Optimal locations and flow allocations for aggregation hubs in supply chain networks of perishable products

Establishment of aggregation hubs in a supply chain network (SCN) is typically a facility location-allocation (FLA) decision, which is known to be a NP-hard optimization problem. Considering the flow of heterogeneous perishable products, like fresh produce, with different spoilage rates, further increases the complexity of such a problem. This is due to the effect of transportation time and conditions, services provided in the hub, and hub proximity to supply sources, on the quality and quantity of products eventually reaching the demand destinations, and hence on the location-allocation decision. In this paper, this problem is formulated as a mixed integer linear programming (MILP) model that considers a number of problem characteristics simultaneously for the first time, to minimize the transportation, spoilage, processing, and capacity-based hub establishment costs. Due to its complexity, two hybrid algorithms that combine a meta-heuristic with a perishability-modified transportation algorithm, are proposed to solve the problem. The algorithms are based on binary particle swarm optimization (BPSO) and simulated annealing (SA). Taguchi analysis is used to tune the significant parameters of both algorithms considering different problem sizes. Computational analysis is further conducted to evaluate and compare the performances of the algorithms using randomly generated test instances and exact solutions obtained using CPLEX. Results show that while both algorithms are capable of obtaining optimum solutions for most instances, the hybrid BPSO slightly outperforms the hybrid SA in terms of consistency and solution time.     

Location-allocation problem for intra-transportation system in a big company by using meta-heuristic algorithm

This paper presents the location-allocation problem of parking facilities in Mobarakeh Steel Company. The aim is to find the optimal location for the parking facilities and allocate travels between departments to each parking facility. To optimize the cost and facing the transportation demands of all departments, a mathematical model is designed and solved by a commercial software package. Also, the number of vehicles allocated to each parking facility is determined. A hybrid meta-heuristic algorithm combining a genetic algorithm with parallel simulated annealing is developed which can be used even in more complicated structure of the problem. The results show that this hybrid algorithm is highly efficient in solving this kind of problems.     

Planning for equal transit-based accessibility of healthcare facilities: A case study of Shenzhen,China

Recent location-allocation studies have made considerable progress in optimizing the equality of facility accessibility but are focused on automobile transport to facilities. In cities, however, the transit-based accessibility of essential services is crucial for social equality and sustainable development. In this study, we develop a modified transit-based maximal accessibility equality (MAE) model for optimizing the equality of the transit-based accessibility of healthcare facilities. In this model, equality is quantified as the weighted mean absolute deviation (WMAD) of accessibility across locations. Two scenarios are set up to reallocate resources or allocate newly added resources. The results reveal that the equality of transit-based healthcare accessibility can be significantly improved in both scenarios. A dispersed planning strategy for facilities is suggested to achieve equal accessibility. However, the transit-based optimization results significantly differ from the car-based optimization results, with more supply allocated to facilities close to transit corridors. This finding implies that the traditional car-based MAE model might generate unequal healthcare accessibility for transit-dependent populations and thus lead to biased recommendations for healthcare planning. Furthermore, it shows that traditional car-based optimization may engender a misallocation of healthcare supply, exacerbating the inequality in healthcare accessibility. The necessity of incorporating public transit into public facility planning is highlighted. The improved MAE model can be applied in cities where the supply of public services is relatively adequate and public transit plays an important role in daily mobility.     

Selection of enterprise resource planning software using analytic hierarchy process

Selecting ERP (Enterprise Resource Planning) software is crucial to enhance productivity because it provides high-quality services for end users. The choice of an ERP is a problem that should undertake deeper scrutiny. For example, several criteria are usually present, having different tradeoffs. Analysts and managers, when deciding which ERP to acquire, have key considerations to address when facing the myriad of available software suites with market presence. Multicriteria modelling are used to help decision makers select ERPs and one commonly used technique for helping the process of addressing such problems is Analytic Hierarchy Process (AHP). Our work have surveyed the literature on selection of ERP and we have discovered that acquisition and monthly costs, ERP reputation and references, level of support and training, deployment experience, ERP’s feature set, easiness of use, efficiency and reliability, and maintainability are key criteria. We have used those criteria to create an AHP model for deciding the best one according to judgements of importance. The focus of our work is directed for small and medium organizations. We have created a model for ERP selection of a healthcare facility and computed numerical results using pairwise comparisons and group decision-making by selected managers according to their expertise.     

AHP在总承包商选择项目中的应用探析

工程项目特点决定了对承包商面临着很大的风险。采用AHP方法来选择项目，为影响项目的风险因素和可供选择的项目构建了一个层次结构，并提出分析模型和计算方法，通过实例分析，AHP能够优先考虑影响因子，由此得到项目的权重综合排序，从而选择最后的项目。该方法能减少人为因素的影响，增强了决策的客观性和科学性。     

A multiobjective modeling approach to locating incinerators

The location of hazardous material incineration facilities is an important problem due to the environmental, social, and economic impacts that they impose. The costs associated with the facilities and the risks placed on nearby populations are important concerns as are the distributions of these costs and risks. This paper introduces a mixed-integer, multiobjective programming approach to identify the locations and capacities of such facilities. The approach incorporates a Gaussian dispersion model and a multiobjective optimization model in a GIS-based interactive decision support system that planners can access via the Internet. The proposed approach is demonstrated via a case study in central Portugal where the national government has decided to locate a large facility for the incineration of hazardous industrial waste. Due to intense local and national opposition, construction of the facility has been delayed. The system has been designed so that it can be used by decision makers with no special training in dispersion modeling, multiobjective programming, or GIS.     

The flow-refueling location problem for alternative-fuel vehicles

Beginning with Hodgson (Geogr.Anal.22(1990) 270), several researchers have been developing a new kind of location-allocation model for “flow capturing.” Instead of locating central facilities to serve demand at fixed points in space, their models aim to serve demand consisting of origin-destination flows along their shortest paths. This paper extends flow-capturing models to optimal location of refueling facilities for alternative-fuel (alt-fuel) vehicles, such as hydrogen fuel cells or natural gas. Existing flow-capturing models assume that if a flow passes just one facility along its path, it is covered. This assumption does not carry over to vehicle refueling because of the limited range of vehicles. For refueling, it may be necessary to stop at more than one facility in order to successfully refuel the entire path, depending on the vehicle range, the path length, and the node spacing. The Flow Refueling Location Model (FRLM) optimally locates p refueling stations on a network so as to maximize the total flow volume refueled. This paper presents a mixed-integer programming formulation for the nodes-only version of the problem, as well as an algorithm for determining all combinations of nodes that can refuel a given path. A greedy-adding approach is demonstrated to be suboptimal, and the tradeoff curve between number of facilities and flow volume refueled is shown to be nonconvex.     

基于预算限制的鲜活农产品配送系统选址--分配模型研究

从鲜活农产品物流系统设计过程带有建站启动经费预算限制的角度出发，研究了一类带有预算限制的选址一分配问题。结合鲜活农产品对时间极其敏感这一特点，定义了价格因子P6将时间对产品质量的影响转移为对产品销售价格的影响，并在配送系统经济收益最大的目标下建立了带有预算限制的生鲜农产品选址一分配模型，给出基于贪婪的启发式算法，最后，用一个实际案例进行了演算。     

基于改进的DEA/AHP模型的人工成本投入产出效率评价

通过采用0.1-0.9标度这种更为简便实用的判断尺度,建立了具有完全一致性的互补判断矩阵,妥善解决了AHP判断矩阵的一致性问题,改进了DEA/AHP模型。并基于DEA模型和改进的DEAHP模型分别对盐城市22个行业2009年的人工成本投入产出进行效率评价分析。研究结果显示,基于改进的DEA/AHP模型的评价结果更加具有可区分性,具有更高的解析能力。     

Mathematical analysis of emergency ambulance location

Proper ambulance location is crucial in saving lives and reducing injury. To determine efficient and effective locations, it is necessary to evaluate both the spatial and temporal distributions of demand. Because of the complex nature of the ambulance response and transport activities, the problem is subdivided into a facility location problem and a vehicle allocation problem. A set covering model is modified to solve the location problem while a simulation is used to solve the allocation problem. Combining these two models provides a powerful methodology for systematically finding a satisfactory solution to the ambulance location problem.     

The application of goal programming techniques to the CPM problem

This paper demonstrates how goal programming (GP) can be used to incorporate considerations other than project completion time and total project cost into the typical CPM problem. In particular, factors such as share of the market, completion time of individual jobs, contractual agreements, and scarcity of resources such as men, materials and machines are taken into consideration. An example is provided to illustrate the use of the GP approach in a CPM problem.     

Data center supply chain configuration design: A two-stage decision approach

Data centers are special-purpose facilities that enable customers to perform cloud based real-time online transactions and rigorous computing operations. Service levels of data center facilities are characterized by response time between query and action, which to a large extent depends on data center location and data travel distance. Another aspect of service level is resource up-time availability, which is determined by data center configuration. Data center location and configuration decisions are, therefore, of great significance to ensure uninterrupted operations in customers of manufacturing and service industries relying on cloud-based computing resources. In this study, following a grid-based location approach, we present two mixed integer linear programming models for capacitated single-source data center location-allocation problems. The first model provides optimal locations, capacities and configurations of data centers, and allocation of demands to open facilities when there is no existing facilities in the region. Our second model considers the decision problem of meeting new demand when the existing demand is met by the already opened facilities. We term these newly arrived demand as replication demand, which results either from emergence of new users of existing customers at distant locations in the future, or as a means of increasing data resilience by creating data replication as a backup. To solve the decision problem for meeting primary and replication demand optimally, we propose a two-stage decision algorithm. The algorithm provides optimal locations, capacities and configurations for new data centers, capacity addition decisions to the existing facilities and subsequent allocation of demands. Both models and solution algorithm are implemented using AMPL programming language and solved with CPLEX solver. The models are found to be scalable and capable to provide high quality solutions in reasonable time.     

Improving access to health facilities in Nouna district,Burkina Faso

The Nouna health district in Burkina Faso, has a population of approximately 275,000 people living in 281 villages, and is served by 25 health facilities, as of 2006. For many people, the time and effort required in traveling to a health facility, which may demand a journey of many kilometers over poor roads on foot, is a deterrent to seeking proper medical care. In this study we examine how access to health facilities in Nouna may be improved by considering the configuration of the road network in addition to the locations of the facilities. We model the situation as a facility location–network design problem and draw conclusions about how best to improve the physical access of the health facilities. Our model shows the extent to which access can be improved when the road network is considered along with facility locations, in contrast to facility locations considered alone.     

Location and service mix decisions for a managed health care network

For managers of managed health care organizations, the problem of designing a competitive multiple facility network cannot be solved by existing mathematical models. This paper thus presents a nonlinear integer model for determining a facilities design strategy that embodies the economic tradeoffs encompassed in a competitive strategy: minimizing cost and maximizing market share. The integrated location and service mix model determines the number, location and service offerings of facilities that maximize profitability in a two-level hierarchical referral delivery network where an organization's market share is represented by a multiplicative competitive interaction model. To demonstrate the usefulness of the proposed integrated model, a series of problems is solved by an interchange heuristic and compared to the solutions derived by a simpler approach that ignores market competition.     

Siting a facility in continuous space to maximize coverage of a region

Siting facilities in continuous space such that continuously distributed demand within a region is optimally served is a challenging location problem. This problem is further complicated by the non-convexity of regions typically encountered in practice. In this paper a model for maximizing the service coverage of continuously distributed demand through the location of a single service facility in continuous space is proposed. To address this problem, theoretical conditions are established and associated methods are proposed for optimally siting a service facility in a region (convex or non-convex) with uniformly distributed demand. Through the use of geographic information systems (GIS), the developed approach is applied to identify facility sites that maximize regional coverage provided limitations on facility service ability.     

Minimising emergency response time of ambulances through pre-positioning in Dhaka city,Bangladesh

This study conducted a large-scale survey in Dhaka, Bangladesh; the survey involved 95 major hospitals, more than 3000 emergency room patients, and 2 of the largest ambulance operators. Currently, most ambulances are parked within the vicinity of hospitals and are either dispatched or fetched by the acquaintances of the patient on demand, resulting in lengthy round trips. Reducing the response time of ambulances would certainly improve the emergency service, and pre-positioning of the ambulances could be a solution to reducing the response time. This study used two approaches to address the problem. First, the location-allocation problem was solved to find the optimal number of ambulance locations by maximising the demand coverage. Second, separate location-allocation for the peak and off-peaks, using K-means clustering, was applied to systematically optimise the ambulance positioning in small clusters near demand points. These approaches could substantially improve the existing emergency response time. Distributing ambulances near demand points yielded greater improvements in response time than when the ambulances are stationed near hospitals.     

Sustainability in The Banking Industry: A Strategic Multi‐Criterion Analysis

The current paper aims to develop an effective and integrated MCDM model for the evaluation of the sustainability practices in the banking services, employing a multi‐stage, fuzzy MCDM model that integrates the Balanced Scorecard, fuzzy AHP and fuzzy TOPSIS. The approach aims to evaluate sustainability from the following four perspectives: financial stability, customer relationship management, internal business process and environment‐friendly management system. A real implementation dealing with the six largest commercial banks in India is discussed. The results highlights the critical aspects of the evaluation criteria and the issues in improving sustainable banking performances. Regarding the sustainability issues, it is shown that the environment‐friendly management system takes a back seat compared with the other criteria. Furthermore, the results show that there is a misunderstanding of the role that corporate social responsibility plays with respect to environmental issues. The developed evaluation model offers a valuable management tool for banks' administrators by assisting them in strategic choices in order to achieve their objective of sustainability and sustainable banking. Moreover, it offers a measuring tool with unique features that complements the emerging trend of integrated reporting considering uncertainty. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment     

Modeling integrated supply chain logistics in real-time large-scale disaster relief operations

The goal of this research is to develop a comprehensive model that describes the integrated logistics operations in response to natural disasters. We propose a mathematical model that controls the flow of several relief commodities from the sources through the supply chain and until they are delivered to the hands of recipients. The structure of the network is in compliance with FEMA's complex logistics structure. The proposed model not only considers details such as vehicle routing and pick up or delivery schedules; but also considers finding the optimal locations for several layers of temporary facilities as well as considering several capacity constraints for each facility and the transportation system. Such an integrated model provides the opportunity for a centralized operation plan that can eliminate delays and assign the limited resources to the best possible use.A set of numerical experiments is designed to test the proposed formulation and evaluate the properties of the optimization problem. The numerical analysis shows the capabilities of the model to handle the large-scale relief operations with adequate details. However, the problem size and difficulty grows rapidly by extending the length of the operations or when the equity among recipients is considered. In these cases, it is suggested to find fast solution algorithms and heuristic methods in future research.     

Assessment of CSR based supply chain performance system using an integrated fuzzy AHP-TOPSIS approach

The objective of this research was to identify Corporate Social Responsibility (CSR) criteria as well as propose and prioritise the alternatives to improve the supply chain performance system of an organisation. To meet the objective, firstly, CSR-based criteria, sub-criteria and alternatives were identified based on the literature review and discussion with the field experts, taken from automobile industries located at the Delhi region of India. Then, kappa statistics has been applied to check the internal consistency between identified criteria and sub-criteria. After finding the evidence of internal consistency, a hierarchical-type model has been developed and analysed using a multi-criteria decision-making as an integrated fuzzy analytical hierarchy process (AHP) and a fuzzy technique for order performance by similarity to the ideal solution (TOPSIS) approach. To make the results more robust and feasible, a sensitivity analysis has also been performed.     

改进AHP主观性的DEA/AHP新模型

本文提出了一种DEA(数据包络分析)与AHP(层次分析法)结合的新模型。该模型有别于目前国内很多将AHP作为约束锥的DEA混合模型。通过对模型的阐述和算例的验证,得到了DEA/AHP方法相对于DEA的优势。并指出了以AHP作为约束锥的DEA混合模型的不足,以及本文提出的DEA/AHP方法对于AHP主观性的改进,并实现了DEA方法中决策单元的完全排序。