A Rare Case of Cystic Subepithelial Tumor in the Stomach: Gastric Adenomyoma

이호석,장윤진,허준 대한영상의학회 2015 대한영상의학회지 Vol.73 No.6

Gastric adenomyoma is a rare benign subepithelial tumor, characteristically composed of mucosal structures and a prominent smooth muscle stroma. Because of rarity and the nonspecific computed tomography (CT) features, it is difficult to diagnose gastric adenomyoma before operation. In our case, gastric adenomyoma showed a well-circumscribed cystic subepithelial mass with uneven wall thickness on a CT scan, similar to the findings of former reports. The radiologic differential diagnosis can be narrowed down to several diseases, including duplication cysts, gastritis cystica profunda, brunner’s gland hyperplasia and solid tumors with cystic degeneration. Also, adenomyoma could be included in the differential diagnosis of gastric cystic subepithelial masses, especially in the distal part of the stomach.

CONSUMPTION-LEISURE CHOICE WITH STOCHASTIC INCOME FLOW

이호석,임병화 충청수학회 2020 충청수학회지 Vol.33 No.1

This paper investigates the portfolio selection problem with flexible labor choice and stochastic income flow where the unit wage flow is governed by a stochastic process. The agent optimally chooses consumption, investment, and labor supply. We derive the closed-form solution by applying a martingale method even with the stochastic income flow.

Video object segmentation using a novel object boundary linking

이호석,Lee Ho-Suk Korea Information Processing Society 2006 정보처리학회논문지B Vol.13 No.3

비디오에서 움직이는 객체의 외곽선은 객체를 정확하게 분할하기 위하여 매우 중요하다. 그러나 움직이는 객체의 외곽선에는 단락된 외곽선들이 존재하게 된다. 우리는 단락된 외곽선을 연결할 수 있는 새로운 외곽선 연결 알고리즘을 개발하였다. 외곽선 연결 알고리즘은 단락된 외곽선의 말단 픽셀에 사분면을 형성하고 동심원을 구성하면서 반지름 내에서 다른 말단 픽셀을 찾는 탐색을 전진하면서 수행한다. 외곽선 연결 알고리즘은 객체의 외곽선에서 가장 짧게 외곽선을 연결한다. 그리고 시스템은 비디오로부터 배경을 구하여 저장한다. 시스템은 외곽선 연결로부터 객체 마스크를 생성하고, 배경된 저장으로부터 또 하나의 객체 마스크를 생성하여 이 두 개의 객체 마스크를 보완적으로 사용하여 움직이는 객체를 분할한다. 논문의 주요 장점은 정확한 객체 분할을 위한 새로운 객체 외곽선 연결 알고리즘의 개발이다. 제안된 알고리즘은 개발된 새로운 객체 외곽선 연결 알고리즘과 배경 저장을 이용하여 정확한 객체 분할, 다중 객체 분할, 내부에 구멍이 존재하는 객체의 분할, 가느다란 객체의 분할, 그리고 복잡한 배경을 가진 객체를 자동으로 분할하여 보여주었다. 우리는 알고리즘들을 표준 MPEG-4 실험 영상과 카메라로 입력된 실제 영상을 가지고 실험하였다. 제안된 알고리즘들은 매우 효율이 좋으며 펜티엄-IV 3.4GHz CPU에서 평균적으로 QCIF 영상을 1초당 70.20 프레임 그리고 CIF 영상을 1초당 19.7 프레임을 실시간 객체 응용을 위하여 처리할 수 있다. Moving object boundary is very important for the accurate segmentation of moving object. We extract the moving object boundary from the moving object edge. But the object boundary shows broken boundaries so we develop a novel boundary linking algorithm to link the broken boundaries. The boundary linking algorithm forms a quadrant around the terminating pixel in the broken boundaries and searches for other terminating pixels to link in concentric circles clockwise within a search radius in the forward direction. The boundary linking algorithm guarantees the shortest distance linking. We register the background from the image sequence using the stationary background filtering. We construct two object masks, one object mask from the boundary linking and the other object mask from the initial moving object, and use these two complementary object masks to segment the moving objects. The main contribution of the proposed algorithms is the development of the novel object boundary linking algorithm for the accurate segmentation. We achieve the accurate segmentation of moving object, the segmentation of multiple moving objects, the segmentation of the object which has a hole within the object, the segmentation of thin objects, and the segmentation of moving objects in the complex background using the novel object boundary linking and the background automatically. We experiment the algorithms using standard MPEG-4 test video sequences and real video sequences of indoor and outdoor environments. The proposed algorithms are efficient and can process 70.20 QCIF frames per second and 19.7 CIF frames per second on the average on a Pentium-IV 3.4GHz personal computer for real-time object-based processing.

폐합병증을 동반한 심한 면역저하 환자에서 폐생검술의 유효성 및 위험성에 대한 분석

이호석,이성호,김관민,심영목,한정호 대한흉부심장혈관외과학회 2001 Journal of Chest Surgery (J Chest Surg) Vol.34 No.7

배경: 면역저하 환자에게 발생하는 폐 합병증은 흔히 치명적이다. 폐생검술과 같은 침습적인 진단 술기의 위험도 때문에 일반적으로 임상 양상과 방사선 영상 소견에 근거하여 경험적인 치료가 적용된다. 그러나 최근 수술 술기와 수술 전후의 환자 관리의 발전으로 인해 술기와 연관된 위험도는 줄어든 실정이다. 이에 폐합병증을 동반한 심한 면역저하 환자에서 시행된 폐생검술의 위험성 및 유효성에 대하여 전향적으로 분석하였다. 대상 및 방법: 1996년 6월부터 1999년 12월까지 폐합병증을 동반한 면역저하 환자 42명에서 43례의 폐생검술을 실시하였다. 면역저하는 다음과 같이 정의하였고(1, 혈액학적인 질환으로 인해 화학요법이나 다른 치료를 동반하여 받은 경우, 2. 이식 수술 후 면역 억제제를 복용하는 경우, 3. 1 개월 이상의 스테로이드 복용, 4. 원발성 면역결핍 질환), 이상의 면역저하 환자에서 새로운 폐합병증을 동반하고 1 주간의 경험적 치료에 호전이 없거나 급속하게 진행되는 경우를 대상으로 하였다 기저 질환은 혈액학적 질환(31명), 이식 수술 환자(3명), 고형암으로 인한 화학요법(2명)등이었으며 수술은 개흉술이나 video-aided thoracoscopic surgery (VATS)를 통하여 이루어 졌다. Background: Pulmonary complications in immunocompromised patients are often fatal. Empirical treatment is usually applied based on the clinical and radiological findings because of the risk of the aggressive diagnostic procedures such as open lung biopsy. However, recent advancements in operative procedures and perioperative management has decreased the procedure-related risks. We have prospectively analyzed the risks and benefits of the early application of open lung biopsy in such patients. Material and Method: Forty-two consecutive immunocompromised patients with critical pulmonary complications were included from June, 1996 to December, 1999. The definition of the immunocompromised is as those with chemotherapy and/or other modality for hematologic disorders, with usage of immunosuppressive drug after transplantation, with usage of steroid for more than 1 month, and with primary immunodeficiency disorders. The indication of open lung biopsy was those with no significant improvement after a week of aggressive application of empirical treatment or with rapidly aggressive process. The underlying disease included hematologic disorder(31 patients), post-transplantation(3 patients), chemotherapy for solid tumor(2 patients), and others(6 patients). Operations were done through thoracotomy(conventional or mini-) or VATS.

고속열차의 터널 진입시 발생하는 압력변화에 대한 수치 해석적 연구

이호석,김동현 한국도시철도학회 2018 한국도시철도학회논문집 Vol.6 No.4

Sudden pressure changes caused by the high-speed train entering the entrance of the tunnel are propagated into the tunnel and spread out around the tunnel in the form of a micro pressure wave at the exit of the tunnel. This phenomenon can cause noise and vibration around the tunnel, causing damage to the surroundings. Analysis of this phenomenon is very difficult, but the development of analytical technology has revealed more phenomena than in the past. In this study, we propose this method of analysis and compare it with the experimental data to show the data with higher reliability.

[조명] 방열기술/수중 누설전류 제한기술 등 다수의 기술인증 LED 조명업체 (주)비젼테크

이호석 한국조명·전기설비학회 2019 조명.전기설비 Vol.33 No.1

Evaluation of the Subscapularis Tendon Tears on 3T Magnetic Resonance Arthrography: Comparison of Diagnostic Performance of T1-Weighted Spectral Presaturation with Inversion-Recovery and T2-Weighted Turbo Spin-Echo Sequences

이호석,안중모,강유선,Joo Han Oh,Eugene Lee,이준우,강흥식 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2

Objective: To compare the T1-weighted spectral presaturation with inversion-recovery sequences (T1 SPIR) with T2-weighted turbo spin-echo sequences (T2 TSE) on 3T magnetic resonance arthrography (MRA) in the evaluation of the subscapularis (SSC) tendon tear with arthroscopic findings as the reference standard. Materials and Methods: This retrospective study included 120 consecutive patients who had undergone MRA within 3 months between April and December 2015. Two musculoskeletal radiologists blinded to the arthroscopic results evaluated T1 SPIR and T2 TSE images in separate sessions for the integrity of the SSC tendon, examining normal/articular-surface partial-thickness tear (PTTa)/full-thickness tear (FTT). Diagnostic performance of T1 SPIR and T2 TSE was calculated with arthroscopic results as the reference standard, and sensitivity, specificity, and accuracy were compared using the McNemar test. Interobserver agreement was measured with kappa (κ) statistics. Results: There were 74 SSC tendon tears (36 PTTa and 38 FTT) confirmed by arthroscopy. Significant differences were found in the sensitivity and accuracy between T1 SPIR and T2 TSE using the McNemar test, with respective rates of 95.9−94.6% vs. 71.6−75.7% and 90.8−91.7% vs. 79.2−83.3% for detecting tear; 55.3% vs. 31.6−34.2% and 85.8% vs. 78.3−79.2%, respectively, for FTT; and 91.7−97.2% vs. 58.3−61.1% and 89% vs. 78−79.3%, respectively, for PTTa. Interobserver agreement for T1 SPIR was almost perfect for T1 SPIR (κ = 0.839) and substantial for T2 TSE (κ = 0.769). Conclusion: T1-weighted spectral presaturation with inversion-recovery sequences is more sensitive and accurate compared to T2 TSE in detecting SSC tendon tear on 3T MRA.

폐자동차 자원순환체계 선진화 시범사업에 따른 경제적, 환경적 효과 및 향후 제도 개선 방향

이호석 한국폐기물자원순환학회(구 한국폐기물학회) 2017 한국폐기물자원순환학회 심포지움 Vol.2017 No.1

새로운 객체 외곽선 연결 방법을 사용한 비디오 객체 분할

이호석 한국정보처리학회 2006 정보처리학회논문지. 소프트웨어 및 데이터 공학 Vol.13 No.3

비디오에서 움직이는 객체의 외곽선은 객체를 정확하게 분할하기 위하여 매우 중요하다. 그러나 움직이는 객체의 외곽선에는 단락된 외곽선들이 존재하게 된다. 우리는 단락된 외곽선을 연결할 수 있는 새로운 외곽선 연결 알고리즘을 개발하였다. 외곽선 연결 알고리즘은 단락된 외곽선의 말단 픽셀에 사분면을 형성하고 동심원을 구성하면서 반지름 내에서 다른 말단 픽셀을 찾는 탐색을 전진하면서 수행한다. 외곽선 연결 알고리즘은 객체의 외곽선에서 가장 짧게 외곽선을 연결한다. 그리고 시스템은 비디오로부터 배경을 구하여 저장한다. 시스템은 외곽선 연결로부터 객체 마스크를 생성하고, 배경된 저장으로부터 또 하나의 객체 마스크를 생성하여 이 두 개의 객체 마스크를 보완적으로 사용하여 움직이는 객체를 분할한다. 논문의 주요 장점은 정확한 객체 분할을 위한 새로운 객체 외곽선 연결 알고리즘의 개발이다. 제안된 알고리즘은 개발된 새로운 객체 외곽선 연결 알고리즘과 배경 저장을 이용하여 정확한 객체 분할, 다중 객체 분할, 내부에 구멍이 존재하는 객체의 분할, 가느다란 객체의 분할, 그리고 복잡한 배경을 가진 객체를 자동으로 분할하여 보여주었다. 우리는 알고리즘들을 표준 MPEG-4 실험 영상과 카메라로 입력된 실제 영상을 가지고 실험하였다. 제안된 알고리즘들은 매우 효율이 좋으며 펜티엄-IV 3.4GHz CPU에서 평균적으로 QCIF 영상을 1초당 70.20 프레임 그리고 CIF 영상을 1초당 19.7 프레임을 실시간 객체 응용을 위하여 처리할 수 있다. Moving object boundary is very important for the accurate segmentation of moving object. We extract the moving object boundary from the moving object edge. But the object boundary shows broken boundaries so we develop a novel boundary linking algorithm to link the broken boundaries. The boundary linking algorithm forms a quadrant around the terminating pixel in the broken boundaries and searches for other terminating pixels to link in concentric circles clockwise within a search radius in the forward direction. The boundary linking algorithm guarantees the shortest distance linking. We register the background from the image sequence using the stationary background filtering. We construct two object masks, one object mask from the boundary linking and the other object mask from the initial moving object, and use these two complementary object masks to segment the moving objects. The main contribution of the proposed algorithms is the development of the novel object boundary linking algorithm for the accurate segmentation. We achieve the accurate segmentation of moving object, the segmentation of multiple moving objects, the segmentation of the object which has a hole within the object, the segmentation of thin objects, and the segmentation of moving objects in the complex background using the novel object boundary linking and the background automatically. We experiment the algorithms using standard MPEG-4 test video sequences and real video sequences of indoor and outdoor environments. The proposed algorithms are efficient and can process 70.20 QCIF frames per second and 19.7 CIF frames per second on the average on a Pentium-IV 3.4GHz personal computer for real-time object-based processing.

직장암의 복강경직장절제술 후 발생되는 문합부누출의 위험요소: 복강경직장절제술은 문합부누출을 높이는가?

이호석,김민권,박창균,조유진,황덕원,노상익 대한대장항문학회 2007 Annals of Coloproctolgy Vol.23 No.2

Purpose: The purpose of this study is to evaluate the risk factors for clinical anastomotic leakage after laparoscopic resection for rectal cancer. Methods: From March 2001 and February 2006 in Seoul Veterans’ Hospital, the prospective laparoscopic colorectal resection database identified 101 patients who a had laparoscopic rectal resection with colorectal or coloanal anastomosis. The associations between clinical anastomotic leakage and patient-, tumor-, surgery- and laparoscopic-related variables were studied. Results: The rate of clinical anastomotic leakage was 4 percent (4 of 101). The patient-related variable significantly associated with clinical anastomotic leakage was preoperative radiotherapy. The surgery-related factor that turned out to be significant was anastomosis situated less than 5 cm from the anal verge. No tumor- or laparoscopic-related variables were significantly associated with clinical anastomotic leakage. Conclusions: A protective ileostomy should be considered after a laparoscopic rectal resection for an rectal cancer for anastomosis situated less than 5 cm from the anal verge, particularly when preoperative radiotherapy is being used.