사업장폐기물 통계조사의 의의와 발전방향

나정균,Na, Jeong-Gyun 환경보전협회 2002 환경정보 Vol.24 No.3

방사선 손상으로 사료되는 지연괴사성 백질뇌병증 1예

나정균,정원영,조경원 대한신경과학회 1994 대한신경과학회지 Vol.12 No.3

Rainstem encophalitis mimicking Miller Fisher Syndrome

나정균,정원영,조경원,임건한 대한신경과학회 1994 대한신경과학회지 Vol.12 No.4

대기 외란 상황에서 결맞음 빔결합을 통한 광학 에너지의 전달 방법 수치 모델링

나정균,김병호,차혜선,정윤찬 한국광학회 2020 한국광학회지 Vol.31 No.6

In this paper, the effect of atmospheric turbulence is numerically modeled and analyzed via a phase-screen model, in regard to long-range optical energy transfer using coherent beam combination. The coherent-beam-combination system consists of three channel beams pointing at a target at a distance of 1-2 km. The phase and propagation direction of each channel beam are assumed to be corrected in an appropriate manner, and the atmospheric turbulence that occurs while the beam propagates through free space is quantified with a phase-screen model. The phase screen is statistically generated and constructed within the range of fluctuations of the structure constant   from 10 −15 to 10 −13 [   ]. Particularly, in this discussion the shape, distortion, and combining efficiency of the 3-channel combined beam are calculated at the target plane by varying the structure constant used in the phase-screen model, and the effect of atmospheric turbulence on beam-combination efficiency is analyzed. Analysis with this numerical model verifies that when coherent beam combination is used for long-range optical energy transfer, the received power at the target can be at least three times the power obtainable by incoherent beam combination, even for maximal atmospheric fluctuation within the given range. This numerical model is expected to be effective for analyzing the effects of various types of atmospheric-turbulence conditions and beam-combination methods when simulating long-range optical energy transfer.

추골기저동맥의 방추상 동맥류에 관한 연구

나정균,정원영,조경원,임건한 조선대학교 1993 The Medical Journal of Chosun University Vol.18 No.2

Fusiform aneurysm, elongation, widening and tortusoity of the intracranial vessels, often causes focal neurologic symptoms due to compression of neighbouring neural tissue or tyrombotic infarction. We retrospectively evaluated the clinical features and therapeutic ourcomes in five cases with fusiform aneurysm of the vertebrobasilary artery(VBFA) among central vertigo patients. Four VBFAs were detected in 164 cases with Vertebrobasilaty insufficiency (VBI) and Vertebrobasilary transient ischemic attack (VBTIA) and one was detected incidentally in anterior cerebral artery territory infarction patient. The results were summarized as follows : 1) There were 3 male and 2 females with average age of 55.6 years old. 2) Vertigo is a most frequent manifestation of these V BFA patients. 3) Four cases, one of whom showed no abnormal finding on previous computed tomographic scan (CT), were detected actatic basilar artery on magnetic rosonance imaging(MRI) and one case was detected on CT. 4) All five patients received anticoagulants and antiplatelet agents without recurrence during a mean follow-up period of 7.2 months. In summary, Vertigo is a frequent manifestation of these VBFA patients. So it is suggested that VBFA is not rare and is recommended MRI in central vertigo patients.

증여의제와 완전포괄주의에 관한 소고

나정균 서울市立大學校 經商大學 稅務學科 2004 稅務學論集 Vol.17 No.1

증여의제와 완전포괄주의에 관한 소고

급성 뇌경색후 사망에 대한 조기 예측인자

나정균,김진호,정원영 朝鮮大學校 附設 醫學硏究所 1996 The Medical Journal of Chosun University Vol.21 No.1

The risk of death from stroke is highest in the first few weeks after acute stroke, although mortality rate within a month varied. However there have been few reports of early predictors of death after acute cerebrovascular accident(CVA). The aim of this study was to determine which variables, of those easily assessable during the first 24 hours after acute stroke onset, would be predictors of death at 3 months after stroke. Ninty-eight consecutive patients with an acute ischemic event were evaluated within 24 hours after symptom onset. The following potential predictors of outcome were tested by means of Mann-Whitney U-test and ANOVA analysis: age. sex. past history of risk factors for CVA(such as hypertension, diabetes mellitus. atrial fibrillation, Previous stroke, smoking. drinking and ischemic heart disease), neurologic focal deficits according to National Institute of Health sca1e(NIH scale: its' subitems are consist of consciousness level, orientation, eye opening, motor weakness, ataxia, aphasia, dysarthria, cranial nerve palsy and neglect), urinary incontinence, dysphagia. systolic and diastolic blood pressure, laboratory findings (fasting blood sugar, cholesterol, triglycehde, hematocht). types of stroke, infarct size. and modified Rankin scale at stroke onset. The bivariate analysis between group A(those who survived more than 3 months after a cute CVA) and group B (those who died within 3 months after CVA onset) revealed that death at 3 months depended on the history of previous stroke(p< 0.001). the level of consciousness(p< 0.01). urinary incontinence(p< 0.01), presence of dependent hemip1egia(p< 0.05), myocardial ischemia on e1ectrocardiography(EKG)(p< 0.05). and fasting blood sugar(p< 0.05).

뇌졸증 후유증 환자에 대한 Idebenone의 효과와 안전성에 관한 연구

정원영,나정균,임건한 조선대학교 1994 The Medical Journal of Chosun University Vol.19 No.2

To evaluate the clinical efficacy and safety of Idebenone in 19 patients with the sequelae of the Cerebrovascular accidents(CVA). we conducted an open label trial of Idebenone for 8 weeks. The protocol consists of baseline. 4 weeks and 8 weeks evaluation. We evaluated psychic signs. subjective symptoms. activities of daily life and neurologic signs. The results were as follows : 1. Eight weeks after the trial. the majority of subjects(73.7%) were improved slightly or better. 2. At final evaluation, the slight improvement or better of psychic signs, subjective symptoms, activities of daily life and neurologic signs were 75.0%, 60.0%, 79.7% and 70.0%, respectively. 3. The adverse reactions were observed in 2 cases. one was headache and the other Gl trouble. There also were noticed transient elevation of SGOT/SGPT in one case. According to these results, it was concluded that administration of Idebenone after the acute phase of CVA is effective and safe.

몬테 카를로 복사 전달 행렬 방법을 사용한 산란 대기에서 동작하는 단거리 3차원 플래시 라이다 시스템의 수치적 모델링

안해찬,나정균,정윤찬,An, Haechan,Na, Jeongkyun,Jeong, Yoonchan 한국광학회 2020 한국광학회지 Vol.31 No.2

3차원 플래시 라이다 시스템(3D flash LIDAR system)에서의 대기 산란을 해석하기 위해 몬테 카를로 복사 전달(Monte Carlo radiative transfer, MCRT) 방법을 바탕으로 수정된 수치 해석 모델인 MCRT 행렬 방법을 논의한다. MCRT 방법을 바탕으로 라이다 신호의 복사 전달 함수를 행렬 형태로 구성하며, 이는 특성 응답에 해당한다. 근축 근사에 기반하여 본 특성 응답 행렬의 중첩 및 합성곱 연산을 활용함으로써 확장된 전반적인 플래시 라이다의 전산 모사 모델을 개발한다. MCRT 행렬 방법은 기존의 몬테 카를로 기반 방법들에서 과도하게 증가할 수 있는 개별 라이다 신호의 추적을 대폭 경감시킨다. 그 결과 본 방법은 다양한 산란 조건 및 라이다 시스템 구성 환경에서도 그 신호 응답을 빠르게 획득할 수 있는 특징을 지닌다. 본 논문에서는 MCRT 행렬 방법에 기반한 전산 모델을 이용하여 상이한 대기 환경 조건에서 동작하는 3차원 플래시 라이다 시스템을 그 산란 조건, 즉, 그 가시거리에 따른 산란 계수를 달리하며 모사하고, 플래시 라이다 신호의 신호대잡음비의 악화, 신호 오류, 시공간적 확산 및 시간 지연 등 시스템상에서의 산란 효과에 의해 나타나는 다양한 현상을 수치적으로 분석한다. MCRT 행렬 방법은 자율 주행을 위한 플래시 라이다 시스템을 포함해 다양한 라이다 시스템을 분석하는데 매우 효과적으로 사용될 수 있을 것으로 기대된다. We discuss a modified numerical model based on the Monte Carlo radiative transfer (MCRT) method, i.e., the MCRT matrix method, for the analysis of atmospheric scattering effects in three-dimensional flash LIDAR systems. Based on the MCRT method, the radiative transfer function for a LIDAR signal is constructed in a form of a matrix, which corresponds to the characteristic response. Exploiting the superposition and convolution of the characteristic response matrices under the paraxial approximation, an extended computer simulation model of an overall flash LIDAR system is developed. The MCRT matrix method substantially reduces the number of tracking signals, which may grow excessively in the case of conventional Monte Carlo methods. Consequently, it can readily yield fast acquisition of the signal response under various scattering conditions and LIDAR-system configurations. Using the computational model based on the MCRT matrix method, we carry out numerical simulations of a three-dimensional flash LIDAR system operating under different atmospheric conditions, varying the scattering coefficient in terms of visible distance. We numerically analyze various phenomena caused by scattering effects in this system, such as degradation of the signal-to-noise ratio, glitches, and spatiotemporal spread and time delay of the LIDAR signals. The MCRT matrix method is expected to be very effective in analyzing a variety of LIDAR systems, including flash LIDAR systems for autonomous driving.

렌즈 수차에 의한 타일형 빔 결합 출력 감쇠와 왜곡 현상 분석

김병호,나정균,정윤찬 한국광학회 2020 한국광학회지 Vol.31 No.6

In this paper, we quantitatively analyze the effect of lens aberration on the degradation of beam-coupling efficiency of a tiled coherent-beam combining system. The Zernike polynomial is used to quantify the aberration of the lens, and Fresnel diffraction is applied to numerically simulate the change in the peak light intensity when combined at a distance. The results of this paper will be useful for quantitative prediction of the beam-combining efficiency that is degraded by aberration of the lens, and it is expected to be helpful for the optimal design of a practical tiled coherent beam-combining system.