• Journal of applied mathematics & informatics
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• 제41권2호
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• pp.229-245
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• 2023

In this paper, we consider cooperative elliptic systems under conjugation conditions. We first prove the existence of the state for 2 × 2 cooperative elliptic systems with Dirichlet and Neumann conditions, then we find the set of equations and inequalities that characterizes the optimal control of distributed type for these systems. The case of n × n cooperative systems is also established.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.401-412
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• 2008

This paper discusses a design methodology of cooperative path planning for dynamical multi-agent systems with spatial and temporal constraints. The cooperative behavior of the multi-agent systems is specified in terms of the objective function in an optimization formulation. The path of achieving cooperative tasks is then generated by the optimization formulation constructed based on a differential flatness approach. Three scenarios of multi-agent tasking are proposed at the cooperative task planning framework. Given agent dynamics, both spatial and temporal constraints are considered in the path planning. The path planning algorithm first finds trajectory curves in a lower-dimensional space and then parameterizes the curves by a set of B-spline representations. The coefficients of the B-spline curves are further solved by a sequential quadratic programming solver to achieve the optimization objective and satisfy these constraints. Finally, several illustrative examples of cooperative path/task planning are presented.

• 한국도서관정보학회지
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• 제35권1호
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• pp.19-49
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• 2004

본 연구는 우리나라 통합 도서관 협력체제 구축을 위한 모델 개발을 목적으로 하였다. 현재 국내도서관 협력체제의 현황은, 국립중앙 도서관을 중앙관으로 한 공공도서관 협력망을 비롯하여 지역별 관종별 협력체제가 구축되어 도서관 기능의 활성화를 도모하고 있으나 기능적으로 보다 효율적인 협력이 필요한 시점에 있다. 이러한 관점에서 다양한 형태의 국내도서관 협력체제를 정비하여 새로운 통합 도서관 협력체제를 구축하기 위한 모델을 제시하였다.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.282-287
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• 2008

In distributed mobile robot systems, autonomous robots accomplish complicated tasks through intelligent cooperation with each other. This paper presents behavior learning and online distributed evolution for cooperative behavior of a group of autonomous robots. Learning and evolution capabilities are essential for a group of autonomous robots to adapt to unstructured environments. Behavior learning finds an optimal state-action mapping of a robot for a given operating condition. In behavior learning, a Q-learning algorithm is modified to handle delayed rewards in the distributed robot systems. A group of robots implements cooperative behaviors through communication with other robots. Individual robots improve the state-action mapping through online evolution with the crossover operator based on the Q-values and their update frequencies. A cooperative material search problem demonstrated the effectiveness of the proposed behavior learning and online distributed evolution method for implementing cooperative behavior of a group of autonomous mobile robots.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.81-82
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• 2006

Most work on cooperative diversity has assumed that the cooperating group (source and partners) and the associated average channel conditions between terminals (source, partners, and destination) are predetermined. In practical situations, however, it is important to develop the efficient algorithms for assigning the terminals with good inter-user channels for cooperating groups. In this paper, we propose the partner assignment algorithm for cooperative diversity in mobile communication systems. The proposed partner assignment algorithm is investigated by using the path loss model for mobile communication systems. Numerical results show that the proposed partner assignment algorithm provides the comparable probability of cooperative transmission to the partner assignment algorithm using exhaustive search. The probability of cooperative transmission increases with the number of users, which gives potential benefits of practical implementation to user cooperation in mobile communication systems.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.14-23
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• 2023

The cooperative communication systems using MIMO(multiple input multiple-output) relay are known as one of the most promising techniques to improve the performance and coverage of wireless communication systems. In this paper, we propose the cooperative communication systems using the relay with multi-antennas and DSTC(distributed space time coding) for decode-and-forward protocol. As using DSTC for DF(decode-and-forward), we can minimize the risk of error propagation at the wireless system using relay system. Also, the MIMO channel cab be formed by multi-antenna and DSTC at the MS(mobile station)-RS(relay station) and at the RS-BS(base station).Therefore, obtaining truly constructive the MIMO diversity and cooperative diversity gain from the proposed approach, the performance of system can be more improved than one of conventional system (relay with single antenna, no relay). The improvement in bit error rate is investigated through numerical analysis of the cooperative communication system with the proposed approach.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1387-1391
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• 2003

The fundamental aim of this paper is to present a solution algorithm to achieve cooperative contour controlling, under joint acceleration constraint with maximum cooperative speed. Usually, the specifications like maximum velocity of cooperative trajectory are determined by the application itself. In resolving the cooperative trajectory into two complementary trajectories, an optimum task resolving strategy is employed so that the task assignment for each robot is fair under the joint acceleration constraint. The proposed algorithm of being an off-line technique, this could be effectively and conveniently extended to the existing servo control systems irrespective of the computational power of the controller implemented. Further, neither a change in hardware setup nor considerable reconfiguration of the existing system is required in adopting this technique. A simulation study has been carried out to verify that the proposed method can be realized in the generation of complementary trajectories so that they could meet the stipulated constraints in simultaneous maneuvering.

• 대한수학회보
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• 제51권3호
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• pp.789-801
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• 2014

In this paper, we study the existence of ground state solutions for a class of non-resonant cooperative elliptic systems by a variant weak linking theorem. Here the classical Ambrosetti-Rabinowitz superquadratic condition is replaced by a general super quadratic condition.

• 한국통신학회논문지
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• 제33권9C호
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• pp.661-668
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• 2008

본 논문에서는 STO(Symbol Timing Offset)를 갖는 cooperative SFBC-OFDM 시스템에 적합한 파일럿 톤 기반의 채널 추정 기법을 제안한다. Cooperative SFBC-OFDM 시스템에서는 MS(Mobile Station)의 위치에 따라 RS(Relay Station)와 MS간 STO가 다르게 발생하며 이 STO가 위상 회전 형태로 왜곡을 발생시키기 때문에 orthogonal 파일럿 사용시 위상과 크기에 대하여 선형 보간을 취하여 채널을 추정하는 방법을 제안한다. 또한 orthogonal code를 사용하는 파일럿 구조에서는 비선형 방정식의 해를 구함으로써 채널 추정을 수행하는 방법을 제안한다. STO를 갖는 cooperative SFBC-OFDM 시스템에서 제안된 기법을 적용할 경우에 채널 추정 성능이 크게 개선될 수 있음을 모의실험을 통하여 확인한다.

• Journal of Mechanical Science and Technology
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• 제19권9호
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• pp.1720-1730
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• 2005

Automatic guided vehicle in the factory has an important role to advance the flexible manufacturing system. In this paper, we propose a novel object-transportation control algorithm of cooperative AGV systems to apply decentralized control to multiple AGV systems. Each AGV system is under nonholonomic constraints and conveys a common object-transportation in a horizontal plain. Moreover it is shown that cooperative robot systems ensure stability and the velocities of augmented systems convergence to a scaled multiple of each desired velocity field for cooperative AGV systems. Finally, the application of proposed virtual passivity-based decentralized control algorithm via system augmentation is applied to trace a circle. Finally, the simulation and experimental results for the object-transportation by two AGV systems illustrates the validity of the proposed virtual-passivity decentralized control algorithm.