Performance evaluation of two-worker operations in a worker-to-cell order assorting system

This paper studies an order assorting system (OAS) composed of multiple-parallel order assorting aisles (OAAs) in a retailer’s order fulfillment center. We evaluate two worker-assignment policies for a worker-to-part OAA: a dedicated-assignment policy and a shared-assignment policy. Our analytical models evaluate the mean value and variance of worker process time including assorting time, walk time, empty walk time, and blocking time when single-line products arrive randomly. From the worker process time, we identify the system flow time of product lines per each worker-assignment policy using G/G/1 and G/G/2 queuing models. We find that the shared-assignment policy performs better compared to the dedicated-assignment policy in spite of workers’ productivity losses incurred by blocking delays over high sort probability, slow walk speed, and high magnitude and variations of inter-arrival times. At the worker-centric break-even point of worker process time, where worker process time suggests selecting either policy, system flow time always suggests selecting the shared-assignment policy.     

Peeking at the ERP Decline stage: Japanese empirical evidence

This research located and analyzed forty case studies in Japan related to Enterprise Resource Planning (ERP) switching, and specifically discussed the Decline stage of the ERP Life Cycle which has not been concerned enough in the academia. Qualitative data was mainly collected to answer the research questions fully. The results indicate the Decline stage does exist empirically. The prior studies explore the ERP failure cases which usually happen soon after the kickoff. This research finds empirical evident that both Large Enterprises (LEs) and Small and Medium Enterprises (SMEs) have experienced some kinds of declining in system performance and business performance, and had the urges and needs to retire or upgrade the current ERP system. Based on the findings, the causes of ERP termination, the two strategies which organizations adopted to deal with the current ERP systems, and the five events after the decision-making point were summarized and discussed. The findings also revealed three ambiguous issues that need more efforts. The results of this research fill up the blank in the ERP life cycle theory for more than one decade. The findings from a relatively large sample can also help practitioners and researchers to explore the shifting period more thoroughly and to build tools to solve current and potential problems in order to prepare and assist organizations.     

Making connections and building bridges: improving the bi-national planning process

Creating a continental transportation system that supports the efficient movement of goods between Canada and the United States is essential to the economies of both countries. However, 25 years after the passage of the Canada–US Free Trade Act and many agreements and accords later, poor connectivity, congestion and delays still plague many transborder corridors. Recent attempts to improve this situation involving several proposed new bridge projects have either been halted or significantly delayed over the last decade. This paper will review and critically examine the bi-national planning process that has been followed in an attempt to build a new bridge across the Detroit River, known as the Detroit River International Crossing (DRIC) project.     

Sustainable energy planning decision using the intuitionistic fuzzy analytic hierarchy process: choosing energy technology in Malaysia

Energy consumption for developing countries is sharply increasing due to the higher economic growth due to industrialisation along with population growth and urbanisation. The increasing demand of energy leads to global energy crisis. Selecting the best energy technology and conservation requires both quantitative and qualitative evaluation criteria. The fuzzy set-based approach is one of the well-known theories to handle fuzziness, uncertainty in decision-making and vagueness of information. This paper proposes a new method of intuitionistic fuzzy analytic hierarchy process (IF-AHP) to deal with the uncertainty in decision-making. The new IF-AHP is applied to establish a preference in the sustainable energy planning decision-making problem. Three decision-makers attached with Malaysian government agencies were interviewed to provide linguistic judgement prior to analysing with the new IF-AHP. Nuclear energy has been decided as the best alternative in energy planning which provides the highest weight among all the seven alternatives.     

Greenfield distribution network expansion strategy with hierarchical GA and MCDEA under uncertainty

Distribution network expansion planning (DNEP) is becoming more complex in nature. Addition of new load centers, due to increasing conversion of greenfield areas into habitats, have generated need of more intense and highly structured planning strategies. Micro level work on distribution expansion planning has been ignored by most of the researchers mainly in Indian scenario. Since practical distribution networks are quite large, number of candidates (load centers) will be more and, hence, number of variables (electrical parameters and new load center feasible connections with the existing system) are remarkable. Optimizing a large system may result in significant decrease of accuracy and increase of computation time. For deciphering this issue, segmentation procedure has been applicable. For this purpose, a sensitivity analysis has been applied to find dependent variables. It is obvious that a correct segmentation can decrease computation time (as a single task is operated in segments simultaneously) while accuracy decreases negligibly. In present work, a scheme has been introduced to connect three greenfield load centers with existing primary distribution system by using hierarchical genetic algorithm (HGA). HGA is an integrated approach of analytical hierarchical process and genetic algorithm. The paper reports best selection of investment with finest voltage profile and least losses while maintaining radiality of the system. DNEP has been done at micro level and proposed methodology has been tested on a small dimension practical distribution system. The novelty of this paper is to optimize the best possible selection of connection of new load centers with existing system with the help of AHP and GA and results have been verified with advance optimal tool multiple criteria data envelopment analysis (MCDEA). HGA and MCDEA are applied to practical nine bus distribution system and the results are presented and compared.     

Rolling Kanban: a new visual tool to schedule family batch manufacturing processes with kanban

Rolling Kanban is the name of a kanban management methodology for batch processes manufacturing environment. Proposed in the early 2000s by FESTO Consulting, for two decades we have lost knowledge both from operative and scientific point of view. Basically, Rolling Kanban means a visual planning methodology based on the production of product-families and variants where: (i) set-up times are reduced between the products of the same family, and (ii) relevant times (dozens of minutes if not even hours) must be considered for changeover between products of different families. In addition, the cyclic production sequence between different product families cannot be maintained. Considering that very few technical information and documents are available about this approach, the main objective of this paper is to retrieve and present, for the first time to the scientific community, the Rolling Kanban methodology. Besides, a real industrial implementation concerning a manufacturer of domestic fittings is discussed as a case study. More specifically, two novel versions of the original Rolling Kanban technique are fully presented to effectively overcome certain limits and criticalities found during its operative use, such as the difficulty to realise a pull production, considering increased set-up time for changeover between products of different families.     

新中国早期产品品牌命名和设计范式探究——以烟标为例

新中国早期产品品牌的命名和设计,在政治内容、审美趣味与商业企图之间获得了平衡。构建了易于被大众接受,群众喜闻乐见,紧随时代潮流的命名和设计范式。其中,以烟标最为典型,散发出鲜明的视觉特色和独有魅力,给人们留下诸多的回忆。为新中国立国建国、经济建设、航天国防、友好和平和文化生活等方面信息的传播和价值观的塑造,作出了不可忽视的贡献,也为现代产品品牌的命名和设计提供了早期的范式参考。     

新型树启发式搜索算法的机器人路径规划

面对三维空间移动机器人从起始点到终止点的最短路径问题,提出一种新型的边缘点树启发式搜索(TreeEP)算法,该方法将地图空间进行密度可调的三维离散化处理,根据障碍安全距离筛选出障碍物的可靠边缘点信息,再利用树扩散架构选出最能引导搜索方向的潜力点进行扩散搜索,最终得出最短路径。提出局部调整策略,得到改进的Tree-EP算法。实验结果表明,在带障碍复杂地形最短路径搜索应用中,提出的Tree-EP算法与已有方法相比,能找到更短的移动路径。     

交互与新生——武汉大学早期校园规划思想解读

武汉大学早期校园具有较高的历史、科学、艺术和文化价值,是我国近代大学校园规划和设计的典范,然而关于其校园规划思想的研究却比较匮乏。本文根据设计师开尔斯和莱文斯比尔的设计手稿以及多种关于校园建设的原始文字档案,从时代背景、建校理念用地环境三个方面分析影响早期校园规划和建筑形制形成的因素。旨在全球视阈下解读武汉大学早期校园规划思想,凸显出武汉大学校园规划及建设的全球关联性。     

Lagrangean relaxation approach to joint optimization for production planning and scheduling of synchronous assembly lines

This paper focuses on simultaneous optimisation of production planning and scheduling problem over a time period for synchronous assembly lines. Differing from traditional top-down approaches, a mixed integer programming model which jointly considers production planning and detailed scheduling constraints is formulated, and a Lagrangian relaxation method is developed for the proposed model, whereby the integrated problem is decomposed into planning, batch sequencing, tardiness and earliness sub-problems. The scheduling sub-problem is modelled as a time-dependent travelling salesman problem, which is solved using a dynasearch algorithm. A proposition of Lagrangian multipliers is established to accelerate the convergence speed of the proposed algorithm. The average direction strategy is employed to solve the Lagrangian dual problem. Test results demonstrate that the proposed model and algorithm are effective and efficient.