Principles for Conduct of Pest Risk Analyses: Report of an Expert Workshop

The North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) have focused attention on risk assessment of potential insect, weed, and animal pests and diseases of livestock. These risks have traditionally been addressed through quarantine protocols ranging from limits on the geographical areas from which a product may originate, postharvest disinfestation procedures like fumigation, and inspections at points of export and import, to outright bans. To ensure that plant and animal protection measures are not used as nontariff trade barriers, GATT and NAFTA require pest risk analysis (PRA) to support quarantine decisions. The increased emphasis on PRA has spurred multiple efforts at the national and international level to design frameworks for the conduct of these analyses. As approaches to pest risk analysis proliferate, and the importance of the analyses grows, concerns have arisen about the scientific and technical conduct of pest risk analysis. In January of 1997, the Harvard Center for Risk Analysis (HCRA) held an invitation-only workshop in Washington, D.C. to bring experts in risk analysis and pest characterization together to develop general principles for pest risk analysis. Workshop participants examined current frameworks for PRA, discussed strengths and weaknesses of the approaches, and formulated principles, based on years of experience with risk analysis in other setting and knowledge of the issues specific to analysis of pests. The principles developed highlight the both the similarities of pest risk analysis to other forms of risk analysis, and its unique attributes.     

Models and algorithms for the design of survivable multicommodity flow networks with general failure scenarios

We consider the design of a multicommodity flow network, in which point-to-point demands are routed across the network subject to link capacity restrictions. Such a design must build enough capacity and diverse routing paths through the network to ensure that feasible multicommodity flows continue to exist, even when components of the network fail. In this paper, we examine several methodologies to optimally design a minimum-cost survivable network that continues to support a multicommodity flow under any of a given set of failure scenarios, where each failure scenario consists of the simultaneous failure of multiple arcs. We begin by providing a single extensive form mixed-integer programming formulation for this problem, along with a Benders decomposition algorithm as an alternative to the extensive form approach. We next investigate strategies to improve the performance of the algorithm by augmenting the master problem with several valid inequalities such as cover constraints, connectivity constraints, and path constraints. For the smallest instances (eight nodes, 10 origin–destination pairs, and 10 failure scenarios), the Benders implementation consumes only 10% of the time required by the mixed-integer programming formulation, and our best augmentation strategy reduces the solution time by another 50%. For medium- and large-sized instances, the extensive form problem fails to terminate within 2 h on any instance, while our decomposition algorithms provide optimal solutions on all but two problem instances.     

产品回收逆向物流网络优化设计模型

为了在传统正向物流网络基础上扩建产品回收逆向物流网络,基于混合整数线性规划方法建立了一种单产品、有能力限制的产品回收逆向物流网络优化设计模型,据此确定物流网络中各种设施的数量和位置,并在由此构成的各条物流路径上合理分配物流量,以使各种设施的投资和运营成本之和最小。给出了提高模型求解效率的Benders分解算法,并通过算例验证了模型和算法的有效性。     

自由贸易试验区设立能矫正资本错配吗？——兼论产业集聚的调节效应

本研究尝试将自由贸易试验区和产业集聚同时纳入资本配置效率分析框架,将自贸区设立作为一项准自然实验,利用2004-2017年中国196个地级及以上城市面板数据,采用双重差分模型和系统广义矩估计方法,评估自贸区设立对资本错配的影响以及产业集聚的调节效应。研究发现：资本错配在时间维度上存在“路径依赖”现象,自贸区设立在整体上加剧了资本错配。全样本情况下,不同类型的产业集聚在自贸区设立对资本错配的影响中发挥了不同的作用,制造业与生产性服务业协同集聚有助于自贸区发挥对资本错配的矫正作用,而单纯的制造业或生产性服务业集聚则强化了自贸区对资本错配的加剧。区分资本错配类型后发现,在资本配置不足情形下,产业集聚在自贸区影响资本错配过程中的调节效应与全样本情况下一致;而在资本配置过度的情形下,制造业、生产性服务业以及二者的协同集聚均有助于自贸区发挥出对资本错配的矫正作用。围绕上述问题的理论阐释和实证检验,为矫正资本错配,提高资本配置效率、促进自贸区改革创新和实体经济高质量协同发展提供了丰富的政策蕴含。     

Logic-based Benders decomposition for an inventory-location problem with service constraints

We study an integrated inventory-location problem with service requirements faced by an aerospace company in designing its service parts logistics network. Customer demand is Poisson distributed and the service levels are time-based leading to highly non-linear, stochastic service constraints and a nonlinear, mixed-integer optimization problem. Unlike previous work in the literature, which propose approximations for the nonlinear constraints, we present an exact solution methodology using logic-based Benders decomposition. We decompose the problem to separate the location decisions in the master problem from the inventory decisions in the subproblem. We propose a new family of valid cuts and prove that the algorithm is guaranteed to converge to optimality. This is the first attempt to solve this type of problem exactly. Then, we present a new restrict-and-decompose scheme to further decompose the Benders master problem by part. We test on industry instances as well as random instances. Using the exact algorithm and restrict-and-decompose scheme we are able to solve industry instances with up to 60 parts within reasonable time, while the maximum number of parts attempted in the literature is 5.     

The management of firms’ alliance network positioning: Implications for innovation

In spite of the frequent calls for a much more integrated approach, the field of management still faces the ever continuing challenges in attempting to bridge the gap between academic research and managerial actions and practices. The field of strategic alliances and firms’ networks are those among which research and practice are more diverging. Trying to cover this separation, the article presents an empirical research on automotive industry that investigates the effects on innovation performance of the position that firms occupy in the network of alliances. The hypothesis that guides this research is that innovation is generated not only from the resources that a company is able to develop internally, but also through access to resources and capabilities owned by the external companies and organizations that the firm itself is tied to through alliances and cooperation agreements. Beyond this broad argument, the paper links tightly research and practice showing way and how the quality of access to resources owned by partners is influenced by the position occupied in the network of alliances and not only by the existence of single collaborative ties. Assuming a managerial approach which relies on the milestones of network research, different types of positioning in the network of alliances are discussed and tested on their impact on innovation.     

Proactive international strategies of cluster SMEs

In this conceptual paper, proactive international strategies of small- and medium-sized enterprises (SMEs) in the cluster context are discussed. The majority of cluster SMEs assume passive roles as network participants in the process of internationalisation. However, a smaller fraction adopts proactive strategies to foreign expansion acting as leaders of networks. SMEs as network leaders are embedded in the source clusters and dependent on local networks that provide them with complementary resources. We assert that this mutual dependence between a firm's resources and the development of industrial agglomeration should be reflected in the strategic options that SMEs adopt when going international. This paper contributes by synthesising and evaluating a comprehensive range of SME-strategic options and by proposing the proactive competitive strategies of SMEs in the international arena that are both feasible and effective. The feasibility of adopting a specific strategy means the suitability for this group of companies, considering their characteristics. The evaluation of the effectiveness of each strategy was performed according to the objectives of avoiding lock-in and of protecting and developing the core competencies embedded in cluster networks. We address the research gap in evaluating the outcomes of SME international strategies and in synthesising a comprehensive range of cluster SMEs' strategic options.     

THE IMPACT OF LOCAL CONTENT RULES ON GLOBAL SOURCING DECISIONS

Many governments have established, for various reasons, local confent purchasing rules for companies that wish to operate in their country. These requirements force firms to purchase a certain amount of components from suppliers located in that country. This paper describes local content rules and develops models to select suppliers while satisfying local content provisions. The single plant model can be transformed into a knapsack problem that is solved by a ranking procedure, and the solution provides insight as to the manner in which local content rules impact more generalized models. Furthermore, we illustrate possible negative effects to local industry that may result when governments set the local content percentage too high, and we discuss methods for companies to circumvent local content rules. Finally, we address the issue of local content rules in the context of multi-plant global sourcing decisions, and we provide an efficient solution procedure for the classical plant location model extended to include local content rules at each site     

Supply Chain Management: Relationships, Chains and Networks

The term supply chain management is used to represent a variety of different meanings, some related to management processes, others to structural organization of businesses. This paper identifies and discusses various definitions of supply chain management, summarizes the associated bodies of knowledge and connects them using a systems approach. Systems levels of supply chain management are identified as the internal supply chain, the dyadic relationship, the external supply chain and the inter-business network.
Empirical research on behavioural aspects of relationships, chains and networks in the European automotive aftermarket is discussed, identifying gaps in perceptions of requirements and performance held by customers and suppliers in the areas of quality, delivery, service, range and price. A combination of qualitative and quantitative analysis demonstrates substantial differences between approaches to supply chain management, though performance in relationships, chains and networks in the territories examined does not differ significantly.
Customer dissatisfaction in relationships is shown to increase upstream in the supply chains examined, extending the applicability of the industrial dynamics 'Forrester effect' to softer, behavioural aspects of performance. Conclusions are drawn supporting the suggestions of operations strategists that position in the supply chain is an important strategic variable which, to date, have not been comprehensively proven empirically.     

中国保税区发展水平的集成式智能型综合评价系统研究

本文以决策支持系统的理论方法为基础,综合运用人工智能、专家系统、模糊集、因子分析等理论方法,提出了中国保税区发展水平综合评价的指标体系,介绍了中国保税区发展水平的集成式智能化综合评价系统(IICES)的基本结构模式,探讨了IICES的实现技术与方法,给出了IICES的应用实例。     

考虑顾客策略行为的易逝品定价与再制造柔性补货机制研究

本文将再制造作为一种柔性补货机制,研究了考虑顾客策略行为的易逝品定价和再制造柔性补货问题。研究表明顾客策略行为减少了零售商的期望利润,再制造柔性补货机制可以缓解顾客策略行为的影响,提高零售商的期望利润,最后分析了该机制对消费者剩余和社会福利的影响。     

考虑顾客策略行为和产品质量的闭环供应链决策模型

策略型的顾客对于不同质量的产品以及不同时间的产品会有不同的估值和支付意愿,企业在进行决策时应当考虑顾客的策略性行为。建立了由一个制造商(即原始设备制造商)和一个独立的再制造商以及一组策略型顾客组成的闭环供应链模型,利用动态博弈理论分析了当由独立的再制造商负责回收旧产品并进行再制造时顾客策略行为和再制造品的质量水平对闭环供应链的产品价格、利润、消费者剩余的影响。研究结果表明,当顾客的策略程度增加时,制造商的利润减少,再制造商的利润和消费者剩余增加。当再制造品的质量水平增加时,制造商的利润降低,再制造商的利润先增加后降低,消费者剩余增加。     

How Japanese partners help US manufacturers to raise productivity

Cross-border alliances are useful strategies for technological innovation and as a basis for the adaptation of foreign technologies. This study provides evidence that through strategic alliances US automotive firms are effectively adopting manufacturing technologies from Japan, and are adapting them to the US industrial context.

The results show that US firms without foreign affiliations use fewer modern manufacturing technologies than US firms with Japanese strategic alliance partners. Furthermore, US firms with Japanese strategic alliance partners believe that manufacturing cycle times for product introduction are more efficient that US firms without foreign affiliations.     

Dynamic interdiction networks with applications in illicit supply chains

We study the interdiction of illegal product distribution in a network with multiple sources (origins) and sinks (destinations). This work contributes to the literature of dynamic maximum flow interdiction problems by addressing multiple commodities in a network of relationships. The related distribution network consists of (1) criminals, who are hierarchically connected, and seeking to maximize the total profit flow from origins to destinations, and (2) enforcement officers aiming to minimize criminals’ long-term success by monitoring and arresting them, using the limited resources at their disposal. Considering several real-world operational details, we first propose a mixed-integer programming model by reformulating a Min–Max bi-level mathematical model. We then propose a new formulation and discuss its efficiency compared with the traditional duality-based reformulation. This new formulation also has a higher compatibility with decomposition solution methods. Utilizing the new formulation, we design a solution method based on the Benders decomposition procedure and apply several accelerating strategies (e.g., Super Valid Inequalities) to solve larger instances for a better representation of reality. Lastly, we create a heuristic method based on real-world evidence, which is usually practiced by law enforcement officers. Our results show that the quality of the heuristic method declines quickly as the network size increases.     

A Hierarchical Product Development Planning Framework

Uncertainty in new product development (NPD) planning embraces market, creative, technological, and process dimensions to a much greater extent than in non‐NPD project planning. Yet, NPD management is becoming increasingly decentralized, both within the firm and across the supply chain. Hence, planning for NPD uncertainty often results in path‐dependent scenarios cutting across the strategic, tactical, and operational levels of planning. To coordinate this resulting complexity, we propose a stochastic hierarchical product development planning framework with multiple recourses, i. e., corrective actions, to maximize performance across a firm's entire NPD program. We also argue the necessity for a fourth planning level, the infrastructural, that reestablishes norms for market projections, technological forecasts, scheduling, and requirements as latent uncertainty in the environment is continually revealed. An illustration from the automotive industry is presented to demonstrate a deployment of our framework. We additionally discuss the applicability of this framework for managing NPD capabilities over time.     

Fair Trade Awareness and Engagement: A Coffee Farmer's Perspective

As one of the world's most traded commodities, coffee has been criticized for its contribution to environmental degradation, social injustice, and economic disparities between the producing regions of the Global South and consuming countries of the Global North. However, the Fair Trade concept is promising to change this through the establishment of a trading system where producers, importers, and processors form a more direct network characterized by an established set of ethical principles and practices deemed as “fair.” While the transformational benefits of Fair Trade at the producer level have been examined in several impact studies, the farmers' low awareness and understanding of Fair Trade concepts, principles, markets, and customers represent an issue of concern. Among the many benefits associated with increased Fair Trade awareness is greater participation in Fair Trade governance bodies and the long‐term viability of the market itself. This research looks at Fair Trade from the perspective of farmers and their cooperative and uses the case of Cooperativa Agraria Cafetalera Pangoa, Peru, to examine how Fair Trade awareness (defined as knowledge of different areas of Fair Trade) is understood at the producer level. We then develop a three‐level Fair Trade awareness Model that illustrates both the existing and desired levels of understanding with regard to Fair Trade awareness.     

基于在线评论和随机占优准则的生鲜电商顾客满意度测评

生鲜电商被认为是电子商务领域的下一片蓝海，吸引着各类资本、平台竞相追逐，但目前生鲜电商仍处于发展探索阶段，如何及时准确地把握顾客需求和有效地提升顾客满意度是当前面临的重要问题。本文提出一种基于在线评论和随机占优准则的生鲜电商顾客满意度测评方法：首先，利用生鲜电商存在的大量在线评论数据信息，基于LDA模型提取出在线评论中的主题，作为顾客对生鲜电商满意度的影响因素；其次，构建生鲜电商顾客需求的情感词典，计算在线评论中顾客的情感倾向得分，作为判断顾客满意度的依据；最后，利用随机占优准则，构建不同商品类别中影响因素的随机占优程度矩阵，并应用PROMETHEE-Ⅱ方法给出不同商品类别中影响因素的排序结果。通过爬取天猫网站中不同类别的生鲜商品在线评论信息进行顾客满意度评估的案例分析，验证本文提出的方法的可行性和有效性。结果显示，不同生鲜商品类别中顾客满意度影响因素的重要度排序是不同的。值得注意的是，所提方法也为其他产品或服务的顾客满意度评估问题提供了参考和支撑。     

Decomposition algorithms for the integrated process planning and scheduling problem

There are several algorithms to solve the integrated process planning and scheduling (IPPS) problem (i.e., flexible job shop scheduling with process plan flexibility) in the literature. All the existing algorithms for IPPS are heuristic-based search methods and no research has investigated the use of exact solution methods for this problem. We develop several decomposition approaches based on the logic-based Benders decomposition (LBBD) algorithm. Our LBBD algorithm allows us to partition the decision variables in the IPPS problem into two models, master-problem and sub-problem. The master-problem determines process plan and operation-machine assignment, while the sub-problem optimizes sequencing and scheduling decisions. To achieve faster convergence, we develop two relaxations for the optimal makespan objective function and incorporate them into the master-problem. We analyze the performance and further enhance the algorithm with two ideas, a Benders optimality cut based on the critical path and a faster heuristic way to solve the sub-problem. 16 standard benchmark instances available in the literature are solved to evaluate and compare the performances of our algorithms with those of the state-of-the-art methods in the literature. The proposed algorithm either results in the optimal solution or improves the best-known solutions in all the existing instances, demonstrating its superiority to the existing state-of-the-art methods in literature.     

考虑地区间环保投入策略互动的高质量发展研究

在考虑地区环保投入具有策略互动特征的基础上,模型分析了禀赋和财政能力差异对地方政府政策目标的影响,并讨论了平衡地区资源禀赋的生态转移支付政策对地区间环保联合产出水平的影响。研究结果表明：地区间环保投入策略互动特征的引入,使得环保联合产出最大化对应于适度的地方政府资源禀赋差异程度,差异程度过大或者过于平均,都不利于激发地方政府活力,为高质量的经济持续发展提供稳定条件。此外,专项转移支付政策相比于总量转移支付政策,能够更有效地激励地方政府在生态环境方面投入努力;而减少专项转移支付在实践中的信息对称要求,建立市场化运作资金池的横向转移支付制度安排是进一步加大地区环保投入水平的可行政策。从协调地区经济发展差异、确保环保投入发挥成效,测度地区生态外溢效应、优化专项转移支付政策,建立市场化运作资金池、提升横向转移支付占比等方面,提出提升我国环保投入资金使用效率的对策建议。