• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.365-370
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• 1997

In this paper we suggest a development of surface defect inspection algorithms for cold mill strip using tree structure. The defects which exist in a surface of cold mill strip have a scattering or singular distribution. This paper consists of preprocessing, feature extraction and defect classification. By preprocessing, the binarized defect image is achieved. In this procedure, Top-hit transform, adaptive thresholding, thinning and noise rejection are used. Especially, Top-hit transform using local min/max operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, histogram-ratio features are calculated. The histogram-ratio feature is taken from the gray-level image. For the defect classification, we suggest a tree structure of which nodes are multilayer neural network clasifiers. The proposed algorithm reduced error rate comparing to one stage structure.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.147-149
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• 1987

On the colling mill plant, the qulity of products depends on the ability to follow up the command of roll speed and the magnitude of impact drop. In this paper, the frequency response method is applied to the main motor system of No.1 Plate Mill Plant in POSCO. This paper show the influences when the pseudo random noise as test signal is applied to the system to be measured and presents the proper magnitude of test signal.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.152-157
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• 2001

This paper presents the design method of the new controller for looper system in hot strip finishing mill. Looper response time is related to the performance of the tension control to reduce the delivery width error. The quality of the hot strip product, especially width deviation at the top of the strip, is influenced greatly by the precision of tension control. In this paper, a new fuzzy PID control system is designed to obtain the fast looper angle response and the high control precision. The computer simulation to verify the performance of the new controller is executed. From the results of the simulation, the tension control can obtain better performance than that of the conventional PID case.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.11-17
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• 1998

Reducing the effluent discharge from a paper mill is urgently needed due to tightening environmental regulations and economic reasons. For a paper mill to respond to system closure it is required to adopt the best practical retention system that enables the mill to improve fines retention and drainage. In this study, effects of various retention agents on fines retention, drainage and formation were examined using linerboard stock in the laboratory. Among the retention aids tested, high molecular weight cationic polyacrylamides showed good efficiency both in retention and drainage. On the other hand, high charge density, low molecular weight polymeric retention aids showed little improvement both in retention and drainage. The best retention system selected from the laboratory experiment was applied on a paper machine producing linerboard to evaluate its effect on papermaking system closure.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.494-501
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• 2000

This paper describes a strategy of a daily optimal operational scheduling in cogeneration system for paper mill. The cogeneration system selected to establish the scheduling consists of three units and several auxiliary devices. One unit generates electrical and thermal energy using the back pressure turbine. The rest two units generate the energy using the extraction condensing turbine. Three auxiliary boilers, two waste boilers and three sludge incinerators operate to supply energy to the loads with three units. The cogeneration system is able to supply enough the thermal energy to the thermal load, however it can not sufficiently supply the electrical power to the electrical load. Therefore the insufficient electric energy is compensated by buying electrical energy from utility. When the operational scheduling is performed considering the environmental problem. This paper shows the simulation results for daily operational scheduling obtained using the evolutionary algorithm. This results reveal that the proposed modeling and strategy can be effectively applied to cogeneration system for paper mill.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.392-392
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• 2000

This study performs optimization of paper mill scheduling using MINLP(Mixed-Integer Non-Linear Programming) method and 2-step decomposing strategy. Paper mill process is normally composed of five units: paper machine, coater, rewinder, sheet cutter and roll wrapper/ream wrapper. Various kinds of papers are produced through these units. The bottleneck of this process is how to cut product papers efficiently from raw paper reel and this is called trim loss problem or cutting stock problem. As the trim must be burned or recycled through energy consumption, minimizing quantity of the trim is important. To minimize it, the trim loss problem is mathematically formulated in MINLP form of minimizing cutting patterns and trim as well as satisfying customer's elder. The MINLP form of the problem includes bilinearity causing non-linearity and non-convexity. Bilinearity is eliminated by parameterization of one variable and the MINLP form is decomposed to MILP(Mixed-Integer Linear programming) form. And the MILP problem is optimized by means of the optimization package. Thus trim loss problem is efficiently minimized by this 2-step optimization method.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2002.11a
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• pp.115-117
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• 2002

제지산업은 용수 과소비 산업으로 환경보호의 중요성이 대두됨에 따라 폐수발생량 제한 및 신수사용에 많은 제한이 뒤따르게 된다. 당사(한솔파텍)는 공업단지가 아닌 일반 농경지대에 자리잡고 있기때문에 신수사용 및 폐수배출에 많은 제한을 받고있다. 본 발표문은 당사의 지난 1년동안의 용수절감 Project(In-Mill Closed화) 활동을 통해 용수절감 활동의 한모델을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.175.1-175
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• 2001

This paper handles main automation facilities and important control issues for hot rolling mill processes. Starting from the general procedures of production cycle, detailed tension control applications are handled based on field experiences and published research papers. Nowadays, quality control and delivery time control for products is becoming more and more important as the client demand is tighter than any other period. In this respect, control technology in steel making process takes very important position. Therefore, the objective of this paper is to share control problems with the people in academic field and by doing so, to get new and striking solution for the problems.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.413-415
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• 2006

In this article, we tried to find out the potential of new PVAm (Polyvinylamine) Polymer for optimizing Retention and Drainage system. From the mill experimental in Carton board mill, we could find out PVAm can reduce a significant chemical cost with preserving Drainage. Another case of Newsprint laboratory survey, we could find out the formation benefits from optimizing PAM system to PAM + PVAm dual system.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.925-936
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• 2003

The manipulability analysis of the parallel-type rolling mill proposed in Hong et al. [1] is re-visited. The parallel rolling mill uses two Stewart platforms in opposite direction for the generation of 6 degree-of-freedom motions of each roll. The objective of this new parallel rolling mill is to permit an integrated control of the strip thickness, strip shape, pair crossing angle, uniform wear of rolls, and tension of the strip. New forward/inverse kinematics problems, in contrast with [1], are formulated. The forward kinematics problem is defined as the problem of finding the roll-gap and the pair-crossing angle of two work rolls for given lengths of twelve legs. On the other hand, the inverse kinematics problem is defined as the problem of finding the lengths of twelve legs when the roll-gap, the pair-crossing angle, and the position and orientation of one work roll are given. The method of manipulability analysis used in this paper follows the spirit of [1]. But, because the rolling force and moment exerted from both upper and lower rolls have been included in the manipulability analysis, more accurate results than the use of a single platform can be achieved. Two. kinematic parameters, the radius of the base and the angle between two neighboring joints, are optimally designed by maximizing the global manipulability measure in the entire workspace.