A taxonomy for emergency service station location problem

The emergency service station (ESS) location problem has been widely studied in the literature since 1970s. There has been a growing interest in the subject especially after 1990s. Various models with different objective functions and constraints have been proposed in the academic literature and efficient solution techniques have been developed to provide good solutions in reasonable times. However, there is not any study that systematically classifies different problem types and methodologies to address them. This paper presents a taxonomic framework for the ESS location problem using an operations research perspective. In this framework, we basically consider the type of the emergency, the objective function, constraints, model assumptions, modeling, and solution techniques. We also analyze a variety of papers related to the literature in order to demonstrate the effectiveness of the taxonomy and to get insights for possible research directions

A taxonomy of logistics innovations

In this paper we present a taxonomy of supply chain and logistics innovations, which is based on an extensive literature survey. Our primary goal is to provide guidelines for choosing the most appropriate innovations for a company, such that the company can outrun its competitors. We investigate the factors, both internal and external to the company, that determine the applicability and effectiveness of the listed innovations. We support our suggestions with real world cases reported in literature

A taxonomy of supply chain innovations

In this paper, a taxonomy of supply chain and logistics innovations was developed and presented. The taxonomy was based on an extensive literature survey of both theoretical research and case studies. The primary goals are to provide guidelines for choosing the most appropriate innovations for a company, and help companies in positioning themselves in the supply of chain innovations landscape. To this end, the three dimensions of supply chain innovations, namely the goals, supply chain attributes, and innovation attributes were identified and classified. The taxonomy allows for the efficient representation of critical supply chain innovations information, and serves the mentioned goals, which are fundamental to companies in a multitude of industries

A NOVEL METHODOLOGY FOR TIME PLANNING OF RESOURCE-CONSTRAINED SOFTWARE PROJECTS WITH HESITANT FUZZY DURATIONS: A CASE STUDY

Time planning of software projects is a complex process for almost all companies. Uncertainties about effort required may cause underestimation or overestimation. Thus, enterprises may encounter an unrealistic schedule and choosing the appropriate planning method becomes crucial. This paper presents a novel integrated decision support methodology for time planning of resource constrained software projects. For this aim, after identifying the effective criteria by the help of expert judgments from the Turkish Information Technology industry and literature review, we find their priorities by Hesitant Fuzzy Pairwise Comparison and calculate estimated effort for the projects. Then, we use the priorities of criteria and estimated durations of the projects in a mathematical programming model proposed to find starting and finishing (delivery) time of the projects. Furthermore, we apply the methodology for solving the project time planning problem of a Turkish software company. It is seen that the proposed method provides efficient schedules

A new model and tabu search approach for planning the emergency service stations

The location planning of emergency service stations is crucial, especially in the populated cities with heavy tra±c conditions such as Istanbul. In this paper, we propose a Backup Double Covering Model (BDCM), a variant of the well-known Maximal Covering Location Problem, that requires two types of services to plan the emergency service stations. The objective of the model is to maximize the total population serviced using two distinct emergency service stations in di®erent time limits where the total number of stations is limited. We propose a Tabu Search (TS) approach to solve the problem. We conduct an extensive experimental study on randomly generated data set with di®erent parameters to demonstrate the e®ectiveness of the proposed algorithm. Finally, we apply our TS approach for planning the emergency service stations in Istanbul

A multi-period double coverage approach for locating the emergency medical service stations in Istanbul

We consider the multi-period location planning problem of emergency medical service (EMS) stations. Our objective is to maximize the total population serviced by two distinct stations within two different response time limits over a multi-period planning horizon. Our aim is to provide a backup station in case no ambulance is available in the closer station and to develop a strategic plan that spans multiple periods. In order to solve this problem, we propose a Tabu Search approach. We demonstrate the effectiveness of the proposed approach on randomly generated data.We also implement our approach to the case of Istanbul to determine the locations of EMS stations in the metropolitan area

İstanbul’da acil yardım istasyonlarının yerlerinin planlanması

Acil müdahale gerektiren afet, kaza, hastalık ve benzeri her türlü durumda, hizmete ihtiyaç duyan kişiye ulaşma süresi can güvenliği açısından çok kritiktir. Bu sebeple, acil yardım istasyonlarının etkin planlanması çok önemlidir. Özellikle yoğun nüfus ve trafik faktörüne sahip İstanbul gibi büyük şehirlerde bu planlamanın önemi daha da artmaktadır. Bu çalışmada, İstanbul Büyükşehir Belediyesi (İBB) İtfaiye Daire Başkanlığı bünyesindeki Acil Yardım ve Cankurtarma Müdürlüğü’ne bağlı Hızır Acil Yardım istasyonlarının tek ve çok dönemli yerleşim planlanması problemi ele alınacaktır. Bu problemler için, Yöneylem Araştırması literatüründe iyi bilinen Küme Kapsama ve Enbüyük Kapsama modellerini temel alan Yedek Çift Kapsama modeli önerilmektedir. Tek dönemli modelin çözümü mevcut yazılımlar kullanılarak mümkün olmakla beraber karar değişkeni ve kısıt sayısının arttığı büyük ölçekli problemler ve çok dönemli durum için optimal çözümler elde edilememektedir. Bu nedenle gerek büyük ölçekli problemlerin çözümü gerekse modelin çok dönemli çözümü için üç sezgisel yöntem önerilmiştir. Makalede; İstanbul için etkin bir acil yardım yerleşim planı belirlenirken kullanılan modeller, yöntemler ve çözümler tartışılacaktır

The Relationship of White Matter Hyperintensities with Depressive Symptoms and Daily Living Activities in Early-Stage Alzheimer's Disease Patients

Introduction: Cerebral white matter hyperintensities (WMHs) detected on magnetic resonance imaging scans are frequently seen in both Alzheimer's disease (AD) and depression patients and believed to play an important role in cognition and mood. Depressive symptoms and depression may accompany AD in all stages of the disease. The aim of the study was to evaluate the relationship of regional WMHs with depressive symptoms, cognitive status, medial temporal lobe atrophy, and daily living activities in early-stage AD patients