• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.826-833
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• 2010

Electric-thermal-structural actuated compliant mechanisms are mechanisms onto which electric voltage drop is applied as input instead of force. This mechanism is based on thermal expansion of material while being heated. Compliant mechanisms are designed subjected to electric charge input using BESO(bi-directional evolutionary structural optimization) method. Reliability-based topology optimization (RBTO) is applied to the topology design of actuators. performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints. In this study, BESO method is used to obtain optimal topology of compliant mechanisms from initial design domain. PMA approach is used to evaluate reliability index. The procedure has been tested in numerical applications and compared with the results obtained by other methods to validate these approaches.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.501-509
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• 2011

In this paper, we propose an edge profile adaptive bi-directional diffusion interpolation method which consists of shock filter and level set. In recent years many interpolation methods have been proposed but all methods have some degrees of artifacts such as blurring and jaggies. To solve these problems, we adaptively apply shock filter and level set method where shock filter enhances edge along the normal direction and level set method removes jaggies artifact along the tangent direction. After the initial interpolation, weights of shock filter and level set are locally adjusted according to the edge profile. By adaptive coupling shock filter with level set method, the proposed method can remove jaggies artifact and enhance the edge. Experimental results show that the average PSNR and MSSIM of our method are increased, and contour smoothness and edge sharpness are also improved.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.479-480
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• 2010

In this paper, the bi-directional soft switching DC-DC converter using ZCT(Zero Current Transition) method is proposed for using battery application system. This topology is composed of soft switching bi-directional buck/boost converter having the ZCT auxiliary circuit with two switches, two resonant capacitors, one resonant inductor. Therefore, the proposed topology can reduce switching loss. To verify the validity of the proposed topology, theoretical analysis and simulation results are presented.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1137-1140
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• 2003

인터넷 mobility 기술의 발전으로 인해 Mobile IPv6 를 기반으로 하는 이동 네트워크(Mobile Network, NEMO)기술이 등장하였으며, MR(Mobile Router)와 HA(Home Agent)간의 bi-directional 터널을 통해 네트워크의 이동성을 지원한다. 그러나. 이동네트워크 안에 또 다른 이동네트워크가 존재하는 중첩된 이동네트워크에서는 bi-directional 터널이 중복되는 routing problem이 발생한다. 따라서 본 논문에서는 중첩된 이동네트워크가 계층적 구조를 가지는 것을 이용하여, 최상위 MR 이 지역 HA 역할을 수행하게 항으로써, 중첩된 이동네트워크내의 노드들을 위한 경로최적화와 마이크로 이동성을 동시에 지원할 수 잇도록 한다.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.131-139
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• 2016

This paper shows the series power device in the massive roof-top PVs and domestic loads. D-UPFC as the series power device controls the distribution voltage during voltage rise (or fall) condition. D-UPFC consists of the bi-directional ac-ac converter and the transformer. In order to verify the D-UPFC voltage control, the distribution model is used in the case study. D-UPFC enables the voltage control in the distribution voltage range. Dynamic voltage control from voltage rise and voltage fall conditions is performed. Scaled-down experimental test of the D-UPFC is verified the voltage control and it is well performed without high voltage spikes in the inductive load.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.345-348
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• 2007

This research aimed at developing a technique for estimating the tree height using BRF (Bi-directional Reflectance Factor) through the clarification of the relation between shape of the tree crown and the tree height and the relations between the shape of the tree crown and BRF. This paper, reports the results of analyses of data acquired by field measurements done to clarify relation between crown shape and tree height.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.526-532
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• 2009

말뚝의 정재하시험을 통하여 항복하중 및 극한하중을 판별하는 다양한 방법이 제안되어 왔다. 말뚝의 지지력은 주면마찰력과 선단지지력의 합으로 나타내어 왔으나 말뚝 재하시험을 통한 항복 하중 및 극한하중의 판별법은 대체로 총 침하량에 대해 판별하거나 재하하중-침하 그래프로부터 산정되는 경우가 대표적이다. 본 연구에서는 현장 대구경 양방향 재하시험 결과를 활용하여 말뚝의 주면부와 선단부로 나누어 항복하중을 판별할 수 있는 방법을 제안하고자 한다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.474-479
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• 2008

The purpose of this paper is to estimate the fire safety in tunnels with bi-directional and/or congested unidirectional traffic where there may be people on both sides of the fire. Therefore, the spread and movement of smoke are simulated by Fire Dynamic Simulator code under different ventilation systems, longitudinal, semi-transverse, large port exhaust system. And as quantitative risk index, FED (Fractional Effective Dose) for each ventilation system are calculated and compared by existed code developed previous research.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.1-6
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• 2011

In this paper, search-efficient Bi-directional-Chord(B-Chord) is proposed in P2P (peer-to-Peer) overlay network. Chord is the most popular P2P Look-up protocol. However, it applied to the mobile environment, the search success rate become lower and the request delay time increases. That is big problem. Thus, by improving the existing Chord, in this paper proposed B-Chord reduces the request delay time to in a mobile environment. Proposed B-Chord have the two Finger table and can search by selecting Finger table depending on the value of Key. By use these bi-directional, it can reduce the number of nodes Hop and search delay time. Thus, As a result, it will be able to increase the search success rate in a mobile environment.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.4
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• pp.189-196
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• 2020

In this study, two full-scale gravity load-designed reinforced concrete corner beam-column joints were tested by being subjected to uniand bi-directional cyclic lateral loading. The test variable was loading type: uni- or bi-directional loading. To investigate the effect of the loading type on the cyclic behavior of joint specimens, damage progression, force-deformation relation, contribution of joint deformation to total drift, joint stress-strain response, and cumulative energy dissipation were investigated. The test data suggest that bidirectional loading can amplify damage accumulation in the joint region.