• 센서학회지
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• 제18권4호
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• pp.322-326
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• 2009

To estimate the measurement uncertainty for industrial platinum resistance thermometers(IPRTs) made with 3-wire connection, the immersion temperature profile was investigated using a liquid bath. Two types of IPRTs having lead wires made of silver and nickel were constructed and the immersion profiles were measured at temperatures from -50 $^{\circ}C$ to 250 $^{\circ}C$ using 3-wire and 4-wire method. As immersion depth and temperature increased, the resistances measured by 3-wire method increased linearly but not for 4-wire method. To calibrate a 3-wire IPRT, the immersion effect must be accounted for. We propose a linear equation to assess correctly the measurement uncertainty.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1562-1571
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• 2005

The use of geogrid for SRW systems and bridge abutment has increased rapidly over the past 10 years in Korea. The concept of segmental retaining walls and reinforced soil is very old and for example The Ziggurats of Babylonia(i.e. Tower of Babel) were built some 2,500 to 3,000 years ago using soil reinforcing methods very similar to those described in current design. Modern SRW(Semental Retaining Wall) units were introduced in 1960's as concrete crib retaining wall systems. In this paper, the friction properties between segmental concrete units and geogrid are investigated by performing various tests.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 춘계 종합학술대회 논문집
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• pp.35-39
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• 2004

본 논문에서는 채팅, 화상 채팅에 대한 실태분석 및 이를 기술적으로 해결하기 위한 전체 시스템중 채팅, 화상 채팅에 대한 전반적 실태 분석을 행하고자 한다. 이를 위해 대표적인 채팅, 화상 채팅 사이트에 대한 메뉴 분석, 접속자수 조사, 연령별, 성별 접속자수 분석 등을 행하였으며 설문 조사를 통해 각종 채팅과 화상 채팅에 대한 문제점 분석을 행하고자 한다. 끝으로 그 해결 방안에 대해 정리하고자 한다.

• 토지주택연구
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• 제3권2호
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• pp.169-175
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• 2012

최근, 지열 냉난방 시스템의 초기 공사비를 절감하기 위해 연구되고 있는 에너지 파일의 열교환량을 산정하기 위해 2종류(부속연결형, 슬링키형)의 현장타설말뚝형(PRD, 시공심도 4.5m, 직경 1,200mm) 에너지 파일을 시험시공하고 수치 시뮬레이션에 의해 효율을 상호 비교하였다. 상호 비교결과에 의하면 지중 교환량은 운전시작과 함께 채열에 의한 지중온도의 저하에 의해 점점 감소하였고 부속연결형의 평균 열원수의 온도차는 난방운전에서 $0.37^{\circ}C$, 냉방운전에서 $0.34^{\circ}C$로 나타났다. 또, 부속연결형의 난방운전시 열교환량 231.4W/m보다 냉방운전의 방열량은 252.2W/m로서 9% 높았고 슬링키형은 난방 기간 평균 열교환량이 168.0W/m로 부속연결형에 비해 약 27% 낮은 열교환량을 얻었다.

• 도시과학
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• 제7권2호
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• pp.29-36
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• 2018

The demand for reinforcement in accordance with remodeling, seismic retrofit, and change of use of the existing structure is increasing. Originally, shear wall new and extension method has been adopted a lot as seismic retrofit methods. Recently, dry seismic retrofit method that uses structural steel is mostly adopted in order to minimize spatiotemporal aspect and underpinning that occurs when a construct shear wall. We redesigned the form of old and new concrete joint high-shear ring anchor that was developed according to recent reinforcement method and determined construction method. Shear tests were performed on High-Shear Ring Anchor for steel-concrete connection. Comparison with 4 tests shows that the average of test-to-prediction ratios is 1.01.

• 산업공학
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• 제9권3호
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• pp.168-179
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• 1996

Automatic repeated recalling from individual computing equipments such as PC and workstations, to access ATM networks may result in call overload to networks. Call overload causes to waste network resources and fail to meet user call processing QoS requirements. We evaluate two call connection request methods: the back-off recall method(BRM) which makes recall with random waiting time after rejection, and the direct recall method(DRM) which repeats call connection request whenever call request is rejected. We evaluate their performances by simulation and it shows that as the total number of attached terminals to each access node increases, BRM performs better than DRM in terms of the call acceptance level and effective network bandwidth utilization.

• ETRI Journal
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• 제45권3호
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• pp.433-447
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• 2023

Critical issues such as connection congestion, long transmission delay, and packet loss become even worse during epidemic, disaster, and so on. In this study, a link load balancing method is proposed to address these issues on the data plane, a plane of the software-defined network (SDN) architecture. These problems are NP-complete, so a meta-heuristic approach, discrete particle swarm optimization, is used with a novel hybrid cost function. The superiority of the proposed method over existing methods in the literature is that it provides link and switch load balancing simultaneously. The goal is to choose a path that minimizes the connection load between the source and destination in multipath SDNs. Furthermore, the proposed work is dynamic, so selected paths are regularly updated. Simulation results prove that with the proposed method, streams reach the target with minimum time, no loss, low power consumption, and low memory usage.

• Journal of applied mathematics & informatics
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• 제7권1호
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• pp.139-159
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• 2000

In this manuscript we study perturbed Newton-like methods for the solution of nonlinear operator equations in a Banach space and their discretized versions in connection with the mesh independence principle. This principle asserts that the behavior of the discretized process is asymptotically the same as that for the original iteration and consequently, the number of steps required by the two processes to converge to within a given tolerance is essentially the same. So far this result has been proved by others using Newton's method for certain classes of boundary value problems and even more generally by considering a Lipschitz uniform discretization. In some of our earlierpapers we extend these results to include Newton-like methods under more general conditions. However, all previous results assume that the iterates can be computed exactly. This is mot true in general. That in why we use perturbed Newton-like methods and even more general conditions. Our results, on the one hand, extend, and on the other hand, make more practical and applicable all previous results.

• 대한치과보철학회지
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• 제42권2호
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• pp.192-209
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• 2004

Purpose : The purpose of this study was to evaluate the machining accuracy and consistency of implant/abutment/screw combination or internal connection type. Material and methods: In this study, each two randomly selected internal implant fixtures from ITI, 3i, Avana, Bicon, Friadent, Astra, and Paragon system were used. Each abutment was connected to the implant with 32Ncm torque value using a digital torque controller or tapping. All samples were cross-sectioned with grinder-polisher unit (Omnilap 2000 SBT Inc) after embeded in liquid unsaturated polyester (Epovia, Cray Valley Inc). Then optical microscopic and scanning electron microscopic(SEM) evaluations of the implant-abutment interfaces were conducted to assess quality of fit between the mating components. Results : 1) Generally, the geometry of the internal connection system provided for a precision fit of the implant/abutment into interface. 2) The most precision fit of the implant/abutment interface was provided in the case of Bicon System which has not screw. 3) The fit of the implant/abutment interface was usually good in the case of ITI, 3I and Avana system and the amount of fit of the implant/abutment interface was similar to each other. 4) The fit of the implant/abutment interface was usually good in the case of Friadent, Astra and Paragon system. The case of Astra system with the inclined contacting surface had the most Intimate contact among them. 5) Amount of intimate contact in the abutment screw thread to the mating fixture was larger in assembly with two-piece type which is separated screw from abutment such as Friadent, Astra and Paragon system than in that with one-piece type which is not seperated screw from abutment such as ITI, 3I and Avana system. 6) Amount of contact in the screw and the screw seat of abutment was larger in assembly of Friadent system than in asembly of Astra system of Paragon system. Conclusion: Although a little variation in machining accuracy and consistency was noted in the samples, important features of all internal connection systems were the deep, internal implant-abutment connections which provides intimate contact with the implant walls to resist micro-movement, resulting in a strong stable interface. From the results of this study, further research of the stress distribution according to the design of internal connection system will be required.

• 대한치과보철학회지
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• 제50권2호
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• pp.119-127
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• 2012

연구 목적: 본 연구는 3차원 유한요소분석을 통해 특징적인 내부연결구조를 갖는5종의 임플란트의 고정체와 지대주의 연결방식에 따른 응력분산을 알아보고자 하였다. 연구 재료 및 방법: 본 실험을 위한 유한요소모델은 하악 제1대구치부에 임플란트가 식립되고 상부구조물로 3형 금합금을 사용하는 것으로 가정하였다. 응력분산은 200 N의 하중이 교합면의 중심, 중심에 1.5 mm 외측, 중심에서 3.0 mm 외측에 수직으로 가해지고 임플란트의 장축과 $30^{\circ}$의 각도로 경사하중이 가해지도록 하여 분석하였다. 유한요소모델에 대한 해석작업은 3G.Author (PlassoTech, California, USA)를 사용하여 이뤄졌다. 결과: 경사가 없는 내부계단 구조를 가지는 DAS tech의 임플란트의 경우, 내부연결구조를 갖는 다른 임플란트에 더 유리한 응력분산을 보였다. 하중이 임플란트 고정체의 외형선 이내에 가해지는 경우와 비교하여 외형선 바깥이나 경사력으로 전해지는 경우 더 높은 응력을 보였으며 하중조건과 관계없이 임플란트 고정체보다는 지대주에 더 큰 응력이 집중되었다. 결론: 교합력이 가해졌을 때 응력분산은 임플란트의 연결부의 형태와 하중이 가해지는 위치에 따라 달라졌으며 내부계단 구조를 가지는 DAS tech의 임플란트를 사용한 경우와 고정체의 외형선 이내에 하중이 가해졌을 경우에 더 유리한 응력분산을 보였다.