nasser motahari farimani

One of the novel approaches in supply chain management is Vendor-managed inventory (VMI). The aim of this policy is to establish a long-term relationship between retailers and vendors. The prerequisite for the long-term relationship of vendors with retailers is to select retailers who can meet the most criteria from the vendors' perspective and have a considerable level of reliability. In this paper, a two-tier supply chain with multiple retailers and multiple vendors has been developed using a combination of multi-criteria decision-making methods and multi-objective programming under the VMI policy. The developed model is such that, in order to establish long-term relationships and reduce supply chain costs, each retailer can only participate with one vendor. In general, the aim of the present study is to minimize costs, increase the reliability of retailers, and select retailers who have relative prominence compared to other retailers. To this end, a            hierarchical analysis process (AHP) has been performed for each vendor, and the weights of retailers relative to the suppliers have been calculated. Then, the obtained weights were input into the three-objective model designed. The proposed model, considering a combination of qualitative and quantitative criteria in selecting retailers under VMI, can find a combination of the best      retailers by balancing between the criteria. In order to maintain the long-term relationship of the vendor with the retailers, it is better for the vendor to consider important criteria that are  necessary in selecting retailers.

One of the most common and successful approaches to integrated supply chain management is vendor-managed Inventory. In this policy, a vendor takes control of inventory decisions for a number of retailers. This research aims to examine planning for supply, production, and distribution with an integrated approach to reduce waste and shortages of perishable products in a manner that minimizes costs for both the vendor and retailers in the supply chain, considering the vendor-managed Inventory. Since reducing the costs of waste, shortages, production, and storage of perishable goods is of paramount importance, this research simultaneously investigates the proposed model. In this study, as demand depends on product quality and quality information is not available to the retailer before production, demand follows a random and specific distribution. Since chance constraint programming has been introduced as a powerful tool for decision-making systems, in this study, the problem is modeled using this technique. Ultimately, the effectiveness of the proposed method was validated through a case study of a food supply chain. The results indicated that reducing confidence intervals in stochastic constraints could significantly reduce costs within the organization. This research can provide valuable assistance to managers when reducing waste, shortages, and demand fulfillment is of utmost importance.

One of the main obstacles to the adoption of blockchain is the cost of its adoption. The application of this technology in an organization requires the costs of development, design, maintenance, hardware, software, and energy consumption according to its adoption rate. This study uses system dynamics (SD) and machine learning (ML) methods to predict the final cost of blockchain implementation. Compared to mathematical programming, simulation techniques for estimating costs are scarce. However, SD modeling is suitable to account for the complexity and dynamic of systems and support long-term, strategic decision-making. To better understand the system behavior, it is necessary to formulate the relationships between the variables and simulate the values of the variables over time. The relationship between these variables is analyzed using the qualitative SD modeling method with stakeholders through questionnaires and 15 interviews. After identifying the variables, their effect on each other and the implementation cost are investigated. Since the charts obtained from the SD give us the behavior of state and flow variables for time, linear regression applying cross-validation, as one of the ML methods, is used to get a graph showing the system's state as a rate function. Thus, this research provides a reasonable basis for estimating the cost function of blockchain implementation. The validity of the suggested method's results is investigated through sensitivity analysis. The results demonstrate the effectiveness of the proposed model. Simulation results indicate that implementing scenarios such as changes in the average block creation time significantly enhances transaction cost, hardware cost, and software cost, leading to increased implementation cost of blockchain for organizations. The results of this research can significantly help decision-makers develop and apply blockchain technology in organizations.

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.

Supplier selection of urban train signaling equipment is one of the main problems in urban railways due to the serious impact of this equipment on the safety of travelers. The supplier's selection is a multi-criteria decision-making (MCDM) problem, in which the preferences over criteria are highly dependent on the opinions of decision-makers (DMs). The focus of the present study is to provide an appropriate model of multi-criteria group decision making in a probabilistic setting to effectively combine DMs' judgments. For this purpose, the Bayesian hierarchical model with the best-worst method (BWM) is used to determine the weights of criteria and the Vise Keriterijumska Optimizacija I Kompromisno Resenje (VIKOR) is used to prioritize suppliers. Bayesian BWM aggregates the opinions of all DMs at once, instead of averaging the individual opinions of the DMs that underlie MCDM methods. In this method, the probability of preference of one criterion over one another is calculated using Markov-chain Monte Carlo (MCMC), in addition to the weight of criteria, so that the confidence between pairs of criteria is revealed and ranking of criteria become more certain. Given that the average obtained confidence levels are 0.95, the validity of the Bayesian BWM results is confirmed. For different values of the VIKOR parameter, the third supplier will have the highest rating and the fifth supplier will have the lowest rating. The introduced multi-criteria decision model in this research will help the decision-makers of the urban railway company and other organizations with several suppliers to be able to select the best supplier by considering the relevant criteria.

In evaluating projects, there are many qualitative criteria, weighting, and quantifying, which have no definitive nature and are associated with various ambiguities. Also, because of the relationship between these conflicting criteria (goals), no single and multip optimal solutions (non-dominant set) should be sought. Because of the relationship between these inconsistent criteria (goals), no single and multiple optimal solutions (non-dominant set) should be sought. Accordingly, this study aims to provide an appropriate approach to develop a model for selecting construction projects in the public sector based on a mathematical multi-objective fuzzy model, which can cover the multi-objective nature of the problem and consider inherent inaccuracies and problem uncertainties. This paper first converts the model to a non-linear model by fractional planning concepts, defuzzification according to Jimenez and Yang approaches, then solves by a non-dominated sorting genetic algorithm (NSGA-II) to provide a more comprehensive model for governmental project selection public when allocating budget. This paper is attempted to develop a new model for selecting construction projects while considering the uncertainty of parameters using fuzzy theory in the public sector to show the performance of the developed model. The fuzzy model solution is compared with the deterministic model to analyze the results. The results show the improvements reflect the success rate of accomplishment for the corresponding goals in the fuzzy model compared to the exact one.

Hospitals are the most important component of the health system and accurate evaluation of their performance is important. So far, much research has been done on the evaluation of hospitals using DEA models, but in these studies, organizations are considered as a black box and system processes and relationships between them are ignored. In this study, the efficiency of hospitals was evaluated using network envelopment analysis and its results were compared with simple envelopment analysis.

The method of the present research was ptactical and the nature of the survey was descriptive. The research population was all hospitals and educational centers affiliated to Mashhad University of Medical Sciences with a capacity of more than one hundred beds, which included twelve public hospitals and forty-eight sections. To collect information, methods of observing and studying documents, records and statistics of hospital activities have been used. For validation, by calculating Spearman correlation coefficient, it was found that the proposed model has a significant correlation with the Black Box DEA Model and the validity of the model was confirmed. SOLVER DEA and EXCEL software were used to implement the model.

The results show that by considering the internal departments of the organization as well as the relations between the departments, a more accurate analysis of the efficiency of the hospitals would be done and we will have a better separation in the ranking between the organizations. Also, by using the network DEA model, the overall efficiency, the efficiency of each department and the rank of each department in comparison with similar departments in other hospitals are determined.

The framework presented in this study can be an appropriate criterion for measuring the efficiency of hospitals and their internal sections by determining the overall position of each hospital relative to other hospitals and by determining the efficiency of the section. By determining the efficiency of the internal departments of hospitals, a suitable priority is provided for allocating resources and investing in different departments in the direction of organizational improvement.

In this research, a model with three objective functions is presented to solve the problem of time, cost and quality trade-off in project planning. What distinguishes this model is that, in addition to considering different executive methods for each activity, rework activity is defined for some activities in order to prevent a decrease in quality. Other features of this model include covering various costs including incentive cost and tardiness cost. Because of the NP-Hardness of such large-scale problems, genetic algorithm is used to solve the proposed model.The results obtained from solving a real problem in screen filter production indicate that considering different executive methods for activities as well as different costs and defining rework activity can lead to better results towards the final goal by presenting a comprehensive model.If more accurate and detailed information is used for time, cost and quality in the model, it can achieve more rational results, similar to those of the real world more confidently. Under such conditions the least time and cost and most quality are achieved for successful implementation of project.

The structure of the strategy is a hierarchy that links a general strategy to more detailed details. An initial look at these structures reveals similarities and differences. Today's existence of this diversity is the source of new problems for strategic planners and managers.
Diverse experts have explained the organizations’ general strategies and each from his or her viewpoint has explained the structure of these strategies. But the adaptive measures of the diverse strategy structures have not been noted. The present research has been done so as to reduce the ambiguity of the Iranian managers and planners which derive from the different strategy structures.
The strategy concept is a hierarchy that binds a general strategy to more detailed strategies. A preliminary look at these structures reveals their similarities and differences.
In one type of organization, organizational strategies can be identified in two types: general strategies and specialized strategies. Strategic strategies are strategies that are monopolized by an organization, industry or specific geographic range, and can never be a potential option for all organizations. In contrast to the general strategies, there are strategies that can be placed on the management board of all organizations for selection.
A common practice in strategic planning is to measure a valid pattern and structure that has taken its credibility from its own opinion. For this reason, for strategic planners whose practice is to use standardized strategy structures, the complexity of the future structure may lead to strategic pricing for their organization. The seemingly minor but important differences in various strategies of the strategy may indicate the existence of imperfections in these structures and their lack of comprehensiveness.
In this research; the first step was to find out the most frequent general strategy structures that have academic and executive usage in Iran. After that these were compared and contrasted. Comparative comparison was done through two phase. In the first phase, comparison between structures was done pairwise. In the next phase, the results of pair comparison summarized in the term of intersections, differences and circumscriptions. Differences emerged at three subject: in the tilted of strategy, in the concept of strategy and in structural position of strategy. Intersections included strategies that have same title, concept and position in different structures.
In this study, in order to increase the accuracy level, the study was carried out in two stages: in the first stage, the comparison between the structures was made in two ways, and in the next step, the results of paired comparisons were summed up in the form of commons, differences, and monopolies of the structures.
Discussion and The purpose of this study was to provide an answer to the differences in the various strategies of the strategy to make the options on the table more transparent for strategic planners. To this end, valid and widely applicable public sector structures in the developed country were considered comparable. The main results of this comparison were as follows: Integration and diversity strategies were common in all structures. Competitive strategies, market development, product development, partnership, reduction in two or more structures are mentioned. The focus strategy has appeared in different structures with the same name but different meanings. Growth strategies, horizontal diversity, innovation, and stability are proposed only in a structure.
At the end of the comparative survey results, a comprehensive structure of public strategies was inferred, which could serve as a comprehensive reference point for organizational strategies for strategic planners. This structure states that strategies at the business level should include three categories of growth, stability and reduction. The growth strategy will be of two types: competitive and participatory. The stability strategy consists of three types of profit, no change and stop. The strategy of reduction is also based on four types of captivity, change of direction, assignment and dissolution. But the strategy at the organization level should include three types of growth, stability and reduction. Its growth strategy focuses on four types of concentration, diversity, integration and defensiveness. Stability strategies and similar reductions are defined as defined at the business level.
The proposed structures can be a new reference point for choosing a strategy between academics and strategic planners. Because in the design of this structure, on the one hand, the differences in the known strategy structures are reasonably summed up and, on the other hand, all the strategies presented in these structures are in the right place. Structural strategies of the comparative study in this research were limited to five valid and widely used structures in the country. Undoubtedly, the structures provided by leading and, at the same time, world-class experts, are far more likely to be the subject of future research. finally, from the compared and contrasted data a comprehensive structure of general strategies that can be used as a comprehensive reference of general strategies by strategic planners were obtained.

In recent years many methods to generate fuzzy rules based on training samples is proposed. One of the methods that recently suggested is Chen & Tsai’s method that was presented in 2008. This method was based on three indices: Attribute Threshold Value (), Classification Threshold Value () and Level Threshold Value (). This method has a higher average classification accuracy rate than other methods available. In part of generating interim rules, Authors have provided suggestions to improve method and they used modified method in a case study. What in this research has been considered is the examining of CT08 improved method in an applied field on the one hand, and presentation of a classification system for mobile sets on the other hand. Improved method depicted higher accuracy than original method (about 0.2 in mobile set subject).