Median problems with positive and negative weights on cycles and cacti

This paper deals with facility location problems on graphs with positive and negative vertex weights. We consider two different objective functions: In the first one (MWD) vertices with positive weight are assigned to the closest facility, whereas vertices with negative weight are assigned to the farthest facility. In the second one (WMD) all the vertices are assigned to the nearest facility. For the MWD model it is shown that there exists a finite set of points in the graph which contains the locations of facilities in an optimal solution. Furthermore, algorithms for both models for the 2-median problem on a cycle are developed. The algorithm for the MWD model runs in linear time, whereas the algorithm for the WMD model has a time complexity of  O(n²)\mathcal{O}(n^{2}) .     

Federalism and the Implementation of Environmental Policy: Changing Trends in Canada and the United States

In a federal system of government, powers are shared by the national and sub-national units in accordance with the provisions of the Constitution. However, the process of policy implementation may differ on the basis of allocation of power and the nature of the system. Canada and the United States of America adopted federal systems of government, and faced similar pressures for implementing policies on environmental issues. Yet, the degree of success and outcome appear to be different due to variations in the strength of the respective federalist systems. An analysis of the various aspects of the federal system in the two countries reveals noticeable differences in institutional configurations, relationship between national and sub-national units, and variances in intra-institutional relations. All these have contributed to a divergence in the past, but there is an emerging trend of convergence as both the Canadian and American governments are gradually moving away from their existing patterns of policy implementation toward a new approach involving private-sector initiatives and self-enforcement with strong inclinations toward voluntarization, corporatization and marketization.     

The impact of institutional changes on corporate governance mechanisms in transition economies

We examine how institutional changes affect corporate governance in transition economies. We develop a transition model that specifies three stages of the transition process including the early, intermediate, and late. We develop a framework for assessing the effectiveness of widely recognized corporate governance mechanisms (CGMs) in and across these stages. Our general proposition is that as transition economies move from early, to intermediate, to late stages, effective CGMs tend to be those that are based on state administrative control power, social networks and private orders, and market forces and formal institutions, respectively. Our study has contributions and implications regarding the transition economies and the impacts of institutions on corporate governance.     

Assessment of Catastrophic Risk Using Bayesian Network Constructed from Domain Knowledge and Spatial Data

Prediction of natural disasters and their consequences is difficult due to the uncertainties and complexity of multiple related factors. This article explores the use of domain knowledge and spatial data to construct a Bayesian network (BN) that facilitates the integration of multiple factors and quantification of uncertainties within a consistent system for assessment of catastrophic risk. A BN is chosen due to its advantages such as merging multiple source data and domain knowledge in a consistent system, learning from the data set, inference with missing data, and support of decision making. A key advantage of our methodology is the combination of domain knowledge and learning from the data to construct a robust network. To improve the assessment, we employ spatial data analysis and data mining to extend the training data set, select risk factors, and fine‐tune the network. Another major advantage of our methodology is the integration of an optimal discretizer, informative feature selector, learners, search strategies for local topologies, and Bayesian model averaging. These techniques all contribute to a robust prediction of risk probability of natural disasters. In the flood disaster's study, our methodology achieved a better probability of detection of high risk, a better precision, and a better ROC area compared with other methods, using both cross‐validation and prediction of catastrophic risk based on historic data. Our results suggest that BN is a good alternative for risk assessment and as a decision tool in the management of catastrophic risk.     

Beyond Technical Competence: The Loyalty Factor

This study discusses an attribute of leadership that is beyond technicalcompetence. Defines `Loyalty' as an unwavering commitment to colleagues,organizations, and to oneself. Clarifies the development of a loyalty and theformation of operational principles are synergetic for ethical behavior.Explains `Loyalty' and the manner in which it differs from unethical, illegal,or immoral behavior. Depicts `loyalty' as an essential behavior that promotesand supports quality leadership. Provides guidance, techniques, and examplesthat can be used to enhance leadership skills. Establishes a sound philosophyto increase the probability for long-term success and professionalfulfillment. Includes quotes from contemporary as well as historical leaders.     

Higher Education's Role in the Dialogue on Race

The university is a logical locus for discussionof the role race has played in our society. Perhaps noAmerican institution is more committed to free andopen dialogue than the university. Higher educationcan thus provide a context for the recognition ofissues as well as a forum for the resolution ofinitiatives. To date, however, university attempts atdiversity training have often imbued recipients withself-consciousness, usurping the unity implicit in theword `university' and evoking an even greater tendencytoward separatism. The university's traditional questfor truth has been subverted by a subtle and pervasivesense that some views are more correct than others,that openness is dangerous, and that some issues mighteven be taboo. At best, such an approach to diversityleads to a fragile stalemate among self-containedenclaves. By championing President Clinton's call fora dialogue on race, the university can restore itselfas an institution that puts honesty above all else.Not only is there a resonant rationale for theuniversity's central responsibility in this debate,but there is also a pedagogical means by which itsrole can be realized. This paper proposes a model forethnic dialogue relevant to either a text-based orissues-based class. Borrowing from pedagogy developedin professional schools, we believe that the tenets ofthe `case method' can create a climate conducive tothe substantive scrutiny of race, ethnicity, andprejudice in general. We argue that this dialogueshould not be a mere add-on to college life, butintegrated into existing curricula in the socialsciences, literature, and history. Heated debate canthen occur without anger, and race/ethnicity can bediscussed without fear of recrimination.Paradoxically, the very expression of ethnicity may bethe catalyst that eventually moves multiculturalismtoward interculturalism – where differences are nolonger articulated, measurable or even discernible.     

网络环境下服务科学与创新管理研究展望

基于网络环境的服务发展与创新已成为经济发展的新引擎。本文在分析网络环境下服务特征基础上,探讨了其对服务科学与创新管理研究的影响。结合我国社会经济发展对现代服务快速增长的需求,本文提炼了服务科学研究的三类基本科学问题,包括服务价值的内涵与度量,服务资源的要素及其价值生成,和服务关系的界定与形成问题;提出了服务与创新管理的四个重要研究领域,即：服务生态系统的形成与演化,服务资源要素的组织与协调,服务的关联与融合和社会服务运作管理问题。在四个重要研究领域的进一步分析中,论文以一个异质数据服务资源的组织与融合为例,描述了服务资源组织与协调的一个具体问题,说明了已有研究方法解决该问题的困难,和未来该问题研究需要关注的重点;另以平台服务中基于价值和关系的服务定价问题为例,说明服务关联与融合研究的挑战及其未来研究的努力方向。     

异质品双渠道供应链下制造商的渠道决策研究

研究由两个制造商、两个零售商以及消费者组成的双渠道供应链,制造商的最优产品分销渠道策略问题,通过构建Stackelberg主从动态博弈模型,分析制造商在不同渠道选择下的产品质量水平及定价决策,消费者三种不同渠道偏好下渠道竞争和品牌竞争激烈程度对制造商渠道选择均衡结果及帕累托最优选择的影响,以及对产品质量水平、产品价格、制造商及零售商利润的影响.研究表明：品牌和渠道双重竞争下,两种竞争之间存在相互作用的关系,并共同影响制造商最终渠道选择,制造商通过权衡价格决策的后动优势与消费者渠道偏好对其利润的贡献选择是否开辟双渠道,产品价格与产品质量水平正相关,与产品的替代率负相关,产品质量水平对渠道价格的影响程度等于消费者对该渠道的偏好程度.当消费者偏好某一渠道时,制造商可在该渠道上的产品采取优质高价策略,但渠道上产品性价比降低,当品牌竞争越激烈,产品价格越低,对制造商和零售商的利润挤压越严重.     

On tree representations of relations and graphs: symbolic ultrametrics and cograph edge decompositions

Tree representations of (sets of) symmetric binary relations, or equivalently edge-colored undirected graphs, are of central interest, e.g. in phylogenomics. In this context symbolic ultrametrics play a crucial role. Symbolic ultrametrics define an edge-colored complete graph that allows to represent the topology of this graph as a vertex-colored tree. Here, we are interested in the structure and the complexity of certain combinatorial problems resulting from considerations based on symbolic ultrametrics, and on algorithms to solve them.This includes, the characterization of symbolic ultrametrics that additionally distinguishes between edges and non-edges of arbitrary edge-colored graphs G and thus, yielding a tree representation of G, by means of so-called cographs. Moreover, we address the problem of finding “closest” symbolic ultrametrics and show the NP-completeness of the three problems: symbolic ultrametric editing, completion and deletion. Finally, as not all graphs are cographs, and hence, do not have a tree representation, we ask, furthermore, what is the minimum number of cotrees needed to represent the topology of an arbitrary non-cograph G. This is equivalent to find an optimal cograph edge k-decomposition \(\{E_1,\dots ,E_k\}\) of E so that each subgraph \((V,E_i)\) of G is a cograph. We investigate this problem in full detail, resulting in several new open problems, and NP-hardness results.For all optimization problems proven to be NP-hard we will provide integer linear program formulations to solve them.