再论建设项目的投资控制

合理确定建设项目投资控制的目标，做好决策阶段、设计阶段的投资控制以及主动控制各阶段对建设项目的投资控制均具有十分重要的作用，此外，还必须加强技术与经济的相结合，正确处理好二者之间的关系，这样才能切实地将控制项目投资概念渗透到各项工作中去。     

作业成本计算流程与模型构建

作业成本计算法是以作业为基础的成本核算方法，它建立在“作业消耗资源，产品消耗作业”两个前提下，是一种比较准确的成本计算方法。在作业成本法的基本原理的基础上，设计出了作业成本的计算流程，并结合矩阵理论建立了作业成本计算的数学模型。     

铜钝化废液的再生回收与循环利用

本文提出了一种铜钝化废液再生回收与循环利用的工艺方法隔膜电解法，这种方法把电解和膜分离技术融为一体。论文对方案选择、再生回收原理、工艺条件的确立等都进行了认真地讨论。     

Strategies and determinants for successful space technology transfer

The following paper reports the results of a research work carried from 2008 on the topic of strategies and determinants of space technology Transfer (TT). In particular, the aim of this study is to present: 1. The policies and strategies the major space agencies adopt for TT, 2. The operational mechanisms and determinants involved in the transfer of space technologies to other industrial sectors. To this extent we have conducted in the last five years: six case studies of large space agencies, four TT case studies concerning the construction of scientific satellites, two case studies focused on space to earth TT programs undertaken by the Japanese aerospace agency, and two TT case studies examining Italian space companies.The comparative and comprehensive analyses of these studies indicate that the space agencies of the more industrialized countries aim primarily at consolidating and developing the industrial systems in their own countries, which include the use of technology transfer programs, and that the transfer of space technologies follows the route “Earth–Space–Earth”. With regard to the determinants of the TT process, the most important of these correlate with the type of technology in transfer, whereas organizational, economic and financial determinants have less significance.     

一种优先级区分的机载无线网络MAC层自适应退避算法

针对现有无线网络媒介接入控制(MAC)协议退避机制存在的竞争窗口(CW)易产生振荡、不能为紧急业务提供低时延QoS保障、难以区分服务类别等不足,提出了一种区分业务优先级的自适应退避(PAB)算法。该算法在二进制指数退避(BEB)算法的基础上,根据信道忙闲标识和业务优先级自适应选择相应退避阶段,通过参数设置可对不同优先级业务相邻退避阶段的前、后转移概率进行调整。利用二维马尔可夫链理论对PAB进行了建模分析,理论分析获得了饱和吞吐量和平均MAC时延的数学表达式,仿真实验结果表明:在机载无线网络(AN)环境下,PAB的性能相对BEB有了显著提升,可有效保障机载无线网络多业务类型的传输需求。     

变量相关情况下基于马尔可夫链样本模拟的线抽样可靠性灵敏度分析方法

针对变量具有相关性的可靠性灵敏度分析问题,提出了一种变量相关情况下基于马尔可夫链样本模拟的线抽样可靠性灵敏度分析方法。在所提方法中,首先将相关变量等价转换为独立正态变量,然后采用基于马尔可夫链样本模拟的线抽样方法,求解失效概率对等价独立正态变量分布参数的偏导数,最后利用等价变换前后变量分布参数之间的解析关系和复合函数求导法则,求得失效概率对相关变量分布参数的可靠性灵敏度。为了解所提方法的效率和精度,对所提方法的可靠性灵敏度估计值进行了方差分析。由于所提方法采用马尔可夫链快速产生失效域中的条件样本,这些失效域中的样本可用来准确获取重要方向,并可作为线抽样的随机样本,因而该方法具有很高的抽样效率。算例结果表明,所提方法是一种计算相关变量可靠性灵敏度的高效率、高精度方法。     

Contributions of the International Space Station towards future exploration missions

When the idea of a large space station in Low Earth Orbit (LEO) was conceived in the 1980s, it was primarily planned as an orbiting laboratory for microgravity research. Some even thought of it as an industrial plant in space. Whereas the latter did not materialize because of various reasons, the former is absolutely true when you talk about the International Space Station (ISS). Since the transition to a six astronaut crew in 2009 and the completion of its assembly in 2011, it has been intensively used as laboratory in a wide field of scientific topics. Experiments conducted on ISS have yielded first class results in biology, physiology, material science, basic physics, and many more. While its role as a laboratory in space is widely recognized, the awareness for its potential for preparing future exploration missions beyond LEO is just increasing. This paper provides information on how the ISS programme contributes to future exploration efforts, both manned and unmanned. It highlights the work that has been done or is currently underway in the fields of technology, operations, and science. Further potentials and future projects for exploration preparation are also shown. A special focus lies on experiments and projects primarily funded by the German Aerospace Center (DLR) or with strong German participation in the science team.     

双轴模拟式太阳敏感器测试链误差分析及修正

基于四象限硅光电池,双轴模拟式太阳敏感器（简称双轴模太）可实现太阳矢量两轴方向角的同时测量。硅光电池各象限光生电流的采集精度直接决定了敏感器的工作性能。然而,测试链环节中存在的不一致性误差会引起双轴模太角度测量偏差。为此,基于数值仿真,分析并建立了硅光电池各象限响应率、各象限光生电流的电压转换、信号放大、A/D转换系数及暗电流等环节偏差的影响模型,进而对各环节的综合偏差进行标定和修正,从而在保证敏感器测量精度的同时,降低对测试链环节的要求。测试结果表明,在不改变测试链性能的情况下,双轴模太的测量精度由修正前的2.05° (α轴,3σ)和1.94° (β轴,3σ)提高到0.28° (α轴,3σ)和0.26° (β轴,3σ)。     

基于控制论的3种供应链动态特性比较

基于自动控制理论,以APIOBPCS(Automatic Pipeline, Inventory and Order Based Production Control System)订货系统为基础,采用模拟仿真的方法,考察传统二级供应链(TSC,Traditional two-echelon Supply Chain)、需求信息共享(DIS,Demand Information Sharing)二级供应链和供应商管理库存(VMI,Vendor Managed Inventory)这3种典型二级供应链系统在阶跃需求信息时,不同系统参数对系统订单、在制品量和库存量的影响,并对3种系统的动态响应特性进行了对比研究.研究结果表明:对于阶跃需求信息,生产提前期T_p越小,系统响应峰值越小,响应速度越快;参数T_i,T_w和T_a在不同范围内对系统峰值和调节时间的影响趋势有所不同,需要根据供应链整体目标进行选择.而且一种供应链系统往往不能兼顾系统的响应峰值和调节时间两个特性,应综合考虑响应峰值和调节时间对系统整体绩效的影响,选择适当的管理策略优化供应链系统,以提高供应链的整体运行效率.