This paper proposes a method for constituting the formation of a multi-robot system according to dynamically changing environments. First, we apply a method of multi-objective behavior coordination for integrating behavior outputs from the fuzzy control for collision avoidance and target tracing. Second, we apply a spring model to calculate the temporary target position of each robot for the formation behavior. Third, we discuss multi-robot behaviors based on the concept of coupling. The tight coupling is realized by the spring model while the loose coupling is realized by the individual decision making based on connection and disconnection with other robots. Furthermore, the proposed method is applied to the exploration in unknown environments. Finally, we discuss the effectiveness of the proposed method through several simulation results.

This paper addresses frequency assignment for singlelevel and multilevel SCPC systems. In order to obtain the optimum channel allocation, where the influence of intermodulation noise on carriers is minimized, a practical and effective method is proposed. The quasi-optimum, solutions obtained with the proposed method are presented for single-level SCPC systems, showing their advantage in intermodulation noise reduction. Concerning frequency assignment for multilevel SCPC systems, two strategies to realize the-quasi-optimum channel allocation are compared with regard to the improvement in carrier-to-intermodulation noise power ratio. The performance of the obtained channel allocation indicates the effectiveness of the proposed optimization method.

The high-rate punctured codes of rates 2/3 through 13/14 are derived from rate 1/2 specific convolutional codes with maximal free distance. Coding gains of derived codes are compared based on their bit error rate performances under soft decision Viterbi decoding.