共查询到20条相似文献，搜索用时 15 毫秒
1.
《Socio》2020
This paper presents a stochastic optimisation model for locating walk-in clinics for mobile populations in a network. The walk-in clinics ensure a continuum of care for the mobile population across the network by offering a perpetuation of services along the transportation lines, and also establishing referral systems to local healthcare facilities. The continuum of care requirements for different diseases is modelled using coverage definitions that are designed specifically to reflect the adherence protocols for services for different diseases. The risk of not providing the required care under different realisations of health service demand is considered. In this paper, for a multi-disease, multi-service environment, we propose a model to determine the location of roadside walk-in clinics and their assigned services. The objective is to maximise the total expected weighted coverage of the network subject to a Conditional-Value-at-Risk (CVaR) measure. This paper presents developed coverage definitions, the optimisation model and the computational study carried out on a real-life case in Africa. 相似文献
2.
考虑到回收量的不确定性将影响回收网络的稳健性,建立了基于第三方企业的再制造逆向物流网络模糊规划模型,将废旧品的回收量和丢弃率用梯形模糊数表示,然后利用模糊机会约束规划方法将模型转化为清晰等价形式。通过示例数值仿真,表明了该模型的可行性,同时分析了不同置信水平下,最优选址策略和目标函数值的变化情况。 相似文献
3.
《Socio》2023
During the preparation before a hurricane makes landfall, affected individuals may be asked to evacuate. Large and small-scale evacuations can cause rapid increases in the demand for gasoline fuel. However, during a hurricane vessels carrying gas may be delayed and/or rerouted, adding to the difficulty of providing the necessary gas in affected areas. In this work, we determine alternate delivery locations and times for vessels carrying fuel that are scheduled to arrive and deliver fuel at ports impacted by an approaching hurricane. Motivated by Hurricane Irma in Florida, we develop a multi-period stochastic scheduling model that incorporates hurricane (weather) advisories, fuel delivery schedules, port storage capacities, and port docking capacities. Our model determines the best schedule based on two objectives: (1) minimize the total unmet demand at each port, and (2) minimize inequities in unmet demands among the ports. We also present a case study and a numerical experiment based on fuel delivery data from ports in Florida. Among our key findings is that port availability is the driving factor in determining feasible schedules for vessel gas deliveries. We also present a scheduling heuristic that dynamically adapts to weather advisories so as to minimize the impact of unmet demand in the affected areas. 相似文献
4.
《Socio》2020
The need for efficient blood supply is of more significance in the event of disasters, when there is a lack of coordination between distribution and inventory management. The recent earthquake in Kermanshah province in Iran is among such cases that confirmed the need for coordinating such schedules. In this respect, a two-stage stochastic programming (SP) approach is presented for planning supply of blood after disasters that can assist in inventory decisions under hybrid uncertainty, minimizing the shortage and wastages. The uncertainty stems from imprecise parameters and scenario variability, and a robust-fuzzy-stochastic programming (RFSP) approach is devised to hedge against the uncertainty. The perishability of blood, the substitutability of blood groups, and the age-based characteristic of blood are taken into account to make the model more reliable. The compromise programming is applied to solve the multi-objective model. The results illustrate that the RFSP model can make a reasonable trade-off between mean value, feasibility robustness, and optimality robustness, which results in a robust and reliable solution under disastrous conditions. 相似文献
5.
《Socio》2020
This paper proposes a novel two-period option contract integrated with supplier selection and inventory prepositioning. A two-stage scenario-based mixed possibilistic-stochastic programming model is developed to cope with various uncertainties. The first stage's decisions include supplier selection and capacity reservation level at each supplier/period and the level of inventory prepositioning. Furthermore, decisions regarding the time and exercised amount are made in the second stage. Applicability of the model is validated through a real case study. Finally, several sensitivity analyses are conducted to examine the effect of important parameters on the solutions to gain useful managerial insights. 相似文献
6.
《Socio》2018
We study networks of facilities that must provide coverage under conditions of uncertainty with respect to travel times and customer demand. We model this uncertainty through a set of scenarios. Since opening new facilities and/or closing existing ones is often quite expensive, we focus on optimal re-configuration of the network, that is finding a facility set that achieves desired thresholds with respect to expected and minimal coverage, while retaining as many of the existing facilities as possible. We illustrate our model with an example of Toronto Fire Service. We demonstrate that relocating just a few facilities can have the same effect as opening a similar number of new ones. We develop exact and approximate solution approaches and test them with computational experiments. Algorithm based on Tabu Search (with certain novel components) appears to be particularly successful for this problem. We also analyze the multi-objective version of the problem, where the expected and minimum coverage levels are treated as objectives in addition to the objective of maximizing the number of pre-existing facilities in the final location set. 相似文献
7.
《Socio》2023
In the current paper, a model of possibilistic location-allocation is proposed for designing a multi-period bi-objective humanitarian logistics network that pursues a reduction in the total cost and maximizes the total network coverage. The model considers the inventory management of perishable relief items and the flow of affected and wounded people in pre-disaster and post-disaster phases, simultaneously. Moreover, wounded people are categorized according to the injury severity. The uncertainty associated with key parameters is also addressed. To handle the uncertainty, a fuzzy chance-constrained programming method originated in the Me measure is used. The purpose of this measure is to prevent the extreme attitudes of the decision maker by considering the combination of possibility and necessity measures and using the optimistic-pessimistic parameter. This paper presents a solution procedure derived from a fuzzy interactive programming approach and two meta-heuristic algorithms, imperialist competitive algorithm and invasive weed optimization, so as to solve the study model. As for the validation of the proposed model and solution procedures, a number of test problems have been generated. A real-life case study is also implemented to instantiate whether the proposed model is applicable or not. 相似文献
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9.
企业的供应链是一项系统工程,是企业的产品从生产、分销、零售,最后到达消费者手中的一个复杂的链条。阐述了供就链的内涵及演变,分析了企业物流供应链会计工作的难点,提出了会计对企业物流供应链优化的措施。 相似文献
10.
物流企业的现代化发展和激烈的市场竞争对物流企业业务流程提出了新的要求,首先概述了传统物流业务流程方案的现状及存在的问题,然后以航空物流公司为例,制定了一种新的物流企业业务流程优化方案并提出了相应的保障措施,通过流程的优化设计,以实现物流企业综合竞争力的提升。 相似文献
11.
本论文在研究大量文献的基础上,总结并阐述了基于供应链的物流模型、供应链运输决策机制的基本概念、目的以及决策参与者,接着从理论分析的角度研究供应链中物流管理的运输决策机制的内容:运输量的预测、第三方物流提供者选择决策、运输工具决策、运输价格决策以及物流运输路线优化决策等,以保证运输决策正确进行,降低运输成本以及有效的进行供应链管理。 相似文献
12.
不同的碳排放约束会对供应链网络设计的选址及工厂环保等级的选择产生影响。文中综合考虑环境投资决策、网点选择以及路径的选择等问题,以总运作成本、生产和运输途中碳排放量最小为目标,建立不同需求情境下、需求不确定的多产品双目标混合整数规划模型,结合ε约束法设计了基于情景的求解算法。最后通过算例分析,验证模型和算法的有效性。 相似文献
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对供应链系统与物流会计的内涵及两者间关系进行了论述,指出物流会计核算的重要性,针对目前我国物流会计核算现状及存在的问题,提出了基于供应链系统的物流会计核算优化策略。 相似文献
15.
通过对不同订单驱动方式的制造企业的订单类型、订货备货分离点、订货批量和制造运作实施等方面进行研究,以供应链上企业之间的物流运作为载体,构建订单驱动制造企业的供应链模型,指出该供应链模型的物流服务运作优化策略,为该企业所在行业的产业结构调整和供应链结构优化提供参考。 相似文献
16.
针对汽车零部件供应、整车生产制造、整车销售的关键流程存在的问题,应用RFID技术进行流程优化,以减少非增值活动从而将更多的资源投入到核心增值业务中,对于提升企业的市场竞争力有重要的现实意义。 相似文献
17.
This paper presents a Pareto-based bi-objective optimization of hazardous materials vehicle routing and scheduling problem with time windows and shows its application to a realistic hazardous material logistics instance. A meta-heuristic solution algorithm is also proposed, which returns a set of routing solutions that approximate the frontier of the Pareto optimal solutions based on total scheduled travel time and total risk of whole transportation process. It works in a single-step fashion simultaneously constructing the vehicle route and selecting the optimal paths connecting the routed locations from a set of non-dominated paths obtained in terms of travel time and risk value. 相似文献
18.
介绍了服务供应链理论的兴起,随着服务业的快速发展服务供应链正逐步成为供应链研究的新趋势。介绍服务供应链在港口物流中的应用。以港口服务供应链为背景运用排队理论对服务供应链中的M/M/n排队系统进行了建模,得出结果并举例说明。对排队系统进行了优化,得出排队系统的有效管理及优化对于服务供应链的运营异常重要。 相似文献
19.
《Socio》2023
As an abrupt epidemic occurs, healthcare systems are shocked by the surge in the number of susceptible patients' demands, and decision-makers mostly rely on their frame of reference for urgent decision-making. Many reports have declared the COVID-19 impediments to trading and global economic growth. This study aims to provide a mathematical model to support pharmaceutical supply chain planning during the COVID-19 epidemic. Additionally, it aims to offer new insights into hospital supply chain problems by unifying cold and non-cold chains and considering a wide range of pharmaceuticals and vaccines. This approach is unprecedented and includes an analysis of various pharmaceutical features such as temperature, shelf life, priority, and clustering. To propose a model for planning the pharmaceutical supply chains, a mixed-integer linear programming (MILP) model is used for a four-echelon supply chain design. This model aims to minimize the costs involved in the pharmaceutical supply chain by maintaining an acceptable service level. Also, this paper considers uncertainty as an intrinsic part of the problem and addresses it through the wait-and-see method. Furthermore, an unexplored unsupervised learning method in the realm of supply chain planning has been used to cluster the pharmaceuticals and the vaccines and its merits and drawbacks are proposed. A case of Tehran hospitals with real data has been used to show the model's capabilities, as well. Based on the obtained results, the proposed approach is able to reach the optimum service level in the COVID conditions while maintaining a reduced cost. The experiment illustrates that the hospitals' adjacency and emergency orders alleviated the service level significantly. The proposed MILP model has proven to be efficient in providing a practical intuition for decision-makers. The clustering technique reduced the size of the problem and the time required to solve the model considerably. 相似文献