• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1551-1558
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• 2007

The standard of evaluating function of speech coder for mobile telecommunication can be shown in channel capacity, noise immunity, encryption, complexity and encoding delay largely. This study is an algorithm to reduce complexity applying to CDMA(Code Division Multiple Access) mobile telecommunication system, which has a benefit of keeping the existing advantage of telecommunication quality and low transmission rate. This paper has an objective to reduce the computing complexity by controlling the frequency band nonuniform during the changing process of LSP(Line Spectrum Pairs) parameters from LPC(Line Predictive Coding) coefficients used for EVRC(Enhanced Variable-Rate Coder, IS-127) speech coders. Its experimental result showed that when comparing the speech coder applied by the proposed algorithm with the existing EVRC speech coder, it's decreased by 45% at average. Also, the values of LSP parameters, Synthetic speech signal and Spectrogram test result were obtained same as the existing method.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.375-380
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• 2004

This paper presents the basic quench protection idea for the HTS(High-Temperature Superconducting) cable. In Korea power system, the transfer capability of transmission line is limited by the voltage stability, and HTS cable could be one of the countermeasure to solve the transfer limit as its higher current capacity and lower impedance[1]. However, the quench characteristic of HTS cable makes HTS cable to loss its superconductivity, and therefore change the impedance of the line and power system operating condition dramatically. This pheonominum threats not only HTS cable safety but also power system security, therefore a proper protection scheme and security control counterplan have to be established before HTS cable implementation. In this paper, the quench characteristics of HTS cable for the fault current based on heat balance equation was established and a proper protection method by FCL(Fault Current Limiter) was suggested.

• 한국전산유체공학회지
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• 제7권2호
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• pp.1-7
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• 2002

The present study is developed device that effectively mixes raw water and chemicals by using the residual head of fluid in the front pipe of flocculation basin, and performed non-dimensional analysis and presented design standard to apply to water plants that have different equipment capacity. The variables for design are a proper ratio between an outer diameter of deflector and a diameter of pipe, a distance between deflector and orifice and a determination of orifice diameter for an optimal mixing. Numerical study has analyzed flow field on a basis of turbulent intensity in an orifice downstream. As Reynolds number of In-Line Orifice was increased from identical design variable, the turbulent intensity of pipe center was no changed almost.

• 산업공학
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• 제5권2호
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• pp.39-52
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• 1992

This paper presents alternatives for facilities planning and analyses them using simulation approach. For this purpose, hydro-cylinder production line was sampled as a case study. Several facilities planning alternatives are evaluated based on the several factors such as line balancing, equipment utilization, optimum number of equipments, inventory size, flow time, bottleneck machine, and productive capacity. An optimal facilities planning is proposed based on the degree of meeting with the all factors evaluated. The simulation language employed in this study is SIMAN and the data used for simulation are provided by hydro-cylinder shop.

• 전기학회논문지
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• 제62권5호
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• pp.632-638
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• 2013

In this study, we described voltage fluctuation characteristics of distribution line during starting and normal operation condition of the small hydro generators. Based on these theories, we scrutinized the starting and operating characteristics of induction generators installed in two small hydro power plants that is connected to the distribution line and researched necessary factors when selecting the generator type. The type of turbines and capacity of generators are different. One is below 1,000kW and the other is above 1,000kW. Two generators are tested during starting, and it acts as motor not generator at the instant that the machine is connected to the grid. After connecting to the grid, the machine rotates above synchronous speed before converting to the generator mode. Therefore the characteristic of the generator during starting is same as it of motor.

• 조명전기설비학회논문지
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• 제25권10호
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• pp.23-27
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• 2011

In this paper, material handing cleanroom stocker system for thin film solar cell line of photovoltaic industry and liquid crystal display line of flat panel display industry was selected for the study. Optimum solution for stocker system's CPS(Contactless Power Supply) is approached by changing the motion pattern, optimizing design & production, and analyzing characteristics of the power system. As a result, acceleration time of X-Axis changed from 3 sec to 4 sec, changed the input characteristic of CPS within approximately 11[kW]. This result shows that extending acceleration time of the X-Axis in Stocker Crane's motion pattern can reduce the capacity of the CPS, thus saving the manufacturing cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.17-19
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• 2005

This paper illustrates the case studies of reliability evaluation for interconnecting power systems in the north east Asia by using the tie line constrained equivalent assisting generator model(TEAG), which has been already developed in the second project year. A reliability evaluation program, it is named, NEAREL. based on the TEAS model was made. The reliability evaluation results for the seven interconnection scenarios of the actual power systems of six countries in the north east Asia are introduced and compared. The reasonable capacity of the tie line for three countries interconnection senario is suggested from sensitivity analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.31-33
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• 2000

This paper discusses the operational characteristic analysis of distance relay depending on the power system parameters in transmission line including FACTS devices. Distance relay requires protective coordination because the FACTS devices change power system parameters to increase power transmission capacity. In this paper, the dynamic operational characteristics of distance relay are analyed for the effect of fault resistance and operation mode of FACTS devices according to the installed points of these devices.

• 한국철도학회논문집
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• 제9권2호
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• pp.222-229
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• 2006

Recently, the development of the paved track is required as a low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The important factors of paved track are stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the prepacked concrete technique. The most important thing to design the paved track is to optimize the track structure considering various conditions. Because construction environment is very limited, cost is expensive and it has very complicated behavior. On this paper, structural characteristics of the paved track are investigated using the 3D finite element analysis to verify the optimized structure of the CMP track.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.156-158
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• 2000

As we are industrialized lately, power capacity is increased in the city urban areas. So the application of underground transmission line is largely expended. In this paper, we analysis the induction voltage on the sheath of 1,200[$mm^2$] OF underground cable being used 154kV underground transmission line. If the current on the cable conductor is 300[A], circulation current is induced the maximum 100[A] on the cable sheath.