• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.449-451
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• 1997

In this paper, A continuous control reaching law for variable structure control is proposed to reduce the chattering and improve the robustness properties in the presence of matched uncertainly.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2000년도 제52차 추계학술대회 연제집
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• pp.199-200
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• 2000

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2000년도 제52차 추계학술대회 연제집
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• pp.201-202
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• 2000

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1998년도 제50차 추계 학술대회 연제집
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• pp.212-213
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• 1998

• 대한수학회지
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• 제46권5호
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• pp.1105-1117
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• 2009

In this paper a parameter identification problem for a damped sine-Gordon equation is studied from the theoretical and numerical perspectives. A spectral method is developed for the solution of the state and the adjoint equations. The Powell's minimization method is used for the numerical parameter identification. The necessary conditions for the optimization problem are shown to yield the bang-bang control law. Numerical results are discussed and the applicability of the necessary conditions is examined.

• International Journal of Air-Conditioning and Refrigeration
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• 제15권3호
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• pp.129-136
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• 2007

In this paper, we suggest PI control with the Smith predictive controller to improve transient response of a variable speed refrigeration system (VSRS). As the refrigeration system has long dead time inherently, it is difficult to get fast responses of super-heat and reference temperature. We incorporated the Smith predictive controller into PI to compensate the effect of the long dead time of the system. At first, we introduced the decoupling model of the system to control capacity and superheat simultaneously and independently. Next, we designed the predictive controller of the superheat based on PI control law. Finally, the control performance by the proposed method was investigated through some numerical simulations and experiments. The results of the simulations and experiments showed that the proposed PI control with the predictive controller could obtain acceptable transient behaviour for the system.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(C)
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• pp.191-194
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• 2011

문서를 이루는 단어들의 빈도수가 지수법칙(power law)를 따른다는 지프의 법칩(Zipf's law)이 있다. 이러한 단어분포를 고려하여 문서의 토픽을 찾아내는 기계학습법이 디리쉴레 프로세스(Dirichlet process) 이다. 이를 발전시켜서 데이터의 잠재 요인(latent factor)들을 베이즈 확률모델에 기반한 샘플링 바탕으로 찾는 방법이 인디언 뷔페 과정(Indian buffet process) 이다. 우리는 25가지의 특징(feature)들에 대한 점수(rating)들이 볼드(blood oxygen dependent level) 신호와 함께 주어지는 PBAIC 2007 데이터에 주성분 분석법(principal component analysis)를 적용했다. PBAIC 2007 데이터는 비디오 게임을 수행하며 기능적뇌영상(functional magnetic resonance imaging, fMRI) 촬영을 하여 얻어진 공개데이터이다. 우리의 연구에서는 주성분 분석법을 이용하여 10개의 독립 성분(independent component)들을 찾았다. 그리고 1.75초 마다 촬영된 BOLD 신호와 10개의 고유벡터(eigenvector)들간의 내적을 취하여 가중치(weight)를 구하였다. 성분들의 가중치를 낮은 순서로 정렬함으로써 각 시간마다 주도적으로 영향을 미치는 성분들을 알아낼 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.464-475
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• 2009

Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.

• 분석과학
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• 제17권1호
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• pp.23-28
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• 2004

Trace amount of uranyl (II) has been determined spectrophotometrically by measuring the optical density of the light blue yellowish coloured solutions formed by reaction between the metal ion and nicotinohydroxamic acid (NHx) in presence of different secondary ligands in strong isoamyl alcohol alkaline medium. The absorption maxima for both aqueous and extracted systems measured at their respective optimum pH were found to be 360 and 559 nm (DETA), 375 and 358 nm (EDA), 369 and 362 nm (piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 - picoline), respectively at which Beer's law was obeyed. Effect of pH, reagent concentration, order of addition of reagent, time, temperature and solvent media on the absorption spectra have also been studied. Among the different systems studied, the shortest concentration range of uranyl(II) adhering to Beer's Law was 2.4 - 10.5 ppm observed for $UO_2(II)$ - NHx - DETA system in aqueous medium and also for iso amyl alcohol(IAA) extracted $UO_2$ - NHx - pyridine system was 2.4 - 7.8.

• 한국환경보건학회지
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• 제41권1호
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• pp.11-16
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• 2015

Objectives: This study assessed the impact of the smoke-free law on secondhand smoke exposure in computer game rooms by measuring concentrations of particulate matter smaller than $2.5{\mu}m$($PM_{2.5}$). Methods: Indoor $PM_{2.5}$ concentrations were measured in 56 (during the smoke-free guidance period) and 118 computer game rooms (after the law went into effect) in four cities (Seoul, Cheonan, Daegu and Kunsan) in Korea. The number of smokers in the computer game rooms was also counted every five minutes. Results: Although a smoking ban had been implemented nationally, smoking was observed in 47% of the computer game rooms. Smoking density decreased from 1.62 persons per $100m^3$ during the guidance period to 0.32 persons per $100m^3$ after the smoke-free law. There is no statistically significant difference of $PM_{2.5}$ concentrations before and after the smoking ban. The $PM_{2.5}$ concentration was two times higher than the US NAAQS of $35{\mu}g/m^3$. The $PM_{2.5}$ concentration in computer game rooms without smokers was two times higher than the outdoor concentration. Conclusion: The smoke-free law in computer game rooms was complied with, even after the guidance period, in Korea. Indoor $PM_{2.5}$ concentration after smoke-free law implementation was high due to this non-compliance. High $PM_{2.5}$ concentration in computer game rooms without smokers might be due to smoking booths. The complete prohibition of smoking in computer game rooms should be implemented to protect patrons from secondhand smoke exposure.