• 대한수학회보
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• 제52권5호
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• pp.1495-1515
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• 2015

This paper deals with the numerical methods for the reconstruction of the source term in a linear parabolic equation from final overdetermination. We assume that the source term has the form f(x)h(t) and h(t) is given, which guarantees the uniqueness of the inverse problem of determining the source term f(x) from final overdetermination. We present the regularization methods for reconstruction of the source term in the whole real line and with Neumann boundary conditions. Moreover, we show the connection of the solutions between the problem with Neumann boundary conditions and the problem with no boundary conditions (on the whole real line) by using the extension method. Numerical experiments are done for the inverse problem with the boundary conditions.

• 한국대기환경학회지
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• 제21권5호
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• pp.495-505
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• 2005

This study is to estimate source contribution by air pollutantion types (point, area, line) over Seoul metropolitan area. The Air Pollution Model (TAPM) and the highly resolved anthropogenic and biogenic gridded emissions ($1km{\times}1km$) were applied to simulate $SO_2,\;NO_2,\;O_3\;and\;PM_{10}$ concentrations by seasons and contribution was estimated by their source types (point, area, line). The results showed that the simulated concentrations of secondary pollutant agreed well with observed values with an index of agreement (IOA) over 0.4, whereas IOAs over 0.3 were observed for most primary pollutants. The contributions of each source types by seasons were similar. The point source contribution was the highest for $SO_2$ at medium level ranged from $55.1\%\;to\;61.5\%$. But the contribution from area source during for the spring and summer increased as the concentration level increased. The line source contribution was the highest for $NO_2$ at all levels ranged from $68.3\%\;to\;93.1\%$. The results indicate that $SO_2$ emissions should be mainly controlled from point source, as well as area source at higher level concentration. Also, $NO_2\;and\;PM_{10}$ to from line source should be controlled.

• 한국지구과학회지
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• 제38권4호
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• pp.263-268
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• 2017

한 개 측선에서 얻어진 중력 변화율 텐서 자료를 이용하여 주향과 경사를 가지는 선형 이상체의 위치를 결정하는 알고리즘을 제시하였다. 기존에 연구된 중력 변화율 텐서를 이용한 선형 이상체의 주향과 경사를 결정하는 방법을 발전시켜서, 선형 이상체의 주향과 경사를 결정한 이후 이상체의 위치를 결정하는 알고리즘을 개발하였다. 선형 이상체의 주향과 경사는 2차원 이상체로부터 얻어지는 중력 변화율 텐서가 회전 변환 후 2개의 독립 성분만을 가진다는 특징을 이용하여, 중력 변화율 텐서의 5개의 독립 성분을 2개의 독립 성분으로 축소시키는 회전 변환 각으로부터 선형 이상체의 주향과 경사를 결정한다. 이상체의 위치를 가리키는 방향 벡터는 중력 변화율 텐서의 회전변환 후 남은 2개 독립 성분의 비를 이용하여 유도하였다. 여러 측점에서 계산된 이상체를 가리키는 방향 벡터가 수렴하는 영역이 선형 이상체의 위치로 결정된다. 최소자승법을 이용하여 방향 벡터의 수렴 영역을 결정하는 알고리즘을 제시하였고, 수치모델링 자료를 통하여 유용성을 검토하였다.

• Nuclear Engineering and Technology
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• 제30권6호
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• pp.485-495
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• 1998

Migration characteristics of tracers in a rock fracture in a case of line-source and line-collection was studied. The fracture plane was discretized into a square mesh to which variable apertures were assigned. The spatially varying apertures of a fracture were generated using a geostatistical method, based on a given aperture probability density distribution and a specified spatial correlation length. The flow potential and pressure at each node were computed. Calculations showed that fluid flow occurs predominantly through a few preferred paths. Hence, the large range of apertures in the fracture gives rise to flow channeling. The solute transport was calculated using a particle tracking method. The migration plumes of tracer between injection line and withdrawal line are displayed in contour plots. The elution curves are shown to be controlled by the aperture density distribution and to be insensitive to statistical realization and spatial correlation length.

• 한국환경과학회지
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• 제15권3호
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• pp.287-292
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• 2006

The purpose of this paper is to evaluate the noise level and source, reduce the subway line II noise. As a result of measurement of subway line II in Busan the highest value section of uproad line was from Jigegol to Motgol by 89 dB(A). The sections of conversation and listening interference(over 80 dB(A)) were 21 sections(55%) of 38 sections. Among these sections, 15 sections(71%) were produced rolling noise, 3 sections(14%) squeal noise, 2 sections(10%) braking noise and 1 section(5%) fan noise, and then a main noise source was the rolling noise. In case of downroad line, the highest value section was from Busan Metro Art Museum to Centum city, Motgol to Jigegol by 88 dB(A). The sections of conversation and listening interference(over 80 dB(A)) were 18 sections(47%) of 38 sections. Among these sections, 15 sections(83%) produced rolling noise, 2 sections(11%) squeal noise and 1 section(6%) braking noise were investigated in this study. and then a main noise source was the rolling noise.

• 소음진동
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• 제8권5호
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• pp.974-980
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• 1998

본 논문은 직교이방성 탄성계에서 내부 선형하중에 의한 탄성파의 거동을 고찰하였다. 첫째로, 내부 발진원에 대한 탄성과 거동식을 무한계와 반구계에서의 직교이방성 매체에서 유도하였고, 둘째로 Cargniard-DeHoop을 이용하여 순간선형하중에 대한 무한계와 반구계에서의 탄성과 거동식을 유도하였다. 반구계에서 탄성파에 대한 거동식은 무한계에서 유도한 결과와 반구의 표면에서 분산되는 반사파의 합으로 표현되고, 경계영역에서 경계조건을 만족하였다. 여러 가지 이방성 매체에 대한 수치해석 결과를 제시하였고, 이방성 매체의 특성인 bulk wave의 Lacunae 및 표면파의 영향을 고찰할 수 있었다. 본 논문의 결과는 지진연구, 복합소재 특성 연구, 지능형소재 특성연구 등에 응용될 것이다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제8권3호
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• pp.295-302
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• 2002

이 논문에서는 전자화폐 시스템 사용의 기술적인 문제점에 관한 몇가지 해결방안을 제안한다. 그 해결책은 온/오프 라인 겸용 전자화폐, 원카드, 주문형 시스템, 카드 대 카드 이체 시스템 등이다. 이 대안들이 엔젤플러스 전자화폐 사례에서 소스코드로 기술되었다. 전자화폐는 IC형과 네트워크형으로 분류 한다. 그러나 그들은 통합되어야 한다 최종사용자는 편리성을 위하여 겸용으로 사용되기를 원한다. 이 논문에서는 사례연구에 의하여 온/오프 라인 겸용 전자화폐를 개발한다. 이 논문을 바탕으로 미래연구에서는 소비자지향의 다양한 기능을 소유한 전자화폐 개발이 진행되어야 할 것이다.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1251-1264
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• 2018

The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.45-53
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• 2013

In this paper, we analyze the typical phase voltage and line current waveform characteristics of the distribution system with 3 phase small synchronous generation source in case with load and non-load group, in order to investigate the power quality for end load connected of generation source. As demonstrated by our experimental results, the distortion and power quality of phase voltage and line current waveform were relatively good for low voltage 3 phase model grids connected of 3 phase small synchronous generation source in case with non-load group. However, distortion and power quality of voltage and current waveform was poor for low voltage 3 phase model grids connected to 3 phase small synchronous generation source in the load group with some phase voltage and frequency difference. From the above results, we conclude that the phase voltage and frequency of 3 phase generation source must be identical to that of distribution system source to maximize the power quality. Also, special attention is required in case of having load group or non-load group to 3 phase generation source.

• Journal of Information Display
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• 제7권4호
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• pp.17-20
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• 2006

The inline manufacturing equipment using a combination of the belt source and LPS source which is innovatively designed is introduced for the large-size AMOLED. The features of the inline system include 60sec TACT time, 19 numbers of chambers, non-substrate bending and easy application to very thin TFT substrates for the $4^{th}$ - $8^{th}$ Generation AMOLEDs.