有限反馈预编码优化中基于性能准则的码字选择

多输入多输出(MIMO)空分复用系统中,采用有限比特反馈方式设计最优预编码矩阵,使用较少的反馈开销,可以有效地提高系统性能。对于有限反馈预编码设计方案,提出了一种基于Qos准则的码字选择方法,以最优化系统MSE性能和BER性能为目标选择最佳码字。仿真结果表明,与已有的码字选择方式相比,本文提出的方法更加直接,对于各种码本具有通用性,而且进一步改善了有限比特反馈预编码的性能,系统BER值降低了1.5 dB。     

大学校服设计水平调查

本文针对大学生这个特殊群体,采用问卷调查与谈话相结合的方式,对目前大学生校服的设计进行了调查。结果表明,校服的款式、颜色、质量等方面都存在较大问题。对此提出五点建议,希望能对大学校服的设计制作和在我国的推广起到一定作用。     

论火力发电厂循环水泵房出水管抗推部分的结构设计

文章以某2×300MW机组火力发电厂循环水泵房为例，介绍了循环水泵房结构出水管抗推部分的设计方法。     

Modeling and optimizing the integrated problem of closed-loop supply chain network design and disassembly line balancing

This paper describes an integrated model that jointly optimizes the strategic and tactical decisions of a closed-loop supply chain (CLSC). The strategic level decisions relate to the amounts of goods flowing on the forward and reverse chains. The tactical level decisions concern balancing disassembly lines in the reverse chain. The objective is to minimize costs of transportation, purchasing, refurbishing, and operating the disassembly workstations. A nonlinear mixed integer programming formulation is described for the problem. Numerical examples are presented using the proposed model.     

Global supply chain design: A literature review and critique

In this paper, we review decision support models for the design of global supply chains, and assess the fit between the research literature in this area and the practical issues of global supply chain design. The classification scheme for this review is based on ongoing and emerging issues in global supply chain management and includes review dimensions for (1) decisions addressed in the model, (2) performance metrics, (3) the degree to which the model supports integrated decision processes, and (4) globalization considerations. We conclude that although most models resolve a difficult feature associated with globalization, few models address the practical global supply chain design problem in its entirety. We close the paper with recommendations for future research in global supply chain modeling that is both forward-looking and practically oriented.     

考虑环境因素的货运航线网络优化设计

针对传统货运航线网络设计中仅考虑经济目标而忽视环境影响的问题,在绿色民航的背景下,提出一种综合考虑经济目标和环境影响的货运航线网络优化方法。基于多分配严格枢纽航线网络,以经济成本、CO2、CO和NOx排放量最小为目标,构建相应的数学模型。采用线性加权和法与分支定界法结合案例求解。结果显示,不同优化目标下的航线网络结构存在一定差异,难以同时达到最优。与仅考虑经济成本的求解方案相比,采用本文的综合求解方案,能够实现经济效益和环境效益间的较好均衡。     

我国民营银行市场准入问题初探

为维持体制内的增长,政府实行了垄断性金融制度安排。这一安排在改革初期对经济增长起到了推进作用。但随着时间的推移,其边际成本已经超过了边际收益,加之我国已加入WTO,银行业向民营资本开放的时机已经成熟。现在重要的是设计好民营银行的经营框架,主要包括地区选择、资本结构和分级管理三个方面。     

浅析我国个人所得税改革中的问题及对策

个人所得税是对自然人取得的各项应税所得征收的税种,在聚集财政收入、公平收入分配方面发挥着巨大作用.个人所得税关系到每一个自然人的切身利益.对我国个人所得税现状的分析表明,随着我国经济体制改革的不断推进,市场经济的建立和完善,经济发展水平与综合国力的明显提高,现行个人所得税运行机制逐步显露出征收模式不科学,税率设计不合理,起征点不公平,征收管理不严密等一系列缺陷.为进一步改革和完善个人所得税制,更好地发挥个人所得税在组织收入、公平分配与调节经济中的重要作用,应进一步完善个人所得税征收基础制度;建立科学的预扣预缴税款制;推行双向申报制度;拓宽税基,降低税率;重点稽查,加大处罚.     

Models and optimal designs for conjoint choice experiments including a no-choice option

In a classical conjoint choice experiment, respondents choose one profile from each choice set that has to be evaluated. However, in real life, the respondent does not always make a choice: often he/she does not prefer any of the options offered. Therefore, including a no-choice option in a choice set makes a conjoint choice experiment more realistic. In the literature, three different models are used to analyze the results of a conjoint choice experiment with a no-choice option: the no-choice multinomial logit model, the extended no-choice multinomial logit model, and the nested no-choice multinomial logit model. We develop optimal designs for the two most appealing of these models using the D-optimality criterion and the modified Fedorov algorithm and compare these optimal designs with a reference design, which is constructed while ignoring the no-choice option, in terms of estimation and prediction accuracy. We conclude that taking into account the no-choice option when designing a no-choice experiment only has a marginal effect on the estimation and prediction accuracy as long as the model used for estimation matches the data-generating model.