색각 능력의 정량적 평가를 위한 전산화된 다중 15-색상 배열 검사법

고성택,홍성철,최민주,Ko S.T.,Hong S.C.,Choi M.J. 대한의용생체공학회 2000 의공학회지 Vol.21 No.3

색상 배열 검사법은 기준 색편을 시작으로 다수의 색편을 가장 유사한 것들로 서로 인접하게 배열하도록 하여 피검사자의 색각 능력 (색력)을 평가하는 방법이다. 본 논문에서는 색각 능력을 신속히, 정량적으로 평가하기 위한 다중 15-색상 배열 검사법을 구성하여 PC에 구현하였다. 검사의 난이도는 인접한 색편간의 색상 차 (CDBACC: color difference between adjacent color chips)의 크기로 조정하였다. CDBACC는 국제조명 위원회에서 추천한 식을 사용하여 계산하였다. 본 연구에서는 CDBACC가 0.75, 1.1. 1.8, 2.5. 3.5, 7.5. 11, 14의 값을 가지는 8단계 난이도의 색상 배열 검사법 (test 3-10)과 빨강, 녹색, 청색의 채도 변화를 등간격으로 분할하여 15 개의 색편을 구성한 3 가지 기본색 배열 검사법(test 11(R), 12(G), 13(B))을 설계하였다. PC에 구현된 다중 15-색상 배열 검사의 평가를 위해 이시하라식 검사법으로 색맹인 아닌 30 명을 대상으로 실험을 수행하였다. 실험 결과 피검사자의 색상 배열 정확도는 CDBACC가 2 - 4.5인 영역에서 급격히 변하고 있으며, CDBACC 값이 5 이상에서는 대부분의 피검사자들이 오차 없이 색편을 배열한 반면, 2 이하에서는 아무도 정확히 색편을 배열하지 못한 것으로 나타났다. 기본색배열 검사 (CDBACC : 6.87. 7.27. 7.86)에서는 CDBACC가 5 이상임에도 불구하고 색편 배열에 대한 매우 낮은 정확도를 보였다. 색력의 척도라 할 수 있는 피검사자의 색편 배열 정확도가 급격히 변화하는 검사의 색상 차의 평균값은 3으로 나타났으며, 이때의 ERCCA (error rate of color chips arrangement)은 $20\%$로 나타났다. 븐 연구에서 PC에 구현한 다중 15-색상 배열 검사법은 피검사자의 색각 능력을 신속히 세밀하게 정량적으로 평가하는 경제적인 도구로 사용될 것으로 기대하며, 향후 후천성 색각 이상을 유발하는 질환 (예 diabetes, glaucoma)을 집단 검진하는데 유용하게 활용될 수 있을 것으로 기대된다. Multiple 15-hue tests were designed and implemented on a PC in the study so as to quickly and quantitatively evaluate color vision acuity. Difficulty of the test was control)ed by the value of CDBACC (color difference between adjacent color chips) calculated using a CIELAB formula. The multiple 15-hue tests consist of eight of the hue tests (test 3-10) and three of the basic color (red, green, blue) tests (test 11-13). The 15 colors used for the hue tests were specified by the 15 color coordinates that were located at a constant distance (d = 2. 3. 5. 7, 10, 20, 30. 40) from white reference in the CIE chromaticity coordinate system and were separated by a constant color difference (CDBACC = 0.75, 1.1, 1.8. 2.5. 3.5. 7.5. 11, 14) from the adjacent chips. The color coordinates for the 15 chips for the basic color tests were the same as those of the 15 points spaced equally by a constant color difference (6.87 for the green color test. 7.27 for the red color test, 7.86 for the blue color test) from the white reference along the axis of red, green and blue. Thirty normal subjects who were not color blind were taken to undergo the multiple 15-hue tests. It was observed that most of the subjects correctly arranged color chips for the tests with CDBACC greater than 5, whereas no one correctly answered for those with CDBACC less than 2. Rapid changes in the number of the subjects correctly arranged took place when CDBACC of the tests was between 2 and 4.5. In the basic color tests, unlike the hue tests having similar values of CDBACC, it was seen that the subjects arranged color chips even less correctly. It was found that JNCD (just noticeable color difference) - a measure of color vision acuity was about 3 in average for the subjects. The JNCD was chosen as the value of the CDBACC of the test for which about $50\%$ of the subjects failed to successfully arrange color chips. ERCCA (error rate of color chips arrangement) for the test with CDBACC the same as the JNCD was shown to be about $20\%$. It is expected that the multi 15-hue tests implemented on a PC in the study will be an economical tool to quickly and quantitatively evaluate color vision acuity and, accordingly, the tests can be used for early diagnosis to massive potential patients suffering from diseases (ex. diabetes, glaucoma) which may induce changes in color vision acuity.

An Optically Controlled Bistable Semiconductor Switch

고성택 한국통신학회 1991 한국통신학회 학술대회논문집 Vol.10 No.2

광제어 쌍안정 반도체 스위치에서 구리 불순물이 스위치특성에 미치는 영향

고성택 한국전기전자재료학회 1994 電氣電子材料學會誌 Vol.7 No.3

Cu compensated Si doped GaAs (GaAs :Si:Cu has been chosen as the switch material. The GaAs material has been characterized by DLTS(Deep Level Transient Spectroscopy) technique and the obtained data were used in the computer simulation. Simulation studies are performed on several GaAs switch systems, composed of different densities of Cu, to investigate the influence of deep traps in the switch systems. The computed results demonstrates important aspect of the switch, the existence of two stable states and fast optical quenching. An important parameter optimum Cu density for the switch are also determined.

벌크 GaAs 반도체의 광 스위칭 특성

고성택,강민제,조경호 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.2

A model for a gallium arsenide(GaAs:Si:Cu) photoconductive switch has been developed and solved to determine the performance of the device in bistable switch applications. Simulation studies are performed on a GaAs switch system composed of different density of deep levels to investigate the influence of deep traps in a photoconductive switch system. The computer results show that the initial electron occupation at the deep accepters controls the on-state conductivity of the switch. The required photon flux to turn off the switch is obtained from the computer simulation.

ATM망의 가상경로 상에서 효율적인 대역관리

고성택,김경식,김경연,최영복,고승일 濟州大學校工科大學産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.2

ATM(asynchronous transfer mode) is able to realize the full integration of various kinds of services. Effective bandwidth allocations using statistical multiplexing gain haute been studied for the full integration of different kinds of services. In this paper. we present call admission control algorithm using complete bandwidth sharing and reserved bandwidth sharing. Complete bandwidth sharing is an efficient way for utilization of bandwidth. Reserved bandwidth sharing is an efficient way for preventing reverse pecking order. Using these two bandwidth allocations is an effective way for bandwidth utilization and stopping reverse pecking order. A computer simulation shows the results of the algorithm.

Numerical Analysis for the Optically Controlled Bistable Semiconductor Switches

Ko, Sung-Taek 제주대학교 1991 논문집 Vol.33 No.-

Si이 도핑된 후 Cu로 보상된 GaAs가 스위치 물질로 선택되었다. Deep 불순물들이 스위치 시스템에 미치는 영향을 조사하기 위해 여러가지 농도로 도핑된 GaAs 스위치 시스템에 대해서 콤퓨터 씨뮬레이션이 수행되었다. 콤퓨터에 의해 계산된 결과는 스위치에 대한 다음의 두가지 중요한 양상을 보여주고 있다. 즉 안정되고 높은 전도의 상태(도통상태)와 빠른 빛에 의한 캐리어의 소거(차단상태)를 보여준다. 또한 스위치에 대한 중요한 파라메터인 최적의 Cu 농도와 높은 전도상태의 포화 조건 등이 결정되었다. Cu compensated Si doped GaAs(GaAs:Si:Cu) has been chosen as the switch material. Simulation studies are performed on several GaAS switch systems, composed of different densities of Cu, to investigate the influence of deep traps in the switch systems. The computed results demonstrates important aspect of the switch, the existence of stable high conductivity (on-state) and fast optical quenching (turn-off). Some important parameters such as high conductivity saturation and optimum Cu density for the switch are determined.

실리콘 미세가공 기술을 이용한 마이크로 진공 센서

이광만,고성택,김영민,고희선 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.1

A micro-vacuum sensor has been fabricated by using silicon micromachining techniques and platinum thin film. NON insulator was deposited by LPCVD and APCVD methods. The insulator diaphragm was fabricated by silicon anisotropic etching in TMAH solution. Thin film platinum heater and temperature detector were deposited by rf sputtering method and patterning was performed by means of lift-off method. Deposited platinum heater and temperature detector have been shown a linear I-V characteristics. TCR( temperature coefficient of resistance) of thin film platinum heater and temperature detector was about 0.0042/℃. Fabricated vacuum sensor was measured in the range of 1X 10^(-3) Torr to 1X10^(2) Torr. and shows a good linear operating characteristics in the range of 1x1^(-2) Torr에서 1X10^(0) Torr.

광 교환 기술을 이용한 ATM 백본 네트워크

최영복,고성택,김경연,김경식 濟州大學校 工科大學 産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.2

The B-ISDN(Broadband-Integrated Service Digital Network) transports various multimedia information effectively. So optical switching networks which consist of optical transmission links and photonic switching systems are noticeable as a way of a large capacity communication. In this paper, we propose optical packet switching networks which will be used as the backbone network of national high speed communication networks which are operated a way of ATM(Asynchronous Transfer Mode). The B-ISDN transport networks are composed of two-layered networks such as regional networks and a backbone network. The regional network is an average ATM transport network. The optical backbone network gathers fixed length of several ATM cells which come from regional networks, attaches an optical header, and completes an optical packet. And then the network switches and transports with high speed. That is, the backbone network is a transparent optical packet network. The passing speed of signal in the photonic switch is rapid, but the switching speed is limited and the processing speed of the switching controller which consists of electronic circuit is limited. So the optical packet which consists of multi-ATM cells is able to overcome it in the optical backbone network. The performance evaluation by the computer simulation shows us the efficiency of the proposed way of optical packet switching.

ATM망의 가상경로 상에서 효율적인 대역관리

고승일,고성택,김경식,김경연,최영복 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.2

ATM(asynchronous transfer mode) is able to realize the full integration of various kinds of services. Effective bandwidth allocations using statistical multiplexing gain have been studied for the full integration of different kinds of services. In this paper. we present call admission control algorithm using complete bandwidth sharing and reserved bandwidth sharing. Complete bandwidth sharing is an efficient way for utilization of bandwidth. Reserved bandwidth sharing is an efficient way for preventing reverse pecking order. Using these two bandwidth allocations is an effective way for bandwidth utilization and stopping reverse pecking order. A computer simulation shows the results of the algorithm

ATM망에서 효율적인 문턱 값 기반 호 수락 제어

김상철,고성택,Kim Sang Chul,Ko Sung-Taek 한국융합신호처리학회 2000 융합신호처리학회 논문지 (JISPS) Vol.1 No.2

ATM 트래픽 제어를 위해서 효과적인 호 수락 제어 방법이 필요하다. 이것은 호 수락 과정에서 서로 다른 종류의 서비스들에 대해서 높은 이용률과 공정성을 제공하여야 한다. 전체 대역공유 법은 대역폭 이용률 측면에서는 효율적이지만 호 수락의 공정성 측면에서는 비효율적이다. 전체 대역 분할 할당 법은 공정성 측면에서는 효율적이지만 대역폭 이용률 측면에서는 비효율적이다. 본 논문에서는 호 수락의 공정성과 대역폭 이용률을 높이기 위하여 링크에 문턱 값을 적용한 새로운 CST(Complete Sharing with Threshold) 알고리즘을 제안하였다.