• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.831-836
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• 2010

In real system application, the path planning and following system for the coordinated control of heterogeneous marine robots based on the underwater acoustic communication has the following problems: surface and underwater robots have different maneuvering properties, an underwater robot requires more effective operating, it has a limited communication range because of the transmission loss (TL) of acoustic wave, it has a communication error because of the Doppler distortion of acoustic wave, and further, it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent path planning algorithm using the evolution strategy (ES) and the fuzzy logic controller (FLC) based on system modeling, is proposed. To verify the performance of the proposed algorithm, the path planning and following of an underwater robot is performed according to the maneuvering of a surface robot. Simulation results show that the proposed algorithm effectively solves the problems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.55-61
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• 2009

This paper proposes a position estimation of a mobile robot based on USN(Ubiquitous Sensor Network) and encoder, and development of tele-operation system using Internet. USN used in experiments is based on ZigBee protocol and has location estimation engine which uses RSSI signal to estimate distance between nodes. By distortion the estimated distance using RSSI is not correct, compensation method is needed. We obtained fuzzy model to calculate more accurate distance between nodes and use encoder which is built in robot to estimate accurate position of robot. Based on proposed position estimation method, tele-operation system was developed. We show by experiment that proposed method is more appropriate for estimation of position and remote navigation of mobile robot through Internet.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.602-608
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• 2011

In this study, a method of designing a neurointerface using neural network (NN) is proposed for controlling nonholonomic mobile robots. According to the concept of virtual master-slave robots, in particular, a partially stable inverse dynamic model of the master robot is acquired online through the NN by applying a feedback-error learning method, in which the feedback controller is assumed to be based on a PD compensator for such a nonholonomic robot. The NN for the online feedback-error learning can composed that the input layer consists of six units for the inputs $x_i$, i=1~6, the hidden layer consists of two hidden units for hidden outputs $o_j$, j=1~2, and the output layer consists of two units for the outputs ${\tau}_k$, k=1~2. A tracking control problem is demonstrated by some simulations for a nonholonomic mobile robot with two-independent driving wheels. The initial q value was set to [0, 5, ${\pi}$].

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1101-1105
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• 2011

Radiation particles can introduce temporary errors in memory systems. To protect against these errors, so-called soft errors, error detection and correcting codes are used. In addition, scrubbing is applied which is a fundamental technique to avoid the accumulation of soft errors. This paper introduces an optimal scrubbing scheme, which is suitable for a system with auto error detection and correction logic. An auto error detection and correction logic can correct soft errors without CPU's writing operation. The proposed scrubbing scheme leads to maximum reliability by considering both allowable scrubbing load and the periodic accesses to memory by the tasks running in the system.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.2
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• pp.228-233
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• 2000

It is common to apply the technology of FPGA (Fie이 Programmable Gate Array) which is one of the design methods for ASIC(Application Specific IC)to the active components used in the data processing at the digital system of satellite aircraft missile etc for compact lightness and integration of Printed Circuit Board (PCB) In carrying out the digital data processing the FPGAs are designed for the various functions of the Process Control Interrupt Control Clock Generation Error Detection and Correction (EDAC) as the individual module. In this paper an FPGA chip for Single Error Correction and Double Error Detection (SEC-DED) for EDAC is designed and simulated by using a VLSI design software LODECAP.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1040-1047
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• 2011

This paper proposes a novel method based on error back propagation neural networks to fuse laser sensor data and ultrasonic sensor data for enhancing the accuracy of mapping. For navigation of single robot, the robot has to know its initial position and accurate environment information around it. However, due to the inherent properties of sensors, each sensor has its own advantages and drawbacks. In our system, the robot equipped with seven ultrasonic sensors and a laser sensor navigates to map two different corridor environments. The experimental results show the effectiveness of the heterogeneous sensor fusion using an error backpropagation algorithm for mapping.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.299-302
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• 2002

Error detection and correction using CRC and the general class of cyclic codes is an important part of designing reliable data transmission schemes. The decoding method for cyclic codes using covering patterns is easily-implementable, and its complexity de-pends on the number of covering patterns employed. Determination of the minimal set of covering patterns for a given code is an open problem. In this paper, an efficient search method for constructing minimal sets of covering patterns is proposed and compared with several existing search methods. The result is applicable to various codes of practical interest.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.853-858
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• 1993

The error back-propagation(BP) algorithm is widely used for finding optimum weights of multi-layer neural networks. However, the critical drawback of the BP algorithm is its slow convergence of error. The major reason for this slow convergence is the premature saturation which is a phenomenon that the error of a neural network stays almost constant for some period time during learning. An inappropriate selections of initial weights cause each neuron to be trapped in the premature saturation state, which brings in slow convergence speed of the multi-layer neural network. In this paper, to overcome the above problem, Micro-Genetic algorithms(.mu.-GAs) which can allow to find the near-optimal values, are used to select the proper weights and slopes of activation function of neurons. The effectiveness of the proposed algorithms will be demonstrated by some computer simulations of two d.o.f planar robot manipulator.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1416-1419
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• 1996

현재 많은 공장에서 사용중인 사출기나 프레스를 중앙 집중식 제어를 위한 다양한 시도가 있었다. 이러한 시도는 많은 공장 자동화와 이를 기본으로 한 생산관리 시스템을 구축함으로서 제품의 품질을 향상시킬수 있을 뿐만 아니라 장비의 오동작을 중앙에서 감시, 감독하여 장비의 효율을 최대화함으로 생산성을 증대하여 기업의 이윤을 최대화 할수 있다는 장점이 있다. 그러나 공장 자동화의 단계는 초기 단계로 여러가지 문제점을 안고 있으며 현 상태의 시스템으로 위의 여러가지 장점을 얻기에는 어려운 실정에 있으며 그 시스템의 운영에도 많은 문제점이 발견되어 운영 불가능 상태로 방치된 이 시점에서 이러한 문제점을 분석하여 최대한으로 현재 개발된 시스템의 오류를 수정 및 보완하여 효과적인 공장 자동화를 위한 시스템을 완성함으로서 생산의 향상과 기업의 원활한 생산 활동을 지원하고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.967-973
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• 2009

The model matching problem of asynchronous sequential machines is to design a corrective controller such that the stable-state behavior of the closed-loop system matches that of a prescribed model. In this paper, we address model matching when the external input set consists of controllable inputs and uncontrollable ones. Like in the frame of supervisory control of Discrete-Event Systems (DES), uncontrollable inputs cannot be disabled and must be transmitted to the plant without any change. We postulate necessary and sufficient conditions for the existence of a corrective controller that solves model matching despite the influence of uncontrollable events. Whenever a controller exists, the algorithm for its design is outlined. To illustrate the physical meaning of the proposed problem, the closed-loop system of an asynchronous machine with the proposed control scheme is implemented in VHDL code.