Neda Manavizadeh; soroush aghamohamadi-bosjin; Parisa Karimi-Ashtiani
Abstract
This paper proposes a bi-objective model for the waste collection problem and considers the location, routing and inventory of the system simultaneously. Considering the reverse flow of the system is another feature of the current study. In the proposed model, the total costs of the system are minimized. ...
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This paper proposes a bi-objective model for the waste collection problem and considers the location, routing and inventory of the system simultaneously. Considering the reverse flow of the system is another feature of the current study. In the proposed model, the total costs of the system are minimized. In addition, the related risks of opening new centers and transportaion are included as the second objective function of the problem. Considering the delivery time and cpacity of vehicels constraints, are the other features of the model. Due to the NP-hardness of the model, two metaheuristic algorithms namely a non dominated sort ordering genetic algorithm (NSGA-II) and a multi objective particle swarm optimization algorithm (MOPSO) are applied to solve the problem. According to the results, NSGA-II is able to reach better answers in all the propsed metrics. According to sesitivity analysis, foreign transportation fleets make a great impact on the costs of the system.
production and operations management
Mahsa Sobhi shojaa; Parvaneh Samouei
Abstract
In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely ...
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In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely employed in many industries due to their efficiency and flexibility . In these lines, a worker can be assigned to multiple stations located at entrance and exit sides. However, in many realistic situations, robots may be unavailable during the scheduling horizon for different reasons, such as breakdowns. This research deals with line balancing under uncertainty The Objective in this research is minimizing the cycle time for a given number of workstations and minimizing robot cost.This research deals with line balancing under uncertainty and presents one robust optimization model for balancing and sequencing of u-shaped robotic assembly line with considering set up times between task, failure robot times and preventive maintenance times for every robot. Since the NP-hard nature of the problem, multi-objective harmony search is developed to solve it. Numerical experiments also demonstrated that by increasing uncertainty level, the objective function values, cost and cycle times (minimum, maximum and average) increased. performance of the robust approach by the results, shows that in real conditions, considering the probability of event failure, values of cycle time and cost change significantly, which indicates the need to consider uncertainty, especially failure in robotic assembly lines.
Mahdi Haghighi Kaffash; Zhre Dehdashtishahrokh; Vahid Khashei; Reza Hajari
Abstract
This study is conducted to identify and analysis the relationship between the factors affecting the distribution network design (DND) in the food distribution industry in Iran. In this paper, the distribution network design has been classified into two main areas of the strategic structure of the distribution ...
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This study is conducted to identify and analysis the relationship between the factors affecting the distribution network design (DND) in the food distribution industry in Iran. In this paper, the distribution network design has been classified into two main areas of the strategic structure of the distribution network and the distribution management policies and the impact of the key variables on distribution network design has been investigated. This study is descriptive, exploratory and using quantitative research method. The statistical population of this research is all 54 food distribution companies in Iran. Using a census method, a questionnaire was sent to all general and marketing managers of these companies (108 people). 92 questionnaires were completed, according to the established criteria, only 81 questionnaires could be used, which also covers the standards of Cochran formula. The partial least squares (PLS) method is used to analyze the data and the results show that product characteristics, service requirements, demand characteristics, supply characteristics, and economic variables are the key variables that affect the distribution network design. Given the lack of research on the distribution network design and the study of the factors affecting the formation of strategic distribution structures and policies, it can be argued that this article provides valuable insights for academics and professionals, because in many studies the various components of distribution network design, the decisions related to the design of the distribution network and the analysis of the main factors affecting the distribution network structure are presented
Azam Tariyan; Hessam ZandHessami; Abbas khamseh
Abstract
The construction industry has always had significant destructive effects on the environment. Utilizing green supply chain management strategies to achieve sustainable construction is an effective approach to reducing environmental damage. In this research, the qualitative approach and interpretive paradigm, ...
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The construction industry has always had significant destructive effects on the environment. Utilizing green supply chain management strategies to achieve sustainable construction is an effective approach to reducing environmental damage. In this research, the qualitative approach and interpretive paradigm, along with the seven-step meta-synthesis method, were employed to explain the influential components in establishing green supply chain management in the construction industry. A total of 728 relevant studies in the field of supply chain management, particularly with a focus on sustainability, green practices, and reverse logistics, were identified, reviewed, evaluated, and screened. Based on the entry and exit protocol, 37 studies were included in the research portfolio, resulting in the extraction of 73 primary codes that were categorized into 13 concepts and 4 categories. The reliability of the classification was confirmed using the Kappa coefficient. The research findings revealed that the components influencing green supply chain management were identified across four main categories: main factors of green supply chain management, facilitating factors, internal and external drivers and barriers. Finally, suggestions based on the extracted results from this research were presented for future researchers. IntroductionThe construction industry is the primary consumer of resources and energy worldwide and has significant detrimental effects on the environment. Environmental protection and sustainability have become global concerns across various industries in the past two decades. Companies and governments in many countries are recognizing the importance of green supply chains, and this awareness is rapidly growing within the construction industry. Currently, competition between companies has shifted towards competition between their supply chains. Therefore, expanding the concept of sustainability in supply chain management is considered a strategy to enhance performance and improve a company's competitiveness. Green supply chain management is highly regarded among academics and industry professionals as it aims to preserve product quality, conserve resources, and minimize production waste. In the construction industry, green supply chain management involves managing all activities throughout the supply chain that contribute to the final product (building) to minimize environmental impacts. Hence, a holistic approach is required to manage all construction project activities and ensure sustainability across social, economic, and environmental dimensions. While extensive studies have been conducted on green supply chain management in various industries, the number of studies in the construction industry is relatively limited and fragmented, lacking a cohesive understanding of scientific findings in this field. To address this research gap and considering the importance of the topic and the lack of a comprehensive method in this field, the current research aims to present a model and identify the factors influencing green supply chain management in the construction industry, particularly in Iran. Materials and MethodsAccording to the nature of the research, the current study adopts a meta-synthesis approach, which is qualitative in nature with an interpretive paradigm. Meta-synthesis is a type of systematic qualitative approach that combines and integrates qualitative findings from different but related studies. By providing a systematic perspective to researchers, meta-synthesis allows for the discovery of new and fundamental themes and insights by synthesizing various qualitative studies. This approach enhances the existing knowledge and provides a broader understanding of the issues at hand. The seven-step method developed by Sandelowski has been employed to conduct the meta-synthesis. The data collected for this research have been coded and summarized using content analysis with the assistance of the MAXQDA qualitative data analysis software.ConclusionsThis research aimed to identify the factors influencing green supply chain management in the construction industry. After conducting keyword searches, the identified documents were screened and evaluated, resulting in a set of documents that were coded and summarized using content analysis. These codes were then evaluated by experts. The findings were categorized and presented in a table, and a visual model was proposed for better comprehension. The research findings revealed four categories of factors influencing green supply chain management: main factors, facilitating factors, internal and external drivers, and barriers. The main factors identified in this research include green purchasing, green design, green construction, and reverse logistics. Facilitating factors include human resource management, green technology, internal environmental management, and green marketing. Additionally, the research identified important drivers and barriers for the implementation of green supply chain management. Internal drivers include the desire to enhance reputation, credibility, and business image; cost reduction; the desire to enter foreign markets; and societal pressure
Ebrahim Alimohammadi As; Alireza Bafandeh Zendeh; Houshang Taghizadeh
Abstract
The study aims to simulate the strategies of Islamic Azad University (Tabriz branch) during 2019- 2034 period through system dynamics approach. Based on research literature, student trend, physical resources, educational quality, human resources, research and publication and financial operation were ...
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The study aims to simulate the strategies of Islamic Azad University (Tabriz branch) during 2019- 2034 period through system dynamics approach. Based on research literature, student trend, physical resources, educational quality, human resources, research and publication and financial operation were considered as key effective variables in formulating the strategies. By using reliable theories in the field of problem-solving literature and experts' opinion, causal relations between variables have defined in the form of mathematical functions and finally simulated has been done. The scenarios were formulated and analyzed based on three main objectives, namely cost reduction, increase of revenue and educational quality development. Results show that by the implementation of downsizing scenario in Tabriz Azad University, the tuition rate of the university experienced a decrease of five percent. The second scenario show that if research budget experiences a change of 40%, non-fee revenues would grow 19%. The simulation of the third scenario revealed that, 25% increment of new investments in Tabriz Azad University leads to the growth of student attraction rate by 17% in long term. By considering results of three scenarios we could suggest that Tabriz Azad University should follow the two strategies of increasing research budget and making use of new investments.
Seied davoud Mirhabibi; Hasan Frsijani; Mahmoud Modiri; Kaveh Kahlili-Damghani
Abstract
Today, the organization and industries are facing with global competition. Organizations should manufacture their products in a world class level to become successful in global competition and they have to be more integrated at the level of organization partners as well as supply chain. In this article, ...
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Today, the organization and industries are facing with global competition. Organizations should manufacture their products in a world class level to become successful in global competition and they have to be more integrated at the level of organization partners as well as supply chain. In this article, World Class Manufacturing (WCM) factors have been identified by using fuzzy Delphi Method. Dimensions and components related to integrated supply chain have also been extracted from subject literatures. They include: internal integration, supplier integration and customer integration. Importance Performance Analysis (IPA) has been used to categorize and characterize the priorities related to improvement of supply chain integration (SCI) for achieving (WCM). We used opinions of 200 experts comprising managers and politicians of Iranian domestic appliance industry as well as research final model to identify optimal strategies for managing all factors. According to the outputs of IPA matrix, final ranking of all SCI factors were identified to help managers optimally allocate resources. Results show that having stable purchasing system with main suppliers, integrated system among internal departments, level of sharing information with suppliers and information sharing systems with customers are all considered as the most important factors to improve SCI for achieving WCM in the selected industry
Seyed Mohammad Hasheminejad; Eehsan Mhammadian Amiri
Abstract
Nowadays, managers in the public and private sectors consider having knowledge of green laws and issues are essential in surviving of their organizations. Although researchers have promoted each issue of green human resource management and green supply chain management separately, but there has been ...
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Nowadays, managers in the public and private sectors consider having knowledge of green laws and issues are essential in surviving of their organizations. Although researchers have promoted each issue of green human resource management and green supply chain management separately, but there has been a great delay in integrating these two issues. Therefore, this study first attempts to provide an integrated and coherent framework for linking green human resource management and green supply chain management (GHRM-GSCM). For this purpose, firstly, using a comprehensive literature review of the research, interviews and expert opinion on the ornamental industry, the initial identification of evaluation indicators in green supply chain management and green human resources management was undertaken. In the next step, the causal relations were determined by using the fuzzy DEMATEL method and the weight of each of the criteria and sub-criteria were determined with the fuzzy ANP method. The results of this assessment show leadership, flexibility, and environmental factors based on their importance are identified as effective factors, and optimizing these factors by the Arya array industry could lead to other factors optimization (influencing factors).
Omid Abdolazimi; Marzieh Khakestari
Abstract
One of the important techniques in the field of inventory management is inventory classification. ABC analysis is a well-known method which sets the items in a different class, according to their importance and values. In this paper, a three-level supply chain network for a bio-objective optimization ...
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One of the important techniques in the field of inventory management is inventory classification. ABC analysis is a well-known method which sets the items in a different class, according to their importance and values. In this paper, a three-level supply chain network for a bio-objective optimization model is proposed to improve the quality of inventory grouping based on ABC technique. The first objective maximizes the net profit of the items in the central stock (level 2) and the second objective function maximizes the net profit of items in different wards (level 3) in uncertain condition. The proposed model simultaneously optimizes the service level, the number of inventory groups, and the assigned items to each group based on the set of constraints, inventory shortages, ordering cost, and purchasing cost. To solve this model, the heuristic and exact methods such as LP-metric and modified ε-constraint are applied. Then for comparing those methods, the statistical hypothesis test is used. In conjunction with, the AHP technique is exerted to choose the most efficient solving method. The results show that ε-constraint has the best performance. Ultimately, the proposed model has been implemented in one set of numerical examples to show its applicability in practice.
Mehdi Yazdani
Abstract
This paper deals with the problem of two-stage assembly flow shop scheduling with considering sequence-independent setup times .The objective is to minimize totalcompletion times of all orders. In this problem, there are several orders for one type of product. Each ordered product is formed of several ...
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This paper deals with the problem of two-stage assembly flow shop scheduling with considering sequence-independent setup times .The objective is to minimize totalcompletion times of all orders. In this problem, there are several orders for one type of product. Each ordered product is formed of several different parts. At first, the parts are manufactured in a flow shop stage with some different machines and then they are assembled into a final product on a single machine. This paper presents three meta-heuristic algorithms, namely Parallel Variable Neighborhood Search (PVN) Artificial Immune Algorithm (AIA) and Simulated Annealing (SA), for solving under studied problem. The Taguchi experimental design method as an optimization technique is employed to tune different parameters and operators of presented algorithms. Also, Numerical experiments are used to evaluate the performance of the proposed algorithms. The results show that the PVNS algorithm performs better than the other algorithms
Vahid Baradaran; Armaghan Azarikhah
Abstract
The development of a variety of public transportation systems that cover different areas, has made it difficult for passengers and users to choose the type of transportation system and appropriate route between two specified departures. In large cities such as Tehran, a network of public transportation ...
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The development of a variety of public transportation systems that cover different areas, has made it difficult for passengers and users to choose the type of transportation system and appropriate route between two specified departures. In large cities such as Tehran, a network of public transportation systems, called multi-modal systems, are consist of stations as nodes and public transport vehicles intermediate between the two consecutive stations as arcs. Travelers are looking continuously for a way to find the optimal route in complex multi-modal transportation networks to reach their desired destination with minimal cost and confusion. In this paper, a multi-objective programming model with three objective functions has been developed for routing in multi-modal transport systems. The objectives of the proposed model are to minimize the cost, travel time and the number of vehicle types. By examining the validation of models by test issues, two exact and meta-heuristic algorithms (ant colony algorithm) have been developed to solve the proposed model. The results show that problem solving by exact method for networks with more than 15 nodes are non-operating, while the meta-heuristic algorithm provides the same problems with same precision in the exact method but with logical time.
