大规模邻域搜索算法求解时变车辆调度问题

对时变网络车辆调度问题提出一种满足先入先出准则的时变处理方法,并建立相应的数学模型,提出一种基于大规模邻域搜索技术的智能优化算法进行求解,算法顶层采用动态规划算法搜索环状交换邻域以得到每辆车的最佳服务顾客集合;底层设计动态搜索算法用以安排每辆车的最佳服务路线.在此基础上提出顶层加入虚拟顾客和底层嵌入insert两类改进策略.通过实验仿真比较,验证了所提算法的有效性.     

有限缓冲区的多节点订单接受模型与算法

订单接受问题广泛存在于生产管理中,而现有多节点订单接受问题中大多不考虑缓冲区约束对订单接受的影响。针对这一问题,以缓冲区约束的多节点生产为背景,建立了订单接受模型。利用改进NEH算法、离散和声搜索算法和变邻域搜索的混合算法对模型进行求解。实验结果显示,当问题规模较小时,算法取得较好的计算效果。问题规模较大时,求解效果一般。缓冲区的大小对订单完工时间影响较小,与无限缓冲区的计算结果相似。混合算法具有较好的求解速度,能够有效求解问题模型。     

BAB算法中集成CPT求解job-shop调度问题

CSP(constraintsatisfactoryproblem)的优势在于能够处理复杂约束,获得一个满足约束的解,但难以保证解的质量.OR(operationresearch)的优点是获得最优解或近优解,但它求解复杂约束的优化问题非常困难.CPT(constraintpropagationtechnique)是CSP的主要搜索技术,BAB(branch_and_bound)是OR常用的优化算法.提出了一种将CPT集成于BAB中的混合算法,从一个新的角度解决具有一般性与挑战性的job shop调度问题.其主要特点是,通过在BAB算法中嵌入动态可调的时间窗口约束和加强一致性CPT搜索方法,融合BAB的优化能力和CPT处理复杂约束的能力,提高BAB的优化性能及实际应用能力.实验结果令人满意,证明了算法的有效性.     

作业时间依赖顺序的拆卸线平衡多目标优化

在废旧产品拆卸时无先后关系约束的任务之间可能存在拆卸干扰，使任务作业时间依赖于拆卸顺序，导致产品总作业时间不确定，从而影响拆卸线的平衡。为此，考虑拆卸过程中任务间的相互干扰，以最小化拆卸成本和环境危害为目标，构建作业时间依赖顺序的拆卸线平衡多目标优化模型，并提出一种Pareto人工蜂群算法进行求解，采用混合生成法保证种群质量与多样性，设计变邻域深度搜索策略以提高雇佣蜂局部开采效率，为降低侦察蜂探测的盲目性采用基于外部存档的单点变异算子进行搜索。最后通过算例与实例验证算法的有效性以及平衡任务在拆卸线上分配的重要性。     

基于自适应大邻域搜索的鲁棒多项目调度方法

多项目资源管理有时需要采用一种资源专享-转移策略，该策略下可更新资源在多项目之间不共享，但在当前项目完工之后其资源可以转移至其它还未开始的项目。针对这一实际问题的理论研究非常有限。考虑活动工期的不确定性，从时差效用函数视角评价项目调度计划的鲁棒性，在考虑拖期成本-鲁棒性的多目标问题框架下，构建了一个资源专享-转移视角下的多项目资源分配(战术层)与鲁棒调度(运作层)双层决策优化模型。针对模型的NP-hard性质和多目标组合优化特征，设计了一种新的自适应大邻域搜索(adaptive large neighborhood search，ALNS)算法求解模型。该算法采用“项目-缓冲-资源-活动”列表的混合编码表示问题可行解，提出基于四类列表的destroy-repair邻域结构，设计一种超体积指标进行自适应搜索以提高算法性能。最后，为了验证ALNS算法的适用性和有效性，设计一种NSGA-II算法作为比较基准，通过大规模仿真实验对算法性能进行了对比分析，并探索工期不确定水平对多项目调度方案鲁棒性的影响。     

考虑通行约束和运力限制的灾后应急物资联合调度优化研究

考虑到灾后路网受损难以运输应急物资，本文研究了应急响应中车辆-直升机联合调度的路径优化问题。针对受灾地区的实时路况，通往灾区的救援工具受到数量以及装载量的约束，本文将受灾点等待救援的平均时间最短以及应急网络总费用最低设为目标，构建运力受限条件下带通行约束的救援物资联合运输多目标优化模型，然后根据随机邻域搜索变异和分级交叉的思想构建出一种带精英策略的非支配排序混合进化算法（NSHEA-II）得到模型的解，并利用算例分析对该算法进行可行性检验。结果发现，本文构建的NSHEA-II算法相对NSGA-II算法能够得到较好的结果且波动性较小，这为决策者制定救援物资的配送方案提供有效的技术支撑。     

混合PSO算法求解混装工艺下的加热炉调度问题

针对钢铁生产中为减轻混装的影响在冷热板坯混装处空炉的情况,以提高成品质量、降低能耗为目标,建立了混装工艺下并行加热炉调度的数学模型,并提出了基于粒子群算法和邻域搜索技术的混合算法,仿真实验验证了算法的可行性和有效性.     

一种求解双目标flow shop排序问题的进化算法

提出一种求解双目标flow shop排序的递进多目标进化算法.算法采用改进的精英复制策略,在实现精英保留的前提下降低了计算复杂性;通过递进进化模式增加群体多样性,改善了算法收敛性;通过群体进化过程中对非劣解集进行竞争型可变邻域启发式搜索,增强了算法局部搜索性能.采用新算法和参照算法NSGA-II对31个标准双目标flow shop算例进行优化.研究结果表明,新算法在所有算例的求解中均获得了优于NSGA-II的非劣解集,验证了算法的有效性.     

有顾客时间窗和发货量变化的紧急车辆调度研究

对紧急车辆调度系统进行了研究,探讨了紧急车辆调度问题实现的关键技术.对有顾客时间窗和发货量变化的紧急车辆调度问题,运用了禁忌算法(TS)进行优化.算法基于实数编码,应用GENI插入法产生初始解和进行邻域操作,设计了三种邻域,利用容量约束控制单条路径配送点数,采用惩罚函数处理时间窗约束,通过设计虚拟车场等方法实现了车辆的紧急调度.本文给出了一个具有代表性的算例试验结果,算例结果及其分析表明了此方法对优化紧急车辆调度问题的有效性.     

动态需求下车辆路径问题的周期性优化模型及求解

针对客户点不断更新的动态需求车辆路径问题,依据滚动时域对配送中心工作时间进行划分,提出基于延迟服务的周期性客户点实时重置策略,策略中延迟服务机制能结合车辆启动延迟系数对照当前时域的时间进行检验,满足所有客户点的服务需求,保证车辆满足中心时间窗约束。设计多阶段求解的混合变邻域人工蜂群算法对各时间片内子问题进行连续迭代优化,算法中子路径动态转变的设计能较好平衡原有客户点和新客户点对路径更新和车辆实时信息匹配的要求。算例验证及对比分析表明本文策略和算法在求解动态问题时的有效性和可行性。     

Inventory Models with Continuous and Poisson Demands and Discounted and Average Costs

We develop a new, unified approach to treating continuous‐time stochastic inventory problems with both the average and discounted cost criteria. The approach involves the development of an adjusted discounted cycle cost formula, which has an appealing intuitive interpretation. We show for the first time that an (s, S) policy is optimal in the case of demand having a compound Poisson component as well as a constant rate component. Our demand structure simultaneously generalizes the classical EOQ model and the inventory models with Poisson demand, and we indicate the reasons why this task has been a difficult one. We do not require the surplus cost function to be convex or quasi‐convex as has been assumed in the literature. Finally, we show that the optimal s is unique, but we do not know if optimal S is unique.     

Educational Landscapes and Urban Development. Contextual and Spatial Interfaces and Linkages

In the broad sociopolitical discussion on education quality within the last decade, it has become apparent that education is gaining importance for urban development, as well as space and the urban context are important dimensions of education. This becomes particularly evident in concepts for local educational landscapes (Ger. Bildungslandschaften). The young field of research on educational landscapes is currently lacking empirical research from spatial and planning sciences. In the paper, the current state of scientific research on educational landscapes in Germany and Europe and first insights to contextual and spatial interfaces and linkages between education and urban development in general are presented.     

CEO and Chairperson characteristics and firm performance

This paper focuses on the relationship between Chief Executive Officer (CEO) and Chairperson characteristics and firm performance. Specifically, the study examines the association between the characteristics of the CEO and the Chairperson of the board and firm performance. Using a sample of S&P 500 firms, the evidence found suggests that demographic and experience-related characteristics may be associated with the market valuation and financial performance of the firm. In particular, the reported results indicate a positive relationship between the presence of female CEOs or Chairs and firm performance, thus suggesting that gender-based differences may affect the CEO’s/Chairperson’s success. Moreover, the findings concerning the age of the CEO or Chair are mixed, while their experience and quality appear positively related to firm performance. Interestingly, a CEO or Chairperson holding multiple board seats is negatively associated with firm performance, whereas CEO duality has a positive relationship with Tobin’s Q and the return on assets (ROA) of the firm.     

E-governance and Corruption-developments and Issues in Ethiopia

This paper reports the results of a survey of 400 respondents in Ethiopia about factors generating corruption and the potential of e-Governance to mitigate corruption. It is suggested that e-Governance can help not only in weeding out corruption but also in the establishment of sounder government citizen relationships in Ethiopia. While e-Governance cannot cure all the structural factors that breed corruption in the society, strategic implementation of e-Governance can help improve the critical variable in combating corruption-government citizen relationships. It is argued that while e-Governance initiatives can make important contributions to improving public services they can best do so by helping improve overall relationships between governments and citizens.

Career orientations and career success among research,and development and engineering professionals

Managing the careers of research, development and engineering (RD&E) professionals is important to the strategic use of RD&E in the economy. Appropriate mechanisms for motivating RD&E professionals will probably emerge as a critical success factor for organizations that want to compete in world markets. This study examines dimensions and levels of career orientation and their correlations with individual and work-related outcome variables among 78 RD&E professionals. The findings reveal a rich diversity of career orientation in RD&E professionals. The data strongly suggest that RD&E professionals are service, lifestyle and security oriented. However, they scored low on technical orientation and entrepreneurship. This paper suggests that the dual career ladder is not an effective device for managing RD&E professionals. Organizations must be careful to provide career paths that retain and motivate workers and, more importantly, find matches between organizational needs and individuals' needs, and restructure jobs accordingly. The authors offer suggestions for future research and identify implications for management.     

David and Goliath: causes and effects of coopetition between start-ups and corporates

Coopetition (collaboration between competitors) among young firms (i.e. start-ups) and larger, more established firms (i.e. corporates) may be beneficial for both partners as each party typically has something to offer that is missing in the other. Start-ups often develop innovative ideas, are flexible and agile, willing to take risks, and aspire to achieve high growth, but they tend to lack the required resources, capabilities, and knowledge due to their newness and smallness. Corporates have resources, routines, and experience that enable them to work efficiently but lack a certain innovation capability. Research has suggested that coopetition represents an opportunity for start-ups facing restrictions in resources, while corporates benefit from start-ups’ innovative ideas. However, it is yet unknown whether start-ups and corporates engage in coopetition with each other and, if so, how and why they do this. This study seeks to fill this void by exploring the motives of coopeting start-ups and corporates, how they manage their coopetitive relationship, and what implications occur including potential benefits and risks. We present a multiple case study based on qualitative data collected through 70 interviews with Austrian-based start-ups and corporates representing 35 coopetitive partnerships. Discussing the findings based on our data, we propose relationships concerning coopetition and its role to enlarge resource- and technology-bases as well as its role in the development of dynamic capabilities.     

Chronic stress and chronic disease in life and work: Conceptual and methodological issues

This paper argues that the lack of strong prospective evidence linking occupational and social stress to chronic disease stems from the failure of research designs to attend sufficiently to the aetiological chronicity of such diseases. Studies of both supposedly acute stress (life events) and chronic stress in life or work must increasingly be designed to distinguish between stress which is sustained or chronic over a period of yean or even decades, and hence capable of causing a serious chronic disease, and brief or transient stress, which may produce transient or brief psychological or physiological disturbances but cannot generate major chronic disease. Prospective studies are needed which collect measures of both stress and health or disease at multiple points over an extended period of time. Measures of stress should focus more on affect (for example, feelings of pressure and tension) than on cognition (for example feelings of satisfaction). Limited existing evidence is consistent with these ideals.