• Proceedings of the KWS Conference
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• 2009.11a
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• pp.7-7
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• 2009

TIG 용접에서는 후판 용접의 경우 용입의 한계 때문에 깊고 넓은 그루브 가공을 하여 다층 용접을 한다. 이 때, 그루브를 채우는 용착금속에 의한 응고 수축과 과대한 입열로 인한 변형이 문제시 되고 있다. 변형을 줄이기 위해서는 용착금속의 양과 입열량을 줄여야 한다. 이러한 문제를 해결하기 위해 그루브의 루트패이스를 두껍게 하고 그루브각을 줄여서 용착량을 줄인다. 이때, 좁은 그루브에서 두꺼운 루트패이스를 완전 용입할 수 있는 용접 프로세스가 필요하다. 비드가 좁고 깊은 용입 특성을 가지는 Plasma welding(PAW) 경우에는 좁은 그루브 속에 토치가 접근하기 어려워 적용하기 어렵다. 따라서 접근성이 용이한 TIG 용접에서 높은 용입형상비를 가지는 용접공정 개발이 필요하다. 선행연구로 높은 용입 형상비를 가지는 Active flux Tungsten Inert Gas(ATIG) 용접이 연구되었다. ATIG의 용입 증가 메커니즘으로는 Marangoni effect, 음이온들로 인한 아크 수축 효과, 절연 플럭스에 의한 아크 수축효과 등으로 알려져 있다. 또한 선행연구에서 ATIG에서 Ar가스에 He 또는 $H_2$ 가스를 첨가하면 용입이 더욱 증가하는 것을 확인하였다. 본 연구에서는 A-TIG에 He 가스를 적용하고 아크길이 0.5mm, 1.0mm, 2.0mm와 전극 선단각 30도, 60도, 90도에 따른 용입 형상비와 변형량을 검토하기 위해 실험을 하였다. 실험 결과는 아크길이가 감소할수록 전극 선단각이 증가할수록 용입 형상비는 증가하였고, 변형량은 감소하였다.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.813-823
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• 2011

This study is to suggest the facial animation methodology for that 3D character animators can use CGS system effectively during on their stage which they create ideas and use repeating a process of facial animation, it has suggested the CGS(Character Generation System) that is a creative idea generation methodology identified and complemented the problem of the existing computerized idea generation, in addition, this research being extended on the article vol.13, no.7, "CGS System based on Three-Dimensional Character Modeling II (Part2: About Digital Process)," on Korea Multimedia Society in July 2010 issue, Through the preceding study on 3D character facial expression according to character's feelings as an anatomical structure and the case study on character expressions of theatrical animation, this study is expected to have effectives as one method for maximization of facial animation and idea generation ability.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.475-479
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• 2005

Such changes that the digital paradigm brought propels a change of the value system itself in the existing society so that a way of thinking that differentiates oneself from others is getting much stronger. As public interests are higher in the image production on the internet, such authoring environments as development of related technologies, expansibility of information, and systematization of available information continue to change. Therefore, a variety of unique image presentations that fit to the changed environments are necessary and an expression method is indispensable for such image production. It suggests digital image application methods and examples that contain not just simple image distortion or variation but intrinsic significance. It is believed that it will be of good use to produce a variety of unique and innate digital images in the end.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.6
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• pp.1-8
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• 2005

The calculation of parameters of a process model is modified to find better sliding mode controller for a process. A design method by Camacho has such problems as chattering and overshoot due to the Taylor the approximation errors for the time delay term of the first order model. In this paper, a new design technique for a sliding mode controller is proposed by introducing the modified Pade approximation considering the weight factor. With the proposed method, the process response can be directly used to estimate the system parameters without any numerical processing.

• Management & Information Systems Review
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• v.37 no.1
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• pp.19-40
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• 2018

The purpose of this study is to analyze the effects of a firm's dynamic capabilities measured by sensing, seizing, transforming, coordinating, and learning capabilities on its competitive capabilities, such as product quality, process flexibility, delivery speed, and low cost. The relationship among dynamic capabilities, competitive capabilities, and export firm performance is set up as a research model based on empirical studies related to the existing dynamic capability perspective and competitive capabilities. To test this research model, this study collected 102 samples of data using a questionnaire survey on both manufacturing and exporting firms. The partial least squares method is used and the following results are derived from an empirical analysis. First, dynamic capabilities have a positive effect on competitive capabilities, such as product quality, process flexibility, delivery speed, and low cost. Second, product quality and process flexibility have a positive effect on export firm performance. Third, unlike previous research results, this study finds that the competitive capabilities of a firm in the areas of delivery speed and low cost do not significantly affect its performance. These findings provide meaningful implications for export venture firms that need to acquire and maintain competitive advantage in a rapidly changing environment.

• The Journal of the Korea Contents Association
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• v.6 no.4
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• pp.89-97
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• 2006

Such changes that the digital paradigm brought propels a change of the value system itself in the existing society so that a way of thinking that differentiates oneself from others is getting much stronger. As public interests are higher in the image production on the internet, such authoring environments as development of related technologies, expansibility of information, and systematization of available information continue to change. Therefore, a variety of unique image presentations that fit to the changed environments are necessary and an expression method is indispensable for such image production. This study focuses on digital image creating in which a synectics method is applied. It suggests digital image application methods and examples that contain not just simple image distortion or variation but intrinsic significance. It is believed that it will be of good use to produce a variety of unique and innate digital images in the end.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.12
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• pp.692-703
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• 2004

Communication induced checkpointing (CIC) is one of the checkpointing techniques to provide fault tolerance for distributed systems. Independent checkpoints that each distributed process produces without coordination are likely to be useless. Useless checkpoints, which cannot belong to any consistent global checkpoint sets, induce nondeterminant rollback. To prevent the useless checkpoints, CIC forces processes to take additional checkpoints at proper moment. The number of those forced checkpoints is the main source of failure-free overhead in CIC. In this paper, we present two new CIC protocols which satisfy 'No Z-Cycle (NZC)'property. The proposed protocols reduce the number of forced checkpoints compared to the existing protocols with the drawback of the increase in message delay. Our simulation results with the synthetic data show that the proposed protocols have lower failure-free overhead than the existing protocols. Additionally, we show that the classical 'index-based checkpointing' protocols are inefficient in constructing the consistent global cut in distributed executions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.129-134
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• 2013

Previous research is focus on testcase generation automation using message sequence diagram based on metamodel. but that research is not enough for testcase genaeration automation using state diagram based metamodel. so in this paper is adopt Model Driven Architecture (MDA) mechanism for using metamodel and model transformation. and we suggest testcase automation mechanism using state diagram in UML. we will decrease cost of embedded software design and testcase genaration and increase quality of embedded software using metamodel mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1244-1255
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• 1994

The wireless-LAN(Local Area Network), which is emerged as a solution to cable problem and increasing requirement for communication network, has a several problem when it transmit information MAN protocol by used wired-LAN`s MAC protocol. Media Access protocol in Wireless-LAN has great effect on system performance and much studies are processing now. The PRMA(Packet Reservation Multiple Aeecss) of reservation method has a disadvantage that the system performance was degraded become of delay time in the reservation step as a resulting of collision. In this paper, using the TDD(Time Division Duplex) method amd modified PRMA method wireless-LAN modelled to overcome disadvantage, that id delay time due to collision in reservation step. The performance evaluation fo the model was done using M/M/1//M process model and this was simulation using SLAM.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.111-121
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• 2007

The paper presents a reliability-based method that can capture the impact of uncertainty of seismic loadings. The proposed method incorporates probabilistic concepts into the classical limit equilibrium and the Newmark-type deformation techniques. The risk of damage is then computed by Monte Carlo simulation. Random process and RMS hazard method are introduced to produce seismic motions and also to use them in the seismic slope analyses. The geotechnical variability and sampling errors are also considered. The results of reliability analyses indicate that in a highly seismically active region, characterization of earthquake hazard is the more critical factor, and characterization of soil properties has a relatively small effect on the computed risk of slope failure and excessive slope deformations. The results can be applicable to both circular and non-circular slip surface failure modes.