• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.17.1-17.7
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• 2016

Objectives This study aimed to evaluate the relationship between residential district of people, such as power plant, steel-mill and petrochemical industries, and health-related quality of life (HRQoL). Methods Using a cross-sectional study design, we randomly recruited participants for our study from industrial areas (thermoelectric power plant, steel-mill, petrochemical industry) and rural areas. Logistic regression analysis was used to identify the relationships between Euro quality of life-5 dimension (EQ-5D) scores and living region, while controlling for sociodemographic characteristics. Results In adjusted model, quality of life decreased with increasing category of age and were lower for females than males. EQ-5D scores of people living in the vicinity of thermoelectric power plant were significant lower than those of people living the vicinity of comparison region (odds ratio, 1.59; 95% confidence interval, 1.00 to 2.53). Conclusions Living region of thermoelectric power plant, was strongly associated with scores on the EQ-5D. More research is needed to elucidate the mechanisms which makes the relationship with the living regions and HRQoL.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.69-71
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• 2008

Recently, the interest on power quality has been hot issue because the equipments cause voltage disturbance and become more sensitive to the voltage disturbance. The DVR(Dynamic Voltage Restorer) is one of the Custom Power Device that can compensate the voltage. DVR operates as a series connected compensator whose output voltage can be controlled system voltage. And the magnitude of compensation voltage is limited by the characteristics of system and load. Compensation capability of DVR was simulated by EMTDC under several condition. This paper analyzed effect of DVR's compensation at power quality test center which has SSFG(Sag, swell, and Flicker Generator, CPDs(SSTS, DVR, DSTATCOM), and loads.

• Tribology and Lubricants
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• 제27권2호
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• pp.65-70
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• 2011

The power servo cylinder for driving accurately turbine stop valve of an atomic power plant is necessary to do turn-over owing to a leakage of oil and a structure problem, especially, it of a power plant be in demand a high quality standard depends entirely on import. There are much problem that the AlBC be to used as a material of piston head in cylinder are caused by wear. Therefore, it is necessary to examine friction characteristics of it. In this study, wear test experiments was carried out with AlBC and SCM440, using reciprocating friction tester of pin on disk. This result was shown that the wear mechanism of AlBC on working condition is adhesive wear and the maximum temperature of infra redray thermal image of frictional surface show over 2 mm from contact surface of pin and disk.

• 한국위성정보통신학회논문지
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• 제12권4호
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• pp.146-151
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• 2017

본 논문은 전력선 통신 시스템에서 에너지 효율을 최적화하기 위해 송신 전력 및 부 채널 할당을 최적화하는 에너지 효율적인 자원 할당 알고리즘을 제안하였다. 제안한 알고리즘은 특히 수신기에 최대의 신호 전력을 전달하기 위해서 기존의 연구와 다르게 주파수에 따라 변하는 전력선 채널의 특성을 시스템 모델에서 고려하였다. 또한, 에너지 효율 함수를 최대화 할 때 송신기의 최대 신호전력 한계 및 최소 데이터 전송률 만족 등 현실적인 제한조건들을 고려하여 전송 알고리즘을 설계하였다. 따라서 본 논문에서는 비선형 분수 프로그래밍과 라그랑지 이중 기법을 이용하여 최적값을 산출하였고 시뮬레이션을 통해 베이스라인 기법 대비 제안한 알고리즘의 에너지 효율 성능의 우수성을 확인하였다.

• 전기학회논문지
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• 제61권11호
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• pp.1571-1577
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• 2012

This paper presents a method for assessing the voltage sag performance of power system involving wind power generation. Wind power generation is considered as one of the most desirable renewable energy sources. However, wind power generation have uncertain energy output and it is difficult to control the output. The existing methods of voltage sag assessment are not reflected the characteristics of wind power generation. Therefore, in order to more accurately assess the voltage sag performance, the probability of wind power operation is evaluated. In this paper, the probability is determined by combining the wind speed model with the output curve of wind turbine. The probability of wind power operation is reflected as a parameter in voltage sag assessment. The proposed method can provide more accurate results of voltage sag assessment for the case involving the wind power generation.

• 전기학회논문지
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• 제61권5호
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• pp.657-663
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• 2012

Recently, by increasing of devices which are sensitive to power quality, the deterioration of power quality has been accelerated. For this reason, the social and economic losses are increased. So not only correct measurement and evaluation, but also countermeasure for improvement of power quality is surely necessary for both electric power supplier and consumer. In this paper, the discrimination algorithm for events and variation occurred in distribution systems using S-transform is proposed. Firstly, we review for events and variations that occur in distribution system. Next, we simulate events and variations on various conditions using ElectroMagnetic Transient Program(EMTP). For the simulation, the IEEE 13 Node Test Feeder and KEPCO's distribution system is modeled. Finally, for the analysis, a modified wavelet transform known as S-transform is adopted to find out the characteristics of each events and variations.

• 콘크리트학회논문집
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• 제11권5호
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• pp.41-49
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• 1999

This study dealt with the applicability and quality control of the concrete using fly ash produced in combined heat power in a construction site. Firstly, chemical and physical characteristics of the fly ash produced in combined heat power plant re analysed. Also, after investigating the properties of flesh and hardened concrete through various experiments, the fly ash concrete was placed in depositing construction in Ulsan Petrochemical Service Co. This field application was focussed on the quality control system in the site as production, placing and curing of concrete. As the result of this study, the quantity of CaO in the fly ash is relatively high based on the chemical analysis. The fly ash concrete showed slumping maintenance and high viscosity properties in the optimal mixing conditions (W/B:44~45%, S/a:$45\pm$2%, W:185kg/m). And, quality control and assurance of the fly ash concrete in actual site were verified by various testing methods.

• 한국멀티미디어학회논문지
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• 제22권8호
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• pp.860-873
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• 2019

LCD backlight boosting and the integration of boosting and dimming are proposed based on image analysis to maximize perceptual image qualities and to reduce display system power. Based on the histogram of the image data, methods for selecting an image suitable for boosting and for adjusting the optimum backlight brightness are proposed. A comprehensive combined optimization method of LCD backlight boosting, dimming and bypass based on image characteristics is also described. Perceptual image quality enhancement and power consumption are evaluated based on well known image databases. Average subjective image quality is improved by 24.8%, RMS contrast is improved more than 20%, and average power consumption is reduced by 15.94% compared to conventional uniform boosting.

• 전기학회논문지
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• 제67권7호
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• pp.854-859
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• 2018

This paper describes the characteristics of a hybrid supercapacitor module for power quality stabilization. Hybrid supercapacitor is an promising energy storage device that positioned between conventional EDLC and Li-ion battery. A cylindrical 7500F hybrid supercapacitor ($60{\times}138mm$) was assembled by using the $Li_4Ti_5O_{12}$ electrode as an anode and activated carbon as a cathode. Considering the ESR and efficiency has been designed to module with 41.6F 480V design results in 180 series combination. In order to determine the characteristics of the hybrid supercapacitor module for power system, hybrid supercapacitor cells were connected in series with active balancing circuit. As a result of measuring the 50kw UPS, it was discharged at the current of 104A~143A during the discharge in the voltage range of 350V~480V, and the compensation time at discharge was measured to be about 30s. These results can be used to stabilization of power quality by applying hybrid supercapacitor module.

• 동력기계공학회지
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• 제14권4호
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• pp.11-16
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• 2010

The evaporation heat transfer characteristics of propane(R-290) in horizontal small diameter tubes were investigated experimentally. The test tubes have inner diameters of 1 mm and 4 mm. Local heat transfer coefficients were measured at heat fluxes of 12, $24\;kW/m^2$, mass fluxes of 150, $300\;kg/m^2s$, and evaporation temperature of $15^{\circ}C$. The experimental results showed that the evaporation heat transfer coefficient of R-290 has an effect on heat flux, mass flux, tube diameter, and vapor quality. The evaporation heat transfer of R-290 has an influenced on nucleate boiling at low quality and convective boiling at high quality. The evaporation heat transfer coefficient of R-290 increases with decreasing inner tube diameter. And the evaporation heat transfer coefficient of R-290 is about 1~3 times higher than that of R-134a.