جستجوی مقالات مرتبط با کلیدواژه « Location » در نشریات گروه « مدیریت »

Despite significant technological developments in today’s world, it is still plagued by all manners of natural and man-made disasters (such as earthquakes, floods, hurricanes, avalanches, war, terrorism, political unrest, etc.) which not only slow the process of sustainability development but also, when neglected, can inflict terrible and sometimes irreparable damage to a community’s well-being and prosperity. This issue requires an integrated logistics system that is scientifically and comprehensively designed to meet the needs of crisis management; a system with clear and predefined processes in which all components have predefined functions. Providing aid to the injured is one of the most important stages of crisis management, which must be planned before the accident because timely and efficient aid will greatly reduce human and financial losses. In order not to be surprised during natural crises, proper planning should be done in advance and under normal conditions.  Humanitarian logistics (HL) is considered one of the most important issues of disaster operations and management. However, the operations required for humanitarian logistics must be sustainable enough to function well under the uncertain and complex nature of disasters and crises. Many difficulties in the pre-disaster and post-disaster phases bring both human and economic losses, and practically ensuring the efficient design of humanitarian logistics operations seems essential. In this study, considering the importance of planning before disasters and also the mathematical optimization model for locating facilities and relief centers, articles published between the years 2004 and 2023 to examine optimization models in the field of humanitarian logistics have been studied. The purpose of the research is to familiarize with the current research process of humanitarian logistics, especially the optimization problem used to achieve various goals of the location of humanitarian logistics facilities and to provide future research directions.

In order to get an overview of the research fields and to know what articles exist in this field and who has done research in this field and other more comprehensive information, using the Web of Science website, the keywords that are considered in this research, have been searched. Regarding facility location issues, all types of resource location problems are included in this study, and the papers under study are classified into two categories based on deterministic and non-deterministic models.

In the deterministic models table, the type of objective function, decision variables, model type, and solution methods are included. In non-deterministic models, this study primarily covers the stochastic programming approach and robust optimization. Also, in the non-deterministic model’s table, the type of objective function, decision variables, non-deterministic parameters of the model, type of uncertainty, type of model, and solution methods are included. According to the reviewed articles and also by referring to the presented literature review table, it is possible to find the points that have not been addressed or have been addressed less.

Finally, this study can be useful for researchers in understanding the current trend of the optimization problem in humanitarian logistics and modeling techniques. Researchers can easily find out the research gap and help society through their research.

Designing a multi-objective multiple allocation-routing problem in a humanitarian supply chain is important because it improves efficiency and productivity in the supply chain. By designing a multi-objective multiple assignment-routing problem, we can consider different objectives at the same time and seek to optimize them. As a result, designing a multiple multi-objective allocation-routing problem in a humanitarian supply chain can improve the overall performance of the company and lead to the economic and social growth of the region.

In this article, an integer mathematical model for the allocation of essential product to all destinations through multiple hub allocation-routing coverage is presented in a way that reduces the cost of allocation and the number of possible paths for allocation in a humanitarian supply chain. The proposed model is able to estimate well the binary optimal solutions of the problem that is route and vehicle allocation through the solution using the scattering search method. Based on the solution of the proposed model, the shortest possible route for allocating essential items to different considered cities is provided. Also, the lowest possible cost has been determined for allocating the route for relief. Finally, the allocation of each vehicle according to their type to each city has been specified. This allocation of vehicles to each of the cities has been done in such a way that each of the vehicles covers each of the cities at least once.

Based on the obtained results, the lowest routing allocation cost was gained using the suggested model. The results of the research show that the proposed model improves both the efficiency and effectiveness of humanitarian aid logistics, and its findings provide valuable guidance for improving decision-making regarding route allocation, the type of dispatch vehicle and cost in the field of humanitarian logistics, and for designing a suitable strategy for Dealing with disasters will be beneficial in the future.

The events that occur suddenly as a result of natural and human actions and impose hardship on society are called Disasters. In recent years, due to changes in the Earth's climate, the number of natural crises, including earthquakes, floods, storms, etc been increasing. Thus, the need for disaster management and planning is felt more than ever. In this research, the aim is to model and solve the problem of locating local warehouses and allocating and controlling the inventory of normal and perishable items in post-crisis conditions. Because in the real world, the demand for affected areas for any reason, such as the severity of damage to areas and people, the possibility of aftershocks with higher intensity and in a short time after the initial earthquake, and the rate of death is not certain. In addition, in most of the conditions, the budget is not clear for the managers and it depends on the severity of the crisis, the support of humanitarian organizations, and public donations. S the budget is uncertain. Therefore, we considered uncertain demand and budget in this research. For this problem, a mixed-integer linear mathematical model has been developed. To solve the problem, GAMS software and the electromagnetic algorithm have been used for small-sized and large-sized problems, respectively. Numerical results on different examples show the efficiency of the proposed algorithm in terms of time and the quality of results.

Background and objective :

This study aim is to find the optimal location form backup land uses from the perspective of passive defense in Urmia City. This is an applied, descriptive, and analytical study. 

Method :

Data collection was done using documentary data, a field study, and a questionnaire. Participants were 10 experts in this subject, who were selected purposefully. The network analysis process (ANP) was used to analyze the data. A dynamic and comprehensive model was prepared to locate fuel centers, fire stations, and hospitals from the perspective of passive defense. 

Results:

 The findings showed that Ali Gorge neighborhood and a part of the Hezaran neighborhood were suitable places for fire stations. Ali Gorge neighborhood was a completely suitable location for fuel stations. Moreover, the neighborhoods of Ali Gorge and Haft-Asiab were completely suitable locations for the construction of hospitals. 

Conclusion :

It can be concluded that Ali Gorge neighborhood has more suitable conditions than other neighborhoods for locating backup land uses. Therefore, special attention should be paid to this neighborhood by the city managers.

Roadside units are crucial elements of intelligent transportation systems that provide vehicle–vehicle and vehicle–equipment information communication. Due to the high cost of installation, the deployment of roadside units is the most critical. Aim of this study is developing a model to optimize of roadside units placement to achieve maximum coverage. A multi–objective mathematical model presented, based on the three main parameters. These parameters are traffic volume, incident rate and adjacency to important centers, which determine for alternative points. The maximum coverage problem is NP–hard. Consequently, conventional mathematical methods are not accurate for large scale problem. A meta–heuristic method based on the greedy algorithm was developed which conciders marking points as definitive–select or non–selectable. Result of the model were evaluated through testing of three scenarios, 200, 500 and 1000 meters coverage in District 5 of Tehran by using MATLAB and the best one, 1000 meters was chosen with 71% coverage. Observations showed the effect of various parameters such as equipment coverage radius, number of equipment and budget on the results of distribution. This algorithm makes it possible to solve the problem on a large scale by using the geolocation of the candidate points.

This paper seeks to find the optimal number of hubs and their location to keep the preparation time and congestion in the hubs and costs at a minimum. Also, this study considers the tardiness time for the conditions that the customer's need is not answered in the specified time, which can help to make the problem conditions more realistic. Therefore, in this study, the scheduled time and the real-time system are considered. This paper considers the tardiness and congestion time for hub optimization problems with single, multiple, and multiple direct transport allocations. The decision variables in this model determine the number of hubs, the capacity of the hubs, and their location. Congestion and tardiness also affect service time, especially if the capacity and cost of hubs are limited.
This paper uses a mathematical model to solve the hub problem of optimizing the allocation – location of single, multiple, and multiple with direct transportation. GAMS software is used to find the optimal number of hubs and locations as two objective functions are optimized. The first objective function includes transportation costs, hub setup, and tardiness costs, and the second one consists of the handling time in the hubs and the congestion inside the hubs. The sensitive analysis is investigated for the service time based on the congestion and tardiness time.
This model is tested on AP (Australian Post) data for single, multiple, and multiple with direct shipping allocation models. This study also solves the exact model for 100 nodes allocated to all three models. The hubs' capacity, congestion, and tardiness determine the number of hubs. In this paper, hubs are considered small, medium, and large. Congestion levels are also considered changeable. In addition, a comparison is made between single and multiple allocations concerning cost and capacity limitation to investigate service time. The findings indicate that a hub with limited cost and capacity needs more service time. The lexicography method is also used to convert objective functions into one function.
The more the number of hubs increases, the total costs, including the transportation and hub establishment costs will also increase. Therefore, considering the transportation costs and the establishment of the hub, it can be said that single and multiple allocations can be used in some situations. However, multiple allocations with direct transport have the lowest transportation costs because goods based on the costs are transported through the non-hub and hub nodes. In general, the results indicate that using the multiple allocation model with direct transport can reduce the total transport cost, and a single allocation has the highest transport costs. This paper is helpful for managers and business owners who first want to identify points for building their product or service warehouse. Secondly, they want to have the most optimal type of allocation for transportation from different cities.

One of the most important problems for distribution companies (especially large online stores) is the design of docking stations, vehicle routing, and supply chain optimization. In this research, the distribution centers of Digi kala online store have been located. A multi-objective location-routing problem has been developed by meta-heuristic methods considering the principle of stability and time constraints. Based on the results of the proposed model, the effect of demand on the three objectives of time, cost, and environmental and social issues was investigated and it was shown that if demand increases, there will be a greater effect on time. In other words, increasing demand can create gaps that result in increased delivery time, and therefore this can lead to customer dissatisfaction in the long run. Increasing employment also leads to better environmental issues, but has no effect on cost or time. Also, the cost of transporting goods has no effect on environmental issues and time, but leads to increased costs.

In the management of the blood supply chain network, the existence of a coherent and accurate program can help increase the efficiency and effectiveness of the network. This research presents an integrated mathematical model to minimize network costs and blood delivery time in crisis conditions. In the present model, to ensure timely and sufficient blood supply, especially in crisis conditions, the new approach concentration of blood collection, processing, and distribution sites in the facilities, emergency transportation, pollution, route traffic (delivery delay), blood type substitution, and supporter facilities were used. Moreover, other important decisions, including locating all permanent and temporary facilities at three blood collection, processing, and distribution sites, and blood shortage, were also applied in the model. The proposed model was solved for several problems using the Augmented epsilon-constraint method. The results showed that deploying advanced processing equipment in field hospitals, the concentration of sites in facilities, and blood type substitution have significantly improved network efficiency. Therefore, managers and decision-makers can use the proposed approaches to optimize the blood supply chain network to minimize network costs and blood delivery time.

Nowadays, due to the increase in population and climate change, the probability of natural disasters such as floods and earthquakes are increasing. Therefore, the need for proper planning to reduce human and financial losses is felt more and more. Locating camps and   medical service centers is one of the measures that should be taken into account to deal with disaster conditions. In this research, camps and medical service centers’ locations have been investigated. According to the historical background of the city of Rudbar in the occurrence of a big earthquake and the location of this city on the active fault of Rudbar, this city was chosen for a case study.

Suitable places for the construction of camps and medical service centers were considered from previous researches and the opinion of the experts of the Center for Research and Resilience in Disasters and to rank the options, the compromise mixed solution method has been used.

At first, with the consultation of the experts of the Center for Research and Resilience in Disasters and Disasters and using previous researches, appropriate criteria were determined for prioritizing the candidate places for the construction of medical service centers and camps. Then, according to these criteria, the candidate places were first prioritized to determine the suitable place for the construction of medical service centers, according to the population of Rudbar city, 5 places were selected for the construction of medical service centers, and the other places were selected for the construction of the camp according to the appropriate criteria. In order to identify a suitable place for the construction of the camp, they were prioritized again. Hosp itals and schools are more suitable places to build medical service centers and schools and mosques are more suitable places to build camps.

The results show that the criteria of not being located on the fault, the presence of suitable infrastructure, and the distance from the disaster points are important criteria for choosing a medical service center, and criteria not being located on the fault, the presence of suitable infrastructure, and the distance from the medical service centers are important criteria for building a camp.

When it comes to providing aid to the victims of natural and unnatural disasters, the main goal of a relief chain is to provide the items needed by the victims such as water and food, medicine, shelter and other necessities to reduce the number of deaths caused by reduce the occurrence of disasters as much as possible; therefore, designing, developing and implementing a relief chain can play an important role in finding a suitable answer. The most obvious differences in dealing with the relief supply chain are the unpredictability of demand in terms of time, place, type, scale and volume. Other reasons such chains are the sudden occurrence of a large amount of demand and a very short opportunity to provide a large amount of goods, lack of resources including goods, relief forces, appropriate technology, transportation capacity, the need to provide timely and sufficient supplies after the accident, and the risks in the relief environment. In the present research, a mathematical model for the location-inventory problem for planning response to casualties is presented; also, due to the NP-hard nature of the problem considered, meta-heuristic algorithms were used to solve it.

The location of military bases and barracks within the urban context, along with the horizontal expansion of cities, has created many problems in the missions assigned to the armed forces and reduced the efficiency of barracks, which in itself is a serious threat to the proper performance of missions. This study aims to identify the dimensions and components of military barracks location by mixed methods. The statistical population of this study includes commanders and professors of armed forces universities (NEZAJA and NAJA) and structural equations with Smart PLS software have been used to analyze the data. In this research, the components of locating military barracks and their influential variables have been identified, then classified based on experts’ opinion, and finally suggestions for their improvement have been presented. The results show that the influential components on the location of military barracks are: territorial planning, geography of the region, principles of passive defense considerations, basic infrastructure and military indicators and type of units. Paying attention to the finding indicators can have a significant effect on the location of military barracks.

This study investigated the criteria influential in determining the construction site of the urban solid waste recycling centers and then determined the importance of each of these indicators. Then, in order to evaluate and rank the candidate locations, a new method based on the Multi Mora technique was introduced.

This descriptive survey is an applied study in terms of its purpose. As such, the required data were collected through a questionnaire. In the first phase, the potential indicators were identified in a library research. Moreover, to determine the weight of the indicators and score the items, the opinions of 14 experts in the field including the relevant executive managers and university instructors were sought.

The results of the study revealed that the three indicators of construction cost, current land cover, and soil cover were the most important ones playing a key role in determining the location of the recycling centers. After the potential locations were evaluated in District 22 of Tehran Municipality as a case study, three places which scored the highest were identified as the optimal recycling stations.

The criteria for locating waste recycling centers are dynamic in nature, and both their nature and weight along with the importance of each of them change over time. To this end, for each new case, relevant managers and officials should consider new indicators, including costs and other new issues, when deciding on a construction site for recycling centers.

Cities that used to grow relatively slowly in the past, today face a lot of new and complex problems because one of the most important and basic needs of the urban population is optimal access. To municipal services. One of the best strategies to solve this problem is to select and locate the optimal service using GIS. The aim of this study was to investigate the spatial distribution and location of urban services in the city of Kalishad and Sudarjan.

In this article, the research method is descriptive-analytical.

The research findings show that the surveyed services do not have an optimal location and do not have the power to meet the needs of citizens.

It is suggested that neighborhoods 2, 6, 3, which have a high population, be given priority in providing services, and by transferring or creating new service centers in these neighborhoods, the service problem will be largely solved. Lands along the Zayandeh River can also be used as green space, recreational space and even as a tourist village.

Traffic police currently use various methods to carry out their inherent missions, including increasing patrol teams and using various equipment. At the same time, it still faces various problems in performing its duties. Therefore, in order to better implement the regulations and the citizens' satisfaction with the performance of the police, it needs to review its working methods and performance. By deploying police car patrols in appropriate places and managing the city's traffic by using surveillance cameras, in the event of traffic disruptions such as vehicle breakdowns or traffic accidents, etc., car patrols can be reduced to a minimum. Possible time to fix the problem.

The research method is descriptive-analytical. To analyze the data, spatial statistics analysis and statistical-graphical methods in the form of GIS have been used. AHP method and Expert Choice software have been used to prioritize the criteria and sub-criteria for locating vehicle patrols.

The results showed that the accident criterion is the most important and the topographic criterion is the least important among other criteria. Also, the fatal accident sub-criterion with a weight of 0.386 had the highest weight and the distance sub-criterion from residential areas had the lowest weight compared to other sub-criteria.

By describing the current situation of police car patrols and identifying its shortcomings, the effective variables in the location of police car patrols were identified and prioritized. Also, how to position correctly based on priorities was obtained.

In these days many people lost their lives and properties to natural events like floods, earthquakes, and storms.  planning before the occurrence of a crisis in order to come up against it is very important and decreases the number of injured and response time.in addition, choosing the number of emergency stations, production centers, and their location is effective for response teams and maximum the use of equipment and space. In this article a two objective mathematical model that minimum costs of transporting relief items and Relief times is proposed, the model also helps us to choose the number of server centers and production centers according to the severity of the earthquake.

Besides in this research we assume that injured people are in three categories green, red and yellow depends on the severity of their injury. Since the problem assumes for programming before the crisis, the proposed model is solved in two-stage. In the first stage, we assume that all injured and relief items transport on time. Then in the second stage, we solve the model with the assumption that we may make some mistakes in the predictions of capacity and demand especially when we confront a drastic earthquake and for this reason, some of the injured people can't transport on time. The proposed model is solved in GAMS with the LP-metric method.

Solving the model shows that patient classification helps us decide which service centers to send relief items to and which centers do not in cases where we have a shortage of resources and cannot send enough relief items. The same is true when ambulances and helicopters do not have enough space to evacuate the injured, in this case, the model helps us decide whether or not to send patients, in such a way that the time of sending items and patients and non-service costs are minimized.

Performance of the model evaluates with solving different examples, Model sensitivity analysis results show that predictions about the number of injuries and the also the costs that we assume for Penalty of not sending equipment and injuries are some of the most effective parameters in the model result. Also, our predictions about the percentage of injured who turn to green, yellow and red patients and the percentage of injured yellow who turn to the red patient has an important effect on the number of patients referred to service centers and the allocation of medical items to service centers.

Despite the advancement of technology and the emergence of innovations in the field of healthcare, scientists have not yet been able to find a suitable alternative to human blood. As a result, inventory management of blood and blood products has always been a major concern of the medical community. Among blood products, platelet management is very important because of their specific usages and their rapid perishabilities. The main objective of this research is to present a platelet supply chain design for decreasing the number of shortages and wastages simultaneously.

In this study, a mixed nonlinear location-inventory model is presented by using inventory concepts in order to manage platelet inventory in blood centers and hospitals and locating collection facilities to reduce platelet supply chain costs. The proposed location-inventory model has approximately converted into mixed linear programming using the piecewise linearization method and then has been solved with the Gams software.

Using the proposed model, blood centers are able to meet a high percentage of hospital demands, which reduces the number of platelet shortage units and supply chain cost. Also, using inventory concepts and better hospital assignment to blood centers with FIFO policy, the restriction of wastage on the number of lost units in hospitals and blood centers will be removed.

Using the developed contribution and applying inventory control and economic order quantity (EOQ) relations, the platelet inventory in the blood centers can be managed in such a way that in each period the maximum demand of hospitals has been met and the shortage has been reduced. Also, due to the specific features of the blood, platelets would be kept in more proper conditions, which will reduce the wastes in hospitals. In addition, the number of blood donors can be improved by using mobile blood collection facilities.

Relief of injuries is one of the most important stages of crisis management that should be planned for it before theincident. Timely and productivity relief will significantly reduce the financial and human losses. Considering thisnecessity, in this paper, proposed a mixed-integer mathematical model of multiple transfer points and facilities locationfor the formation of a relief chain during the earthquake crisis, which facilities includes hospitals, rescue centers,warehouses and shelters. Screening the injuries according to the triage system and providing outpatient health care atthe transfer points, transfer the yellow injuries to the relief centers, dual transfer of the red injuries to the hospital, payingattention to the type of goods needed at any point, and finally, adding budget constraint to set up facilities are the paper’sassumptions that developed the transfer points and facilities location model. To evaluate the model in real term a casestudy was conducted in south-central regions of Tehran. Model was once solved with specified number of facilities, andagain with consideration of budget constraint, in the second condition, better and more practical results were obtained. Asthe budget increases, the number of transfer points increases that indicating the importance of them in reducing the relieftime. Therefore, the establishment of transfer points is an effective strategy in the efficiency of the relief process duringa crisis. Attention to the distribution of hospitals in the city for the construction of new hospitals, the establishment of airrescue infrastructure in hospitals, identification of resistant buildings to change their use in crisis as a backup facility, andtraining the process of relief to citizens, are important solutions in the proper functioning of the relief chain

Customers require various service facilities including department stores, ATMs, and gas stations the use of which has become a daily routine. Some researchers believe that location choice of such facilities should be based on maximum population coverage within the network. The current research set out to identify potential factors that may bear an impact on location selection of ATM machines through exploring the existing literature on banking and interviewing experts in the field. Moreover, it aimed to prioritize the most important factors among those already specified through mathematical modeling. The findings emerging from the literature and expert review indicated 15 factors influencing ATM location decisions that were further subcategorized into four major factor sets of economic, competitive, coverage, and investment - legal. The results of mathematical modeling weighing revealed the priority of factors with Coverage, weighing 0.43, as the first and most important one followed in significance by economic factors, weighing 0.23, competitive factors, weighing 0.19, and investment - law factors, weighing 0.13. The results of this study also indicated that each of the four factors sets could impact decision-makers differently; therefore, bank managers are suggested to vary their decisions with respect to each of the factors to achieve optimal effectiveness.

Locational decisions, routing and allocation in supply chain management philosophy is undoubtedly one of the most important issues that affect the frequency of the supply chain cost reduction and customer satisfaction. This paper presents an integrated approach to the distribution network. The objective function of the proposed mathematical model consists of minimizing the total costs associated with transportation and warehouse rental costs and also minimize the risk of system. The model has high computational complexity and the exact method of solving it is not possible in a reasonable time. The result is an innovative multi-objective algorithm known as the objective harmony search algorithm is presented. To demonstrate the effectiveness and efficiency of the proposed algorithm to solve the model using the Taguchi method algorithm parameters are adjusted in the best possible rates. Then a random sample of the issues and the performance of the proposed algorithm with NSGA-ǁ and NRGA evaluated.

Introduction &

Urban symbols as a significant element of the city are a valuable tool for introducing the identity of the city. Which can be a full-fledged mirror of the identity and culture of the city. Identity crisis has become a complication of urbanization, which is reflected today in chaotic cities devoid of cultural and social values. The use of symbols with specific religious concepts that express our historical, cultural and religious identity in urban spaces causes more communication between citizens and identification of city residents. The purpose of this study is to analyze the role of urban symbols in identifying a place in the city Is Semnan.

present study as an applied study is based on descriptive method of correlation type. statistical population of 185129 people in semnan city and sample size were 385 persons according to the cochran formula. to analyze the data and test the hypotheses, spss software has been used. in order to collect data and information, a questionnaire was constructed and the questionnaire was used in the sample of sample society (citizens)to assess the validity of the research tool by cronbach's alpha coefficient. Cronbach " s alpha coefficient on indices of measurement (901 / 0)is the validity of the research tool.

The findings of the study show that the symbol of the city in Semnan does not correspond to the beauty and appropriateness of the culture of the region. The equipment of the city symbol in the city of Semnan is not well done in terms of location.

Urban symbols can identify cities, provided that specialized people (architect, sculptor, urban planner) are used in its design and installation.