基于仿真技术的物流中心站台数确定方法研究

通过建立描述站台数量的模型,利用排队论理论得到了最优站台数的解法,同时利用Arena仿真软件对这一问题进行仿真。应用Arena仿真克服了理论建模方法的不足,为物流中心最优站台数问题提供了一种较为理想的解决方法。     

The aggregation of capital over vintages in a model of embodied technical progress

The paper considers how to measure capital in a model where technical progress is embodied in new units of capital. This embodiment model also assumes that once new units of capital are installed, it cannot be “unbolted” and sold on the second hand market. A significant difference between this Solow–Harper model and the traditional capital services model due to Jorgenson and his coworkers is that rising real wage rates will generally induce early retirement of assets; i.e., this model can provide an explanation for obsolescence. The paper studies how to aggregate over vintages and how to measure depreciation in the context of this embodiment model. These problems are more complicated than the corresponding problems in the traditional capital services model because the age of retirement of an asset is endogenous in the embodiment model. The paper uses duality theory to simplify the exposition.

The impact of the net percentage growth rate in the number of small firms on differential state-level employment growth rates in the US: an exploratory empirical note

This brief exploratory empirical note seeks to identify key determinants of geographic differentials in the percentage growth rate of state-level employment in the US, with the primary focus being on the percentage net growth rate in the number of small firms (i.e., those with fewer than 20 employees) in each state, where this variable serves as a de facto reflection of ‘entrepreneurship’. In the interest of identifying other key factors that influence state-level employment growth rates, the effective income tax rate in each state, quality of life elements and labour market considerations are also included in the analysis. The study period runs from the year 2000 to the year 2007, ending just prior to the ‘Great Recession’. The estimation results imply that the state-level employment growth rate in the US was an increasing function of the percentage net growth rate in the number of small firms in each state. Thus, it appears that the small firms growth rate may in fact be a significant source.     

基于人机环境的链杆平衡模型在施工中的应用

根据在建筑工程的施工进度项目管理中人、机、环境等因素对施工进度的影响程度,应用项目管理中决策树的数学思想,建立人、机、环境一体化的链杆平衡管理建筑工程施工进度控制模型,研究了我国施工企业在施工项目进度控制方面的综合资源平衡问题,发现利用综合能力数来评价人、机、环境一体化对施工项目进度的影响,能有效地发挥人、机、环境一体化管理对施工过程进行控制的效应,从而使得施工项目进度最大限度的得以实现,并通过调整各分项工程的综合能力数来优化及合理分配资源。     

壳聚糖对紫花地丁复合饮料保质期的影响

本试验以感官评定、菌落总数、pH值和DPPH自由基清除能力为指标,探究不同浓度的壳聚糖溶液处理对以紫花地丁和大麦为主要原料的复合饮料的保质期影响.结果表明,壳聚糖添加量在1.5％时饮料的感官评分较高,菌落总数的增长受到有效抑制,pH值下降受到抑制,具有良好的抗氧化稳定性.研究结果可为紫花地丁复合饮料的研发试验提供理论基...     

基于区间数向量投影的主要防御方向选择

一种基于区间数向量投影的主要防御方向选择方法。针对评价指标属性和权重的区间数,构造正理想方案,计算各方案在正理想方案的投影值,根据投影值完成方案的排序优选。实例分析验证了其有效性和适用性。     

提高汽油辛烷值的方法研究

文章从工艺、油品调和及添加剂的使用几个方面提出了提高汽油辛烷值的方法,并作做简单分析。     

直觉梯形模糊几何集成算子及其在群决策中的应用

文章首先定义了直觉梯形模糊数及其运算法则,基于这些运算法则,给出了直觉梯形模糊几何集成算子,即直觉梯形模糊加权几何(IT-WG)算子、直觉梯形模糊有序加权几何(IT-OWG)算子以及直觉梯形模糊混合几何(IT-HG)算子。在此基础上,提出了在属性权重已知的情形下专家评价值以直觉梯形模糊信息给出的多属性群决策方法。最后以产品最优设计方案的选择为实例进行分析,所得结果验证了该方法的有效性。     

FIPIA with information entropy: A new hybrid method to assess airline service quality

This study proposes “FIPIA with information entropy” as a new, hybrid method to assess airline service quality by identifying the most important priorities for airline passengers and producing recommendations to airline management for optimal resource allocation to improve service quality and customer satisfaction. The proposed method is an improvement over IPA, IPIA and FIPA methods, through the introduction of information entropy and fuzzy logic to the analysis of importance, performance and impact dimensions of airline service quality to improve interpretability and actionability of analysis results. This study also offers airline managers a list of what they should improve in resource allocation in order to increase service quality considering customer satisfaction and create value by managing the relational capital more effectively. The new hybrid method was field-tested by administering a 26-item questionnaire to passengers of a major airline operator, analyzing the responses using the Importance-Performance-Impact Analysis (IPIA) method, fuzzy logic and information entropy. The analysis revealed four main dimensions of airline service quality, namely reliability, assurance, tangibles, empathy and responsiveness with 17 constituent attributes. The case study revealed that (1) resource allocation was adequate only on four attributes; (2) seven service quality attributes were identified as needing further management focus on resource allocation; (3) six service quality attributes received more resources than necessary which should be shifted to other attributes; (4) dimensions of reliability and tangibles needed more focus than others. The proposed hybrid method of FIPIA with information entropy can be employed for any industry where service quality depends on multiple attributes.     

Entry and the Number of Firms in the Swedish Pharmaceuticals Market

This paper analyses the factors that determineentry into the Swedish pharmaceuticals market. The analysis is based onpanel data for 22 different substances covering the years 1972 to 1996. Theresults show that profit opportunities in a particular market have apositive impact on entry. In addition, there is some evidence suggestingthat the length of the patent protection period has a negative impact onentry.