The generic denomination of ‘Memetic Algorithms’ (MAs) is used to encompass a broad class of metaheuristics (i.e. general purpose methods aimed to guide an underlying heuristic). The method is based on a population of agents and proved to be of practical success in a variety of problem domains and in particular for the approximate solution of NP Optimization problems. Unlike traditional Evolutionary Computation (EC) methods, MAs are intrinsically concerned with exploiting all available knowledge about the problem under study. The incorporation of problem domain knowledge is not an optional mechanism, but a fundamental feature that characterizes MAs. This functioning philosophy is perfectly illustrated by the term “memetic”. Coined by R. Dawkins [52], the word ‘meme’ denotes an analogous to the gene in the context of cultural evolution [154]. In Dawkins’ words:

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A Gentle Introduction to Memetic Algorithms

An elastic double-shell model is presented for infinitesimal buckling of a double-walled carbon nanotube embedded in an elastic matrix under axial compression. The analysis is based on a Winkler model for the surrounding elastic medium and a simplified model for the van der Waals interaction between the inner and outer nanotubes. An explicit formula is derived for the critical axial strain, which indicates the effects of the surrounding elastic matrix combined with the intertube van der Waals forces. In particular, the present model predicts that the critical axial strain of the embedded double-walled nanotube is lower than that of an embedded single-walled nanotube under otherwise identical conditions. This implies that inserting an inner tube lowers the critical axial strain of an embedded single-walled carbon nanotube, although the total critical compressive force could be increased due to the increase in the cross-sectional area of the nanotube. The reduced critical axial strain is attributed to the intertube slips between the inner and outer tubes. This result indicates that embedded multi-walled carbon nanotubes could be even more susceptible to infinitesimal axial buckling than embedded single-walled carbon nanotubes.

Axially compressed buckling of a doublewalled carbon nanotube embedded in an elastic medium

Preface. Part 1: Introduction. 1. Introduction to the Biomechanics of Human Movement. 2. Fundamentals of Biomechanics and Qualitative Analysis. Part 2: Biological/Structural Bases. 3. Anatomical Description and its Limitations. 4. Mechanics of the Musculoskeletal System. Part 3: Mechanical Bases. 5. Linear and Angular Kinetics. 6. Linear Kinetics. 7. Angular Kinetics. 8. Fluid Mechanics. Part 4: Applications of Biomechanics in Qualitative Analysis. 9. Applying Biomechanics in Physical Education. 10. Applying Biomechanics in Coaching. 11. Applying Biomechanics in Strength and Conditioning. 12. Applying Biomechanics in Sports Medicine and Rehabilitation. References. Appendix A: Glossary. Appendix B: Conversion Factors. Appendix C: Suggested Answers to Selected Review Questions. Appendix D: Right Angle Trigonometry Review. Appendix E: Qualitative Analysis in Biomechanical Principles. Index. Lab Activities. About the Author. Index.

Fundamentals of Biomechanics

Research on expertise, talent identification and development has tended to be mono-disciplinary, typically adopting genocentric or environmentalist positions, with an overriding focus on operational issues. In this paper, the validity of dualist positions on sport expertise is evaluated. It is argued that, to advance understanding of expertise and talent development, a shift towards a multidisciplinary and integrative science focus is necessary, along with the development of a comprehensive multidisciplinary theoretical rationale. Here we elucidate dynamical systems theory as a multidisciplinary theoretical rationale for capturing how multiple interacting constraints can shape the development of expert performers. This approach suggests that talent development programmes should eschew the notion of common optimal performance models, emphasize the individual nature of pathways to expertise, and identify the range of interacting constraints that impinge on performance potential of individual athletes, rather than evaluating current performance on physical tests referenced to group norms.

Expert performance in sport and the dynamics of talent development

The major racket sports include badminton, squash, table tennis and tennis. The growth of sports science and the commercialization of racket sports in recent years have focused attention on improved performance and this has led to a more detailed study and understanding of all aspects of racket sports. The aim here, therefore, is to review recent developments of the application of science to racket sports. The scientific disciplines of sports physiology and nutrition, notational analysis, sports biomechanics, sports medicine, sports engineering, sports psychology and motor skills are briefly considered in turn. It is evident from these reviews that a great deal of scientific endeavour has been applied to racket sports, but this is variable across both the racket sports and the scientific disciplines. A scientific approach has helped to: implement training programmes to improve players’ fitness; guide players in nutritional and psychological preparation for play; inform players of the strategy and...

Science and the major racket sports: a review

The book provides an in-depth coverage of the state-of-the-art in sports technology and the latest contemporary developments in this area from the perspective of both industrial practice and academic research. It includes a wide range of sport disciplines and technologies, encompassed by topics such as design innovation and product development, mechanics, biomechanics, aerodynamics, materials and advanced analysis techniques.

The Engineering of Sport

In elite cycling the resistive force is dominated by aerodynamics. Be it on the roads or in the velodrome, the sport has many examples where aerodynamics has won and lost races. Since the invention of the bicycle, engineers have strived to improve performance, often by reducing aerodynamic drag. Over the last 50 years a number of authors have presented their efforts in journals, books and magazines. This review summarises the publications that show the continued development in the aerodynamics of cycling. The review concludes by examining the shortcomings of the current understanding and making suggestions for future research and development.

The understanding and development of cycling aerodynamics

The purpose of this study is to assess the fundamental characteristics which cause a football to spin in a curve ball kick. The ball impact process was analysed initially with a high speed video camera running at 4500 frames per second to obtain the basic data for a computer simulation model. This simulation model showed suitable agreement although it slightly deteriorated during the latter half of impact. It was noted that rotation of the ball occurs, even if the kinetic coefficient of friction is nearly equal to 0 because of local deformation of the ball during impact around the foot allowing forces to be transmitted to the ball around its axis. The spin of the ball was found to increase with the offset distance between the foot and the axis of the ball and as the kinetic coefficient of friction was increased. The offset distance between the foot and the axis of the ball affects the spin more than the coefficient of friction. Varying the coefficient of friction from 0.0 to 1.0 produces an increase in spin of 13 rad s )1 at most. It was suggested that the most suitable offset distance, which makes the largest ball rotation was around 100 mm. A trade-off was found between the ball speed and spin, for different offset distances.

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The curve kick of a football I: impact with the foot

The purpose of this study is to assess the fundamental characteristics that cause a football to spin in a curve ball kick due to impact conditions, and then to examine how the change in spin affects the flight of the ball. Two experimental trials were carried out to examine the aerodynamic properties of footballs during flight. In the first trial, a football was projected with no spin at varying launch velocities and the trajectory of each flight measured and analysed. A drag coefficient was calculated for each test, based on a trajectory model. The second trial involved a football being fired with the same launch velocity, but varying spin conditions (spin axis horizontal in all cases). Again, the trajectory of each flight was measured and drag and lift coefficients were calculated. This information was used to simulate three typical game situations and the effects of foot impact offset distance and weather conditions were examined.

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The curve kick of a football II: flight through the air

Analysis of results from the four major tennis tournaments shows that the percentage of tie breaks in the men's game has been increasing over the last 30 years. It is hypothesised that this is due to the increasing speed of the serve in the game. There was found to be a significant difference in tie breaks between slower clay surfaces and faster grass surfaces. The women's game, on the other hand, showed no increase in tie-breaks and no difference in the number of tie-breaks between court surfaces. 

A larger tennis ball was assessed to see its effect in slowing the game down. Standard and 6% larger pressurised tennis balls were used in experiments to study impacts with a fixed and a freely suspended tennis racket. The coefficient of restitution of the larger ball was found to be larger in the fixed racket tests and analysis of a serve showed that the larger ball would be served marginally faster than a standard sized ball. 

Drag forces on tennis balls in flight were analysed by mounting tennis balls in a wind tunnel at wind speeds up to 66.6 ms−1 (150 mph). It was found that different brands of standard size tennis ball and a larger tennis ball had a drag coefficient of approximately 0.55. Raising or reducing the nap of the ball changed the drag coefficient by about 10%. Impact experiments of tennis balls on court surfaces showed that the larger and standard tennis balls rebounded at approximately the same speed at 70% of impact speed on acrylic and 64% of impact speed on clay. Both sizes of ball bounced steeper off clay than on acrylic. It appeared that the larger ball rebounded steeper than the standard ball, although evidence for this was clouded by considerable scatter in the data. 

A computer trajectory program was used to analyse simulated first and second serves at nominally 53.3 ms−1 (120 mph) and 40 ms−1 (90 mph). It was found that a larger ball would increase travel time to the baseline by approximately 10 ms for a first serve and up to 16 ms for a second serve. This increase was found to be just less than half that between acrylic and clay for the same ball. Travel time is increased further if the ball is increased in diameter. It was concluded therefore that the introduction of a larger ball could slow the game of tennis for all strokes and increase the time available for the receiver to return the ball.

Steve Haake

Papers

The Engineering of Sport

The understanding and development of cycling aerodynamics

The curve kick of a football I: impact with the foot

The curve kick of a football II: flight through the air

Engineering tennis – slowing the game down