• International Journal of Aeronautical and Space Sciences
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• 제8권2호
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• pp.107-120
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• 2007

Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

• Journal of Multimedia Information System
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• 제3권4호
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• pp.129-134
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• 2016

A routing protocol in mobile ad hoc networks is important, and a location based routing has attracted attention. We have proposed a method, in which plural mobile agents (MA) manage location information and construct a route and the number of MA dynamically changes depending on the network situation. However, the area where each MA manages is not always appropriate. This would increase the network load due to unnecessary split and mergence of MAs. To solve this problem, in this paper, we propose an enhanced method. In this method, the MA management area is properly determined based on distribution of nodes. From the performance evaluation, we show that the proposed method outperforms conventional methods in terms of packet delivery rate when network load is high.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 추계학술발표논문집 (상)
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• pp.301-304
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• 2000

전자상거래 지원 시스템에서 판매지원 에이전트는 고객의 취향을 파악하여 구매자에게 가장 적절한 상품을 탐색하여 사용자의 만족도를 극대화할 수 있어야 한다. 이에 인공지능 기법에 하나인 사례기반 추론기법을 이용한 판매지원 에이전트와 감성공학을 응용한 신제품 디자인 개발지원 에이전트를 결합한 다중 에이전트 시스템을 제안하고자 한다.

• International Journal of Computer Science & Network Security
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• 제24권4호
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• pp.147-154
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• 2024

The continuous increase in urban population due to migration of mases from rural areas to big cities has set urban water supply under serious stress. Urban water resources face scarcity of available water quantity, which ultimately effects the water supply. It is high time to address this challenging problem by taking appropriate measures for the improvement of water utility services linked with better understanding of demand side management (DSM), which leads to an effective state of water supply governance. We propose a dynamic framework for preventive DSM that results in optimization of water resource management. This paper uses Agent Based Modeling (ABM) with Digital Twin (DT) to model water consumption behavior of a population and consequently forecast water demand. DT creates a digital clone of the system using physical model, sensors, and data analytics to integrate multi-physical quantities. By doing so, the proposed model replicates the physical settings to perform the remote monitoring and controlling jobs on the digital format, whilst offering support in decision making to the relevant authorities.

• Journal of Advanced Marine Engineering and Technology
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• 제39권10호
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• pp.1031-1036
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• 2015

Proportional-integral-derivative (PID) controllers are widely used in industrial sites. Most tuning methods for PID controllers use an empirical and experimental approach; thus, the experience and intuition of a designer greatly affect the tuning of the controller. The representative methods include the closed-loop tuning method of Ziegler-Nichols (Z-N), the C-C tuning method, and the Internal Model Control tuning method. There has been considerable research on the tuning of PID controllers for single-input single-output systems but very little for multi-input multi-output systems. It is more difficult to design PID controllers for multi-input multi-output systems than for single-input single-output systems because there are interactive control loops that affect each other. This paper presents a tuning method for the PID controller for a two-input two-output system. The proposed method uses a real-coded genetic algorithm (RCGA) as an optimization tool, which optimizes the PID controller parameters for minimizing the given objective function. Three types of objective functions are selected for the RCGA, and each PID controller parameter is determined accordingly. The performance of the proposed method is compared with that of the Z-N method, and the validity of the proposed method is examined.

• 대한토목학회논문집
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• 제34권5호
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• pp.1609-1623
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• 2014

최근 건설분야에 적용될 수 있는 자동화 시스템 개발을 위한 연구가 많이 수행되고 있다. 자동화 기술 적용시 효과가 높은 공종 중에서 건설기계의 의존도가 높고, 건축 및 토목공사에서 기본 공종인 토공을 대상으로 연구가 진행되어 왔다. 공사현장의 모델을 구축하여 자동화 시스템이 토공계획을 수립할 수 있는 기술과 단일 건설장비가 주어진 정보와 환경을 인지하여 작업을 수행할 수 있도록 하는 기술이 개발되었다. 자동화 토공시스템이 현장에 적용되기 위해서 해결되어야 할 문제들이 여전히 많이 있지만, 그중에서 중요한 한 가지가는 다수 및 다종의 건설장비들이 협업작업을 수행할 수 있도록 하는 기술을 제공해야만 하는 것이다. 본 연구에서는 사람들의 협업시스템과 의사결정 방법을 모방한 건설시공 시스템을 개발하는 것을 목표로 하고 있으며, 시스템 개발을 위하여 인공지능 분야에서 사용하고 있는 멀티에이전트 개념을 적용하였다. 멀티에이전트 기반 시스템 개발을 위하여 에이전트의 구성과 기능을 제안하고 있으며, 에이전트간 협업 및 중재를 위한 프레임워크를 제시하였다. 그리고 투입되는 건설장비인 다수의 굴삭기와 다짐장비의 효율적인 진로계획과 협업작업시 간섭효과의 최소화 및 중복작업 방지를 위한 방안도 제시하였다. 아직은 이론적인 개념을 제시하고 있는 단계로 가상 시뮬레이션에 의하여 효과를 검증하고 있으나, 추후에는 물리적인 시스템의 구축을 통하여 현장에 적용하기 위한 실증연구를 수행해야 할 것이다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권2호
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• pp.95-103
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• 2016

In a dynamic environment autonomous robots often encounter unexpected situations that the robots have to deal with in order to continue proceeding their mission. We propose an adaptive goal-based model that allows cyber-physical systems (CPS) to update their environmental model and helps them analyze for attainment of their goals from current state using the updated environmental model and its capabilities. Information exchange approach utilizes Human-Agent-Robot-Machine-Sensor (HARMS) model to exchange messages between CPS. Model validation method uses NuSMV, which is one of Model Checking tools, to check whether the system can continue its mission toward the goal in the given environment. We explain a practical set up of the model in a situation in which homogeneous robots that has the same capability work in the same environment.

• Journal of Information Technology Applications and Management
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• 제21권3호
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• pp.65-77
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• 2014

Ubiquitous learning has aroused great interest and is becoming a new way for foreign language education in today's society. However, how to increase the learners' initiative and their community cohesion is still an issue that deserves more profound research and studies. Emotional intelligence can help to detect the learner's emotional reactions online, and therefore stimulate his interest and the willingness to participate by adjusting teaching skills and creating fun experiences in learning. This is, actually the new concept of smart education. Based on the previous research, this paper concluded a neural mechanism model for analyzing the learners' emotional characteristics in ubiquitous environment, and discussed the intelligent monitoring and automatic recognition of emotions from the learners' speech signals as well as their behavior data by multi-agent system. Finally, a framework of emotional intelligence system was proposed concerning the smart foreign language education in ubiquitous learning.

• 제어로봇시스템학회논문지
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• 제18권8호
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• pp.758-767
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• 2012

In the ad-hoc wireless network environment, that the fixed sensor nodes and the sensor nodes to move are mixed, as the number of the sensor nodes with mobility are getting more, the costs to recover and maintain the whole network will increase more and more. This paper proposed the CDSR (Cost based Dynamic Source Routing) algorithm being motivated from the typical DSR algorithm, that is one of the reactive routing protocol. The cost function is defined through measuring the cost which any sensor node pays to participate in the whole network for communication. It is also showed in this paper that the proposed routing algorithm will increase the efficiency and life of whole sensor network through a series of experiments.

• 전자공학회논문지CI
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• 제48권3호
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• pp.36-45
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• 2011

소셜러닝의 대표적 학습인 협력학습에서의 에이전트란 학습자에게 현황이든, 환경이든, 과제이든 설명해 줄 수 있거나, 보편적이고 일반적인 방법으로 독립적인 기능을 수행할 수 있는 것이다, 이를 위해서는 에이전트 사이에서의 의사소통에 관한 정보기술 표준화 방법이 요구된다. 본 연구는 협력학습에서 사용되는 각종 에이전트들의 의사소통에 관한 데이터 모델에 관한 기술을 제시한다. 따라서 이러닝 협력학습 환경을 지원하는 많은 에이전트들의 유형을 파악하고, 이 에이전트들 간의 상호 의사소통에 관한 규칙을 갖는 데이터 모델을 설계하여 그 요소들을 정의하고자 한다. 이렇게 제시된 표준화된 데이터 모델을 기반으로 하는 다중 에이전트 시스템은 여러 응용 에이전트가 독립된 프로세스로 활동할 수 있도록 정의된 통신 데이터모델에 의해 메시지 상호 교환이 가능해진다. 본 연구는 소셜러닝에서 주를 이루는 학습방법인 협력학습 중에서 다양한 에이전트를 활용하는 경우 이를 지원하는 에이전트간의 통신에 관한 의사소통 모델 응용을 통해 원활한 협력학습이 구현되도록 기여할 것으로 기대한다.