科创中国

在科技中介服务市场上,非营利性科技中介机构不仅可以强化政府的公共服务职能,提高公共服务的效率,还可以有效避免市场失灵问题,维护科技中介市场环境的稳定.目前我国非营利性科技中介机构却存在缺乏核心竞争力、独立性差、资金来源渠道单一等诸多问题.为了实现非营利性科技中介机构的稳健发展,提出了4个方面的对策:完善其发展机制、引导社会力量积极参与、发展社会公益基金、制定政策法规等.

对档案利用服务质量的评价不能只停留于综合档案馆的自我评价,社会公众即档案利用者才是档案利用服务质量评价的主体力量.本文从利用者本位的视角出发,尝试提出了一种社会公众参与的档案利用服务质量评价的指标体系和评价量表,以期推动综合档案馆档案利用服务质量的规范化管理.

基于PKI的WTLS协议涉及复杂的证书操作,需耗费较大的通信和计算开销,且缺乏对服务器证书的有效性检查.引入可信证书验证代理(TCVP)和证书有效性凭据(CVT)等概念,由TCVP为无线通信节点(WN)生成短时有效的CVT,WN通过交换CVT来完成证书的有效性检查和公钥交换.基于此,提出了一种通用无线认证协议(GWAP).在GWAP框架下,采用ECC算法设计了一种具体的无线安全认证协议,并进行了效率分析.结果表明,该协议在确保安全的前提下降低了通信开销.

在以往的服务管理研究中,服务绩效的影响因素很多,然而没有文献研究员工对服务的概念性界定对服务绩效的影响.基于行为识别理论,文章提出服务认知一行为模式对一线员工的服务绩效存在影响.该研究利用旅行社业和饭店业402名一线服务员工的问卷调查数据,部分验证了所提出的假设,实证结果发现:(1)对顾客理解型服务认知一行为模式具有最高的角色外服务绩效,对工作规范型服务认知一行为模式具有最低的角色外服务绩效;(2)对工作规范型服务认知一行为模式具有最低的角色内服务绩效,对顾客理解型和手段型服务认知一行为模式具有较高的角色内服务绩效.

目前存在大量异构的SOA平台,不同平台下WebService标准繁多且技术复杂,因此,异构平台Web Service的安全交互成为急待解决的问题,而SOAP消息的安全性是决定Web Service安全的重要因素.本文针对异构平台间SOAP消息的安全性问题,提出了基于WebSphere和.NET异构平台间消息传递的安全处理模型,该模型采用基于逻辑谓词的方法实现异构平台的安全策略集成,使用集成安全策略对SOAP消息进行签名和加密处理.通过实验验证,该模型保证了SOAP消息在异构平台间传递的安全性,实现了异构平台间WebService的安全交互.

Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height.This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism.Assuming the constraints between the supporting feet and the ground with hinges,the supporting legs and the hexapod body are taken as a parallel mechanism,and each swing leg is regarded as a serial manipulator.The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground.Locomotion performance can be got by analyzing these equivalent mechanisms.The kinematics of the whole robotic system is established,and the influence of foothold position on the workspace of robot body is analyzed.A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle.Referring to service region and service sphere,weight service sphere and weight service region are put forward to evaluate the dexterity of robot body.The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated.Simulation shows when the foothold offset goes up to 174 mm,the dexterity of robot body achieves its maximum value 0.164 4 in mixed gait.The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot,and provide new approach to determine the stride length,body height,footholds in gait planning of multi-legged robot.

分析专业图书馆实现知识服务转型的4个主要方面及对图书馆人员结构的需求,包括建设多元化数字资源保障体系、探索面向专业领域的知识服务模式、试验开展集成化知识环境建设、创建柔性灵活的团队与协作机制.结合以国家科技文献中心成员单位为代表的专业图书馆人员队伍结构,分析其人员队伍状况,阐明专业图书馆人员结构与未来发展存在业务布局、专业能力、信息技术水平、组织管理体制等方面的差距.

Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries.The two kinds of actuators can replace each other in most fields,such as the point to point transmission occasion and some rotating occasions.However,there are very few research results about the advantages and disadvantages of two kinds of actuators under the same working conditions so far.In this paper,a novel comprehensive assessment method,named as overall life cycle comprehensive assessment(OLCCA),is proposed for comparison and assessment of pneumatic and electric actuators.OLCCA contains mechanical properties evaluation(MPE),life cycle cost analysis based on users(LCCABOU)and life cycle environmental impact analysis(LCEIA)algorithm in order to solve three difficult problems:mechanical properties assessment,cost analysis and environmental impact assessment about actuators.The mechanical properties evaluation of actuators is a multi-objective optimization problem.The fuzzy data quantification and information entropy methods are combined to establish MPE algorithm of actuators.Two kinds of pneumatic actuators and electric actuators with similar bearing capacity and similar work stroke were taken for example to verify the correctness of MPE algorithm.The case study of MPE algorithm for actuators verified its correctness.LCCABOU for actuators is also set up.Considering cost complex structure of pneumatic actuators,public device cost even method(PDCEM)is firstly presented to solve cost division of public devices such as compressors,aftercooler,receivers,etc.LCCABOU method is also effective and verified by the three groups of pneumatic actuators and electric actuators.Finally,LCEIA model of actuators is established for the environmental impact assessment of actuators.LCEIA data collection method and model establishment procedure for actuators are also put forward.With Simapro 7,LCEIA comparison results of six actuators can be obtained:Fossil fuels are the major environmental factor of pneumatic and electric actuators;Environmental impact of electric actuator is large than one of pneumatic actuator under the similar mechanical properties and working conditions of pneumatic and electric actuators.The results are correct and correspond with the actual mechanical properties of actuators.This paper proposes a comprehensive evaluation method of the actuators,which can solve the critical problem that similar electromechanical products are very difficult to be compared with each other from the angle of performance,cost and environment impact.

美国公共行政理论中的管理主义范式经历了萌芽、形成、拓展和成熟四个发展阶段.实证主义是管理主义的哲学基础,因为实证主义为管理主义提供了方法论基础,而管理主义是实证主义在管理领域的具体应用.美国公共行政理论中的管理主义是在与宪政主义的争论中得以发展和完善的,其理论体系由单一化、片面化逐渐走向多元化、系统化;理论研究由注重经济、效率价值转向既注重经济、效率价值,又兼顾人本价值,这是美国公共行政理论中管理主义发展的内在逻辑.

Lightweight design requires an accurate life prediction for structures and components under service loading histories. However, predicted life with the existing methods seems too conservative in some cases, leading to a heavy structure. Because these methods are established on the basis that load cycles would only cause fatigue damage, ignore the strengthening effect of loads. Based on Palmgren-Miner Rule(PMR), this paper introduces a new method for fatigue life prediction under service loadings by taking into account the strengthening effect of loads below the fatigue limit. In this method, the service loadings are classified into three categories: damaging load, strengthening load and none-effect load, and the process for fatigue life prediction is divided into two stages: stage I and stage II, according to the best strengthening number of cycles. During stage I, fatigue damage is calculated considering both the strengthening and damaging effect of load cycles. While during stage II, only the damaging effect is considered. To validate this method, fatigue lives of automobile half shaft and torsion beam rear axle are calculated based on the new method and traditional methods, such as PMR and Modified Miner Rule(MMR), and fatigue tests of the two components are conducted under service loading histories. The tests results show that the percentage errors of the predicted life with the new method to mean life of tests for the two components are –3.78% and –1.76% separately, much lesser than that with PMR and MMR. By considering the strengthening effect of loads below the fatigue limit, the new method can significantly improve the accuracy for fatigue life prediction. Thus lightweight design can be fully realized in the design stage.