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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Institute of Industrial Engineers
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Journal DOI :
Korean Institute of Industrial Engineers
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Volume & Issues
Volume 21, Issue 4 - Dec 1995
Volume 21, Issue 3 - Sep 1995
Volume 21, Issue 2 - Jun 1995
Volume 21, Issue 1 - Mar 1995
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Application of the Numerical Integration Method in a Repair Facility Using SIMAN and FORTRAN
Jung, Won ; Rhee, Hahn-Kyou ; Park, Min-Yong ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 463~477
This paper presents a decision model that will estimate the expected number of failed units in a repair facility in accordance with the varying demand, and determine the required number of personnel for repairing components. The demand is related to the failure process which follows a reliability growth phenomenon in service. The information in this paper is useful for selecting appropriate scheduling rules and spares stocking policies. SIMAN and FORTRAN were used for computing the time dependent performance measures in the repair facility. The numerical integration method that is presented in this paper will provide accurate performance measures with any dynamic pattern of demand, service rates, and any number of servers.
An Improved Procedure for Component Scheduling in Two Printed Circuit Pack Sequencers
Kim, Hyoun-S. ; Kang, Hyoun-G. ; Lee, Chae-Y. ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 479~491
An improved heuristic procedure is presented which minimizes the changeovers of components in manufacturing printed circuit packs (PCP). The proposed procedure first groups similar components and PCPs together as in an existing method. The procedure then assigns each group to a machine such that the load on two machines is balanced. Considerable improvement is obtained compared to the best procedure available in the literature.
Intersections of a Polyhedral Surface with Parallel Planes
Jeon, Cha-Soo ; Kim, Young-Yil ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 493~506
Presented in this paper is an algorithm to obtain the intersections of a polyhedral surface composed of triangle facets with a series of parallel planes for extracting machining information from the surface. The change of the topology of the intersection curves is caused by characteristic points of the surface when sectioning the surface with parallel planes. The characteristic points are internal maximum, internal minimum, internal saddle, boundary maximum, boundary minimum, boundary max-saddle, and boundary min-saddle points. The starting points of the intersects are found efficiently and robustly using the characteristic points. The characteristic points as well as the intersection contours can be used to evaluate the machining information for process planning, and to generate NC tool path in CAD/CAM system.
Optimal Preventive Replacement Policies for a Change of Operational Environment
Kong, M.B. ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 507~517
The failure rate of an item depends on operational environment. When an item has a chance failure period and a wearout failure period in sequel, the severity of operational environment causes the increase in the slop of wearout failure rate or the increase in the magnitude of chance failure rate. For such a change of operational environment, this paper concerns the change of optimal preventive replacement time. Two preventive replacement policies, age replacement policy and periodic replacement policy with minimal repair, are considered. Investigated properties are: (a) in age replacement policy, optimal preventive replacement time increases as the chance failure rate increases and optimal preventive replacement time decreases as the slope of wearout failure rate increases, and (b) in periodic replacement policy with minimal repair, optimal preventive replacement time increases as the slope of wearout failure rate increases; however, the change of chance failure rate does not alter the optimal preventive replacement time.
A Fast Algorithm for the Generalized Multiple Choice Linear Knapsack Problem
Won, Joong-Yeon ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 519~527
By finding some new properties, we develop an O(
) algorithm for the generalized multiple choice linear knapsack problem where
is the largest multiple choice number and n is the total number of variables. The proposed algorithm can easily be embedded in a branch-and-bound procedure due to its convenient structure for the post-optimization in changes of the right-hand-side and multiple choice numbers. A numerical example is presented.
A Study of a Surface Modeling Interpolating a Polygonal Curve Net Constructed from Scattered Points
Ju, Sang-Yoon ; Jun, Cha-Soo ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 529~540
The paper deals with a procedure for constructing a composite surface interpolating a polygonal curve mesh defined from 3D scattered points. The procedure consists of a poly-angulation, construction of a curve net, and interpolation of the curve net. The poly-angulation contains a stage that changes a triangular edge net obtained from a triangulation into a poly-angular edge net. A curve net is constructed by replacing edges on the edge net with cubic Bezier curves. Finally, inside of an n-sided polygon is interpolated by n subdivided triangular subpatches. The method interpolates given point data with relatively few triangular subpatches. For an n-sided polygon, our method constructs an interpolant with n subdivided triangular subpatches while the existing triangular surface modeling needs 3(n-2) subpatches. The obtained surface is composed of quartic triangular patches which are
-continuous to adjacent patches.
The Buffer Allocation with Linear Resource Constraints in a Continuous Flow Line
Seong, Deok-Hyun ; Chang, Soo-Young ; Hong, Yu-Shin ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 541~553
An efficient algorithm is proposed for a buffer allocation in a continuous flow line. The problem is formulated as a non-linear programming with linear constraints. The concept of pseudo gradient and gradient projection is employed in developing the algorithm. Numerical experiments show that the algorithm gives the actual optimal solutions to the problems with single linear constraint limiting the total buffer capacity. Also, even in longer production lines, it gives quite good solutions to the problems with the general linear resource constraints within a few seconds.
A Preventive Replacement Model for Standby Systems
Lee, Hyo-Seong ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 555~570
We consider a preventive replacement policy for a cold-standby system with N components, in which only one component is in operation at a time. If the component in operation fails, a standby component is immediately switched into operation. If all components fail, the system fails. The system is inspected at random poins in time to determine whether it is to be replaced or not. If the number of failed components at the time of inspection exceeds a threshold value r, the system is replaced. Otherwise the decision is put off until the next inspection point arrives. Under the cost structure which includes a replacement cost, a system down-time cost and a holding cost of the components, we develop an efficient procedure to find the optimal control values N and r, which minimize the expected cost per unit time.
A New Approach to Medial Axis Transformation of Objects with Smooth Boundary
Wee, Nam-Sook ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 571~580
Medial axis transformation is an important concept used in many engineering applications. We propose a new approach to medial axis transformation of 2D objects with smooth boundary. Our approach differs from the traditional ones: we construct the medial axis starting from the inside points, while the previous algorithms started from the boundary points. As a result, previous algorithms are highly sensitive to the small irregularities of the object's boundary curve, while our approach is robust.
Comparison of Three Existing Methods for Predicting Compressive Force on the Lumbosacral Disc
Kee, Do-Hyung ; Chung, Min-K. ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 581~591
The main objective of this study is to compare three representative methods predicting compressive forces on lumbosacral disc : LP-based method, double LP-based method and EMG-assisted method. Two subjects simulated lifting tasks performed in the refractories industry, in which vertical and horizontal distance, and weight of load were varied. To calculate the L5/S1 compressive forces, EMG signals from six trunk muscles were measured and postural data and locations of load were recorded using the Motion Analysis System. The EMG-assisted model was shown to reflect well all three factors considered here. On the other hand, the compressive forces of the LP-based model and the double LP-based model were only significantly affected by weight of load. In addition, lowly positive correlation was observed between compressive forces of the EMG-assisted model and lifting index(LI) of 1991 NIOSH lifting equation. From this results, it can be concluded that compressive forces on L5/S1 by the EMG-assisted method should be used as biomechanical criterion in order to evaluate risk of jobs precisely, and LI can not evaluate risk of lifting tasks fully.
Development of a Pneumatic Servomechanism Using a Direct-connected Circuit between Inlet and Outlet and Its Application to the Design of a Fuzzy Position Controller for a Fingering System
Choi, Kap-Yong ; Choi, In-Soo ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 593~608
In this study two issues are considered, one is to develop a pneumatic servomechanism using a direct-connected circuit between inlet and outlet, the other is to design two kinds of advanced controllers such as fuzzy and PID controllers for a fingering system. Besides, the application of the advanced controllers to the newly proposed servomechanism is presented. The procedure of this study is composed of following 6 steps : [Step 1] Structuring of a control system; [Step 2] Development of a pneumatic circuit for the servomechanism ; [Step 3] Characteristic analysis of the valve and cylinder systems ; [Step 4] Determination of optimal parameters of the PID controller ; [Step 5] Design of a fuzzy controller and parameter tuning; and, [Step 6] Experimental analysis of fuzzy and PID controllers. Experimental results show that the newly proposed pneumatic servomechanism has good performance and, not only the performance of the fuzzy controller is better than that of the PID controller but also the fuzzy controller fits well to the control of the pneumatic servomechanism.
Reliability Modeling and Analysis for a Unit with Multiple Causes of Failure
Baek, Sang-Yeop ; Lim, Tae-Jin ; Lie, Chang-Hoon ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 609~628
This paper presents a reliability model and a data-analytic procedure for a repairable unit subject to failures due to multiple non-identifiable causes. We regard a failure cause as a state and assume the life distribution for each cause to be exponential. Then we represent the dependency among the causes by a Markov switching model(MSM) and estimate the transition probabilities and failure rates by maximum likelihood(ML) method. The failure data are incomplete due to masked causes of failures. We propose a specific version of EM(expectation and maximization) algorithm for finding maximum likelihood estimator(MLE) under this situation. We also develop statistical procedures for determining the number of significant states and for testing independency between state transitions. Our model requires only the successive failure times of a unit to perform the statistical analysis. It works well even when the causes of failures are fully masked, which overcomes the major deficiency of competing risk models. It does not require the assumption of stationarity or independency which is essential in mixture models. The stationary probabilities of states can be easily calculated from the transition probabilities estimated in our model, so it covers mixture models in general. The results of simulations show the consistency of estimation and accuracy gradually increasing according to the difference of failure rates and the frequency of transitions among the states.
On the Reliability Equivalence
Ahn, C.W. ; Chae, K.C. ;
Journal of Korean Institute of Industrial Engineers, volume 21, issue 4, 1995, Pages 629~638
It is shown that the reliability function of an n-component parallel system is equivalent to that of n-component stand-by system if we increase the exponential failure rates of the parallel system's components in proportion to the increasing load per surviving component.