• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.252-255
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• 2008

A study for discharge pattern analysis partial and fault location by use of UHF sensors in GIS. However, in the latter case, the results considered the velocity of EM waves modified by the waveguide characteristics of GIS bus bar were not reported yet. In this paper, UHF wide band sensor to detect partial discharge signals have been designed and manufactured to get the widest band characteristic by an application of Fat-Dipole UHF antenna and the result that the transmission velocity of EM waves is 2/3 of the light have been got through the consideration of waveguide characteristics. Also, to verify applicability on site of the developed method, self-designed external type UHF sensor have been installed on operating GIS in Korea Midland Power co. and detected location of the fault. Through the fault have been found at the location, the reliability of the developed method have been proved.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.420-422
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• 2007

Nowadays, the demand for home networking system is gradually increasing. But most of vendors use their own protocols. KNX/EIB ( European Installation Bus / Konnex) is a standard protocol approved as an European (EN 50090 - EN 13321-1) and a World-wide standard (ISO/IEC 14543). In this study, we develop on/off and dimming lighting control system using BIM. In this system, BIM communicates to micro-controller using PEI(Physical External Interface) communication. And this enables including more KNX/EIB communication objects in lighting control system, and providing lighting control algorithm. The technology in this paper can help to adapt the world-wide standards.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.87-90
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• 2006

Nowadays, we can enjoy access to high speed network and advanced services of convergence between broadcasting and communication anywhere and anytime through a ubiquitous computing. So, now digital convergence devices come out constantly. These devices are required faster network environment for high speed data processing than before. In this paper, we describe the design of InfiniBnad network adapter, which is included two FPGA chipsets. When this adapter is installed to Digital Convergence Platform (DCP) network performance will be improved. The adapter includes 12channel serial ports for external communication and internally, uses PCI-Express bus. We have finished the test of high speed serial based network adapter through composing complete InfiniBand network and applied fabric management software. So, we have verified that it can be applied on DCP environment.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.439-442
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• 2009

As a result of increasing environmental concern, the penetration of renewable power on power systems is now increasing. Wind energy can be considered as the most economical energy sources to generate electricity without depletion of fossil fuel. The penetration of wind energy from wind farm is getting larger and larger, so we need adequate control strategies for wind farm. To devise adequate control strategies for wind farm, time domain simulation analysis needs to be performed. This presents a Simultaneous Implicit-based time domain simulation algorithm for wind farm with DFAG (Doubly Fed Asynchronous generator) connected to the external power systems. This paper shows an illustrative example with a 5-bus test system.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.12
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• pp.9-19
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• 1997

This paper describes the design and FPGA implementation of a system control unit within a multiprocessor chip which can be used as a node processor ina massively parallel processing (MPP) caches, memory management units, a bus unit and a system control unit. Major functions of the system control unit are locking/unlocking of the shared variables of protected access, synchronization of instruction execution among four integer untis, control of interrupts, generation control of processor's status, etc. The system control unit was modeled in very high level using verilog HDL. Then, it was simulated and verified in an environment where trap handler and external interrupt controller were added. Functional blocks of the system control unit were changed into RTL(register transfer level) model and synthesized using xilinx FPGA cell library in synopsys tool. The synthesized system control unit was implemented by Xilinx FPGA chip (XC4025EPG299) after timing verification.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.6-11
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• 2004

CNG buses were introduced in 2002 to reduce air pollution to the big cities. The durability and safety evaluation were performed for the NGV-2 type cylinders taken from two buses after 30 months of running. No external damage and no internal corrosion was observed on the container surfaces. Defect exceeding the allowable limit was not found in the UT test. Permanent volume expansion was about 1.2% which is much smaller than the required design limit. Cycling test showed no failure after 11,250cycles and burst pressures were still above the maximum design pressure. Both the longitudinal and circumferential failure mode were observed, where both the fracture strengths were far above the design limit. This study showed the present CNG fuel cylinders were safe enough for further usage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.55-63
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• 2016

SOA(service oriented architecture) based ESB(enterprise service bus) model is widely adopted in many companies for the safe processing of enormous data and the integration of business system. The existing web service technologies for the construction of SOA, however, show unsatisfactory in practical applications though the standardization of web service security technologies is in progress due to their limitations in safe exchange of data. Internal end users using a large business system based on such environment are composed of the variety of organizations and roles. Companies might receive more serious damage from insider threat than that from external one when internal end users get unauthorized information beyond the limits of their authority for private profit and bad purposes. In this paper, we propose a security architecture capable of identifying and coping with the security threats of web service technologies arouse from internal end users.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.2
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• pp.12-22
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• 1991

The purpose of this study is to identify demand and methods of projection, including to prove the variables affecting the fluctuation of visitors and to analyze the relationship between these variables in National Park. Statistical analysis method (Multiple Linear Regression Analysis, ANOVA, and Model diagnostics) was carried out by computer program SAS/pc. 13 variables (1. Total Population, 2. Per Capita PDI, 3. Employment Ratio of S.O.C. & others, 4. NO. of Passenger Car, 5. Length of Roads, 6. Leisure Expenditure of Farm Household, 7. Leisure Expenditure of Urban Household, 8. Price Index, 9. NO. of Bus, 10. Exchange on Dollars, 11. Export, 12. Import, and 13. Visitors in National Park) had been used to this study. The scope of time period is during the last 17 years (1970-1986). The results were as follows; 1) Participation depends only on the specific characteristics of the economic factors (Price Index and Leisure Expenditure of Urban Household). These factors are the importance factors directly affecting the participation of visitors. The statistical Model for projecting the visitors in National Parks is the function of "Visitors in National Parks (thousand)=14915+0.210311*Leisure Expenditure of Urband Household (won)-157.835619*Price Index(1985=100)" 2) The external factors affecting the participation depends upon the interelated features of availability and accessibility (NO. of Passenger Car, Length of Roads, and NO. of Bus) of recreation resources or sites, and the economic factors (Per Capita PDI, Export, and Import). These factors are the factors indirectly affecting the participation of visitors. 3) The participation depends on the specific characteristics of demographic factors (Total Population and Employment Ratio of S.O.C. & others). These factors are the factors indirectly affecting the participation of visitors. 4) The unexpected fluctuation of yearly visitors depends on oil shock or inflation (1971, 1973-1974, 1979-1980), promulgation of national emergency decrees (1971-1972, 1974-1975, 1979-1980), and national events (assassination of president Park's wife, Madame Yuk in 1974 and president Park I 1979).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.15-19
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• 2001

This paper presents an modelling and analysis of SSSC and UPFC in static analysis of power systems. SSSC is used to control active power flow in transmission lines by controlling the phase angle of the injected voltage source which is in rectangular to the line current. UPEC is used to control the magnitude and phase of the injected voltage sources which are connected both in series and in parallel with the transmission line to control power flow and bus voltage. To compare the effect of SSSC and UPFC in power system static analysis, the PSS/E simulation program is used. As the FACTS device model such as SSSC and UPFC is not provided in PSS/E yet, an equivalent load model is used. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to improve bus voltage than SSSC in power system static analysis.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.115-123
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• 2011

This study was conducted to investigate the early-age behavior and performance of precast pavements constructed by replacing existing asphalt pavements for an intersection in urban bus only lanes. The monitoring items included level differences between asphalt pavement and precast panels at the beginning and ending locations of the precast pavement, level differences and joint widths between precast panels, precast panel settlement, and skid resistance of the panel surface. At a certain time after the construction, the diamond grinding method was applied and its effect was also investigated. The monitoring results showed that as time went by, the panel level, joint width, settlement, and skid resistance were not much varied. That implied the stable sustaining of external loads by the precast pavements. In addition, it was verified that employing diamond grinding could reduce the level differences between precast panels.