디지털 위성방송수신기용 중간주파수 선정 ( Consideration of the Intermediate Frequency for Digital DBS Receiver )

김영완 대한전자공학회 1995 대한전자공학회 학술대회 Vol.1995 No.11

Ka 대역 초고속 위성통신 시스템에 대한 군지연 및 비선형 특성의 영향

김영완,박동철 한국전자파학회 2001 한국전자파학회논문지 Vol.12 No.4

본 논문에서는 초고속 위성통신 시스템의 채널 특성에 대한 성능 분석을 하였다. 고속 데이터 전송의 열화요인으로 작용하는 군지연과 비선형 분석을 통하여 다양한 전송 서비스를 제공하는 Ka 대역의 초고속 전송 시스템의 채널 성능 영향을 고찰하였다. 전송 데이터가 증가할수록 군지연과 비선형에 의한 영향은 증가하며, 군지연 선형 성분과 비선형의 AM-AM 성분이 시스템 성능 열화에 지배적으로 작용하는 것을 알 수 있었다. 고속 데이터에 따른 광대역 전송 대역폭으로 낮은 군지연과 이득 평탄도를 얻기가 어려우므로 주요 열화 요소를 등화하여 수십 Mbps에서부터 수백 Mbps 의 넓은 범위의 서비스를 동일 시스템에서 효과적으로 제공하여야 한다. 분석된 결과는 최적의 동작점을 갖는 초고속 위성통신 시스템을 설계하고 운용하는데 활용될 수 있다. The effects of group delay and non-linear characteristics on high data rate(HDR) satellite channel are presented in this paper Based on the modeling of group delay and non-linear characteristics the system performances which provide various data rate services were analyzed in Ka-band satellite channel. As the transmission data rate is increased, the degradation due to these channel characteristics is severely increased. The linear component of group delay and the AM-AM component of non-linear characteristics severely affect the system performance. To efficiently provide the various service via the same transmission system it is necessary to equalize the primary impairment factors. The optimum operating points of HDR satellite transmission system are implemented by considering the analyzed results on channel characteristics.

채플의 패러다임 변화를 통한 선교의 극대화 방안

김영완 한국대학선교학회 2009 대학과 선교 Vol.16 No.-

Christian schools in Korea often face a crisis regarding chapel service because most students are non-Christians. But another important contributing factor in this crisis originates from the fact that the traditional service style has not changed in spite of the changes in age, culture and listeners. It is the purpose of this research to maximize missions by changing the paradigm of the chapel. First of all, we need to clearly understand the concept and goal of chapel for this research, because we can not search for a proper method without an accurate understanding of the essence of chapel. According to the origin of chapel, the concept of chapel should be distinguished from that of traditional worship. In particular, chapel should be recognized today as a meeting for the purpose of missions, not for public worship. The purpose of chapel then should be realized in holistic missions including evangelism and education as a social responsibility. Therefore we have to pursue a paradigm shift in chapel, in order that it should be managed for the purpose of holistic missions. Postmodernism has introduced variety to the 21th century and has introduced change to the culture and the audience in all aspects, and thus chapel requires a paradigm shift. Its actual management then should be accompanied not only with the analysis of its audience, but also a cultural-anthropological understanding and approach. Now, the cultural relativism, if the biblical absolutism is not exclusive, is also necessary for the effective management of chapel, while the chapel as traditional worship in the past was managed through ethnocentrism. In addition, the method in which chapel is run should be diversified as well, in order to overcome the crisis of postmodernism, to keep the identity of the christian school, and to maximize missions for the schools. 한국의 기독교학교들은 채플에 대한 반대로 인하여 종종 위기를 겪는다. 이는 채플의 청중 대다수가 비(非)기독교인 학생들이기 때문만이 아니다. 보다 중요한 이유는, 시대와 문화와 청중이 다양하게 변화하였음에도 불구하고, 채플 운영이 여전히 과거의 전통적 예배 방식에서 벗어나지 못하고, 채플의 패러다임 변화를 적절하게 모색하지 못했기 때문이다. 본 연구의 목적은 채플의 패러다임 변화를 통한 선교의 극대화 방안을 모색하는데 있다. 이를 위해서는 먼저 채플의 개념과 목적에 대한 명확한 이해가 선행되어야 한다. 왜냐하면 본질에 대한 명확한 이해가 없이는 올바른 방안을 모색할 수 없기 때문이다. 채플의 유래를 살펴보면 채플의 개념은 전통적 예배의 개념과 구별되어야 한다. 특히 오늘날 기독교학교의 채플은 공적인 예배가 아니라 선교를 목적으로 하는 집회로 이해되어야 한다. 또한 채플은 복음전도와 사회참여로서의 교육이라는 통전적 선교의 목적을 가지고 있다. 따라서 채플은 통전적 선교의 방편으로 운영되어야 하며, 이러한 목적에 따라 채플의 패러다임 변화를 모색해야 한다. 21세기를 주도하는 포스트모더니즘의 대표적 경향인 다양성은 시대와 문화와 청중의 다양한 변화를 가져왔으며, 이는 채플의 패러다임 변화를 요구하고 있다. 따라서 채플 운영은 반드시 청중에 대한 분석과 아울러 청중에 대한 문화인류학적 이해와 접근으로 이루어져야 한다. 과거의 전통적 예배 방식의 채플이 자문화중심주의의 방식이었다면, 이제는 성경적 절대주의의 범위를 벗어나지 않으면서, 문화상대주의의 방식으로 채플 운영이 이루어져야 한다. 뿐만 아니라 채플 운영방식을 다양화함으로써, 포스트모더니즘 시대의 위기를 슬기롭게 극복하고, 기독교학교의 정체성을 지키며, 학원선교의 극대화를 이루도록 해야 한다.

아파트에서 고체음의 부파성상에 관한 연구

김영완,박병진 한국음향학회 1986 韓國音響學會誌 Vol.5 No.4

This pater is a study on the measurement of solid-borne sound propagation in buildings. The purpose of this paper is to present the data needed for comfortable building enevironment. Solid-Borne sound in apartment building was measured at the source of sound and at many receiving locations in building. Dispersion of the sound level was analyzed to understand noises level at different locations. Graphic method as well as polynomial regression techniques were employed. For this experiment, we made use of the TAPPING MACHINE according to the standard rules of ISO as a impulse exciter, and the measurement was carried out after the building has been all completed. Noticeable noise reductions were observed as the distance from the source to the receiving location increases.

이동형 위성통신 서비스를 위한 시스템 위상 잡음

김영완,Kim Young-wan 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.8

디지털 신호의 전송 성능은 전송 시스템의 위상 에러에 지배적으로 영향을 받고 있으며, 위상 에러는 랜덤 특성을 갖는 위상 잡음과 도플러에 의한 추적 위상 에러에 의해 발생된다. 도플러 현상이 나타나는 움직임을 갖는 이동형 위성통신 시스템에서는 랜덤 위상 잡음과 추적 위상 오차에 의한 전송 신호의 영향을 해석하여 이동형 위성통신 시스템에 적합한 시스템 요구 위상 잡음 스펙트럼을 설계해야 한다. 본 논문에서는 이동형 양방향 위성통신 시스템의 비대칭 이동 서비스에 대한 도플러 영향과 위상 에러를 해석하여 요구되는 전송 시스템의 위상 잡음 스펙트럼을 설계하고, 움직임을 갖는 단말국의 도플러 영향을 최소화하는 전송서비스를 해석한다. 제안한 위상 잡음 스펙트럼은 요구 전송 시스템에 대한 주파수 발생 부 주파수 특성으로 설계할 수 있다. The phase error generated in the transmission system affects the performance of digital transmission signal. The phase error are generated by random phase noise and tracking phase error due to denier phenomenon. In the mobile satellite communication system that generates the doppler frequency, which is a system with a movement, the proper system phase noise spectrum should be designed based on analyses for phase noise and static phase error effects. Based on the analyses of the doppler frequency and the phase error for bilateral satellite communication system providing an asynchronous service, the phase noise spectrums for the mobile satellite communication are designed in this paper. Also, the available transmission services under the less doppler effect are proposed and the proper signal source units for a required transmission system can be designed under the proposed system phase noise spectrum.

역 위상 기법과 Aperture를 갖는 개방형 루프 공진기를 사용한 광대역 IF 모듈 설계 및 제작

김영완 대한전자공학회 2004 電子工學會論文誌-TC (Telecommunications) Vol.41 No.11

본 논문에서는 전 디지털 모뎀의 기저 대역 전송 신호를 IF 출력 신호로 주파수 변환하는 모듈에서 발생하는 국부발진 누설 신호를 역 위상 기법을 사용하여 제거하고, aperture 개방형 루프 공진기로 구성되는 광대역 필터를 구성하여 낮은 군지연과 높은 대역 제한 특성을 갖는 광대역 IF 인터페이스 모듈을 설계하고 제작하였다. 45 Mbps 및 155 Mbps 전 디지털 모뎀을 위한 광대역 IFIU는 전송 대역과 밀접하여 간섭 신호로 작용하는 국부발진 신호의 누설 신호를 -60 dBc 이하로 억압하였으며, 각각의 전송율에 대한 IFIU의 군 지연은 15 ns와 8 ns의 낮은 특성으로 구현하였다. L-대역 중심 주파수와 150 MHz 대역통과 특성을 갖는 모듈의 이득 평탄도는 2 dB 이내의 특성으로 광대역 위성통신 시스템 전송에 필요한 요구 조건을 만족하였다. The implementation and design of the wideband IFIU using aperture open loop resonator and reversed phase technique to reduce the local oscillator leakage signal was represented in this paper. The local oscillator leakage signal is generated in stage of frequency conversion, especially in frequency conversion of fully digital modulation signal close to DC signal. The leakage signal and spurious signals, which have effects on adjacent channel or in-band channel as interference signals, were reduced below -60 dBc for 45 Mbps and 155 Mbps IF interface units. The group delay for both IFIUs shows low ripple characteristics of 15 ns and 8 ns, respectively. Also, the amplitude ripple characteristic in 150 MHz bandwidth with L-band center frequency satisfies the required specification of 2 dB. The implemented IFIU provides the required specifications for wideband satellite communication system.

링보강 복합재료 원통셸의 과도해석

김영완,Kim, Yeong-Wan 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.11

The theoretical method is developed to investigate the effects of ring stiffeners on free vibration characteristics and transient response for the ring stiffened composite cylindrical shells subjected to the impulse pressure Loading. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect is adopted to formulate the theoretical model. The concentric or eccentric ring stiffeners are laminated with composite and have the uniform rectangular cross section. The modal analysis technique is used to develop the analytical solutions of the transient problem. The analysis is based on an expansion of the loads, displacements in the double Fourier series that satisfy the boundary conditions. The effect of stiffener's eccentricity, number, size, and position on transient response of the shells is examined. The results are verified by comparison with FEM results.

불균질 매질에서 탄성파 모델링

김영완,장성형,윤왕중,Kim, Young-Wan,Jang, Seong-Hyung,Yoon, Wang-Jung 대한자원환경지질학회 2007 자원환경지질 Vol.40 No.6

탄성파 속도는 지층 물성에 따라 다양하게 분포한다. 탄성파 음원 모음도 상에 나타나는 이러한 특성은 균질 매질을 고려한 수치 모델링에서는 정상적으로 모사할 수 없으므로 무작위 불균질 매질을 고려한 수치 모델링이 필요하다. 본 연구에서는 불균질 매질 모델을 설정하고, 가우스 자기상관 함수, 지수 자기상관 함수, 폰 카르만 자기상관 함수를 이용하여 단순 지층 구조에 적용하고 각각의 특성을 살펴보았으며, 이 가운데 폰 카르만 자기상관 함수가 단파장 불균질 속도매질을 잘 표현함을 알 수 있었다. 가스 하이드레이트 수치모델링은 동해 현장자료를 바탕으로 해저면과 모델크기를 결정하였으며, 수치모델링 결과 폰 카르만 자기 상관함수가 불균질 지층구조를 포함하는 가스 하이드레이트 속도모델에서 산란현상을 가장 적절하게 구현함을 알 수 있었다. 또한 동해 탄성파 탐사자료의 탄성파 음원 모음도에서 나타나는 해저면 기인 강진폭 위상역전 반사파(BSR: bottom simulated reflector)와 산란파들이 불균질 수치 모형실험에서 적절하게 구현되었음을 알 수 있었다. The seismic velocity at the formation varies widely with physical properties in the layers. These features on seismic shot gathers are not capable of reproducing normally by numerical modeling of homogeneous medium, so that we need that of random inhomogeneous medium instead. In this study, we conducted Gaussian autocorrelation function (ACF), exponential autocorrelation function and von Karman autocorrelation function for getting inhomogeneous velocity model and applied a simple geological model. According to the results, von Karman autocorrelation function showed short wavelength to the inhomogeneous velocity medium. For numerical modeling for a gas hydrate, we determined a geological model based on field data set gathered in the East sea. The numerical modeling results showed that the von Karman autocorrelation function could properly describe scattering phenomena in the gas hydrate velocity model which contains an inhomogeneous layer. Besides, bottom-simulating-reflectors and scattered waves which appear at seismic shot gather of the field data showed properly in the inhomogeneous numerical modeling.

Asymptomatic Tubular Duplication of the Transverse Colon in an Adult

김영완,김준옥,이강영,김남규,조장환 연세대학교의과대학 2005 Yonsei medical journal Vol.46 No.1

Colonic duplication is a rare congenital anomaly of the alimentary tract. In most cases, symptomatic duplications of the colon are recognized and treated by childhood. It is uncommon for these lesions to be detected in the adulthood since they present with vague symptoms if at all. We experienced a case of asymptomatic tubular duplication of the transverse colon in a 40-year-old female. Barium enema revealed a tubular duplication of the transverse colon. The duplicated segment arose from the mid ascending colon and incorporated just proximal to the splenic flexure, running parallel to the transverse colon and communicating with it at both ends. Colonoscopy demonstrated a normal colonic mucosa in the duplicated segment. The diameter of its lumen gradually narrowed proximally and the colonoscope could not be passed through the proximal opening of the segment. The patient did not need any treatment. Duplications of the alimentary tract can be found at any age. The possibility of congenital lesions in the adult population should not be overlooked.

中国特色社会主义视域中的宗教教育与人权保护

김영완 한국종교교육학회 2012 宗敎敎育學硏究 Vol.39 No.-

The explicit clauses concerning religious education are hardly found in the preamble of the Chinese constitutional law. However, the “education” is a concept that includes the “religious education,” and all religious believers and non-believers have the rights and duties of receiving education as Chinese citizens. Thus, it must be right to say that the “religious education” is included in the concept of “education.” Moreover, because the Construction of Socialist Modernization with Chinese Characteristics needs harmonious cooperation between the religious believers and non-believers, one cannot deny the importance of the existence of religious believers. In school education, Chinese students are not forced to believe in or give up any religion. Teachers inculcate students with materialist ideology, but they never force students to negate or abandon religions in China. Under this situation, what kind of ideas on religion do the Chinese students have? The results of several surveys on the Chinese students’ attitude toward religion will be introduced in this paper. Moreover, the limits and the problems of the inculcation of the Marxist faith in accordance with the changing of the times will also be pointed out. The Western idea of human rights was introduced to China through Japan in the 1890s,but it could not take root in the Chinese soil. It is deeply related with the fact that the powers of the West thoroughly violated the human rights of Chinese people. They were the people from so-called the birthplace of human rights! Furthermore, the idea of human rights was stubbornly shunned in China during the Cold War because it was recognized as a Western idea, i.e. the bourgeoisie’s idea originated from the West Camp. As a result, some endogenous factors were generated in China corresponding to these kinds of foreign factors, and the theory of human rights based on the reality of China come into being. Furthermore, the major theoretical changes in human rights have occurred since the reform and opening-up policy which were put into practice from 1978. Human rights have become important parts of socialist value system by being “liberated” from the “bourgeoisie’s ideology.” “The human rights theory with Chinese Characteristics” which is advocated by Chinese government now is of this kind of historical background. Currently, the Chinese constitutional law guarantees human rights as well as freedom of religion. The provisions found in the constitutional laws of the Western camp are now stipulated in the Chinese constitutional law, which was hardly imagined in the past. Freedom of religion and human rights have become legal concepts protected by the state based on the explicit provisions of the Chinese constitutional law, rather than political rights; these rights in China have gained the “signboard” (face) in the world community of nations. Freedom of religion and human rights which are protected by the Chinese constitutional law are expected to be further developed through the organic cooperation with the world society.