机载适航标准DO-178B/C软件计划过程研究

介绍了DO-178B/C标准的发展历程,结合对DO-178B/C标准软件生命周期过程的研究,从活动、子过程转段及顺序、生命周期环境、其它因素、开发标准、计划满足DO-178B/C要求以及计划的开发与修正等7个方面对软件计划过程进行了研究,并对关注点进行了分析,最后展望了DO-178B/C标准的未来研究方向.     

世界文化遗产“突出的普遍价值”评价标准的演变

围绕《保护世界文化与自然遗产公约》中的文化遗产概念,对1977年至今以来不同版本的《实施世界遗产公约的操作指南》中,世界文化遗产“突出的普遍价值”评价标准的修订过程进行研究,分4个历史时期梳理了突出的普遍价值概念、评价标准、真实性和完整性条件、特殊类型遗产列入导则的主要变化,分析了标准修订的进步与局限,归纳了导致标准修...     

Le monde de la pratique

The Green Building Materials '96 (GBM '96) conference brought manufacturers of building materials and products into the process of defining what may be called ‘green building materials’. Forty-seven manufacturers and associations presented information on environmental and associated quality criteria of their products. In addition, materials analysis and certification, building design, implementation, information sources and marketing were discussed. Charles J. Kibert and Gisela Bosch report.     

实施CIM的评价准则

计算机集成制造（ＣＩＭ）在国际上已经实施２０多年了。我国的ＣＩＭ研究工作也已经开展了１０年。国际上对ＣＩＭ的看法众说纷纭，据国外的某些统计报道，有的企业实施ＣＩＭ取得了巨大成果，而更多的企业实施效果却不理想。如何评价企业实施ＣＩＭ的必要性和正确性已成为这一领域的重要课题。然而，由于其本身的复杂性，迄今为止，在文献中还找不到可以适用于多数ＣＩＭ企业、又为大家普遍接受的评价方法。我们总结了近年来在国内的ＣＩＭ实践，又基于中欧合作对ＣＩＭ方法论的研究，在此提出一套ＣＩＭ评价的准则和方法，希望它能在企业作出实施ＣＩＭ的决策时，对企业有一定的引导作用。     

Experimental study on impact absorbing performance of motorcycle helmets

The regulation regarding motorcycle helmets to protect the head from impacts has been amended recently. In Europe, the Head Injury Criteria (HIC), which is more relevant to indicate the probability of death than the limitation of maximum acceleration, has been adopted. An experimental study has been conducted following the procedure of the new European regulation, by changing various helmet structural parameters such as the lamination and the bulk density of the shell, and the liner, to investigate the ability of the helmet to protect the head from injuries. The maximum acceleration and HIC were measured. Experimental data have been analyzed with respect to varying lamination of shells and weight of liners. The HIC was found to be improved by reducing the bulk density of the liner and the number of laminations of a shell, and by increasing the loading area of the headform.     

关于知识研究的历史成果之批判与继承

1.知识研究的历史与现状 1.1从哲学领域开始 早在古希腊时期,哲学家就已经开始研究讨有关知识的种种问题了,因此在哲学领域蕴藏着丰富的研究成果,历代哲学家的许多思想,今仍具有重要的参考价值。例如,古希腊的哲学家苏格拉底     

Double-level languages and co-operative working

Four criteria are discussed as important conditions of successful applications in Computer Supported Co-operative Work (CSCW). They are equality, mutual influence, new competence, and double-level language. The criteria originate in the experience of the International Co-operative Movement. They are examined and illustrated withreference to eight contemporary CSCW applications: meeting scheduling and support; bargaining; co-authoring; co-ordination; planning; design support and collaborative design.     

肿瘤特征基因选择的互信息最值过滤原则与粒子群优化算法

基因数据小样本、高维数、高冗余的特点常导致特征基因选择出现"维数灾难"和"过拟合",针对这一问题,提出一种特征基因提取算法——互信息最值过滤原则-惯性权重粒子群优化（MIMVFC-IWPSO）算法。首先,借鉴过滤法的思路,通过计算互信息指标,依据互信息最值过滤原则（MIMVFC）获得特征基因候选子集（FGCS）,缩小分类操作的范围,提高特征基因被覆盖的概率;接着,对粒子群优化（PSO）算法进行改进,引入惯性权重实现自调节可变惯性权重粒子群优化（IWPSO）算法,使得在算法迭代初期有着快速的全局优化能力,而在算法后期具有较强的局部搜索能力;最后,运用IWPSO从FGCS中提取核心信息基因子集（CFGS）,并基于CFGS对样本进行肿瘤与正常组织的分类。采用3个公开的肿瘤基因表达谱数据进行实验,MIMVFC正确分类率优于信噪比（SNR）、t-检验和信息增益（IG）方法,与卡方统计值（Chi-Square）方法接近,而MIMVFC还能利用IWPSO进一步优化结果。基于相同的FGCS,与目前效果较好的二进制粒子群优化与防治基因算法（BPSO-CGA）相比,IWPSO的运算耗时有所增加,但所获得的CFGS规模减小,准确率提高;而与经典PSO相比,所获得的CFGS规模减小、运算耗时减少、准确率提高。实验结果表明MIMVFC-IWPSO具有较好的综合分类性能,能有效提高准确率和效率,可用于多种肿瘤的特征基因选择,辅助指导分子生物学实验设计和验证。     

Revisit submergence of ice blocks in front of ice cover–an experimental study

The present paper studies the stabilities of ice blocks in front of an ice cover based on experiments carried out in laboratory by using four types of ice blocks with different dimensions. The forces acting on the ice blocks in front of the ice cover are analyzed. The critical criteria for the entrainment of ice blocks in front of the ice cover are established by considering the drag force caused by the flowing water, the collision force, and the hydraulic pressure force. Formula for determining whether or not an ice block will be entrained under the ice cover is derived. All three dimensions of the ice block are considered in the proposed formula. The velocities calculated by using the developed formula are compared with those of calculated by other formulas proposed by other researchers, as well as the measured flow velocities for the entrainment of ice blocks in laboratory. The fitting values obtained by using the derived formula agree well with the experimental results.     

Effect of body-borne equipment on injury of military pilots and aircrew during a simulated helicopter crash

Military helicopter pilots are expected to wear a variety of items of body-borne equipment during flight so as to be prepared for any situation that may arise in combat. Helicopter seats are designed to a specified weight range for an occupant with equipment. This paper investigates how distributing the equipment on the body affects injury potential during a helicopter crash. A finite element model representing a helicopter seat with a fully deformable 50th percentile Hybrid III carrying equipment was developed. The model was subjected to a standard military certification crash test. Various equipment configurations were investigated and analysed to determine its influence on the risk of injury. It was found that placing the equipment low on the torso, i.e. near the thighs, not only reduces the likelihood of injury in the lumbar, spinal region but also provides favourable results in neck and head injury risk when compared to other configurations investigated. In contrast, placing equipment high on the torso, i.e. close to the chin, increases the lumbar load and implicitly, the risk of head injury. A statistical analysis is carried out using the Wilcoxon Signed Rank Test to deliver probability of loads experienced within a certain interval. This study recommends an equipment configuration that improves survivability for an occupant seated on a fixed load energy absorbing seat which is subjected to Military Standard 58095A Test 4.