• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.289-304
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• 2010

This paper proposes a novel scheme for cooperative spectrum sensing on distributed cognitive radio networks. A fuzzy logic rule - based inference system is proposed to estimate the presence possibility of the licensed user's signal based on the observed energy at each cognitive radio terminal. The estimated results are aggregated to make the final sensing decision at the fusion center. Simulation results show that significant improvement of the spectrum sensing accuracy is achieved by our schemes.

• 설비공학논문집
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• 제27권5호
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• pp.233-240
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• 2015

This paper discusses compressors operating number control strategy using cooperative logic to cope with variable partial load for high efficiency of a centrifugal water chiller. The cooperative logic is composed of a speed-up and speed-down controller, enabling smooth operation of compressors and equivalent distribution of thermal load in each compressor. This centrifugal water chiller design can be operated with high efficiency without incurring excessive energy waste and large transient phenomena at partial load states. Simulations in MATLAB and experiments in a real chiller system were conducted and verified the high efficiency control of a centrifugal water chiller achieved by the suggested strategy.

• Journal of information and communication convergence engineering
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• 제14권1호
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• pp.1-8
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• 2016

Spectrum sensing in cognitive radio networks allows secondary users to sense the unused spectrum without causing interference to primary users. Cognitive radio requires more accurate sensing results from unused portions of the spectrum. Accurate spectrum sensing techniques can reduce the probability of false alarms and misdetection. In this paper, a two-stage spectrum sensing scheme is proposed for cooperative spectrum sensing in cognitive radio networks. In the first stage, spectrum sensing is executed for each secondary user using energy detection based on double adaptive thresholds to determine the spectrum condition. If the energy value lies between two thresholds, a fuzzy logic scheme is applied to determine the channel conditions more accurately. In the second stage, a fusion center combines the results of each secondary user and uses a fuzzy logic scheme for combining all decisions. The simulation results show that the proposed scheme provides increased sensing accuracy by about 20% in some cases.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.720-723
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• 1997

This paper presents a cooperative control method for multiple robots. This method is based on local sensors. The proposed method integrates all information obtained by local perception through a set of sensors and generates commands without logical conflicts in designing control logic. To control multiple robots effectively, a global control strategy is proposed. These methods are constructed by using AND/OR logic and transition firing sequences in Petri nets. To evaluate these methods, the object-searching task is introduced. This task is to search an object like a box by two robots and consists of two sub-tasks, i.e., a wall tracking task and a robot tracking task. Simulation results for the object-searching task and the wall tracking task are presented to show the effectiveness of the method.

• 한국컴퓨터정보학회논문지
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• 제27권7호
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• pp.35-48
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• 2022

본 연구에서는 멀티에이전트 환경에서 지식을 표현하고 추론함에 있어서 증명 이론적 방법을 제안한다. 이 방법은 논리적 결과를 기계적 방법으로 결정하므로 초기 인공지능 연구부터 핵심분야로 발전해 왔다. 하지만 임의의 닫힌 문장들의 집합에서 항상 명제가 증명할 수 있지 않기에 논리적 결과가 결정할 수 있어지려면 절 형식의 문장으로 그 표현 범위를 제한한다. 그리고 절 형식의 문장들에서만 적용 가능한, 단순하면서도 강력한 추론 규칙인 비교흡수 원리(Resolution principle)를 적용한다. 또한 증명이론을 메타술어로 표현할 수 있으므로 증명이론의 메타논리로 확장 가능하다. 메타논리가 모델 이론의 인식 논리(epistemic logic)보다 향상된 표현력을 기반으로 실용적인 면과 효율면에서 우월할 수 있다. 이를 입증하기 위해 인식 논리의 의미론과 증명이론의 메타논리 방식으로 각각 Muddy Children 문제에 적용한다. 그 결과 협력적 멀티에이전트 환경에서 메타논리를 사용하여 지식과 공통지식을 표현하고 추론한 방법이 더 효율적임을 증명한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권1호
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• pp.22-29
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• 2007

Two fuzzy controllers defined by 2 input variables cooperate to control a cartpole system in terms of balancing as well as centering. The cooperation is due to the BOXES scheme that selects one of the fuzzy controllers for each time step according to the content of box that is established through the critic of the control action by the fuzzy controllers. It is found that the control scheme is good at controlling the cartpole system so that the system is stabilized fast while the BOXES develops its ability to select proper fuzzy controller through experience.

• Transactions on Control, Automation and Systems Engineering
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• 제1권2호
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• pp.147-152
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• 1999

It is an interesting area in the field of artifical intelligence to find an analytic model of cooperative structure for multiagent system accomplishing a given task. Usually it is difficult to design controllers for multi-agent systems without a comprehensive knowledge about the system. One of the way to overcome this limitation is to implement an evolutionary approach to design the controllers. This paper introduces the use of a genetic algorithm to discover a fuzzy logic controller with rules that govern emergent agents solving a pursuit problem in a continuous world. Simulation results indicate that, given the complexity of the problem, an evolutionary approach to find the fuzzy logic controller seems to be promising.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.507-512
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• 1998

It is an interesting area in the field of artificial intelligence to and an analytic model of cooperative structure for multi-agent system accomplishing a given task. Usually it is difficult to design controllers for multi-agent systems without a comprehensive knowledge about the system. One of the way to overcome this limitation is to implement an evolutionary approach to design the controllers. This paper introduces the use of a genetic algorithm to discover a fuzzy logic controller with rules that govern emergent co-operative behavior: A modified genetic algorithm was applied to automating the discovery of a fuzzy logic controller jot multi-agents playing a pursuit game. Simulation results indicate that, given the complexity of the problem, an evolutionary approach to and the fuzzy logic controller seems to be promising.

• Journal of the Korean Data and Information Science Society
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• 제22권2호
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• pp.269-285
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• 2011

이동 애드-혹 망에서 자주 액세스되는 데이터의 캐싱은 데이터 액세스 성능 및 가용성을 향상시킬 수 있는 잠재적 기술이다. 다수의 클라이언트들 간의 캐시된 데이터의 공유와 협동을 허용하는 협력 캐싱은 캐싱 기술의 잠재력을 더 향상시킬 수 있다. 이 논문에서, 우리는 이동 애드-혹 망을 위한 클러스터 기반 퍼지 협력 캐싱 방법을 제안한다. 그리고 제안된 방법의 성능은 분석적 모델을 통해 평가하고, 그것의 성능을 다른 모바일 협력 캐싱 방법과 비교한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권3호
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• pp.185-190
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• 2002

In distributed autonomous robotic systems (DARS), each robot must behave by itself according to its states ad environments, and if necessary, must cooperate with other robots in order to carry out their given tasks. Its most significant merit is that they determine their behavior independently, and cooperate with other robots in order to perform the given tasks. Especially, in DARS, it is essential for each robot to have evolution ability in order to increase the performance of system. In this paper, a schema co-evolutionary algorithm is proposed for the evolution of collective autonomous mobile robots. Each robot exchanges the information, chromosome used in this algorithm, through communication with other robots. Each robot diffuses its chromosome to two or more robots, receives other robot's chromosome and creates new species. Therefore if one robot receives another robot's chromosome, the robot creates new chromosome. We verify the effectiveness of the proposed algorithm by applying it to cooperative search problem.