• Management Science and Financial Engineering
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• v.17 no.2
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• pp.63-84
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• 2011

The ordinary multiple criteria decision making (MCDM) approach requires two types of input, alternative values and criterion weights, and employs two schemes of alternative prioritization, dominance and potential optimality. This paper allows for incomplete information on both types of input and gives rise to the dominance relationships and potential optimality of alternatives. Unlike the earlier studies, we emphasize that incomplete information frequently takes the form of strict inequalities, such as strict orders and strict bounds, rather than weak inequalities. Then the issues of rising importance include: (1) The standard mathematical programming approach to prioritize alternatives cannot be used directly, because the feasible region for the permissible decision parameters becomes an open set. (2) We show that the earlier methods replacing the strict inequalities with weak ones, by employing a small positive number or zeroes, which closes the feasible set, may cause a serious problem and yield unacceptable prioritization results. Therefore, we address these important issues and develop a useful and simple method, without selecting any small value for the strict preference information. Given strict information on both types of decision parameters, we first construct a nonlinear program, transform it into a linear programming equivalent, and finally solve it via a two-stage method. An application is also demonstrated herein.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1-4
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• 2004

The dual-mode strategy has been adopted in many constrained MPC methods. The size of stabilizable regions of states of MPC methods depends on the size of underlying feasible and positively invariant set and number of control moves. These results, however, could be conservative because the definition of positive invariance does not allow temporal leave of states from the set, In this paper, a concept of periodic invariance is introduced in which states are allowed to leave a set temporarily but return into the set in finite steps. The periodic invariance can defined with respect to sets of different state feedback gains. These facts make it possible for the periodically invariant sets to considerably larger than ordinary invariant sets. The periodic invariance can be defined for systems with polyhedral model uncertainties. We derive a MPC method based on these periodically invariant sets. Some numerical examples are given to show that the use of periodic invariance yields considerably larger stabilizable sets than the case of using ordinary invariance.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.530-535
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• 2004

This paper considers a state set estimation (SSE) based model predictive control (MPC) for linear parameter- varying (LPV) systems with input constraint. We estimate, at each time instant, a feasible set of all states which are consistent with system model, measurements and a priori information, rather than the state itself. By combining a state-feedback MPC and an SSE, we design an SSE-based MPC algorithm that stabilizes the closed-loop system. The proposed algorithm is solved by semi-de�nite program involving linear matrix inequalities. A numerical example is included to illustrate the performance of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.871-874
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• 1996

It is practically very important in multi-criteria long-tenn IRP process to develop the set of candidate resource plans that meet following two conditions. First, the number of resource plans should not be too large for computer job. Second, the unknown best plan should exist among the set of candidate plans. In this paper, several novel procedures are developed. The main idea of the procedures is the two-stage approach. The first stage is to find the set of feasible resource capacity mixes in given target year(s). And, the second stage is to find the set of alternative paths of resource options for each resource mix determined in the first stage.

• Management Science and Financial Engineering
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• v.11 no.2
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• pp.45-60
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• 2005

This paper investigates the application of the computer method COMSOAL (Computer Method of Sequencing Operations for Assembly Lines) to the process routing (PR) problem with multiple objectives. In any computer aided process planning (CAPP) system, one of the most critical activities for manufacturing a part could be to generate the sequence that optimizes production time, production cost, machine utilization or with multiple these criteria. The COMSOAL has been adopted to find the optimum sequence of operations that optimizes two major conflicting criteria : production cost and production quality. The COMSOAL is here slightly modified to simultaneously generate and evaluate a set of possible solutions (called as population) instead of processing a solution stepwise in each iteration. The significant features of the COMSOAL include : no parameters settings needed, and a guarantee of feasible solutions. Experimental results show that COMSOAL is a simple but powerful method to quickly generate multiple feasible solutions which are as good as the ones obtained from several other well-known process routing algorithms.

• Journal of the military operations research society of Korea
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• v.13 no.1
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• pp.101-115
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• 1987

This paper presents an optimization based heuristic algorithm for a tour bus scheduling problem where buses consist of various kinds of sightseeing and commutation services. First, this algorithm transforms the prolem into a vehicle routing problem on whose nodes denote trips and arcs denote connections between trips. Second, a greedy heuritic routing technique is applied to find a good feasible bus-route set. Then the greedy feasible solution is improved by the simplex method using column generation technique. The algorithm provides a better near-optimal solution which gives much reductions in the total tour distance and the number of tour buses.

• Journal of Korean Society of Transportation
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• v.12 no.3
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• pp.29-47
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• 1994

Although subway system continues to be the backbone of transportation systems in a city like Seoul, there will still be areas across the city where subway services are not avaliable. Interest has steadily grown to fill this missing routes in overall urban transportation system. Light Rail Transit (L.R.T) system has been recently thought to be an appropriate mode of transportation by businessmen, professionals and transportation industry. In this regards, the purpose of this study is to explore whether L.R.T can be a feasible form of urban rail mode in the context of Seoul. First, the study develops the mathematical models to derive optimum route networks and stations. Integer Programming is employed to determine whether alternative routes are financially viable from the viewpoint of revenue maximization principles. Second, mathematical models developed are applied to Yoido area in order to examine the validity of model structures. The models constructed turns out be capable of handling alternative routes and stations. Application of models are successfully carried out to derive financially feasible set of routes and stations.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.382-386
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• 2009

This paper describes design and analysis techniques of cold forging process for precise producing of T-200 type spider made of SCr420H by utilizing pneumatically operated enclosed die set. Since deducing feasible closing force is an important factor to optimize entire pneumatically operated cold forging system, a series of FE analyses with varying the number of gas cylinders has been carried out to investigate the influence of closing force upon the direction of applied load at die surfaces. It also reveals the optimum distribution of the gas cylinders in terms of the flatness of upper/lower plates.

• Korean Journal of Childcare and Education
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• v.13 no.6
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• pp.43-67
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• 2017

Objective: The purpose of this study was to explore the feasibility to utilize image data recorded and accumulated from CCTV at child care centers. Methods: Literature reviews, consultations and workshops with scholars studying child development, legal professionals, and engineers, focus group interviews with professionals working with young children, and surveys targeting parents, directors and teachers were implemented. Results: It was found the big data from CCTV at child care centers can be used to make policies and implement research as a secondary data set after anonymization. Extracting implicit and useful data from images stored on CCTV is technically feasible. Also, it can be legally guaranteed to analyze the data under the condition of acquiring informed consents. Conclusion/Implications: It was likely to utilize image data from CCTV at child care centers as a secondary data set in order for policy development and scholarly purposes, after overcoming obstacles of the budget for additional infrastructures and consents of information holders.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.502-507
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• 2005

The dual-mode strategy has been adopted in many constrained MPC (Model Predictive Control) methods. The size of stabilizable regions of states of MPC methods depends on the size of underlying feasible and positively invariant sets and the number of control moves. The results, however, may perhaps be conservative because the definition of positive invariance does not allow temporal departure of states from the set. In this paper, a concept of periodic invariance is introduced in which states are allowed to leave a set temporarily but return into the set in finite time steps. The periodic invariance can be defined with respect to sets of different state feedback gains. These facts make it possible for the periodically invariant sets to be considerably larger than ordinary invariant sets. The periodic invariance can be defined for systems with polyhedral model uncertainties. We derive a MPC method based on these periodically invariant sets. Some numerical examples are given to show that the use of periodic invariance yields considerably larger stabilizable sets than the case of using ordinary invariance.