엔트로피에 의한 공동주택의 급수사용량에 관한 연구

안창환,공성훈,김종영 한국주거학회 2000 한국주거학회 논문집 Vol.11 No.3

The purpose of this study was to analyze water consumption in each apartment buildings influenced by several factors that are the income level of inhabitants, life style, the area apartments and climate. The automation of sanitary machines or facilities in recently built apartments has caused largely increases in amount of water consumption. Therefore, the design for water supply is very important for the maintenance of the optimum level or pressure of water supply. This study is based on the offer of basic data for improving the quality of water supply and employing the sanitary machines or sanitary facilities by analysis of amount increased of water consumption rapidly. Amount of water consumption data, the change in quality of entropy to the supply water pipe was analyzed and presented to indicate the necessary to basic materials for the design of an optimal water pipe.

Design of T-S Fuzzy Model based Adaptive Fuzzy Observer and Controller

안창환 한국조명.전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.11

This paper proposes the alternative observer and controller design scheme based on T-S fuzzy model. Nonlinear systems are represented by fuzzy models since fuzzy logic systems are universal approximators. In order to estimate the unmeasurable states of a given unknown nonlinear system, T-S fuzzy modeling method is applied to get the dynamics of an observation system. T-S fuzzy system uses the linear combination of the input state variables and the modeling applications of them to various kinds of nonlinear systems can be found. The proposed indirect adaptive fuzzy observer based on T-S fuzzy model can cope with not only unknown states but also unknown parameters. The proposed controller is based on a simple output feedback method. Therefore, it solves the singularity problem, without any additional algorithm, which occurs in the inverse dynamics based on the feedback linearization method. The adaptive fuzzy scheme estimates the parameters and the feedback gain comprising the fuzzy model representing the observation system. In the process of deriving adaptive law, the Lyapunov theory and Lipchitz condition are used. To show the performance of the proposed observer and controller, they are applied to an inverted pendulum on a cart.

엔트로피에 의한 수직급수관로 해석에 관한 연구

안창환,공성훈 대한건축학회 1999 대한건축학회논문집 Vol.15 No.6

The water supply system supplies very necessary water to human Iife. The reason is that recently the importance of water supply system has increased due to environmental pollution. This thesis interpreters entropy as water flow to supply water pipes for maintenance of optimal supply to the water environment. Furthermore, in this study, theoretical interpretation and an experiment were carried out in order to calculate the optimum water pressure and diameter. A vertical supply water piping system was equipped at the inside of a laboratory for the with a laboratory far the purpose of this experiment Water flow rates, pressure, and velocity were measured with respect to the operation of faucets. From the measured data, the qualitative variation of entropy in the vertical supply water piping system was analyzed and also it was suggested to the basic data for the optimum design of water piping system.

π-공액계 분자의 삼중항 여기 상태에 대한 Density Functional Theory (DFT)에 기반한 계산 방법들의 비교: 시간-의존 DFT (TD-DFT), Tamm-Dancoff 근사법을 적용한 DFT (TDA-DFT), 스핀-비제한 DFT (UDFT)

안창환,김동욱 대한화학회 2019 대한화학회지 Vol.63 No.2

We compared methodologies based on the density functional theory (DFT), e.g., time-dependent DFT (TD-DFT), TD-DFT within Tamm-Dancoff approximation (TDA-DFT), and spin-unrestricted DFT (UDFT), that are usually employed to optimize the geometries of π-conjugated molecules in their lowest lying triplet excited (T1) state. As a model system for π-conjugated molecules, we employed 1,2,3,4,5-pentacyano-6-phenyl-benzene. In conjunction with 6-31G(d) basis sets, we made use of gap-tuned range-separated ωB97X functional which is often employed recently in the calculations of molecular excited states. Near the equilibrium geometries, we found that the important difference between the geometries derived at UDFT level and those at TD-DFT or TDA-DFT methods: more stable ground-state energies but higher triplet excitation energies for UDFT derived geometries. In the studies, we discuss such differences in more detail. π-공액계 분자에 대해, density functional theory (DFT) 방법에 기반한 일반적인 삼중항 구조 최적화 방법들, 즉, 시간 의 존적 DFT (TD-DFT), Tamm-Dancoff 근사법에 기반한 TD-DFT (TDA-DFT), 그리고 스핀-비제한 DFT (UDFT)에 대한 점검을 수 행하였다. 모델 분자로서 1,2,3,4,5-pentacyano-6-phenyl-benzene가 이용되었고, 6-31G(d) 기저 함수와 더불어 여기 상태 계산에 최 근 자주 사용되는 에너지 차 조정 영역 분리 functional인 ωB97X functional이 사용되었다. 계산 결과 평형 구조 근처에서, UDFT 최적화된 구조는 TD-DFT 및 TDA-DFT 계산 구조와는 다른 차이점을 보인다. 즉, 보다 안정한 바닥 상태 에너지와 보다 높은 삼 중항 여기 에너지가 UDFT 최적화 구조에서 보인다. 본 논문에서는 이러한 차이에 대해 보다 자세히 토의된다.

Calcium homeostasis in diabetes mellitus

안창환,강지훈,정의배 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.3

Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

직류전원시스템에서 발생하는 아크사고 검출기법에 대한 연구

안창환 대한전자공학회 2022 전자공학회논문지 Vol.59 No.4

본 논문은 직류전원시스템에서 발생하는 아크사고를 검출하는 기법을 제안하고 이에 대한 실증 실험을 수행하였다. 기존의 아크사고 검출법은 퓨리에변환을 통하여 주파수영역에서 전력스펙트럼 밀도를 이용하여 분석하는 방법이 주로 사용 되지만 신뢰성이 낮은 문제가 있다. 아크사고 검출률을 향상시키기 위한 방법으로 아크사고에 적합한 주파수 대역과 아크사고 선정에 필요한 기준치를 전력스펙트럼 밀도의 평균값을 선정한다. 아크사고에 적합한 주파수 대역은 10kHz~100kHz이며, 보정법을 이용하여 핑크노이즈를 제거하여 전력스펙트럼 밀도의 평균값을 구한다. 마지막으로 아크사고 검출의 신뢰성을 증가시키기 위해서 주파수 대역에서 특정 주파수 구간을 나눠 구간별 전력스펙트럼밀도의 평균값을 이용하는 주파수분할법을 제안하였다. 주파수분할법에 대한 검출률을 확인하기 위해서 모의 직류아크사고 실험계를 구성하였다. 실험 결과 주파수 분할법을 이용한 아크사고 검출률이 전력스펙트럼밀도를 이용한 아크사고 검출률보다 약 40% 이상 높게 나타났다. 주파수분할법을 이용한 아크사고 검출방법은 태양광발전소를 포함한 직류전원시스템에 활용될 것으로 예상된다.

손실 매질에 위치한 도체의 입력임피던스 수치계산

안창환,Ahn, Chang-Hwan 대한전자공학회 2013 전자공학회논문지 Vol.49 No.11

This paper presents the numerical calculation for input impedance of a conductor located in the loss media by using the program with MATLAB. The input impedances of the conductor were numerically calculated with the moment of method. To increase an accuracy of results, the Galerkin's method which both the basic function and the weight function are the triangle function was applied. And by applying the modified image method, image sources of the conductor located in air were considered. According to the comparison between the current distributions at the conductor which were calculated with the MATLAB program and the NEC program, the reliability of the self-made program with MATLAB was obtained. In case of the conductor located in soil, which length are 1 m and 2 m, the input impedance were simulated as a function of both a conductivity and a frequency. Finally, input impedances and phases of the conductor located in soil were measured, and those results were compared with simulated results which calculated under the same conditions. 본 논문은 대표적인 손실 매질인 대지에 위치한 도체의 입력임피던스를 MATLAB을 이용한 자체 프로그램을 활용하여 계산하고, 그 결과를 나타내었다. 도체의 입력임피던스는 안테나 이론의 전자계 모델에서 유도된 포클링턴방정식에 모멘트법이 적용되어 계산되었다. 결과의 정확도를 높이기 위해서 기저함수와 가중함수가 삼각함수인 켈러킨법을 적용하였다. 대지에 위치한 도체의 영상분은 수정된 영상법을 적용하여 고려하였다. 도체의 전류분포에 대한 자체 제작한 프로그램 결과와 NEC 프로그램의 결과를 비교하여 프로그램의 신뢰성을 확인하였다. 대지에 위치한 도체의 길이가 1 m, 2 m인 경우에 도전율에 따른 임피던스를 주파수에 따라 시뮬레이션 하였다. 실제 대지에 설치된 도체의 입력임피던스와 위상을 측정하고 동일한 조건에서의 시뮬레이션 결과와 비교하였다.

엔트로피에 의한 수평급수관로 해석에 관한 연구

안창환,공성훈 대한건축학회 1999 대한건축학회논문집 Vol.15 No.3

Water is very useful to human life, and the importance of water supply system has been increased due to the environmental pollution This study defines the entropy as one of variable water flow rates on the horizontal water supply piping system in oiler to provide the satisfactory water supply system. Furthermore, in this study, theoretical interpretation and an experiment were carried out in order to calculate the optimum water pressure and diameter. A horizontal supply water piping system was equipped at the inside of a laboratory for the with a laboratory for the purpose of this experiment. Water flow rates, pressure, and velocity were measured with respect to the operation of faucets. From the measured data, the qualitative variation of entropy m the horizontal supply water piping system was analyzed and also it was suggested to the basic data for the optimum design of water piping system

초고압 전력기기의 부분방전 인공지능 인식 알고리즘 적용 연구

안창환 한국조명.전기설비학회 2019 조명·전기설비학회논문지 Vol.33 No.4

In this study, a study was conducted to improve the defect recognition rate by converting the PRPS Raw-Data acquired in the event of partial discharge of high voltage power equipment into PRPD type and using the extracted parameter as input data of artificial intelligence algorithm. As a result, it was confirmed that sufficient recognition rate was obtained to accurately recognize the type of defect compared to the conventional partial discharge recognition method using the input image. Since it is much more advantageous in terms of computational speed than image recognition method, it is reasonable to use artificial intelligence algorithm method using parameter as a way to process vast signals generated in the field. There is no authorized regulation on the recognition rate of partial discharge measurements. The only recognition rate presented by the Korea Electric Power Corporation purchase specification is 90%. Considering this, the recognition rate obtained in this study is more than 99%, which shows that the learning speed and recognition rate are improved compared to the existing method.

공동주택에서 엔트로피에 의한 급수량에 관한 조사연구

안창환 대한기계설비건설협회 1999 기계설비 Vol.111 No.-