As a stand-alone volume, Transistor Circuits For Spacecraft Power System presents numerous transistor circuits and building blocks associated with power electronics in general, and examines the major subsystem components for solar-based spacecraft power systems. The technique and concept, of "continuity of states" for nonlinear circuits handling power transfer under cyclic excitation is introduced in Part I and further developed throughout the book. This powerful technique employing matrix formulation bypasses eigen-transients and yields steady-state responses rapidly. Closed-loop treatments are also given for large-scale linear circuits, many closed-form solutions for control loop-gain, conducted susceptibility, output impedance, etc. are covered. Extensive mathematical procedures are retained to highlight the importance of analytical flows. The author also reviews the evolution of solar-based spacecraft power systems; introduces modes of operations: discharge (boost), shunt, and charge; and covers pulse-width-modulated (PWM) boost power converter for both DC and AC conditions. A configuration tree for shunt mode operation is conceived. Based on the configuration tree, the best topologies, sequential PWM shunt and ripple-regulated free-running shunt, are intensively examined and formulated. Transistor Circuits For Spacecraft Power System provides important information for understanding the relationship between earthbound semiconductor circuits and space borne vehicles.

Progressive reductions in vehicle emission requirements have forced the automotive industry to invest in research and development of alternative control strategies. Continual control action exerted by a dedicated electronic control unit ensures that best performance in terms of pollutant emissions and power density is married with driveability and diagnostics. Gasoline direct injection (GDI) engine technology is a way to attain these goals. This brief describes the functioning of a GDI engine equipped with a common rail (CR) system, and the devices necessary to run test-bench experiments in detail. The text should prove instructive to researchers in engine control and students are recommended to this brief as their first approach to this technology. Later chapters of the brief relate an innovative strategy designed to assist with the engine management system; injection pressure regulation for fuel pressure stabilization in the CR fuel line is proposed and validated by experiment. The resulting control scheme is composed of a feedback integral action and a static model-based feed-forward action, the gains of which are scheduled as a function of fundamental plant parameters. The tuning of closed-loop performance is supported by an analysis of the phase-margin and the sensitivity function. Experimental results confirm the effectiveness of the control algorithm in regulating the mean-value rail pressure independently from engine working conditions (engine speed and time of injection) with limited design effort.

The IUTAM Symposium on Three-dimensional Turbulent Boundary Layers was suggested by the Gesellschaft fur Angewandte Mathe- matik (GAMM) and sponsored by the International Union of theor- etical and Applied Mechanics. The symposium was organized by H.H. Fernholz (Hermann-Fottinger-Institut fur Thermo- und Fluiddynamik der Technischen Universitat Berlin) and E. Krause (Aerodynamisches Institut der RWTH Aachen). After two success- ful Euromech Colloquia on the same topic in Berlin 1972 and Trondheim 1975 the organizers felt that another meeting should be convened, this time with participants from inside and out- side Europe. The aim of the symposium has been to bring together scientists who are actively engaged in boundary layer research, both ex- perimental and theoretical. The scope of the meeting encompass- ed incompressible and compressible three-dimensional turbulent boundary layers. Special emphasis was laid on economical cal- culation methods, on measurements of fluctuating quantities and on measuring techniques designed for and applied success- fully to three-dimensional boundary layers. From among thirty-four papers submitted for presentation, twenty- six contributions of twenty-five minutes each were selected by the European mernbers of the Scientific Committee. Furthermore there were four invited lectures of forty-five minutes. Short discussions were held directly after each presentation with a long discussion period at the end of each day. The final dis- cussion on the last day of the symposium was recorded on tape and is presented in a slightly shortened version as the last contribution in this volume.

This volume is a compendium of papers presented during an Advanced Seminar on Air Traffic Control (ATC) that took place in Capri, Italy on October 28-31, 1991. The Seminar was' organized by the Progetto Finalizzato Trasporti of the Italian National Research Council. The papers presented in the Seminar dealt with a wide range of topics which are currently important in ATC. For example, there were papers on such subjects as recent developments in primary and secondary radar technologies, communications networks and protocols, and the future uses of satellite-based communications, navigation and surveillance in ATC. However, all the papers contained in the volume were selected exclusively from that set of papers that addressed some aspect of the main area of emphasis in the Seminar, namely massive data-processing requirements and computer intensive problems in ATC. Data-processing requirements in A TC have grown enormously over the years. Obviously, the rapid increase in air traffic volumes in most of the world is one of the factors that has contributed to this growth. However, two other developments have contributed much more significantly: first, the ATC system now collects (mostly automatically) immensely more "information per flight" than in the past; and, second, as the system's complexity increases and as it becomes more tightly interconnected geographically, so grows the need to communicate, process and "filter" the data presented to the system's various components."

This volume is a compendium of papers presented during the second TRlennal Symposium on Transportation ANalysis (TRISTAN II) that took place in Capri, Italy on June 23-28, 1994. The Symposium was organized by the Progetto Finalizzato Trasporti and the Istituto di Analisi dei Sistemi ed Informatica of the Italian National Research Council jointly with the Italian Operations Research Society. The purpose of this kind of meetings is to periodically allow an exchange of views and findings by scientists in the field of transportation analysis methods and tools. Therefore, the papers presented dealt with a wide range of topics and cover the different aspects of transportation analysis. The material contained in this book gives particular emphasis to the development of mathematical modelling and algorithms. This development is due to the evolution of digital computers and the continuous increase of the computing power. In fact the need of solving large scale problems (crew scheduling, network traffic control, pollution monitoring and control, . etc ... ) involves in some case, thousands of variables and therefore sophisticated mathematical models and computational algorithms

Exploiting new advanced structures and electromechanical systems, e. g. , adaptive structures, high-precision systems, micro electromechanical systems, distributed sensors/actuators, precision manipulation and controls, etc. , has been becoming one of the mainstream research and development activities (structure & motion) in recent years. These new systems and devices could bring a new technological revolution in modern industries and further, directly or indirectly, impact human life. In the search for and research in innovative technologies, it is proved that piezoelectric materials are very versatile in both sensor and actuator applications. Consequently, piezoelectric technology has been widely applied to a large number of industrial applications and devices, varying from thin-film micro sensors/actuators to large space structures in addition to those relatively conventional applications, e. g. , sensors, actuators, hydrophones, precision manipulators, mobile robots, micro motors, etc. There have been a few books on piezoelectricity published in the past; however, a unified presentation of piezoelectric shells and distributed senSing/control applications is still lacking. This book is intended to fill the gap and to pro~de practising engineers and researchers with an introduction to advanced piezoelectric shell theories and distributed sensor/actuator technologies in structural identification and control. This book represents a collection of the author's recent research and development on piezoelectric shells and related applications to distributed measurement and control of continuaj it reflects six best-paper awards, including [ xviii] * Contents. two ASME Best-Paper Awards in recent years.

This book includes the proceedings of the Workshop held in Madrid, April 1999 to celebrate 2 years of successful operation of the first Spanish small scientific satellite in orbit. It contains discussions about the overall philosophy of small mission programs, the design of the satellite and its payload as well as the most relevant scientific outcome of the mission. Also included are additional contributions to the workshop, which are of importance to Minisat 01 in order to put its results within context. Finally, the future of small missions for space sciences is reviewed together with the main technological challenges for new studies. Out of the technological and scientific results of Minisat 01, the measurement of the EUV airglow spectrum and the flux of some stars in the same range can be highlighted together with the dismiss of the massive neutrino decay theory. The high-energy experiment analyzed the characterization of the radiation environment in LEO and the behaviour of different kind of detectors, as well as the use of coded masks for imaging and the measurement of some specific sources. The book's level is intended for specialists in EUV and Hard X-Ray astrophysicists as well as for engineers and technicians involved in space science experiments and missions.

This volume is the result of an international collaboration, which started with a conference at Smadalaro Gfrrd in Sweden. The workshop was supported by the National Science Foundation of the USA (INT-9215114) and by the Swedish National Road Administration, the Swedish Council for Building Research, the Swedish Transport and Communications Research Board and the Swedish Council for Planning and Coordination of Research. This support is gratefully acknow ledged. The collaboration started as a bilateral u.S.-Swedish endeavour but was soon widened to other scholars in Europe, Asia, Australia and South-America. Network Infrastructure and the Urban Environment is a policy area of growing importance. Sustainable cities and sustainable transport systems are necessary for attaining a sustainable development. The research and policy field, represented in this volume, comprises a number of challenging contrasts: - the contrast between infrastructure investments, mobility and environmental sustainability; - the contrast between policy contexts, modelling traditions and available decision support systems in various parts of the world; - the contrast between available best practice methods and the majority of models applied in planning; the contrast between static models of cross-sectionary equilibria and dynamic models of disequilibrium adjustments; and the contrast between state-of-the-art operationalland-use/transport models and new demands for land-use/transportlenvironment models due to changing policy contexts. Bridging some of these gaps constitutes important research tasks, that are discussed in the twenty-two chapters of this book. A number of emerging research directions are identified in the introduction and summary chapter."

The emergence of civil aviation as a means of mass transportation is primarily due to the large scale construction of jet airplanes in the past 30 years or so. A large number of these jet airplanes is currently operating at or beyond their designed fatigue lives. Thus, the structural integrity of these aging airplanes has become an issue of major concern to all nations of the world. To bring the needed technical and research focus on the issues involved in the life-enhancement and safety-assurance of aging airplanes, the Federal Aviation Administration sponsored a symposium in Atlanta, GA, USA, during 20-22 March 1990. This symposium, under the title "International Symposium on Structural Integrity of Aging Airplanes. was organized jointly be the Georgia Institute of Technology (Center for Computational Mechanics) and the Transportation Systems Center (Cambridge, MA) of the U.S. Department of Transportation. Industrial and academic experts from several countries in North America, Europe and Asia, were invited to discuss their experiences and proposed solutions. This monograph contains the original papers that represent the expanded and edited versions of the talks presented at this symposium. This book aims to bring the collective experience, from across the world, with problems related to the structural integrity of aging airplanes to the attention of the professional and research community at large - in the hope that it may stimulate further fruitful research on this important topic of global concern."

Many mechanical systems are actively controlled in order to improve their dynamic performance. Examples are elastic satellites, active vehicle suspension systems, robots, magnetic bearings, automatic machine tools. Problems that are typical for mechanical systems arise in the following areas: - Modeling the mechanical system in such a way that the model is suitable for control design - Designing multivariable controls to be robust with respect to parameter variations and uncertainties in system order of elastic structures - Fast real-time signal processing - Generating high dynamic control forces and providing the necessary control power - Reliability and safety concepts, taking into account the growing role of software within the system The objective of the Symposium has been to present methods that contribute to the solutions of such problems. Typical examples are demonstrating the state of the art It intends to evalua~ the limits of performance that can be achieved by controlling the dynamics, and it should point to gaps in present research and areas for future research. Mainly, it has brought together leading experts from quite different areas presenting their points of view. The International Union of Theoretical and Applied Mechanics (lUTAM) has initiated and sponsored, in cooperation with the International Federation of Automatic Control (IF AC), this Symposium on Dynamics of Controlled Mechanical Systems, held at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland, May 3D-June 3, 1988.

Gravity models describe, and hence help predict, spatial flows of commuters, air-travelers, migrants, commodities and even messages. They are one of the oldest and most widely used of all social science models. This book presents an up-to-date, consistent and unified approach to the theory, methods and application of the gravity model - which spans from the axiomatic foundations of such models all the way to practical hints for their use. "I have found no better general method for use in applied research dealing with spatial interaction... It is against this background that the present book by Sen and Smith is most welcomed." "Walter Isard"

The present book contains the papers that have been presented at the IUTAM-Symposium on Atmospheric Dispersion of Heavy Gases and Small Particles, which was held from August 29th to September 2nd 1983 in Scheveningen in The Netherlands. Attendees from many countries were present; 4 review lectures and about 25 research papers were presented. The realization of the symposium was made possible by the support of Delft University of Technology Koninklijke/Shell-Laboratory Amsterdam Prins Maurits Laboratory/Institute for Chemical and Technological Research Royal Netherlands Meteorological Institute. The symposium organization was carried out by the local organi- zing committee consisting of F.G.J. Absil - Delft University of Technology G.W. Colenbrander - Koninklijke/Shell-Laboratory Amsterdam G. Ooms - Delft University of Technology G. Opschoor - Prins Maurits Laboratory/Institute for Chemical and Technological Research H. Tennekes - Royal Netherlands Meteorological Institute A.P. van Ulden - Royal Netherlands Meteorological Institute. The work of the organizing committee was supported in many re- spects by the sientific committee, which consisted of H. Fiedler - Technische Hochschule Karlsruhe, Fed. Rep. of Germany F.N. Frenkiel - Naval Ship Research and Development Center, Bethesda, Maryland, U.S.A. J.C.R. Hunt - University of Cambridge, England J. Kondo - National Institute for Environmetal Studies, Japan J.L. Lumley - Cornell University, Ithaca, New York, U.S.A.

This handbook offers a comprehensive overview of Camera Monitor Systems (CMS), ranging from the ISO 16505-based development aspects to practical realization concepts. It offers readers a wide-ranging discussion of the science and technology of CMS as well as the human-interface factors of such systems. In addition, it serves as a single reference source with contributions from leading international CMS professionals and academic researchers.In combination with the latest version of UN Regulation No. 46, the normative framework of ISO 16505 permits CMS to replace mandatory rearview mirrors in series production vehicles. The handbook includes scientific and technical background information to further readers' understanding of both of these regulatory and normative texts.It is a key reference in the field of automotive CMS for system designers, members of standardization and regulation committees, engineers, students and researchers.

Master the knowledge and skills needed to diagnose and service suspension and steering systems for today's cars, SUVs, light duty trucks and now, hybrids, with the latest edition of this highly successful Classroom/Shop Manual package! With the same carefully constructed balance of theory and practice that made previous editions so valuable, the 5th Edition of TODAY'S TECHNICIAN: AUTOMOTIVE SUSPENSION AND STEERING, International Edition takes the content to the next level, from coverage of the latest mandatory tire pressure monitoring systems to the newest electronically-controlled suspension systems. And the highly updated, state-of-the-art information doesn't end there; the book also features new information on the most current front and rear suspension designs, recent developments in steering columns and air bag systems, and the latest electronic power steering gears. Reinforcing its practical, user-friendly approach are strategically placed cautions and warnings that emphasize safe working procedures and case studies that link theory to the real-life practices of today's professional, ASE-certified technicians, making this a must-have for aspiring and new automotive technicians alike!

At the suggestion of the USSR National Committee of Theo retical and Applied Mechanios the International Union of Theo retical and Applied Meohanics made a deoision to organize the Second IUTAM Symposium on Laminar-Turbulent Transition in No vosibirsk. Professor Yanenko was entrusted to be the chairman of the scientific committee. It was proposed that about 100 scientists would participate in the Symposium and that 60 lectures and invited lectures would be delivered; as for the theme of the Symposium, it was devoted to experimental and theoretical stu dies of laminar-turbulent transition in fluids and gases, i.e. the physical problems of transition and mathematical modeling in shear flows. It was planned to lay a special emphasis on fundamental mechanisms of the transition process. The scienti fio committee approved of the scope of the Symposium having considered the changes in the directions of the stUdies which took place since the First Symposium. For example, there was singled out the problem of transformation of external distur bances into eigenoscillations of shear flows, i.e. the recep tivity problem which was only slightly touched upon at the First Symposium. A new section appeared devoted to the inter relation of the flow separation phenomenon and its stability. It was planned to focus the attention on the secondary instability at transition to turbulence at the non-linear stage of the flow breakdown as well as on the loss of stability and the disturbances development in 3-D flows."

The book is based on an international workshop on High Precision Navigation. The reader will find a wealth of information on - satellite navigation systems and their geodetic applications, especially using GPS - laser and radar techniques - image processing and image sequence analysis - autonomous vehicle guidance systems - inertial navigation systems - integration of different sensor systems.

Software Diversity is one of the fault-tolerance means to achieve dependable systems. In this volume, some experimental systems as well as real-life applications of software diversity are presented. The history, the current state-of-the-art and future perspectives are given. Although this technique is used quite successfully in industrial applications, further research is necessary to solve some open questions. We hope to report on new results and applications in another volume of this series within some years. Acknowledgements The idea of the workshop was put forward by the chairpersons of IFIP WG lOA, J. -c. Laprie, J. F. Meyer and Y. Tohma, in January 1986, and the edi tor of this volume was asked to organize the workshop. This volume was edited with the assistance of the editors of the series, A. AviZienis, H. Kopetz and J. -C. Laprie, who also had the function of reviewers. Karlsruhe, October 1987 U. Voges, Editor Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Introduction U. Voges 2. Railway Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ERICSSON Safety System for Railway Control . . . . . . . . . . . . . . . . . . 11 G. Hagelin 3. Nuclear Applications . . . . . . . . . . . . . . . . . . . . . . 23 Use of Diversity in Experimental Reactor Safety Systems . 29 U. Voges The PODS Diversity Experiment . 51 P. G. Bishop 4. Flight Applications . . . . . . . . . . . . . . . . . . . . . . . . . 85 AIRBUS and ATR System Architecture and Specification. . 95 P. Traverse 5. University Research . . . . . . . . . . . . . . . . . . . 105 Tolerating Software Design Faults in a Command and Control System . . . . . . . . . . . . . . . . . . . . . . 109 T. Anderson, P. A. Barrett, D. N. Halliwell, M. R. Moulding DEDIX 87 - A Supervisory System for Design Diversity Experiments at UCLA . . . . . . . . . . . . . . . . . ."

Investigation of vortex wakes behind various aircraft, especially behind wide bodied and heavy cargo ones, is of both scientific and practical in terest. The vortex wakes shed from the wing's trailing edge are long lived and attenuate only atdistances of10-12kmbehindthe wake generating aircraft. The encounter of other aircraft with the vortex wake of a heavy aircraft is open to catastrophic hazards. For example, air refueling is adangerous operationpartly due to thepossibility of the receiver aircraft's encountering the trailing wake of the tanker aircraft. It is very important to know the behavior of vortex wakes of aircraft during theirtakeoff andlanding operations whenthe wakes canpropagate over the airport's ground surface and be a serious hazard to other depart ing or arriving aircraft. This knowledge can help in enhancing safety of aircraft's movements in the terminal areas of congested airports where the threat of vortex encounters limits passenger throughput. Theoreticalinvestigations of aircraft vortex wakes arebeingintensively performedinthe major aviationnations.Usedforthispurpose are various methods for mathematical modeling of turbulent flows: direct numerical simulation based on the Navier-Stokes equations, large eddy simulation using the Navier-Stokes equations in combination with subrigid scale modeling, simulation based on the Reynolds equations closed with a differential turbulence model. These approaches are widely used in works of Russian and other countries' scientists. It should be emphasized that the experiments in wind tunnels and studies of natural vortex wakes behind heavy and light aircraft in flight experiments are equally important.

This is the second part of the translation of the original German text Meerestechnische Konstruktionen which was published by Springer-Verlag in 1988. The translated material is a reviewed and updated version of the German text. Wheras the first volume concentrates on general and external factors, this one focuses on factors affecting the design and analysis of offshore structures themselves. In an effort to address a wide audience the topic is presented in a general context. Therefore it introduces students and practising engineers to the field of marine technology and, at the same time, serves as a reference book for experts. Finally it gives specialists in related fields an idea of where their work on individual problems of offshore structures stands in relation to the field as a whole. Offshore Structures, Vol. 2 is based on the authors' lectures and design practice in offshore structures and their components. It assists the reader in developing practical solutions by introducing a large number of examples and reference is made to further specialised literature.

This volume contains eighteen selected papers presented at the Second International Conference on Stochastic Structural Dynamics, which are related to new practical applications in the field. This and a companion volume, related to new theoretical developments, constitute the proceedings of the conference, and reflect the state of the art of the rapidly developing subject. The conference was held in Boca Raton, Florida during May 9-11, 1990 hosted by the Center for Applied Stochastic Research of Florida Atlantic University. A total of 20 technical sessions were organized, and attended by eighty participants from 12 countries. Special emphases of the conference were placed on two areas: applications to earthquake engineering and stochastic stability of nonlinear systems. Two sessions were dedicated to the memory of late Professor Frank Kozin, one of the founders and most active contributors to the stochastic stability theory. We are indebted to the National Center for Earthquake Engineering Research (NCEER) for financial support. Most credit belongs to each of the authors whose contributions were the very basis for the undoubted success of the conference. We are grateful to the reviewers who carefully refereed the contributions for these two volumes. Our special thanks are due to Mrs. Christine Mikulski, who carried out all the necessary secretarial tasks associated with the conference with dedication.

Separated flows and jets are closely linked in a variety of applications. They are of great importance in various fields of fluid mechanics including vehicle efficiency, technical branches concerned with gas/liquid flows, atmospheric effects on various constructions, etc. Knowledge of the physics of separated flows and jets and the development of reliable control techniques are prerequisite for future progress in the field. These aspects were in focus during the IUTAM-Symposium which was held in Novosibirsk, 9-13 July, 1990. This volume contains a selection of papers presenting recent results of theoretical and numerical studies as well as experimental work on separated flows and jets. The topics include sub- and supersonic, laminar and turbulent separation as well as organized structures in separated flows and jets. The reader will find here the state of the art and major trends for research in this field of aero-hydrodynamics.

The problems of urban traffic in the industrially developed countries have been at the top of the priority list for a long time. While making a critical contribution to the economic well being of those countries, transportation systems in general and highway traffic in particular, also have detrimental effects which are evident in excessive congestion, high rates of accidents and severe pollution problems. Scientists from different disciplines have played an important role in the development and refinement of the tools needed for the planning, analysis, and control of urban traffic networks. In the past several years, there were particularly rapid advances in two areas that affect urban traffic: 1. Modeling of traffic flows in urban networks and the prediction of the resulting equilibrium conditions; 2. Technology for communication with the driver and the ability to guide him, by providing him with useful, relevant and updated information, to his desired destination.

Prices and quantities of both stock and flow variables in an economic system are decisively influenced by their spatial coordinates. Any equilibrium state also mirrors the underlying spatial structure and a tatonnement process also incorporates the spatial ramifications of consumer and producer behaviour. The recognition ofthe spatial element in the formation of a general equilibrium in a complex space-economy already dates back to early work of LOsch, Isard and Samuelson, but it reached a stage of maturity thanks to the new inroads made by T. Takayama. This book is devoted to spatial economic equilibrium (SPE) analysis and is meant to pay homage to the founding father of modern spatial economic thinking, Professor Takayama. This book witnesses his great talents in clear and rigorous economic thinking regarding an area where for decades many economists have been groping in the dark. Everybody who wants to study the phenomenon of spatial economic equilibrium will necessarily come across Takayama's work, but this necessity is at the same time a great pleasure. Studying his work means a personal scientific enrichment in a field which is still not completely explored. The present volume brings together recent contributions to spatial equilibrium analysis, written by friends and colleagues of Takayama. The structure of the book is based on four main uses of spatial equilibrium models: (i) the imbedding of spatial flows in the economic environment, related to e.g.

IUTAM-IAHR Symposium on Ice-Structure Interaction Professor Bez Tabarrok, Chairman of the Canadian National Committee (CNC) of the International Union of Theoretical and Applied Mechanics (IUTAM) invited Professor Derek Muggeridge to organize a symposium on ice structure interaction. Dr. Muggeridge readily agreed and prepared a proposal that was endorsed by the CNC and presented to the General Assembly Meeting of IUTAM for their consideration. This Assembly gave its approval and provided the local organizing committee with the names of individuals who were willing to serve on the Scientific Committee. Dr. Muggeridge became chairman of this committee and Dr. Ian Jordaan became co-chairman of this committee as well as chairman of the local organizing committee. The symposium followed the very successful previous meeting, chaired by Professor P. Tryde in Copenhagen, by ten years. Both symposia uti lized Springer-Verlag to publish their proceedings. The Faculty of En gineering and Applied Science at Memorial University of Newfoundland were particul{lXly pleased to host this prestigious symposium as it marked the twentieth anniversary of its Ocean Engineering Research Centre."

Rail is potentially a very efficient form of transport, but must be convenient, reliable and cost-effective to compete with road and air transport. Optimal control can be used to find energy-efficient driving strategies for trains. This book describes the train control problem and shows how a solution was found at the University of South Australia. This research was used to develop the Metromiser system, which provides energy-efficient driving advice on suburban trains. Since then, this work has been modified to find practical driving strategies for long-haul trains. The authors describe the history of the problem, reviewing the basic mathematical analysis and relevant techniques of constrained optimisation. They outline the modelling and solution of the problem and finally explain how the fuel consumption can be minimised for a journey, showing the effect of speed limits and track gradients on the optimal driving strategy.