• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.305-312
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• 2014

This paper discusses real-time peak shaving algorithms for a large-scale battery energy storage system (BESS). Although several transmission and distribution functions could be implemented for diverse purposes in BESS applications, this paper focuses on a real-time peak shaving algorithm for an energy time shift, considering wind power generation. In a high wind penetration environment, the effective load levels obtained by subtracting the wind generation from the load time series at each long-term cycle time unit are needed for efficient peak shaving. However, errors can exist in the forecast load and wind generation levels, and the real-time peak shaving operation might require a method for wind generation that includes comparatively large forecasting errors. To effectively deal with the errors of wind generation forecasting, this paper proposes a real-time peak shaving algorithm for threshold value-based peak shaving that considers fuzzy wind power generation.

• Journal of Korean Society of Transportation
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• v.21 no.6
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• pp.27-42
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• 2003

The basis for planning airport development is the specific demand at peak hour among various aviation demands. The demand at peak hour is regarded to be the source which enables us to estimate the size requirement and capacity of an airport facility. The distribution type of peak hour-operation depends on the difference of aircraft route, geographical location of airport, passengers and cargo. The demand at peak hour is calculated with peak hour factor. So far, the features of peak hour adopted for domestic airport construction plan have been based on the foreign research results. However, it is officially unconfirmed whether the various peak hour characteristics or peak hour factor suggested from foreign studies can be compatible with Korean state or not. In this study, the aircraft operation pattern and the peak hour characteristics are analyzed with hourly data using the operation schedule of an airport for the last 5 years and the actual result statistics of Korean air transportation by airport through the recent 10 Years. After the peak hour factor of the airports is calculated and compared with existing research results, peak hour factor by annual operation frequency is suggested for Korean airports.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.174-186
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• 2019

This study was designed to examine the demographic, economic and organizational characteristics of wage peak workers in public enterprises and their relationship between wage peak system and retirement, which is faster than other areas where the number of elderly workers is growing. The study targets 211 wage peak workers in 19 public enterprises engaged in the wage peak system, considering the level of aging and the size of wage peak workers. According to the demographic and economic characteristics, the results of the study showed that the education level, household income, post retirement cost, retirement saving and investment amount had an effect on wage peak satisfaction, wage peak acceptance, retirement preparation and retirement attitude. Next, aspects of organizational characteristics, there were differences according to position, job title, working period, remaining retirement age, participation in retirement preparation program and wage peak application. Based on these findings, effective wage peak system for the aged society was required to discuss the need for follow-up research by job group, position rank, economic level, and educational level of aged people such as welfare, education and former support.

• Korean Journal of Crystallography
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• v.11 no.3
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• pp.137-146
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• 2000

The stoichiometric mix of evaporating materials for he CuInS₂ single crystal thin films was prepared. To obtain the single crystal thin films, CuINS₂ mixed crystal was deposited on etched semi-insulator GaAs(100) substrate by the hot wall epitaxy(HWE) system. The source and substrate temperature were 640℃ and 430℃, respectively and the thickness of the single crystal thin films was 2 ㎛. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility deduced from Hall data are 9.64x10/sup 22//㎥ and 2.95x10/sup -2/ ㎡/V·s, respectively at 293 K. he optical energy gap was found to be 1.53 eV at room temperature. From the photocurrent spectrum obtained by illuminating perpendicular light on the c-axis of the thin film, we have found that the values of spin orbit coupling splitting ΔSo and the crystal field splitting ΔCr were 0.0211 eV and 0.0045 eV at 10K, respectively. From PL peaks measured at 10K, were can assign the 807.7 nm (1.5350 eV) peak to E/sub x/ peak of the free exciton emission, the 810.3 nm(1.5301 eV) peak to I₂ peak of donar-bound exciton emission and the 815.6 nm(1.5201 eV) peak to I₁ peak of acceptor-bound excition emission. In addition, the peak observed at 862.0 nm(1.4383 eV) was analyzed to be PL peak due to donor-acceptor pair(DAP).

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.193-200
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• 2010

The objective of this study was to investigate the effects of sample preparation, HPLC conditions and peak measurement methods upon determining progesterone content of poly-d,l-lactide-co-glycolide microspheres. A series of the microspheres with different formulations was first prepared. To determine their actual drug contents, the microspheres were dissolved in tetrahydrofuran and diluted with various amounts of methanol to precipitate the polymer. After removal of polymeric precipitates, the filtrates were subject to HPLC analysis under versatile experimental conditions. Interestingly, the composition of a sample solution (e.g., the ratio of methanol to tetrahydrofuran) affected the magnitudes of both peak fronting and peak broadening of progesterone. Its peak became broader and more asymmetrical at lower methanol:tetrahydrofuran ratios. Furthermore, its peak height was influenced by the proportion of tetrahydrofuran in a sample solution. Such problems encountered with tetrahydrofuran were exacerbated when a larger volume of the sample solution was injected onto an analytical column. Under our experimental conditions a peak area measurement provided more accurate and reliable determination of progesterone content in various microspheres than a peak height determination. Optimizing the composition of a sample solution, HPLC chromatographic conditions and peak analysis methods was a prerequisite to an accurate determination of progesterone encapsulated within microspheres.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.37-44
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• 1994

The characteristics of stimulated Brillouin scattering wave for applications to high power laser was experimentally investigated. The peak power reflectivity and the phase conjugation fidelity of Stokes wave with respect to the focal length of lens were measured, and the phase conjugation fidelity for a compressed part of the Stokes wave was also investigated. For the long focal length of lens.(f=100 cm), the peak power of the Stokes wave amounts to about twice as high as that of incident wave. The phase conjugation fidelity for the compressed leading pulse is up to 90%, better than that for other temporal parts of the Stokes pulse. In spatial distribution, the Stokes pulse from the axial region has the largest SBS gain, and it has been ascertained as a best candidate to the application due to excellent pulse compression, peak power reflectivity, and good phase conjugation fidelity.

• Physical Therapy Korea
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• v.13 no.3
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• pp.75-83
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• 2006

The purpose of this study was to examine the isokinetic moment of quadriceps and hamstring strength ratio among women of different ages. The study population consisted of 1,184 women referred to the Health Promotion Center at the S district. All subjects were aged 20 to 69 years old and divided into 5 groups; 20s (n=248), 30s (n=255), 40s (n=248), 50s (n=228), and 60s (n=205). The strength of the knee extensor and flexor, quadriceps, and hamstring of all the participants were assessed at 60 degrees/second with an isokinetic machine. We calculated the peak torque, peak torque %BW (%Body Weight), deficit of peak torque and hamstring/quadriceps ratio of the knee. The data were analyzed by one way ANOVA to investigate statistical differences in strength variation between different age groups and were computed by ${\Delta}%$ difference from women in their 20's. The results were obtained as follows: 1. Peak torque of the knee extensor, quadriceps, were significantly reduced in women older than 30, but peak torque of the knee flexor, hamstring, were significantly reduced in women older than 50 compared to women in their 20's. (p<.05). 2. Peak torque %BW of the knee extensor, quadriceps, were significantly reduced in women older than 20, but peak torque %BW of knee flexor, hamstring, were significantly reduced in women older than 40 compared to women in their 30's (p<.05). 3. Compared to the women in their 20's, there was no significant difference among any of the age groups in the deficit of peak torque of the knee extensor and flexor, but the deficit of peak torque of knee extensor among women between 30 and 50showed significant difference within the normal range of deficit. 4. Compared to the women in their 20's, there was no significant difference among any of the age groups in the hamstring/quadriceps ratio These results showed that peak torque, peak torque %BW, deficit of peak torque, and hamstring/quadriceps ratio of the knee were reduced in each age group, but especially among the women over 50. Further longitudinal study may be needed to see if volume of muscle mass and intervention of exercise affect knee strength in spite of aging.

• International Journal of Highway Engineering
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• v.20 no.3
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• pp.85-92
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• 2018

PURPOSES : In this study, analyze the characteristics of IOC indicator 'threshold' which is needed when evaluating the traffic signal operation status with ESPRESSO in various grade road traffic environment of Seoul metropolitan city and derive suggested value to use in field practice. METHODS : Using the computerized database program (Postgresql), we extracted data with regional characteristics (Arterial, Collector road) and temporal characteristics (peak hour, non-peak hour). Analysis of variance and Duncan's validation were performed using statistical analysis program (SPSS) to confirm whether the extracted data contains statistical significance. RESULTS : The analysis period of the main and secondary arterial roads was confirmed to be suitable from 14 days to 60 days. For the arterial, it is suggested to use 20 km/h as the critical speed for PM peak hour and weekly non peak hour. It is suggested to use 25 km/h as the critical speed for AM peak hour and night non peak hour. As for the collector road, it is suggested to use 20 km/h as the critical speed for PM peak hour and weekly non peak hour. It is suggested to use 30 km/h as the critical speed for AM peak hour and night non peak hour. CONCLUSIONS : It is meaningful from a methodological point of view that it is possible to make a reasonable comparative analysis on the signal intersection pre-post analysis when the signal operation DB is renewed by breaking the existing traffic signal operation evaluation method.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1002-1012
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• 2001

The work reported here is an extensive study of tendon response to multiple cyclic tests including 3% constant peak strain level test (A-type test), 3% constant peak strain level test with two rest periods (B-type test), and 3∼4% different peak strain level test (C-type test). A sufficient number of specimens were tested at each type of the test to statistically evaluate many changes in response during testing and differences in response between each type of the test. In cyclic tests, there were decreses (relaxations) in the peak stresses and hysteresis, increases in the slack strains, and during lower peak strain level (3%) cyclic block after higher peak strain level (4%) cyclic block in the C-type tests. Considering the results of this study and those of the other study of multiple cyclic tests with rest periods by Hubbard and Chun, 1985, recovery phenomena during the rest periods occurred predominantly at the beginning of the rest periods. Consistently in both studies, the effects of rest periods were small and transient compared to the effects of the cyclic extensions. The recovery with cycles at lower peak strain level (3%) after higher peak strain level (4%) in the C-type test has not been previously documented. This recovery seems to be a natural phenomena in tissue behavior so that collagenous structures recover during periods of decreased demand.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.436-441
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• 2007

Background: As patients are positioned at insulated bed and practitioner are positioned at insulated floor or shoes, it could be a cause of lessening effect in acupuncture practice. We investigated how Ground connection could influence on the electrical meridian potential between practitioner and patient during acupuncture practice. Method: We treated 30 normal healthy subjects with acupuncture and measured changes in the electrical potential between the stomach meridian points ST-39 and ST-37 in response to light touch after insertion of a needle at ST-36. At first, we stimulated needle and measured electrical potentials for non ground, patient ground only, practitioner ground only, all ground, respectively. Result: All ground subject elicited positive mean potential $44.6{\pm}19.2{\mu}V$ and showed $181.4{\pm}59.7{\mu}V$ peak to peak potential. practitioner ground only showed negative mean potential $-51.5{\pm}9.3{\mu}V\;and\;367.4{\pm}27.8{\mu}V$ of peak to peak potential. Patient ground only revealed no mean potential as $2.9{\pm}1.3{\mu}V,\;16.4{\pm}11.9{\mu}V$ of peak to peak potential. All ground showed no mean potential as $1.6{\pm}0.7{\mu}V,\;3.3{\pm}1.9{\mu}V$ of peak to peak potential. respectively.