• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.370-375
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• 2004

This paper proposes an algorithm that estimates three dimensional array shape calibration about the bottom-mounted sensor array. under the assumption that the active sources are in the far-field with unknown positions. Under some assumptions. we calculate the sensor positions via an algebraic solutions of a least squares problem that the linear equations are related to the sensor positions and directions or arrival. We give examples of algorithm performance from both computer simulations and sea test. We also illustrate the performance of sensor positions estimation as a function of time delay estimation variance and the distribution of the localizing sources.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2407-2409
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• 2002

강화학습이란 에이전트가 알려지지 않은 미지의 환경에서 행위와 보답을 주고받으며, 임의의 상태에서 가장 적절한 행위를 학습하는 방법이다. 만약 강화학습 중에 에이전트가 과거 문제들을 해결하면서 학습한 환경에 대한 지식을 이용할 수 있는 능력이 있다면 새로운 문제를 빠르게 해결할 수 있다. 이런 문제를 풀기 위한 방법으로 에이전트가 과거에 학습한 여러 문제들에 대한 환경 지식(Domain Knowledge)을 Local state feature라는 기억공간에 학습한 후 행위함수론 학습할 때 지식을 활용하는 방법이 연구되었다. 그러나 기존의 연구들은 주로 2차원 공간에 대한 연구가 진행되어 왔다. 본 논문에서는 환경 지식을 이용한 강화학습 알고리즘을 3차원 공간에 대해서도 수행 할 수 있도록하는 개선된 알고리즘을 제안하였으며, 제안된 알고리즘의 유효성을 검증하기 위해 초소형 비행체의 항공운항 학습에 대해 모의실험을 수행하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.299-299
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• 2018

지역빈도해석은 수문관측자료의 보유기간이 짧은 지점 또는 미계측 지점에 대하여 보다 정확하며 신뢰할 수 있는 설계수문량을 산정하기 위해 널리 사용되고 있는 방법이다. 지역빈도해석에서 사용되는 가장 대표적인 모형인 홍수지수모형 (index flood model)은 각 지점의 표본평균을 홍수지수로 정의하고 이를 이용하여 설계수문량을 산정하는 방법이다. 모홍수지수모형 (population index flood model)은 표본평균을 홍수지수로 사용함으로써 발생하는 설계수문량의 왜곡과 오차를 극복하기 위해 제안된 방법으로 홍수지수를 미지의 모분포로 가정한 후 설계수문량을 산정한다. 본 연구에서는 모홍수지수모형을 국내 강우관측자료에 적용하여 지역빈도해석을 수행하고자 한다. 먼저, 이질성척도(heterogeneity)를 통해 지역동질성이 확인된 지역에 대하여 GEV 분포형을 적용한 비정상성 모홍수지수모형을 적용해 지역빈도해석을 수행하고 확률강우량을 산정하였다. 또한, 기존의 지점빈도해석 및 L-moment 기반의 지역빈도해석 결과와 비교를 통해 모홍수지수모형의 적용성을 확인하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1138-1144
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• 2011

This article deals with the problem of fault detection of a spacecraft's actuators. The authors introduce an extended unknown input observer for nonlinear systems. This is an extended form of unknown input observers which are used for linear systems. Since faults are not available, those are considered as unknown inputs. Unknown input observers can estimate states without full information of inputs if some conditions are satisfied. The authors suggest a continuous-time extended UIO (eUIO) and prove the convergence of state estimation errors. Since the dynamic equation of a spacecraft is nonlinear, an extended UIO can be applied. Three eUIOs are designed to monitor three reaction wheels. The moving averages of each eUIO's residuals are selected for decision logic. The proposed method is verified by numerical simulations.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.3
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• pp.111-123
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• 1997

In order to understand the spatial forms of stream, this study aimed to typify stream microtopography through the collection of common names of topography determined by fishermen and to describe stream landscapes by using these typology. The seventeen stream microtopography names were sorted out and divided into three types : the streamside space which includes Kaeul-jari, Hapsu-mori, Cholpyok-jidae, Kyekok-jidae and Korpuri, stream plate which includes Youl, Mulgol, So and Ungdongi, and streambed materials which includes Ampan-jidae, Pawi-jidae, Dolpat-jidae, Chagal-jidae, Chanchgal-jidae, Moraetop, Kamtang-padak and Suchodae. The spatial characteristics of stream microtopography landscape were described according to the comparison of landform, the support of fishing, accessibility, viewpoint and eye-catching degree. The tipification of stream microtopography and their symbolization will offer a rich vocabulary to describe diverse spatial forms of stream.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.113-115
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• 1997

This paper presents an efficient method which can estimate the system with unmodeled dynamics using D-L networks. The proposed method is to estimate system with unmodeled dynamics recursively from only input-output information, which can exclude additional procedure for system description and thus reduce the required computational burden for real-time estimation. Higher convergence speed is achieved with our manner when compared with widely-used conventional methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1368-1375
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• 1993

This paper deals with the decentralized robust adaptive controller design for large-scale interconnected systems. We consider an arbitrary interconnection of subsystems with unkown parameters and bounded disturbances. When the disturbance and uncertain interconnections are present, the stability of the controlled large scale system is ensured if there exists a positive definite M-matrix which is related to the bound of the interconnections. The possible bound of the interconnections is assumed to be known Pth order polynomials for the decentralized adaptive controller. A modified adaptive law is proposed guaranteeing the existence of a region of attraction from which all signals converge to a residual set Do, which contains the equilibrium.

• The Korean Journal of Applied Statistics
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• v.15 no.1
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• pp.129-137
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• 2002

This paper suggests a generalized logit model with mixed effects for analysing frequency data in multi-contingency table. In this model nominal response variable is assumed to be polychotomous. When some factors are fixed but considered as ordinal and others are random, this paper shows how to use baseline-category logits to incoporate the mixed-effects of those factors into the model. A numerical algorithm was used to estimate model parameters by using marginal log-likelihood.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.730-732
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• 2005

본 논문에서는 자율적인 다수의 에이전트들이 협력하여 미지의 공간을 탐사하는 실시간 그래프 탐색 알고리즘인 MADFS를 제안하고 그 효율성을 분석한다. 이 알고리즘은 깊이-우선 탐색(DFS)에 기초한 단일 에이전트 공간 탐사 알고리즘인 dFS-RTA* 와 DFS-PHA* 를 멀티 에이전트 환경에 적합하게 에이전트 간 정보공유 방식과 방문노드 선택전략을 설계하여 확장하였다. 본 논문에서는 대표적인 3차원 온라인 게임 환경인 Unreal Tournament 게임과 지능형 캐릭터 에이전트인 KGBot를 이용한 실험을 통해 알고리즘의 완전성과 효율성을 분석해본다.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.33 no.1
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• pp.75-82
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• 2020

Objectives : The purpose of this study is to report the effect of traditional oriental hair care products and Yukmijihwang-huan on two androgenetic alopecia patients. Methods : Two androgenetic alopecia patients were treated by traditional oriental hair care products and Yukmijihwang-huan was prescribed to all two patients. Improvements of patients were evaluated through photographs. Results : As a result of examining photographs, symptoms of alopecia in two cases were improved. Conclusions : This study shows us that traditional oriental hair care products and Yukmijihwang-huan effect on two androgenetic alopecia patients. However, prospective study with big sample size control would be required.