• Title/Summary/Keyword: AEP

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A Study of Energy Production Change according to Atmospheric Stability and Equivalent Wind Speed in the Offshore Wind Farm using CFD Program (CFD를 이용한 등가풍속 산정과 대기안정도에 따른 연안풍력단지 발전량 변화 연구)

  • Ryu, Geon-Hwa;Kim, Dong-Hyeok;Lee, Hwa-Woon;Park, Soon-Young;Kim, Hyun-Goo
    • Journal of Environmental Science International
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    • v.25 no.2
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    • pp.247-257
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    • 2016
  • To predict annual energy production (AEP) accurately in the wind farm where located in Seongsan, Jeju Island, Equivalent wind speed (EQ) which can consider vertical wind shear well than Hub height wind speed (HB) is calculated. AEP is produced by CFD model WindSim from National wind resource map. EQ shows a tendency to be underestimated about 2.7% (0.21 m/s) than HB. The difference becomes to be large at nighttime when wind shear is large. EQ can be also affected by atmospheric stability so that is classified by wind shear exponent (${\alpha}$). AEP is increased by 11% when atmosphere becomes to be stabilized (${\alpha}$ > 0.2) than it is convective (${\alpha}$ < 0.1). However, it is found that extreme wind shear (${\alpha}$ > 0.3) is hazardous for power generation. This results represent that AEP calculated by EQ can provide improved accuracy to short-term wind power forecast and wind resource assessment.

Comparison of postural control between subgroups of persons with nonspecific chronic low back and healthy controls during the modified Star Excursion Balance Test

  • Shallan, Amjad;Lohman, Everett;Alshammari, Faris;Dudley, Robert;Gharisia, Omar;Al-Marzouki, Rana;Hsu, Helen;Daher, Noha
    • Physical Therapy Rehabilitation Science
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    • v.8 no.3
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    • pp.125-133
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    • 2019
  • Objective: To compare the postural control between non-specific chronic low back pain (NSCLBP) subgroups and healthy people during dynamic balance performance using a modified Star Excursion Balance Test (mSEBT). Design: Cross-sectional study. Methods: Eighteen NSCLBP subjects (9 active extension pattern [AEP], 9 flexion pattern [FP]), and 10 healthy controls were enrolled in this study. All subjects performed mSEBT on their dominant leg on a force plate. Normalized reach distance and balance parameters, including the center of pressure (COP) displacement and velocity, were recorded. Results: There were significant differences in mean reach distances in both posterolateral and posteromedial (PM) reach directions between AEP and healthy subjects (p<0.001) and between FP and healthy subjects (p<0.001). However, there were no significant differences among the three groups in the anterior reach direction. Also, the results showed no significant differences in mean COP variables (velocity and displacement) between pooled NSCLBP and healthy subjects. However, the subjects were reclassified into AEP, FP and healthy groups and the results showed a significant difference in mean COP velocity in the PM direction between AEP and FP subjects (p=0.048), and between AEP and healthy subjects (p=0.024). Conclusions: The findings in this study highlight the heterogeneity of the individuals with NSCLBP and the importance of identifying the homogenous subgroups. Individuals with AEP and FP experience deficits in dynamic postural control compared to healthy controls. In addition, the findings of this study support the concept of the Multidimensional Classification System.

Acute Eosinophilic Pneumonia Following Secondhand Cigarette Smoke Exposure

  • Chung, Min Kyung;Lee, Seok Jeong;Kim, Mi Yeon;Lee, Jin Hwa;Chang, Jung Hyun;Sim, Sung Shin;Ryu, Yon Ju
    • Tuberculosis and Respiratory Diseases
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    • v.76 no.4
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    • pp.188-191
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    • 2014
  • Acute eosinophilic pneumonia (AEP) is a disease characterized by an acute febrile onset, eosinophilia in bronchoalveolar lavage fluid, and a dramatic response to corticosteroids. Although many studies have reported a close relationship between direct cigarette smoking and AEP, few studies have identified an association between passive smoking and AEP. Here, we report a case of AEP in a 19-year-old female with cough, fever, and dyspnea after 4 weeks of intense exposure to secondhand smoke for 6 to 8 hours a day in an enclosed area.

Development of Wind Farm AEP Prediction Program Considering Directional Wake Effect (방향별 후류를 고려한 풍력발전단지 연간 에너지 생산량 예측 프로그램 개발 및 적용)

  • Yang, Kyoungboo;Cho, Kyungho;Huh, Jongchul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.7
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    • pp.469-480
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    • 2017
  • For accurate AEP prediction in a wind farm, it is necessary to effectively calculate the wind speed reduction and the power loss due to the wake effect in each wind direction. In this study, a computer program for AEP prediction considering directional wake effect was developed. The results of the developed program were compared with the actual AEP of the wind farm and the calculation result of existing commercial software to confirm the accuracy of prediction. The applied equations are identical with those of commercial software based on existing theories, but there is a difference in the calculation process of the detection of the wake effect area in each wind direction. As a result, the developed program predicted to be less than 1% of difference to the actual capacity factor and showed more than 2% of better results compared with the existing commercial software.

A Correlational Study between Auditory Evoked Potential and Subdural Hematoma for the Diveloprnent of a Noninvasive ICP Monitoring System (비침습적 뇌내압 측정 시스템의 개발을 위한 청각유발전위와 경막혈종간의 상관관계 분석에 관한 연구)

  • ;C.S. Lessard
    • Journal of Biomedical Engineering Research
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    • v.16 no.2
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    • pp.167-174
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    • 1995
  • Development of a noninvasive intensive care system calls for the use of evoked potentials (EPs) as a means of diagnosing traumatic head-injured patients. The experiment entails surgically placing two subarachnoid bolts and a subdural balloon through the skull to simulate a subdural hematoma. Using various levels of intracranial pressure (ICP) and/or different sizes of balloons, auditory evoked potentials (AEPs) were recorded from a rabbit. Six positive peak latencies ($P_1 - P_6$) and five negative peak latencies ($N_l- N_5$) were extracted from an averaged AEP waveform. Multiple regression analyses were performed for determining. a relationship between the ICP and AEP peak latencies. The results indicate that a major correlation of ch, mges on AEP peak latencies is due to mechanical forces of a mass (inflated balloon simulating a hematoma) in the distortion of the brain matter rather than increased ICP itself.

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Evaluation of Power Performance by Anemometer on WTGS (풍력발전기 너셀에 장착된 풍속계를 이용한 출력성능 평가)

  • Kim, Soo-Sang;Park, Se-Kwang
    • Journal of Sensor Science and Technology
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    • v.21 no.4
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    • pp.303-310
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    • 2012
  • We carried out the power performance evaluation for 1.5 MW${\times}$2 by using anemometer installed on WTGS(Wind Turbine Generator System) in the wind farm at Shi-hwa bang-a-mu-ri. In this paper, we compared and analyzed the performance of guaranteed output and measured output of WTGS which includes output curve, output coefficient, AEP(Annual Energy Product) and availability, etc.. The power performance of WTGS was optimized in the low wind speed sections(3 m/s ~ 10 m/s) and the measured output was more produced by AEP 109 % and availability 112 % than the guaranteed output. In addition, we could also cut the high cost of testing WTGS performance by using anemometer as a substitute for weather mast.

EVALUATION OF AUDITORY EVOKED POTENTIALS IN WHITE NEW ZEALAND RABBITS WITH SIMULATED SUBDURAL HEMATOMA AND INCREASED INTRACRANIAL PRESSURE (경막혈종 및 뇌내압 증가에 따른 청각 유발전위의 분석)

  • Im, Jae-Joong
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.05
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    • pp.171-174
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    • 1992
  • Development of a noninvasive intensive care system calls for the use of evoked potentials (EPs), as a means of diagnosing traumatic head-injured patients. The experiment entails surgically plating two subarachnoid bolts and a subdural balloon through the skull to simulate a subdural hematoma. Using various levels of intracranial pressure (ICP) and/or different sizes of balloons, auditory evoked potentials (AEPs) were recorded from a rabbit. Six positive peat latencies ($P_1-P_6$) and five negative peak latencies ($N_1-N_5$) were extracted from an averaged AEP waveform. Multiple regression analyses were performed for determining a relationship between the ICP and AEP peak latencies. The results indicate that a major correlation of changes on AEP peak latencies is due to mechanical forcer of a mass (inflated balloon simulating a hematoma) in the distortion of the brain matter rather than increased ICP.

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Strength Comparision of a Double-Deck Train Carbody by Optimization of the Underframe Thicknesses (언더프레임 두께 최적화에 따른 2층열차의 구조강도비교)

  • Hwnag Won-Ju;Kim Hyeung-Jin
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.748-753
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    • 2004
  • Aluminum alloy is very useful material for high speed transportations due to its high strength and light weight characteristics. Especially because of a weight reduction a large extrustion of aluminum alloy carbody has been manufactured. This aluminum extruded panel is a hallow extruded panel. This shape and thickness is various by designer's sense and experience and VAW's profiles. So it is important to find an optimized shape and thickness of AEP. In this study we get the AEP's thickness to minimize a weight by applying an applying an optimization algorithm. The results of the study can be used as basic guidelines double-deck trains in the future.

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Optimal Design of Permanent Magnet Wind Generator for Maximum Annual Energy Production (최대 연간 에너지 생산을 위한 영구자석형 풍력발전기의 최적설계)

  • Jung, Ho-Chang;Jung, Sang-Yong;Hahn, Sung-Chin;Lee, Cheol-Gyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.12
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    • pp.2109-2115
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    • 2007
  • The wind generators have been installed with high output power to increase the energy production and efficiency. Hence, Optimal design of the direct-driven PM wind generator, coupled with F.E.M(Finite Element Method) and Genetic Algorithm(GA), has been performed to maximize the Annual Energy Production(AEP) over the whole wind speed characterized by the statistical model of wind speed distribution. Particularly, the parallel computing via internet web service has been applied to loose excessive computing times for optimization. The results of the optimal design of Surface-Mounted Permanent Magnet Synchronous Generator(SPMSG) are compared with each other candidates to verify the usefulness of the maximizing AEP model.

Optimal Design of a Direct-Driven PM Wind Generator Aimed at Maximum AEP using Coupled FEA and Parallel Computing GA

  • Jung, Ho-Chang;Lee, Cheol-Gyun;Hahn, Sung-Chin;Jung, Sang-Yong
    • Journal of Electrical Engineering and Technology
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    • v.3 no.4
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    • pp.552-558
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    • 2008
  • Optimal design of the direct-driven Permanent Magnet(PM) wind generator, combined with F.E.A(Finite Element Analysis) and Genetic Algorithm(GA), has been performed to maximize the Annual Energy Production(AEP) over the entire wind speed characterized by the statistical model of wind speed distribution. Particularly, the proposed parallel computing via internet web service has contributed to reducing excessive computing times for optimization.