• 지구물리
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• 제2권1호
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• pp.57-64
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• 1999

지표 부근의 수직변위 단층을 굴절파 자료로부터 신속하게 인지하기 위한 효과적 방법을 모색하기 위하여, 컴퓨터 모델링을 통하여 GRM 해석법의 특성을 분석하였다. 속도분석 함수가 수진점 사이 거리인 XY값에 따라 단층 부근에서 형태가 변하는 특성을 이용하여, XY값이 적정값보다 큰 경우와 작은 경우의 속도분석 함수값의 차이를 수평 1차 미분하여 구한 함수를 구하였으며 ''구배변화 지시자''로 명명하였다. 굴절면 경사가 작을수록, XY값의 차이가 클수록 구배변화 지시자의 최대치 진폭이 증가하고 진동거리가 짧아져 단층의 위치를 정확하게 지시하는 것으로 분석된다. 이러한 특성을 갖는 구배변화 지시자는 굴절법으로 얻어진 탄성파 자료를 이용하여 지표 근처의 고경사 단층 위치 및 분포 상태를 파악하는데 효과적으로 사용될 수 있을 것으로 기대된다.

• 한국측량학회지
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• 제25권1호
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• pp.47-53
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• 2007

인공위성 영상을 이용하여 한반도 전역과 같이 넓은 지역에 대한 효율적인 영상 판독 및 분석 작업을 수행하기 위해서는 영상모자이크 작업이 필수적으로 요구된다. 본 논문은 영상모자이크 작업시 요구되는 접합선의 자동추출 기법과 이를 기반으로 한 자동 모자이크 영상제작 방법을 제시하였다. 인위적인 불연속을 최소화하는 접합선의 자동 추출기법으로는 검색영역에 대한 제약조건을 고려한 Minimum Absolute Gray Difference Sum 알고리즘과 Canny 에지검출 알고리즘을 함께 적용하였다. 또한 획득시기가 다른 인접영상간의 밝기 차이를 균일하게 유지시키기 위한 히스토그램 매칭 방법으로는 Match Cumulative Frequency 방법을 적용하였다. 본 연구의 결과 에지검출 기법을 통해 도로나 강 등과 같은 선형특성 지형 지물을 접합선으로 선정함으로서 인접영상간의 인위적인 불연속 형성을 최소화 할 수 있었다.

• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.79-90
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• 2023

Leadership development corresponds to the focus on the individual's success and competitiveness strategy. This is the optimal direction of the organization of attitude development because it covers two aspects of the student's personality development, professionally-oriented and self-centric. The aim of the study is to identify and compare the leadership level in second-and fourth-year students to see dynamics of development and implementation of the leadership phenomenon in the professional and personal making up of future specialists. Based on the theoretical analysis of the issue, the authors developed an objective and subjective diagnostic model for leadership skills. In this study, data of the objective diagnostic technique are the key. Subjective diagnostic technique for leadership skills provides insights for problem interpretation. At the level of the first group of respondents, the average Leadership Skills Level of the second-year students was quite low and was found within the medium level. The second group of respondents consisting of the fourth-year students showed a slight but effective improvement. The Leadership Skills of this group were found at a sufficient level. Positive dynamics was revealed for all criteria of leadership skills as a result of applying objective diagnostic methods: decreased percentage of students with negative and relatively low markers of Leadership Skills Level and corresponding increase in percentage of applicants with positive markers of Leadership Skills Level. Further research can be organized in the direction of identifying and developing successful universal and professionally-oriented tactics for leadership development in students as part of attitude development.

• 한국인터넷방송통신학회논문지
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• 제24권2호
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• pp.177-184
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• 2024

데이터가 빠른 속도로 증가하고 있는 가운데 가능한 최고의 정확도를 달성하기 위해 모든 종류의 복잡한 앙상블 및 딥 러닝 알고리즘이 사용되고 있다. 그렇지만, 이러한 모델이 알 수 없는 데이터를 예측/분류/인식/추적하는 방법과 관련하여 예측, 분류, 인식, 추적이 항상 신뢰할 수 있는 것은 아니다. 데이터 부족, 불균형 데이터 세트, 편향된 데이터 세트 등과 같은 다양한 이유가 학습 모델에 의해 포착되는 결정에 영향을 미칠 수 있다. 이와 관련하여 현재 모델의 설명 가능성에 관한 연구가 관심을 끌고 있다. 현재 설명 가능성 기법과 관련하여 LIME과 SHAP가 보편적으로 사용되고 있지만, 출력 결과들은 다소 상이한 측면을 나타내고 있다. 이에 본 연구에서는 LIME과 SHAP을 결합하는 방식을 소개하고, 데모와 관련해서 IEEE CIS 데이터 세트에서 거래를 사기로 분류할 때 LightGBM 및 Keras 모델이 내린 결정에 대한 설명 가능성을 분석한다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2002년도 창립 20주년기념 국제학술대회
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• pp.67-75
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• 2002

수치항공사진측량법은 지속적인 컴퓨터공학의 발전으로 인해 측량분야에 있어 발전적인 방법중의 하나로 대두되었다. 현재의 수치항공사진측량은 많은 측정장비와 검사법을 활용할 수 있다는 장점을 지니고 있다. 하지만 자동화의 측면에서 볼 때 완전히 개발된 상태라고 할 수는 없다. 기존의 항공사진측량 순서에 따른 작업흐름은 지상기준점 측량, 판독 및 지적정보취득 등 외업의 작업량에 따라 지연되어진다. 이에 공정의 간소화를 연구함으로서 수치도화법 경제적 활용가능성을 타진할 수 있다. 이에 본 연구는 새로운 작업흐름 개발과 알고리즘 연구에 초점을 두었다. 본 연구결과 경제적인 비용절감과 지형 및 지적도 제작의 기술증진에 의 효과를 얻을 수 있다.

• 한국통신학회논문지
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• 제29권8C호
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• pp.1086-1103
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• 2004

Most research efforts on the OCDMA technology assume single-bit-per-symbol transmission techniques such as on-off keying. However, achieving high spectral efficiency with such transmission techniques is likely to be a challenging task due to the "unipolar" nature of optical signals. In this paper, an M-ary transmission technique using more than two equally-weighted codes is proposed for OCDMA local area networks, and ie BER performance and spectral efficiency are analyzed. Poison frame arrival and randomly generated codes are assumed for the BER analysis, and the probability of incorrect symbol detection is analytically derived. From the approximation, it is found that there exists an optimal code weight that minimizes the BER, and its physical interpretation is drawn in an intuitive and simple statement. Under the assumption of this optimized code weight and sufficiently large code dimension, it is also shown that the spectral efficiency of OCDMA networks can be significantly improved by increasing the number (M) of symbols used. Since the cost of OCDMA transceivers is expected to increase with the code dimension, we finally provide a guideline to determine the optimal number of symbols for a given code dimension and traffic load.

• Wind and Structures
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• 제6권6호
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• pp.485-498
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• 2003

This paper presents a mechanical model of Rain-Wind Induced Vibration (RWIV) of stay cables. It is based on the physical interpretation of the phenomenon as given in Cosentino, et al. (2003, referred as Part I). The model takes into account all the main forces acting on cable, on the upper water rivulet (responsible of the excitation) and the cable-rivulet interaction. It is a simplified (cable cross-sectional and deterministic) representation of the actual (stochastic and three-dimensional) phenomenon. The cable is represented by its cross section and it is subjected to mechanical and aerodynamic (considering the rivulet influence) forces. The rivulet is supposed to oscillate along the cable circumference and it is subjected to inertial and gravity forces, pressure gradients and air-water-cable frictions. The model parameters are calibrated by fitting with experimental results. In order to validate the proposed model and its physical basis, different conditions (wind speed and direction, cable frequency, etc.) have been numerically investigated. The results, which are in very good agreement with the RWIV field observations, confirm the validity of the method and its engineering applicability (to evaluate the RWIV sensitivity of new stays or to retrofit the existing ones). Nevertheless, the practical use of the model probably requires a more accurate calibration of some parameters through new and specifically oriented wind tunnel tests.

• Asian Journal of Atmospheric Environment
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• 제8권3호
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• pp.154-161
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• 2014

The present study was undertaken to evaluate the chemical characteristics of Asian dust (hereafter called "AD") particles with the aid of the most advanced micro-PIXE (Particle-induced X-ray emission) analytical technique. To this end, size-selected particles were sampled on a rural peninsula of Korea (Byunsan, 35.37N; 126.27E) during AD and non-AD periods in 2004. The coarse particle (> $2{\mu}m$) number density during an AD event were 170 times higher than those of the non-AD counterpart. The average net-count of silica in individual particles collected on AD event was roughly 11 times higher than that of non-AD counterpart. The X-ray net-counts of trace elements (Zn, Co, Mn, and V) were also considerably high in AD relative to the non-AD day. Particle classification based on the inter ratio analysis of elemental net-count suggests that a large portion of the coarse particles collected during AD event underwent chemical transformation to a certain degree. The visual interpretation of micro-PIXE elemental maps and elemental localization data in and/or on individual AD particles clarified the internal mixture of AD particles with sea-salt and artificial metallic particles.

• 대한안전경영과학회지
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• 제15권4호
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• pp.197-207
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• 2013

OSHA(Occupational Safety and Health Act) generally regulates employer's business principles in the workplace to maintain safety environment. This act has the fundamental purpose to protect employee's safety and health in the workplace by reducing industrial accidents. Authors tried to investigate the correlation between 'occupational injuries and illnesses' and level of regulation compliance using Survey on Current Status of Occupational Safety & Health data by the various statistical methods, such as generalized regression analysis, logistic regression analysis and poison regression analysis in order to compare the results of those methods. The results have shown that the significant affecting compliance factors were different among those statistical methods. This means that specific interpretation should be considered based on each statistical method. In the future, relevant statistical technique will be developed considering the distribution type of occupational injuries.

• 비파괴검사학회지
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• 제29권6호
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• pp.591-602
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• 2009

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport theory is presented for quantitative characterization of exfoliative corrosion through deconvolution procedure using a nonlinear least-square error minimization method. It produces practical information such as location and width of planar corrosion in layered structures of aircraft, which generally cannot be detected by conventional NDE techniques such as the ultrasonic method.