Modelování a simulace dynamických systémů

From Forbes T. Brown. Engineering System Dynamics: A Unified Graph-Centered Approach. 2nd Ed. Taylor and Francis, 2007. Pages 7 and 8.

Does the prospect of learning the material in a textbook like this, with its seemingly endless drawings and equations, seem daunting? The substance of this book, like many others, represents just a few patterns that theoretically ought to be expressible in a small fraction of the space. The problem is that this author, like all the others, just doesn’t know how to make this work. It is up to the reader to compress the exposition down to its essential meaning. Then, and only then, is the subject truly manageable and useful. A few students manage this naturally. The following remarks are directed largely to the remaining majority.

Some subjects cannot be so distilled, such as uncorrelated lists of facts, or texts that demand memorization. There is little of this sort in this book, although some of the mathematics in Chapters 4 and 7 comes close. A good literal memory is not needed, particularly for the core modeling concepts, and may in fact get in the way. If you can’t remember much of anything verbatim, you’re forced to create a mental pattern to represent the information, which is the desired result. Some patterns are logical, some relational, and some visual. Different people have different profiles of intelligences, and therefore develop different patterns, and compensate for weaknesses in different ways.

This textbook aims to arm you to address a broad range of engineering situations by placing them within a. simple unified structure. Engineering has long had a tightly integrated core, which when understood allowed the engineer to extend his or her competence to new areas. Nevertheless, there used to be many specialists in various sub-disciplines, such as solid mechanics, fluid mechanics and heat transfer. Today, the roles of most of these specialists, except at the highest levels, have been replaced by commercially available software. This means that the successful engineer must be even more of a generalist, for he or she cannot take advantage of the software without a basic understanding of its meaning. He or she must be more like an orchestra conductor or even a composer, rather than the flutist or the cellist.

Your generation has made important advances in social and communication skills. At the same time old professors are keenly aware that certain basic technical skills have eroded. They wish to inspire the young with what they know is possible. The change has been caused partly by the explosion of information technology. Also, modern parents tend to fill their children’s time with organized activities, believing that this will help their general education, advance their credentials, keep them out of trouble, and permit mother to work. This enhances socialization but fails to provide the free time and even boredom that is necessary for the development of independent thought and creativity. A particular decline has occurred in spatial visualization skills, due largely to schools discontinuing courses in drawing and descriptive geometry in the vain hope that the computer graphics would fill the need. Symptoms of the erosion include less attention to textbooks which are even sold at the end of the semester, greater reliance on the instructor, asking where to find the solution to a problem rather than how to solve it, conceiving of engineering as a group of loosely related procedures, struggling with drawing or spatial relationships, and expecting quick gratification.

The problem-specific mode of learning, which emphasizes detailed prescriptions for solving specific problem types through the examination of the solutions of numerous sample problems, has unfortunately ascended. The student tends to view these prescriptions as the information need for success, rather than the relatively simple underlying concepts that are gained only through a more circumspect approach. Real-world engineering covers a thousand times more situations than possibly could be addressed by sample problems. The breadth of the problems in this text may help convince you of the futility of reliance on superficial procedures, despite your earlier experience.

The alternative problem-general learning mode stores the information needed for success in an integrated network of basic concepts and procedures. Case studies, solved problems, guided problems and assigned problems are not definitive patterns to be imitated, but are suggestive illustrations that help you develop your integrated network. A small set of concepts casts myriad shadows in printed solutions to relevant problems. It is inefficient to infer reality solely from its shadows. You must, rather, recognize what basic concepts apply to your real-life problems. In this information age there are many ways you can find the details. The variety of situations addressable through the learning mode grows exponentially with the number of the core concepts and procedures understood. Further, the structure becomes an increasingly redundant network of ideas. If some element is forgotten, a detour around the flaw usually can be found, and the flaw itself often can be repaired without recourse to outside information. It may seem that the amount of information you need to recall actually decreases with experience. Engineering becomes heady stuff. ls your pleasure growing with each successive course'?

This book complements its direct presentation of topics with four different types of problems: case studies, numbered and highlighted examples, guided problems and assigned problems. Case studies typically introduce and illustrate new ideas and should be viewed as integral parts of the text. The numbered examples, on the other hand, are mostly sample problems that demonstrate application of the basic concepts and procedures. They logically may be skipped, although you should find most of them useful. The "guided problems” in this text are a kind of compromise; they start with a problem statement and proceed with a list of “suggested steps" that is less than a unique prescription for a solution but is intended to relate the solution to the core concepts and procedures. You may then compare your solution with one given at the end of the section. Each guided problem exists for a purpose, which is briefly suggested at the outset. (Some guided problems are advanced or optional.) You defeat their primary purpose by looking at the given solution before attempting to create your own. Even when you fail to produce a solution, you will usually benefit from the attempt.

Your challenge is real, but the opportunities for excelling are great. Focus on underlying concepts rather than the nitty gritty. This takes courage at first, because you may fear that your colleagues who memorize stuff will get the upper hand during exams. Later, however, it will give you bracing self-confidence. The concepts are in fact few, while the nitty gritty is endless. Regard this and other technical textbooks as your primary professional tools; never sell one, for while you will forget the details of this formula or that diagram, you will likely remember what book it’s in and probably whether it’s on a right or a left facing page. And I mean decades later. Familiar textbooks become an extension of your intellect in ways the internet cannot replace. Whether the instructor is good or not becomes a minor factor; he or she hopefully imparts some inspiration and suggests what is central but cannot convey the big picture nearly as completely, efficiently or permanently as a good textbook.