• 대한전자공학회논문지
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• 제20권1호
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• pp.15-21
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• 1983

본 논문에서는 스트라입 구조형 이중 헤테로 접합 레이저 다이오드의 횡방향 도파 기구에 대한 이론적 해석이 시도되었다. 해석 과정에서 이득 및 굴절율의 공간적 변화를 주입전류의 수학적 모델로 결정하고 섭동된 파동방정식에 의한 횡방향 도파 해석을 통해 빔폭의 활성층 두께 스트라입 폭 및 캐비티 길이 의존성을 분석하였다.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.108-115
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• 2005

Maintenance and reinforcement are very important especially in the case of the hybrid structures. In this paper, we introduce the maintenance and reinforcement design method of cable dome structures. In the case of the Olympic fencing stadium structural system has the stiffness in dependence of the initial tension force. Therefore, the verification of this phenomenon is very important. The result shows that the final tension force which is measured is almost reached to the calculated aim tension force after the maintenance ana reinforcement works is confirmed.

• Journal of Biosystems Engineering
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• 제22권1호
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• pp.30-40
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• 1997

A computer vision system was built to automatically grade the leaf tobacco. A color image processing algorithm was developed to extract shape, color and texture features. An improved back propagation algorithm in an artificial neural network was applied to grade the Burley type dried leaf tobacco. The success rate of grading in three-grade classification(1, 3, 5) was higher than the rate of grading in six-grade classification(1, 2, 3, 4, 5, off), on the average success rate of both the twenty-five local pixel-set and the sixteen local pixel-set. And, the average grading success rate using both shape and color features was higher than the rate using shape, color and texture features. Thus, the texture feature obtained by the spatial gray level dependence method was found not to be important in grading leaf tobacco. Grading according to the shape, color and texture features obtained by machine vision system seemed to be inadequate for replacing manual grading of Burely type dried leaf tobacco.

• 대한의용생체공학회:의공학회지
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• 제21권2호
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• pp.137-144
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• 2000

Clustered microcalcifications in X-ray mammograms are an important sign for the diagnosis of breast cancer. A shape-based method, which is based on the morphological features of clustered microcalcifications, is proposed for classifying clustered microcalcifications into benign or malignant categories. To verify the effectiveness of the proposed shape features, clinical mammograms were used to compare the classification performance of the proposed shape features with those of conventional textural features, such as the spatial gray-leve dependence method and the wavelet-based method. Image features extracted from these methods were used as inputs to a three-layer backpropagation neural network classifier. The classification performance of features extracted by each method was studied by using receiver operating-characteristics analysis. The proposed shape features were shown to be superior to the conventional textural features with respect to classification accuracy.

• Journal of Astronomy and Space Sciences
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• 제35권1호
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• pp.1-6
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• 2018

The reanalysis of the previously published abundance pattern of mild barium star HD202109 (${\zeta}$ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ionization potentials of chemical elements. Results show that three valuable correlations exist in the atmospheres of barium stars. The first is the relationship between relative abundances and second ionization potentials. The second is the age dependence of mean correlation coefficients of relative abundances vs. second ionization potentials, and the third one is the changes in correlation coefficients of relative abundances vs. second ionization potentials as a function of stellar spatial velocities and overabundances of s-process elements. These findings demonstrate the possibility of hydrogen and helium accretion from the interstellar medium on the atmospheres of barium stars.

• World Technopolis Review
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• 제3권2호
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• pp.66-77
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• 2014

This paper aims at exploring a conceptual framework of analyzing the evolutionary processes of regional economies by reconciling the notion of regional resilience and the concepts prevailing in the disciplines of evolutionary economics and geography. The resilience framework appears to offer a promising outlet with which combination of the seemingly contradictory conceptions is made possible. It can address why some regions manage to adapt to external shocks, renew themselves, or lock out themselves, while others are more locked in decline. In addition, it can also explain how the spatial organization of economic production, distribution, and consumption is transformed over time. Then, regional economic resilience, together with its accompanying vehicle of panarchy, emerges as a workable framework of explaining regional differentiation in regional economic performance and trajectories. Despite the risk of being a fuzzy concept, the resilience conception can be properly operationalized to provide policy principles of regional economic innovation adjusted to region-specific contexts.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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• pp.217-222
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• 2004

This paper focuses on lossy medical image compression methods for medical images that operate on two-dimensional(2D) integer wavelet transform. We offer an application of the Set Partitioning in Hierarchical Trees(SPIHT) algorithm to medical images, using a 2D wavelet decomposition and a 2D spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method, where careful scaling and truncations keep the integer precision small and the transform unitary. We have tested our encoder on medical images using different integer filters. Results show that our algorithm with certain filters performs as well and is sometimes better lossy coding using 2D integer wavelet transforms on medical images.

• Journal of Communications and Networks
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• 제4권3호
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• pp.176-188
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• 2002

This paper presents results of continuous wave and swept frequency response measurements over the frequency range of UNII lower and middle bands from 5.15GHz to 5.35GHz in indoor environments. From the continuous wave measurements at 5.2GHz, the excess path loss, and the statistical characteristics of the temporal and spatial fading were found. By sweeping the frequency over the band, envelope correlation as a function of frequency was found and the coherence bandwidth (CBW) was determined from the envelope correlation. Using a channel model, the CBW was used to evaluate RMS delay spread. The dependence of CBW on the antenna polarization was simulated and compared with the measurement results. The influence of room size and separation of transmitter and receiver for LOS paths on RMS delay spread was discussed.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.30-36
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• 2000

In this paper, a method based on the Genetic Algorithm(GA) for phase optimization is proposed. The programmable hybrid optical interconnection system implemented by the spatial light modula-tor is tested for a near-real-time optical processing. Designed diffractive grating has a 74.7[%] high diffraction efficiency and a $1.73 {\times}10^{-1}$ uniformity quantitatively. The dependence of characteris-tics on several parameters in the grating design are analyzed. Also, as a result of the geometrical transformation to obtain quantitative data for $3 {\times} 3$ spot beams, an objective optical experiment using CCD array detector produces the mean of beam intensity as a gray level of 202, the maximum value is 225, the minimum value is 186, and uniformity is quantitatively $1.93 {\times} 10^{-1}$, similar to the simulation result.

• 한국방사선학회논문지
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• 제1권3호
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• pp.17-21
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• 2007

We describe recent observations and measurements realized with microdot (MDOT) detectors having 50 mm, 100 mm, and 200 mm pitches for 3.7 keV X-rays. A gas gain of $3.1{\times}10^3$ has been measured with 50 mm pitch MDOT at potential difference much lower than those usually obtained with MSGCs. The defocusing effect caused by the existence of the readout lines passing below the insulator layer has been investigated from the drift voltage dependence of the count rate variation and the electric field simulation for all the detectors. Results concerning the spatial resolutions are presented with collimated X-ray beams.