• 대한전기학회논문지
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• 제35권5호
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• pp.185-192
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• 1986

This paper deals with the general mathmatical model of the CSI-fed induction motor system. The inverter is represented by a switching function matrix which is combined with the dg model of an induction motor. Complete system model is given by a set of differential equations in a closed form, which inherently includes the harmonic effects of the converter and the inverter. The model is valid in evaluating both the transient and steady state responses, while the more simple analytical model can be derived from the general model, in a steady state. With the model proposed, the digital simulation is carried out on a 10KVA CSI-induction motor system and the simulation results show good agreements with experimental ones.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.466-470
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• 1988

A tunable reduced-order distillation model is proposed for real-time applications. To develop the model, a binary distillation column with MaCabe-Thiele assumptions was considered first and then the governing equations for the column were reduced to a simplified vector differential equations using the collocation method combined with cubic spline interpolation function. The final reduced-order model has four tuning parameters, relative volatilities and liquid holdups for rectifying and stripping sections, respectively. To assess the applicability of the developed model,the real-time adjustment of the model was tried by recursively updating the tuning parameters using the BKF algorithm. As a result, it was found that the reduced-model follows the simulated distillation process very closely as the parameters are improved.

• 대한기계학회논문집A
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• 제29권5호
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• pp.734-742
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• 2005

The present study proposes the integrity evaluation model for a straight pipe with local wall thinning defect, which reflects the characteristics of training shape and loading condition in the Piping of nuclear power plant. For this purpose, a series of finite element analyses are performed under various defect geometries and loading conditions, and real pipe experiment data performed previously is employed. The model includes the effect of thinning length as well as thinning depth and width, and also it considers the combined loading effect between internal pressure and bending moment. The proposed model has been validated using the results of finite element analysis and pipe experiment data. The results indicate that the proposed model provides more reliable predictions of pipe failure than the current existing model, in terms of accuracy, consistency, and conservativeness of results.

• 대한환경공학회지
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• 제36권3호
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• pp.153-161
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• 2014

본 연구에서는 합성 항균제로 이용되는 Triclosan이 $Cu^{2+}$, $Zn^{2+}$, $Cr^{6+}$, $Cd^{2+}$, $Hg^{2+}$, $Pb^{2+}$ 등과 같은 중금속과 공존할 경우의 독성영향을 발광박테리아인 Vibrio fischeri를 이용하여 평가하였다. 우선, Triclosan과 상기 6종 중금속의 단일물질별 Vibrio fischeri에 대한 독성을 평가한 결과, $Hg^{2+}$의 독성이 가장 높았으며 뒤이어 Triclosan > $Pb^{2+}$ > $Cu^{2+}$ > $Cr^{6+}$ > $Zn^{2+}$ > $Cd^{2+}$순의 독성민감도가 나타났다. 각 물질의 독성평가결과를 바탕으로 Triclosan과 중금속 혼합물질의 독성작용분석을 위해 유사한 독성작용을 가정하여 독성치를 예측하는 Concentration Addition (CA)모델과 독립적인 독성작용을 가정하여 독성치를 예측하는 Independent Action (IA)모델에 대한 상관도분석을 실시하였다. 그 결과 Triclosan + Cu, Triclosan + Zn, Triclosan + Pb, Triclosan + Hg, Triclosan + Cd, 그리고 Triclosan + Cr 등 모든 조합에서 CA모델보다는 IA모델과 상관성이 높은 것으로 나타나 Triclosan과 대상 중금속들은 서로 독립적인 독성작용을 하는 것으로 나타났다. 한편 Triclosan과 중금속의 혼합독성영향은 IA모델로 예측된 $EC_{50mix}$기준으로 Triclosan + Cu, Triclosan + Zn, Triclosan + Pb, Triclosan + Hg, Triclosan + Cd, 그리고 Triclosan + Cr의 실측 $EC_{50mix}$이 IA모델로 예측한 농도보다 각각 191%, 226%, 138%, 137%, 209% 그리고 138%로 나타나, Triclosan과 시험 중금속이 공존하는 경우, 모두 길항작용이 나타나는 것으로 확인되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1207-1212
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• 2004

A model for the phonon dispersion relationship for cubic zinc sulfide structure, for example SiC, is developed in terms of two unknown force constants. Born model that incorporates bond bending and bond stretching, is used for the force constants. The force constants are determined by fitting to experimental data. Using only the nearest-neighbor coupling results in $6{\times}6$ sized dynamic matrix. The eigenvalues of dynamics matrix for each wavenumber in 3-D ${\kappa}$ space correspond to frequencies, 3 for optical phonon and 3 for acoustic phonon, which is so-called dispersion relation (${\kappa}$-${\omega}$). The density of state is determined by counting the states for each frequency bin, and the properties such as specific heat and thermal conductivity can be obtained. The specific heat is estimated on this model and compared with experiment and other models, i.e. Debye model, Einstein model and combined Debye-Einstein model. In spite of the simple bond potential model, reasonable agreements are found.

• Journal of Information Processing Systems
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• 제8권4호
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• pp.539-554
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• 2012

Model-driven and component-oriented development is increasingly being used in the development of embedded systems. When combined, both paradigms provide several advantages, such as higher reuse rates, and improved system quality. Performing model-driven and component-oriented development should be accompanied by a component model and a method that prescribes how the component model is used. This article provides an overview on the MARMOT method, which consists of an abstract component model and a methodology for the development of embedded systems. The paper describes a feasibility study that demonstrates MARMOT's capability to alleviate system design, verification, implementation, and reuse. Results indicate that model-driven and component-based development following the MARMOT method outperforms Agile development for embedded systems, leads to maintainable systems, and higher than normal reuse rates.

• 한국음향학회지
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• 제24권1호
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• pp.58-68
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• 2005

본 논문에서는 잡음 환경에서 강인한 음성 인식을 위하여 특징 보상 기법의 성능을 향상시킬 수 있는 방법을 제안한다. 기존의 음성 모델 기반의 특징 보상 기법에서 이용되는 오염 음성 모델 추정 방식은 입력 음성에 대한 변별력 있는 사후 확률 예측을 보장하지 못하며, 부정확하게 계산된 사후 확률은 복구된 음성에서 명료도 하락의 문제를 일으킨다. 제안하는 기법에서는 오염 음성 모델 추정 과정에 분별적 훈련 방식의 하나인 최소 분류 오류 (MCE) 훈련 기법을 도입한다. MCE 훈련 기법을 적용하기 위해 변별력 하락의 가능성을 가지는 '경쟁 요소' 를 결정하는 기법을 제안한다. 병렬결합된 혼합 모델 (PCMM) 기반의 특징 보상에 MCE 훈련 기법을 적용하는 과정을 제안하고 변별력 향상의 영향을 관찰한다. Aurora 2.0 데이터베이스와 실제 자동차 주행 환경에서 수집된 음성 데이터베이스에 대한 성능 평가를 실시한다. 실험 결과는 제안한 기법이 음성 인식 성능 향상에 도움이 되는 것을 입증한다.

• 한국해양공학회지
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• 제31권6호
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• pp.405-412
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• 2017

Because of the rapid development of computer technology in recent years, wave models can utilize parallel calculations for the high-resolution prediction of open sea and coastal areas with high accuracy. Parallel calculations also allow national agencies in the relevant sectors to produce marine forecasting data through massive parallel calculations. Meanwhile, the eastern coast of the Korean Peninsula has been increasingly damaged by swell-like high waves, and many researchers and scientists are continuing their efforts to anticipate and reduce the damage. In general, the short-term transformation of swell-like high waves can be reproduced relatively well in the third generation wave models, but the transformation of relatively long period waves needs to be simulated with higher accuracy in terms of the nonlinear wave interactions to gain a better understanding of the low-frequency wave generation and development mechanisms. In this study, we developed a calculation module to improve the calculation of the nonlinear energy transfer in the 3rd generation wave model and integrated it into the wave model to effectively consider the nonlinear wave interaction. First, the nonlinear energy transfer calculation module and third generation model were combined. Then, the combined model was used to reproduce the wave transformation due to the nonlinear interaction, and the performance of the developed operation module was verified.

• 약학회지
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• 제38권6호
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• pp.800-805
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• 1994

Antacid(AM, 600 mg/kg=aluminium hydroxide, magnesium hydroxide, and simethicone with a ratio of 1 : 1 : 0.1) and aceglutamide aluminium(AGA, 263 mg/kg)-Effect of the combined preparation containing on the gastric mucosal hexosamine, sialic acid, and aluminium contents adhered to the gastric wall of the rat was investigated. Severe ulcers were produced in rats by injecting of $30\;{\mu}l$ acetic acid(30%) into the subserosal layer of one position in the corpus. When given orally for 15 consecutive days, AM(1,200 mg/kg), AGA(525, 1,050 mg/kg), and the combined preparation significantly decreased the ulcer area. AGA(525, 1,050 mg/kg) and the combined preparation also increased the amount of hexosamine and sialic acid in the intact and ulcerated areas. On the other hand, the contents of hexosamine and sialic acid were not affected by AM (600, 1,200 mg/kg). The amount of aluminium adhered to the gastric wall of the rat was higher in the combined preparation when compared to the AM(600 mg/kg) and AGA(263 mg/kg). The aluminium contents adhered may play an important role protecting mucosa from aggresive action of gastric juice and potenting defensive factors through the increase of mucosa-forming components by AGA.

• 산업경영시스템학회지
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• 제40권3호
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• pp.92-98
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• 2017

The rapid growth of engineering technology and the emergence of systemized and large-scale engineering systems have resulted in complexity and uncertainty throughout the lifecycle activities of engineering systems. This complex and large-scale engineering system consists of numerous components, but system failure can be caused by failure of any one of a number of components. There is a real difficulty in managing such a complex and large-scale system as a part. In order to efficiently manage the system and have high reliability, it is necessary to structure a system with a complex structure as a sub-system. Also, in the case of a system in which cause of failures exist at the same time, it is required to identify the correlation of the components lifetime and utilize it for the design policy or maintenance activities of the system. Competitive risk theory has been used as a theory based on this concept. In this study, we apply the competitive risk theory to the models with combined structure of series and parallel which is the basic structure of most complex engineering systems. We construct a competing risks model and propose a mathematical model of net lifetime and crude lifetime for each cause of failure, assuming that the components consisting a parallel system are mutually dependent. In addition, based on the constructed model, the correlation of cause of failure is mathematically analyzed and the hazard function is derived by dividing into net lifetime and crude lifetime.