QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
An Efficient Extension of Network Simplex Algorithm
1
10
EN
Hassan
Rashidi
School of Computer Science and Electronic Systems Engineering, University of Essex, Colchester CO4 3SQ, U.K.
hrashi@essex.ac.uk
Edward P.K
Tsang
School of Computer Science and Electronic Systems Engineering University of Essex, Colchester CO4 3SQ, U.K.
edward_@essex.ac.uk
In this paper, an efficient extension of network simplex algorithm is presented. In static scheduling problem, where there is no change in situation, the challenge is that the large problems can be solved in a short time. In this paper, the Static Scheduling problem of Automated Guided Vehicles in container terminal is solved by Network Simplex Algorithm (NSA) and NSA+, which extended the standard NSA. The algorithms are based on graph model and their performances are at least 100 times faster than traditional simplex algorithm for Linear Programs. Many random data are generated and fed to the model for 50 vehicles. We compared results of NSA and NSA+ for the static automated vehicle scheduling problem. The results show that NSA+ is significantly more efficient than NSA. It is found that, in practice, NSA and NSA+ take polynomial time to solve problems in this application.
Container Terminals,Minimum Cost Flow Problem,Network Simplex Algorithm,Optimization methods,Scheduling
http://www.qjie.ir/article_2.html
http://www.qjie.ir/article_2_c771558e5824200ce81e298f9b1b8be5.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Multiple Batch Sizing through Batch Size Smoothing
11
17
EN
Mir bahadorgholi
Aryanezhad
Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran
Mehdi
Karimi nasab
Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran
mehdikariminasab@yahoo.com
Sudabeh
Bakhshi
Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran
Batch sizing in different planning period is categorized as a classical problem in production planning, that so many exact & heuristic methods have been proposed to solve this problem, each of which considering various aspects of the original problem. The solution obtained from majority â€“ e.g. MRP â€“ is in this format that there may be some periods of idleness or each period should produce as needed in different adjacent periods. If there are more the one final independent product to be produced in a factory, this makes the production planning experience strong variations in batch sizes for different periods, which production managers are opposed to these proposed production plans. In this paper, some of the models are proposed to solve this shortcoming of the production plan to smooth the variation of batch sizes and consequently to meet the managers ideal. Finally all of the proposed models are used in a real case problem and the best model is introduced in that case.
Batch Sizing,Ideal Batch Size,Material Requirement Planning (MRP),Production Smoothing
http://www.qjie.ir/article_3.html
http://www.qjie.ir/article_3_cacd532dc6ced339bea01b7004bbc6bd.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Traffic Flow Analysis Based on Queuing Models
19
23
EN
Mohammad
Modares
Industrial engineering department, Sharif university of technology, Tehran, Azadi ave, IRAN,
m.modares@sharif.edu
Hossein
Beheshti Fakher
Engineering deputy, Iran khodro Co, km 14 karaj special road, Tehran, IRAN,
hoseinbf@yahoo.com
One of the most important issues in the plant layout design especially in mass production organizations with high inter-plant logistics isâ€˜material flow and inter-plant traffic analysis and its effects on the production capabilities or pauses in production lines. In this paper the inter-plant traffic analysis issue on the basis of single channel queue model (M/M/1) is analyzed in a carmaker company (IKCO). Through the analysis, the production stop rate and relevant costs are estimated.
Material flow,Queue,Traffic
http://www.qjie.ir/article_4.html
http://www.qjie.ir/article_4_d195bb1649a86bd0f21e3d80e675b8d2.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Change Point Estimation of a Process Variance with a Linear Trend
Disturbance
25
30
EN
Rassoul
Noorossana
Department of Industrial Engineeing, Iran University of Science and Technology, Narmak, Tehran, 16846-13114, Iran
rassoul@iust.ac.ir
Majeed
Heydari
Department of Industrial Engineeing, Iran University of Science and Technology, Narmak, Tehran, 16846-13114, Iran
When a change occurs in a process, one expects to receive a signal from a control chart as quickly as possible. Upon the receipt of signal from the control chart a search for identifying the source of disturbance begins. However, searching for assignable cause around the signal time, due to the fact that the disturbance may have manifested itself into the rocess sometimes back, may not always lead to successful identification of assignable cause(s). If process engineers could identify the change point, i.e. the time when the disturbance first manifested itself into the process, then corrective actions could be directed towards effective elimination of the source of disturbance. In this paper we develop a maximum likelihood estimator (MLE) for process change point designed to detect changes in process variance of a normal quality characteristic when the change follows a linear trend. We describe how this estimator can be used to identify the change point when a Shewhart S-control chart signals a change in the process variance. Numerical results reveal that the proposed estimator outperforms the MLE designed for step change when a linear trend disturbance is present.
Assignable cause,Change point estimation,Maximum Likelihood Estimator,Newton method,Shewhart S-control chart,Statistical process
control
http://www.qjie.ir/article_5.html
http://www.qjie.ir/article_5_7d03aa64573c6b0c47c39cca35614757.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Vendor Selection:
An Enhanced Hybrid Fuzzy MCDM Model
31
39
EN
Behnam
Vahdani
Department of Industrial and Mechanical Engineering, Qazvin Azad University, Qazvin, Iran
Akbar
Alem-Tabriz
Department of Industrial Management, Management and Accounting Faculty, Shahid Beheshti University, G.C., Tehran, Iran
Mostafa
Zandieh
Department of Industrial Management, Management and Accounting Faculty, Shahid Beheshti University, G.C., Tehran, Iran
m_zandieh@sbu.ac.ir
The objective of this article is to develop an empirically based framework for formulating and selecting a vendor in supply chain. This study applies the fuzzy set theory to evaluate the vendor selection decision. Applying Analytic Hierarchy Process (AHP) in obtaining criteria weights and applied Technique for Order Performance by Similarity to Idea Solution (TOPSIS) for obtaining final ranking of vendors. The usefulness of this model is explained through an empirical study for vendor selection.
Analytic hierarchy process (AHP),Fuzzy multi criteria decision making (FMCDM),Technique for Order Performance by Similarity to Idea Solution (TOPSIS),vendor's selection
http://www.qjie.ir/article_6.html
http://www.qjie.ir/article_6_02bb5efab185f23ae90083a994925a6c.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Designing Solvable Graphs for Multiple Moving Agents
41
54
EN
Ellips
Masehian
Industrial Engineering Dept., Tarbiat Modares University, Tehran, 14115-317, Iran
masehian@modares.ac.ir
Farzaneh
Daneshzand
Industrial Engineering Dept., Tarbiat Modares University, Tehran, 14115-317, Iran
Solvable Graphs (also known as Reachable Graphs) are types of graphs that any arrangement of a specified number of agents located on the graphâ€™s vertices can be reached from any initial arrangement through agentsâ€™ moves along the graphâ€™s edges, while avoiding deadlocks (interceptions). In this paper, the properties of Solvable Graphs are investigated, and a new concept in multi agent motion planning, called Minimal Solvable Graphs is introduced. Minimal Solvable Graphs are the smallest graphs among Solvable Graphs in terms of the number of vertices. Also, for the first time, the problem of deciding whether a graph is Solvable for m agents is answered, and a new algorithm is presented for making an existing graph solvable and lean for a given number of agents. Finally, through an industrial example, it is demonstrated that how the findings of this paper can be used in designing and reshaping transportation networks (e.g. railways, traffic roads, AGV routs, robotic workspaces, etc.) for multiple moving agents such as trains, vehicles, and robots.
Deadlocks,Intelligent Moving Agents,Motion Planning,Solvable Graphs
http://www.qjie.ir/article_7.html
http://www.qjie.ir/article_7_0f536d806b7110e5a38db18daf6a50e9.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
Estimation of Products Final Price Using Bayesian Analysis Generalized
Poisson Model and Artificial Neural Networks
55
60
EN
Marjan
Niyati
Department Of Computer Engineering And Information Technology Qazvin Azad University Of Technology ,IRAN
m.Niyati@irantransfo.com
Amir Masud
Eftekhari Moghadam
Department Of Computer Engineering And Information Technology Qazvin Azad University Of Technology ,IRAN
eftekhari@qiau.ac.ir
Estimating the final price of products is of great importance. For manufacturing companies proposing a final price is only possible after the design process over. These companies propose an approximate initial price of the required products to the customers for which some of time and money is required. Here using the existing data of already designed transformers and utilizing the bayesian analysis of generalize poisson models and artificial neural networks, a shortcut method for estimating the material and final price of transformers is established. The proposed method being quite precise and fast, without any cost.
Artificial neural network,Bayesian analysis
http://www.qjie.ir/article_8.html
http://www.qjie.ir/article_8_e5d62fa4b75632de2ca01e8c2289c0c0.pdf
QIAU
Journal of Optimization in Industrial Engineering
2251-9904
2423-3935
Volume 1
Issue 2
2010
02
07
The Capacitated Location-Allocation Problem with Interval Parameters
61
67
EN
Hassan
Shavandi
Department of Industrial Engineering, Sharif University of Technology, Tehran, Iran,
shavandi@sharif.edu
In this paper, we develop a capacitated location-covering model considering interval values for demand and service parameters. We also consider flexibility on distance standard for covering demand nodes by the servers. We use the satisfaction degree to represent the constraint of service capacity. The proposed model belongs to the class of mixed integer programming models. Our model can be reduced to the p-median problem in polynomial time so it is NP-Hard. A genetic algorithm is proposed to solve the developed model and experimental results of solving the model are presented.
Capacitated,Covering,Genetic Algorithms,Interval Parameters,Location
http://www.qjie.ir/article_9.html
http://www.qjie.ir/article_9_7901f56d65c2969ca60f861bf5d2f282.pdf