Comparing Numerical Methods to Estimate Vertical Jump Height Using a Force Platform

ABSTRACT

Males (n = 29) and females (n = 34) performed vertical jumps. Jump height was estimated from force platform data using five numerical methods and compared using intraclass correlation (ρ), and linear and rank regression standard error of estimate (SEE). Take-off velocity plus center of mass height at take-off and mechanical work methods were identical (ρ = 1.000) with small linear (SEE < 0.0001 cm) and rank order (SEE = 0) error. Integrating acceleration to displacement was nearly identical (ρ > 0.999), with small linear (SEE = 0.1 cm) and rank order (SEE < 1) errors compared to the above methods. Take-off velocity (ρ = 0.517) and flight time (ρ = 0.573) estimates were less than all other methods and had large linear (SEE ≥ 2.1 cm) and rank order (SEE > 4) errors. Take-off velocity and flight time methods should be avoided due to systematic and random error.     

若干力学参数对跳远成绩的影响

本文建立了考虑空气阻力时，跳远运动员空中运动的微分方程，根据量阶比较，求得该方程的适定解。与以往所发表的不考虑空气阻力时的远度公式比较，定量讨论风速，空气密度，重力加速度等力学参数对跳远成绩的影响量值。     

论运动竞技的新趋势

当今世界上风行着摩托车、汽车、摩托艇和飞机等运动机械竞技活动。这是一种以人机联合体为竞技主体的运动竞技项目，是工业文明时代人的活动方式在竞技领域的反映，代表着世界竞技运动发展的一种新趋势。     

Phase Diagram Calculation and Fabrication of Multi-component Zirconia-Based Ceramics

Ceria-yttria co-doped zirconia-based multi-compo-nents ceramics,with superfine alumina dispersed inthe matrix,possess excellent fracture toughness,strength and thermal stability.However,the mechani-cal properties and microstructure are strongly depen-dent on the composition and the fabrication proce-dure,especially the composition of zirconia containingmulti-component ceramics.Therefore,precise phasediagrams of zirconia-based multi-components systemscan be considered as the“map”for the devel…     

探讨产生式系统求解过河游戏

作先提出一个智力游戏－－过河游戏，并利用人工智能中的产生式系统去分析和求解该智力游戏，最后用FOXBASE＋实现，为求解这类游戏提供了一种途径。     

高强混凝土高温作用后的力学性能研究

通过对高温后高强混凝土力学性能的试验研究,探讨了高强混凝土的抗压强度、抗拉强度和抗折强度在不同温度下的变化规律,分析了温度对高强混凝土力学性能的影响机理、爆裂现象、爆裂机理,最后,对进一步的研究进行了展望。     

Development of mechanical engineering curricula at the University of Minho

The implementation of the Bologna protocol in the European Union has set new goals for the whole higher education system as: (a) a quality assessment for university courses; (b) a framework for the exchange of students and academics; and (c) an opportunity for changing the teaching/learning procedures and methodologies. Within the context, the mechanical engineering curricula at the University of Minho have been comprehensively formulated in order to meet these and future challenges and expectations. The whole process has been based upon various cornerstones: the legal framework for the higher education system; the introduction of new learning methodologies and an accurate survey and understanding of the existing strong and week points of the previous experience. For this purpose, a comprehensive evaluation has been carried out with former students and a detailed map has been formulated regarding their professional careers and experiences. Furthermore, a discussion has been carried out in order to define the mission of the graduate in mechanical engineering. In brief, such mission may be referred by his ability to participate in the wealth creation through technology based innovation. Within this context, the curriculum has been structured in order to meet such goals. In addition to strong foundations in physics and mathematics, new subjects are introduced into the curriculum. The whole education is based upon project development which stimulates the students' initiative, responsibility and their ability to integrate knowledge. Throughout the curriculum, students are enrolled into research projects developed in the department and it is expected that a few selected projects may be taken into a quasi industrial stage.     

Bibliographically coupled patents: Their temporal pattern and combined relevance

Bibliographically coupled patents reveal a temporal pattern associated with their ages (how long ago they have been issued) and spans (their distance in time). The coupling strength of the aged or long-spanned patent pairs may be inherently limited, especially for fields that reveal patent and reference expansions. This study proposes a simple measure, combined relevance (CR), to counter such impact. Unlike traditional measures, CR provides more balanced treatment to short- and long-spanned but favors more aged patents pairs. A fixed CR threshold may be more safely applied with a reduced possibility of erroneously removing patent pairs that are truly related. For observing long-term knowledge dissemination or tracing overall development trajectory, CR may be an alternative.     

竞技陀螺旋转体系的力学分析与技战术运用

运用文献研究、观察、专家咨询、逻辑分析等方法,以竞技陀螺比赛攻守过程中处于旋转体系下陀螺的受力情况为研究对象,对处于旋转体系下的陀螺攻守过程进行力学分析,并以此为基础对竞技陀螺攻守技战术运用进行探讨。结果表明：1）利用陀螺旋转体系的回动效应,运动员训练可有意识地旋放出活陀螺和流动陀螺。根据两个旋转体系的碰撞效应,守方运动员可借助对旋放区陀螺旋放落点的控制实现防守的战术意图,而攻方运动员则可以借助进攻力量、攻击部位、旋转性质的变化调整进攻技法。2）守方选手加强陀螺旋转的稳定性和旋放区前缘、后缘、左缘、右缘、中央等五个区域的落点以及活陀螺、流动陀螺、死陀螺各种旋放技术的训练,从旋转稳定性、落点意识、不同陀螺的旋放技术等方面提高防守能力;攻方运动员可掌握重击打法、轻钓打法两种进攻技术,控制己方陀螺旋转性质,进攻对手陀螺不同部位等进攻技巧,并提高进攻的准确性和稳定性及战术素养。     

画法几何及土木工程制图的教学改革探讨

画法几何及土木工程制图作为土木工程专业的专业基础课,同时土木工程专业也是一门实践性需求很高的学科专业;因此,遵循传统的教学模式无法满足应用型人才培养的目标,这也是当前画法几何及土木工程制图教学的困难之处。以此为切入点,提出教改措施和方法,真正满足应用技术人才培养的土木工程专业的工程制图教学。