• Progress in Medical Physics
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• v.18 no.2
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• pp.73-80
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• 2007

Fruitful findings have been produced from five out of sixty cells which were obtained from each 63 individual Aplisia caught at the Jeju coast. Spiking patterns of three out of five cells, such as relaxation oscillator, bursting within a short time of the inter-burst interval, chaotic bursting, period doubling sequences, bursting with long trains of action potentials separated by short silent periods, regular repeated beating or elliptic bursting, and silent states had been changed in order as the temperature was lowered to $10^{\circ}C\;from\;32^{\circ}C$. In the intervals of every about 40 minutes repeated ups and downs of temperature produced similar firing patterns at the allowable temperature ranges. The other two cells showed difference from these. The amplitudes of the action potentials of the two cells will not be highly decreased in 24 hours. Average spike frequencies, the inter-burst interval, peak to peak spike amplitude of action potentials, minimum potential values are compared and analyzed by using the computer programme. The spike frequencies according to temperature show the distribution of bell type, with maximal spike frequencies at intermediate temperatures and minimal ones at either end. The most common pattern consist of high spike frequency during failing and low one during rising temperatures.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.135-136
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• 2022

메타버스란 가공, 추상을 의미하는 메타(Meta)와 현실을 의미하는 유니버스(Unvierse)의 합성어이며 가상의 3차원을 뜻한다. 현재 메타버스는 4차 산업혁명의 중요 트렌드로 지목되어지고 있으며 다양한 기업들의 투자 또한 지속적으로 증가하는 추세이다. 이중 게임은 메타버스에서 가장 많은 비중을 차지하고 있으나 아직까지 메타버스 게임의 신뢰도가 높지 않으며 현재 출시되었거나 앞으로 출시될 게임들에 대한 적합한 테스트 기법이 필요한 실정이다. 이에 본 논문에서는 메타버스를 기반으로 하는 게임 테스팅에 강화학습 에이전트를 활용하는 방안에 대해 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.11B
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• pp.1948-1956
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• 2000

본 논문은 보드 레벨 테스팅 및 경계주사기법의 응용을 위한 테스트 버스 콘트롤러의 설계와 구현에 관해 다룬다. 테스트 버스 콘트롤러는 프로세서와 인터페이스를 통하여 IEEE 1149.1 테스트 버스를 제어하기 위한 칩이다. 최근 들어 IEEE 1149.1은 여러 분야에서 응용되어지고 있어서 다양한 응용분야에 적합한 테스트 버스 콘트롤러의 설계가 요구된다. 보드 레벨 테스팅을 위해서 SVF에 정의된 테스트를 수행할 수 있어야 하며, System-on-a-Chip (SoC) 설계 방식에서 내장되어지기 위해서는 작은 칩 크기와 높은 고장 검출률을 가져야 한다. 본 논문에서 구현된 칩은 기존의 테스트 장비에서 널리 쓰이는 SVF에 정의된 테스트를 모두 지원하며, 12k 게이트 정도의 크기를 가진다. 또한 독립적인 칩으로 쓰일 경우는 테스트 버스 콘트롤러가 버스 슬래이브로 쓰일 수 있으므로 IEEE 1149.1 테스트 회로를 가지도록 설계하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1125-1146
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• 2018

Segment lining applied to the TBM tunnel is mainly made of concrete, and it requires sufficient structural capacity to resist loads received during the construction and also after the completion. When segment lining is design to the Limit State Design, both Ultimate Limit State (ULS) and Service Limit State (SLS) should be met for the possible load cases that covers both permanent and temporary load cases - such as load applied by TBM. When design segment lining, it is important to check structural capacity at the joints as both temporary and permanent loads are always transferred through the segment joints, and sometimes the load applied to the joint is high enough to damage the segment - so called bursting failure. According to the various design guides from UK (PAS 8810, 2016), compression stress at the joint surface can generate bursting failure of the segment. This is normally from the TBM's jacking force applied at the circumferential joint, and the lining's hoop thrust generated from the permanent loads applied at the radial joint. Therefore, precast concrete segment lining's joints shall be designed to have sufficient structural capacity to resist bursting stresses generated by the TBM's jacking force and by the hoop thrust. In this study, bursting stress at the segment joints are calculated, and the joint's structural capacity was assessed using Leonhardt (1964) and FEM analysis for three different design cases. For those three analysis cases, hoop thrust at the radial joint was calculated with the application of the most widely used limit state design codes Eurocode and AASHTO LRFD (2017). For the circumferential joints bursting design, an assumed TBM jack force was used with considering of the construction tolerance of the segments and the eccentricity of the jack's position. The analysis results show reinforcement is needed as joint bursting stresses exceeds the allowable tensile strength of concrete. This highlights that joint bursting check shall be considered as a mandatory design item in the limit state design of the segment lining.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.409-414
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• 2008

In mobile ad hoc networks, most of on demand routing protocols such as DSR and AODV do not deal with traffic load during the route discovery procedure. To solve the congestion and achieve load balancing, many protocols have been proposed. However, the existing load balancing schemes has only considered avoiding the congested route in the route discovery procedure or finding an alternative route path during a communication session. To mitigate this problem, we have proposed a new scheme which considers the packet bursting mechanism in congested nodes. The proposed packet bursting scheme, which is originally introduced in IEEE 802.11e QoS specification, is to transmit multiple packets right after channel acquisition. Thus, congested nodes can forward buffered packets promptly and minimize bottleneck situation. Each node begins to transmit packets in normal mode whenever its congested status is dissolved. We also propose two threshold values to define exact overloaded status adaptively; one is interface queue length and the other is buffer occupancy time. Through an experimental simulation study, we have compared and contrasted our protocol with normal on demand routing protocols and showed that the proposed scheme is more efficient and effective especially when network traffic is heavily loaded.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.299-300
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• 2023

최근 인공지능의 현실화와 더불어 프로그래밍 언어인 Python의 독주가 한창이다. 그렇다면 과연 메타버스 시대가 현실화 된다면 어떤 프로그래밍 언어가 대세가 될 것인가. 현재 메타버스 플랫폼인 로블록스에서 사용되고 있는 루아스크립트, 제페토 월드에서 사용되고 있는 Typescript에서 착안해서 미래의 메타버스 개발에 공용으로 사용될 효율적인 언어를 살펴보았다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06a
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• pp.165-166
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• 2007

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2253-2261
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• 2002

Recently the hydroforming technology has drawn a lot of attention because of its capability to produce high quality and light weight parts. In the present study, the tube expansion - one of the simplest hydroforming processes, has been investigated in order to understand fundamental phenomena such as deformation characteristics and effect of process parameters. As a result, the most important process parameters, which determine the state of stress at the expanded zone, were found to be pressure and die displacement. If the stress becomes equi-axial tension at the zone, necking occurs at some distance from the weld line and develops into a crack along the axial direction. Some aspects of mechanical property measurements as well as distributions of hardness and microstructure are also discussed in this paper.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.733-734
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• 2008

In wireless multihop networks, most of on demand routing protocols suffer from performance degradation due to high mobility and channel errors. This problem is more serious as routing path increases. In this paper, we propose a new scheme which can improve network throughput by using distance adaptive packet bursting. The bursting mechanism is to transmit multiple packets after channel acquisition. Through the simulation, we show that our scheme is more efficient than existing methods.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.52-60
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• 2020

When a bubble reaches a free surface, a bursting of the bubble produces a high speed jet. Despite its practical importance, significant effort has been devoted to investigate a bursting jet by a single bubble near a free surface. In the present study, we perform numerical simulations of bubbles in a tandem arrangement at Bo=0.05. The configuration of the tandem bubbles is systematically varied by changing a radius of a following bubble (RF) and the gap distance between two bubbles (L). Compared to a single bubble case, we show that the bursting bubble in the tandem arrangement accelerates, and the jet velocity increases. Moreover, we find that a critical gap distance at which the jet velocity unexpectedly changes exists in the tandem case.