PRODUCTION AND OPERATIONS MANAGEMENT
Year:2020 | Volume:11 | Issue:1 (20)|Papers Count:8

Purpose: Long-term interaction with supplies in supply chains has nowadays become a key activity in organizations, and the companies attempt to improve their capabilities by using it. Due to the limitations of capable suppliers, ongoing technological developments, and the market's new requirements, it is necessary to develop the shortlist of each organization's suppliers, which is both time-consuming and costly. Thus, the development of suppliers' competitive capabilities is a strategy for creating shared benefits for all members. But, what is the correct position of the suppliers' development? What is its preface? This research aims to design a model for the development of the suppliers of a contractual holding company within the domain of engineering and design, production, construction, erection, and commissioning to establish sustainability in the supply chain. Therefore, by creating a model, through giving prominence to appropriate relations with each supplier, the improvement of the suppliers through the combination of qualitative and decision support models will be provided, so that all quantitative and qualitative criteria of purchase management are taken into consideration. Design/methodology/approach In this research, a process model and software for suppliers' development in the contraction field is provided employing qualitative patterns and decision support models for the sustainability of the supply chain. For this, along with the growth factors, requirements of customers, and beneficiaries in environmental; social, and economic dimensions are included. Therefore, methods such as investment, performance enhancement of key purposes, and training are used. To evaluate the suggested model, ten suppliers, qualifying the requirements of the conglomerate contractual company, are recognized and analyzed for seven months in cognitive, development-monitoring, and executive sections. The results obtained confirm the validity of the model and software in expert panels. Findings The main findings of this research are the design of a comprehensive process model and software within a sustainable development framework. In the recent model, contrary to the previous research, all different working areas of the suppliers for all contractual companies with the various buyer and seller relations have been considered inclusively. The output of this model is the plan for the integrated development and improvement of each supplier. The tracking of the improvements gained for different areas shows that, out of 39. 29 percent total improvement, 15. 99 percent is related to 40 percent of the suppliers with strategic unity. The remaining 23. 30 percent is related to other suppliers. Research limitations/implications The challenges are motivating suppliers' participation, the permission of client involvement into details, and delay of some development plans. For further research, it is suggested that the chapters of recognition instruments and the gap analysis be revised and, if necessary, the empty module of the model be completed. For the software section, the system can be developed integrally online. Practical implications Through reviewing suppliers, the development of suppliers was classified in the form of investment conglomerate company through consultation and training, persuasion, promotion of performance goals, the necessity to execute standards, and supervising their execution and legal obligations and determination of the strategies and key objectives. The other development tool was provided appropriate for any action suggested. The main barriers of improvement actions to be implemented by suppliers can be summarized as the lack of organization’ s senior managers’ support due to the informal execution of the project within a short time (seven months), and more than one-year time needed for improvement actions (i. e., the results of the actions were not achieved in monitoring section). Social implications As the development and implementation of the model are related to the sustainable supply chain, the social responsibility in each supplier is also promoted through the assessment of the indicators. For this purpose, various methods including rules implementations, following national and international standards, training and investment are used. Originality/value The novelty of this research is the development and simultaneous implementation of the three phases (assessment, development, and monitoring) in an integrated sustainable supplier development model.

Purpose: The project portfolio problem proceeds to choose a subset among the proposed projects in organization. One of the purposes of project portfolio management is the reduction of the available risks in portfolio selection process. In real world, the project risks are rarely independent, and generally have a degree of interaction. By considering this interaction the more accurate evaluation of portfolio selection can be achieved. The purpose of this study is to provide a framework for selecting project portfolios by considering the triple interaction between projects for the first time using the correlation coefficient and the theory of cross-information for the risk factors affecting them. Design/methodology/approach: First, this research identifies the most critical risks based on the literature review, project management body of knowledge and the relevant experts' opinions. Then, a questionnaire was distributed among 30 experts to quantify the identified risk criteria. The identified risks that are included 11 risks are in the categories of “ technical” , “ external” , “ organizational” and “ project management” . Then theses risks are placed in to the “ cost” , “ time” and “ quality” classification. By considering the individual project risk, the projects which their risks were higher than the allowable limit, were not able to compete in the portfolio. Also, the pairwise and triple-wise interaction of the projects based on effective criteria caused that the projects which provoke risks synergies in the portfolio to be prevented from being together. By analyzing risks, the pairwise interaction effects between projects are calculated using Spearman's correlation coefficient and for the first time the triple interaction effects between projects are calculated using theory of crossinformation to discover more precisely the effect of factors on each other. Finally, the modeling in the form of a case study based on integer linear programming along with two goals, “ maximize IRR” and “ maximize the number of projects in the portfolio” , are accurately assessed to evaluate the research validity. Findings: The problem of project portfolio is the selection of a subset of proposed projects according to the strategic goals of the organization and the associated constraints. This paper provides a framework for selecting project portfolios by considering the triple interaction between projects for the first time. The results show that considering pairwise and triple-wise interaction instead of individual pairwise interaction comprise different answers. This result leads to discovering the relationship which can not be identified just with the pairwise interaction. Research limitations/implications: In this research the risk criteria are considered generally, while, in specific projects it can be used specific criteria. Using the meta-heuristic methods when the problem dimensions are increased is another area for future research. In addition, fuzzy methods and stochastic subject in order to quantify the risk criteria could be considered. Besides, this paper considers risks with negative aspect for project portfolio selection, while, in future research suggested that the risks with aspect of the positive are considered as well. Practical implications: One of the most important application of this paper is for project-oriented companies that are involved in doing multiple projects simultaneously. The results of this paper are useful for these companies for risk reduction in selecting and performing their projects. Social implications: This paper considers the most important risks affecting project execution. These risks include external risks of organization as well as internal and technical risks of organization. So, the paper helps organizations for the most appropriate selection of projects that could have benefits for organization and also society. Originality/value: In the literature, there are various methods that researchers have considered for risk management. Most of these studies don’ t consider interactions between projects or simply they considered only pairwise interaction. The main purpose of this study is to consider a higher level of interactions that is triple interactions that not considered in the literature. The results show that considering triple-wise interaction instead of individual pairwise interaction comprise different and better results.

Purpose: Regarding urban population growth and importance of time and cost in the societies of today, subway systems have faced with demand increase and passengers waiting time have prolonged. In urban transportation systems especially in subways, the passengers waiting time influences the society satisfaction deeply. Since the emersion of rail network, time and scheduling as important challenges have been emerged. Then the periodic train planning as one of the best solutions was introduced to decrease passenger waiting time, reduce travel length, and increase transportation safety. This challenge should be solved by subway managers. Due to the limited number of trains and equipment on subway lines and increase of their cost-effectiveness in reducing passenger waiting times at intersections, an attempt has been made in this paper to reduce waiting time using optimization models that often do not impose costs on the system. In addition, another aim of this paper is to fill the existing research gap in this area. Design/methodology/approach: This paper aims to calculate the weights of intersections stations in order to minimize the passenger waiting time through goal programming (Khalili Damghani et al. 2015; Mosadeghi et al. 2010). Many studies have been done on train scheduling and transportation mathematical modelling all around the world (Moghaddam and Mahlooji, 2017; Sadeghieh and Dehnavi-Arani, 2019). The aim of this paper is to minimize the deviation from desirable situation through goal programming. The main function of the proposed model is formulated again along with new construction, auxiliary variables and optimum values. It consists of variables with the concept of “ deviation of desirable situation” . In this paper, both of the deviations of desirable situations are shown by and which are undesired and should be minimized to achieve the optimum value. For this purpose, the fourth line of Tehran subway system and its intersections sections are considered as the real world problem. Findings: The model is solved by Lingo and optimum values are calculated. The model is developed based on goal programming and it can reduce the passenger waiting time and satisfaction which results in increased acceptance of public transportation in society. These findings are compared with current values of time tables for first and last movements. Findings indicated that the proposed model can reduce the passenger current waiting time by 42%. Research limitations/implications: In this paper, the accurate amount of passenger population was determined in a day based on lines, separately. Also, it was difficult to collect study data from the Tehran subway system organization. The proposed approach resulted in reduced passenger waiting time. Suggestions for further study include examining and analyzing the factors causing train delay and comparing the results of each single line with another; using simulation method to develop an optimization model for time tabling of train movement in order to optimize energy consumption; calculating and optimizing the number of subway station staff; and optimizing models to design the subway station network. Practical implications: As Tehran public transportation system is extending to cover more urban regions, the intersection stations will increase. Therefore, the role of these stations will be more tangible. Each intersection station scheduling affects the train movements in other stations and this continues throughout the length of the network. It means that each delay and pause will influence the other intersections, increasingly. The subway system managers can employ this model on other lines and reduce the waiting time of passengers in the whole Tehran subway. Social implications: As mentioned earlier, the waiting time of passengers in different stations, especially in intersections, is an important factor in using subway system as an effective public transportation system. It will increase or decrease the rate of subway usage. More public transportation usage leads to less air pollution, less traffic and faster travels in the city, which are all desirable for society. Originality/value: In this paper, a goal programming model was proposed to minimize the deviations in the objective function and subsequently, the passenger waiting time in intersection stations. As the intersection stations are increased, the role of the proposed method can be considered as a solution for public transportation in different cities of Iran.

Purpose: Hub location problems are getting more and more attention today due to their widespread application in designing product transportation systems and communication networks. In these systems, products (including data transmission, passenger transportation, freight forwarding and logistics, postal services, etc. ) are shipped from multiple sources to multiple destinations. The performance of these systems can be improved by using hub points. In fact, instead of just deciding on a single period, a planning horizon with multiple time periods is considered. The necessity of doing this research is that decisions are made in each period according to the costs and flows of the same period. In the real world, facilities are usually depreciated after a certain period of time and must be closed or rebuilt if possible. Design/methodology/approach: In this research, hubs reconstruction is allowed, meaning it can be reconstructed to reduce costs rather than startups, to operate for a specified lifetime and to cover network demands. It is also selected to operate hubs from different contractors. In this study, there are also several levels of capacity to set up that can be selected with respect to the demand of the period, which is both sufficient and cheaper to meet the demands. Genetic algorithm has been used to solve and evaluate the model performance. In general, this study has attempted to provide comprehensive modeling for the multi-period hub location problem with multiple capacities. The investigated problem considered the hubs lifetime as well as the possibility of reconstruction at the end of lifetime. It has also been attempted to design the model to suit real-world conditions. Findings: Investigations in this study showed that the proposed model is more efficient than the previous models in terms of coordination and compliance with real-world conditions. Further, the validity of the proposed model was also evaluated by performing a variety of sensitivity analyzes. Solving the various numerical examples by the genetic algorithm and comparing them with the exact method demonstrates the acceptable performance of the meta heuristic method. Research limitations/implications: For future research and improvement of proposed model the following recommendations are suggested:  Consider different capacity levels for nodes so that the capacity of each node can be changed at different times depending on the problems conditions.  Assume that the hubs can be closed before the expiration date depending on the problems conditions.  Consider case studies in various industries and model development with conditions much closer to real situations, for example in the field of urban transport, perishable products, emergency services, and so on.  Using uncertain programming such as probabilistic and fuzzy programming to predict and plan the model and its parameters in successive periods.  Providing solution methods with better performance and solving larger problems in rational times. For example, heuristic methods can reduce the complexity of the problem and thus solve larger samples in shorter times, so they will be useful. Practical implications: The main advantage of a multi-period problem over a single period problem is making the best decision in the time frame. In the single-period model, once the decision is made for all time periods, it is obvious that this decision will not be optimal because the parameters and conditions governing the problem are not the same over successive periods, so the result will not be global optimal. Another advantage is that the single-period model optimizes the cost of each period separately and it does not consider the relationship between the network structure of the nodes in different periods. Therefore, in this study, a multi-period model was proposed to obtain the global optimal solutions. Originality/value: The main difference between this study and previous work is the following:  Providing a hub location model in which it is possible to select a contractor for each hub set up.  In this research, the hubs have a known lifespan and this lifespan is determined after the contractor selection.  Providing a new model that enables the choice between reconstructing and closing at the end of each hub's life by considering network costs.

Purpose: In today's world, cyberspace and, of course, the communication and information system in the web platform is among the most popular categories. This category has attracted the attention of various private and public sectors for various reasons, including increased productivity, increased transparency, and increased serviceability. Therefore, the purpose of this study is to improve the quality of services in the field of e-government and thus increase the efficiency of government. Design/methodology/approach: The proposed model incorporates the key measures of e-government service quality to achieve better reliability and user satisfaction of e-government services while keeping the recurring expenditure low. This model has been designed by Interpretive Structural Modeling and DEMATEL. The researchers have architected and engineered key factors of egovernment service quality and have developed an integrated model and identified the interactions among those factors. The case of this paper is the governmental kiosks as one of the main sites for delivering service. Findings: This research resulted in a model that indicates e-government service quality measurement indicators including customer confidence, efficiency, customer relationship, first time service, variety of services, service availability, service traceability, service support, interoperability, infrastructure, compensation, fit, compliance, quality assurance, and complaint management. Thus in the first step, the criteria were identified; in the second step, the criteria were categorized and designed by the opinion of experts; and finally, the intensity of the relationship among the criteria was determined to be aware of influence and effectiveness among them. Research limitations/implications: Design mechanisms to monitor advances in technology and egovernment to improve the proposed model and update the model are the most important suggestions. Another suggestion is identifying the gap between the theoretical developed model and practice. Practical implications: The implication of this study is to achieve improved quality and to reduce the cost from lack of knowledge of qualitative criteria, mapping key indicators within the framework of a scientific model to improve the quality of e-government services while missing key policymakers and practitioners. Implementing this model in practice can satisfy electronic service providers by applying a part of indicators such as efficiency, interoperability, and infrastructure and satisfy the receiver of services by another part of indicators such as quality assurance, first time service, and complaint management. As a result, if the model is fully implemented, it will satisfy both the service provider, and the customer. Social implications: Reducing the gap between the people and the government and thus increasing public satisfaction is the most important achievement of this research. In addition, transparency, which is a very important issue, can be addressed in the context of the web. Thus, e-government can result in transparency and satisfaction. Originality/value: Because no established mapping model for governmental kiosks has been provided for effective, low-cost, high-quality e-government service systems, the proposed mapping model closes this gap and provides guidelines to evaluate e-government services. The paper provides appropriate tools both to practitioners and policymakers who work with information and communication systems.

Purpose: Suppliers, as one of the vital partners of the supply chain, contribute to creating a sustainable supply chain. Also, resilient supplier selection can help to reduce the severity of the disruptions' effects. Thus, the simultaneous application of the sustainability and resilience principles in the process of supplier selection and order allocation plays a significant role in achieving sustainability and continuity of business processes in the occurrence of disruptions. This study aims to select a set of sustainable and resilient suppliers and to allocate demand in an automotive supply chain under disruption risks. Design/methodology/approach: In this research, a hybrid approach has been presented for evaluating and ranking suppliers based on sustainability criteria and modeling the problem of selecting a sustainable-resilient supplier and order allocation under disruption risks. VIKOR (Vlse Kriterijumska Optimizacija Kompromisno Resenje which means multi-criteria optimization and compromise solution, in Serbian) as a multi-criteria decision-making technique has been used to determine the sustainability score of suppliers and the results have been considered as the input parameter for the mathematical model. The proposed mathematical model is two-stage stochastic programming to minimize total cost and maximizing sustainability performance in the case of disruptions, which is solved using the Ɛ-constraint method. Multiple sourcing and flexibility in the production capacity of suppliers have been considered as effective strategies to reduce the severity of disruptions. Iran-Khodro supply chain data has been also used to validate the research model. Finally, sensitivity analysis has been performed to investigate the effects of parameters' change on the final results. Findings: The results indicated that by increasing the importance coefficient of sustainability performance in the supply chain, the overall value of the supply process increases during disruptions, and multiple sourcing and the use of suppliers' flexible capacity are effective strategies in reducing the severity of disruptions. Also, examining the effect of reliability on the expected cost indicates that the occurrence probability of disruption risk in suppliers can affect the total cost of the procurement process and can also reduce the sustainability goals. Research limitations/implications: In this research, the effect of disruption risk has been examined. As a subject of future study, the operational risk is suggested to be recognized in the supplier selection problem. Besides, unique events have been considered in the model of this research. In the future, semi-super and super events can be also studied. Finally, using other resilience strategies in supplier selection problem such as adopting backup suppliers, protecting suppliers, and pre-positioning inventory can be a potential direction for future research. Practical implications: The company under study can consider the results of the presented model and focus on utilizing suppliers' flexible capacity, multiple sourcing instead of single sourcing of parts, partially. Given the importance of sustainable development, particularly in automotive supply chains, it is essential to consider the sustainability performance of suppliers in sourcing decisions with disruption risk in addition to cost and reliability criteria. Thus, the company can evaluate the suppliers' sustainable performance in the occurrence of disruption to achieve sustainable development and business continuity and to meet the needs of stakeholders. Social implications: Due to the subject of this study, i. e. sustainable supplier selection in the resilient supply chain, the performance of each supplier has been evaluated based on social and environmental criteria to consider social responsibility and environmental issues in the sourcing decisions under disruption risk. Originality/value: A few studies have taken into account the dimensions of sustainability and supplier risk simultaneously in the field of supplier selection and demand allocation. Flexibility in the supply capacity of the supplier, as an effective resilience strategy, and economic criteria such as C/100 index, PPM production line, payday resistance, communication system, etc. have not been studied in the literature of sustainable and resilient supplier selection.