송수신기가 고정된 천해 수중음향통신 채널 매개변수 해석

배민자,박지현,윤종락,Bae, Minja,Park, Jihyun,Yoon, Jong Rak 한국음향학회 2019 韓國音響學會誌 Vol.38 No.5

수중음향통신시스템의 모뎀이나 채널 코딩 설계를 위한 채널 매개변수는 임펄스 응답, 지연 확산, 산란함수, 도플러 확산, 상관 대역폭, 주파수 선택적 페이딩, 상관 시간 및 시변 진폭 페이딩의 통계적 분포 함수 등이다. 이들 매개 변수들은 주어진 해양 음향 조건에서 수층의 음속 구조, 플렛폼의 운동이나 해면의 거칠기에 영향을 받는다. 본 논문에서는 송수신기 고정 천해 수중음향통신 채널에 대한 페이저 기반의 채널 모델과 모의실험 및 채널 매개변수들의 측정과 분석 방법을 제시하고 천해의 실험 자료를 이용하여 이들 매개변수들을 해석하였다. 송수신기 거리가 300 m와 600 m에 대한 이들 매개 변수들은 직접파, 산란 성분을 갖는 해면 반사파 및 해저 반사파로 구성되는 3개 다중 경로에 의해 그 특징이 결정됨을 보인다. 연구의 결과는 천해 고정 시스템의 채널 모델 방법, 채널 매개변수들의 측정과 분석 방법 및 시스템 설계와 성능평가 방법을 제시한다. Underwater acoustic communication channel parameters consist of impulse response, delay spreading, scattering function, coherence bandwidth, frequency selective fading, coherence time and time variant magnitude fading statistics on which communication system modem and channel coding are designed. These parameters are influenced by sound velocity profile, platform motion and sea surface roughness in given acoustical oceanography condition. In this paper, channel model based on phasor, channel simulator, measurement and analysis method of channel parameters are given in a fixed source-to-receiver system and the parameters are analyzed using shallow water experimental data. For two different source-to-receiver ranges of 300 m and 600 m, the parameters are characterized by three multipaths such as a direct, a surface reflection path with time variant scattering and a bottom reflection path. The results present a channel modelling method of a fixed source source-to-receiver system, channel parameters measurement and analysis methods and a system design and performance assessment method in shallow water.

Multipath Fading Channel Characterization and Performances of Forward Error Correction Codes in Very Shallow Water

배민자,설단단,박지현,윤종락,Bae, Minja,Xue, Dandan,Park, Jihyun,Yoon, Jong Rak The Korea Institute of Information and Commucation 2015 한국정보통신학회논문지 Vol.19 No.10

극 천해 음향 통신 채널에서 수중 음향 통신 신호는 시변 다중 경로에 의해 주파수 선택적인 페이딩 신호로 관측된다. 이러한 특성으로 시간 및 주파수에 따라 심벌간의 간섭이 변화하고 수중 통신 시스템의 성능이 저하된다. 오류 정정 코드의 성능이 어떻게 극 천해 다중경로 페이딩의 통계적 특성과 관계되는지에 대한 연구는 전무하다. 본 연구에서는 다중경로 채널의 특성을 해석하고 2가지 전방 오류 정정 코드를 적용하여 극 천해 다중 경로 채널에서 이들의 성능을 비교하였다. 컨벌류션 코드와 Reed-Solomon 코드를 적용한 해상 실험 결과는 Reed-Solomon 코드가 주파수 선택적인 페이딩 채널에서 컨벌류션 코드 보다 우수함을 보였다. In very shallow water acoustic communication channel, underwater acoustic (UWA) communication signal is observed as frequency selective fading signal due to time-varying multipath. This induces a time and frequency dependent inter-symbol-interference (ISI) and degrades the UWA system performance. There is no study about how the performances of the error correction codes are related to a multipath fading statistics in very shallow water. In this study, the characteristics of very shallow water multipath fading channel is analyzed and the performances of two different forward error correction (FEC) codes are compared. The convolution code (CC) and Reed-Solomon (RS) code are adopted. Sea experimental results show that RS code is better choice than CC in frequency selective channel with fading.

부산해역 수중음향통신채널의 통계적 분석과 통신성능 해석

배민자(Minja Bae),박지현(Jihyun Park),김종주(Jongju Kim),윤종락(Jong Rak Yoon) 한국소음진동공학회 2017 한국소음진동공학회 학술대회논문집 Vol.2017 No.4

結核性心囊炎의 1例 報告

裵敏子,韓禮澤,金舜英,金相協 金原出版 1974 小兒科 Vol.15 No.6

就業婦人과 非就業婦人의 夫婦適應에 關한 比較硏究

裵敏子 단국대학교 대학원 1981 學術論叢 Vol.5 No.-

Ⅰ. Ten purpose and contents of the research This research aims to give us the basic data to further the mutural understanding of the wife and husband and their family members through the analyris of the difference on the merital adjustment of the families between professional women and non­professional women in terms of task role as well as their socioemotional role. The major area of concerns are as follows : 1. The role structure of husband­wife. a. Domestic activities. b. Economic activities. c. Outside activities. d. The rearing and education of children. 2. The socio­emotional adjustment of husband­wife. a. The dicision making right of husband­wife. b. The dialogue of husband­wife. c. Leisure activities at home and outside home. d. The mutural affection and sexual relationship. e. The liquor drinking of husband. Ⅱ. The method of research This research is based on the responses of the questionaires on the marital adjustment to the housewives who live in Seoul. The questionaires were distibuted to professional women (203) consisting of women teachers (168) serving in the elementary schools and other profe­ssional women (35). Non­professional women are 198 housewives who have no jobs at all. The inquiring was performed from Sep. 17, 1980 to Sep. 20, 1980. The data was basically analyzed by using percent and a divisor and was computerized in the computer room of Dan­Kuk University. Ⅲ. Findings. A. The role structure of the spouse. It was found that the wife plays the dominant role still in the four fields such as domestic activities, economic activities, outside activities, and the rearing and education of children. The participation in role shows higher in the families of non­professional women than in those of professional women. that is, families of professional women are correlatively complementary and highly participative in their mutural activities as far as their envirnments allow them to do. On examing the type of family, it is found that the nuclear family enjoy more active mutual participation than extended family having more leisure time. More coopereation of husband is given to the families of professional women and to the unclear families to the extended families. Therefore, the effort of husband including family members should be encouraged in sharing several family affairs of professional women. B. Socio­amotional adjustment. 1. The dicision of the wife and husband is made mutually agreed by 74%. However, this is differed whether the wife has job or not. The purchase of the house is dicided more cooperatively in the families of professional women than in those of nonprofessional women. therefore it is found that professional women is more powerful in the dicision making in the family than non­professional women. 2. In general, the degree of identification in dialogue of husband and wife is made without any conflict and is made more highly in made more highly in the families of professional women than in those of non­professional women by 73.9% to 67.2%. The contents of the dialogue shows the differences in that professional women enjoy the talks about love, sex, and leisure activities and non­professional women enjoy the talks about their daily living and relatives. 3. In spending their leisure time of husband and wife, professional women take more active part in their planning of vacation compared to non­professional women by 71.9% to 59.6%. professional women go outside home with husband more often than non­professional women by 32.0% to 18.3%. That is, professional women were in thythm and keep more joyful relationship with their husbands and think their role more important than the others. 4. Regarding the affection and sexual relationship of the wife anh husband, professional women express their love to more strongly to their husband than non­professional women by 36.9% to 18.3%. On the special occasion (the memorial date of marriage, the birthday of wife, and when ill), the special loving is given to professional women by 71.9% to 67.9%. The affection and love between husband and wife is positive in families of professional women, who are taken care of specially than non­professional women. The talk about sexual life is more often made by professional women than non­professional women by 74.9% to 60.6%. The frequency of having sex is more often to professional women. However, the reason of finishing dissatisfied sexual life to the professional women is mainly due to the bodily fatigue by 44.8% to 29.8% to non­professional women. Regarding the degree of satisfaction in sexual life, professional women are more satisfied than non­professional women by 41.9% to 37.9%. 5. Referring to the drinking of husband, husband of professional women tends to like drinking more than those of non­professional women and the effect of husband's drinking is that husbands of professional women come back home late by the ration of 57.6% to 49.0%. In the final analysis of the above research, it is found that the employment of wives changes to have more democratic trend affirmatively to the internal relationship of husband and wife viewing on the socio­emotional adjustment to the society. Further­more, families of professional women keep more satisfied interrelationship of husband and wife than those of non­professional women to the degree of the concurrence of dicision­making and opinion in dialogue, and the happiness of marriage life.

遺傳性 球狀赤白血球症 : 三例 報告 A Report of 3 Cases

裵敏子,皮守英,申相滿,洪彰義 金原出版 1974 小兒科 Vol.15 No.6

시·공간 변동 수중음향 채널에서 CAZAC 코드를 적용한 반송파 주파수 옵셋 보상 기법의 성능평가

박지현,배민자,김종주,윤종락,Park, Jihyun,Bae, Minja,Kim, Jongju,Yoon, Jong Rak 한국정보통신학회 2016 한국정보통신학회논문지 Vol.20 No.7

수중 음향 다중경로 채널에서 수중음향 통신 시스템의 성능은 채널의 시변적 경계면 상태 변동에 의해 영향을 받는다. 이러한 채널에서 시공간적 변동에 의해 송신 신호와 수신 신호의 위상과 주파수가 일치하지 않아 반송 주파수 옵셋이 발생되고 위상편이키잉 방식의 수중음향통신시스템의 성능을 저하시킨다. 본 논문에서는 수중 음향 통신 채널의 시 공간적 변동 채널에서 위상 코드를 적용한 반송 주파수 옵셋 보상 추정 기법의 성능을 평가하였다. 위상 코드는 주파수 옵셋을 추정하고 보상하기 위한 코드로 CAZAC를 적용하였으며, 실내 수조에서 성능을 평가하였다. QPSK 시스템에 위상코드를 적용한 결과는 적용하지 않은 경우보다 약 4-6배 비트오류율이 개선되었다. In underwater acoustic multipath channel, a performance of underwater acoustic (UWA) communication systems is affected by dynamic variation of boundary and high temporal and spatial variability of the channel conditions. Time and spatial variations of UWA channel induce a carrier frequency offset (CFO) since a phase and a frequency of received signal mismatch with a transmitting signal. Therefore, a performance of a phase shift keying underwater acoustic communication system is degraded. In this study, we have analyzed a performance of CFO estimation and compensation using a phase code in time and spatial variation channel. A constant amplitude zero autocorrelation (CAZAC) signal is applied as a phase code signal and its performance is evaluated in water tank. The bit error rate of a quadrature phase shift keying (QPSK) system with a phase code is improved about 4 to 10 times better than that without a phase code.

차량소음의 등가소음높이 측정을 위한 마이크로폰 배열 설계

윤종락,배민자 한국소음진동공학회 1995 소음 진동 Vol.5 No.2

Microphone array is designed to measure the equivalent source height of vehicle noise. The equivalent source position is defined for an arbirary distribution of acoustic sources above a perfectly reflecting plane and a microphone array for its measurement is developed. The normalized errors of the measured equivalent source heights are defined including the effects of background noise, the geometric near field, and source size. Normalized errors of the measured source heights obtained by a nemerical simulation for each parameter lead to optimization of the microphone spacing and to the design of an array which gives the equivalent source height as a function of frequency. The performance of the designed array is verified using the stationary loudspeaker experiments.

小兒의 白血病腦膜症狀(Meningeal Leukemia)의 臨床的 觀察 : A Review of 11 Cases

金相祐,裵敏子,申愛羅,張永吉,洪彰義 金原出版 1974 小兒科 Vol.15 No.6

Effect of frequency dependent multipath fading on non-coherent underwater communication system

김종주,박지현,배민자,박규칠,윤종락,Kim, Jongjoo,Park, Jihyun,Bae, Minja,Park, Kyu-Chil,Yoon, Jong Rak The Acoustical Society of Korea 2016 韓國音響學會誌 Vol.35 No.4

수중음향 채널은 다양한 경로들이 상호 간섭하여 주파수에 따른 보강 또는 상쇄 간섭을 보이는 다중경로 페이딩 채널로 정의된다. 따라서 수신신호의 신호 대 잡음비는 주파수에 따라 변화한다. 아울러 해면변동은 해면 반사경로의 코히어런트 성분의 주파수에 따른 시변 페이딩을 야기한다. 주파수 편이 키잉 시스템은 이러한 간섭과 페이딩에 덜 민감하여 강인한 시스템으로 알려져 있으며 전송률을 높이기 위해 다진 주파수 편이 키잉 시스템으로 사용되고 있다. 본 연구에서는 4 채널 4진 주파수 편이 키잉 시스템의 비트오류율을 천해 다중경로 채널에서 실험하였다. 실험결과 주파수 종속 시변 수중 음향 다중경로 페이딩은 연집오류를 발생시키는 특성을 보여 리드 솔로몬 코드가 4진 주파수 편이 키잉 시스템의 비트오류율을 효과적으로 경감시키는지를 보였다. 따라서 데이터 전송율 혹은 송수신기 거리에 따른 비트 오류율은 채널의 대역폭뿐만 아니라 주파수 종속 다중 경로 페이딩에 좌우됨을 보인다. Underwater acoustic communication channel is often defined as a multipath fading channel since the multipath arrivals from various paths interfere with each other and cause frequency dependent constructive or destructive interference in received signals. Therefore signal-to-noise ratio (SNR) of received signal fluctuates as a function of frequency. In addition, sea surface fluctuation induces frequency dependent time variant signal fading due to coherent component variation of surface bounce path. The frequency shift keying (FSK) system is known to be less sensitive and more robust under these interference and fading, and M-ary frequency shift keying (MFSK) system is adopted to increase a data rate. In this study, a bit error rate (BER) of 4 channels 4FSK system are examined in shallow sea multipath channel. Experimental results show that RS code reduces efficiently the BER of 4FSK system since frequency dependent time-varying fading is characterized to give burst errors. The BER of a different data rate or different source-to-receiver range depends on not only the channel coherent bandwidth but also frequency dependent multipath fading.