• 한국지능시스템학회논문지
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• 제20권2호
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• pp.165-172
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• 2010

임상 데이터마이닝에서 최적의 특징 집합을 선택하는 것은 주어진 데이터로부터 생성된 모델의 복잡성을 줄일 뿐만 아니라 유용성을 향상시키는 데에 매우 중요하고, 선택된 특징들의 임계값은 질병의 감별진단을 위해 임상 전문가의 결정기준으로 사용된다. 본 논문에서는 데이터의 공간적인 분포, 즉 중첩영역에서 중복 속성값을 포함하는 데이터의 분리성 정도를 평가함으로써 연속형 속성을 가진 데이터에 대한 퍼지 이산화기법을 제안한다. 제안된 방법에서 중복 속성값의 가중치 평균값은 각 특징의 임계값(즉 경계값)을 결정하기 위해서 사용되었고, 러프집합은 전체 특징들 중에서 중요특징들의 집합을 선택하기 위해서 이용하였다. 제안된 방법의 타당성을 검증하기 위해 호흡곤란을 주호소로 내원한 668명의 환자 데이터를 근거로 3가지 이산화방법과 제안된 이산화방법에 대한 실험을 수행하였다. 실험결과, 퍼지분할을 기반으로 한 이산화방법이 하드분할을 기반으로 한 이산화방법에 비해서 평균 분류정확도와 G-mean 성능에서 보다 좋은 결과를 제공함을 확인하였다.

• 전자공학회논문지SC
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• 제49권2호
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• pp.46-54
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• 2012

본 논문에서는 연속 가압방식으로 측정된 맥파 신호의 분석에 적합한 시작점 검출 알고리즘을 제안한다. 연속 가압방식은 가압의 크기를 조금씩 증가시키면서 맥파 신호를 측정하는 방식인데 이를 이용하면 가압크기에 대응하는 맥파 신호의 분해능이 크게 향상되기 때문에 현재 상용맥진기의 맥파 측정방식인 단계별 가압방식의 정확성과 신뢰성 문제를 해결할 수 있다. 시작점 검출을 위해서 고속 푸리에 변환을 이용한 주기계산, Center-to-edges 방법의 피크 검출, 기저선 보정, 접선 교점 방법에 의한 시작점 검출, 분석 구간 설정을 순차적으로 적용한 알고리즘을 개발하였다. 30명의 피험자를 대상으로 실험한 결과 제안된 알고리즘의 정확도는 99.46%, 민감도는 99.51%로 나타났는데 이는 기존 알고리즘보다 정확도 4.82%, 민감도 2.46%가 향상된 결과이다. 본 연구에서 제안한 연속 가압방식의 맥파 측정방법과 맥파 시작점 검출 알고리즘을 사용한다면 맥파 특징점의 정확한 검출은 물론 허실맥이나 부침맥 등의 맥상 판별 정확성을 높일 수 있을 것으로 기대된다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권7호
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• pp.612-624
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• 2005

본 논문에서는 PET-CT 뇌 영상융합을 위해 가우시안 가중치 거리지도를 이용한 표면기반 영상정합을 제안한다. 제안방법은 중요 세 단계로 표면 특징점 추출, 가우시안 가중치 거리지도 생성, 가중치기반 유사도 평가로 구성된다. 첫째, PET 영상과 CT 영상에서 삼차원 역 영역성장법을 이용하여 머리영역을 분할하고 머리 영역과 같이 분할된 잡음 영역을 영역성장법기반 레이블링을 이용한 영역 크기 비교를 통해 제거한 후 선명화 처리 필터를 적용하여 머리 표면 특징점을 추출한다. 둘째, CT 영상에서 추출한 표면 특징점에 가우시안 가중치 거리지도를 생성하여 큰 변위에서도 최적의 위치로 견고하게 수렴하도록 한다. 셋째, 가중치기반 상호상관관계는 PET 영상에서 추출한 표면 특징점과 대응되는 CT 영상의 가우시안 가중치 거리지도를 이용하여 최적 위치를 탐색한다. 본 논문에서는 제안방법의 정확성과 견고성 검사를 위해 인공데이타를 이용하고, 수행시간과 육안평가를 위해 임상데이타를 이용한다. 정확성 검사는 임의로 변환된 인공데이타에 제안방법을 적용한 후 추출된 최적화 변환벡터와의 오차를 제곱근평균제곱오차를 이용하여 평가한다. 견고성 검사는 큰 변위와 잡음을 가지는 인공데이타에서 가중치기반 상호상관관계가 최적의 위치에서 최대를 이루는지를 평가한다 실험 결과 제안한 표면기반 영상정합이 기존 표면기반 영상정합보다 정확하고 견고하게 수렴됨을 알 수 있다.

• Radiation Oncology Journal
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• 제34권4호
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• pp.239-249
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• 2016

Tumor hypoxia, a common feature occurring in nearly all human solid tumors is a major contributing factor for failures of anticancer therapies. Because ionizing radiation depends heavily on the presence of molecular oxygen to produce cytotoxic effect, the negative impact of tumor hypoxia had long been recognized. In this review, we will highlight some of the past attempts to overcome tumor hypoxia including hypoxic radiosensitizers and hypoxia-selective cytotoxin. Although they were (still are) a very clever idea, they lacked clinical efficacy largely because of 'reoxygenation' phenomenon occurring in the conventional low dose hyperfractionation radiotherapy prevented proper activation of these compounds. Recent meta-analysis and imaging studies do however indicate that there may be a significant clinical benefit in lowering the locoregional failures by using these compounds. Latest technological advancement in radiotherapy has allowed to deliver high doses of radiation conformally to the tumor volume. Although this technology has brought superb clinical responses for many types of cancer, recent modeling studies have predicted that tumor hypoxia is even more serious because 'reoxygenation' is low thereby leaving a large portion of hypoxic tumor cells behind. Wouldn't it be then reasonable to combine hypoxic radiosensitizers and/or hypoxia-selective cytotoxin with the latest radiotherapy? We will provide some preclinical and clinical evidence to support this idea hoping to revamp an enthusiasm for hypoxic radiosensitizers or hypoxia-selective cytotoxins as an adjunct therapy for radiotherapy.

• 대한족부족관절학회지
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• 제9권2호
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• pp.162-166
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• 2005

Purpose: To analyze the clinical and radiological feature of Os subfibulare and to evaluate the results after anatomical reduction and internal fixation with bone graft for Os subfibulare. Materials and Methods: Forty-two cases, which underwent anatomic reduction and bone graft for Os subfibulare from October 1998 to September 2004 were reviewed. We analysed preopertive symptoms and onset of symptoms and radiologically measured the size and amounts of displacement of Os subfibulare under the inversion stress. Postoperatively we evaluated the clinical results measured by Hasegawa method and evidence of union. Results: Preoperatively there were only pain around the lateral malleolus in 16 cases, only instability of ankle joint in 3 cases, and pain and instability in 23 cases. The age of symptom onset averaged 23 years(range, 13-38 years). Radiographically Os sufibulare anteriorly located from lateral malleolus were in 40 cases, posteriorly situated in 2 cases. The size of Os subfibulare ranged from $1{\times}4\;mm$ to $8{\times}17\;mm$. In 22 cases of inversion stress view, displacement of the Os sbufibulare averaged $1.5{\pm}1.1\;mm$ (0 to 5 mm). The postoperative clinical results were excellent in 41 cases, poor in 1 case. There were complications of 1 case of irritation of sural nerve, 1 case of nonunion. Conclusion: Anatomic reduction and bone graft is effective treatment method for symptomatic Os subfibulare.

• Childhood Kidney Diseases
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• 제21권2호
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• pp.61-68
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• 2017

Purpose: To investigate differences in clinical features, blood/urinary findings, and prognosis in different age groups of patients with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods: A total of 469 patients with HSP were analyzed retrospectively from June 2003 to February 2016. We classified patients into child or adult groups based on their age. Results: The adult group had more patients with anemia (child vs. adult; 7.5% vs. 16.4%), and higher immunoglobulin A (IgA) (30.0% vs. 50.0%) levels, C-reactive protein (34.2% vs. 54.0%) and uric acid (3.1% vs. 12.1%) levels than the child group. The child group was highly positive for Mycoplasma pneumoniae immunoglobulin M (IgM) (34.4%). More patients in the child group presented with high levels of antistreptolysin O (24.7% vs. 2.9%) and high C4 (11.5% vs. 4.2%). Low C3 (1.1% vs. 10.2%) levels, and renal involvement with gross hematuria (8.6% vs. 21.5 %), nonnephrotic proteinuria (1.1% vs. 11.2%), and nephrotic syndrome (1.1% vs. 6.0%) were common in the adult group. Adults also had poorer renal outcomes [persistent hematuria/proteinuria (10.5% vs. 32.8%), and chronic kidney disease (0% vs. 11.2%)] than the child group. Risk factors for renal involvement such as older age and higher level of uric acid were only found in the child group. The risk factors for poor renal outcome were nephrotic syndrome in the child group and gross hematuria in the adult group. Conclusion: In this study, child and adult groups presented with different clinical manifestations of HSP. We found that risk factors for renal involvement included age and high uric acid level in the child group. Moreover, nephrotic syndrome in the child group and gross hematuria in the adult group increased the risk of poor renal outcome.

• Journal of Yeungnam Medical Science
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• 제30권2호
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• pp.95-100
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• 2013

Background: This study was performed to investigate the epidemiologic and clinical features of acute respiratory viral infection in hospitalized children. Methods: From 2010 to 2012, we tested nasopharyngeal swab specimen in 1,584 hospitalized children with multiple real-time polymerase chain reactions to identify 10 kinds of respiratory viruses (including influenza virus A, B (FluA, FluB), respiratory syncytial virus (RSV), human metapneumovirus (MPV), adenovirus (AdV), human coronavirus (CoronaV), human enterovirus (HEV), human bocavirus (HBoV), parainfluenza virus (PIV), and human rhinovirus (Rhinovirus)). We analyzed the positive rate, annual and seasonal variations, and clinical features (respiratory tract and non-respiratory tract) according to the retrospective review of medical records. Results: Respiratory viruses were detected from 678 (42.8%) of 1,584 patients. The most common detected virus was RSV (35.0%), and then AdV (19.0%), HEV (18.1%). The critical period of the respiratory viral infection was during the first 12 months of a child's life. PIV increased by 8.4%, 12.1%, and 21.1% annually. Bronchiolitis was most frequently caused by RSV, and croup was frequently caused by PIV. The most common cause of meningitis was HEV. Hepatitis-associated respiratory virus was developed 111 in 678 cases. Conclusion: Although this study was confined to a single medical center for three years, we identified the epidemiology and clinical feature of respiratory viruses in Daegu from 2010 to 2012. Future surveillance will be necessary for annual and seasonal variations.

• 대한임상검사과학회지
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• 제40권1호
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• pp.41-47
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• 2008

Colorectal carcinoma is occurred frequently to Korean and so ranked the fourth from various cancers. Due to western dietary life, this cancer has been increased continually. Therefore, the study will be needed to find a candidate gene involved in the development and progression of colorectal carcinoma and to diagnose and treatment helpfully. The striking feature from cancer suppressor genes is known for LOH (loss of heterozygosity), which is the method to find allele genetic loss or mutation of cancer cell. The purpose of this study was designed to find a carcinogenic gene from colon cancer using microsatellite marker on 17th and 18th chromosome from 30 subjects. The LOH was investigated in order of D18S59 57% (17/30), TP53CA 50% (15/30), D18S68 47% (14/30), D18S69 43% (13/30). The genetic mutation depends on loci of colorectal carcinoma was shown higher with 2.44 from colon cancer than with 1.25 from right colorectal carcinoma (p<0.032). The genetic mutation with lymph nodes was investigated higher with 2.69 at mutated group than with 1.14 at non-mutated group (p<0.003). At genetic mutated pattern depends on disease stage, there was higher significant difference at III-IV stage 2.50 than that of I-II stage 1.17, respectively (p=0.015). There was no difference at comparison between histological classification and serological CEA increase. The loss on 18q21 found in this study is highly recurrence loci and was observed 43% for Korean with high recurrence. Therefore, LOH is a very useful tool to detect 18q21 loci in clinical application, prior to the treatment of colorectal carcinoma. After the operation of colorectol carcinoma, the efficient application using LOH at operated part tissue which is designed to protect the recurrence as well as its cure will be needed.

• 정신신체의학
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• 제5권1호
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• pp.118-122
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• 1997

저자들은 13년전 심한 산후 출혈 후에 서서히 진행된 성선, 갑상선, 부신피질호르몬결핍증상과 함께 피해망상, 환청과 이에 따른 행동, 심한 불면증, 정신운동의 지체, 사회적 철퇴 등의 증상을 보인 51세 여자환자의 증례를 경험하였다. 환자는 일견 심한 정신병적 우울증의 양상을 보여 정신과에 입원하였으나 자세한 병력 청취 및 임상양상의 관찰로 내과적 질환에 의한 정신증의 가능성이 고려되었고, 호르몬 검사상 범뇌하수체기능 부전소견과 저혈당증 및 저나트륨혈증 등을 나타내 Sheehan시 증후군의 진단이 가능하였다. 갑상선과 부신피질호르몬의 투여 기타 보존적인 치료에 의해 정신과적증상을 포함한 제반 임상증상이 1주이내에 호전되었다. 저자들은 본 증례의 보고를 통해 정신과 환자에 대한 임상적 접근에서 간과되기 쉬운 내재된 내과적 문제의 감별의 중요성을 다시 한 번 강조하고자 한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권5호
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• pp.360-364
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• 2021

Objectives: The purpose of this study was to evaluate the clinical and radiographic characteristics of idiopathic bone cavity (IBC) to determine the effect of surgical intervention on the process of healing. Materials and Methods: All cases diagnosed with IBC during the period of 2011 to 2020 at our Department of Oral and Maxillofacial Surgery were searched. Ninety cases were retrieved. The features evaluated were sex, age, contour of the lesion, number of teeth involved, site, history of trauma, and postoperative healing pattern. The significance of differences was assessed by Mann-Whitney U test and chi-square test. Results: The female:male ratio showed no predilection toward either sex (0.9:0.8). The mean age of the collected sample was 22.05±14.38 years, and the age ranged from 10 to 58 years. All cases presented in the mandible and showed well-circumscribed radiolucency. Margins were either scalloped or round in shape, and the size varied from one tooth to six teeth involvement. Seventy cases involved three or fewer roots. Three cases showed bilateral lesion. Four cases had a history of trauma at the area of the lesion. Fifty-one cases were followed for six months after surgery, and all showed increased bone density at the lesion. Conclusion: There is no definitive radiological or clinical feature of IBC. Considering the diversity of clinical and radiological features, such a diagnosis relies primarily on surgical findings of an empty bone cavity with no epithelial lining. Our data suggest that surgical intervention be the first choice of treatment as opposed to observation.