알고리즘 수준에서의 IDCT 설계

이원표(Lee, Won Pyo),송승완(Song, Seung Wan),조양기(Cho, Yang Ki),김희석(Kim, Hi Seok) 한국통신학회 2004 한국통신학회 학술대회논문집 Vol.2004 No.11

기존 데이터센터의 구역단위 에너지 효율평가 방법 및 PUE 기반 M&V 베이스라인 모델 개발

조진균(Jinkyun Cho),홍원표(Won-Pyo Hong) 대한설비공학회 2020 설비공학 논문집 Vol.32 No.2

Data centers usually operate 24/7 year round and are very energy intensive. A data center sometimes uses up to 50 times more energy than a typical office building. High energy consumption can be attributed primarily to the IT demands and cooling equipment, power distribution. M&V (Measurement and Verification) is practical for all building types. An accurate determination of the energy baseline provides valuable feedback on the ECMs (energy conservation measures). As an alternative to the existing baseline method for normal buildings, we developed an energy baseline model for the M&V based on prediction models with the PUE index. This paper specifies a methodology of developing the PUE-based baseline for energy savings from the installation of mechanical and electrical systems in the data centers. In applying the PUE-based energy baseline, we derived the non-IT reference model and the baseline PUE for the IT server room area of large data centers in operation. This paper presents the standardized M&V approaches which target the minimizing of variations in quality across the analyses, and energy baseline requirements for data center projects and identifies energy prediction rules.

측방유동지반상 말뚝기초교대의 측방이동 평가

홍원표(Hong Won Pyo),이광우(Lee Kwang Wu),조삼덕(Cho Sam Deok),이재호(Lee Jae Ho) 대한토목학회 2007 대한토목학회논문집 C Vol.27 No.5

국내현장에서 수집된 43개 교대의 측방이동 실측자료에 대한 분석을 통해 말뚝기초교대의 측방이동을 간편하게 평가할 수 있는 방안을 제안한다. 실측된 교대측방변위를 고려하여 연약지반의 비배수전단강도와 교대배면에 작용하는 상재압의 관계를 분석한 결과, 교대 배변의 뒤채움으로 인한 상재압이 연약지반 비배수전단강도의 3배보다 작은 경우에는 실측된 교대변위가 국내 교대의 측방이동 허용치인 15㎜ 이내인 것으로 나타나, 교대 유지관리에 문제가 발생하지 않았다. 그러나 상재압이 연약지반 비배수전단강도의 3배~8.3배인 경우는, 교대변위가 15㎜~50㎜ 발생하는 것으로 나타났다. 따라서 이 경우 교대의 측방이동을 고려한 설계를 수행함으로써, 교대 측방변위를 허용치인 15㎜ 이하로 감소시켜야 한다. 특히 상재압이 비배수전단강도의 8.3배 이상이면, 50㎜ 이상의 심각한 교대변위가 발생할 수 있기 때문에, 적절한 교대 측방이동 대책공법이 강구되어야 하는 것으로 나타났다. 이러한 결과는 상재압과 비배수전단강도의 상관관계를 나타내는 사면지반의 안정수를 이용하면 측방유동지반상 말뚝기초교대의 측방이동 가능성을 간편하게 평가할 수 있음을 의미한다. 반면에 측방유동지수와 측방이동판정지수는 교대 실측변위 및 사면안전율과 상관성이 높지 않았다. 이는 경험지수만으로 교대의 측방이동 여부를 판정하는 것은 합리적이지 않음을 의미한다. 따라서 교대를 포함한 사면의 안정수가 3보다 크면, 교대기초말뚝의 사면안정 기여효과와 교대의 허용측방변위를 반영한 사면안정해석을 통해 교대 측방이동 여부를 면밀히 검토해야 한다. Field monitoring data for forty three piled bridge-abutments were investigated to suggest an evaluation method on lateral movement of the abutments. As the results of the investigation, if the surcharge pressure by backfills behind the piled-bridge abutment is less than 3 times the undrained shear strength of the soft grounds, the lateral displacement of the abutments was within 15 ㎜. Therefore, the abutment can be maintained without any problems because the abutment will move laterally within an allowable movement range. However, if the surcharge pressure is between 3 times and 8.3 times the undrained shear strength of the soft grounds, the abutments moved laterally between 15 ㎜ and 50 ㎜. In this case, the lateral displacement of the abutment should be considered on the design because the displacement may be considerable. Moreover, if the surcharge pressure behind the abutments is greater than 8.3 times the undrained shear strength of the soft grounds, the lateral displacement of the abutments could be more than 50 ㎜. In this case, a reasonable countermeasure should be applied to prevent excessive lateral displacement of the abutment, or the design of the abutment should be changed because the lateral movement is severe enough to severely damage the abutment. In tum, the stability number, which is the ratio of the surcharge pressure to the undrained shear strength can be used as the simplified empirical index to evaluate the possibility of lateral movement of abutments. However, both the lateral flow index and the lateral movement judgement index do not always show good relationship with not only the lateral displacement of the abutments but also the safety factor of slopes. Therefore, It is not always suitable to predict the lateral movement of abutments by using only conventional empirical indexes. These empirical indexes should be used together with the safety factor of slope with consideration of the allowable limit of the lateral displacement of the abutment.

8경간 연속화 프리스트레스 거더교의 시공 계측 및 분석

조성웅(Cho, Seong Woong),이원표(Lee, Won Pyo),임현태(Lim, Hyun Tai) 한국콘크리트학회 2001 한국콘크리트학회 학술대회 논문집 Vol.2001 No.11

대형할인매장에 적용된 마이크로가스터빈의 에너지 성능분석

홍원표(Hong Won-Pyo),김병수(Kim Byoung-Soo),조일식(Cho Yil-Sik) 한국태양에너지학회 2010 한국태양에너지학회 학술대회논문집 Vol.2010 No.11

The Aim of this study was to analyze Energy Performance of the Micro-gas turbine system installed in Large Scale Store. The process of this study is as follows: 1)The energy demand for electricity is estimated by surveying and sorting the consumption records for various equipment and devices in 2009. 2)Selected an large scale store for simulation model, Analyzed drawings(parts of Architecture, Building Services and Electric) and Characters of used energy for Building. 3)Analyzed energy performance of Micro-gas turbine system. Consequently, 1)The amount of total annual energy consumption are 18615.244㎿h/yr(286.4KWh/㎡yr), 3054㎿h/yr(47㎾h/㎡yr) for heating, 5660.09㎿h/yr(87.08㎾h/㎡yr) for cooling, 9900.47㎿h/yr(152.31KWh/㎡yr) for base energy(for hot water, lighting, ventilation, equipments, cooking and others), Base energy was the half of total used energy of large scale store. 2)If Micro-gas turbine system is installed, lighting energy can be decreased by about 62%, refrigerator and plug energy can be decreased by about 26.3%. 3)If the exhaust heat in Micro gas turbine system was recovered, the efficiency is risen up and total energy can be decreased by about 31.82%.

토목섬유 보강 성토지지말뚝의 설계사례 연구

홍원표(Won Pyo Hong),이재호(Jae Ho Lee),조삼덕(Sam-Deok Cho),이광우(Kwang Wu Lee) 한국토목섬유학회 2006 한국토목섬유학회 학술발표회 Vol.2006 No.4

Geosynthetic-reinforced and pile-supported (GRPS) systems have been used for several application fields in foreign countries. A series of researches have been performed to evaluate the effects of GRPS system in the internal field which is supposed damage due to lateral soil movement in soft ground. This paper describes a design case of GRPS system which is used as countermeasure against lateral movement of piled bridge abutment on soft ground. Useful design method for GRPS system is proposed through a design case

치과용 임플랜트에서 지대주 나사의 길이 및 반복 조임 횟수가 지대주 나사의 풀림에 미치는 영향

최진호,양재호,조원표,이재봉,Choi Jin-Ho,Yang Jae-Ho,Cho Won-Pyo,Lee Jai-Bong 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.4

Statement of problem: One of common problems associated with dental implant is the loosening of abutment screws that retain the implants. Purpose : This study was performed to investigate the influence of abutment screw length and repeated tightening on screw loosening in dental implant. Material and method: Forty nine Hexplants (13mm length, 4.3mm diameter, Ti grade IV, Warantec. Co. Ltd. Seongnam, Korea) and cementation type abutments(straight abutment) and abutment screws (0.4mm/pitch) were divided into 7 groups, depending on abutment screw length. Each implant and abutment was tightened to 30Ncm by torque controller(MGT50, MARK-10 Inc., USA) and the removal torque values were measured during 10 consecutive closure/opening trials. Results and Conclusion: The results of comparing the removal torque value are as follows : 1. There is no significant difference in the removal torque value between groups in 10 consecutive closure/opening trials (p = 0.97). 2. If the fractured abutment screw is engaged in longer than 2.425 thread length, there is no significant difference in the preload between the fractured abutment screw and the new abutment screw when both are equally tightened to 30 Ncm. 3. The removal torque value in the 1st trial(24.510 Ncm) was lower than that in the 2nd, 3rd, 4th, 5th, 6th, 7th trials and the removal torque value in the 2nd trials(25.551 Ncm) was maximum and was decreased in 1311owing trials. The removal torque value in the 1st trial was significantly lower than that in the 2nd, 3rd, 4th trials and was significantly higher than that in the 8th, 9th, l0th trials(p<0.05). 4. In the 2nd, 3rd, 4th, 5th, 6th, 7th trials, the abutment screw was mainly influenced by settling effect and the higher preload was obtained In the 8th, 9th, l0th trials, the abutment screw was mainly influenced by adhesive wear and the progressively lower preload was obtained.

편재하중 재하시 연약 점성토지반의 변형 특성에 관한 모형실험

이광우(Lee Kwang Wu),조삼덕(Cho Sam Deok),홍원표(Hong Won Pyo) 대한토목학회 2008 대한토목학회 학술대회 Vol.2008 No.10

성토하부 연약지반의 측방유동에 대한 사례 연구

이광우(Lee Kwang Wu),홍원표(Hong Won pyo),조삼덕(Cho Sam Deok),이대훈(Lee Dae Hun) 대한토목학회 2005 대한토목학회 학술대회 Vol.2005 No.10

인발시험과 이론식을 이용한 강재스트립 보강재에 설치된 지지부재의 지지저항 특성 평가

한중근(Han Jung-Geun),윤원일(Yoon Won-il),홍기권(Hong Ki-Kwon),홍원표(Hong Won-Pyo),이광우(Lee Kwang-Wu),조삼덕(Cho Sam-Deok) 한국토목섬유학회 2010 한국지반신소재학회 논문집 Vol.9 No.2

본 연구에서는 강재스트립 보강재에 지지부재가 결속된 형태의 보강재에 대하여 인발시험을 수행하였으며, 인발시험결과와 기존에 제안된 지지저항 평가식에 의한 결과를 비교함으로서 인발변위 50㎜일 때의 인발력과 최대 인발력에 의한 지지부재의 지지저항 특성을 평기하였다. 인발변위 50㎜일 때의 인발력 적용에 의한 지지저항응력(б<SUB>b</SUB>)은 수직응력 증가에 따라 전면 전단파괴에서 펀칭전단파괴로 근접하였으며, 지지부재 개수의 증가에 따라서는 펀칭전단파괴에서 전면전단파괴로 근접하는 것으로 확인되었다. 최대 인발력을 적용한 지지저항응력(б<SUB>b</SUB>)은 수직응력 조건 및 지지부재 개수와 관계없이 전면전단파괴에 근접하였지만, 보강토옹벽의 허용변위를 고려한다면 설계 적용에는 무리가 있을 것으로 분석되었다. 그리고 Prandtl의 소성이론 및 원주공동확장이론에 의한 이론식을 이용한 지지저항 평가는 인발시험결과가 Prandtl의 소성이론을 이용한 예측결과에 보다 가까운 것으로 확인되었다. 또한 Prandtl의 소성이론 및 원주공동확장이론을 이용한 지지저항 평가모델은 전면전단파괴와 펀칭전단파괴모델 사이에 위치하는 것을 확인하였다. In this study, the pullout tests are conducted to evaluate pullout resistance of steel strip reinforcement with transverse members. The test results are compared with theoretical equations and then the failure mechanism of transverse members is evaluated. The bearing resistance stress(б<SUB>b</SUB>) of transverse members, which is applied pullout force at 50㎜ displacement, is closed from punching shear failure to general shear failure. The behavior by increment of a number of transverse members became closer to general shear failure. The behavior of transverse members at maximum pullout force, which is closed to general shear failure, is indicated that it is unrelated to normal stress and a number of transverse members. However, if the allowable displacement of reinforced soil wall is considered, it is impossible to apply in design. The test results are compared with bearing resistance evaluations using Prandtl's plastic theory and cylindrical cavity expansion theory. The analysis results are indicated that the bearing resistance by pullout tests is closed to predicted result by Prandtl's plastic theory, which are located between general shear failure and punching shear failure.