• 한국지능시스템학회논문지
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• 제19권6호
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• pp.840-847
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• 2009

This paper deals with an $H_{\infty}$ output feedback controller design for uncertain singularly perturbed T-S fuzzy systems. Integral quadratic constraints are used to describe various kinds of uncertainties of the plant. It is shown that the $H_{\infty}$ norm of the uncertain singularly perturbed fuzzy system is less than $\gamma$ for a sufficiently small $\varepsilon$ > 0 if the $H_{\infty}$ norms of both the slow and fast subsystem are less than $\gamma$. Using this fact, we develop a linear matrix inequality based design method which is independent of the singular perturbation parameter $\varepsilon$. A numerical example is provided to demonstrate the efficacy of the proposed design method.

• 적정기술학회지
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• 제7권2호
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• pp.211-215
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• 2021

AIDS 환자는 전 세계에 4,000만 명인 것으로 추산되며, 주로 개발도상국에서 대부분의 환자가 발생하고 있다. AIDS의 원인 바이러스인 HIV는 혈중의 CD4+ T 세포에 감염되어 수개월 내지 10년 간의 잠복기간을 거치면서 CD4+ T 세포를 점점 파괴하여 환자의 면역기능을 저하시킨다. 이렇게 면역력이 약화된 AIDS 환자는 다양한 병증에 의해 사망에 이르게 된다. 현재의 CD4+ T 세포 수를 계측하는 방법은 통상 유세포분석(flow cytometry) 방법에 의해 시행되고 있다. 유세포분석 방법은 정확도가 높다는 장점이 있으나 숙련된 전문 인력이 필요하고 장비가 고가이기때문에 개발도상국에서는 이용하기 어렵다. 본 연구결과로 마이크로 여과기를 통해 소량인 5 ㎕ 혈액으로부터 백혈구를 포획하고 포획된 세포에서 CD4+ T 세포 및 CD8+ T 세포를 분석하여 AIDS를 검사하는 장비를 개발하였다. 현재의 검사 장비보다 저렴하고 고도의 기술이 필요하지 않으며 휴대가 간편한 획기적인 AIDS 검사 장비임을 시사한다.

• 한국정보시스템학회지:정보시스템연구
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• 제19권1호
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• pp.1-17
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• 2010

This paper proposes an updating policy of indoor moving object databases (IMODB) for location-based services. our method applies the Ka1man filter on the recently collected measured positions to estimate the moving object's position and velocity at the moment of the most recent measurement, and extrapolate the current position with the estimated position and velocity. If the distance between the extrapolated current position and the measured current position is within the threshold, in other words if they are close then we skip updating the IMODB. When the IMODB needs to know the moving object's position at a certain moment T, it applies the Kalman filter on the series of the measurements received before T and extrapolates the position at T with the estimations obtained by the Kalman filter. In order to verify the efficiency of our updating method, we performed the experiments of applying our method on the series of measured positions obtained by applying the fingerprinting indoor positioning method while we are actually walking through the test bed. In the analysis of the test results, we estimated the communication saving rate of our method and the error increment rate caused by the communication saving.

• 동력기계공학회지
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• 제11권3호
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• pp.35-40
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• 2007

Leak would happen because of the damage of high temperature and high-pressure valve in nuclear power plant. condition based prevention maintenance is essential by using the suitable method based on local condition. Energy loss prevention can prevent from an accurate test, Local actually and ability. The methods of test for high energy fluid leak at present are analysis of ${\Delta}T$, AE(Acoustic Emission) analysis, and thermal image. The result for test of secondary system in nuclear power plant Unit reveals that the AE occurred clearly in leakage situation, but thermal image didn't occur. It is identified that leak is occurred when the orifice located front and back of valve operates. It shows that making a impatient judgment by using the single method if it is leakage is containing uncertainty. So we think that using the Multi-Measuring method is more sound judgment than single-measuring method.

• 지반과기술
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• 제4권4호
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• pp.70-77
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• 2007

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.36.3-37
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• 2009

This is an attempt to improve a formula to predict variations of geomagnetic storm indices (Dst) from solar wind parameters. A formula which is most widely accepted was given by Burton et al. (1975) over 30 years ago. Their formula is: dDst*/dt = Q(t) - Dst*(t)/$\tau$, where Q(t) is the Dst injection rate given by the convolution of dawn-to-dusk electric field generated by southward solar wind magnetic field and some response function. However, they did not clearly specify the response function. As a result, misunderstanding seems to be prevailing that the injection rate is proportional to the dawn-to-dusk electric field. In this study we tried to determine the response function by examining 12 intense geomagnetic storms with minimum Dst < -200 nT for which solar wind data are available. The method is as follows. First we assume the form of response function that is specified by several time constants, so that we can calculate the injection rate Q1(t) from the solar wind data. On the other hand, Burton et al. expression provide the observed injection rate Q2(t) = dDst*/dt + Dst*(t)/$\tau$. Thus, it is possible to determine the time constants of response function by a least-squares method to minimize the difference between Q1(t) and Q2(t). We have found this simple method successful enough to reproduce the observed Dst variations from the corresponding solar wind data. The present result provides a scheme to predict the development of Dst 30 minutes to 1 hour in advance by using the real time solar wind data from the ACE spacecraft.

• 한국지능시스템학회논문지
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• 제14권3호
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• pp.316-323
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• 2004

이 논문에서는 특이섭동 T-S 퍼지시스템의 $H_{\infty}$ 출력 궤환 제어기의 설계를 취급한다. 특이섭동 시스템에서 저속 부시스템과 고속 부시스템의 $H_{\infty}$ 노옴이 각각 ${\gamma}$ 보다 적다면 충분히 적은 ${\varepsilon}$>0에 대해서 특이섭동 퍼지시스템의 $H_{\infty}$ 노옴이 ${\gamma}$보다 적음을 증명한다. 이러한 사실을 이용하여 특이섭동 파라메터 ${\varepsilon}$과 무관한 선형 행렬부등식을 기반으로하는 제어기 설계법을 제시한다. 제시된 설계법의 효용성을 입증하기 위하여 수치예를 보여준다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.86.1-86
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• 1998

• 지역사회간호학회지
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• 제18권2호
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• pp.310-319
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• 2007

Purpose: This study intends to investigate gender role identity and egalitarianism consciousness among adolescents and to determine the relationship between the two factors. Method: Data were collected from 376 middle and high school students in U City. Tools used were the Korean Sexual Role Identity (Kim, J. H., 2005) and the Gender Egalitarianism Consciousness among Adolescents (Kim, 2002). Data were analyzed using SPSS 12.0 for t-test, one-way ANOVA and Pearson correlation coefficient. Results: There was no significant difference between boys and girls in sender role identity. Boys' gender role identity was different according to school grade (t=-3.19, p= .00), frequency of mother's hugging (t=-2.28, p= .02) and girls' according to religion (t=-2.24, p= .03) mother's job (F=3.59, p= .02), father's education level (F=3.20, p= .04), mother's education level (F=3.24, p= .04), family harmony (F=7.28, p= .00), and frequency of mother's hugging (t=-2.41. p= .02). There was significant difference in egalitarianism consciousness according to sender (t=-12.70. p= .00) Boys' egalitarianism consciousness was different according to school type (t= .02, p= .00) and father's education level (F=4.97, p= .02), and girls' according to school grade (t=-4.21 p= .00), school type (t=-3.12, p= .00), father's level of education (F=3.78. p= .02), decision maker of important domestic matter (F=4.95, p= .00) and frequency of mother's hugging (t=2.53, p= .01). In Girls, sexual role identity and sender egalitarianism consciousness were significantly correlated with each other (r= .01, p= .04). Conclusion: Through the study, it was found that boys' concern for sexual equality of was remarkably lower than girls. Therefore, it is necessary to offer curriculums for boys and to start social education for parents.

• 한국통신학회논문지
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• 제29권7A호
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• pp.786-793
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• 2004

cdma2000 IxEV-DO 네트워크의 역방향 링크에서와 같은 자율적 전송률 제어 (ARC, Autonomous data Rate Control) 구조는 다중 QoS 환경에서의 다양한 QoS 보장 및 RoT (Rise over Thermal) 제약 조건을 만족시키지 못하는 문제가 있다. 이에 따라, 본 논문에서는 cdma2000 기반의 역방향 링크 시스템을 위한 자원 관리 기술로서, MWGF (Modified Weighted G-Fair) 스케줄러를 제안하고, 다중 QoS 서비스 환경에서 성능을 분석하였다. 제안된 스케줄러는 QoS 요구를 고려한 우선 순위를 제공할 뿐만 아니라 RoT-filling 기법을 이용해서 RoT 정규화를 보장함으로서 CDMA 시스템의 로딩 (loading)을 유지하는 구조로 설계되었다. 모의실험을 통하여, 제안된 스케줄러는 자율적 전송률 제어 구조에 비하여, 약 29 - 40 % 정도의 실시간 서비스의 전송 시간이 단축되는 것을 보였으며, 약 1.0 - 1.3 dB의 낮은 평균 수신 RoT 레벨을 유지하여 낮은 시스템 로딩을 제공함을 보였다. 이와 같은 낮은 시스템 로딩은 여분의 간섭량을 타 서비스 또는 타 셀에 제공하여 시스템 전체의 용량을 증가시킬 수 있게 된다.