• The Journal of Engineering Research
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• v.7 no.1
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• pp.5-16
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• 2005

We implemented DPGC(Double-Pass Gain-Clamped) L-band EDFA for highly efficient amplification. A lasing signal generated within the linear cavity, can minimize the fluctuation of surviving channels when several WDM(Wavelength Division Multiplexing) channels are added or dropped. The new method describing the characteristics of transient response of surviving channels quantitatively is suggested. It is to measure the ratio of lasing output before add or drop to that after add or drop. We investigated dynamic characteristics by using this method according to lasing wavelengths and propagation directions within the cavity. The experimental measurements show that the short lasing wavelength and backward propagation direction is the best condition for small fluctuation of surviving channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1348-1358
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• 2000

The paper contributes to a traffic analysis for the CDMA cellular base station with repeater which are operated in a cell site. Usually the repeaters' traffic of the CDMA cellular system hardly could be separated from that of the base station because the links of the repeaters are divided from RF circuits of the base station. The paper introduces a traffic measuring method that separates the traffic of repeaters from that of the base station using time delay device. To get general results we use a single BTS(Base station Transceiver Subsystem) with three repeater as well as a single BTS with a single repeater. Then we proved that the traffic of the repeaters could separate from that of the base station clearly.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.10-19
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• 2013

This Paper proposed the development of new magnetic sensor and recognition system to expendite pattern recognition of a handwriting character. Received character graphics should be performed the session and balancing and no extraction of end points, bend points and juntions separately. The Artifical intelligence algorithm is adapted to structure snalysis and recognition process by individual basic letter dictionary except for the handwriing character graphic dictionaryimproving error of recognition algorithm and enomous dictionary for generalization. In this Paper, recognition rate of the received character are compared with pre registered character at letter dictionary for performance test of magnetic ball sensor. As a result of unicode conversion and eomparison, the artificial intelligence study have recognition rate more than 95% at initial recognition rate of 70%.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.15-16
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• 2006

배전선로에 전력을 공급하는 방식은 일반적으로 22.9kV급 XLPE 케이블에 의한 전력공급이 주를 이루어 왔다. 한편으로 대규모 전력을 소비하는 공장 및 고층 빌딩의 전력 공급에 있어서는 일반적으로 각각 부하로의 많은 회선수의 케이블 포설을 요하는 전력케이블 보다는, 한 선로로 보다 많은 대전류를 수송하면서 부하 가까이에서 필요한 전류를 간편하게 분기해 공급받는 부스덕트 시스템이 시공 및 배전선로 관리의 간편성에 의해 점차 용도가 늘어나고 있다. 부스닥트 시스템의 대부분은 일단 시설물이 건축될 때 건축물의 상부 공간 또는 설비가 위치한 하부 바닥 구간을 통해 설치된 이후, 기타 배관, 가스관 등의 추가적인 건축 구조물과 함께 설치되어 이후 선로의 보수 진단 등이 대부분 어렵게 되어진다. 본 논문에서 소개하는 부스덕트의 온도감시 시스템은 아무리 복잡하고 협소한 설치 환경이라도 특수한 포설 공법에 의해 광화이버를 포설하고, 이를 활용하여 실시간으로 부스덕트 선로의 표면온도와 주변온도를 상시 감시함으로써, 효율적인 부스덕트 선로의 활용뿐만 아니라 과열에 의한 절연사고를 미연 방지하는 운전신뢰성과 안정성을 높이는 것이 가능하게 되었다.

• Journal for History of Mathematics
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• v.19 no.2
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• pp.125-140
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• 2006

In 1933, I. Schur introduced a Schur ring in connection with permutation group and regular subgroup. After then, it was studied mostly for purely group theoretical purposes. In 1970s, Klin and Poschel initiated its usage in the investigation of graphs, especially for Cayley and circulant graphs. Nowadays it is known that Schur ring is one of the best way to enumerate Cayley graphs. In this paper we study the origin of Schur ring back to 1933 and keep trace its evolution to graph theory and combinatorics.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.239-245
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• 2019

RISC-V is a free and open ISA enabling a new era of processor innovation through open standard collaboration. Born in academia and research, RISC-V ISA delivers a new level of free, extensible software and hardware freedom on architecture, paving the way for the next 50 years of computing design and innovation. In this paper, according to the emergence of RISC-V architecture, we describe the RISC-V processor instruction set constituted by arithmetic logic, memory, branch, control, status register, environment call and break point instructions. Using ModelSim and Quartus-II, 38 instructions of RISC-V has been successfully simulated and synthesized.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1043-1046
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• 2008

관점 지향 프로그래밍은 구조적 프로그래밍, 객체 지향 프로그래밍 등 기존 프로그래밍 방법론에서 모듈화하지 못한 여러 요구사항에 걸쳐 있는 부가적인 요구사항을 모듈화 할 수 있는 방법을 제공한다. 모듈화 하기 어려운 요구 사항을 횡단 관심으로 분류하고, 이를 애스펙트 단위로 모듈화하여 재사용성을 극대화시키는 관점 지향 프로그래밍은 새로운 프로그래밍 패러다임으로 활발하게 연구가 진행 중이다. 본 논문에서는 현재 비즈니스 및 분산 컴퓨팅 환경에서 많이 이용되는 워크플로우 표준 언어인 BPEL에 워크플로우 서비스의 전이조건의 재사용성을 극대화하기 위해 관점 지향 프로그래밍 기술을 적용한 워크플로우 서비스 시스템을 제안한다. 본 시스템은 기존의 BPEL 엔진을 거의 수정하지 않고 AOP 기법의 적용이 가능하다. 또한, 웹 서비스 분기 및 선택을 위한 서비스 전이 조건으로 요구되는 정보를 실행 도중에 변경하여 웹 서비스 흐름을 재구성할 수 있고, AOP 기법을 이용하여 서비스 전이 조건을 변경하는 모듈을 재사용할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.573-578
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• 2000

This paper presents a noble optical access system using shared laser and LED light sources, which is based on WDM-PON technologies. This system adopts an external modulation of the shared laser sources for high-speed downstream and a direct modulation of the LED sources for low-speed upstream. To split or combine the transmission channels, AWG(Arrayed Wave-guide Grating) devices are used in the optical cable section. The proposed system is attractive for low cost implementation. The laser light sources can share the optical carriers in the downstream scheme. Also, in upstream, the LED sources can afford to make simple of the circuits for controlling light source and of standardization for ONU(Optical Network Unit). The feasibility of the proposed system is demonstrated by several experiments. Our results show that the system operates well at 2.SGbps for downstream and up to 622.08Mbps for upstream.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.31-38
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• 2020

In this paper, we propose a quadruple band antenna for GPS/WLAN/WiMAX application. The proposed antenna has quadruple band characteristics by considering the interconnection of four strip lines and DGS on the ground place. The total substrate size is 20.0 mm (W1) ⨯27.0 mm (L1), thickness (h) 1.0 mm, and the dielectric constant is 4.4, which is made of 20.0 mm (W2)⨯ 27.0 mm (L8 + L6+ L10) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 60 MHz (1.525 to 1.585 GHz) bandwidth for GPS band, 825 MHz (3.31 to 4.135 GHz) bandwidth for WiMAX band and 480 MHz (2.395 to 2.975 GHz) and 385 MHz (5.10 to 5.485 GHz) bandwidth for WLAN band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency of triple band as required.

• Korean Journal of Social Welfare
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• v.55
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• pp.181-204
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• 2003

The purpose of this study was to offer a comprehensive analysis of the changing trends of the Korean income packaging, poverty rate, and level of income inequality from 1996 to 2002. In order to do that, this study used the micro-data of "Income and Expenditure Survey of Urban Households" by the National Statistical Office(NSO). Major results were as follows: (1) A ratio of public transfer in family income packaging increased at the DJ administration. (2) Poverty rate and Gini coefficient, which were 7.8% and 0.29 in 1996, rose to $8.8{\sim}10.4%$ and $0.30{\sim}0.34$ respectively during the year of 1998-2002. (3) However, poverty reduction effect and income inequality reduction effect of public income transfer increased preferably at the DJ administration. Those effects increased more since the enactment of National Basic Livelihood Security in 2000. Therefore, government should provide more national welfare programs to reduce the poverty rate and to improve better structure of income distribution.