A competing Markov model for cracking prediction on civil structures

Cracks on the surface of civil structures (e.g. pavement sections, concrete structures) progress in several formations and under different deterioration mechanisms. In monitoring practice, it is often that cracking type with its worst damage level is selected as a representative condition state, while other cracking types and their damage levels are neglected in records, remaining as hidden information. Therefore, the practice in monitoring has a potential to conceal with a bias selection process, which possibly result in not optimal intervention strategies. In overcoming these problems, our paper presents a non-homogeneous Markov hazard model, with competing hazard rates. Cracking condition states are classified in three types (longitudinal crack, horizontal crack, and alligator crack), with three respective damage levels. The dynamic selection of cracking condition states are undergone a competing process of cracking types and damage levels. We apply a numerical solution using Bayesian estimation and Markov Chain Monte Carlo method to solve the problem of high-order integration of complete likelihood function. An empirical study on a data-set of Japanese pavement system is presented to demonstrate the applicability and contribution of the model.     

土体中应力分布基本规律的探讨

基于土体的颗粒结构和只有颗粒接触传递应力的特性，对不同姿态颗粒接触中应力传递的机理分析，揭示了土体在相对静态下存在主动力的应力扩散效应和强被动力的应力集中效应，及其形成的土体中应力分布基本规律。主动力的应力场是以其所在土层的应力扩散角θ向外扩散的园锥形应力范围，在应力场内应力扩散分布，主应力方向不变，且伴有与之垂直的法向应力，应力分布均衡了应力场内颗粒和支承面的位移趋势。强被动力的支承面上存在以θ角向外扩散倒锥台形的应力平衡范围，在此范围内反向应力集中作用到强支承面，强支承面主导了其所在应力场的应力分布。土拱效应是应力集中效应的衍生效应，是相邻的同向强支承反力的应力平衡范围发生重迭时产生的现象。     

连锁零售业库存／配送一体化决策优化模型与算法

针对在一个区域内拥有一个配送中心和n个在地理位置上分散的连锁分店的连锁零售业．建立VMI思想下适合于A类商品和一些重要的B类和C类商品的单一商品确定型需求的库存／配送一体化优化模型，并采用逐步迭代的方法对模型进行求解，可得出使系统在一定时期总成本最小的经济订购批量，最后用一个算例使连锁零售业库存，配送一体化决策在物流成本节约方面的优越性得以验证。     

加强供应链管理 构建节约型社会

以我国能源短缺为切入点,认为实施供应链管理可以使企业降低成本、创造竞争的整体优势,实现供求间的良好合作,为建设循环经济奠定基础。以实例说明了供应链管理给企业带来的显著经济效益。最后指出开展供应链管理对构建节约型社会、实现经济的可持续发展有重大意义。     

The influence of food quality on the nutritional acclimation of the copepod Acartia clausi

The influence of food quality on the nutritional metabolism of Acartia clausi was studied experimentally using four different diets: (1) diatom cells of Thalassiosira weissflogii, (2) detritus prepared from the same culture, (3) 50 : 50 mix on a protein basis of the two previous diets, and 4) dinoflagellate cells of Prorocentrum micans. For each trophic, ingestion, gut transit time, trypsin activity and K_m (half saturation constant) were measured at limiting and saturating concentration. Assimilation rates were also estimated for both pure diatoms and mixed live–detrital cell diets. Ingestion followed a Holling type 2 response for diets 1 and 4, a linear one for detritus and an intermediate response for diet 3. Gut transit time displayed different adaptive changes with food regime depending on protein concentration. Trypsin activity was lower for detrital food and trypsin K_m significantly decreased with increasing concentration of live diatoms. Assimilation rates were higher for live food than for mixed live–detrital food. Results illustrated that Acartia-type copepods optimize nitrogen or protein uptake. They suggest that besides chemoreception-mediated selectivity, internal controls by digestion and assimilation also regulate ingestion (feed-back).     

连锁经营是汽车维修业的发展方向

在我国汽车维修行业发展连锁经营是整个行业生存的必由之路。在介绍了国外的汽车维修连锁企业的基础上,论述了发展连锁经营的必要性和紧迫性,并对我国汽车维修连锁企业的发展提出了一些合理化建议。     

Travel Behavior Analysis of the Females in Beijing

In urban life, compared with the same age group of male contrast, the statistical indicators of female travel behavior show significant differences. According to the sample data of Beijing 2005 travel survey, the paper analyzes the female travel behavior in the travel rate, travel consumption, trip purpose, and travel mode. Furthermore, the paper introduces the concept of the trip chain, to construct a female morning commuter trip chain choice behavior model with noncollection theories and methods, to analyze 10 factors that influence a female individual's choice of a trip chain from the source. Subsequently, model parameters are estimated, to calculate the incidents that can help to quantitatively understand the impact of each factor on a female's choice of the trip chain. The results show that the travel rate of elderly women is far lower than that of elderly men. Female travel proportion in shopping and social activities is obviously higher than that of male travelers, and factors related to the structure of families create important constraints in their average travel time consumption. The main travel mode of the female is walking, which is far more than that of a male. Age, whether they hold licenses, monthly income, and transport ownership are dominant factors for the female's choice of the trip chain.     

面向供应链的虚拟企业利润分配机制研究

随着专业分工和信息技术的发展,产业组织结构对企业效益和成本有极大的影响。揭示了虚拟企业的组织结构模型及其企业行为特征,建立了虚拟企业的供给模型,提出了虚拟企业联盟的两种利益分配机制,分析了这两种分配机制的合理性,为虚拟企业的实现创造了条件。     

基于Shapley值法的港口冷链物流投资分析方法

从客户的角度出发,旨在建立一套与投资额度、客户满意程度相关联的港口冷链物流投资分析方法,为决策者在财务分析之外提供另一个分析视角。将港口冷链物流划分为冷藏存储、冷藏加工、冷藏运输、客户服务4个环节。首先利用层次分析法确定各个环节在整条供应链的权重,然后引入效用理论确定各个环节投资产生的效用,通过Shapley值法实现了各个环节在整条供应链权重和各个环节投资效用的有机结合,使得发展瓶颈随投资的变动而改变,从而更加符合实际情况。通过实例分析,此方法能够充分考虑投资效用的影响,也能够减少专家打分等定性方法产生的主观偏差。     

基于博弈论的供应链金融监管合同奖惩研究

将银行和物流监管公司签订的监管合同中的奖惩条款为研究对象,基于博弈论探讨了监管方和借款方的博弈行为,找到了纯粹决策和混合决策的纳什均衡。通过算例,对比计算了有无奖励和惩罚时,混合决策的纳什均衡点的差异性:当在合同中增加奖励和惩罚措施时,纳什均衡的点将离原点更远,双方将以更大的概率选择合作。以此为基础,科学设立监管合同中监管项目的评价指标体系,明确监管奖惩措施,将有效降低供应链金融风险。