bluuebunny/crossref_metadata_2025 huggingface dataset:
Derivative Instruments in the EU Emissions Trading Scheme — An Early Market Perspective
Authors: Uhrig-Homburg Marliese , Wagner Michael
Published: September 2008

The advent of the EU Emissions Trading Scheme (EU ETS) introduced CO2 emission allowances as a new tradable asset. Market participants now face the question how to manage the risks associated with these emission certificates. In this paper we discuss the market environment in the EU ETS and present the results and implications of an expert survey, which gives a perspective on the development of derivative markets in the EU ETS. Although the EU ETS exhibits some differences, in that it is not only driven by fundamentals but also strongly by regulatory and political factors, we find that the EU ETS develops in a similar fashion to other financial and commodity markets. Moreover, the expert survey gives a clear indication that there are realistic chances for the long-term success of derivatives, not only for futures and forwards but also – to a lesser extent – for more asymmetric, option-like instruments.
Reconsideration of Climate Change from the Viewpoints of Greenhouse Gas Types and Time Scale
Authors: Kikuchi Ryunosuke
Published: September 2008

When the Earth's surface warms and emits long-wave infrared (IR) radiation, IR active gases (e.g. CO2, CH4, etc.) effectively absorb it; CO2 is therefore one of the major challenges facing the climate research community. However, in Europe recent radiation measurement over about a decade shows that rapid temperature increase is mainly (∼65%) caused by water vapor. The following points are established through the main discussion: (i) there are a number of factors causing climate change (e.g. astronomical factors), that is, CO2 is just one of various climate drivers; (ii) the coupling complexity of CO2 with climate is enhanced by the time-scale extension; and (iii) this complexity involves various climate drivers with different cycles and magnitudes. The Earth's atmosphere has evolved over the last 4.5 billion years and still continues to evolve; thus, climate variability must be inevitable and complex. Future climate change may be drawn from the newly emerging discipline of complexity science.
Multi-Level Governance Conditions for Implementing Multilateral Environmental Agreements: The Case of CDM Forestry Readiness in Cameroon
Authors: Minang Peter A , McCall Michael K.
Published: September 2008

Multilateral Environmental Agreements including the Clean Development Mechanism represent complex multi-level governance systems that often face serious implementation challenges especially in developing countries. This paper presents a framework for assessing the capacity or readiness for the implementation of Multilateral Environmental Agreements (MEAs), within the context of CDM forestry of the Kyoto Protocol of the UNFCCC in the first instance, and specifically analyses issues of multi-level governance relevant for successful implementation in Cameroon. The framework highlights a set of key cross-scale enabling conditions for MEA implementation including regulatory compatibility, institutional synergy, complementary and coordinated capacities, information and data availability and the presence of governance mechanisms. The research has identified the need for targeted policy actions for enhancing regulatory compatibility and institutional synergy between levels of the formal system – i.e. global, national, sectoral, sub-national and local levels. However, we have also highlighted the problems of, not just the conflicts between forms and functions of governance between the formal national set ups and community ‘traditional’ institutions, but even the lack of common understanding between them. Overcoming these gaps will require considerably more open-minded and reciprocal communication, and respect for differing perceptions in the implementation of MEAs. The relevance of a framework for assessing multi-level governance in a post 2012 Reduced Emissions from Deforestation and Degradation mechanism is also underlined.
Separation of Resonant and Non-Resonant Components—Part II: Surface Velocity
Authors: Mahn Jeffrey , Stevenson D. Cliff
Published: September 2008

In this second paper, the separation of the resonant and non-resonant components of the mean square velocity of lightweight building elements is investigated for use with EN12354. Two methods for separating the components are presented. The first involves measuring the mean square velocity of a series of panels, each with a different amount of damping. A modified least squares approach is then used. The second method uses the velocity level difference between building elements measured according to EN10848 and the measurement of the mean square velocity of the elements due to excitation by an airborne noise source. This offers advantages since it adds a few additional steps to the measurements for EN10848. However this method was not successful over the entire frequency range when applied to the elements used in this study.
Acoustical Evolution of the Roman Theatre of Ostia
Authors: Gugliermetti F. , Bisegna F. , Monaco A.
Published: September 2008

Archaeologists are faced with the problem of historical reconstruction of ancient theatres that are in different states of conservation and, over the centuries, have suffered often dramatic changes. Acoustics can play an important role in guiding the choice of the most accurate reconstruction from different possible alternatives. Computer-aided simulations can provide a well-established tool for this task. The Roman theatre of Ostia Antica has been the subject of many studies of its architecture over the centuries, from the original construction of Agrippa (beginning the first century B.C.), to the drastic reconstruction of 1927. This paper presents different virtual reconstructions of the theatre of ancient Ostia. It reports on in-situ measurements, made in presence of a provisional stage, which have been compared with other related studies on ancient theatres of the Roman era. Auralization techniques are employed to investigate performance in different eras. An acoustic history of the theatre is given, from Roman times to the present day.
Effect of Geometrical Nonlinearity on the SAVIS Device
Authors: Yan An-Zhi , Teng Jun , Lu Zhi-Xiong , Wang Qin Ting
Published: September 2008

The excessive stroke of semi-active variable stiffness-tuned mass damper (SATMD) which causes large distortion is common in practice. The effects of the geometrical nonlinearity of the semi-active variable stiffness (SAVIS) device have been investigated and are described in this paper. An expression which includes the stiffness nonlinearity of the device is obtained. A cubic polynomial model of the equivalent stiffness is approximately obtained using the least squares interpolation method. First, the simplified coupled nonlinear equations with no forcing and no damping are approximately solved using the multiple scale method. The results show that the vibration frequency of the primary system can be modulated by the nonlinearity of the SAVIS device, and the 1:1, 1:3 and 3:1 internal resonance may occur in some conditions. Second, using the Runge-Kutta method, the iteration results are obtained under a full period sine-wave pulse and under the El Centro seismic record. Standard deviation (STD) responses and peak responses of the system are calculated for different damping ratios and different local frequency ratios. The power spectra distribution (PSD) of the response of a nonlinear system shows that the local frequency will be shifted, and the effect on the vibration control of the main structure is much better for a nonlinear case than for a linear case as the frequency ratio is less than one under both the sine-wave pulse and the El Centro seismic excitation.
Seismic Performance of a Special Type of Single-Story Eccentrically Braced Steel Frame
Authors: Dicleli Murat , Mehta Anshu
Published: September 2008

This research is aimed at studying the seismic response of a single story non-buckling eccentrically braced steel frame (NBF) in relation to conventional moment resisting frame (MRF) and concentrically braced frame (CBF). The NBF is intended to combine the advantages of MRF and CBF and eliminate most of the disadvantages pertinent to these frames. Nonlinear static pushover and time history analyses are conducted to assess the performance of the NBF compared to the performance of MRF and CBF. The analyses results have revealed that the NBF has a more stable lateral force-deformation behavior compared to CBF. The energy dissipation capacity of the NBF is comparable to that of the MRF. The maximum drift of the NBF at small to medium intensity ground motions is comparable to that of the CBF and smaller than that of the MRF. At high intensity ground motions, the maximum drift of the NBF is smaller than those of both CBF and MRF. Furthermore the NBF is found to experience less damage to its essential structural components compared to other frames.
A Simplified Method for the Buckling of Outrigger-Shear Wall Braced Structures
Authors: Tong Geng-Shu , Weng Yun
Published: September 2008

This paper presents the analysis of the buckling of single-outrigger-shear-wall braced structures in which the shear-deformable outrigger is located at an arbitrary height. The contributions of component rigidities and the location of the outrigger to the overall stiffness of outrigger-shear-wall braced structures have been identified. A continuous model, where the exterior frames attached to the outrigger are modeled as shear-deformable-only and the action of the outrigger on the shear wall is replaced by a rotational restraint at the outrigger level, was used to analyze the buckling of single-outrigger-shear-wall braced structures. Analytical and approximate solutions are presented and compared with each other, and verification analyses were carried out using FEM. It is found that the outrigger-shear-wall braced structure may be considered as a type of dual structural system, although some of the exterior frame columns contribute to the function of the outrigger-shear-wall system. The total critical load for the outrigger-shear-wall braced structure is the sum of the critical loads for the frames and for the outrigger-shear-wall systems when they are each considered to function as independent structures. Although this paper is not intended to replace overall buckling analysis of this type of structure, the conclusion of this paper is helpful for understanding the behaviour of real outrigger-shear-wall braced structures against buckling.
Occurrence Probability of Wind-Rain-Induced Stay Cable Vibration
Authors: Xu Y. L. , Chen J. , Ng C. L. , Zhou H. J.
Published: September 2008

Wind-rain-induced vibration of stay cables in cable-stayed bridges has been increasingly concerned by engineering professions. This paper presents a framework for estimating occurrence probability of wind-rain-induced stay cable vibration to facilitate the engineering decision on the implementation of anti-vibration system. The proposed framework is founded on the statistical analysis of wind speed, wind direction and rainfall intensity and the theoretical analysis of occurrence range of wind-rain-induced stay cable vibration. The joint probability density function of wind speed and wind direction, and the probability density function of rainfall intensity are first obtained for the site of a bridge through the statistical analysis. The occurrence range of wind speed and wind direction for wind-rain-induced vibration of a stay cable greater than a vibration amplitude threshold value is then found based on a theoretical model recently developed. The occurrence probability and risk of wind-rain-induced stay cable vibration are finally calculated according to the probability theory. The practical use of the proposed framework is demonstrated in this paper by taking a typical stay cable in a real cable-stayed bridge as a case study.
Experiment and Analysis on the Mechanical Behaviour of PC Simply-Supported Slabs Subjected to Fire
Authors: Zheng Wenzhong , Hou Xiaomeng
Published: September 2008

Experiments on the fire resistance of 9 unbonded and 1 bonded prestressed concrete (PC) simply-supported slabs are completed. Calculation formula of the stress in the unbonded prestressing steel wires in PC simply-supported slabs subjected to fire is obtained based on the experimental results. Dividing the section of the slab into strips along its depth according to the distribution of temperature field, on the basis of invariable width of the slab in the surface exposed to fire, the transformed section of the slab subjected to fire can be obtained by multiplying the width of each strip by the elasticity modulus ratio of the strip concerned and the extreme strip in the surface exposed to fire. The stress in concrete and curvature in the researched section caused by load can be obtained based on equilibrium equations of force and moment on transformed section. Then, the methods for calculating concrete thermal strain, transient strain and creep at elevated temperature were introduced, and total strain of a point in the concerned section and total curvature caused by load and temperature can be calculated considering time-dependent effect. After the total curvature of the mid-span section was calculated, the actual stiffness of the critical section in the mid-span can be determined, moreover, the mid-span deflection of the PC slab can be calculated by the virtual displacement principle. The practical calculation formulas for the mid-span deflection of PC simply-supported slabs subjected to fire is presented considering the influences of the deflection of slabs at the ambient temperature, ratio of concrete cover to depth of slabs, load level, combined reinforcement index and span.
Stress Characteristics and Fatigue Crack Behaviour of the Longitudinal Rib-To-Cross Beam Joints in an Orthotropic Steel Deck
Authors: Choi Jun-Hyeok , Kim Do-Hwan
Published: September 2008

The welded joints between longitudinal rib and crossbeam of an orthotropic steel bridge deck are potentially critical to fatigue failure due to stress concentration at the end of the weld toe, caused by in-plane and out-of-plane deformations due to negative bending moments produced by live loads on the deck. The objective of this study is to evaluate the stress characteristics and fatigue crack behaviour of the longitudinal rib-to-crossbeam joints in an orthotropic steel bridge deck and to investigate the effectiveness of crack repair using a stop-hole. Static and fatigue test on full scale specimens were performed to observe the fatigue strength and crack propagation at the longitudinal rib-to-crossbeam joints. The measured stress distributions were compared with the F.E. analysis results. The test results show that fatigue cracks are initiated at the weld toe of the longitudinal rib-to-crossbeam joint with an inclined angle and rib-to-deckplate joint. Fatigue crack growth of the joint was analyzed by the mixed-mode analysis using the strain energy density factor. The stop-hole method was applied to delay fatigue crack growth of the longitudinal rib-to-crossbeam joint.
Design of Cold-Formed Steel Purlins Attached to Roof Sheeting Based on Eurocode 3: Effect of Gravity Load
Authors: Katnam K. B. , Van Impe R. , Lagae G. , De Strycker M.
Published: September 2008

In the design of cold-formed steel purlins based on Eurocode 3, the lateral bending moment in the free flange of the purlin, when in tension, is assumed to be zero due to flange curling and second order effects. To investigate the validity of this design assumption, non-linear analytical and finite element models for analyzing how the gravity load affects the maximum mid-span stresses in cold-formed steel purlins attached to the roof sheeting are presented in this paper. The second-order effect of tensile stresses induced by the gravity load in the free flange of purlins is investigated by emphasizing on Z and C sections. The results obtained from the two models are compared with Eurocode 3, and they are included in this article. It is observed that for shorter purlin span lengths the design assumption underestimates the maximum mid-span stresses.
Optimal Bounded Control of Hysteretic Systems under External and Parametrical Random Excitations
Authors: Wang Y. , Ying Z. G. , Zhu W. Q.
Published: September 2008

A method for designing optimal bounded control of nonlinear hysteretic systems under externally and parametrically random excitations is presented and illustrated with a numerical example on hysteretic column. The hysteretic system subjected to random excitations is firstly replaced by an equivalent nonlinear non-hysteretic stochastic system. Then, the Itô stochastic differential equation for the total energy of the system as a controlled diffusion process is derived by using the stochastic averaging method of energy envelope. For the semi-infinite time interval ergodic control, the dynamic programming equation is established based on the stochastic dynamical programming principle, and the optimal bounded control law is obtained from this equation under the control constraint. The responses of uncontrolled and controlled hysteretic systems are predicted and used for evaluating control efficacy. The robustness of the optimal bounded control for the hysteretic system with uncertain parameters is further analyzed. Numerical results show that the proposed control method has high efficacy and good robustness.
Pounding Reduction of Highway Bridges with Pounding Effect by Using Magnetorheological Dampers under Earthquake Excitations
Authors: Guo A.X. , Li H.
Published: September 2008

Seismic pounding between the adjacent segments of the multi-span concrete highway bridges can result significant structural damage. The aim of this paper is to investigate the possibility of using magnetorheological (MR) dampers to reduce the collision between the adjacent segments of the highway bridges in severe seismic events. The analysis of this study is focused on the highway bridges with base-isolated rubber bearings. The nonlinear equation of dynamic equilibrium of the structures is first established considering the pounding effect of the bridges under earthquake excitations. As a basis for the design of the semi-active control system, an active control system is developed by employing the instantaneous optimal control algorithm to determine the active control forces of the actuators. The MR dampers of the semi-active control system are designed to trace the instantaneous optimal control forces for manipulating the dampers. The control algorithm is then modified to incorporate the time delay effect of the control system based on predictive control algorithm. A highway bridge with five segments is analyzed by using the proposed method. The results show that the semi-active control system can effectively reduce the structural pounding of the highway bridges under earthquake excitations if the semi-active control system is appropriately designed.
Finite Element Model Updating for the Runyang Cable-Stayed Bridge Tower Using Ambient Vibration Test Results
Authors: Ding Youliang , Li Aiqun
Published: September 2008

The finite element (FE) model updating method aims to fit the parameters of a given initial analytical model in such a way that the model behavior corresponds as closely as possible to the measured behavior. However, the success of applications of the method depends on the analytical conceptualization of complex civil engineering structures, a well-designed and controlled modal test and an integration of analytical and experimental arts. This paper presents a sensitivity-analysis-based FE model updating procedure for FE model updating of Runyang Cable-stayed Bridge tower based on ambient vibration measurements. The updated model results correlate well with the experimental data in both the active frequency range and the passive frequency range. Extensive comparisons are made among the results obtained from different model updating cases. It is found that the appropriate initial FE model and determination of updating parameters are very important for the FE model updating of Runyang Cable-stayed Bridge tower.
Parametric Studies on Inter-Column Brace Forces
Authors: Zhang Yaochun , Zhao Jinyou , Zhang Wenyuan
Published: September 2008

In past studies on the design forces of inter-column braces, only the randomness of the initial imperfections of the columns was considered and the horizontal inter-column braces located at mid-height of columns were assumed to be effective only in compression. Actually, the initial imperfections of both the columns and the braces are random variables and the combination of the initial imperfections between them is also random. In this paper, the initial imperfections of the columns and the braces were randomly taken by Monte Carlo method, and a large number of the column-bracing systems with random combinations of the initial imperfections were modeled and analyzed by second-order analysis using finite element method. The binormal probability density function of bracing forces was found based on numerical calculations, parametric analyses and probability statistics. The results indicate that random combination of the initial imperfections between columns and braces leads to the randomness of horizontal inter-column brace forces in compression or in tension. The design forces of these braces have been obtained and a design formula has also been proposed. It is found that the design forces of these braces are smaller than those given in GB50017–2003, Eurocode 3 -1992 and AS4100–1998.
Source-Mechanism Identification by Nearfield-Farfield Pressure Correlations in Subsonic Jets
Authors: Jordan E. Laurendeau P. , Delville J. , Bonnet J.-P.
Published: September 2008

Simultaneous pressure measurements are performed in the near and farfield regions of a subsonic jet, and natural and fluidically controlled cases are studied. The measurements are used to examine: (1) the causal relationship between the coherent dynamic of the flow and the sound field it produces; and, (2) the localisation and directive character of a broadband high-frequency component of the sound field which is sometimes associated with the fine-scale turbulence. By varying the axial and radial positions of a nearfield microphone, correlations with 10 farfield microphones are used to study the source signatures in three regions: the near-nozzle region (nearfield microphone at x/D = 1), the mixing-layer region (nearfield microphone at x/D = 3), and the end of the potential core (nearfield microphone at x/D = 5). The correlations reveal a number of distinctive signatures in both baseline and controlled flows, and arguments are presented which relate these to the following kinds of source mechanism: (1) a wavy-wall mechanism associated with Kelvin-Helmholtz structures in the initial stages of the flow, and which comprises a distinctive tri-modal structure with marked directivity patterns in the upstream regions; (2) a more monochromatic wave-like mechanism at the end of the potential core; (3) a broadband high-frequency source whose directivity is a strong function of axial position, in contrast with the common assumption that this component radiates omnidirectionally; and, (4) a highly directive, localised source associated with vortex shedding from the blunt trailing edge of the nozzle. The comparison of results between the controlled and uncontrolled cases demonstrates the relative inefficiency of this kind of control in producing a fundamental change in the said source mechanisms.
Effect of Air Injection on the Far Field Pressure Radiated from a Jet at Subsonic Mach Numbers
Authors: Camussi Roberto , Guj Giulio , Tomassi Francesco , Sisto Renata
Published: September 2008

This paper deals with an experimental study of the acoustic field resulting from the interaction between the air injected from 6 microjets and the flow issuing from a round jet at low and high subsonic Mach numbers. The displacement and inclination of the microjet axes with respect to the main stream direction, as well as the ratio between the microjets and the main jet flow rates, are varied parametrically and the effect on the far field sound is analyzed. In the low Mach number cases no relevant influence upon the acoustic field is observed. This is probably an effect of the limited number of microjets activated. On the contrary, when the flow becomes highly compressible, a significant alteration of the far field acoustic pressure with respect to the baseline conditions is detected. The most relevant effect is observed when the microjet axes are placed in direction perpendicular to that of the main stream. In these cases the pressure energy is considerably reduced and a significant overall noise abatement, of the order of more than 2dB, is achieved.
Utilization of Turbulent Energy Transfer Rate Time-Scale in Aeroacoustics with Application to Heated Jets
Authors: Self Rod H. , Azarpeyvand Mahdi
Published: September 2008

This paper presents a study of the effects of the form of the time-scale used in aerodynamic noise prediction methodologies with application to the prediction of noise from hot jets. It was motivated by the need to improve the spectral shape of predictions obtained using Lighthill Acoustic Analogy based schemes such as the MGBK method in conjunction with a RANS CFD flow simulation. Acoustic Analogy formulations require knowledge of the unsteady characteristics of the turbulence whereas using a RANS calculation as the starting point provides only steady characteristics of the flow and it is then necessary to model the unsteady behaviour in some way. A critical issue is the proper definition of the acoustic time scale which empirical studies have shown to be frequency dependent. The authors discuss how this dependence arises from the underlying physics of the flow by considering a timescale based on the rate of energy transfer through the turbulent cascade. The technique is applied to noise prediction for both isothermal and heated jets using the MGBK method. It is shown that using the new definition of timescale results in good agreement with experimental measurements in both cases. It is suggested that such a definition will prove robust and find application in other areas of aeroacoustic noise prediction.
Constraint-Based Design in Participatory Housing Planning
Authors: Donath Dirk , Böhme Luis Felipe González
Published: September 2008

We introduce some novel ideas for a constraint-based design strategy to support participatory housing planning processes in Latin America. The following lines intend to open the discussion on the requirements and effect of the computer implementation of a constraint satisfaction approach to solve elementary design problems in architectural practice. The case study applies to the building massing design problem posed by the Chilean urban regulatory framework that addresses single-family affordable houses. Two different implementation criteria are being tested in an ongoing series of trials providing further considerations. One prototype uses MAXON's CINEMA4D XPRESSO ® visual scripting environment to set up a semi-automated design environment which allows users to edit one feature-based 3D model of massing alternative at a time. The other prototype uses ILOG's OPL STUDIO ® constraint programming environment to achieve fully automated search and 2D visualization of all possible solution alternatives to separate subdomains of the building massing design problem.
Spatial Augmented Reality for Architecture — Designing and Planning with and within Existing Buildings
Authors: Tonn Christian , Petzold Frank , Bimber Oliver , Grundhöfer Anselm , Donath Dirk
Published: September 2008

At present, more than half of all building activity in the German building sector is undertaken within existing built contexts. The development of a conceptual and technological basis for the digital support of design directly on site, within an existing building context is the focus of the research project “Spatial Augmented Reality for Architecture” (SAR). This paper describes the goals achieved in one aspect of the project: the sampling of colors and materials at a scale of 1:1 using Augmented Reality (AR) technologies. We present initial results from the project; the development of an ad-hoc visualization of interactive data on arbitrary surfaces in real-world indoor environments using a mobile hardware setup. With this, it was possible to project the color and material qualities of a design directly onto almost all surfaces within a geometrically corrected, existing building. Initially, a software prototype “Spatial Augmented Reality for Architecture-Colored Architecture” (SAR-CA) was developed and then assessed based on evaluation results from a user study.
CityZoom: A Visualization Tool for the Assessment of Planning Regulations
Authors: Turkienicz Benamy , Gonçalves Bárbara Bellaver , Grazziotin Pablo
Published: September 2008

A city modelled according to planning regulations usually presents a correlation between plots and building dimensions. To simulate the overall impact of building regulations over a large number of plots it is advantageous to use a computational tool to perform the task. Existing software can generate proxies of the would be reality, but do not accurately simulate the impact of alternative urban regulations. CityZoom is a Decision Support System for urban planning which not only provides CAD tools, but also allows users to evaluate and modify the city model according to different constraints such as solar radiation, luminance, terrain's pervious conditions, etc‥ By simulating specific urban regulations and addressing environmental comfort issues, CityZoom helps architects to simultaneously evaluate the different attributes of a particular design. Coupled with GIS tools, CityZoom allows users to perform multiple analyses over the existing database and use the resultant feedback to optimize proposed solutions. Future developments envisage giving CityZoom a more autonomous role, using artificial intelligence to optimize building shapes and dimensions.
Sport Science and Coaching in Paralympic Swimming
Authors: Burkett Brendan , Mellifont Rebecca
Published: September 2008

This research documents the sport science and coaching interaction that occurred with a national swimming team from the 2002 World Championships, 2004 Athens Paralympic Games, and the 2006 World Championships. The research was driven by the head coach of the swimming program, and biomechanical measures were made during competition and in national training camps to provide feedback to coach and athlete. By understanding the swimmers' race strategy, a 10 percent improvement in performance was attained. This was followed by an additional 2.6 percent improvement resulting in a new world record time. In addition, race-pattern comparisons were made between swimmers with visually impairment or total blindness at the Sydney 2000 Games Surprisingly, there was no difference in the race strategy between these swimmers, highlighting that the ability to “see” the opposition swimmer and racing them may not be as important as employing a suitable race strategy A key point of difference in the race analysis conducted within this research, when compared to existing research, was the use of video feedback in conjunction with the calculated race parameters.
Using Stories in Coach Education
Authors: Douglas Kitrina , Carless David
Published: September 2008

The purpose of this paper is to illustrate how storied representations of research can be used as an effective pedagogical tool in coach education During a series of continuing professional development seminars for professional golf coaches, we presented our research in the form of stories and poems which were created in an effort to evoke and communicate the lived experiences of elite professional golfers. Following these presentations, we obtained written responses to the stories from 53 experienced coaches who attended the seminars. Analysis of this data revealed three ways in which coaches responded to the stories: (i) questioning; (ii) summarising; and (iii) incorporating. We conclude that these responses illustrate the potential of storied forms of representation to enhance professional development through stimulating reflective practice and increasing understanding of holistic, person-centred approaches to coaching athletes in high-performance sport.
Collegiate Athletes' Perceptions of the Coaching Profession
Authors: Kamphoff Cindra , Gill Diane
Published: September 2008

In this study, we examined college athletes' interest in and perceptions of the coaching profession. A total of 201 U.S. Division I athletes (100 males, 101 females; 119 White, 81 minority, 1 race unknown) completed measures of a) their intention of entering the coaching profession, b) reasons they would want to enter the coaching profession, c) perceived barriers that would prohibit them from considering the coaching profession, and d) their perception of discrimination in the coaching profession. Results indicated that men were more likely than women to intend to enter coaching at the Division I and professional levels. Gender and racial differences were found in reasons for entering the coaching profession and barriers that prohibit athletes from entering the profession. Women were more likely than men to agree that male and female coaches were treated differently and minority athletes were more likely than White athletes to agree that coaches are treated differently in sport based on their race/ethnicity These results may partly explain the lack of women and minority coaches.
Sport Science and Coaching in Paralympic Cycling
Authors: Burkett Brendan J. , Mellifont Rebecca B.
Published: September 2008

This research documents the sport science initiatives of the Australian Cycling team in preparation for the 2004 Athens Paralympic Games. The research was driven by the head coach of the cycling program with biomechanical and physiological measures made during competition and/or in a controlled laboratory for six Paralympic cyclists. Half the group modified their setup with seat height decreases within a range of 10–19 mm, the other half with seat height increases within a range or 3–12 mm. All riders required seat fore/aft positioning adjustments of up to 30 mm forward to centre the knee joint over the pedal spindle. The pelvic angle rotation changed by an average of 7 degrees positive tilt (range 5–14 degrees). Relatively simple adjustments to one individual's setup reduced the cyclist's frontal-surface height by 0.22 m, with no significant change in power output. The integration of sport science with a high-performance coaching program can enhance the athlete's performance and safety. The outcomes of this specific research on elite athletes with a disability have guided the future coaching of the national team
Movement Variability and its Implications for Sports Scientists and Practitioners: An Overview
Authors: Bartlett Roger
Published: September 2008

This overview paper presents results from the studies of the various research groups with which I have been involved over the last decade that clearly show the existence of movement variability. I then address the possible functionality of movement variability. The important issue, particularly for practitioners, of whether such variability can be assessed in the conditions that pertain in competition is a major focus of the paper Unfortunately, current evidence suggests that we cannot measure movement variability in field conditions reliably or objectively, which prevents us from being able to address satisfactorily the possible implications that movement variability might pose for practitioners. Our major tasks, as sports biomechanists wishing to produce results that allow us to address issues that are relevant to coaches, are to develop accurate markerless tracking systems and to explore other measures of reliability that are more robust to measurement errors
Structural Principal Components Analysis of the Kinematics of the Soccer Kick Using Different Types of Rating Scales
Authors: Marqués-Bruna Pascual , Lees Adrian , Grimshaw Paul
Published: September 2008

Different types of rating scales have been developed to guide the qualitative analysis of sports technique and improve rating accuracy However, it remains unclear what type of scale is more accurate and how rating accuracy is influenced by scale effects. This study aimed to: I) investigate the accuracy of rating scale type (analogue, numerical analogue, Likert and numerical Likert) for the rating of kinematic variables; and ii) explore how rating accuracy is influenced by scale effects. One experienced rater constructed the 100 mm-long scales and a group of 327 novice analysts rated the video-recorded soccer kick performance of 32 school children. Estimation error was calculated as the difference between estimated values and objective digitized values. Over-and under-estimation tendencies were assessed. The scale range was divided into equal-length intervals (e.g., low, middle, high angular range) to assess scale effects Statistical analysis consisted of an exploratory principal components analysis with varimax rotation, where items were forced into a three-factor solution. Numerical Likert scale designs may be suggested as optimum for the instruction of novice raters. Central-tendency error adversely affected visual estimations; however, other scale effects enhanced accuracy. The findings have implications for optimum scale design and improved instruction in qualitative analysis.
Manipulating Constraints to Train Decision Making in Rugby Union
Authors: Passos Pedro , Araújo Duarte , Davids Keith , Shuttleworth Richard
Published: September 2008

This paper focuses on the paradoxical relationship between game unpredictability and the certainty of players' actions in team ball sports. Our research on this relationship leads us to suggest a method for training decision making, which we exemplify in the team sport of Rugby Union. The training methodology is based on application of theoretical insights from Ecological Psychology Complex Dynamical Systems and the Constraints-Led Approach. The paper starts with a critical overview of traditional approaches to studying decision making in sport. Next we describe the sport of Rugby Union to exemplify a complex dynamical system, and explain how that conceptualisation captures the interactions of players within that performance context. We conclude our analysis by describing how to manipulate task constraints to improve decision-making performance, as players search for an appropriate blend of stability and variability in their actions. In the final part of the paper, we suggest some methods to train decision making based on four stages: I) identifying the problem; ii) setting out a strategy to solve it; iii) creating an action model; and iv) building a decision-making exercise. The main conclusion from our work for coaches and sports scientists is that decision making should be improved through training methods that provide an accurate balance between stability of actions, which gives structure to the players' performance, and variability which allows them to cope with the uncertainty of situational constraints, such as the behaviour of specific opponents
Training or Education? Negotiating a Fuzzy Line between What “We” Want and What “They” Might Need
Authors: Douglas Kitrina , Carless David
Published: September 2008

In this article, we reflect on what we consider to be an over-reliance among many in golf – including coaches, sport psychologists, and governing bodies – on a training-dominated vocabulary. To do so, we adopt a narrative approach to explore: I) the kinds of stories which circulate in golf; and ii) the stories women professional golfers told of their development and progression during life history interviews. By analysing these stories, we hope to provide a contrasting perspective on golfers' long-term needs and show that alternatives to a training-dominated vocabulary are both possible and desirable. Through these reflections, we aim to present some more general insights concerning how to negotiate the fuzzy line between what “we” (as coaches, psychologists, governing body officials, performance directors, etc.) want and what “they” (players) might need in development terms. We conclude by suggesting an education-based alternative to the current training-dominated discourse which offers a healthier path to player retention, well-being, development, and progression in golf.
Temporary Correction of Transverse Plane Pelvic Rotation via a Three Minute Exercise Program
Authors: Wright David F. , Mellman Michael , Watkins Robert
Published: September 2008

A sample of 25 golfers, 12 professionals and 13 amateurs, ages 23 to 63 years, were measured for transverse plane pelvic rotation using light electrodes positioned bilaterally on the iliac crests. Transverse plane pelvic rotation was present in all of the golfers measured. All subjects were measured from a shoulder width stance, two inches wider and two inches narrower than shoulder width in a standing, erect posture and a golf set-up posture without a club. Transverse plane pelvic rotation in the 25 subjects ranged from 1 inch to 4 inches as recorded by stance correction with an average of 2.25 inches of rotation at a shoulder width stance. A dowel pole bar with light electrodes fixed to the bar was attached to the transverse pelvic plane 3 inches below the iliac crest for the purpose of validation of a measurement instrument in the field. The pelvic rotation was temporarily corrected through a simple three minute exercise program

Nineteen of the 25 subjects were seen in follow-up in the field where the dowel bar was used and they had each returned to their measured baseline pelvic rotation. Again, their measured pelvic rotation was corrected via a simple three minute exercise program The authors discuss the use of the exercise program for both golf coaching and research, and also present the validation of a simple instrument that could be used in the field to measure transverse pelvic plane rotation
A Review of Biomechanical Differences between Golfers of Varied Skill Levels
Authors: Lindsay David M , Mantrop Shannon , Vandervoort Anthony A
Published: September 2008

The purpose of this article was to review and summarize the biomechanical research literature comparing golfers of different skill levels. A golfer's skill will influence their success in being able to consistently and predictably hit the ball in the desired direction for the proper distance. By scientifically investigating the differences in swing technique between players of different abilities, golfers and golf educators should gain a better understanding of how to improve performance. Analyses of the kinetic forces, kinematic timing and sequence of the various body segments, as well as the muscle activity patterns that generate movements revealed that skilled players exhibit increased force production, efficiency and consistency relative to less skilled players. However, the variability in assorted measures even amongst skilled players, raises the question of whether there is only one ideal swing method for all individuals
The Effects of Custom-Fitted Clubs versus “Placebo” Clubs on Golf-Swing Characteristics
Authors: Bertram Christopher P. , Guadagnoli Mark A.
Published: September 2008

While the use of custom-fitted equipment is on the rise in the game of golf, empirical data as to its benefits and/or pitfalls is lacking. The current study sought to determine the effectiveness of custom-fitted clubs in the golf swing performance of both novice and experienced golfers. A launch monitor system was used to obtain measures of clubhead speed, clubface angle, and tempo to quantify baseline performance and any subsequent change in performance following the experimental procedures. Following a pre-test, which involved recording 12 swings with a standard 6-iron, participants were custom fit for club length, shaft flex, and lie angle according to the Henry-Griffitts TotalTest® system. Post-tests were administered following a 10-minute break. During the post-test, participants unknowingly used either a properly fitted club, a purposely ill-fitted (i.e., ‘placebo’ club), or the same standard club used in the pre-test. Our data suggest that custom club fitting does improve the characteristics of the golf swing, although often in different ways depending upon the skill level of the player.
Approach Shot Accuracy as a Performance Indicator for US PGA Tour Golf Professionals
Authors: James Nic , Rees Gethin D
Published: September 2008

Composite measures of golf performance, such as ‘greens in regulation,’ need to be improved upon as they cannot distinguish whether a player was good, bad or indifferent on each individual aspect of the performance, in this instance, driving and approach shots. Consequently, approach shot accuracy was assessed in terms of the distance that shots into the green finished in relation to the pin. Approach shot data (starting position, finishing position and lie) were collected from the PGA TourCast web site for 14 PGA Tour players, playing in randomly selected tournaments during 2006. Median approach shot errors (finishing distance as a percentage of starting distance) of 4.6% to 5.3% were found for fairway shots between 100 and 200 yards, rising to 6.2% to 9.6% for distances over 200 yards, suggesting some increased difficulty at longer distances. Errors tended to increase (5.2% to 6.5%) for fairway shots between 50 and 100 yards, thought to be due to the increased use of less-than-full swing shots at these distances. Shots from the rough increased the error by an average of 4.3%. It is suggested that approach shot accuracy is a viable performance indicator as it correlated strongly with World Ranking and clear individual differences allowed specific strengths and weaknesses to be ascertained. Future research should consider analysing shots from closer to the green.
Weight Transfer, Golf Swing Theory and Coaching
Authors: Jenkins Simon
Published: September 2008

This article is primarily concerned with issues raised by the “Stack and Tilt” method of teaching the golf swing and recent scientific research on weight transfer. Concepts related to weight transfer are discussed in the context of golf swing theory and the art of golf coaching. An explanation for the paradoxical success of “Stack and Tilt” is proposed along with a future agenda for scientific research on weight transfer. Both golf coaches and sports scientists should understand the importance of Ben Hogan's golf swing and instructional book, The Modern Fundamentals of Golf, as an exemplar for golf swing theory. In addition, the role of qualitative analysis of human movement in facilitating quantitative biomechanics is emphasized.
Distance Variability in Golf Putting among Highly Skilled Players: The Role of Green Reading
Authors: Karlsen Jon , Nilsson Johnny
Published: September 2008

The purpose was to quantify how important green reading, technique and green surface inconsistencies were for distance variability in putting among highly skilled players. Forty-three players (mean handicap = 2.8, s = 2.2) participated in the study. Their average relative distance variability (expressed as standard deviation) was s = 10.6% on a test including 40 different putts from 2.2 to 19.3 m, and s = 6.8% on the last 15 putts in a test with 30 repeated 6 m putts in the same direction. Relative distance variability caused by green surface inconsistency was s = 2.5%. A variance analysis of the putt data, based on assumptitions which lead to a conservative estimate of the importance of green reading, revealed that the relative importance of the determining factors for distance variability was: Green reading (60%); technique (34%); and green inconsistency (6%). In conclusion, it seems beneficial for highly skilled players to put higher emphasis on green reading in distance control practice, and that coaches and researchers should focus more on developing methods and training programs for improving the green reading skill.