international journal of industrial Engineering & Production Research

Modeling and Monitoring Social Ntwork in term of Longitudinal Data

Reza Baradaran Kazemzade

Studying the social networks plays a significant role in everyone’s life. Recent studies show the importance and increasing interests in the subject by modeling and monitoring the communications between the network members as longitudinal data. Typically, the tendency for modeling the social networks with considering the dependency of an outcome variable on the covariates is growing recently. However, these studies fail in considering the possible correlation between the responses in the modeling of social networks. Our study use generalized linear mixed models (GLMMs) (also referred to as random effects models) to model the social network according to the attributes of nodes in which the nodes take a role of random effect or hidden effect in the modeling. The likelihood ratio test (LRT) statistics is implemented to detect change points in the simulated network streams. Also, in the simulation studies, we applied root mean square Error (RMSE) and standard deviation criteria for choosing an appropriate distribution for simulation data. Also, our simulation studies demonstrates an improvement in the average run length (ARL) index in comparison to the previous studies.

Economic effectiveness of Ergonomics interventions

Hassan Sadeghi Naeini

Introduction: This review article has tried to explore the economic effectiveness of ergonomics.
Methods: In this review, PubMed, EBSCO, and Web of Science were selected to find the related articles based on two keywords of ‘ergonomics’ and ‘economics’. Eleven full-text articles (1 in PubMed, 8 in EBSCO, and 2 in Web.Sci.) were included in the study.
Results: Articles show that ergonomics interventions have an association with economics and productivity; however 3 out of 11 articles didn’t show a clear interconnection between ergonomics and economic benefits. All of the reviewed articles conducted at workplaces and also were related to occupational ergonomics, but in a single case, the ergonomics product design was reflected a cost-benefit approach.
Discussion: The role of a healthy workforce and ergonomics design regard to both employees’ efficiency and business growth, are often neglected. According to reviewed papers, the role of ergonomics in green economics toward sustainability is inevitable. However, there are some challenges to persuade the industrial sectors’ managers about the economics side of ergonomics in which limited documents and the lack of ergonomics-economics models and procedures are critical.
Conclusion: This review emphasized on at least two approaches. One of them is the necessities of publishing papers, including valid economics model about industrial ergonomics, another one is to develop some economics tools to confirm the benefits of ergonomic product design. If some appropriate economic models or techniques merge into ergonomics intervention projects, whether industrial ergonomics or product design, more feasible and better outcomes will gain in which both of the employees and customers are satisfied.

Project scheduling problem with resource constraints and activities interruption using Bees algorithm

Soroush Avakh Darestani

Project scheduling problem with resources constraint is a well-known problem in the field of project management. The applicable nature of this problem has caused the researchers’ tendency to it. In this study, project scheduling with resource constraints and the possibility of interruption of project activities as well as renewable resources constraint has been also applied along with a case study on construction projects. Construction projects involve complex levels of work. Making wrong decisions in selecting methods and how to allocate the necessary resources such as manpower and equipment can lead to the results such as increasing the predetermined cost and time. According to NP-Hard nature of the problem, it is very difficult or even impossible to obtain optimal solution using optimization software and traditional methods. In project scheduling using CPM method, critical path is widely used; however, in this method, the resource constraints is not considered. Project Scheduling seek proper sequence for doing the project activities. This study has been conducted using Bees meta-heuristic algorithm, with the aim of optimizing the project completion time. Finally, the results obtained from three algorithms and GAMS software shows that this algorithm has better performance than and the solution among the other algorithms and has achieved the accurate solutions.

[1] Critical Path Method

Multi-mode resource constrained project scheduling problem: a survey of variants, extensions, and methods

Siamak Noori

The Multi-Mode Resource Constrained Project Scheduling Problem (MMRCPSP) is one of the most important problems in project scheduling context. The MMRCPSP consists of activities to be scheduled subject to precedence and resource constraints. The effort needed in order to accomplish activities in the MMRCPSP is a discrete function of job performing modes. However, MMRCPSP is a basic model with a rather too restrictive assumptions to be applied practically. Therefore, there are many extensions over basic MMRCPSP model in terms of objective functions, resource constraints, and solving procedures. This research is aiming at fulfilling tow ambitions. First, to collect researches related MMRCPSP and to classify them based on a framework consisting of six distinct classes. Second, to indicate current trends and potential areas of future research. In order to fulfill the second goal a new mathematical method is proposed and applied which identify recent trends and gaps in a systematic manner.

Analyzing effective factors in Green information systems (ISs) adoption in health care centers using interpretive structural modeling

Hossein Sayyadi Tooranloo

Health care centers as an important part of health care industry, in addition to following their major mission, that is, providing high quality health service, can gain environmental and even socioeconomic advantages through reducing environmental effects resulted from their activities. With the goal of gaining these advantages, health care centers can increase their environmental performance through adopting a systematic and proper approach in application of information systems (ISs). The Green information systems (ISs) that indicate a novice approach in application of ISs are considered as necessary tools to realize the goals of environmental sustainability. Different factors affect Green ISs adoption by health care centers. In this research, these factors were first identified through library method and review of the literature. Then, the relationships between these factors were analyzed and modeled using interpretive structural approach. According to the results, the volume of social investment, research and development along with the senior management’s insight and commitment are the most important factors affecting Green ISs adoption in the health care centers.

Bi-Criteria Robotic Cell Scheduling and Operation Allocation in the Presence of Break-downs

Hiwa Farughi

This paper focused on scheduling problems arising in a two-machine, identical parts robotic cell configured in a flow shop. Through current research, a mathematical programming model on minimizing cycle time as well operational cost, considering availability of robotic cell as a constraint, is proposed to search for the optimum allocation and schedule of operations to these two machines. Two solution procedures, including weighted sum method and ∊-constraint method are provided. Based on the weighted sum method, like some previous studies, sensitivity analysis on model parameters were done and the optimum solutions were compared with previous results, while the ∊-constraint method can find the Pareto optimal solutions for problems with up to 18 operations in a reasonable time.

Using Fuzzy FMEA approach to improve decision-making process in CNC machine Electrical and control equipment failure prediction

Abbas Rohani

Nowadays, the CNC machining industry uses FMEA approach to improve performance, reduce component failure, and downtime of the machines. FMEA method is one of the most useful approach for the maintenance scheduling and consequently improvement of the reliability. This paper presents an approach to prioritize and assessment the failures of electrical and control components of CNC lathe machine. In this method, the electrical and control components were analyzed independently for every failure mode according to RPN. The results showed that the conventional method by means of a weighted average, generates different RPN values for the subsystems subjected to the study. The best result for Fuzzy FMEA obtained for the 10-scale and centroid defuzzification method. The Fuzzy FMEA sensitivity analysis showed that the subsystem risk level is dependent on O, S, and D indices, respectively. The result of the risk clustering showed that the failure modes can be clustered into three risk groups and a similar maintenance policy can be adopted for all failure modes placed in a cluster. Also, The prioritization of risks could also help the maintenance team to choose corrective actions consciously. In conclusion, the Fuzzy FMEA method was found to be suitably adopted in the CNC machining industry. Finally, this method helped to increase the level of confidence on CNC lathe machine.

A stochastic multi objective mathematical model to optimize a production and distribution system with stochastic demand and stochastic lead time

mohammad Bagher Fakhrzad

Abstract
Production and distribution network (PDN) planning in multi-stage status is commonly complex. These conditions cause significant amount of uncertainty relating to demand and lead time. In this study, we introduce a PDN to deliver the products to customers in the least time and optimize the total cost of the network, simultaneously. The proposed network is four stage PDN including suppliers, producers, potential entrepots, retailers and customers with multi time period horizon with allowable shortage. A mixed integer programming model with minimizing total cost of the system and minimizing total delivery lead time is designed. We present a novel heuristic method called selective firefly algorithm (SFA) in order to solve several sized especially real world instances. In SFA, each firefly recognizes all better fireflies with more brightness and analyses its brightness change before moving, tacitly. Then, the firefly that makes best change is selected and initial firefly moves toward the selected firefly. Finally, the performance of the proposed algorithm is examined with solving several sized instances. The results indicate the adequate performance of the proposed algorithm.