科创中国

以CNKI数据库收录的(2002-2011年)10年高等职业教育方面的研究论文为数据源,利用SPSS、Excel、Uncient、Netdraw等软件.对文献中的高频关键词进行聚类分析、多维尺度分析和中心度分析.结果表明,这一阶段我国高等职业教育研究的热点主要包括人才培养模式、示范性、课程设置、校企合作、工学结合等.教育教学质量、绩效、国际化等将成为高等职业教育未来研究趋势.

依据微博信息资源对企业产品信息进行监测,可以使企业更好地了解用户的相关信息.监测的基本步骤为:采集相关用户的描述标签与相关博文,对标签和博文分别进行聚类,从而发现兴趣社区与相关热门话题.其后以某一知名微博系统为平台,以某一品牌为例,进行相应的实证研究,结果表明所提方法具有一定的实践价值.

目的 探讨男性尿道狭窄患者的心理社会因素及其影响.方法 选择符合标准的男性尿道狭窄患者30例,与同周期健康男性做对照研究.结果 SCL-90评定提示男性尿道狭窄患者的心理健康状况明显低于对照组.Eysenck个性问卷调查表明,男性尿道狭窄患者的E分低于对照组,N分、L分高于对照组,P分无统计学差异.说明与健康人群相比较,男性尿道狭窄患者性格偏于内向(E分较低),情绪不够稳定.易怒、好焦虑、紧张(神经质,N分值高)且好掩饰(L分高).男性尿道狭窄患者的社会支持总分低于对照组健康人群.结论 男性尿道狭窄患者的心理健康状况较差.根据这一情况,制定相应的干预方法,对其身心健康恢复起重要作用.

The intermittent connection(IC)of the field-bus in networked manufacturing systems is a common but hard troubleshooting network problem,which may result in system level failures or safety issues.However,there is no online IC location identification method available to detect and locate the position of the problem.To tackle this problem,a novel model based online fault location identification method for localized IC problem is proposed.First,the error event patterns are identified and classified according to different node sources in each error frame.Then generalized zero inflated Poisson process(GZIP)model for each node is established by using time stamped error event sequence.Finally,the location of the IC fault is determined by testing whether the parameters of the fitted stochastic model is statistically significant or not using the confident intervals of the estimated parameters.To illustrate the proposed method,case studies are conducted on a 3-node controller area network(CAN)test-bed,in which IC induced faults are imposed on a network drop cable using computer controlled on-off switches.The experimental results show the parameters of the GZIP model for the problematic node are statistically significant(larger than 0),and the patterns of the confident intervals of the estimated parameters are directly linked to the problematic node,which agrees with the experimental setup.The proposed online IC location identification method can successfully identify the location of the drop cable on which IC faults occurs on the CAN network.

Forming limit curves(FLCs) are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are non-negligible under warm/hot stamping conditions. To investigate the experimental errors, experiments for obtaining the FLCs of the AA5754 are conducted at 250℃. Then, FE models are created and validated on the basis of experimental results. A number of FE simulations are carried out for FLC test-pieces and punches with different geometry configurations and varying friction coefficients between the test-piece and the punch. The errors for all the test conditions are predicted and analyzed. Particular attention of error analysis is paid to two special cases, namely, the biaxial FLC test and the uniaxial FLC test. The failure location and the variation of the error with respect to the friction coefficient are studied as well. The results obtained from the FLC tests and the above analyses show that, for the biaxial tension state, the friction coefficient should be controlled within 0.15 to avoid significant shifting of the necking location away from the center of the punch; for the uniaxial tension state, the friction coefficient should be controlled within 0.1 to guarantee the validity of the data collected from FLC tests. The conclusions summarized are beneficial for obtaining accurate FLCs under warm/hot stamping conditions.

The existing researches of the evaluation method of ride comfort of vehicle mainly focus on the level of human feelings to vibration. The level of human feelings to vibration is influenced by many factors, however, the ride comfort according to the common principle of probability and statistics and simple binary logic is unable to reflect these uncertainties. The random fuzzy evaluation model from people subjective response to vibration is adopted in the paper, these uncertainties are analyzed from the angle of psychological physics. Discussing the traditional evaluation of ride comfort during vehicle vibration, a fuzzily random evaluation model on the basis of annoyance rate is proposed for the human body's subjective response to vibration, with relevant fuzzy membership function and probability distribution given. A half-car four degrees of freedom suspension vibration model is described, subject to irregular excitations from the road surface, with the aid of software Matlab/Simulink. A new kind of evaluation method for ride comfort of vehicles is proposed in the paper, i.e., the annoyance rate evaluation method. The genetic algorithm and neural network control theory are used to control the system. Simulation results are obtained, such as the comparison of comfort reaction to vibration environments between before and after control, relationship of annoyance rate to vibration frequency and weighted acceleration, based on ISO2631/1(1982), ISO 2631–1(1997) and annoyance rate evaluation method, respectively. Simulated assessment results indicate that the proposed active suspension systems prove to be effective in the vibration isolation of the suspension system, and the subjective response of human being can be promoted from very uncomfortable to a little uncomfortable. Furthermore, the novel evaluation method based on annoyance rate can further estimate quantitatively the number of passengers who feel discomfort due to vibration. A new analysis method of vehicle comfort is presented.

关于我国农民工的福利与社会政策问题,已有的研究多专注于实际状况与问题,从一定的理论视角出发进行的研究并不多.综合考量以往研究成果以及我国农民工面临的问题后建立的农民工社会政策决定分析框架,有助于对我国进入新世纪以来国家关于农民工社会政策的转变进行分析.近年来,我国各级政府在农民工政策选择转向中发挥了较大作用,但中央政府责任承担过少,对于地方政府的激励、约束措施不足,导致政策实施效果差强人意.因此,今后农民工社会政策的实践效果与社会权利的平等获得,在很大程度上取决于中央政府的责任承担,包括在中央层面的组织机构、制度创新以及资源供给上作出适当安排.

Existing biped robots mainly fall into two categories: robots with left and right feet and robots with upper and lower feet. The load carrying capability of a biped robot is quite limited since the two feet of a walking robot supports the robot alternatively during walking. To improve the load carrying capability, a novel biped walking robot is proposed based on a 2-UPU+2-UU parallel mechanism. The biped walking robot is composed of two identical platforms(feet) and four limbs, including two UPU(universal-prismatic-universal serial chain) limbs and two UU limbs. To enhance its terrain adaptability like articulated vehicles, the two feet of the biped walking robot are designed as two vehicles in detail. The conditions that the geometric parameters of the feet must satisfy are discussed. The degrees-of-freedom of the mechanism is analyzed by using screw theory. Gait analysis, kinematic analysis and stability analysis of the mechanism are carried out to verify the structural design parameters. The simulation results validate the feasibility of walking on rugged terrain. Experiments with a physical prototype show that the novel biped walking robot can walk stably on smooth terrain. Due to its unique feet design and high stiffness, the biped walking robot may adapt to rugged terrain and is suitable for load-carrying.

The classical natural coordinate modeling method which removes the Euler angles and Euler parameters from the governing equations is particularly suitable for the sensitivity analysis and optimization of multibody systems. However, the formulation has so many principles in choosing the generalized coordinates that it hinders the implementation of modeling automation. A first order direct sensitivity analysis approach to multibody systems formulated with novel natural coordinates is presented. Firstly, a new selection method for natural coordinate is developed. The method introduces 12 coordinates to describe the position and orientation of a spatial object. On the basis of the proposed natural coordinates, rigid constraint conditions, the basic constraint elements as well as the initial conditions for the governing equations are derived. Considering the characteristics of the governing equations, the newly proposed generalized-α integration method is used and the corresponding algorithm flowchart is discussed. The objective function, the detailed analysis process of first order direct sensitivity analysis and related solving strategy are provided based on the previous modeling system. Finally, in order to verify the validity and accuracy of the method presented, the sensitivity analysis of a planar spinner-slider mechanism and a spatial crank-slider mechanism are conducted. The test results agree well with that of the finite difference method, and the maximum absolute deviation of the results is less than 3%. The proposed approach is not only convenient for automatic modeling, but also helpful for the reduction of the complexity of sensitivity analysis, which provides a practical and effective way to obtain sensitivity for the optimization problems of multibody systems.

针对文本中冗余的欠缺,造成在文本中隐藏信息量少而难以实现隐密信息的传输,提出了一种基于聊天表情符号的信息伪装新方法,应用于网络聊天中以增加隐蔽性.该方法简单实用、可操作性强,实验证明,该算法具有良好的不可见性和安全性,容量也较为理想,达到信息伪装的目的.