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    A Multi-Objective Robust Optimization Model for Logistics Planning in the Earthquake Response Phase [electronic resource]

    , Article Transportation Research Part E: Logistics and Transportation Review, Elsevier ; Volume 49, Issue 1, January 2013, , Pages 217–249 Najafi, M. (Mehdi) ; Eshghi, Kourosh ; Dullaert, Wout ; Sharif University of Technology
    Abstract
    Usually, resources are short in supply when earthquakes occur. In such emergency situations, disaster relief organizations must use these scarce resources efficiently to achieve the best possible emergency relief. This paper therefore proposes a multi-objective, multi-mode, multi-commodity, and multi-period stochastic model to manage the logistics of both commodities and injured people in the earthquake response. Also, a robust approach is developed and used to make sure that the distribution plan performs well under the various situations that can follow an earthquake. Afterwards, it proposes a solution methodology according to hierarchical objective functions and uses it to illustrate the... 

    An Approach to Optimize Resource Allocation and Strategies to Control Infectious Diseases

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Ahmad (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Infectious diseases have always been a threat to mankind, and is the greatest causes of death of children and young people. Although this type of diseases is a serious threat to public health; the allocated resources in responding to a semi-large pandemic is inadequate. Therefore, it is important to spend the resources in the most effective and efficient ways to improve pandemic response capability. That is why considerable research be devoted to study different aspects of epidemics, and developed mathematical approaches to choose appropriate strategies in pandemic response. Since the epidemic models are simplified means to describe the transmission of disease, researchers often use these... 

    Designing a Mathematical Model for Optimizing Organ Transplant Network

    , M.Sc. Thesis Sharif University of Technology Poursaeed, Alireza (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Presently, numerous patients die each day while they are awaiting life-saving organ transplant. Despite advances in medicine and technology, and increased awareness of organ donation and transplantation, the gap between supply and demand continues to widen. Therefore, appropriate utilization of donated organs under organ allocation process is vital, and can save several patients’ life. Due to this cause, this study presents a mixed integer multi-period mathematical model to optimize allocation system in an organ transplantation network. The considered network includes donors, hospitals, procurement centers, transplant centers, and patients. The proposed model strives to minimize the overall... 

    Blood Inventory Management in Hospitals: Considering the Uncertainty
    of Supply, Demand and Blood Transshipment

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Ali (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    In recent years there is a growing trend in designing efficient health care systems. The applications of operations research have been instrumental in advancing this growing trend too. The blood management issue has raised concerns for human on the other hand. Blood is one of the vital commodities in the field of health. Despite significant advances in the field of medicine, a suitable replacement for this vital commodity has not been found yet. Collecting and managing the distribution of blood that is discussed in the blood supply chain management, requires careful planning and managing. In this research blood inventory management in hospitals considering the uncertainty of supply, demand... 

    A Model to Schedule Hospital Nurses Considering Nurses Preferences

    , M.Sc. Thesis Sharif University of Technology Pourmohsen, Rokhsareh (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    The nurse scheduling problem is an inevitable issue in managing of hospital wards. Maintaining high quality of working in hospitals is too difficult in tense and high-pressure work environment. Manually solving the scheduling problem is time-consuming. It can pose problems to considering individual excellence, personnel requests and distributing shifts in a fair and desirable manner. These problems and the impossibility of considering all conditions together made the nurse scheduling as an important scheduling problem. In this research we propose a model to assign nurses to shifts considering regulations and hospital’s policies. Unlike nurse scheduling literature we consider nurses... 

    Developing a Continuous Location Routing Model and Providing a Hybrid Algorithm Based on Automatic Clustering

    , M.Sc. Thesis Sharif University of Technology Sarabi, Ali (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Generally, the costs of logistics and distribution are included in the significant share of the product price. Hence, choosing appropriate decisions and reducing these costs can have an important effect in reducing the price of products and services, increasing the competitiveness of enterprises. One of the most important measures, in order to achieve this goal, is to integrate location of distribution centers and the routing paths of goods. That how these decisions are made in the networks and discrete problems seriously has been taken into consideration but in continuous areas due to the complexity has not been studied a lot by scholars. In this study, we try to develop a model for... 

    An Approach to Optimize Beam Angles and Fluence Map in IMRT

    , M.Sc. Thesis Sharif University of Technology Faridmehr, Mahsa (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Intensity Modulated Radiation Therapy is one of the most commonly used procedures of delivering radiation to cancerous tissues, with the aim of reaching the prescripted dose in the target volume while minimizing damage to nearby healthy organs. Two decisions are of fundamental importance: to select the beam angles and calculate the beam intensities. Beam Angle selection (Beam Angle Optimization) is an important problem. Due to the large amounts of computational time, beam angles are often selected manually based on human experience and intuition. In this study, three optimization methods –Simulated Annealing, Branch & Prune and Local Neighborhood Search- that are selected among known methods... 

    A Mathematical Model to Make Decision in a Combinatorial Reverse Auction Considering Lack of Supply Risk

    , M.Sc. Thesis Sharif University of Technology Farnia, Farbod (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Considering the increased variety of products or services demanded by customers, the lifetime of the products or services demanded has been shortened. So, organizations should provide the products or services they need in the shortest possible time. That is why to survive in the competitive environment created, many organizations provide the products or services they need from outside the organization to meet their customers' demand in the shortest time. One of the ways by which various products or services can be provided is to hold combinatorial reverse auctions. Following a comprehensive review of the literature related to the combinatorial reverse auctions, this study has presented a... 

    A Mathematical Model to Interdict Illegal Product Flows in the Network under Uncertainty

    , M.Sc. Thesis Sharif University of Technology Asadi, Fatemeh (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Given that drug use is rising dramatically, drug-dealing coping forces must deal with this social pest with the right planning and taking into account time and budget constraints. In line with the importance of this issue in preventing the distribution of narcotics, in this thesis a dynamic planning methodology for boycotting the most multi-commodity flow considering the uncertainty in the results of the measures has been considered. Finally, we are looking to arrest the main distributors of drugs on the network and remove them from the drug distribution network. In order to solve this problem, and taking into account the real world constraints, a dual-level model with a minimum-objective... 

    A Mathematical Model for Pricing and Container Repositioning in a Competitive Transportation Network

    , M.Sc. Thesis Sharif University of Technology Soleimani, Mahdi (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    The transportation is one of the important components in the economies of different countries. In the maritime transportation network, the demand is usually not balanced in different routes, and this imbalance results to accumulation of containers in a node. In order to sustain the problem, firms have to reposition empty equipment from a surplus location to a shortage location, which causes the problem of “Empty Repositioning Problem”. In this study, pricing strategies in one transportation market with two locations are considered; while there is ERP problem in issue. The problem is solved by Bertrand game method. The research is divided into two parts of the monopoly network and the duopoly... 

    An Approach to Align Business Process with Business Strategies

    , M.Sc. Thesis Sharif University of Technology Shumaly, Sajad (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Todays, organizations are in a competitive global environment. Therefore, strategic planning followed by strategy implementation is critical for business success more than ever. The ability of organizations to implement strategies is important and useful for the organization’s success in the market and gives them a competitive advantage. Implementation is the process of turning strategies and plans into action in order to accomplish strategic objectives and goals. This research suggests an approach to align business processes with organizational strategies. This approach intends on managing processes based on using resources to achieve goals. The proposed model consists of three cycles which... 

    Sustainability in Supply Chain with Key Performance Indicators

    , M.Sc. Thesis Sharif University of Technology Yazdani, Omid (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Background: Sustainability is one of the most controversial issues in companies’ supply chain these days. Moreover, growing environmental, social, and ethical concerns have scrambled up the push of organizations to adopt sustainable business enforcement into their operations.Purpose: The aim of the study was to examine the current status of sustainability of supply chains and how it is measured. The goal of this study is to answer the research question: How organizations measure their sustainable supply chain performance with Key Performance Indicators? Method: To comprehensively answer the research question, a qualitative research approach was chosen, and the primary empirical data was... 

    Hospital Process Management in order to Reduce the Hospitalization Time

    , M.Sc. Thesis Sharif University of Technology Rahbarirad, Shabnam (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Health care is one of the basic needs of humankind, and meeting this important need is the responsibility of hospitals. Public hospitals, as the costliest operating units of the health care system, have always faced limited resources. Therefore, efficient use of resources, such as admission beds as undeniable necessities, could be used as an effective approach to meet the growing demand of patients, use health center capacities optimally, and reduce costs. To this end, in this research, a hospital process management approach is used to improve the utilization of hospital admission beds as a valuable resource, and reduce the false bed occupancy rate in Shohada-e-Tajrish University Hospital... 

    A Mathematical Model to Investigate the Advantages of Participation of the Compatible Pairs in Kidney Exchange Programs

    , M.Sc. Thesis Sharif University of Technology Abbasi, Mohammad Hossein (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    In the current situation, kidney transplantation is the most appropriate and least costly treatment for patients with end-stage renal disease (ESRD). Related or altruistic living donors, as well as deceased donors, are considered as a supply source for donated kidneys. Researches have shown deceased donor kidney may not work as well as a living donor kidney because the deceased donor kidney is outside the donor's body for a longer time. If the donor has an incompatibility with the patient (in terms of the blood group, HLA, etc.), a kidney exchange between the pairs can be used to resolve the issue and make the transplantation possible. Pairs with blood group compatibility have also... 

    A Mathematical Model to Apportion the Cost of Kidney Purchasing in Domino-paired Donation

    , M.Sc. Thesis Sharif University of Technology Hosseinzadeh, Arian (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    The human body normally has two functioning kidneys, while only one of them is sufficient to have a healthy life. However, for those patients having no functioning kidney, transplantation is the most effective treatment. Although deceased donors have been usually used as the main source for kidney donation in many countries, there are several cases focusing on living kidney donation to compensate for the shortage in supply and to reduce the patient waiting time for treatment. Because of this potential, many studies have been conducted to optimize the non-clinical issues of kidney transplant waiting lists. Notwithstanding employing the financial incentives for living kidney donation is... 

    A Mathematical Model to Locate Multi-Level Multi-Service Health Facility Under Uncertainty

    , M.Sc. Thesis Sharif University of Technology Motallebi Nasrabadi, Alireza (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    In this study, a mathematical model for health-care facility location in two level and multi-services has been described. The facilities has two levels of clinic and hospital that has inclusive hierarchy property. In clinics, only outpatient services delivered. But, in hospitals in addition to handle outpatient services, inpatient services and emergency services are provided. In this research, we practice on queuing theory in order to consider the serious uncertainties in the health service, for instance, random demand and random service time, and by the help of which the criteria for considering the service level is calculated. Then by using applicable change variable and service level... 

    After-sales Service Pricing in a Two-echelon Supply Chain

    , M.Sc. Thesis Sharif University of Technology Ghayouri Pirsolton, Sepideh (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    The present study proposes a pricing model for manufacturing and customer support companies which is carried out in the form of multi-level programming. In this model, the manufacturer is considered as the leader and supporting companies as followers. In fact, manufacturer sets up the price level for its customer support first and then according to this price level, customer support companies choose their products and specify the level of after-sales services and the prices. The purpose of this study is to provide insight into the analysis of the after-sales services in a supply chain. The results can be notable for managers in order to demonstrate the impact of different strategies of... 

    A Model to Integrate Supply and Production in a Sustainable Supply Chain

    , M.Sc. Thesis Sharif University of Technology Pourmohammad Reza, Nima (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Financial benefits are no longer the only decision makers’ criteria and they consider environmental and social merits due to the modern nature of management and international competing. As a result, sustainable supply chain management (SSCM) rises noticeably in popularity among academics for researching on it and industrialists for applying it. Having reviewed respective researches, The SSCM is addressed by an integrated approach in this rsearch for selecting green suppliers and finding optimal production plan in two phase. In first phase, thank to related literature, a framework including environmental criteria is purposed for evaluating suppliers by Analytic network process method (ANP).... 

    A Mathematical Model to Consider Uncertainty in IMRT Treatment Planning

    , M.Sc. Thesis Sharif University of Technology Amini Zadeh Zare, Monireh (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    Intensity Modulated Radiation Therapy is one of the common methods for treating cancer patients because of the ability to transfer high doses of radiation to the tumor and minimize damage to surrounding healthy organs. In this method, the patient is placed in a special bed, while a linear accelerator directs the beams to radiation to the target's size. Patient treatment requires a unique treatment plan, and optimization of the treatment plan involves two basic decisions: (1) selecting the beam angles; (2) calculating the beams intensity. In the radiation therapy process, there are various uncertainty factors, such as patient setup, tumor volume definition, tumor growth or movement, and the... 

    Optimization of Combination Chemotherapy Problem with Uncertain Cell Cxycle

    , M.Sc. Thesis Sharif University of Technology Jafari, Ali (Author) ; Rafiee, Majid (Supervisor) ; Najafi, Mehdi (Supervisor)
    Abstract
    Nowadays, chemotherapy is one of the common ways to treat cancer. Although, chemotherapy is used to kill cancer cells , chemotherapy drugs also target healthy cells and tissues of the body. In practice, it is difficult to strike a balance between injectable doses of drugs and toxicity in the body, and physicians are always looking for an effective treatment plan. One of the most common drugs that physicians use in chemotherapy is cell-cycle-specific drugs. These types of chemotherapy drugs affect only a certain phase of cell cycle and to a certain extent. Since the lifetime of the cancer cells is uncertain, the effective use of these drugs depends on the correct injection time of the drugs...