• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.541-543
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• 2004

TCP does not distinguish between congestion and packet losses due to route change and link failures, which are prevalent in mobile ad hoc networks. So, TCP does not show satisfactory performance in ad hoc networks since it assumes that all packet losses are due to network congestions. In particular, when a route is reestablished it needs to be adaptively determined CWND according to the new route features. In this paper, we proposed CWND adjustment scheme to improve the TCP performance overad hoc networks. TCP sender effectively adjusts CWND by monitoring the network situation using control packets. Simulation results using NS-2 show that the proposed scheme increases TCP throughput compared with those of general TCP.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.3
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• pp.75-82
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• 2001

The continuous chip in turning operation deteriorates the precision of workpiece and can cause a hazardous condition to operator. Thus the chip form becomes a very important task for reliable turning process. The chip form is identified using the neural network of supervise data Through the measurement of energy radiated from the chip. The feed mechanism os adjusted in order to break continuous chip according to the result of the chip form recognition and it shows a good approach for precision turning operation.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4E
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• pp.24-30
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• 2001

This paper describes a fast harmonic estimation, referred to as Delta Adjustment (DA), using a low resolution pitch. The presented DA method is based on modification of the Generalized Dual Excitation (GDE) technique[1] which was proposed to improve speech enhancement performance. We introduce the GDE technique and modify it to be suitable for low bit rate harmonic coding that uses only an integer pitch estimate. Unlike the GDE, the DA matches a frequency-warped version of the original spectrum that conforms to a fixed pitch at all harmonic bands. In addition, complexity and performance of the presented method are described in comparison with those of the conventional Fractional Pitch (FP) based harmonic estimation. Experimental results showed that the DA algorithm significantly reduces the complexity of the FP method while maintaining the performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.4
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• pp.135-150
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• 1982

Nowadays, The function of telecommunication contributes to maintaining the peace of the world, and the international cooperation in the communication field can not be emphasized too much. The pioneers in telecommunication field dvoted their lives to the infinite love for humanity. However, the modern communication system in our country was initiated, in the later part of the Lee-Dynasty, not for the international cooperation but for the invasive avarices of the neighbouring nations such as Japan and China. The true international cooperation should be based on the love of humanity and the peace of the world such as the pioneers'. This paper proposes to resarch the historic process of initiation and development of the international organs relating to telecommunication as well as the international telecommunication network. Finally, I will make the following suggestions for the promotive direction of the true international cooperation. 1. Intensification of the radio administrative power. 2. Promotion of the international cooperation on the man-power and economy in telecommunication field. 3. Establishment and adjustment of research institutes of telecommunication. 4. Promotion of space communications. 5. Establishment of the world telecommunication network for world-wide peace.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.379-383
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• 1997

This paper focuses on self-organization of fuzzy rules for performance management of computer communication networks serving manufacturingsystems. The performance managment aims to improve the network performance in handling various types of messages by on-line adjustment of protocol parameters. The principle of fuzzy logic has been used in repressenting the knowledge of human expert on the performance management and in deriving manafement decisions. In this paper, we present an of this self-organization is domonstrated by discrete simulation of an IEEE 802.4 network.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.404-413
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• 1997

Direct-drive robots are suitable to position and force control with high accuracy, but it is difficult to design a controller which gives satisfactory perfonnance because of the system's nonlinearity and link-interactions. This paper is concerned with the force control of direct-drive robots. The pro¬posed algorithm consists of feedback controllers and a neural network. Mter the completion of learning, the outputs of feedback controllers are nearly equal to zero, and the neural network con¬troller plays an important role in the control system. Therefore, the optimum adjustment of parameters of feedback controllers is unnecessary. In other words, the proposed algorithm does not need any knowledge of the controlled system in advance. The effectiveness of the proposed algo¬rithm is demonstrated by the experiment on the force control of a parallelogram link-type direct¬drive robot.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.431-431
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• 2000

The modeling of 5-bar linkage robot manipulator dynamics by means of a mathematical and neural architecture is presented. Such a model is applicable to the design of a feedforward controller or adjustment of controller parameters. The inverse model consists of two parts: a mathematical part and a compensation part. In the mathematical part, the subsystems of a 5-bar linkage robot manipulator are constructed by applying Kawato's Feedback-Error-Learning method, and trained by given training data. In the compensation part, MLP backpropagation algorithm is used to compensate the unmodeled dynamics. The forward model is realized from the inverse model using the inverse of inertia matrix and the compensation torque is decoupled in the input torque of the forward model. This scheme can use tile mathematical knowledge of the robot manipulator and analogize the robot characteristics. It is shown that the model is reasonable to be used for design and initial gain tuning of a controller.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.1
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• pp.51-58
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• 1998

The goal of this study is to propose a precision improvement scheme for long baseline determination based on the use of IGS ephemeris and different cutoff angles. It is also to present the adjustment results of ’96 Korea GPS fiducial network. In order to obtain more accurate coordinates in precise geodetic surveying, the revision of specification is necessary for the field operation and procedure of baseline processing.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.15-24
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• 1994

In order to produce a consistent set of coordinates of the Korea Precise Primary Geodetic Network (PPGN) based on Suwon Datum, PPGN survey with the use of EDM had carried out between 1975 and 1993. In this study, data arrangement and rigorous adjustment was carried out to assess the net strength and local weakness and to evaluate the accuracy of PPGN. ss, specification for PPGN survey would be systematically studied and revised to new technology and field conditions. And basic data for redefinition of official coordinates. of 1st and 2nd triangulation points is obtained.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.390-393
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• 1997

Fuzzy logic and neural networks are complemetary technologies in the design of intelligent system. Fuzzy neural network(FNN) as an auto-tuning method is actually known to an excellent method for the adjustment of the fuzzy rule. However, this has a weak point, because the convergence to the optimum depends on the initial condition. In this paper we develop a coding format to determine a FNN model by chromosome in GA and present systematic approach to identify the parameters and structure of FNN. The proposed hybrid tuning method realizes to construct minimal and optimal structure of the fuzzy mode simultaneously and automatically. This paper shows effectiveness of the tuning system by simulations compared with conventional methods.