• Title/Summary/Keyword: power normalization

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Artificial Neural Network-based Thermal Environment Prediction Model for Energy Saving of Data Center Cooling Systems (데이터센터 냉각 시스템의 에너지 절약을 위한 인공신경망 기반 열환경 예측 모델)

  • Chae-Young Lim;Chae-Eun Yeo;Seong-Yool Ahn;Sang-Hyun Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.883-888
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    • 2023
  • Since data centers are places that provide IT services 24 hours a day, 365 days a year, data center power consumption is expected to increase to approximately 10% by 2030, and the introduction of high-density IT equipment will gradually increase. In order to ensure the stable operation of IT equipment, various types of research are required to conserve energy in cooling and improve energy management. This study proposes the following process for energy saving in data centers. We conducted CFD modeling of the data center, proposed an artificial intelligence-based thermal environment prediction model, compared actual measured data, the predicted model, and the CFD results, and finally evaluated the data center's thermal management performance. It can be seen that the predicted values of RCI, RTI, and PUE are also similar according to the normalization used in the normalization method. Therefore, it is judged that the algorithm proposed in this study can be applied and provided as a thermal environment prediction model applied to data centers.

A Study of Q$_P^{-1}$ and Q$_S^{-1}$ Based on Data of 9 Stations in the Crust of the Southeastern Korea Using Extended Coda Normalization Method (확장 Coda 규격화 방법에 의한 한국남동부 지각의 Q$_P^{-1}$, Q$_S^{-1}$연구)

  • Chung, Tae-Woong;Sato, Haruo;Lee, Kie-Hwa
    • Journal of the Korean earth science society
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    • v.22 no.6
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    • pp.500-511
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    • 2001
  • For the southeastern Korea aound the Yangsan fault we measured Q$_P^{-1}$ and Q$_S^{-1}$ simultaneously by using the extended coda-normalization method for seismograms registered at 9 stations deployed by KIGAM. We analyzed 707 seismograms of local earthquakes that occurred between December 1994 and February 2000. From seismograms, bandpass filtered traces were made by applying Butterworth filter with frequency-bands of 1${\sim}$2, 2${\sim}$4, 4${\sim}$8, 8${\sim}$16 and 16${\sim}$32 Hz. Estimated Q$_P^{-1}$ and Q$_S^{-1}$ values decrease from (7${\pm}$2)${\times}$10$^{-3}$ and (5${\pm}$4)${\times}$10$^{-4}$ at 1.5 Hz to (5${\pm}$4)${\times}$10$^{-3}$ and (5${\pm}$2)${\times}$10$^{-4}$ at 24 Hz, respectively. By fitting a power-law frequency dependent to estimated values over the whole stations, we obtained 0.009 (${\pm}$0.003)f$^{-1.05({\pm}0.14)$ for Q$_P^{-1}$ and 0.004 (${\pm}$0.001)f$^{-0.75({\pm}0.14)$) for Q$_S^{-1}$, where f is frequency in Hz.

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Period Detection of Randomness Ultrasonic Signal Occurred Repeatedly by a Tire Damage (타이어 손상에 의해 반복적으로 발생하는 랜덤성 초음파 신호의 주기검출)

  • Jung, Sun-Yong;Kang, Dae-Soo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.251-258
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    • 2013
  • We studied it about ways to detect damage of a tire about randomness ultrasonic signal which occurs repeatedly while rub a tire of driving car and a road surface. The signal randomness is decreased through the preprocess of short-time energy calculation and the average value of coherence function is used by the normalization expression of the signal randomness. The process limit that can be decide on the dominant period of a signal using the coherence threshold is analyzed and the algorithm to decide the dominant period is proposed by setting up the -3dB threshold of the maximum value on the power spectrum.

A Study on a Novel PMSM Sensorless Control Scheme Based on Back-emf Phase (역기전력 위상을 기초로 한 PMSM의 새로운 센서리스 제어기법에 관한 연구)

  • 이정준;박성준;황상문;정의봉;김철우
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.6
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    • pp.579-586
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    • 2002
  • With increase of servo motor in industrial and home application, a number of papers related to PMSM control have been researched. Among them, sensorless control schemes are especially concerned in a view point of their cost reduction. In a conventional approach, a rotor position is generally estimated by the integration of estimated rotor speed. In this method, because of their tight relationship between the amplitude of back-emf and rotor position, it is somewhat difficult to find two parameters at the same time. To solve this problem, a novel sensorless control scheme is proposed. It utilizes a back-emf normalization, so that it does not require the variables related with the amplitude of back-emf. The validity of the proposed control scheme is verified through experimental results.

A Study on the Algorithm for Detection of Partial Discharge in GIS Using the Wavelet Transform

  • J.S. Kang;S.M. Yeo;Kim, C.H.;R.K. Aggarwal
    • KIEE International Transactions on Power Engineering
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    • v.3A no.4
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    • pp.214-221
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    • 2003
  • In view of the fact that gas insulated switchgear (GIS) is an important piece of equipment in a substation, it is highly desirable to continuously monitor the state of equipment by measuring the partial discharge (PD) activity in a GIS, as PD is a symptom of an insulation weakness/breakdown. However, since the PD signal is relatively weak and the external noise makes detection of the PD signal difficult, it therefore requires careful attention in its detection. In this paper, the algorithm for detection of PD in the GIS using the wavelet transform (WT) is proposed. The WT provides a direct quantitative measure of the spectral content and dynamic spectrum in the time-frequency domain. The most appropriate mother wavelet for this application is the Daubechies 4 (db4) wavelet. 'db4', the most commonly applied mother wavelet in the power quality analysis, is very well suited to detecting high frequency signals of very short duration, such as those associated with the PD phenomenon. The proposed algorithm is based on utilizing the absolute sum value of coefficients, which are a combination of D1 (Detail 1) and D2 (Detail 2) in multiresolution signal decomposition (MSD) based on WT after noise elimination and normalization.

Analysis on the Induction Effects by Separation Distance between the Power Feeding Station and the Telecommunication Cables (고속전철 급전소와의 이격거리에 따른 전력 유도 영향 분석)

  • Choi, Mun-hwan;Lee, Snag-mu;Cho, Pyung-dong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.573-576
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    • 2012
  • We have analyzed the induction effects by separation distance between the power feeding station and the telecommunication cables. To do this we measured the induced voltage in 11 sections(10km) between Jangseong and Imgok at Jeon-nam province using telecommunication cable installed nearby KTX's feeder line. Sub-section has about 1km length of telecommunication cable. And we used normalization method in installed length of telecommunication cables and mutual inductance to analysis the induction effects more rationally.

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Adaptive Feed-forward Control with Reference Model for Position Controller (기준모델과 피드포워드 적응제어를 사용한 위치제어기)

  • 윤명하;최남열;이치환
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.5
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    • pp.413-418
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    • 2002
  • This paper proposed a feed-forward adaptive position controller that is robust for variable Inertia. The control system consists of PI Position controller, feed-forward and model reference adaptive control. A parameter g(t) of the feed-forward adaptive position controller is adapted by using both the reference model speed and position error. So it improves the transient response and reduces the settling time. And normalization function Is used to make linear adaptation time. The validity of the feed-forward adaptive controller is confirmed by simulation results.

Modulation Recognition of BPSK/QPSK Signals based on Features in the Graph Domain

  • Yang, Li;Hu, Guobing;Xu, Xiaoyang;Zhao, Pinjiao
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.11
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    • pp.3761-3779
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    • 2022
  • The performance of existing recognition algorithms for binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals degrade under conditions of low signal-to-noise ratios (SNR). Hence, a novel recognition algorithm based on features in the graph domain is proposed in this study. First, the power spectrum of the squared candidate signal is truncated by a rectangular window. Thereafter, the graph representation of the truncated spectrum is obtained via normalization, quantization, and edge construction. Based on the analysis of the connectivity difference of the graphs under different hypotheses, the sum of degree (SD) of the graphs is utilized as a discriminate feature to classify BPSK and QPSK signals. Moreover, we prove that the SD is a Schur-concave function with respect to the probability vector of the vertices (PVV). Extensive simulations confirm the effectiveness of the proposed algorithm, and its superiority to the listed model-driven-based (MDB) algorithms in terms of recognition performance under low SNRs and computational complexity. As it is confirmed that the proposed method reduces the computational complexity of existing graph-based algorithms, it can be applied in modulation recognition of radar or communication signals in real-time processing, and does not require any prior knowledge about the training sets, channel coefficients, or noise power.

Helicon Discharge Plasma Source and Laser Thomson Scattering System in KRISS

  • Seo, Byeong-Hun;Yu, Sin-Jae;Kim, Jeong-Hyeong;Seong, Dae-Jin;Jang, Hong-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.149-149
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    • 2012
  • We introduce Helicon discharge plasma source and Laser Thomson scattering system recently finished an installation in KRISS. Laser Thomson scattering method is promising for diagnostics in Helicon plasma because a measurement by electrical probe typically used has significant errors due to the gyromotion of electrons induced by high magnetic field. However, we found that LTS is affected by magnetic field so that we applied the normalization method for processing data and the results show a clear Maxwellian distribution at various conditions of magnetic field and RF power at low energy part without distortion.

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Signal Processing Algorithm for a PSD Sensor using Amplitude Modulation/Demodulation (PSD의 신호 처리를 위한 AM 변조 및 복조 회로)

  • La, Jong-Pil;Shin, Myung-Kwan;Park, Kyi-Hwan
    • Proceedings of the KIEE Conference
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    • 2003.11b
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    • pp.71-74
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    • 2003
  • The signal processing algorithm for a PSD(Position Sensitive Detector) using amplitude modulation/demodulation is addressed in this paper. Dark currents and external noises such as daylight and fluorescent lights are eliminated by using amplitude modulation/demodulation and a low pass filter. The proposed amplitude modulation/demodulation method for a PSD sensor is compared with pulse amplitude modulation method. The proposed amplitude modulation is proved to be more accurate and robust than PAM method by analysis and experiments. Multiple measurements using one PSD sensor by amplitude modulation/demodulation is also addressed. The Power variation of light source is compensated by normalization process using a divider.

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