Measurement of active drag during crawl arm stroke swimming

In order to measure active drag during front crawl swimming a system has been designed, built and tested. A tube (23 m long) with grips is fixed under the water surface and the swimmer crawls on this. At one end of the tube, a force transducer is attached to the wall of the swimming pool. It measures the momentary effective propulsive forces of the hands. During the measurements the subjects' legs are fixed together and supported by a buoy. After filtering and digitizing the electrical force signal, the mean propulsive force over one lane at constant speeds (ranging from about 1 to 2 m s-1) was calculated. The regression equation of the force on the speed turned out to be almost quadratic. At a mean speed of 1.55 m s-1 the mean force was 66.3 N. The accuracy of this force measured on one subject at different days was 4.1 N. The observed force, which is equal to the mean drag force, fits remarkably well with passive drag force values as well as with values calculated for propulsive forces during actual swimming reported in the literature. The use of the system does not interfere to any large extent with normal front crawl swimming; this conclusion is based on results of observations of film by skilled swim coaches. It was concluded that the system provides a good method of studying active drag and its relation to anthropometric variables and swimming technique.     

从“规律”的证实到意义的解释:教育学的语义转向

教育学自从成为一门独立的学科以来 ,一直以证实教育领域中的“客观规律”为己任 ,以便使其成为一门所谓的“科学教育学”。然而 ,教育学的科学化追求却是以牺牲其内在的意义、价值与逻辑、依据为代价的 ,通过机械地移植自然科学的方法、标准而进行的 ,从而造成教育学知识属性的扭曲。这是今日教育学危机四伏的根本原因。因而 ,拯救教育学的命运 ,我们必须重新认识教育学的知识属性及其科学化标准 ,并使教育学从对外在的、僵化的“客观规律”的证实转向内在的意义、价值及逻辑、依据的解释     

知识管理与企业流程管理的融合

从信息管理系统与企业流程重组入手,分析知识管理与企业流程管理之间关系;引入协同概念,阐述协同概念分别与知识管理以及企业流程管理的关系。     

试论图书情报学创新教育

图书情报学创新教育是２１世纪知识经济社会对图书情报学教育的客观要求,同时也是图书情报学教育主动回应知识经济挑战在教育理念上的变革。图书情报学创新教育要求教育创新,即在教育理念、教育内容、教学方法与手段、教育评价体系、教师素质要求等方面创新。     

创新型文化与企业绩效关系的实证研究

本文通过对45家企业的512名员工进行问卷调查收集数据,采用路径分析法验证创新型文化、文化强度对企业绩效的影响。结果表明:创新型文化通过影响企业新产品/服务开发速度。对企业财务绩效、总体竞争力有显著正向效果;文化强度对企业财务绩效、总体竞争力有显著正向效果。     

企业竞争力的探讨

从国内外企业竞争力的研究现状出发，提出若干可资借鉴的研究角度：企业竞争力的形成一环境的关系、企业资源系统的协调运作形成企业竞争力、企业的内在和外部竞争力。在此基础上，从八个方面评价企业的竞争能力。结合中国企业的发展现状，进行更学入、更系统的企业竞争力研究做一铺垫。     

电子商务环境下ERP系统的发展与整合

ERP系统以管理的全面性、系统性,以及绩效显著,在发达国家得到广泛应用与推崇,并在我国也得到了一定程度的应用与发展。本文从系统工程的角度对电子商务环境下的ERP进行了分析与研究,提出了电子商务与ERP整合的方向与策略,为企业在电子商务活动中ERP的运用提出了有益建议。     

高校学科团队创新绩效决定因素研究

构建了团队创新绩效决定因素模型，并对86个高校学科团队的660名教师进行问卷调查，从个体层面验证了该模型。结果显示：领导能力、领导行为、成员创新能力、成员创新行为、团队工作偏好、组织内创新环境等因素对团队创新绩效有显著正效果；团队互动和团队创新气氛的中介作用显著。提出了提高团队创新绩效的建议。     

Robust stable pole-placement-based adaptive control of continuous linear systems with two parametrical estimation schemes

This paper deals with the pole-placement-type robust adaptive control of continuous linear systems in the presence of bounded noise and a common class of unmodeled dynamics provided that two estimation schemes are used in parallel. Both estimation schemes are introduced in order to minimize the plant identification error by selecting, as plant parameter estimates, a convex combination of both parameter estimates which leads to the selection of one of the estimation schemes, via a switching rule, on time intervals of at least a minimum prefixed residence duration. The weights of the individual parameter vector estimates are provided at each time by an optimization or suboptimization scheme for a quadratic loss function of the possibly filtered tracking error and/or control input. The robust stability of the overall adaptive scheme is ensured by an adaptation relative dead zone which takes into account the contribution of the unmodeled dynamics and bounded noise. The basic results are derived for two different estimation strategies which have either a shared regressor with the plant or individual regressors for the input contribution and its contributed derivatives. In this second case, the plant input is obtained from a similar convex combination rule as the one used for the estimators in the first approach. An extension of the basic strategies is also pointed out including a combined use of the (sub) optimization scheme with a supervisor of past measures for the on-line calculation of the estimator weights in the convex combination. Finally, the extension of the scheme for the use of any number of parametrical estimators is focused on.