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1. |
A simheuristic for bi-objective stochastic permutation flow shop scheduling problem
, Pages: 57-80 Eliana María González-Neira and Jairo Rafael Montoya-Torres PDF (650K) |
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Abstract: This paper addresses the stochastic permutation flow shop problem (SPFSP) in which the stochastic parameters are the processing times. This allows the modeling of setups and machine breakdowns. Likewise, it is proposed a multi-objective greedy randomized adaptive search procedure (GRASP) coupled with Monte-Carlo Simulation to obtain expected makespan and expected tardiness. To manage the bi-objective function, a sequential combined method is considered in the construction phase of the meta-heuristic. Moreover, the local Search combines 2-optimal interchanges with a Pareto Archived Evolution Strategy (PAES) to obtain the Pareto front. Also, some Taillard benchmark instances of deterministic permutation flow shop problem were adapted in order to include the variation in processing times. Accordingly, two coefficients of variation (CVs) were tested: one depending on expected processing times values defined as twice the expected processing time of a job, and a fixed value of 0.25. Thus, the computational results on benchmark instances show that the variable CV provided lower values of the expected makespan and tardiness, while the con-stant CV presented higher expected measures. The computational results present insights for further analysis on the behavior of stochastic scheduling problems for a better approach in real-life scenarios at industrial and service systems. DOI: 10.5267/j.jpm.2019.1.003 Keywords: Stochastic permutation flow shop, Bi-objective, GRASP, Tardiness, Makespan
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2. |
Reduction of rejection of cylinder blocks in a casting unit: A six sigma DMAIC perspective
, Pages: 81-96 Surjit Kumar Gandhi, Anish Sachdeva and Ajay Gupta PDF (650K) |
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Abstract: Six-Sigma approach is a systematic and scientific operations management methodology aimed at achieving major enhancements in production process through the elimination of waste. In this case, a casting unit manufacturing cylinder blocks has been selected which was experiencing a rejection rate as high as 30% due to formation of blowholes, other than the surface. The main objective of this paper is to identify various causes of occurrence of blow-holes and recommend corresponding remedies to counter these defects by systematic imple-mentation of DMAIC cycle. Both preventive and corrective actions have been recommended to reduce the blowholes and overall improvement is validated through two-proportion test. Results of investigation demonstrated the net significant reduction of blowholes defect from 28,111 to 9,708 parts per million, which results in the net annual savings of INR 12,56,640. DOI: 10.5267/j.jpm.2019.1.002 Keywords: Six sigma, DMAIC, Preventive and corrective actions, Rejection rate
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3. |
Project scheduling and forecasting by laws of physical movement
, Pages: 97-108 Morteza Bagherpour, Hamidreza Mardimamaqani, Amirhossein Fallahdizcheh and Herman Steyn PDF (650K) |
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Abstract: Measuring actual project progress and comparing it with the planned time schedule is essential in controlling of a project. The outcome of the latter follows the s-curve diagram, which compares actual progress with the planned amount and finally analyzing any gap between them to draw directions for project scheduling. However, final duration of the project cannot be either estimated or predicted through conventional methods. The new method, using Rules of kinematics, can calculate the final duration of the project. This novel approach is successfully implemented on a construction project. The first objective in new method is forecasting final duration of the project, finding equation path and draw a new s-curve diagram for actual status during the execution process. The second objective is to evaluate schedule performance of the project and report the status of the project at each period which is a useful tool for managers. DOI: 10.5267/j.jpm.2019.1.001 Keywords: Project progress, Physics rules, Equation path, Final duration, Schedule performance, Cost performance
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4. |
A CRITIC-TOPSIS framework for hybrid renewable energy systems evaluation under techno-economic requirements
, Pages: 109-126 M.O. Babatunde and D. E. Ighravwe PDF (650K) |
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Abstract: The electricity generation policy is a strategic policy that drives development in a community. Energy policies are often analyzed with the aim of generating a reliable and affordable electricity for a community. There is a high probability of achieving this aim when energy policy is combined with a community social, technical, economic and environmental needs. This paper determines a hybrid renewable energy source (HRESs) for a rural community using technical, economic, and techno-economic criteria. The selection process combines Criteria Importance Through Inter-criteria Correlation (CRITIC) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) as a solution method. This approach applicability was tested using six HRESs under economic and technical criteria. Ten technical and nine economic criteria were simulated for the HRESs using HOMER. The results from the HOMER software show that A5(PV/wind/battery) and A6 (PV/battery) had a renewable fraction of 1. The results obtained from the CRITIC method showed that the most important technical and economic criteria were diesel generator and total fuel cost, respectively. From an economic perspective, the best HRES for the case study was A4 (diesel/batteries), while A3 (wind/diesel generator/batteries) was the best HRES from a technical and techno-economic perspectives. DOI: 10.5267/j.jpm.2018.12.001 Keywords: Techno-economic criteria, Hybrid renewable energy system, CRITIC-TOPSIS, WASPAS, Simulation
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5. |
Fuzzy inference system-Latin hypercube simulation: An integrated hybrid model for OHS risks management
, Pages: 127-140 Ehsan Haqiqat, Yahia Zare Mehrjerdi and Ali Zare Bidaki PDF (650K) |
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Abstract: Risk management in construction industry in several cases is not only incomplete regarding the unification of Occupational Health and Safety (OHS) hazards, but it is also incomplete in not having a systematic and innovative method to assess the impacts of these risks on the objectives of a project. An integrated hybrid Fuzzy Inference System-Latin Hypercube Simulation for the evaluation of OHS risks in construction projects is presented in this paper. Prioritization of safety risks systematically without human interference with fuzzy inference system gives the appropriate response to the identified risks. An advanced Monte Carlo simulation is also used for the evaluation of quantitative objectives of a project. This approach allows us to get away from discrimination and simulate the risks with high impacts but with low probabilities. In order to measure the relationship between the occurrences of each of the risks impacts on project objectives, the sensitivity analysis based on Pearson correlation coefficient is used to determine the usefulness of the proposed integrated hybrid method. DOI: 10.5267/j.jpm.2018.11.001 Keywords: Occupational Health and Safety, Healthcare System, Construction Projects, Risk Evaluation, Risk management, sensitivity analysis, Integrated hybrid model
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6. |
A hybrid of Delphi, AHP and TOPSIS Methods for project portfolio management
, Pages: 141-156 Ahmad Borjy, Vahid Baradaran Peyman Zandi and Milad Taheri PDF (650K) |
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Abstract: Due to the importance and complexity of the portfolio management issue, over 100 different techniques have already been presented. In general, the final result of these tools is to create a prioritized list of the projects that must be selected for allocating resources. The use of financial strategies may be misleading in some cases, and it is necessary to combine these methods with other methods such as strategic approaches in order to guarantee a balanced portfolio toward the organizational strategies. On the other, categorizing projects into different baskets allows the organizations to select, evaluate and prioritize the projects in a subset using a set of similar criteria and techniques. In this article, by choosing agriculture sector as a case study, an attempt has been made to study the evaluation, ranking and management of projects with investment classifying strategy of the projects using Delphi, TOPSIS and AHP methods. The results reveal that in similar cases we can use the presented model by determining the type of activity and investment and localization of the indexes. DOI: 10.5267/j.jpm.2019.1.004 Keywords: Ranking investment projects, Portfolio of projects, AHP, TOPSIS and Delphi
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7. |
Impacts of change management on risk and cost management of a construction projects
, Pages: 157-164 Mohamed Ibrahim Khalifa Halou, Razali Samin and Mushtaq Ahmad PDF (650K) |
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Abstract: Construction projects are always problematic and difficult to manage in certain stages. Management in construction industry has been characterized as being weak, insufficient, nebulous, backward and slow to react against changing conditions. This study aims to identify risk and cost managed in the change management of the construction projects. Quantitative study is organized and questionnaire as an instrument is used to collect the information from the construction experts in Klang Valley, Malaysia. Random sampling techniques is used to collect the data, 105 questionnaires are distributed and 90 ones are returned. The correlation analysis shows significant relationship between cost, risk and change management. The reliability test indicates satisfactory result to continue the questionnaire where Cronbach coefficient alpha value exceeds the level of 0.70. The study finds that design changes, client and contractor related changes are mostly occurred in change management of construction projects. Tendering on the basis of an incomplete design, which then changes during the course of the construction has been found as the key reason of the changes. Through a paper based exercise, site memorandums (SM), quoted rates (QR), variation orders (VO) and monthly payment certificates (MPC) are the activities managed by the engineers. Proper planning is the most leading change management in the risk management. Implementation of risk man-agement was found the applied risk management in practice to hindrances. Since this is very vast debated subject, the study has recommended further investigation to include consultant firms for better understanding of the design changes leading to the cost and risk associated. DOI: 10.5267/j.jpm.2019.1.005 Keywords: Construction Projects, Change Management, Cost Management, Risk Management
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8. |
A scientometrics survey on project scheduling
, Pages: 165-176 M. R. Ghaeli and Soheil Sadi-Nezhad PDF (650K) |
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Abstract: In project management, a schedule is considered as a list a project's milestones, activities, and deliverables, normally with some start and finish time schedule, which are estimated by some information incorporated in the project schedule including resource allocation, budget, task duration, and linkages of dependencies and scheduled events. This paper presents a comprehensive review of the studies associated with project scheduling. The study uses Scopus database as a primary search engine and covers 3370 records over the period 1963-2019. The records are statistically analyzed and categorized in terms of different criteria. Based on the survey, "decision support systems" is the keyword which has carried the highest densities followed by heuristics methods. Among the most cited articles, papers published by researchers in Germany have received the highest citations (9084), followed by United States (7058) and Belgium with 4853 citations. DOI: 10.5267/j.jpm.2019.1.006 Keywords: Project scheduling, Highly cited, Country, Scientometrics
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