Bedingungen der Bindungswirkung inkrementeller Normen in Fußballvereinen

Sports clubs depend on the pooling of resources by their members. The supportive distribution of the resources within a club is facilitated in particular by the effectiveness of incremental standards. A basic prerequisite for a fair distribution of resources is a minimum of community spirit among the members. Based on a nationwide survey of football clubs and an ordinal logistic regression model, factors were determined that reflect the extent of the community spirit within a club. The opening up of the club by payment to players and perceived problems with acquiring and binding of volunteers are associated with a reduction of community spirit. In contrast, the perception that the club activities can be continued in the long term shows a positive correlation to a highly developed community spirit.     

A channel distortion model for video over lossy packet networks

Error-resilient video communication over lossy packet networks is often designed and operated based on models for the effect of losses on the reconstructed video quality. This paper analyzes the channel distortion for video over lossy packet networks and proposes a new model that, compared to previous models, more accurately estimates the expected mean-squared error distortion for different packet loss patterns by accounting for inter-frame error propagation and the correlation between error frames. The accuracy of the proposed model is validated with JVT/H.264 encoded standard test sequences and previous frame concealment, where the proposed model provides an obvious accuracy gain over previous models.     

太阳能空间斯特林热机性能的优化分析

建立太阳能驱动的空间斯特林热机的循环模型，应用有限时间热力学理论和太阳能集热器的辐射损失模型，研究受热阻和回热损失影响的太阳能斯特林热机循环性能，导出空间热机效率的基本优化关系，确定太阳能集热器的最佳工作温度和效率界限，讨论各种不可逆性对空间热机性能的影响，所得结论可为太阳能空间斯特林热机的优化设计提供新的理论指导。     

GPS/GIS车辆监控管理系统中的关键技术

简要论述了车辆监控管理系统的工作原理及通信链路的选择策略，针对一套实用的GPS／GIS车辆监控系统设计方案，详细阐述了系统设计中的关键技术．     

A review of tennis racket performance parameters

The application of advanced engineering to tennis racket design has influenced the nature of the sport. As a result, the International Tennis Federation has established rules to limit performance, with the aim of protecting the nature of the game. This paper illustrates how changes to the racket affect the player-racket system. The review integrates engineering and biomechanical issues related to tennis racket performance, covering the biomechanical characteristics of tennis strokes, tennis racket performance, the effect of racket parameters on ball rebound and biomechanical interactions. Racket properties influence the rebound of the ball. Ball rebound speed increases with frame stiffness and as string tension decreases. Reducing inter-string contacting forces increases rebound topspin. Historical trends and predictive modelling indicate swingweights of around 0.030–0.035 kg/m² are best for high ball speed and accuracy. To fully understand the effect of their design changes, engineers should use impact conditions in their experiments, or models, which reflect those of actual tennis strokes. Sports engineers, therefore, benefit from working closely with biomechanists to ensure realistic impact conditions.     

Synchronized lower limb kinematics with pelvis orientation achieves the non-rotational shot

A non-rotational (NR) shot is now a well-known scoring move in soccer. To execute the NR shot, it is necessary to deprive the ball of any rotational forces during the impact phase. To execute the NR shot, it is natural that the force vector acting from the foot would pass through the ball’s center of gravity; however, the coordinated motion of the lower limb joint’s angular displacement and the pelvis is still unclear. The aim of this study is to estimate the coordinated leg and pelvis motion during the NR shot as compared to that during instep kicking. Four right-leg dominant college league players were asked to perform a NR shot and an instep kick a total of 10 times each. Hip, knee, and ankle joint angular displacements in the sagittal plane and pelvis yaw and roll rotational motions during both types of kicks were calculated with 14 IR reflective markers using a 3D real-time motion analysis system with a 250-Hz sampling. The Euclidean distances of the joint space of the NR shot and the instep kick were also calculated to detect similarities in the coordinated motion of the lower limb. The results showed that the lower limb joint motions in the sagittal plane were not different; however, the pelvis roll and yaw motions were apparently different, and these phenomena could simulate a pendulum motion with changes in both the vertical and horizontal displacements. These results suggest that the coordinated motion of the lower limb joint’s angular displacement shows high similarity between the NR shot and the instep kick, and the pelvis roll and yaw synchronized orientation is essential for achieving the NR shot.     

Elite wheelchair rugby: a quantitative analysis of chair configuration in Australia

Limited recommendations of wheelchair configurations for court sports have been identified in the published literature. To accommodate the wide range of impairments in wheelchair rugby, players are given a point score that reflects their impairment. Players have regularly been grouped as high-, mid-, or low-point players in research, with high-point players having greater levels of muscle function compared with other classifications. This research documented the wheelchair configurations of elite Australian wheelchair rugby players across classification groups. Significant differences (p < 0.05) were found for increased seat height and decreased seat depth for high-point players compared with low- and mid-point groups, respectively. Low-point players displayed reduced wheelchair mass compared with high- and mid-point players, as well as increased frame length. Camber angles showed no significant differences across the classification groups. The incorporation of anthropometric measures, such as the elbow angle at the top dead center, was also investigated. While elbow angle showed no significant differences, seat height-to-total arm length ratio was higher for high-point players. Participants also completed surveys detailing their perception of the effect of altering wheelchair configurations. It is suggested that wheelchair configurations should consider an individual’s anthropometrics, impairment, training history, and court role to promote optimal performance, with predictive modeling having the potential to reduce the associated time and cost.     

Direct skeletal attachment prosthesis for the amputee athlete: the unknown potential

Lower limb amputees often experience complications with the use of conventional socket-type prostheses, which further reduce their already compromised ability to perform the activities of daily living, or to participate in sporting activities. During the last two decades, a new technology of direct skeletal attachment (osseointegration) of prosthesis to the femoral residuum has been developed. The aim of this research was to assess the implant design, surgery protocols, and functional testing of this new technology on the first 100 patients using the Integral Leg Prosthesis procedure. This new knowledge can guide future engineering developments of osseointegration within the sporting arena. Between 1999 and 2013, direct skeletal implantation was performed on 112 amputees, from two centres in Germany and Australia. From the experience of the surgical team, modifications were made to the implant design. This re-engineering of the implant has reduced the surgical revisions due to infection from 29 % with the early implant design down to 7 %. The functional testing of the 34 Australian cases were assessed pre- and 12 months post-implant with significant improvements of one complete K-scale; the Q-TFA measures increased (50.9–86.7), whilst the Timed Up and Go decreased significantly (12.43 s ± 3.89 to 8.03 s ± 2.80), and the 6 min walk increased (304.0–383.9 m). From these findings, osseointegration technology is realistically the way of the future for amputee athletes. Further refinement of the implant design and sports-specific functional testing are required to define the potential of this technology.     

Effect of blended learning and learners’ characteristics on students’ competence: An empirical evidence in learning oriental music

Blended learning emerged as the most popular instructional design strategy in the field of education since last decade to present date. In fact, it is well acknowledged that blended learning approach significantly elevate students’ engagement and competency in learning process. Despite immense potentiality, many countries are still lag behind adopting this instructional design, such as Sri Lanka. Therefore, the primary aims of this study are two fold, (a) to investigate the effect of blended learning and learners’ characteristics on students’ competence and (b) to investigate the effectiveness of blended learning in teaching Oriental Music. This study mainly carried out among the senior secondary schools students at Colombo, Sri Lanka. A mixed methods, experimental and survey, were carried out to test the effectiveness of blended learning and identifying the important factors for enhancing students’ competence in learning Oriental Music. Results of independent sample t-test confirmed that blended learning is effective in terms of improving students’ performance in learning Oriental Music. Similarly, regression analysis confirmed that attitude and motivation are the two most important determinants for improving students’ competence. This study fulfilled an existing research gap by utilizing blended learning to teach highly traditional abstract art. Results of the study contributes to the curriculum designing field with novel ideas to adapt in hybrid instructions to teach secondary level students effectively. The curriculum designers will make use of these findings during innovation and future researcher would be benefitted to overlook more possible platforms to deliver music instructions. It will help them to understand how their set objectives have been achieved in technology integrations and seek for improvement where necessary.     

易燃木炭的分析与制备研究

目的:利用松木废料制作安全环保的易燃木炭。方法:松木废料碳化成木炭粉,与配制好的氧化剂、连接剂均匀混合,压制成型后90℃干燥80 min,制得易燃木炭,试验研究NaOH含量对连接性能的影响及硝酸钾和高锰酸钾的配比对助燃效果的影响。结果:25%氢氧化钠10 mL水解5 g淀粉,然后加入1.25 g KNO_3及0.5 g KMnO_4混合助燃剂与7.5 g木炭粉混合制得产品,并利用傅立叶变换红外光谱仪和扫描电镜对易燃木炭进行分析。结论:实验室制备的易燃木炭,较购买的易燃木炭具有更高热值,安全性高且更环保。