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金振謙 한국일본문화학회 1998 日本文化學報 Vol.5 No.-

작은 용적의 전립선비대증 환자에게서 이행대지수의 활용

김진겸,김흥식,설종구 大韓泌尿器科學會 2003 Korean Journal of Urology Vol.44 No.8

작은 용적의 전립선비대증 환자에서 이행대지수의 활용

김진겸,김홍식,설종구 대한비뇨의학회 2003 Investigative and Clinical Urology Vol.44 No.8

IMT-2000 3GPP 시스템을 위한 간단한 다중 전송률 병렬형 간섭제거기

김진겸,오성근,선우명훈,Kim, Jin-Kyeom,Oh, Seong-Keun,Sunwoo, Myung-Hoon 대한전자공학회 2001 電子工學會論文誌-TC (Telecommunications) Vol.38 No.12

본 논문에서는 IMT(international mobile telecommunications)-2000 3GPP(3rd generation partnership project) 규격에 따른 전송률이 서로 다른 다수의 사용자 신호들을 효과적으로 처리할 수 있는 간단한 병렬형 간섭제거기를 제안한다. 제안한 방식은 다중 전송률 처리를 위하여 모든 사용자들에 공통적이며 전송률이 가장 낮은 제어채널의 한 심벌을 기준블록으로 설정하여 기준블록 단위마다 병렬로 간섭제거를 수행한다. 또한, 사용자간 비동기 환경에서 자신보다 짧은 지연을 갖는 간섭 사용자의 다음 기준블록에 의하여 발생하는 간섭을 미리 판정하고 재생하여 제거함으로써 간섭제거 성능을 개선할 수 있는 효과적인 사전 제거 기법을 제안한다. 제안된 사전 제거 기법을 사용한 다중 전송률 처리 병렬형 간섭제거기의 효율적인 구현을 위하여 샘플단위의 파이프라인을 도입하여 기준블록 주기로 판정하고, 이어서 샘플단위로 재생성하고 샘플단위로 간섭제거를 수행함으로써 최소의 하드웨어를 필요로 하는 파이프라인 구조를 제안한다. 모의실험을 통하여 저l안한 간섭제거기의 신호 대 잡음비 및 사용자 수에 따른 비트 오류율 성능을 분석한다. In this paper, we propose an effective but simple multi-rate parallel interference canceller(PIC) for the international mobile telecommunications-2000(IMT-2000) 3rd generation partnership project (3GPP) system. For effective multi-rate processing, we define the basic block as one symbol period of the dedicated physical control channel(DPCCH) having the lowest data rate and common to all users. Then, decision and interference cancellation are performed at every basic block. For an asynchronous channel, we propose an advance removal scheme that removes in advance multiple access interference(MAI) due to the next blockof other users with shorter delay. Introducing a pipeline structure at a sample base, we can implement efficiently the PIC using the advance removal scheme with a minimum hardware and no extra computations. Through computer simulations, we analyze the bit error rate(BER) performance of the proposed PIC with respect to signal-to-noise ratio(SNR) and the number of users.

광학위성을 이용한 수문모형의 보정과 북한 황강댐의 도수량 추정

김진겸 한국수자원학회 2023 물과 미래(한국수자원학회지) Vol.56 No.4

Feasibility of Spin-Echo Echo-Planar Imaging MR Elastography in Livers of Children and Young Adults

김진겸,윤해성,이미정,김명준,한경화,고홍,김승,한석주,신현주 대한자기공명의과학회 2019 Investigative Magnetic Resonance Imaging Vol.23 No.3

Purpose: To assess the feasibility of the use of spin-echo echo-planar imaging (SE-EPI) magnetic resonance elastography (MRE) in livers of children and young adults. Materials and Methods: Patients (≤ 20 years old) who underwent 3T SE-EPI MRE were included retrospectively. Subjects were divided into three groups according to the purpose of the liver MRI: suspicion of fatty liver or focal fat deposition in the liver (FAT group), liver fibrosis after receiving a Kasai operation from biliary atresia (BA group), and hepatic iron deposition after receiving chemotherapy or transfusions (IRON group). Technical failure of MRE was defined when a stiffness map showed no pixel value with a confidence index higher than 95%, and the patients were divided as success and failure groups accordingly. Clinical findings including age, gender, weight, height, and body mass index and magnetic resonance imaging results including proton density fat fraction (PDFF), T2*, and MRE values were assessed. Factors affecting failure of MRE were evaluated and the image quality in wave propagation image and stiffness map was evaluated using the appropriate scores. Results: Among total 240 patients (median 15 years, 211 patients in the FAT, 21 patients in the BA, and 8 patients in the IRON groups), technical failure was noted in six patients in the IRON group (6/8 patients, 75%), while there were no failures noted in the FAT and BA groups. These six patients had T2* values ranging from 0.9 to 3.8 ms. The image quality scores were not significantly different between the FAT and BA groups (P > 0.999), while the scores were significantly lower in the IRON group (P < 0.001). Conclusion: The 3T SE-EPI MRE in children and young adults had a high technical success rate. The technical failure was occurred in children with decreased T2* value (≤ 3.8 ms) from iron deposition.

기계학습을 활용한 열화 재료의 초음파 신호 생성

김진겸,장창희,강성식 한국비파괴검사학회 2023 한국비파괴검사학회지 Vol.43 No.3

This study aims to generate ultrasonic signals of aged nuclear structural materials through machine learning models. Ultrasonic signals were generated using a variational auto-encoder model with a mathematically explainable and reproducible method. Two machine learning models for classification (k-nearest neighbor and multi-layer perceptron) were used to verify the quality of the generated signals. It was confirmed that the generated ultrasonic signals possessed characteristics similar to those of the experimental data, which implies that a large number of new ultrasonic signals can be generated using a small amount of data collected through experiments. 본 연구는 기계학습 모델을 통해 열화된 원자력 구조재료의 초음파 신호를 생성하는 것을 목표로 한다. 변분 오토인코더(variational auto-encoder) 모델을 통해 초음파 신호를 생성하였으며, 수학적으로 설명가능한 방법으로 생성 데이터의 재현성을 확인하였다. 생성된 신호의 품질을 검증하기 위해 두 가지 기계학습분류 모델(k-nearest neighbor 및 multi-layer perceptron)을 사용하였다. 이를 통해 생성된 초음파 신호가 실험데이터와 유사한 특성을 가지고 있음을 확인하였고, 적은 양의 실험 데이터를 활용하여 많은 양의 새로운 초음파 신호를 생성할 수 있음을 확인하였다.

성인 음낭수종 제거술의 10년 결과 보고

김진겸,신주현,임재성 대한비뇨의학회 2008 Investigative and Clinical Urology Vol.49 No.1

Purpose: Although hydrocelectomy is commonly performed in general urological practice, the incidence of complications and the outcomes of this procedure seem to be underreported in the literature. We evaluated the incidence of complications and the outcomes of patients who underwent hydrocelectomy. Materials and Methods: Between January 1996 and December 2005, 289 patients with hydrocele were retrospectively assigned into three groups according to the degree of dissection or the amount of the excision of the hydrocele sac. Group 1 included 78 patients who were treated by dissection and excision of the entire hydrocele sac. Group 2 consisted of 149 patients who were treated by dissection and eversion of the hydrocele sac. The 62 patients in group 3 underwent operations in which there was little or no dissection of the hydrocele. We analyzed the complications, the effects of surgical treatment and the results according to the surgical techniques. Results: The duration of recovery showed no differences among the three groups. The overall complication rate was 36.3%. Transient scrotal swelling occurred in 28.0% of the patients, hematoma in 2.7%, wound infection in 1.7%, and injury to the epididymis or testis, chronic pain and persistent swelling occurred in 1.3%. The overall incidence of postoperative complications was significantly lower among the patients in group 3. The rate of scrotal swelling was significantly correlated to the volume of the hydroceles and the amount of the excision of the hydrocele sac. Conclusions: The long term results of hydrocelectomy were good. The most common complications following scrotal surgery for hydroceles were scrotal swelling, hematoma, wound infection and injury to the epididymis and testis. Most of the complications were treated by conservative management. (Korean J Urol 2008;49:82-87) Purpose: Although hydrocelectomy is commonly performed in general urological practice, the incidence of complications and the outcomes of this procedure seem to be underreported in the literature. We evaluated the incidence of complications and the outcomes of patients who underwent hydrocelectomy. Materials and Methods: Between January 1996 and December 2005, 289 patients with hydrocele were retrospectively assigned into three groups according to the degree of dissection or the amount of the excision of the hydrocele sac. Group 1 included 78 patients who were treated by dissection and excision of the entire hydrocele sac. Group 2 consisted of 149 patients who were treated by dissection and eversion of the hydrocele sac. The 62 patients in group 3 underwent operations in which there was little or no dissection of the hydrocele. We analyzed the complications, the effects of surgical treatment and the results according to the surgical techniques. Results: The duration of recovery showed no differences among the three groups. The overall complication rate was 36.3%. Transient scrotal swelling occurred in 28.0% of the patients, hematoma in 2.7%, wound infection in 1.7%, and injury to the epididymis or testis, chronic pain and persistent swelling occurred in 1.3%. The overall incidence of postoperative complications was significantly lower among the patients in group 3. The rate of scrotal swelling was significantly correlated to the volume of the hydroceles and the amount of the excision of the hydrocele sac. Conclusions: The long term results of hydrocelectomy were good. The most common complications following scrotal surgery for hydroceles were scrotal swelling, hematoma, wound infection and injury to the epididymis and testis. Most of the complications were treated by conservative management. (Korean J Urol 2008;49:82-87)

과도 검출 기반의 적응적 오디오 워터마킹

김진겸,박병서,서영호,김동욱 한국정보통신학회 2023 한국정보통신학회논문지 Vol.27 No.2

Beacon을 이용한 실내 재실 여부 결정 및 실내 측위 기술을 통해 다양한 실내 위치기반 서비스를 제공할 수 있다. 하지만, Beacon이 송출하는 BLE 신호는 다중 경로 페이딩 등의 문제로 인해 RSSI 값이 불안정하기 때문에 재실 여부 결정의 정확도를 보장하기 어렵다. 본 논문에서는 다양한 상황에서도 정확성을 보장하기 위해 강의실의 문이 열린 상태에서 데이터를 수집하였다. 수집된 데이터를 기반으로 신호의 특성을 고려한 재실 여부 결정 방법을 제안한다. 제안된 방법은 SVM 모델을 사용하며, 수신 신호 강도만을 사용한 결과에 비해 약 10% 정확도 향상을 보였다. 이 방법은 수신기 하나만으로도 재실 여부를 정확하게 판단할 수 있다는 장점이 있다. 제안된 방법을 통해 정확도 높은 염가형 재실 여부 결정 시스템을 구현할 수 있을 것으로 기대된다.

지형학적 인자에 따라 군집화된 중소규모유역의 합성단위도법 제시

김진겸,김종민,강부식 대한토목학회 2016 대한토목학회논문집 Vol.36 No.3

The methodology of synthetic unit hydrograph using geomorphic characteristics was suggested. Six geomorphic components over 19 watersheds were used to estimate synthetic unit hydrograph and the test watersheds were classified into two groups on the basis of the area of 200km 2 . The regression formulas between standardized geomorphic characteristics for each group and peak quantities of specific streamflow and time of representative unit hydrograph were suggested and the Nash and the Clark unit hydrographs were derived. For verifying the derived unit hydrographs, the resulting hydrographs were compared with the ones using the existing Clark unit hydrographs based on the empirical parameter estimation for the 145 storm events during 2010 to 2011 for the additional six watersheds. The results showed the relatively higher performance over the existing synthetic unit hydrograph methods, which could be a contribution to the hydrologic estimation in ungauged watersheds. 유역의 지형학적특성을 이용한 합성단위도법을 제시하였다. 합성단위도 산정을 위하여 19개 유역에 대하여 6개 지형학적 인자를 사용하였으며, 전체유역을 유역면적 200km 2을 기준으로 2개의 군집으로 분류하였다. 19개 유역을 대상으로 군집별로 표준화된 지형학적 인자와 유역별 대표단위도의 첨두비유량 및 첨두시간과의 회귀식을 제시하였으며, Nash와 Clark 단위도를 유도하였다. 합성단위도의 모의정확도 검증을 위해 추가적으로 선택한 6개 유역에서 2010-2011년에 발생한 145개 강우-유출사상에 적용하여 경험식을 사용한 Clark모형의 적용결과와 비교하였다. 검증결과 기존의 합성단위도법에 비해 높은 정확도를 나타내었으며, 이러한 결과는 미계측 유역에서의 적용 가능성을 보여주었다.