• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.539-544
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• 1991

In order to verify robot motions for a desired work, it is necessary to visualize it on a computer screen. This paper presents a simulation algorithm for robot manipulator motion. Kinematic description is based on the Denavit- Hartenberg link representation. In order to be applied to various types of the robot manipulator, inverse kinematics make use of the Newton-Raphson iterative method with the least squares method. Joint variables are interpolated by the lowest polynomial segment satisfying acceleration continuity. The robot motions are generated and then animated on a computer screen in the form of skeleton type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1744-1759
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• 2000

In this paper a synchronized stream cryptosystem for secure link layer communication on a radio channel is designed. We have proposed new interleaving schemes to randomize a burst error and experimented with different types of interleaving schemes. The proposed techniques of interleaving schemes are : (1) interleaving scheme based on frame(2) interleaving scheme based on group. The proposed schemes are very robust in randomizing

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1398-1401
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• 1993

The computer users who desire the comprehensive use of an advanced network system which permits to link the diversified types of computer from one to others, still tend to increase in number. However, one of the ways to install a highly reliable facilities relative to the network system is to inherit the know-how preserved in the specific technology. Therefore, we will propose the solution of this problem. This paper describes COMNETS, an expert system for constructing distributed networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.300-302
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• 1999

The multicast routing trees that have recently been proposed can be classified into three types: source-based trees, renter-based shared trees and non-renter based shared trees. In this paper, those multicast trees are compared and evaluated in term of the link costs and the maximum delay on the tree by experiments.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.85-92
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• 2006

In this paper, we study a wireless cellular network design problem. It consists of selecting the location of the base station controllers and mobile service switching centres, selecting their types, designing the network into a tree-topology, and selecting the link types, while considering the location and the demand of base transceiver stations. We propose a constraint programming model and develop a heuristic combining local search and constraint programming techniques to find very good solutions in a reasonable amount of time for this category of problem. Numerical results show that our approach, on average, improves the results from the literature.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.59-64
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• 2001

This paper analyzes the performance of the several types of ACL(Asynchronous ConnectionLess) packets used in Bluetooth according to a BER(Bit Error Rate) and a packet length and proposes an optimal packet type and an optimal size of the packet being able to be used under the given BER. This paper proposes how to obtain the optimal packet type and the optimal size of the packet maximizing the performance measure under the given BER. In addition, this paper shows that the optimal type and size of the packet maximizing the throughput are different from those maximizing the mean transmission time. This occurs because the Bluetooth uses not only one type of packet but also various types of packets.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1308-1316
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• 2001

A hybrid type master system is proposed to take the advantage of the link mechanism and magnetic levitation mechanism without using a force sensor. Two different types of electromagnetic actuators, moving coil type and moving magnet types are used to drive the master system which is capable of 4-DOF actuation. It is designed that the rotation motions about x-y axis are decoupled and the whole system is represented by simple dynamic equations. The force reflection is achieved by using the simple relation between the force and applied current and position. The simulation and experimental results are presented to show its performance.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.364-367
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• 2008

Many different types of network equipments are deployed in a large-scale IP network. In this operating environment, network service providers suffer from difficulty in controlling various equipments simultaneously in case network faults happen in their overall or regional network due to physical link failure or abnormal traffic. This paper presents a policy-based methodology to control many different types of network equipments at the same time in abnormal cases. The key idea is that NMS(Network Management System) keeps vendor-neutral control policies in normal times and that when an abnormal case occurs in network, NMS transforms the selected policy into vendor-specific control commands and enforces them to various equipments simultaneously.

• Asia Marketing Journal
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• v.21 no.3
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• pp.65-82
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• 2019

This study examines the relationship between social media advertisement and customer interest in the context of luxury brands. Further, this study investigates the effective ways to utilize visual types (pictorial advertisement and video advertisement) and contents types (website link and hash-tag) in social media advertising by proposing a time-series model to estimate the long-term effect of social media advertising on social search. We find that the pictorial advertisements are more effective than video advertisements, which provides a different result from previous existing research. In addition, advertisements using hashtags are more effective than web links due to efficiency of the search feature. Finally, since the number of brand fans also have a positive effect on advertising interest, it is essential to utilize social media advertising for the enhancement of customers' interests. Confirming that the effectiveness of social media advertising varies depending on how the visual contents and text are presented, this research can help marketing managers to assess predicted outcomes of using various methods of social media advertising.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.428-451
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• 2010

Traffic matrix-based anomaly detection and DDoS attacks detection in networks are research focus in the network security and traffic measurement community. In this paper, firstly, a new type of unidirectional flow called IF flow is proposed. Merits and features of IF flows are analyzed in detail and then two efficient methods are introduced in our DDoS attacks detection and evaluation scheme. The first method uses residual variance ratio to detect DDoS attacks after Recursive Least Square (RLS) filter is applied to predict IF flows. The second method uses generalized likelihood ratio (GLR) statistical test to detect DDoS attacks after a Kalman filter is applied to estimate IF flows. Based on the two complementary methods, an evaluation formula is proposed to assess the seriousness of current DDoS attacks on router ports. Furthermore, the sensitivity of three types of traffic (IF flow, input link and output link) to DDoS attacks is analyzed and compared. Experiments show that IF flow has more power to expose anomaly than the other two types of traffic. Finally, two proposed methods are compared in terms of detection rate, processing speed, etc., and also compared in detail with Principal Component Analysis (PCA) and Cumulative Sum (CUSUM) methods. The results demonstrate that adaptive filter methods have higher detection rate, lower false alarm rate and smaller detection lag time.