• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.147-151
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• 1997

The dynamic characteristics of Control Element Drive Mechanism (CEDM) in Korea standard Nuclear Power Plant was reviewed as a secondary mass in a simplified two degree of freedom system, while the reactor vessel as a primary mass. The design improvement stratege to minimize each displacement amplitude of these primary and secondary masses was proposed. According to this stratege the designs of CEDM components, the shroud and the pressure housing, respectively, were changed using optimization technique.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.990-996
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• 2005

This paper is countermeasure against the problem point it will be able to occur with infiltration of the hardware and software. And, we proposed the optimum integrated of system construction plan for the SCADA system function set and a system design.

• Proceedings of the Korea Port Economic Association Conference
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• 2003.07a
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• pp.69-88
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• 2003

The purpose of this study is to purpose the need of Masan free Trade Zone and the stratege successful implementation. Masan FTZ was established as a center of general free trade and global distribution by means the promotion of foreign investment in 1970s. To promote the development of MFTZ, in can be proposed a) successful technology innovation, b) reforming of related laws and regulations, c) the care of local government, 4) strengthening of marketing activities, e) deeping of comparative advantage of investment, f) encouraging of strategic industries.

• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.667-680
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• 2014

The purpose of this study was to develop teaching stratege focused on Conservational reasoning, Proportional reasoning, Variable-controlling reasoning, Probabilitic reasoning, Correlational reasoning, Combinational reasoning and investigate its effects on enhancing students' logical thinking skills through the science teaching on common education. And the teaching materials was implemented to 110 students in middle school over about six months. The results indicated that the experimental group presented statistically meaningful improvement in logical thinking skills (p<05). Especially, this teaching stratege was effective on Conservational reasoning, Variable-controlling reasoning, Combinational reasoning but was not effective on Proportional reasoning, Probabilitic reasoning, Correlational reasoning (p<.05). Logical thinking according to the teaching strategy skill was not affected by gender, cognitive level, academic achievement (p<.05).

• Journal of Korea Port Economic Association
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• v.20 no.1
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• pp.79-93
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• 2004

Recently, the change of shipping and port environment has required the new strategy from the liners, terminal operators, ports. The ports of call in the North American and European line also has changed as the Chinese ports made rapid advance. This seems to result from the fact that the trend of the container transportation by sea has developed the traditional concept, called port-to-port system that directly links between a port and another port into the network with complicated hierarchical structure reflecting costs, efficiency, and strategy of the Mega Carrier. This paper suggests the factors for Busan port to become the hub port of northeast Asia by analyzing the change of the liners' strategy along the change of the shipping and port environment, the global management of the operator of container port, and the amount of containers flowing in the northeast Asia.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.521-527
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• 2003

Modern automatic transmissions equip torque converters with lock-up clutches to reduce the energy loss of hydraulic systems. Instead of simply engaging the clutch disks, the new technology of clutch slip has been developed to improve the overall efficiency of power transmission. There are two major problems with the clutch slip system. The first is how to keep the slip between the two disks within a small range and the second is when to start or stop the slip. In this paper, the second problem is discussed in view of the vehicle economy. With a simple vehicle dynamic model, the fuel economy is calculated to determine the lock-up strategy. Then the lock-up strategy is developed for a slip schedule.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.55-59
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• 1991

This paper deals with the control stratege for the constant voltage, constant frequency(CVCF) generation of doubly-fed induction generator. As an induction machine is a nonlinear and multivariable machine, so, the control system is needed a very sophiticated control processes to meet a CVCF condition. In this paper, control system is constructed and tested using the suggested exitation equation. The test results show that the suggested equation and control system are very useful strategy for the CVCF control of induction generator.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1136-1141
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• 1992

This paper proposes a control technique to obtain high frequency quasi sinusoidal DC-Link waveform permitting zero-voltage-switching(ZVS). This operation results in reduction of commutation stress and switching losses in the power devices because they cause no switching loss in principle. But in existing control methods, the resonant capacitor voltage is not frequently made of zero-cross oscillation. We propose an optimum control stratege which can sustain oscillation and keep the capacitor voltage at an allowable level. Some experimental results are included to confirm the validity of the analytical results.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.125-132
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• 2002

In this paper, a high performance current control strategy for a Brushless DC Motor is presented. The proposed strategy is based on the ramp comparison PI current control with the predictive voltage compensation. The proposed strategy is compared with the hysteresis current control strategy. The proposed method can improve the current waveforms, and it can reduce the torque ripples. So the proposed strategy is suitable to a high performance current control strategy for a Brushless DC Motor. The simulation and experimental results for a laboratory Brushless DC motor drive system confirm the validity of the proposed strategy.

• Spatial Information Research
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• v.5 no.1
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• pp.61-75
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• 1997

National Geographic Information System(NGIS) should be designed on the assumption that geographic data collected by each national organization should be integrated into geographic database systemically. To achieve this object, NGIS database would be better connected to National Very High-Speed Communication Network. In the process of research, some problems related to Korean NGIS are found. These are standardization, compatibility, extension, issue of making and opening digital map, and issue related to land information. So, it is required that pilot project apply National Geographic Information System in terms of National Very High-Speed computer network project. This project is to contain two main theme building of physical network and special management of network which is related with NGIS.