Sharif Digital Repository

In this research, we propose a formulated approach to locate and allocate two level of a three-level closed-loop supply chain consist of a number of capable points production facilities, redistribution centers and customer clusters for multiple products in multiple time periods. Also, we consider environmental aspects in this supply chain network by taking into account an objective function, aside from cost objective function, in the template of emitted carbon dioxide. In this research for the first time we consider vehicles’ emitted CO2 different in each period which is a result of gradual depreciation of vehicles. In the end for the sake of validating model’s performance we developed few... 

Environmental problems and the consequent governmental regulations, has led supply chains into reverse and closed-loop supply chains. Application of problems such as "Vehicle Routing Problem” has diminished in the closed-loop supply chain, and instead of them, the problem of "Vehicle Routing Problem with Deliveries and Pickups" has become more important. On the other hand, tendency of supply chains to running information in the chain in a desired way, has led to grow the attention to establishing policies of “Vendor Managed Inventory". It seems that by tending the supply chains to closed-loop supply chains which are utilizing the policy of "Vendor Managed Inventory", application of problems... 

Optimizing multi-period modern distribution system is a challenging task due to high costs of constructions in urban areas and importance of fast and cheap goods delivery to customers. Various logistic techniques have been proposed to solve this issue. In this study, a new method is suggested to convert the strategic problem of finding depot location into a tactical problem. In addition, a vehicle routing method for multi-period distribution systems in high demand periods have been developed. For modeling this location-routing problem two objective functions have been considered as fallows minimizing the total time in the system to satisfy customer demand and operating costs. To solve this... 

This thesis studies a multi-product location-routing-inventory problem in which location-allocation, inventory and routing decisions are to be taken in a three-level supply chain including suppliers, depots and customers. Each product for each depot could be supplied by more than one supplier and each supplier has a limited supplying capacity per period. Products are distributed from depots to customers by a homogeneous fleet of vehicles. Backlogging is allowable for each customer on the condition of not exceeding a fraction of customer’s demand. A mixed-integer programming formulation is presented to describe the problem then a new hybrid heuristic algorithm based on the simulated annealing... 

Success in a business will be met by the different factors, of which one of the most important is design and execution of a good business model upon the inauguration of each company. Indicating the commercialization of innovations and innovative commercial ideas, it shows the productivity of innovation. Outsourcing the Training management in organizations is an issue the world pioneer organizations feel its necessity. Training systems in organizations have limited resources, don't have the required knowledge and financial sufficiency for effective execution of all Training processes. Therefore, Training management outsourcing may be a good alternative for meeting perspective and facilitating... 

In this thesis, two Inventory-Routing Problem models, under vendor managed inventory policy are presented. In the first proposed model, despite the previous researches, transshipments between retailers are permitted and the problem is modeled by the assumption of reverse flow in the distribution network. Based on the first model, we also formulate a new model for the Pallet managing problem. Since the inventory routing problem is known as NP-Hard, genetic and variable neighborhood search algorithm has been applied to determine an acceptable upper bound for the first model in different instances. In the next step a Lagrangian relaxation method is developed for finding a near optimal solution... 

Logistics activities and matters related to supply chain management play an important role in the success of supply chain in today’s competitive business environment. The success of an organization depends on the proper functioning of the whole supply chain organization. SCOR model as a reference model for supply chain management is a suitable framework to manage all aspects of the supply chain and enables the creation of an appropriate and efficient structure in supply chains. In this thesis the Procurement department of a petrochemical company is examined and the current state of the supply chain is explained and then based on the SCOR model, in 4 areas: Performance (indices), Processes,... 

In this study we addressed the problem of separated waste management. Investigating the literature on location routing problem, reverse logistics, waste management, and countries’ performance in the field, we proposed a novel method for gathering household waste that inspired from prosperous metropolises and took into account the particular situations of developing countries. As a matter of fact, the proposed method is an extension of location routing problem; it’s a bi-echelon network of facilities and multi-compartment vehicles connected via reverse cross docks. The problem is formulated using a mixed-integer linear model with 3 economic, social, and environmental functions; with respect... 

This paper studies a multi-product, multi-period location- routing- inventory problem in a three-level supply chain including suppliers, cross-docks and customers. Each cross-dock could be supplied by more than one supplier and each customer could be supplied by more than one cross-dock. In the first phase we find the best locations for the cross-dock and allocate them to customers and suppliers by considering inventory costs. . Then, in the second phase Products are distributed from cross-docks towards customers using Heterogeneous vehicles. In this article the option for split delivery is enabled and furthermore, backlogging is allowable for each customer. The model presented in this... 

This paper studies a multi-product, multi-period, multi-allocation hub location problem based on real case in domestic automotive industry. As 3PL companies spread, using dynamic hubs in a contractual manner becomes passible; So in this paper the hub set is the combination of both static and dynamic hubs. The nodes are suppliers, sites and dealers of a supply chain that have certain demand of each product in each period. In this problem backlogging is allowable and causes penalty. Different transportation modes like road and railroad are usable just in hub network. Direct transmission is possible and candidate hubs are capacitated with multi suggested capacities. A mixed integer programming... 

This thesis studies a multi-commodity, multi-period three layer cross-docking network design problem. It is based on a case study in the automotive industry to optimize the flow of auto-parts from automakers to the production sites. The use of cross-docks as a facility for the aggregation point in the supply chain, allows the rapid separation of goods to be sent to demand nodes. The problem is studied in two phases; the strategic phase for the location-allocation of cross-docks and the tactical phase for the routing of heterogeneous road transportation fleet. A mixed-integer programming formulation is presented for each phase to define the problem. Genetic and harmony search meta-heuristic... 

This thesis introduces a inventory-routing problem under a vendor managed inventory strategy in a two-echelon supply chain. The VMI Routing problem in this study consists of multiple suppliers, multiple retailers and a single item. The suppliers plan inventory replenishments for retailers based on deterministic demand over multiple planning period. Also they allow stock-outs at retailers, which are considered lostsales. Transshipments are allowed, neither between suppliers nor between customers. Retailers can be supplied just by one assigned supplier. Model also considers some constraints on time and capacity. A mixed integer programming formulation is presented to describe the model. We... 

This thesis studies a multi–period location–routing–inventory problem in a three layer supply chain including manufacturers, distribution centers and customers with consideration of capacity constraint in distribution centers and heterogeneous fleet of vehicles. Moreover, the demand parameter is considered uncertain and there is no available information about distribution function of demand parameter. For handling problem uncertainty, Bertsimas and sim robust optimization approach is used and a mixed integer programming is presented for both deterministic problem and robust counterpart problem. Then simulated annealing and genetic algorithms are proposed to solve the model.... 

Increasing the performance and efficiency of the transportation system is one of the issues that has attracted the attention of many managers and experts in the industrial sector during the last decades, which aims to deliver the product to the customer in the earliest possible time with minimum cost. Therefore, it appears crucial to shed light on two aspects of the issues in this regard. The first one is to create routes functioning as flow transmission interface between many origins and many destinations and to satisfy the allowable time of tours in each route. The other one is the route that vehicles must take within the window time of each destination point. It should be pointed that the... 

The results also have shown that holding costs and inventory play key roles because of business various conditions and external risk encountering. As a result, supply chain systems have to decrease their inventory amount.In this study, a location-routing-inventory model hypothesizes using risk pooling in distribution center warehouses and their combination in order to decrease the inventory costs such as inventory holding and safety stock costs.(it is because of costumer uncertain demand and lead time from supplier to distribution center and from distribution center to costumers) In this model, in addition to decrease the inventory costs, DC establishment costs and transportation costs that... 

Persian Gulf with 21 Iranian islands and various ports from Makran’s coast in the south east of the country to Khorramshahr port in the southwest with significant potential for promotion of tourism industry and transportation of marine passengers between the coastal provinces of the country and the neighboring countries of the southern border of the Persian Gulf. The shipping of the sea includes different types of floats with different passenger capacities and strokes that the floating right selection is appropriate to the type of trip and the number of passengers which including the various costs.In summary, what we are looking for in this research are:
1.Select location or locations as... 

Because of some limitations, tourists can not visit all the attractions during their one or multiple-day trip. So, they need to select the best places worth to visit based on information that they gathered via the internet, magazines, tour guides, etc. Also, they should choose the best route to the selected place, considering its visiting time and ways conditions. Other factors such as visiting days/hours and the timetable for a place, entrance fees and the other limitations should be considered simultaneously. These requirements and questions are all discussed as a tourist tour plan problem in the field of operations research. In this research, different kinds of tour planning problems have... 

In this thesis, a new hub-and-spoke location problem is investigated in which, the location of spoke nodes should be decided upon, in addition to the location of hub nodes. Three research problems are investigated: In the first problem, the goal is to determine both hub and spoke node locations. In this problem, the objective function considers the following costs, to be minimized: flow transportation costs, lost demand costs, in addition to the hub and spoke location costs. The demand distribution among different nodes follow the gravity rule, and the hub network is considered to be fully connected. Following the gravity rule, the demand among different node is not set a priory and depends... 

This research solves a Location-Routing model based on the data of Tejarat bank branches in Tehran. The goal of the model is to minimize the cost of building & operating bank treasuries, optimize the cost of money transferring to branches of the bank & reduce the stealing risk. Because of the wide range of definitions for risk, time parameter is used as risk factor for its importance in bank money car stealing. Non-dominated Sorting Genetic Algorithm which is a common algorithm in multi-objective optimization literature with big data, is used to solve the proposed model  

Transportation is an essential part of the economic growth in every country in the nowadays industrial era by making the possibility of good’s consuming, far from its origin. Delivery of a final product to the customer’s needs transportation of raw materials from suppliers to producers, transportation of semi-final products between companies, and, finally, delivery of the final product to customers and destination markets. Transportation costs include the majority of logistic expenses because of their abundance (between 30-60 percent). Traveling salesman problem and after that vehicle routing problem have been proposed about 70 years ago. In the last few decades, mathematical models, precise...