussed, and it is shown that inclusion of sampling effect doesn’t improve model accuracy in that case. Section IV of the paper deals with current compensator design and switching instability problem. Conditions under which switching instability may occur are identified, and limitations of previous design method are discussed from this prospect. New design method that avoids the instability problem is presented. Finally, in Section V, a 5V-inputDV-output buck converter is used as an example to demonstrate the proposed design method. The buck converter uses synchronous switch to achieve high efficiency, and the control is implemented using a Unitrode control chip. Experimental results are presented as well. 11. AVERAGED MODELING The average current control scheme is depicted in Fig. 1. Principle of this control method is as follows [I]: The inductor current, iL, of the converter is sensed by a resistor, R,, and compared with voltage vc that represents the required average