• Korean Journal of Agricultural Science
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• v.20 no.1
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• pp.68-87
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• 1993

Data acquisition system and computer program developed in this study could be well used in engine vibration analysis. The system and program developed were also operated to be able to control measuring interval, number of channels, number of data. The flywheel was specially studied to provide the proper weight with rubber damper for the engine design at low level of vibration. This study was conducted to obtain basic data which affect the engine vibration. The experiment of this study was performed on original weight flywheel, weight-reduced flywheel, weight-reduced and rubber-coated flywheel, weight-reduced and damper-attached flywheel. Avarage of peak value, maximum vibration, power spectrum density based on FFT analysis are major factors of this experiment. Results were obtained as follows : 1. When rubber was inserted in the flywheel rim of which weight was reduced from 32.2kgf to 24.4kgf, maximum vibration of the engine was decreased 48.3% at X axis, 35.5% at Y axis and 34.6% at Z axis in comparison with the flywheel of original weight. 2. When the flywheel of rubber damper was compared with the original flywheel, the average of absolute vibration for rubber damped flywheel was decreased at X, Y, Z axis and especially its decreasing rate was so high at X-axis comparing with the other flywheel, which implied that rubber damper was very useful to reducing the vibration of the engine at X axis. 3. Hysteresis losses of X, Y, Z axis were greatly decreased in the flywheel with rubber damper on rim. 4. Damped oscillation effect on X and Y axis vibration above average peak vibration by the flywheel of rubber damper on rim was larger than those by the other flywheels. 5. Power spectrums of vibration at real and imaginery part were bi-mode type. The vibration frequency of rubber dampered flywheel which weight is decreased was slightly increased as compared with original flywheel.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1470-1475
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• 1998

Two kinds of Korean rice-wine (Yakju) with different process and ingredients, and Japanese rice-wine (Sake) were chosen for this study, and throughly dried and solubilized in water or cell culture medium. In vitro cytotoxicity assays of the solubilized wine solids exhibited that maximum dilution factors for inhibition of B 16BL6 mouse melanoma cell growth were 16X for herbal medicine-added rice-wine (Korean rice-wine I) and typical Korean rice-wine (Korean rice-wine II), and 8X for Japanese rice-wine. Their cytotoxic effects on HRT18 human colon adenocarcinoma cells were even lower than those on B16BL6 cells. The morphology of the tumor cells were changed by addition of the solubilized wine solids. Inhibitory effect of the rice-wine on in vivo tumor growth and metastasis were monitored after implantation of B16BL6 cells into C57BL/6 mice with daily feeding the solubilized wine solids. Compared to non-fed control groups, B16BL6 tumor growth and metastasis to lung were clearly inhibited by feeding the wine solids, in order of Korean rice-wine I > Korean rice-wine II > Japanese rice-wine. The data of in vitro cytotoxicity and the cell shape changes indicate that the inhibitory effect of tumor progression may be attributed to tumor cell differentiation or immune stimulation induced by certain components in the rice-wine, rather than direct cytotoxicity of the components.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.627-646
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• 2022

Recently, the seriousness of climate change-related problems caused by global warming is growing, and the average temperature is also rising. As a result, it is affecting the environment in which various temperature-sensitive creatures and creatures live, and changes in the ecosystem are also being detected. Seasons are one of the important factors influencing the types, distribution, and growth characteristics of creatures living in the area. Among the most popular and easily recognized plant seasonal phenomena among the indicators of the climate change impact evaluation, the blooming day of flower and the peak day of autumn leaves were modeled. The types of plants used in the modeling were forsythia and cherry trees, which can be seen as representative plants of spring, and maple and ginkgo, which can be seen as representative plants of autumn. Weather data used to perform modeling were temperature, precipitation, and solar radiation observed through the ASOS Observatory of the Korea Meteorological Administration. As satellite data, MODIS NDVI was used for modeling, and it has a correlation coefficient of about -0.2 for the flowering date and 0.3 for the autumn leaves peak date. As the model used, the model was established using multiple regression models, which are linear models, and Random Forest, which are nonlinear models. In addition, the predicted values estimated by each model were expressed as isopleth maps using spatial interpolation techniques to express the trend of plant seasonal changes from 2003 to 2020. It is believed that using NDVI with high spatio-temporal resolution in the future will increase the accuracy of plant phenology modeling.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.143-151
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• 2022

This study was carried out to investigate quantitative characteristics of the cooling effect in a single-span arch greenhouse with roll-up side vents depending on operation of circulation and exhaust fans during ventilation, in order to suggest a practical strategy regarding installation or operation of forced ventilation systems. The examination was conducted under 3 different ventilation conditions (side vents only, side vents + circulation fans, and side vents + circulation fans + exhaust fans). In each condition, variations of internal and external air temperatures and exogenous environmental factors were recorded during ventilation, and the cooling effects were investigated by comparing the normalized temperature difference (NTD) of each ventilation condition. In the morning time (11:00-12:00), a temporary peak in the temperature difference was observed at the beginning of ventilation regardless of ventilation methods. The time taken to the maximum NTD was decreased from 340 s to 110s, and the NTD was dropped from 1.158 to 1.037 as the more forced ventilation systems were operated. The more operations caused the passing time over specific NTD values reduced by 60% as the time was reduced from 1,030 s to 550 s at NTD = 0.8, 1,610 s to 915 s at NTD = 0.6, and 2,315 s to 1,360 s at NTD = 0.4. The temporary peak in NTD was not observed in the afternoon time (14:00-15:00) but it was dropped as quickly as the ventilation started. Also the more operations resulted in the passing time over specific NTD values reduced by 70% as the time was reduced from 560 s to 345 s at NTD = 0.8, from 825 s to 540 s at NTD = 0.6, and from 1,145 s to 810 s at NTD = 0.4. Conclusively, the intervention of the forced ventilation system is recommended in the morning time or in high thermal conditions to achieve more effective and economical ventilation.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.319-344
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• 2015

A seasonal characteristic of marine environment and fish assemblages in the coastal waters of Jeju Island were determined using samples collected by a trammel net in from 2012 to 2013. Annual mean temperature and salinity were $18.8^{\circ}C$, 33.7psu (2012) and $18.8^{\circ}C$, 33.8psu (2013) which shows stable water mass. nutrient concentrations represent that dissolved inorganic nitrogen (DIN) ranged from 0.030 to 0.217mg/L, dissolved inorganic phosphorus (DIP) from 0.002 to 0.010mg/L, and silicate ($SiO_2$) from 0.096 to 0.292mg/L. Chlorophyll a concentrations of phytoplankton ranged from 0.905 to $1.125{\mu}g/L$ were appeared the highest in summer and the lowest in winter. Suspended Solid(SS) concentrations ranged from 1.200 to 2.100mg/L (mean, 1.634mg/L) were appeared the highest in autumn and the lowest in spring. During the survey period, a total of 83 species (48 families and 12 orders) of fishes were identified, Perciformes and Scorpaeniformes accounted for 63.9% of the total number. The number of species was higher in summer than in winter, showing a peak in summer at 57 species and a low in winter at 47 species. The number of individuals and the biomass peaked in summer at 694 individuals and 151.9kg, and were the lowest in autumn at 466 individuals and 106.5kg. The diversity index, evenness index and richness index were appeared 2.92~3.14, 0.75~0.83 and 7.06~8.56 at each stations. the dominance index were appeared highest in spring and summer, were appeared the lowest in winter and autumn. The Filefish (Stephanolepis cirrhifer), Bluestriped angelfish (Chaetodontoplus septentrionalis), Marbled rockfish (Sebastiscus marmoratus), Rabbit fish (Siganus fuscescens), Blackfin sweeper (Pempheris japonica) were dominant species, which occurred abundantly during the entire survey period. The subtropical fishes were identified total of 41 species (49.4%) and the number of species was higher in summer at 29 (50.9%) species and a low in winter at 20 (42.6%) species. The dominant species of subtropical fishes were appeared Bluestriped angelfish, Blackfin sweeper, Rabbit fish, Scarbreast tuskfish (Choerodon azurio), Ballonfish (Diodon holocanthus), Flagfish (Goniistius zonatus), Blue-spotted boxfish (Ostracion immaculatus) in study sites. The subtropical fishes of species, individual and biomass showed significant correlation with environmental factors (Chlorophyll a, DIN, DIP, $SiO_2$) in almost all sampling sites.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.243-251
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• 2012

To investigate the characteristics of rip current occurring at Haeundae beach, observations obtained from a buoy and a CCTV were analyzed and numerical experiments were conducted. During observed rip-current events, the CCTV images showed that a couple of wave-trains, which are close to regular waves with slightly different directions, propagated to the beach, and wavelet analyses of data from the buoy showed very narrow-banded spectra with a peak frequency. From the evidences, it was inferred that a known mechanism of generating rip current due to the nodal line area of honeycomb-patterned wave crest was one of the significant factors of rip current occurrences of Haeundae beach. The mechanism has been explained by the following: When two wave-trains with slightly different directions propagate to a beach, wave crests of the incident wave-trains form honeycomb pattern due to nonlinear interaction. The nodal lines of honeycomb pattern are developed in the cross-shore direction. And longshore currents flow toward the nodal line area which has very low wave energy. Consequently their mass flux is expelled through the area toward the sea direction. To confirm the generation, numerical experiments were performed using a nonlinear Boussinesq equation model. In the cases with two incident wave-trains with slightly different directions and with a monochromatic wave propagating over a submerged shoal, it was seen that the honeycomb pattern of wave crests was well developed, and thus rip currents were evolved along the nodal lines.

• Quality Improvement in Health Care
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• v.1 no.2
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• pp.60-72
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• 1994

Background: The number of outpatients visiting large university teaching hospitals has increased drastically with the introduction of a nationwide health care insurance in 1989 and the improvement of the socio-economic status of the population. This resulted in long waiting times for services, particularly prescribed drugs, which have been patients' chief complaints. Hospitals have tried to solve the problem with limited success because their approach lacked comprehensive research. The objective of this study is to investigate associations between waiting times and variables defining a total work system. Methods: Data for the outpatient pharmacy department in a tertiary care university teaching hospital located in Seoul was analyzed to achieve the study objective. Associations of pharmacy system variables -- work load, work force, pharmacist work schedule, machine problems, and inventory control -- with mean and 99th percentile of waiting times were examined by the hierarchical stepwise regression method. Day was a unit of the analyses. Results: The regression models explained 65.8% of variance in the mean waiting time and 61.34% in the 99th percentile of waiting times. The break-down of the printer for drug envelops, Automatic Tablet Counters (ATCs), and main computer system lasted longer than 30 minutes increased the mean for 7.7 minutes, 4.5 minutes, and 7.0 minutes, respectively, and the 99th percentile for 14.8 minutes, 9.0 minutes, and 15.7 minutes, respectively. Concerning the work force, study results showed that there were significant differences in the productivity of pharmacists with work experience more than three years, one to three years, and less than one year, and showed that peak time aid work by pharmacists at job assignments other than the outpatient pharmacy, part-time pharmacists, and the installation of ATCs were effective in reducing waiting times, Finally, study findings indicated that the operational policy of work assignment and rotation schedule, supply and inventory of drugs at work tables, and readiness for undisrupted work during the work hours could have a significant effect on waiting times. Conclusion: The study results indicated that efforts to reduce waiting times for prescribed drugs should be geared toward every components of the pharmacy work system ranging from work schedule of pharmacists and supply of dugs at work tables. These findings should provide hospital managers with right directions in battling the problem.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.35-43
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• 2013

As texture images have become prevalent throughout a variety of industrial applications, copyright protection of these images has become important issues. For this reason, this paper proposes a color-texture image watermarking algorithm utilizing texture properties inherent in the image. The proposed algorithm selects suitable blocks to embed a watermark using the energy and homogeneity properties of the grey level co-occurrence matrices as inputs for the fuzzy c-means clustering algorithm. To embed the watermark, we first perform a discrete wavelet transform (DWT) on the selected blocks and choose one of DWT subbands. Then, we embed the watermark into discrete cosine transformed blocks with a gain factor. In this study, we also explore the effects of the DWT subbands and gain factors with respect to the imperceptibility and robustness against various watermarking attacks. Experimental results show that the proposed algorithm achieves higher peak signal-to-noise ratio values (47.66 dB to 48.04 dB) and lower M-SVD values (8.84 to 15.6) when we embedded a watermark into the HH band with a gain factor of 42, which means the proposed algorithm is good enough in terms of imperceptibility. In addition, the proposed algorithm guarantees robustness against various image processing attacks, such as noise addition, filtering, cropping, and JPEG compression yielding higher normalized correlation values (0.7193 to 1).

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.109-114
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• 1989

The frequency of appearance of HI antibody against Japanese encephalitis virus was investigated over the three-year period 1982 through 1984. The sample population consisted of 1306 cattle in Saitama prefecture (located in central Japan), and 536 cattle in Kagoshima prefecture (located in southern Japan). During the study period, there was no significant difference in the average antibody-positive rate between cattle in Kagoshima (68.8%) and those in Saitama (65.5%). Variations in the monthly antibody-positive rate and mean monthly antibody titer in the Saitama cattle followed a mountain-like pattern with the peak observed during summer. In the Kagoshima cattle, both parameters also increased in summer and these increases persisted even in winter. The distribution of antibody-positive rate as a function of age ranged from 64.0% to 82.8% in Saitama, though no correlation was observed between these two factors. In the Kagoshima cattle, however, the antibody-positive rate increased with age as follows; the values averaged 29.4% in the one-year-old cattle group, 50.0% in the two-year-old group, 47.4% in the three-year-old group and 74.5% in the four-year-old group. There was no significant correlation between the mean antibody titer and age in either Saitama cattle (15.3~22.5) or Kagoshima cattle (20.0~32.3).

• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.275-290
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• 2012

In this study, we have developed an optimal time distribution model through extraction of peaks over threshold (POT) series. The median values for annual maximum rainfall dataset, which are obtained from the magnetic recording (MMR) and the automatic weather system(AWS) data at Seoul meteorological observatory, were used as the POT criteria. We also suggested the improved methodology for the time distribution of extreme rainfall compared to Huff method, which is widely used for time distributions of design rainfall. The Huff method did not consider changing in the shape of time distribution for each rainfall durations and rainfall criteria as total amount of rainfall for each rainfall events. This study have suggested an extracting methodology for rainfall events in each quartile based on interquartile range (IQR) matrix and selection for the mode quartile storm to determine the ranking cosidering weighting factors on minutely observation data. Finally, the optimal time distribution model in each rainfall duration was derived considering both data size and characteristics of distribution using kernel density function in extracted dimensionless unit rainfall hyetograph.