• Earthquakes and Structures
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• v.11 no.1
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• pp.25-43
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• 2016

The uneven distribution of rolling friction coefficient may lead to great uncertainty in the structural seismic isolation performance. This paper attempts to improve the isolation performance of a spring-damper-rolling isolation system by artificially making the uneven friction distribution to be concave. The rolling friction coefficient gradually increases when the isolator rolls away from the original position during an earthquake. After the spring-damper-rolling isolation system under different ground motions was calculated by a numerical analysis method, the system obtained more regular results than that of random uneven friction distributions. Results shows that the concave friction distribution can not only dissipate the earthquake energy, but also change the structural natural period. These functions improve the seismic isolation efficiency of the spring-damper-rolling isolation system in comparison with the random uneven distribution of rolling friction coefficient, and always lead to a relatively acceptable isolation state even if the actual earthquake significantly differs from the design earthquake.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.150-157
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• 1999

As the customer demands thickness quality stricter, new techniques of automatic thickness control(AGC), is adopted to continuous cold rolling mills. The cold rolling mills of Pohang Works have revamped the existing conventional AGC system that control the thickness at all-stands automatically by the mass flow AGC based on the measurement of strip-speed and thickness between mill stands. The No. 2 Cold Rolling Mill be has adopted the New AGC system since Oct. 1995, and The No.1 Cold Rolling Mill since June. 1999. Thanks to the New AGC system, precise control of thickness is possible not only at constant rolling speed region, but also during line speed up and down. This report describes application techniques of the New AGC system and performance of the system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.429-437
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• 1999

Width variation of the top and bottom ends of steel at finishing rolling in a plate, has been investigated. It was found that width variation after finishing rolling is affected by edging, broadside rolling ratio, longitudinal rolling ratio, width shape after broadside rolling, temperature, width-to-thickness ratio, and so on. A neural network modelling of back propagation has been conducted on the width variation during rolling. Based on these prediction models, a width control system, by which the roll opening and closing of the hydraulic AWC edger can be adjusted during edge rolling in finishing rolling passes, has been developed. Compared to conventional width model, the neural network model is much accurate in a model. The width control system is applied to a newly built production mill.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.112-119
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• 2000

The roll Pass design is one of the most important processes to design the whole equipment of the rods and bars rolling system. In this study, the roll pass design program named TollRo(Rolling Factory Organizer) was developed. conventional methods to design roll pass were analyzed and a new algorithm to design the dimension of the intermediate groove was introduced. Object oriented programming technology was implemented in this design program. It comprises GUI(Graphic User Interface), function of automatic pass design, function of modifying pass schedule and database of material properties. The developed program can be used to design roll pass with consistency for the rods and bars rolling system. The man-hours for the whole design can be drastically reduced. The design parameters of rolling system can be extracted quickly by this program.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.38-38
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• 2000

To fulfill recent requirements for high quality products in steel rolling process, fast responding and easily tunab control system is required and ILQ(Inverse Linear Quadratic) control system may be one of such alternatives. In this paper characteristics of ILQ control and its application to BUR(Back-Up-Roll) eccentricity in strip rolling mill is discussed and compared to polynomial control approaches. Also the rolling mill model and basic principle to control thickness of srip are introduced with control effect by polynomial methods.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.163-168
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• 2005

In case of rolling stock, SEMS is generally applied in the advanced countries, but is start stage in our country. SEMS is defined the system engineering management system in order to achieve the optimized train performance among the several client requirements aspect of technical engineering management during the design life cycle. And the fire engineering activities in hong kong EMU project are introduced aspect of SEMS in this paper. The fire engineering at rolling stock in view of SEMS controls to apply the satisfied interior material by the fire safety standards (regulation of the commute urban subway safety guideline by the MOCT, BS 6853, NFPA 130, NF F 16-101) and to minimize the fire load in order that passengers egress safe from the fired rolling stock. The rolling stock in the advanced countries is designed to stand for 15-20 minutes in considering the rolling stock to be fired in tunnel. For passenger fire safety, the passenger evacuation provision and progress is set up.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.393-397
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• 2005

Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result. This study is designed to analyze the air pressure control about braking force in rolling stock, also, by comparing braking force of high speed railway with that of high speed train. This paper suggests to establish a method of computation of braking force form the air pressure control. And The high speed train researches into patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.438-441
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• 2004

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, a sea-trial test on a pendulum-type MD-ARS passively operated is carried out in Suyoung, Busan. After the system is installed on the cabin of the small leisure boat, a series of test is conducted before and after operating the system. Through the test, it is confirmed that the roll rate of the ship is pretty well reduced by the system.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.648-658
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• 2018

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher's rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.109-118
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• 2004

No.2 PCM (Pickling and tandem cold rolling mill) at Pohang works was revamped in 2003. The purpose of this project is to produce carbon and stainless steel using conventional carbon production process, rolling and annealing. This paper introduces the applied facilities and technologies of PCM which are used in production of carbon and stainless steel. To realize the main purpose of this project, POSCO have developed laser weld technology in normal carbon and special steel (stainless, high carbon and high silicon). And this report describes the method which is developed to get down the surface defect of stainless 400 series. After revamping, No.2 PCM can have competitive power in this field and can supply the special steel using carbon rolling process.