• Proceedings of the KSR Conference
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• 2011.05a
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• pp.652-659
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• 2011

Due to overuse of commercial network systems such as bluetooth and WI-FI, the problems of frequency interruption and line-crossing may arise. For this reason, wireless communication frequency ISM 2.4GHz, a recently adapted concept in Korea which is employeed by RF-CBTC system, is predicted not to have guarantee for outstanding and continuous performance. Therefore in this study, considering these problems, 5GHz capacity wireless Lans with international standard 802.11a/b/g applied were installed in the underground urban transit areas and it was proved that these lans exceeded the performance level of 2.4GHz with international standard 802.11b which is being introduced in the nation. In addition, it was verified through carrying out an application test that the communication condition was stable in a running train with high speed in the tunnel.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1364-1371
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• 2011

Advanced EMU completed a production of test train, composed of 6 cars, after 5 years of development process, and it is currently under the process of integrated test and evaluation to inspect performance of car system, efficiency of transport, safety, punctuality, energy efficiency in accordance with urban railways act at Daebul test line. Advanced EMU was produced under consideration of transportation capacity, maintainability, reliability, energy saving, convenience of passengers, and traffic-vulnerables, so it has an epochal difference from former EMU system. And advanced EMU assures operation management from manager's perspective and efficiency of maintenance for practicalization of car and individual equipment. This paper introduces each major equipment of advanced EMU which is based on many years of experience of management and maintenance.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.637-640
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• 2002

The deterioration of RC deck slabs has been a serious problem and high portion of budget has been a spent for repair and strengthening of deck slab. The concrete deck slabs are subject to direct application of vehicle loading and accumulation of fatigue damage. Besides, various environmental causes. In this paper, an probabilistic study is carried out to predict exact load effects and structural capacity of deck slab during its service life, and estimate an appropriate remaining life of deck slab. To achieve this purpose the live load model is developed using by influence line including deterioration of deck slab, and deterioration model of bridge deck slab is developed. In addition, the fatigue life of reinforced concrete deck slabs considering corrosion of reinforcement are estimated based on experimental formula. This study will help rational decisions for the management and repair of reinforced concrete deck slabs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.286-286
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• 2009

According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Moreover, the defects have been limited power capacity of transmission line. This paper study on mechanical and thermal behavior of ACSR $410mm^2$ conductor and sleeve with various defect model. The conductor has been aged artificially for 50 years. The detailed results were presented in the text.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1485-1488
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• 1997

The capacity of memory chip has increased vert quickly and 64MDRAM becomes main product in semiconductor manufacturing lines consists of many sequential processes, including etching process. although it needs direct sensing of wafer state for the accurae detching, it depends on indirect esnsing and sample test because of the complexity of the plasma etching. This equipment receives the inner light of etch chamber through the viewport and convets it to the voltage inetnsity. In this paper, EDP voltage signal has a new role to detect etching failure. First, we gathered data(EPD sigal, etching time and etchrate) and then analyzed the relationships between the signal variatin and the etch rate using two neural network modeling. These methods enable to predict whether ething state is good or not per wafer. For experiments, it is used High Density Inductive coupled Plasma(HDICP) ethcing equipment. Experiments and results proved to be abled to determine the etching state of wafer on-line and analyze the causes by modeling and EPD signal data.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.211-214
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• 1997

This paper applies fuzzy self-tuning PID controller in DS/CDMA cellular system. Power control is essential in DS/CDMA to compensate for the differing received powers due to both the slowly varying long-term and fast varying short-term fading processes and co-channel interference. The controller proposed is adaptable for the variations of the system dynamics and especially for the variable time delay which exists in mobile radio systems. Accordingly the results is the smaller power control error, that is, the smaller average transmitting power of mobile compared with the conventional control schemes. Because interferences to the other mobiles are reduced, the capacity of CDMA can be increased.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1720-1723
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• 2003

Recently, as the road capacity reaches a limit and environmental problems becomes serious, there exists a gradually increased need for railway vehicles that are environment-friendly, punctual, reliable and safe. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. Korean High Speed Train has been developed for last 6 years to satisfy the need. Authors developed a measurement system for on-line test and evaluation of performances of Korean High-Speed Train. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the measurement system. By using the system, measurement and evaluation of the mechanical characteristics of motors and main transformers in Korean High Speed Train was conducted during test running. The measured results for the temperature characteristics of electric devices verify that the measurement system is accurate and reliable.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.445-452
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• 2004

Intermittent deep draw artificial circulation system is one of the most widely used destratification systems to control algal bloom in reservoirs in Korea. However, there have been neither theoretical background of design criteria nor operation guide line for efficient application of the system available for such systems. A design method was developed to calculate required compressor capacity and number of circulation units considering physical interactions between stratified water layers and plumes induced by the intermittent deep draw artificial circulation system. The program was tested with data observed in Yeoncho Lake. The results indicated that the developed method can applied in the fields successfully. Further validation processes would improve design and operation methods.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.57-61
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• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier and large filter capacitor connected with DC line terminal. Due to the large capacity of the capacitor, the charged time of capacitor is very short from the AC source. Lead to the bridge rectifiers draws pulsating current from the AC source side, which results in reduction of power factor and low system efficiency. Therefore a novel single-phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor with a novel switching topology. The proposed drive circuit consists of one switching part and diode, which can separate the output of AC/DC rectifier from the large capacitor and supply power to SRM alternately, in order to realize the torque ripple reduction and power factor improvement through the switching scheme. In addition, the validity of the proposed method is tested by some simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.12
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• pp.594-602
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• 1986

This paper proposes an effective algorithm for short-term generation scheduling for the purpose of economic and secure operation of thermal power systems. Especially, in the procedure of solution by Dynamic Programming, Linear Programming is introduced to promote the possibility of optimal solution and the security of power systems, and evaluation of security function is improved by the application of seven step approximation of normal distribution. Several necessary considerations, that is, time dependent start-up and constant down cost of generating units, demand and spinning reserve constraints, minimum up and sown time constraints, the number of possible start-up of a generating unit in a d and the number of generating units which can be started up at the same time at the same bus, are also incoporated to elevate the usability and flexibility of the algorithm. Finally, the effectiveness of the proposed algorithm has been demonstrated by applying to the 6-gen. 21-bus model power system.