• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.66-69
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• 2003

This paper considers a reinforcement learning(RL) which deals with real environments. Most reinforcement learning studies have been made by simulations because real-environment learning requires large computational cost and much time. Furthermore, it is more difficult to acquire many rewards efficiently in real environments than in virtual ones. The most important requirement to make real-environment learning successful is the appropriate construction of the state space. In this paper, to begin with, I show the basic overview of the reinforcement learning under real environments. Next, 1 introduce a state-space construction method under real environmental which is State Partition Method. Finally I apply this method to a robot navigation problem and compare it with conventional methods.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권1호
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• pp.77-84
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• 2007

In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the $5^{th}$-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.6-11
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• 2014

Repetitive control is a specialized control scheme to track and/or attenuate a periodic reference trajectory and/or disturbance. Most researches about repetitive control have been performed in the frequency domain. Recently, several approaches to deal with repetitive control systems in the state space are developed by representing a q filter as a state-space equation. This paper presents a design method of a repetitive control system in the state space to satisfy $H_{\infty}$ performance. The overall system is composed of a plant, a repetitive controller, and a state-feedback controller, which can be converted to a standard form used in $H_{\infty}$ control. A LMI (Linear Matrix Inequality)-based stability condition is derived for fixed state-feedback gains. Under a given q filter, another LMI condition is derived to improve $H_{\infty}$ performance and is employed to find state-feedback gains by solving an optimization problem. Finally, to verify the feasibility of the proposed method, a numerical example is demonstrated.

• 한국멀티미디어학회논문지
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• 제3권1호
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• pp.77-90
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• 2000

실시간 검증은 명세와 요구사항과의 논리적 정확성 뿐만 아니라 시간적 정확성을 확인하는 일련의 과정이다. 하지만 시간의 무한성에 의해 시스템 상태가 무한히 증가할 수 있는 상태 폭발 문제가 검증과정에서 중요한 문제점이 되고 있다. 본 논문에서는 형식 검증에 기반을 두며, 시스템의 행위 측면을 시간 오토마타로 기술한 시스템 모델이 Timed mu-calculus로 표현된 시스템의 특성에 만족하는지의 여부를 통해 명세의 완전성을 확인하는 실시간 검증 비법을 기술한다. 이를 위해 초기상태의 논리값에 초점을 두어 검증과정에서 필요로 하는 노드로만 Product Graph를 구성하여 노드 값을 결정해나가는 지역모형검사 기법에 대해 제안한다. 이 방법은 모델의 모든 상태를 조사하지 않으므로 상태 폭발 문제를 최소화 시킬 수 있어 실시간 시스템 검증에 효과적으로 적용이 가능하다.

• Structural Engineering and Mechanics
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• 제34권6호
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• pp.739-753
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• 2010

Pointing to the design requirement of prestressed space grid structure being the target cable force, the pretension scheme decision analysis method is studied when there's great difference between structural actual state and the analytical model. Based on recursive formulation of cable forces, the simulative recursive system for pretension process is established from the systematic viewpoint, including four kinds of parameters, i.e., system initial value (structural initial state), system input value (tensioning control force scheme), system state parameters (influence matrix of cable forces), system output value (pretension accomplishment). The system controllability depends on the system state parameters. Based on cable force observation values, the influence matrix for system state parameters can be calculated, making the system controllable. Next, the pretension scheme decision method based on cable force observation values can be formed on the basis of iterative calculation for recursive system. In this way, the tensioning control force scheme that can meet the design requirement when next cyclic supplemental tension finished is obtained. Engineering example analysis results show that the proposed method in this paper can reduce a lot of cyclic tensioning work and meanwhile the design requirement can be met.

• Journal of Computing Science and Engineering
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• 제9권1호
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• pp.9-19
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• 2015

The most important challenge in the region-based abstraction method as an approach to compute the state space of time Petri Nets (TPNs) for model checking is that the method results in a huge number of regions, causing a state explosion problem. Thus, region-based abstraction methods are not appropriate for use in developing practical tools. To address this limitation, this paper applies a modification to the basic region abstraction method to be used specially for computing the state space of TPN models, so that the number of regions becomes smaller than that of the situations in which the current methods are applied. The proposed approach is based on the special features of TPN that helps us to construct suitable and small region graphs that preserve the time properties of TPN. To achieve this, we use TPN-TCTL as a timed extension of CTL for specifying a subset of properties in TPN models. Then, for model checking TPN-TCTL properties on TPN models, CTL model checking is used on TPN models by translating TPN-TCTL to the equivalent CTL. Finally, we compare our proposed method with the current region-based abstraction methods proposed for TPN models in terms of the size of the resulting region graph.

• 한국정보처리학회논문지
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• 제5권8호
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• pp.2091-2101
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• 1998

상호운용성은 정보기술 및 통신분야에서 가장 중요한 요소의 하나이다. 본 논문에서는 상호운용성에 관한 시험방법 및 시험 스위트의 생산에 대하여 논의하고 있다. 적합성시험을 비롯하여 정형적인 검즈에서 가장 먼저 고려되는 치명적인 문제점은 상태공간의 폭발에 관한 사항이며 이는 상호운용성의 시험방법 및 시험 스위트의 개발에 있어서도 가장 먼저 해결되어야 할 문제이다. 본 논문에서는 페트리네트를 이용한 상운용성 시험을 지원하기 위해 새로운 상태 공간 축약 방법을 제시하며 이를 이용한 상호운용성의 시험방법 및 시험 스위트 생성 방안을 IOSM, Quasi stable state 등을 이용하여 HOSS에 기반한 상태축약 결과를 보임으로써 상호운용성시험을 효율적으로 지원하는 방안을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.174-174
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• 2000

Q-learning, based on discrete state and action space, is a most widely used reinforcement Learning. However, this requires a lot of memory and much time for learning all actions of each state when it is applied to a real mobile robot navigation using continuous state and action space Region-based Q-learning is a reinforcement learning method that estimates action values of real state by using triangular-type action distribution model and relationship with its neighboring state which was defined and learned before. This paper proposes a new Region-based Q-learning which uses a reward assigned only when the agent reached the target, and get out of the Local optimal path with adjustment of random action rate. If this is applied to mobile robot navigation, less memory can be used and robot can move smoothly, and optimal solution can be learned fast. To show the validity of our method, computer simulations are illusrated.

• 한국주거학회논문집
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• 제15권3호
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• pp.93-99
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• 2004

This study was conducted to estimate the solar energy, as an alternative energy evaluating an effect of solar radiation on indoor space of residential building. The basic data of solar radiation which is useful for architectural design was suggested using theoretical and experimental analysis. Accordingly, this study was carried out measuring the solar energy using Explicit Method. These results were compared with the results using steady state heat transfer method. The results of this study are summarized as follows; Based on the results using Explicit Method and steady state heat transfer on the indoor space of building, it was shown that an analysis on heat transfer using Explicit Method is more sensitive to the outdoor environmental changes. The results using Explicit Method to analysis and evaluate the solar radiation should be used for residential building design.

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.67-72
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• 2007

부분 최소자승회귀, 균형 잡힌 realization, 균형 잡힌 truncation을 결합함으로써, MIMO 상태공간 모델의 모델인식을 위한 효과적인 방법이 개발되었다. 개발된 방법에서 MIMO 시스템은 고차 ARX 모델로 표현되는 다중 MISO 시스템으로 분해된다. 이 때, ARX 모델의 파라미터는 부분 최소자승회귀에 의해 추정된다. 그 후, realization을 통해 각각의 MISO ARX 전달함수에 대한 MISO 상태공간 모델이 만들어지며, MIMO 상태공간 모델로 결합된다. 최종적으로, 균형 잡힌 realization과 균형 잡힌 truncation을 통해 최소의 균형 잡힌 MIMO 상태공간 모델이 얻어진다. 제안된 방법은 고압 $CO_2$ 용해도 측정 실험 장치의 온도제어를 위한 모델 예측 제어의 설계에 적용되었다.