• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.1-13
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• 2020

There are several methods of peak-shaving, which reduces grid power demand, electricity bought from electricity utility, through lowering "demand spike" during On-Peak period. An optimization method using linear programming is proposed, which can be used to perform peak-shaving of grid power demand for grid-connected PV+ system. Proposed peak shaving method is based on the forecast data for electricity load and photovoltaic power generation. Results from proposed method are compared with those from On-Off and Real Time methods which do not need forecast data. The results also compared to those from ideal case, an optimization method which use measured data for forecast data, that is, error-free forecast data. To see the effects of forecast error 36 error scenarios are developed, which consider error types of forecast, nMAE (normalizes Mean Absolute Error) for photovoltaic power forecast and MAPE (Mean Absolute Percentage Error) for load demand forecast. And the effects of forecast error are investigated including critical error scenarios which provide worse results compared to those of other scenarios. It is shown that proposed peak shaving method are much better than On-Off and Real Time methods under almost all the scenario of forecast error. And it is also shown that the results from our method are not so bad compared to the ideal case using error-free forecast.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.329-329
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• 2017

The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.279-284
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• 2011

The objective of this study was to evaluate the effects of storage temperature and time on the quality parameters of eggs from laying hens at peak production. A total of 576 eggs were obtained from Lohmann Light-Brown hens, which were collected 3 times when the hens were 26, 27, and 28 weeks old. The fresh eggs were collected and measured within 2 h of being laid. Samples of 48 eggs each were stored in chambers for 2, 5, or 10 d inside a refrigerator ($5^{\circ}C$), at room temperature ($21^{\circ}C$), and at a high temperature ($29^{\circ}C$). As the storage temperature and time increased, egg weight, percentage of albumen, Haugh unit (HU), and yolk color significantly (p<0.001) decreased. In addition, egg shell weight, shell percentage, and albumen weight significantly (p<0.001) decreased with storage time. Yolk weight, yolk percentage, and albumen pH significantly (p<0.001) increased with increasing storage temperature, and yolk pH significantly (p<0.001) increased with increasing storage time. When the storage temperature was increased to $29^{\circ}C$, egg weight loss dramatically increased from 1.74 to 3.67% at 5 and 10 d of storage time, respectively. With the exception of the $5^{\circ}C$ storage temperature, HU dramatically decreased according to storage time and temperature, decreasing from 91.3 to 72.63 at $21^{\circ}C$ and from 87.62 to 60.92 at $29^{\circ}C$ during 10 d of storage; however, this decline was not found at $5^{\circ}C$. A rapid increase in albumen alkalinity was observed even after just 2 d of storage regardless of the storage temperature. Interactions between storage time and temperature were significant (p<0.001) with respect to egg weight loss, egg shell weight and percentage, albumen weight and percentage, yolk weight and percentage, albumen and yolk pH, HU, and yolk color. The results of the current study indicated that eggs from laying hens at peak production had significant deterioration of internal quality with increasing storage temperature and time. The results suggest that egg weight loss, albumen pH, and HU are parameters that are greatly influenced by the storage temperature and time of eggs from hens at peak laying.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.51-58
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• 2010

Dental composites have improved significantly in physical properties over the past few decades. However, polymerization shrinkage and stress is still the major drawback of composites, limiting its use to selected cases. Much effort has been made to make low shrinking composites to overcome this issue and silorane-based composites have recently been introduced into the market. The aim of this study was to measure the volumetric polymerization shrinkage kinetics of a silorane-based composite and compare it with conventional methacrylate-based composites in order to evaluate its effectiveness in reducing polymerization shrinkage. Five commercial methacrylate-based (Beautifil, Z100, Z250, Z350 and Gradia X) and a silorane-based (P90) composites were investigated. The volumetric change of the composites during light polymerization was detected continuously as buoyancy change in distilled water by means of Archemedes' principle, using a newly made volume shrinkage measurement instrument. The null hypothesis was that there were no differences in polymerization shrinkage, peak polymerization shrinkage rate and peak shrinkage time between the silorane-based composite and methacrylate-based composites. The results were as follows: 1. The shrinkage of silorane-based (P90) composites was the lowest (1.48%), and that of Beautifil composite was the highest (2.80%). There were also significant differences between brands among the methacrylate-based composites. 2. Peak polymerization shrinkage rate was the lowest in P90 (0.13%/s) and the highest in Z100 (0.34%/s). 3. The time to reach peak shrinkage rate of the silorane-based composite (P90) was longer (6.7 s) than those of the methacrylate-based composites (2.4-3.1 s). 4. Peak shrinkage rate showed a strong positive correlation with the product of polymerization shrinkage and the inverse of peak shrinkage time (R = 0.95).

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.994-998
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• 1999

To evaluate the effects of sucrose-fatty acid ester (SE) on bread-making characteristics, the dough mixing, gelatinization, baking properties with the addition of SE alone and together with other surfactants were investigated. SE increased the peak time and the peak height in mixogram, indicating that it contributed the elasticity of dough. In farinogram, SE increased the peak time and mechanical tolerance index, but reduced the dough stability. SE increased the peak viscosity and reduced the gelatinization temperature and maximum consistency temperature in amylogram. SE increased the specific volume of bread loaf and retarded the increase in hardness of bread during storage, showing its anti-staling effects. The maximum anti-staling effect of SE was observed at 0.5% level. The addition of SE (0.2%), SSL (0.15%) and ES-95 (0.15%) blend showed the maximum specific loaf volume, and that of SE (0.25%) and SSL (0.25%) did the maximum anti-staling effect.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.225-233
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• 2000

The aim in this study was to obtain the basic data for estimation of optimal mating time and ovulation time by finding out the relationship between vaginal cytology and reproductive hormone profiles during the estrous cycle in 36 Korea Jin-do bitches. A characteristic features of vaginal cytology during the estorous cycle were the high proportion of superficial cell, anuclear cell and erythrocyte in proestrus, superficial cell, anuclear cell and erythroucyte in estrus, parabasal cell, small and large intermediate cell and leukocytes in diestrus, and parabasal cell and small intermediate cell in anestrus, respectively. Cornification index(CI) was the high proportion in proestrus and estrus, then it was decreaed in diestrus and anestrus. It indicated that the CI was significantly high proportion in proestrus and estrus in comparison with the other phases. Plasma progesterone concentration was below 1.0ng/ml at the first day of vulval bleeding in pregnant and non-pregnat bitches, and then it was increaed slowly. When Day 0 was timed from the day that plasma progesterone concentration was first increased above 4.0ng/ml, plasma progesterone concentrations at Day 0 in pregnant and non-pregnant above 4.0 ng/ml, plasma progesterone concentrations at Day 0 in pregnant and non-pregnant bitches were $5.2{\pm}0.3ng/ml and 5.7{\pm}0.5ng/ml$$46.5{\pm}3.3 ng/ml$ in pregnant bitches and at Day 20 with $39.8{\pm}0.1ng/ml$ in nonpregnant bitches. It indicated that plasma progesterone concentration was higher in pregnant bitches than in non-pregnant bitches. Hereafter plasma progesterone concentration was decreased steadily. At Day 63 which is parturition day, plasma progesterone concentration was decreased below 1.0ng/ml with $0.8{\pm}0.2ng/ml$ in pregnant bitches whereas in the non-pregnant bitches at Day 75 were decreased below 1.0ng/ml with 40.5{\pm}0.4ng/ml$. Plasma progesterone concentrations was maintained below 1.0ng/ml during anestrus in all of them. The plasma estradiol-17 $\beta$ concentration was increased above 1.0 pg/ml at the first day of vulval bleeding and it showed a peak Day-1 with 38.2 pg/ml. Thereafter it was sharply decreased after Day 0, which was the day that plasma progesterone concentration was first increase above 4.0ng/ml, and was maintained below basal levels. In relationship between CI and reproductive hormones, plasma estradiol-17 $\beta$concentration showed a peak at Day-3 and CI showed a peak at Day-1 which was the second day after plasma estradiol-17 $\beta$ peak, and plasma progesterone concentration was first increased above 4.0ng/ml at Day 0 which was the first day after CI peak. CI was first increased above 80% at Day-6 which was the third day before plasma estradio-17 $\beta$ peak and it was maintained above 80% between Days-6 and Day 3 during 10 days, and showed above 90% at Day-3 which was the day that plasma estradiol-17 $\beta$peak and was maintained above 90% between Day-3 and Day 3 during 7 days. In conclusion, ovulation in Koran Jin-do bitches occurred at the first day after CI peak, at the third day after plasma estradiol-17 $\beta$peak and the day when plasma progesterone concentration was first increased above 4.0 ng/ml. And it was estimated that the optimal mating time was the day when the CI was maintained above 90% and plasma progesterone concentration was between 3.0~8.0ng/ml. Therefore plasma progesterone concentration measurement was used for determination of an accurate ovulation time and the optimal mating time but also vaginal cytology, which is low-priced with equipment and is the simple examination method, was reliable method for estimating estrous cycle, optimal breeding time and ovulation time in Korea Jin-do bitches.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.278-282
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• 2010

In this study, the antibacterial activity and component analysis of Persicaria perfoliata extracts were investigated. MIC (Minimum Inhibitory Concentration) values of ethyl acetate fraction from P. perfoliata on Escherichia coli, Propionibacterium acnes, and Staphylococcus aureus were 0.25%, equally. The results showed that the antibacterial activity of the ethyl acetate fraction was the highest in the S. aureus and P. acnes. Ethyl acetate fraction from P. perfoliata extracts showed 5 bands in TLC and 8 peaks in HPLC (320nm). In HPLC chromatogram of ethyl acetate fraction, first main peak 2 (24.99%) and peak 3 (22.65%) were identified as quercetin-3-o-glucuronide and isoquercitrin in the order of elution time. Also, in HPLC chromatogram of deglycosylated fraction, main peak 2 (76.93%) was identified as quercetin in the order of elution time. And these components are very effective as antioxidants. Thus, these results indicate that extract/fractions of P. perfoliata can be applicable to new functional cosmetics for antioxidant, antibacterial activity.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.725-740
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• 2003

Urbanization concerned with concentration of population, activity and expanding the urban changes a natural environmental, and human activity in urban area causes the appearance of a new hydrologic cycle system. This study is carried out the analysis for the characteristics of runoff variation in urban areas with progress of urbanization. To simulate the mechanics of runoffs on small urban watershed, the ILLUDAS model is used in this study. From the analysis of the urban-runoff processes in small urban area with the progress of urbanization, the following conclusions is obtained. It is found in the results of calculated geographical parameter that peak time is quickened by 15∼35 minutes rather than the urbanization before. Also, in the analysis of the peak rate of runoff, the peak flow rise by 60 % than the urbanization before.

• Earthquakes and Structures
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• v.18 no.2
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• pp.163-170
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• 2020

Floor acceleration plays a major role in the seismic design of nonstructural components and equipment supported by structures. Large floor acceleration may cause structural damage to or even collapse of buildings. For precision instruments in high-tech factories, even small floor accelerations can cause considerable damage in this study. Six P-wave parameters, namely the peak measurement of acceleration, peak measurement of velocity, peak measurement of displacement, effective predominant period, integral of squared velocity, and cumulative absolute velocity, were estimated from the first 3 s of a vertical ground acceleration time history. Subsequently, a new predictive algorithm was developed, which utilizes the aforementioned parameters with the floor height and fundamental period of the structure as the new inputs of a support vector regression model. Representative earthquakes, which were recorded by the Structure Strong Earthquake Monitoring System of the Central Weather Bureau in Taiwan from 1992 to 2016, were used to construct the support vector regression model for predicting the peak floor acceleration (PFA) of each floor. The results indicated that the accuracy of the predicted PFA, which was defined as a PFA within a one-level difference from the measured PFA on Taiwan's seismic intensity scale, was 96.96%. The proposed system can be integrated into the existing earthquake early warning system to provide complete protection to life and the economy.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.180-186
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• 1990

A bioequivalence study of ranitidine tablets was conducted according to the Korean Guidine for the Bioequivalence Test using twelve healthy male subjects. The plasma concentration-timecurves of ranitidine from the test and reference tablets showed profound multiple peak phenomenon in each subject as reported earlier. However, the area under the plasma concentration-time curve (AUC) and the maximum ploasma concentration at the first peak ($C_{max1}$) of the two preparations was proven to be equal when analyzed satistically according to the criteria of the guidline;i. e., statistical power (1-$\beta$)was calculated to be over 0.8 under the condition of $\alpha$ = 5% and $\Delta$(minimum detectable difference) = 20%, and the confidence interval of the difference in AUC at 95% confidence level was in the range of $\pm$ 20%, which statisfied the criteria of bioequivalence. Equivalence of the peak concentration of ranitidine at the second peak ($C_{max2}$), and the time to reach the first ($T_{max1}$) and second verify the bioequivalence of $c_{max2}$ , $T_{max1}$ and $T_{max2}$ between the two tablets. However, we conclude that the test and reference tablets are bioequivalent taking the therapeutic characteristics of the ranitidine preparations into consideration.