• 한국컴퓨터정보학회논문지
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• 제21권5호
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• pp.49-56
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• 2016

Increasing Internet traffic and forwarding table size need high performance IP address lookup engine which is a crucial function of routers. For finding the longest matching prefix, trie-based or its variant schemes have been widely researched in software-based IP lookup. As a software router, we enhance the IP address lookup engine using GPU which is a device widely used in high performance applications. We propose a data structure for multibit trie to exploit GPU hardware efficiently. Also, we devise a novel scheme that the root subtrie is loaded on Shared Memory which is specialized for fast access in GPU. Since the root subtrie is accessed on every IP address lookup, its fast access improves the lookup performance. By means of the performance evaluation, our implemented GPU-based lookup engine shows 17~23 times better performance than CPU-based engine. Also, the fast access technique for the root subtrie gives 10% more improvement.

• 한국정보통신학회논문지
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• 제17권12호
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• pp.3030-3037
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• 2013

위성통신설비의 수명은 설비별 사용빈도와 운영환경에 따라 상이하나, 설비 개대체시 내용년수만을 고려하고 있는 실정이다. 따라서, 설비의 성능분석을 통한 상태평가 및 의사결정에 따른 과학적 근거를 기초로 한 경제적인 자산관리가 필요하다. 본 연구에서는 K-water에서 사용하고 있는 위성통신설비에 대하여 물리적 평가, 성능분석 평가, 경제성 평가, 내용년수 평가를 통한 과학적인 상태평가표를 제안하였으며, 이를 통한 합리적인 개대체 방안을 수립하였다.

• 한국조경학회지
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• 제51권2호
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• pp.120-130
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• 2023

본 연구의 목적은 근린공원 서비스의 질적 수준을 평가하기 위한 공원성능평가도구(Park Performance Assessment Tool, PPAT)를 개발하는 것이다. 공원성능평가도구(PPAT) 개발 과정은 다음과 같다. 첫째, 국내·외 공원성능평가도구(PPAT) 관련 사례 분석을 통해 평가항목 풀을 구성하였다. 둘째, 전문가 자문회의 및 시범 평가를 통해 국내 공원 여건에 적합한 평가항목으로 정제하였다. 셋째, 시범 평가를 통한 공원성능평가도구(PPAT)의 신뢰도를 검증하였다. 넷째, 전문가 설문조사와 AHP 분석을 통해 평가항목별 가중치를 도출하였다. 다섯째, 공원성능평가도구(PPAT) 평가표와 평가 가이드라인을 작성하였다. 공원성능평가도구(PPAT)를 인천광역시 부평구의 22개 근린공원에 적용하여 물리적 공간 환경의 품질을 평가하였다. 평가 결과, 공원 서비스 개선이 필요한 열악한 질의 근린공원이 다수 발견되었다. 공원성능평가도구(PPAT)는 공원녹지기본계획 수립, 공원 정비사업 우선순위와 사업추진방식 선정, 우수 공원 인증 등에 활용할 수 있을 것으로 기대한다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.110-117
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• 2005

This paper deals the shaking table tests with 1/100 scaled model followed by Scott & Iai(1989)'s similitude law for OO dam main desging section to understand nonlinear behavior characteristics of concrete dam body by earthquake wave. As earthquake wave, Hachinohe and Elcentro waves were used and acceleration and displacements are measured to analyze behaviors of dam body. For ground maximum acceleration range ($0.3^{\sim}0.9g$), the results showed linear behavior regardless of ground maximum acceleration and secured safety of structure. To analyze the behavior of dam after tension cracking, 3cm-notch was placed at the critical section of over-flowing section. As results of applying Hachinohe wave(0.8g), Even though tension cracks were formed at over-flowing section by Hachinohe wave(0.8g), it showed that the dam is stable for supporting upper stream part of water tank of dam.

• 대한인간공학회지
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• 제19권3호
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• pp.61-75
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• 2000

To enhance web site's usability, it has been suggested that the depth of tree structured menus should be minimized. In this research, experimental results are reported to quantitatively compare the methods currently used for reducing the depth of menus in web sites. 25 popular web sites were selected and their menu types were categorized into four types: top menu, drop-down menu, boolean menu, and table of contents. The four types of menu were then sub-categorized into 15 different types according to their sub-menu type, existence of menu colors, and the event occurring after mouse activation. Performance tests and subjective evaluation were carried out. The results showed that there were no significant differences in terms of response time among the 15 menu types, while table of contents and drop-down in which the first and second level of menus were visible induced the least number of errors. In the subjective test, the top-menu structure with colors and presentation of its sub-menu without clicking mouse were preferred.

• 한국지반공학회논문집
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• 제16권5호
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• pp.75-81
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• 2000

본 연구에서는 진동대 시험을 실시하여 지진동에 대한 일반 안벽 구조물과 내진 보강된 안벽 구조물의 동적거동을 분석하고 내진보강기법의 성능을 평가하였다. 진동대 시험은 기초지반이 조밀한 경우와 느슨한 경우, 자갈 뒤채움재를 설치한 경우 그리고 내진대책공법으로 경량재 치환공법과 모래다짐말뚝 공법을 적용한 경우 등 총 5가지 시험단면에 대하여 실시하였다. 과잉간극수압, 가속도 반응 그리고 지반의 변형양상을 분석한 결과, 기초지반과 뒤채움 지반의 연약화가 안벽 구조물의 동적거동에 큰 영향을 미치며, 경량재 치환공법과 모래다짐말뚝공법이 안벽 구조물의 내진성능을 향상시키는에 효과적인 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.305-308
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• 2006

In this paper, the seismic performance of SRC piers for near fault motions was evaluated by shaking table tests on small scale models. Dead load of the superstructures was simulated by axial prestress at the center of the column section. A mass frame linked with steel bars was fabricated to include the effect of superstructure mass. Friction of the mass frame when it moves was minimized by special details and it was proved before tests. Five pier models with 400mm diameter were tested by increasing the acceleration of the near fault motion. Test results were discussed and compared with previous quasi-static tests.

• 농업과학연구
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• 제50권3호
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• pp.469-484
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• 2023

In this study, three types of structures-stepped gabion retaining walls, vertical gabion retaining walls, and parapets-were installed on the dam floor crest to prevent the overflow of deteriorative homogeneous reservoirs. The acceleration response, displacement behavior, and pore water pressure ratio behavior were compared and evaluated using shaking-table model tests. The experimental conditions were set to 0.154 g in consideration of the domestic standard and the seismic acceleration range according to the magnitude of the earthquake, and the input waveform was applied with Pohang, Gongen, and artificial earthquake waves. The acceleration response according to the design ground acceleration increased as the height of the embankment increased, and the observed value were larger in the range of 1.1 to 2.1 times the input acceleration for all structures. The horizontal and vertical displacements exhibited maximum values on the upstream slope, and the embankment was evaluated as stable and included within the allowable range for all waveforms. The settlement ratio considering the similarity law exhibited the least change in the case of the parapet structure. The amplification ratio was 1.1 to 1.5 times in all structures, with the largest observed in the dam crest. The maximum excess pore water pressure ratio was in the range of 0.010 - 0.021, and the liquefaction evaluation standard was within 1.0, which was considered very stable.

• 한국태양에너지학회 논문집
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• 제24권2호
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• pp.51-62
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• 2004

Architects may evaluate building models to see how a building will shadow itself and its neighbors at various times. A heliodon, a tilt-table which is a machine that imitates the rotation and orbit of the Earth, helps architects wanting to analyze patterns of shadow patch, passive solar heating options, site solar panels, or control solar heat gain. The heliodon swivels in three directions for setting latitude, season, and time of day. Using the device, an architect first clamps a model to the tabletop, then turns the table to the coordinates of interest. Usually, the winter and summer solstices receive strong attention, for they represent extreme cases, A more recent installation at a university adds to its heliodon a set of lamps to recreate the illumination level and more accurate patterns of shadow patch. The table holds the building model at various angles to a spotlight, which mounts in the pole. The set of scale model measurement describes the validity of various electric lamps as an artificial sun to approximate the sun's parallel rays, helping designers to distinguish between illuminated areas in and around a building and those regions falling in the shadows.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.213-220
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• 2010

This study presents a numerical simulation model of vertical ground heat exchangers, considering unsaturated hydro static ground conditions induced by the ground water table fluctuation. Heat transfer in ground and grout is modeled by a 3-D FEM transient conductive heat transfer model, where heat transfer between circulating fluid and heat exchanging pipe is treated as 1-D quasi steady state forced convective elements. To take into account the unsaturated ground condition, soil thermal conductivity and heat capacity which are dependent on the matric suction are applied to ground elements. Parametric studies considering various ground water table conditions are conducted to investigate the influence of unsaturated hydro static ground condition on the mean heat exchange rate of ground heat exchanger. Simulation results considering water table fluctuation show 60~100% of mean heat exchange rate for a saturated soil condition and 125~208% of that for a dry soil condition. Thus consideration of unsaturated soil condition is substantially recommended for more accurate design and performance evaluation for ground heat exchangers.