International Journal of Industrial Engineering: Theory, Applications and Practice
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The Comparison of Artificial Intelligence and Traditional Approaches In FCCU Modeling
Get PDFFCCU (Fluid Catalytic Cracking Unit) is a part of oil refinery production process whereby valuable products such as gasoline, LPG (Liquid Petroluem Gas), diesel are manufactured in a short period of time. The objective of this paper is to find the most robust model by comparing the models of FCCU that are developed using different methodologies. The models of FCCU are developed by using Artificial Neural Network (ANN), Fuzzy Logic, Neuro-Fuzzy, and traditional methodology. In this paper, the criteria used for measuring the performance of different models is root mean squared error (RMSE). The models are applied to the real data obtained from TUPRAS (Turkish Petroleum Refineries Corporation)-FCCU. Kurihara (1967) model is used as the traditional model for comparing with intelligence modeling techniques. Finally, the Fuzzy Neural Network (FNN) model was found as the model with the minimum RMSE. Qwicknet 2.23, MATLAB 6.5, and Neuro-solutions 4.1 softwares have been used for the construction of ANN, fuzzy, and neuro-fuzzy models, respectively
Extracting Knowledge of Concrete Shear Strength from Artificial Neural Networks
Get PDFThis article introduces an artificial neural network (ANN) to estimate the shear strength of reinforced concrete beams. Current methods for calculating shear strength use a model that is based on engineering mechanics and empirical values determined though testing of a beam failing due to shear. The current methods are intended to provide a conservative lower bound on the strength needed to prevent a shear failure. A database containing the results of over 1200 laboratory shear strength tests was used to train an ANN. The database contained the geometric and material property data from the test specimens and the recorded failure load. The ANN presented in this paper was able to predict the shear strength of reinforced concrete beams more accurately than the current approach. The ANN provides additional insight on the parameters that are most significant in estimating concrete shear strength, which may lead to a better understanding of the mechanism of shear failure
Modeling of A Pull-Push Assembly Control System To Minimize Inventory and Demand Delay Costs
Get PDFThis study deals with modeling and analysis of an electronic assembly line, which operates according to a pull-push system of production control. Weekly scheduled demands are met from finished products inventory, which in turn trigger production at the first station by signaling with certain number of kanbans, which are equal to the product quantity withdrawn. The successive assembly operations are performed using a push system of production control. The objective of the simulation analysis presented in this paper is to determine the optimum number of kanbans attached to the batches of products in the system to minimize the total system cost, which consists of inventory holding cost, demand delay cost, and transportation costs due to regular and additional shipments of deman
A Multi-Variate/Multi-Attribute Approach for Plant Layout Design
Get PDFThis paper presents an integrated multivariate and multi attribute analysis approach for solving plant layout design problems. The integrated approach discussed in this paper is based Principal Component Analysis (PCA) and Analytic Hierarchy Process (AHP). The validity of the model is verified and validated by Numerical Taxonomy (NT) approach. Furthermore, a non-parametric correlation method, namely, Spearman correlation experiment is used to show the correlation between the findings of PCA and NT. The integrated PCA AHP approach of this study presents exact whereas previous DEA AHP studies presents incomplete and non exact plant layout alternatives. Furthermore, the superiority and effectiveness of PCA AHP approach is compared with previous DEA AHP study through a case study. The integrated PCA AHP would help policy makers and top managers to have precise understanding and improve existing systems with respect to facility layout performance. Furthermore, it provides complete and exact rankings of the plant layout alternatives. Moreover, Numerical Taxonomy is used to verify and validate the findings of PCA whereas previous DEA AHP does not have verification and validation feature
Assessing the Availability and Allocation of Production Capacity in a Fabrication Facility Through Simulation Modeling: A Case Study
Get PDFFor a tier two automobile supplier’s fabrication facility, the manufacturing process required producing two classes of products, those produced on a repetitive and those produced on a periodic basis. Static capacity analysis determined if sufficient gross capacity existed in the production system in order to meet customer demand but was unable to determine if the capacity was available at the desired times to preserve an acceptable service level. A simulation model was developed to confirm the sequencing and scheduling of both classes of products. The model also incorporated the logistical constraints of customer supplied materials used in the production process. The simulation output was able to evaluate the system performance metrics regarding material availability, transportation efficiencies, product backorders, and interruptions to the production process. The model provided a planning tool that assessed the quarterly production plan; identified customer service issues and evaluated the impact of continuous improvement efforts
Electroplating Line Flexible Control using P-Time Petri Nets Modeling and Hoist Waiting Times Calculation
Get PDFIn automated electroplating lines, product quality depends on soak times in chemical tanks while line throughput depends on hoist moves cycle time. These parameters are antagonistic since on-line tuning of cycle time interferes with processing duration and thus quality, and vice versa. Furthermore, on-line tuning actions performed without exploiting process flexibility may affect hoist moves schedule feasibility and call for complex scheduling at the on-line level. In this paper a flexible control for electroplating lines (EPL) is proposed that allows quality and throughput tuning within calculated margins and with no need for hoist moves rescheduling. Firstly a P-time Petri Nets (P-time PNs) tool is used to model hoist move sequence. Afterwards, linear programs (LP) are proposed to determine cycle time and soak times tuning margins without the need to reschedule hoist moves. Flexibility will be achieved using empty-hoist wait times
COMPARISON OF ALTERNATIVE SHIP-TO-YARD VEHICLES WITH THE CONSIDERATION OF THE BATCH PROCESS OF QUAY CRANES
No full textContainer terminals around the world fiercely compete to increase their throughput and to accommodate new mega vessels. In order to increase the port throughput drastically, new quay cranes capable of batch processing are being introduced. The tandem-lift spreader, equipped with a quay crane, which can handle one to four containers simultaneously has recently been developed. Such increase in the handling capacity of quay cranes requires significant increase in the transportation capacity of ship-to-yard vehicles as well. The objective of this study is to compare the performances of three alternative configurations of ship-to-yard vehicles in a conventional container terminal environment. We assume that the yard storage for containers is horizontally configured and the quay cranes equip with tandem-lift spreaders. A discrete event simulation model for a container terminal is developed and validated. We compare the performances of the three alternatives under different cargo workloads and profiles, represented by different annual container handling volumes and different ratios of tandem mode operations, respectively. The results show that the performances of the alternative vehicle types are largely dependent on workload requirement and profile
MODELING AND SIMULATION ANALYSIS OF AIRCRAFT MAINTENANCE OPERATIONS
No full textThis study examines a specific airline’s aircraft maintenance operations and proposes three modeling and analysis methodologies for maintenance-related issues. To determine if standard maintenance times should be multiplied by suppliers and company factors to calculate the permissible times for the technicians, a set of hypotheses is first formulated and tested. Second, four elements that affect aircraft maintenance delays are identified at various levels, and associated data is collected using work measurement techniques. The data is then examined by the Design of Experiments (DOE) to determine the factors that most significantly affect the delays in maintenance operations. Third, a comprehensive and detailed simulation model is developed to evaluate alternative scenarios that could improve maintenance operations and reduce maintenance cycle times. The optimum options are selected, which shorten maintenance cycles and increase resource utilization. For aircraft maintenance engineers and operations managers, the modeling approaches and results presented in this study might be valuable in analyzing and improving their systems
DATA-DRIVEN APPROACH TO EXPLORE EMPLOYEES’ JOB NEEDS: AN EMPIRICAL STUDY OF DEPARTMENT STORE CHAIN IN TAIWAN
No full textFulfilling employee job needs is key for increasing job satisfaction and reducing turnover intention. However, this psychological and behavioral process is complex, and employees with heterogeneous demographics may prioritize different psychological needs. Therefore, planning human resource strategies that can effectively fulfill employee needs which are critical to job satisfaction and turnover intention, is challenging for organizations. Data mining techniques were employed to investigate the complex and interactive effects of employee job needs and demographics on employee outcomes. Data were collected from 1579 employees of a company in Taiwan. The results revealed that data mining techniques can not only effectively identify meaningful relationships without prior hypotheses but can also discover previously unknown, non-general, and case-specific knowledge patterns. The findings can serve as guidelines for service managers attempting to address employee job needs to increase employee satisfaction, reduce turnover intention, and increase organizational competitiveness
MATHEMATICAL MODELING APPROACH FOR EMERGENCY EDUCATION OF REFUGEES IN DEVELOPING COUNTRIES
No full textIt is very important to increase the efficiency of humanitarian logistics (HL) operations during the post-disaster phase in order to avoid human and economic losses. In this paper, two mathematical models have been developed to fulfill the educational needs of refugees in developing countries. Two different policies based on additional placement or planning of a double-shifting system in existing schools and opening new temporary education centers in terms of efficient use of scarce resources (funds) and enrollment of more refugees into the education system have been examined. The proposed models have been shown in a real-life case. In the first model, 1130 children cannot access education because of the capacity constraints and maximum coverage distance, while in the second model, the number of unschooled children is increased by 426. Results show that the main problems are the capacity shortage in existing schools and the insufficient budget for opening new schools