논단 - 우리 농업의 미래 밝고 희망적이다

박해상,Park, Hae-Sang 한국작물보호협회 2010 자연과 농업 Vol.260 No.-

요즘 농업의 어려움은 주식시장에서 흔히 쓰는 "바닥 다지기"라고 표현하고 싶다. 이 바닥만 튼튼히 잘 다져 놓으면 미래농업은 우뚝 설 수 있으리 라고 본다. 미래농업은 농식품산업과 생명산업(BT), 두 축을 중심으로 괄목할 만한 성장을 할 것이다.

혼합모델 및 다중 가설 검정을 이용한 신호와 잡음의 분류

박해상,유시원,전치혁,Park, Hae-Sang,Yoo, Si-Won,Jun, Chi-Hyuck 한국통계학회 2009 응용통계연구 Vol.22 No.4

본 논문은 신호와 잡음이 혼합된 관측치로부터 신호 관측치를 분류하는 문제를 다룬다. 잡음은 가우시안 분포를 따르고 신호는 감마 분포를 따른다고 가정할 때 관측치의 분포는 가우시안과 감마의 혼합 분포를 따르게 된다. EM 알고리즘을 통해 혼합 모델의 모수를 추정하고 신호 및 잡음을 분류하는 것을 다중 가설 검정으로 간주하여 베이즈 오류를 바탕으로 분류를 위한 경계치를 설정한다. 제안하는 방법을 분광 데이터에 근거하여 철강 제품에서 개재물 유무를 검출하는 문제에 적용하였고 별도의 시뮬레이션 데이터를 통해 성능의 우수성을 보였다. A problem of separating signals from noises is considered, when they are randomly mixed in the observation. It is assumed that the noise follows a Gaussian distribution and the signal follows a Gamma distribution, thus the underlying distribution of an observation will be a mixture of Gaussian and Gamma distributions. The parameters of the mixture model will be estimated from the EM algorithm. Then the signals and noises will be classified by a fixed threshold approach based on multiple testing using positive false discovery rate and Bayes error. The proposed method is applied to a real optical emission spectroscopy data for the quantitative analysis of inclusions. A simulation is carried out to compare the performance with the existing method using 3 sigma rule.

Positive false discovery rate를 활용한 새로운 군집 분석

박해상(Hae-sang Park),전치혁(Chi-Hyuck Jun) 한국경영과학회 2010 한국경영과학회 학술대회논문집 Vol.2010 No.6

Clustering analysis is an unsupervised learning technique for partitioning objects into several clusters so that objects within a cluster have similarity in comparison to one another, but are dissimilar to objects in other clusters. Traditional clustering methods assign all objects into one of the clusters, but in this paper, we assume that noise data are present which do not belongs to any clusters. Assuming the data follows a mixture of Gaussian distributions, the parameters of the mixture model are estimated from the EM algorithm. We calculate the p-value through Monte Carlo method using the estimated probability density function and estimate positive false discovery rate (pFDR). By the proposed procedure, the objects are clustered and classified into data or noise simultaneously according to the specified pFDR. We apply the proposed method to real data and simulation data, which shows that it performs reasonably by controlling the false discovery rate.

Positive false discovery rate를 활용한 새로운 군집 분석

박해상(Hae-sang Park),전치혁(Chi-Hyuck Jun) 대한산업공학회 2010 대한산업공학회 춘계학술대회논문집 Vol.2010 No.6

Clustering analysis is an unsupervised learning technique for partitioning objects into several clusters so that objects within a cluster have similarity in comparison to one another, but are dissimilar to objects in other clusters. Traditional clustering methods assign all objects into one of the clusters, but in this paper, we assume that noise data are present which do not belongs to any clusters. Assuming the data follows a mixture of Gaussian distributions, the parameters of the mixture model are estimated from the EM algorithm. We calculate the p-value through Monte Carlo method using the estimated probability density function and estimate positive false discovery rate (pFDR). By the proposed procedure, the objects are clustered and classified into data or noise simultaneously according to the specified pFDR. We apply the proposed method to real data and simulation data, which shows that it performs reasonably by controlling the false discovery rate.

독립성분분석을 이용한 혼합물의 미지성분비율 예측

이혜선,송재기,박해상,전치혁,Lee Hye-Seon,Song Jae-Kee,Park Hae-Sang,Jun Chi-Hyuck 한국통계학회 2006 응용통계연구 Vol.19 No.1

Independent component analysis (ICA) is a statistical method for transforming an observed high-dimensional multivariate data into statistically independent components. ICA has been applied increasingly in wide fields of spectrum application since ICA is able to extract unknown components of a mixture from spectra. We focus on application of ICA for separating independent sources and predicting each composition using extracted components. The theory of ICA is introduced and an application to a metal surface spectra data will be described, where subsequent analysis using non-negative least square method is performed to predict composition ratio of each sample. Furthermore, some simulation experiments are performed to demonstrate the performance of the proposed approach. 독립성분분석은 차원이 높은 다변량데이타로부터 기저구조를 형성하는 독립성분을 분리하는데 사용되는 기법으로서 패턴인식, 예측 등 2차적 분석을 위한 1차 분석단계에서 사용할 수 있다. 본 연구에서는 독립성분분석을 이용하여 여러 혼합물 데이터로부터 독립성분을 분리한 다음 각 구성성분의 혼합비율을 예측하는 절차를 제안한다. 적용예로서 도금강판의 엑스선 회절강도값으로부터 여러가지 상을 분리한 다음 비음최소자승법을 이용하여 각 상의 분율을 예측하였으며, 이러한 제안방안의 타당성 평가를 위하여 모의 실험을 실시하였다.

대량 폐동맥 혈전색전증으로 인한 심정지 환자의 심폐소생술 - 혈전용해제사용 경험 2 예 -

조준휘(Jun Hwi Cho),황성오(Sung Oh Hwang),이강현(Kang Hyun Lee),이진웅(Jin Woong Lee),이서영(Seo Young Lee),박해상(Hae Sang Park),김성환(Seong Whan Kim) 대한응급의학회 2002 대한응급의학회지 Vol.13 No.1

The massive pulmonary thromboembolism is serious illness that can lead to death within an hour after its occurrence. The incidence of cardiac arrest caused by massive pulmonary thromboembolism has been known as about 7%. Invasive therapeutic modalities to treat massive pulmonary thromboembolism during cardiac arrest including thoracotomy or cardiopulmonary bypass have been shown little effect. Administration of a thrombolytic agent is an alternative choice of treating massive pulmonary thromboembolism during cardiac arrest. This report describes our experience of cases with massive pulmonary thromboembolism that were treated with administration of a thrombolytic agent during CPR.

심정지 이후에 발생하는 간 기능 장애의 양상과 이에 영향을 주는 요소

박해상,황성오,김현,최한주,안희철,이서영,장용수,이강현 대한응급의학회 2002 대한응급의학회지 Vol.13 No.4

Purpose: Little is known about the clinical courses or outcomes of abnormalities of liver function in patients resuscitated after cardiac arrest. We conducted this study to investigate the clinical features and courses of abnormalities of live function during the post-resuscitation period. Methods: Twenty-five patients (18 males, mean age: 43 years), who had survived cardiac arrest, were enrolled in this study. Blood samples for the liver function test were obtained immediately and at 1, 2, 4, 7, 10, and 14 days after return of spontaneous circulation. Clinical characteristics, variables associated with cardiac arrest, data during resuscitation, and clinical course during the post-resuscitation period were obtained from our cardiac arrest database. Results: Seventeen patients (68%) had abnormalities of live function. Those abnormalities included, in order of frequency, increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (γ-GT), or total bilirubin in blood, and a decrease in serum albumin. the highest values of AST, ALT, γ-GT, and total bilirubin were observed on the second day of postresuscitation period. The abnormalities were normalized in all patients within two weeks after the cardiac arrest. There was not deaths from hepatic failure. There was no difference in downtime, CPR time, number of defibrillations, dose of administered epinephrine, blood pressure, or heart rate after return of spontaneous circulation between the patients with normal liver function and the patients with abnormal liver function (increase of AST or ALT > 50 U/L.) Multiple logistic regression analysis revealed that the duration of cardiac arrest was associated with the elevation of liver enzymes. Conclusion: Hepatic dysfunction after cardiac arrest is a transient, benign phenomenon. Development of hepatic dysfunction was associated with the duration of cardiac arrest.

비외상성 두개내 출혈 환자에서 심근손상의 발생과 예후에 미치는 영향

강구현,황성호,이강현,조준휘,김성환,문중범,박해상,이서영,이성수,김헌주 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

Objective: The aim of this study was to investigate the clinical significance of myocardial injuries in patients with nontraumatic intracranial hemorrhage by identifying the occurrence of myocardial injury and defining its correlation with subsequent cardiovascular events. Subjects and methods: One hundred twenty-four patients with nontraumatic intracraninal hemorrhage presented to the emergency department within six hours from onset of symptoms were enrolled. Brain CT, serial electrocardiography, and echocardiography were done at the emergency center. Blood samples for troponin I and creatine kinase(CK)-MB were drawn immediately and eight hours after admission, Troponin I and CK-MB were measured using a chemiluminescent immunoassay, respectively. Results: Electrocardiographic and echocardiography abnormalities were found in 65 cases(52.4%) and 21 cases(17%), respectively. Serum troponin I and creative kinase-MB were increased in 35 cases (28.2%) and in 58 cases(46.8%), respectively. Abnormal findings of echocardiography and ECG, as well as elevated levels of serum troponin I and creative kinase-MB, were associated with an increased risk of cardiovascular event and survival. Logistic regression analysis revealed that an abnormal echcocardiographic finding and elevation of serum troponin I were factors associated with the occurrence an adverse cardiovascular event and that electrocardiographic abnormalities and initial mental status were factors associated with poor prognosis. Conclusion: This study reveals that actual myocardial injury develops in a significant proportion of patients with nontraumatic intracranial hemorrhage and that the development of the myocardial injury is associated with an adverse cardiovascular event that occurs during admission.

심폐소생술 중 하행 대동맥 내 압력 차이 발생의 혈역학적 의의

황성오,박해상,이서영,안희철,김현,이강현,유병수,이승환,윤정한,최경훈 대한응급의학회 2002 대한응급의학회지 Vol.13 No.3

Purpose: There have been no reports concerning the role of the aorta in explaining why blood flow is low below the diaphragm and a pressure gradient is present between central and peripheral arteries during standard cardiopul-money resuscitation (CPR). The aim of this study was to assess the morphologic changes of the descending thoracic aorta and its effect on aortic pressure during precordial chest compression in cardiac arrest victims. Methods: Twelve patients with non-traumatic cardiac arrest (8 males, mean age: 58 years) were enrolled. Transesophageal echocardiography was performed to verify the morphologic changes of the descending thoracic aorta during standard manual CPR. The pressure gradient across the maximally compressed site of the aorta was measured by pullback tracing using a pigtail catheter. Results: Focal compression and deformation of the descending thoracic aorta was uniformly observed in all patients during compression systole. The mean systolic blood pressure of the descending thoracic aorta proximal and distal to the maximally compressed site was 135±36 mmHg and 115±21 mmHg, respectively. The mean systolic pressure gradient across the maximally compressed site was 20.5±17.7 mmHg. During compression systole, the pressure gradient between the right atrium and the descending thoracic aorta proximal to the maximally compressed site during compression systole was 49±12 mmHg while pressure gradient between the right atrium and the descending thoracic aorta distal to the maximally compressed site was 29±8 mmHg. Conclusion: We found that the descending thoracic aorta was focally compressed and that a pressure gradient developed across the maximally compressed site during compression systole. This may contribute to limiting blood flow to the subdiaphragmatic region during standard manual CPR in humans.

중증 스키 및 스노우 보드손상의 특성 : 6년간 경험 6 Years Experience

이강현,김성환,박해상,조준휘,황성오,이종민,이영희,임경수 대한스포츠의학회 2000 대한스포츠의학회지 Vol.18 No.2

Objective : Evaluation of the cause of the cause of severe injuries in fatal downhill skiing of snowboarding accidents in important to prevention. But the incidence of sever injuries form snowboarding and skiing is unknown in Korea. The purpose of this study was to evaluate the severs skiing and snowboarding injuries. Methods : The medical records of twenty-one consecutive patients(ISS≥10) with skiing or snowboarding injuries who visited to the emergency department of Wonju Christina Hospital of post that located in the three Ski Resrots(Young Pyong, Sung Woo, Phoenix Park Ski Resort Town) from Nov. 1995 to Mar. 2000 were reviewed for following information: age, injury mechanisms, Injury Severity Score(ISS), Glasgow Coma Scale(GCS) and cause of death. Results : Among the patients, 15 patients(71.4%) injured from skiing and 6 patients(28.6%) injured from snowboarding. Of the patients, 57% were male with mean age of 28±9, and mean ISS of 23±9, mean GCS 11±5. There were 14(66.6%) head injuries, 4(19.0%) spine injuries, 4(19.0%) abdominal organ injuries, 2(9.5%) chest injury. There were 4 deaths(19.0%). The cause of deaths was head injury. Conclusion : The cause of all deaths associated with skiing or snowbording was head injury. Our results suggest that death during snowboarding or skiing can be reduced if skier or snowboarder use protective helmet for head trauma.