IT전력밀도에 따른 기축 데이터센터의 리모델링을 위한 설비시스템 계획방법에 관한 사례연구

조진균(Cho, Jinkyun),박우평(Park, Woopyeng) 대한건축학회 2022 대한건축학회논문집 Vol.38 No.5

Numerous data centers have been built and operated since 2000. Now that 20 years have passed, a growing need for remodeling that involves shifting to a new IT environment, upgrading IT equipment, and replacing outdated facility infrastructure is escalating. In this study, three basic independent non-IT system modules for a total IT load of 150 kW were derived to respond to low-density, medium-density, and high-density rack-server configurations according to the IT power density known as a key element of a data center. Additionally, a data center’s cooling strategies were analyzed according to its IT power density. As of 2021, the average IT power density of global data centers was surveyed at the level of 7.8-8.4 kW/rack that involved more than 400 samples. Data center cooling was divided into a room-based cooling for low-density, row-based cooling for medium-density, and rack-based cooling for a high-density IT load. Compared to the ALT-1 of a low-density model, the required area was reduced by 30% for the medium-density model and 55% for the high-density model. As a result of the remodeling cost analysis, the cost increased to 105% for the ALT-2 and 119% for the ALT-3 based on the ALT-1 being 100%. The criterion for data center remodeling is to comprehensively consider the required space, cooling energy efficiency, and construction cost based on the IT power density.

The Bandwidth from the Density Power Divergence

Pak, Ro Jin The Korean Statistical Society 2014 Communications for statistical applications and me Vol.21 No.5

The most widely used optimal bandwidth is known to minimize the mean integrated squared error(MISE) of a kernel density estimator from a true density. In this article proposes, we propose a bandwidth which asymptotically minimizes the mean integrated density power divergence(MIDPD) between a true density and a corresponding kernel density estimator. An approximated form of the mean integrated density power divergence is derived and a bandwidth is obtained as a product of minimization based on the approximated form. The resulting bandwidth resembles the optimal bandwidth by Parzen (1962), but it reflects the nature of a model density more than the existing optimal bandwidths. We have one more choice of an optimal bandwidth with a firm theoretical background; in addition, an empirical study we show that the bandwidth from the mean integrated density power divergence can produce a density estimator fitting a sample better than the bandwidth from the mean integrated squared error.

RF Power 변화에 의한 CdS 박막 특성에 관한 연구

이달호(Dal-Ho Lee),박정철(Jung-Cheul Park) 한국정보전자통신기술학회 2021 한국정보전자통신기술학회논문지 Vol.14 No.2

본 논문은 ITO 유리를 기판으로 사용하여 CdS 박막을 제작하였다. MDS (Multiplex Deposition Sputter System)을 이용하여 RF power와 증착시간을 변화시키면서 소자를 제작하였다. 제작된 시편은 광학적 특성에 대해 분석을 하였다. 본 논문의 목적은 태양전지의 광흡수층에 적용될 수 있는 제작조건을 찾는 것이다. RF power가 50W이고 증착 시간이 10분 일 때, 두께는 64Å로 측정되었다. 100W일떄, 두께는 406Å로 측정되었고, 150W일 때는 두꼐는 889Å로 측정되었다. 박막은 RF power가 증가할수록 두께가 증가되는 것을 확인하였다. 광투과율 측정한 결과, 550~850nm는 RF power가 50W, 100W, 150W일 때 모두 투과율이 대략 70% 이상으로 관찰되었다. RF power가 증가되면 두께가 증가되고 입자 크기가 커지므로 박막의 밀도가 증가되어 광투과율이 감소되었다. RF power를 100W로 하고 증착시간을 15분 일 때, 밴드갭은 3.998eV로 계산되었다. 증착시간을 20분일 때, 3.987eV이고 150W는 15분에서는 3.965eV이며 20분에서는 3.831eV이다. RF power가 증가하면 밴드갭이 증가하는 것으로 측정되었다. XRD 분석에서 RF power와 증착시간의 변화에 관계없이 2Θ=26.44에서의 회절 피크를 관찰할 수가 있었다. 반치폭은 증착시간이 증가하면 감소되는 것을 알 수가 있었다. 그리고 RF power를 일정하게 하고 증착시간을 증가하면 입자크기는 증가되는 것으로 측정되었다. This paper produces CdS thin film using ITO glass as substrates. The MDS (Multiplex Deposition Sputter System) was used to produce devices by changing RF power and deposition time. The manufactured specimen was analyzed for its optical properties. The purpose of this paper is to find the fabrication conditions that can be applied to the photo-absorbing layer of solar cells. When RF power was 50W and deposition time was 10 minutes, the thickness was measured at 64Å. At 100W, the thickness was measured at 406Å and at 150 W, the thickness was measured at 889Å. Thin films were found to increase in thickness as RF power increased. As a result of the light transmittance measurement, 550–850nm was observed to have a transmittance of approximately 70% or more when the RF power was 50W, 100W, and 150W. Increasing RF power increased thickness and increased particle size, resulting in increased thin film density, resulting in reduced light transmittance. When RF power was 100W and deposition time was 15 minutes, the band gap was calculated at 3.998eV. When deposition time is 20 minutes, it is 3.987eV, 150W is 3.965eV at 15 minutes, and 3.831eV at 20 minutes. It was measured that the band gap decreased as the RF power increased. At XRD analysis, diffraction peaks at 2Θ=26.44 could be observed regardless of changes in RF power and deposition time. The FWHM was shown to decrease with increasing deposition time. And it was measured that the particle size increased as RF power was constant and deposition time was increased.

세계 내 타자의 밀도와 저항의 방식 : 청소년소설 『원통 안의 소녀』와 ｢B의 세상｣을 중심으로

박성애(Park, Seong-Ae) 한국문학회 2021 韓國文學論叢 Vol.88 No.-

권력주체가 전유하는 공간에서 타자의 공간은 점점 좁아지고 타자들의 밀도는 낮아진다. 타자들이 자발적으로 권력주체의 공간이 되어 주체의 권력으로 머물기도 하고, 그렇지 않다고 하더라도 그들의 목소리를 의미 있는 공적 언어로 통합할 수 없기 때문에 권력주체의 공간에 타자성은 드러나기 힘들다. ｢B의 세상｣과 『원통 안의 소녀』는 타자적 청소년들이 권력의 공간에서 어떤 질량을 가지고, 어떠한 밀도로 존재하는지를 잘 드러내고 있다. 작품 속 청소년 인물들은 주체의 공간에서 주체의 지식으로 해석되는 존재로, 그들의 타자성을 드러내지 못한다. 이에 ｢B의 세상｣은 공적 발화를 시도하고, 공적인 말을 획득함으로써, 그리고 타자들의 연대를 추구함으로써 타자들의 밀도를 높여가고자 한다. 그리고 『원통 안의 소녀』는 “사귐”을 통한 윤리적 주체되기를 통해 그들의 타자성이 세계에 나타날 수 있고 타자를 위한 미래를 꿈꿀 수 있다고 말한다. 청소년소설은 성인작가가 청소년독자에게 전달하는 것으로, 청소년 세계의 진실에 닿아있는 문학이어야 한다. 청소년은 우리 사회의 타자로 그들의 목소리는 잘 들리지 않기에 타자의 말을 드러내기 위해서는 매개자로서 이 세계의 공적 목소리를 소유한 성인작가의 시선과 ‘말’이 필요하다. 목소리 없는 타자가 권력주체의 공간에서 어떻게 존재하는지를 포착하는 주체의 시선과 그것을 전달하는 말이 필요한 것이다. 그리고 글쓰기를 통해 통합되지 않는 타자의 말을 작가는 주체로서 대신 말할 수 있어야 한다. 이를 위해 성인작가는 권력의 긍정적인 면에 주목할 필요가 있다. 권력은 타자의 목소리를 통합하여 사회에서 소통되는 공적인 말이 되도록 할 수 있다. 우리 세계 청소년 타자에 대해 성인작가주체는 타자의 목소리를 통합하여 그림자 없이 명확한 공적인 말이 되도록 해주어야 한다. 이는 우리 사회의 타자들을 마주한 성인 작가가 글쓰기를 통해 윤리적 주체가 되는 방법이라고 할 수 있다. In the space dominated by the subject of power, the space of the Others becomes narrower and the density of the others decreases. Because the Others become the space of the subject of power voluntarily, otherness can not reveal in that space. ｢B s World｣ and 『The Girl in the Cylinder』 show the youth s mass, density, and way of being in the space of power. Youth characters can not reveal their otherness in the texts, because they are interpreted as the subject s knowledge. Accordingly, youth s character of ｢B s World｣ trys to increase their density by attempting public utterances, and pursuing solidarity with the Others. 『The Girl in the Cylinder』 says that their otherness can appear in this world and they can dream of a future for the Others through becoming an ethical subject through friendship. The youth novel should be a literature that touches the truth of the youth s world because adult writers deliver texts to the youth reader. Because the youth are the Other in our society and their voices are hard to hear, so in order to reveal the Other s words, we need the eyes and words of the adult writer who possesses the public voice of this world as an intermediary. The gaze of the subject that captures how the Other exists in the space of the subject of power and the words to convey it are necessary. The writer should be able to speak instead of the Other s words that are not integrated through writing. For this, adult writers need to pay attention to the positive aspects of power. Power can unite the voices of the Others to become a public word communicated in our society. Adult writers should integrate the youth s voices and make it a clear in this our world. This can be the way for adult writers to become an ethical subject through writing and facing the Others in our society.

Robust Interval Estimation Using Density Power Divergence

Sangjin Lee,Changkon Hong 한국자료분석학회 2022 Journal of the Korean Data Analysis Society Vol.24 No.1

The maximum likelihood estimator (MLE) is known to be asymptotically efficient but it is not robust with respect to outliers and model misspecification. Basu et al. (1998) suggest a family of divergence measures called density power divergences , which is based on density. Each measure in this family is indexed by a single tuning parameter a. This parameter controls the trade-off between asymptotic efficiency and robustness of the estimators. The L₂-distance and the Kullback-Leibler divergence belong to this family. With a appropriately chosen tuning parameter, one can get a minimum density power divergence estimator (MDPDE). For 0 < a < 1, the estimator is in between MLE and minimum L₂-distance estimator L₂E. Note that MLE is efficient-but-nonrobust while L₂E is robust-butinefficient. Hong, Kim (2001) suggest an automatic selection of a. In this paper we will suggest a confidence interval using MDPDE when the data set is contaminated. Bootstrap resampling will be used to obtain the confidence interval. It is expected that the resulting confidence intervals (called MDPD bootstrap confidence intervals) are robust with respect to the outliers. The performances of the MDPDE bootstrap confidence intervals are investigated via simulation study.

Comparison of Anaerobic Power According to the Performance Level of Male Middle School HANDBALL Players

Kim Tae-hun J-INSTITUTE 2019 Kinesiology Vol.4 No.2

Purpose; The purpose of this study is to measure and compare the anaerobic power according to the perfor-mance level of male middle school handball players in order to analyze the difference between the well perform-ing group and the non-performing group, while providing the basic data for improving the performance by de-veloping the anaerobic power of the non-performing group in the future. The subjects of this study are consisted of 9 excellent handball players and 8 non-excellent players of Middle School D of Region D. The criteria for the excellent and non-excellent players provide for excellent players being those who played as starting members at the time of winning the 45th National Youth Athletic Conference in 2016 and the replacement players being the non-excellent players. As for the method of measuring anaerobic power, the Wingate test, which is the anaerobic power test for short term, and blood lactate concentration analysis were performed. The data processing of this study were analyzed using the SPSS 18.0 statistical program, and the mean and standard deviation were calcu-lated for each item. The independent t-test was performed to examine the difference in anaerobic power between the groups, while all statistical significance levels were set to P<.05, respectively. The research results indicated that the excellent players were higher statistically than the non-excellent players in terms of anaerobic mean power(p <.05) and total work(p<.05) considering 1kg of weight for anaerobic power. However, even while the significant difference was demonstrated between the groups in terms of the mean power per kg of weight and total work per kg of weight, it determined that the resistance to the lactic acid generated from a high intensity workout over short term was enhanced via training by the excellent group, which did not yield a significant dif-ference in the maximum lactic acid between the two groups. In conclusion, as for the anaerobic power variable, which has a significant influence on the handball performance, the anaerobic mean power which may be exer-cised by glycolysis continuously over a long term with strong resistance against lactic acid is considered to be important. It is also determined that the anaerobic energy storage method and training method need to be de-veloped accordingly.

능동 전력 디커플링 회로의 커패시턴스 최적 설계에 관한 연구

백기호,박성민,정교범 전력전자학회 2019 전력전자학회 논문지 Vol.23 No.3

Active power decoupling circuits have emerged to eliminate the inherent second-order ripple power in a single-phase power conversion system. This study proposes a design method to determine the optimal capacitance for active power decoupling circuits to achieve high power density. Minimum capacitance is derived by analyzing ripple power in a passive power decoupling circuit, a buck-type circuit, and a capacitor-split-type circuit. Double-frequency ripple power decoupling capabilities are also analyzed in three decoupling circuits under a 3.3 kW load condition for a battery charger application. To verify the proposed design method, the performance of the three decoupling circuits with the derived minimum capacitance is compared and analyzed through the results of MATLAB–Simulink and hardware-in-the-loop simulations.

A New Receiver-side Post Regulator (RSPR) with Simple Phase Detection Method and High Power Density for WPT Systems

이영달 대한전기학회 2023 전기학회논문지 Vol.72 No.5

The wireless power transfer (WPT) systems have to supply a stable output voltage to the battery. However, due to its physically separated structure and unstable communication control between transmitter-side (Tx) and receiver-side (Rx), there should be a battery control converter in front of the battery, causing a large number of components and low power density. To relieve these drawbacks, a new receiver-side post regulator (RSPR) with a simple control method and high power density is proposed in this paper. The proposed RSPR structure can help the WPT system to supply stable output to the battery. Besides, the proposed one can remove complex phase detection and unstable communication control method between Tx and Rx. Moreover, through the integrated single-switch into the rectifier diodes, high power density can be obtained. The effectiveness of the proposed structure is analyzed and verified experimentally by a prototype under 380VDC input and 250W output.

팽창흑연·탄소나노튜브 복합 음극과 탄소나노튜브 양극으로 이루어진 미생물 연료전지의 전력수율 평가

한선기,이채영 대한상하수도학회 2013 상하수도학회지 Vol.27 No.4

Electrochemical redox capacity of a microbial fuel cell (MFC) electrode is an important factor in the power density. This study was conducted to investigate the redox capacity of surface modified anode and cathode electrodes by measuring their conductivities. An anode electrode was modified with nitric acid and a cathode electrode was modified with heat treatment. The anode electrode modified with 20 % of the nitric acid concentration showed the highest conductivity of 6.2 μS/cm/g and the maximum power density of 306.0 mW/m2 when used in a MFC. The cathode electrode modified at 472 ℃ for 18 min showed the highest conductivity of 5.2 μS/cm/g and the maximum power density of 276.2 mW/m2 when used in a MFC. On the other hand, an MFC using both the electrodes showed the highest maximum power density of 408.2 mW/m2. Meanwhile, a control MFC without modified electrodes generated very small voltage (0.014 mV), so the power density could not be measured

전력구 내 전자기파에 대한 작업 환경 측정

강대곤 ( Dae Kon Kang ),박재학 ( Jai Hak Park ) 한국안전학회(구 한국산업안전학회) 2019 한국안전학회지 Vol.34 No.1

Electromagnetic measurements of the power cable tunnel were conducted from August 10 to 20, 2018, in the OO city underground utility tunnel. During this period, the average temperature was 31.89℃ and the humidity was 67.56% in power cable tunnel. As a result of the electromagnetic measurement, the highest electric field was 25.3 V/m and the magnetic flux density was 42.6 μT. The average electric field was 18.56 V/m and the magnetic flux density was 29.32 μT in the power cable tunnel. As a result of comparison with the electric equipment technical standard, the electric field in the power cable tunnel was 0.5% of the electric equipment standard and 35.2% of the magnetic flux density. It’s similar value that electric field is about robotic vacuum(15.53 V/m), and magnetic flux density is similar value about capsule- type coffee machine (23.07 μT). The number of cable lines and the size of the electromagnetic waves were not proportional to each other through comparison of cable lines in the power cable tunnel. It was confirmed that 154 kV, rather than 22.9 kV, could have a greater influence on occupational