• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1337-1340
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• 2002

웹 정보검색에서 웹 문서를 수집하고, 색인을 구축하는 작업에서 Web Crawler 의 역할은 매우 중요하다. 그러나, 웹 문서의 급속한 증가로 인하여 Web Crawler 가 모든 웹 문서를 수집하는 것은 불가능하며, 웹 정보검색의 정확성을 증가시키기 위한 방법으로 특정한 영역의 문서를 수집하는 focused web crawler에 대한 연구가 활발히 진행되어 왔다. 이와 함께, 웹 문서의 link구조를 이용하여 문서의 집합에서 중요한 문서를 찾는 연구들이 많이 진행되었다. 그러나, 기존의 연구에서는 문서의 link 구조에만 초점이 맞추어져 있으며, hypertext 전체의 연결 구조를 알아야 한다는 문제점이 있다. 본 연구에서는 hyperlink의 구조와 hypertext 분류방법을 이용하여 문서에 연결된 다른 문서 중 중요한 문서를 결정하는 방법을 제시하고 이를 이용한 web crawler 를 통하여 특정영역에서 정확한 문서를 수집함을 보였다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.327-328
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• 2014

This paper presents a pulse density modulation (PDM) technique with a high frequency link for a dual output DC-DC converter. The proposed scheme consists of a fixed frequency AC link and independent PDM controllers for the output regulation, which provides a simple structure and higher efficiency. The simulation and experimental results are provided to show the effectiveness of the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.539-546
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• 2004

Conventional robot manipulators actuated by motors with the speed reducer such as the harmonic drive have weakness in the load capacity, since the speed reducer does not have enough strength. To overcome this, a new type of the robot actuator based on the four-bar-link mechanism driven by the ball screw was proposed and constructed. Also, a new type of a revolute-jointed robot manipulator composed of the developed actuators was developed. The base axis is actuated by the motor with the conventional speed reducer, but the other axes are actuated by the proposed actuators. The kinematics and dynamics of the robot were analyzed, and the performance test of the robot was made. Through the test results, the performance of superior load capacity versus the robot weight is shown.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.139-141
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• 2019

Capacitive power transfer has an advantage in the simplicity of the energy link structure. So, the conventional phase -shift full bridge sometime is not always the best choice because of its complexity and high cost. On the other hand, the link capacitance is usually very low and requires high-frequency operation, but, the series resonant converter loses zero-voltage switching feature in the light load condition, which makes the switching loss high especially in CPT system. The paper proposes a new low-cost topology based on asymmetric half-bridge to achieve simplicity as well as wide zero voltage switching range. The design procedure is presented, and circuit operations are analyzed and verified by simulation.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.207-213
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• 2021

Networks in Mobile ad hoc contain distribution and do not have a predefined structure which practically means that network modes can play the role of being clients or servers. The routing protocols used in mobile Ad-hoc networks (MANETs) are characterized by limited bandwidth, mobility, limited power supply, and routing protocols. Hybrid routing protocols solve the delay problem of reactive routing protocols and the routing overhead of proactive routing protocols. The Ant Colony Optimization (ACO) algorithm is used to solve other real-life problems such as the travelling salesman problem, capacity planning, and the vehicle routing challenge. Bio-inspired methods have probed lethal in helping to solve the problem domains in these networks. Hybrid routing protocols combine the distance vector routing protocol (DVRP) and the link-state routing protocol (LSRP) to solve the routing problem.

• Honam Mathematical Journal
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• v.44 no.2
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• pp.296-309
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• 2022

In this paper, we establish the Fricke Group Γ_F (N) which is a new special group of Non-Euclidean Crystallograhic (NEC) group. We obtain this group whose congruence subgroup Γ₀(N) is expanded with Fricke reflection $F(z)={\frac{1}{N{\bar{z}}}}$. Then, we research and calculate the structure of signature and fundamental domain of this group. And then, we calculate the number of boundary components in the signature for this group. Finally, we find the 2, 3, ∞ valued link periods of these boundary components with the H. Jaffee technique.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.176-183
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• 2009

This study was intended to define the spatial concept of the boundary structure of the architectural space as well as evaluate the Hyangdan which well represents the features of Korean traditional building in such a way of reviewing the building structure of Korean traditional residential space. The boundary is categorized into visible boundary and invisible boundary which was also functionally classified into the features of isolating, passing, mediating and overlapping. The major elements comprising the boundary structure was analyzed by the characteristic of the pattern so as to define them as the concept of surrounding, duality, hierarchism, continuity and overlapping. Based on such concepts, a boundary structural characteristics of Hyangdan were reevaluated and outlined as follows. The surrounding feature was seen through the outer side of the structure surrounded, two courtyards and eaves, and a duality showing both the closure of main house and openness of detached house was seen through the characteristics of surrounding structure. And the continuous activities toward the inner room and the empty space to link them in a systematic way and repeatedly aligned rooms reveal the overlapping as continuous and transitional space. And finally, an elevated stylobate demonstrates the hierarchical features of the structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1139-1144
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• 2012

The ration of payload to weight of industrial robot amounts form 1:10 to 1:30. Compared with man who have a ration of 3:1, it is very low. One of the goals for the next generation of robots will be a ration. This might be possible only by developing lightweight robots. When two-link flexible arm is rotated about an joint axis, transverse vibration may occur. In this paper, vibration dynamics of flexible arm is modeled by using Bernoulli-Euler beam theory and Lagrange equation. Using the fact that matrix $\dot{D}-2C$ is skew symmetric, new controllers which have a simplified structure with less computational burden is proposed by using Lyapunov stability theory. We propose deterministic and adaptive control laws for two link flexible arm, and the validity of the proposed control scheme is shown in computer simulation for two-link flexible arm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.2
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• pp.128-136
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• 2001

This paper evaluates the performance of an optic link in a frequency conversion based fiber-radio system. The proposed link structure simplifies a BS(base station) via making the MMW(millimeter wave) optical pilot tone generated in the CS(control station) be used in the uplink as well as in the downlink. To acquire the optical pilot tone, an EOM(electro-optic modulator) in the CS is biased in three different ways, i.e., MAB(maximum bias), MIB(minimum bias), QB(quadrature bias). We, depending on the biasing of the EOM, evaluate the link performances in two cases; one is for constant laser source power and the other for constant received DC optical power at a PD(photo detector). Based on the simulation results on the downlink CNR and the uplink SFDR(spurious free dynamic range), we finally deduce the effective EOM biasing for each case.

• Steel and Composite Structures
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• v.35 no.3
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• pp.305-325
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• 2020

Beams of steel frame-tube structures (SFTSs) typically have span-to-depth ratios of less than five. This makes a flexural beam unsuitable for such an application because the plastic hinges at the beam-ends cannot be adequately developed. This leads to lower ductility and energy dissipation capacities of SFTSs. To address this, SFTSs with bolted web-connected replaceable shear links (SFTS-BWSLs) are proposed. In this structural system, a web-connected replaceable shear link with a back-to-back double channel section is placed at the mid-length of the deep beam to act as a ductile fuse. This allows energy from earthquakes to be dissipated through link shear deformation. SFTS and SFTS-BWSL buildings were examined in this study. Several sub-structures were selected from each designed building and finite element models were established to study their respective hysteretic performance. The seismic behavior of each designed building was observed through static and dynamic analyses. The results indicate that the SFTS-BWSL and SFTS have similar initial lateral stiffness and shear leg properties. The SFTS-BWSL had lower strength, but higher ductility and energy dissipation capacities. Compared to the SFTS, the SFTS-BWSL had lower interstory drift, base shear force, and story shear force during earthquakes. This design approach could concentrate plasticity on the shear link while maintaining the residual interstory drift at less than 0.5%. The SFTS-BWSL is a reliable resistant system that can be repaired by replacing shear links damaged due to earthquakes.