인접전류패턴을 사용한 변형된 방향 대수적 영상복원법

김지훈,김찬용,김경연,최봉열,Kim, Ji Hoon,Kim, Chan Yong,Kim, Kyung Youn,Choi, Bong Yeol 대한전자공학회 2012 전자공학회논문지 Vol.50 No.8

전기 임피던스 단층촬영법(electrical impedance tomography, EIT)에서 관심 대상물 내부 영상을 복원하는 방법 중 하나인 방향 대수적 영상복원법(directional algebraic reconstruction technique, DART)은 삼각함수형태로 설계된 전류패턴을 외부 전극에 인가하고 이로부터 얻어지는 전압과의 상관관계를 이용하여 영상복원 알고리즘의 입력인 각 전극사이의 저항을 유도하게 된다. 이때, 저항유도 시간이 발생하고 이는 DART 알고리즘을 실시간 영상복원에 적용하는데 장애가 되고 있다. 이 논문에서는 저항유도 시간의 문제를 해결하기 위하여 기존에 사용하던 삼각함수형태의 전류패턴대신 인접전류패턴을 사용한 변형된 방향 대수적 영상복원법(modified directional algebraic reconstruction technique, mDART)을 제안한다. 제안한 방법은 주입한 전류와 측정된 전압으로부터 저항을 유도하지 않고 측정전압을 바로 복원 알고리즘의 입력으로 사용하기 때문에 DART의 영상복원시간의 대부분을 차지하는 저항유도 시간을 없앨 수 있을 뿐만 아니라 인접전류패턴을 사용하여 복원영상의 질도 향상시킬 수 있다. 이 논문의 타당성을 입증하기 위하여 모의실험을 수행하였으며 제안한 방법은 기존 방법보다 복원시간의 개선뿐만 아니라 영상오차 관점에서도 성능이 개선됨을 확인하였다. The directional algebraic reconstruction technique (DART) using the trigonometric current pattern is one of the image reconstruction algorithms in electrical impedance tomography (EIT). This method needs to compute resistances between electrode pairs as using relation between the injected currents and measured voltages for the reconstruction of the inner image. The delay time is incurred in this process. Therefore this paper proposes modified directional algebraic reconstruction technique (mDART) using the adjacent current pattern instead of the trigonometric current pattern to solve the delay time for initial resistance values. The proposed method uses measured voltages instead of computed resistances in the reconstruction algorithm. Hence this method can eliminate the delay time because it does not use the resistances. In conclusion, the proposed method improves image quality and image reconstruction time by using the adjacent current pattern. To prove performance of the proposed method, we carried on computer simulation of various cases.

소아 궤양성 대장염의 수술적 치료 성적

김지훈,김현영,정성은,박귀원,김우기,Kim, Ji-Hoon,Kim, Hyun-Young,Jung, Sung-Eun,Park, Kwi-Won,Kim, Woo-Ki 대한소아외과학회 2005 소아외과 Vol.11 No.2

Ulcerative colitis, an inflammatory bowel disease, is primarily managed medically with a combination of 5-ASA and steroids. However, this chronic disease requires surgical management if symptoms persist or complications develop despite medical management. The clinical course, indications and outcome of surgical management of 21 patients under the age of 15 who were endoscopically diagnosed with ulcerative colitis at the Seoul National University Children's Hospital between January, 1988 and January, 2003 were reviewed. Mean follow up period was 3 years and 10 months. The mean age was 10.3 years old. All patients received medical management after diagnosis and 8 patients (38 %) eventually required surgical management. Of 13 patients who received medical management only, 7 patients (53 %) showed remission, 4 patients are still on medical management, and 2 patients expired due to congenital immune deficiency and hepatic failure as a result of sclerosing cholangitis. In 8 patients who received surgical management, the indications for operation were, 1 patient sigmoid colon perforation and 7 patients intractability despite medical management. The perforated case had a segmental colon resection and the other 7 patients underwent total colectomy with ileal pouch-anal anastomosis. One patient expired postoperatively due to pneumonia and sepsis. and 1 is still on medical management because of mild persistent hematochezia after surgery. Six other operated patients are doing well without medical therapy. Pediatric ulcerative colitis patients can be surgically managed if the patient is intractable to medical management or if complications such as perforation are present. Total colectomy & ileal pouch-anal anastomosis is thought to be the adequate surgical method.

근위부 위절제술 후 재건 술식에 따른 경과 관찰

김지훈,육정환,김병식,오성태,Kim, Ji-Hoon,Yook, Jeong-Hwan,Kim, Byung-Sik,Oh, Sung-Tae 대한위암학회 2006 대한위암학회지 Vol.6 No.1

Purpose: A proximal gastrectomy is performed for gastric cancer in the upper part of the stomach to preserve the function of the stomach after surgery. An esophagogastrostomy is one of the common reconstruction methods for a proximal gastrectomy, but this method results in a high incidence of reflux esophagitis. This study was undertaken to compare subjective and functional results between esophagogastrostomy and jejunal interposition reconstructions. Materials and Methods: From June 1998 to December 2002, proximal gastrectomies were performed in 33 patients with tumors in the upper third of the stomach; 8 had reconstruction using jejunal interposition between the esophagus and the remnant stomach (JI group) while 25 had reconstruction using esophagogastrostomy (EG group). The postroperative courses of the patients were reviewed in terms of symptoms, weight changes, and endoscopic findings. Results: The mean age of the patients was 59 years; 26 were men and 7 were women. There were no significant differences in general complications, operating times, or histologic features between the two groups. Fifty-two percent (52%) of the EG group complained of dysphagia, and 16% them experienced heartburn and acid belching. Twelve percent (12%) of the JI group complained of dysphagia, but heartburn and acid belching did not occur. Incidences of reflux esphagitis (36%) and balloon dilatation for anastomotic stricture (16%) were more common in the EG group than in the JI group (0% and 12%). Conclusion: To prevent or minimize complications, such as reflux esophagitis and postoperative symptoms, a proximal gastrectomy with a jejunal interposition is an alternative method as an organ-preserving surgical strategy to improve quality of life for patients. (J Korean Gastric Cancer Assoc 2006;6:1-5)

우유에서 분리된 포도상구균속 세균의 항생제 감수성

김지훈,고문주,김가희,이승훈,최성숙,Kim, Ji-Hoon,Ko, Mun-Joo,Kim, Ka-Hee,Lee, Seung-Hoon,Choi, Sung-Sook 한국미생물학회 2010 미생물학회지 Vol.46 No.4

The prevalence and antimicrobial susceptibilities of Staphylococcal isolates from bovine milk samples were assessed. From January 2009 to October 2009, a total 287 bovine milk samples were randomly collected from 15 stock raising farms located in northern area of Kyunggi province and cultured for the presence of Staphylococci spp. A total 79 staphylococcal isolates were recovered from the milk samples. The predominant isolates were S. aureus (43.03%) and S. chromogenes (24.05%). Antimicrobial resistance patterns of 79 Staphylococcal isolates against ampicillin, chloramphenicol, ciprofloxacin, erythromycin, gentamicin, oxacillin, teicoplanin, tetracyclin, and vancomycin were tested. Staphylococcal isolates revealed the highest resistance to ampicillin (56.96%) and oxacillin (39.23%). Of 31 oxacillin resistance strains, 8 strains carry mecA gene which is responsible for methicillin resistance.

혈액질환에 속발하는 이차성 위암

김지훈,지성배,허훈,진형민,김욱,김동욱,이종욱,민우성,김춘추,전해명,Kim, Ji-Hoon,Jee, Sung-Bae,Huh, Hoon,Chin, Hyung-Min,Kim, Wook,Kim, Dong-Wook,Lee, Jong-Wook,Min, Woo-Sung,Kim, Choon-Choo,Jeon, Hae-Myung 대한위암학회 2007 대한위암학회지 Vol.7 No.4

Purpose: Patients with hematologic diseases such as chronic myeloid leukemia (CML) or chronic lymphoid leukemia (CLL) are known to have an increased chance of acquiring a secondary neoplasm. Stomach cancer is one of the most common malignant diseases in Korea, and we investigated whether the incidence of secondary stomach cancer in patients with a hematologic disease increases, in order to determine if a more intensive screening program for detecting secondary gastric cancer was required. We also investigated the safety of performing a gastrectomy in hematologic disease patients. Materials and Methods: From 1992 to 2006, the medical records of 8376 patients diagnosed with one of the six common hematologic diseases were reviewed. Results: Nine secondary stomach cancers were found among the 8376 patients during the 15-year observation period. No surgical-related complications occurred, and there was no recurrence of stomach cancer if detected early. Conclusion: It seems that a more intensive screening program for detecting secondary gastric cancer in hematologic disease patients is not required, and surgery is not risky in these patients.

후포분지 홀로세 퇴적물의 유기물에 대한 지화학 분석 결과 및 의미

김지훈,박명호,공기수,한현철,정태진,최지영,김진호,강무희,이치원,오재호,Kim, Ji-Hoon,Park, Myong-Ho,Kong, Gee-Soo,Han, Hyun-Chul,Cheong, Tae-Jin,Choi, Ji-Young,Kim, Jin-Ho,Kang, Moo-Hee,Lee, Chi-Won,Oh, Jae-Ho 대한자원환경지질학회 2010 자원환경지질 Vol.43 No.1

Geochemical approaches on the two recovered piston cores were performed to understand the characteristics of organic matters and the influence of the sea level variation of the East Sea in the Hupo Basin since the Holocene. The analyzing results on organic components (TOC and TN), and isotopic compositions of organic matters showed the variation to core locations and sampling depths. In core 08HZP-01, their values were gradually changed with depth from 4 mbsf to seafloor. However, rapid variation was observed at the boundary of 4.71 mbsf (meter below seafloor) in core 08HZP-03. Based on TOC/TN, $\delta^{13}C_{org}$ and $\delta^{15}N_{org}$, the origin of organic matters in the Hupo Basin can be divided into three groups; 1) predominant marine algae, 2) $C_3$ land plant, and 3) mixture of $C_3$ land plant and marine/freshwater algae. It is likely that the vertical and spatial variations of organic and isotopic compositions reflect the shifts in sedimentary environment (including sediment transportation) by ocean currents and sea-level changes and others during the Holocene period.

김제시 간척지역 천부 지하수내 철 환원작용 특성에 대한 고찰

김지훈,정태진,류종식,김락현,Kim, Ji-Hoon,Cheong, Tae-Jin,Ryu, Jong-Sik,Kim, Rak-Hyeon 대한자원환경지질학회 2013 자원환경지질 Vol.46 No.1

The study area is located on the western coastal region of Korea, partly had been reclaimed lands. Groundwaters of the coastal area show lower Eh and DO values (Eh: 0.57 V ${\rightarrow}$ 0.13 V, DO; 9.7 mg/l ${\rightarrow}$ 1.3 mg/l), and higher Fe concentrations (> 20 mg/l) than those of the inner land (< 0.3 mg/l), indicating that the redox condition of groundwater changes from oxic into suboxic/anoxic conditions as it flows from the inland toward the coastal area. In addition, Fe speciation of groundwater from the coastal area demonstrates that the most dissolved Fe exist as $Fe^{2+}$, reflecting that groundwater is under the anoxic condition to sufficiently occur Fe reduction. According to the result of Fe extraction with the sediment samples from three wells (A, B, C), the sediments provide enough $Fe^{3+}$ to occur the Fe reduction in the groundwater. Integrated all results of the groundwater and sediment, we infer that the Fe reduction to occur in groundwater is associated with the reclamation processes of the study area.

백부자산(白附子散)이 자외선 조사된 피부 손상과 색소침착에 미치는 영향

김지훈,홍승욱,Kim, Ji-Hoon,Hong, Seong-Ug 대한한방안이비인후피부과학회 2008 한방안이비인후피부과학회지 Vol.21 No.1

Objective : The purpose of this study is to examine the effects of Baickbujasan(BB) on the skin damage and depigmentation. Method : The inhibition of tyrosinase activity, melanogenesis and cell viability in cultured B16 melanoma cells were measured. In order to test effects of reduction of melanogenesis, B16 F-10 mouse melanoma stem line was employed to extract melanin from cultured cell, where BB was added or not, and was dissolved in alkali for colorimetric analysis. Also, in order to test skin alteration in C57BL/6 after UV irradiation, the animals were grouped into a UV urradiation group and UV irradiation after BB application group. Dopa oxidase tissue staining was excuted to invesitage the change in the distribution of active melanin cell. The distribution of active melanin cell in inner skin of iNOS after damage from UVB irradiation and the manifestation condition of P53 which takes part in natural death of keratinocyte were examined. Result : The results indicate that BB has significant effects on tyrosinase activity, and melanogenesis in vivo test. BB seems to reduce C57BL/6, external dermatological damage, for instance, erythematous papule, eczema, loss of keratinocyte, reduction in pus, and relieves dermatological damages. Conclusion : BB can be applied externally for UV protection and depigmentation.

말초성 안면신경마비의 한양방 협진치료에 관한 임상적 연구

김지훈,송재준,홍승욱,Kim, Ji-Hoon,Song, Jae-Jun,Hong, Seung-Ug 대한한방안이비인후피부과학회 2009 한방안이비인후피부과학회지 Vol.22 No.1

Objectives : Facial palsy is not uncommon disease and most patients with facial palsy are peripheral type, as in Bell' s palsy. In western medicine, oral steroid is the mainstay of the treatment. Recently, oriental-western treatment became one of the alternative modality for the treatment of the facial palsy. However, the treatment result and the degree of patient' s satisfaction were not evaluated. In this study, we tried to characterize the clinical characteristics, short-term recovery rate and degree of patient' s satisfaction after oriental-western medicine treatment on facial palsy of peripheral type. Methods : Between May 2008 and December 2008, we examined 16 patients who presented with facial palsy of peripheral type in Dongguk University Medical Center. Clinical characteristics and recovery rate was analyzed by retrospective chart review. The degree of patient' s satisfaction was measured by 5 point scale. Results : The causes of facial palsy were Bell' s palsy (87.5%) and the Ramsay-Hunt syndrome (12.5%). The highest age groups of facial palsy were 6th and 7th decades. Most frequent accompanying symptom was postauricular pain. After oriental-western medicine treatment, 10 patients (62.5%) showed recovery of facial palsy better than House-Brackmann grade 2. 11 patients (68.8%) were satisfied with the oriental-western medicine treatment. Conclusions : Considering the degree of patient' s satisfaction and treatment result, we believe that oriental-western treatment could be safe and reliable protocol for the treatment of facial nerve palsy of peripheral type.

2·3차원 준연계 모형을 이용한 남강댐 하류부 흐름 및 BOD 수송 해석

김지훈,송창근,김영도,서일원,Kim, Ji-Hoon,Song, Chang-Geun,Kim, Young-Do,Seo, Il-Won 한국수자원학회 2012 한국수자원학회논문집 Vol.45 No.3

The downstream of the Nam River Dam is crucial region for long-term water resource planning for Busan and Gyeongnam Province. Thus, the analysis of flow behavior and water quality is necessary for the sustainable surface water management and the control of pollutant source. In this study, the flow field and BOD transport at the downstream of Nam River Dam were analyzed by incorporating 2-D water quality model, RAM4 and 3-D water quality model, WASP with the hydrodynamic model, RAM2 and EFDC, respectively. The application of 2-D flow analysis model, RAM2 showed that velocity distributions at the five transverse sections of the meandering part closely followed the measured values by ADCP, and the flow field and overflow characteristic at the submerged weir showed satisfactory performance compared with the result of 3-D EFDC model. In addition, the BOD concentration field obtained by RAM2-RAM4 coupled modeling was in good agreement with the result by EFDC-WASP model throughout the computational domain. The hydrodynamic characteristic and water quality at the downstream reach of Nam River Dam are mainly influenced by the Dam discharge, and the water quantity is closely related to the water quality control and fishery environment at the lower part of Nakdong River. Therefore, when further quantitative analysis is necessary regarding these issues, 2-D semi-coupled modeling is recommended in terms of computational effectiveness and model application aspect.