Gloria Sol Top Models of Metart.com

This book presents the methodology of complex activity with a set of interconnected mathematical models that describe the processes of technology design, adoption and use.

Generic group algorithms solve computational problems defined over algebraic groups without exploiting properties of a particular representation of group elements. This is modeled by treating the group as a black-box. The fact that a computational problem cannot be solved by a reasonably restricted class of algorithms may be seen as support towards the conjecture that the problem is also hard in the classical Turing machine model. Moreover, a lower complexity bound for certain algorithms is a helpful insight for the search for cryptanalytic algorithms.

This volume reports the results of a symposium held in Heidelberg during the International Sedimentological Congress in late August and early September, 1971. The symposium, co­ sponsored by the International Association for Mathematical Geology, entertained the subject, "Mathematical Models of Sedimentary Processes. " The subject is most appropriate because sedimentologists have long been concerned with processes and mechanisms of sedi­ ment dispersal. Much effort has gone into building physical models such as flumes, stream tables, wave tanks, wind tunnels, etc. , to help understand sedimentological processes.

The purpose of this book is to describe in sufficient detail the mathematical models of hysteresis nonlinearities with "nonlocal memories. " The distinct feature of these nonlinearities is that their future states depend on past histories of input variations. It turns out that memories of hysteresis nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteresis nonlinearities. Thus, special mathematical tools are needed to describe nonlocal selective memories of hysteresis nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. The book is primarily concerned with Preisach-type models of hysteresis.

Computer algebra systems are revolutionizing the teaching, the learning, and the exploration of science. Not only can students and researchers work through mathematical models more efficiently and with fewer errors than with pencil and paper, they can also easily explore, both analytically and numerically, more complex and computationally intensive models.