• 한국환경과학회지
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• 제25권8호
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• pp.1057-1063
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• 2016

The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.

• Asian Journal of Atmospheric Environment
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• 제5권2호
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• pp.105-112
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• 2011

In order to investigate the effects of local and synoptic meteorological conditions on urban scale particulate air pollutants observed over the Busan coastal area, power spectrum analysis was applied to observed particulate matter with an aerodynamic diameter $\leq10\;{\mu}m$ ($PM_{10}$) for the period from 1 October, 1993 to 31 December, 2004. Fast Fourier Transform (FFT) analysis was used to obtain the hourly mean observed $PM_{10}$ concentrations to identify different periodicity scales of $PM_{10}$ concentrations. The results showed that, aside from the typical and well-known periodicities such as diurnal and annual variations caused by anthropogenic influences, three other significant power spectral density peaks were identified: 7-day, 21-day and 2.25-year periodicities. Cospectrum analysis indicated that the seven-day variations were closely related to the synoptic meteorological conditions such as weak wind speed, which are relevant to the stagnant high pressure system slowly passing through the Korean Peninsula. The intra-seasonal 21-day variation was negatively correlated with wind speed but was consistently positively correlated with relative humidity, which is related to aerosol formation that can be achieved as a result of the hygroscopic characteristics of aerosols. However, the quasibiennial 2.25-year variation was correlated with the frequency of Asian dust occurrence, the periodicities of which have been recorded inter-annually over the Korean Peninsula.

• Geomechanics and Engineering
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• 제8권3호
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• pp.391-414
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• 2015

In this paper, stabilities of a plane slide rock slope under different hydraulic distributions were studied based on the nonlinear Barton-Bandis (B-B) failure criterion. The influence of various parameters on the stability of rock slopes was analyzed. Parametric analysis indicated that studying the factor of safety (FS) of planar slide rock slopes using the B-B failure criterion is both simple and effective and that the effects of the basic friction angle of the joint (${\varphi}_b$), the joint roughness coefficient (JRC), and the joint compressive strength (JCS) on the FS of a planar slide rock slope are significant. Qualitatively, the influence of the JCS on the FS of a slope is small, whereas the influences of the ${\varphi}_b$ and the JRC are significant. The FS of the rock slope decreases as the water in a tension crack becomes deeper. This trend is more significant when the flow outlet is blocked, a situation that is particularly prevalent in regions with permafrost or seasonal frozen soil. Finally, the work is extended to study the reliability of the slope against plane failure according to the uncertainty from physical and mechanics parameters.

• Asian Journal of Atmospheric Environment
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• 제10권3호
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• pp.146-155
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• 2016

Spatial and temporal variations of mercury, including dry and wet deposition fluxes, were assessed over Northeast Asia, targeting the Yellow Sea, using meteorology and chemistry models. Four modeling periods, each representative of one of the four seasons, were selected. Modeling results captured general patterns and behaviors, and fell within similar ranges with respect to observations. However, temporal variations of mercury were not closely matched, possibly owing to the effects of localized emissions. Modeling results indicated that dry deposition is correlated with wind speed, while wet deposition is correlated with precipitation amount. Overall, the wet deposition flux of $66ng/m^2-day$ was about twice as large as the dry deposition flux of $32ng/m^2-day$, when averaged over the four modeling periods. Dry deposition occurred predominantly in the form of reactive gaseous mercury (RGM). In contrast, RGM accounted for only about two-thirds of wet deposition, while particulate mercury accounted for the remainder.

• 대한수의학회지
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• 제8권2호
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• pp.65-67
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• 1968

Observations were made to determine the effects of age and season upon the total serum protein values of milk goats(female) and milk cows fed in Korea. The results obtained in this work were summerized as follows; 1. In adults. the average concentrations of total serum protein of milk goats and milk cows were higher than in the younger, and were generally increased with the advance of age. The rate of increase in total serum protein value was more significant in the younger than that of adults. 2. The average concentrations of total serum protein of milk cows were significantly higher than those of milk goats. 3. Seasonal variation of total serum protein value was not observed in milk cows. 4. The average concentration of total serum protein of milk goat fed in Korea was much lower than that reported from the Occident, and this difference seemed to be influenced by the ration low in protein.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1358-1365
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• 2010

Estimating condition of slope is difficult because of nonlinear time dependency and seasonal effects, which affect the displacements. Displacements and displacement patterns of landslides are highly variable in time and space, and a unique approach cannot be defined to model landslide movements. Characteristics of movements are obtained by using a statistical method called Principal Component Analysis(PCA). The PCA is a non-parametric method to separate unknown, statistically uncorrelated source processes from observed mixed processes. In the non-parametric approaches, no physical assumptions of target systems are required. Instead, since the "best" mathematical relationship is estimated for given data sets of the input and output measured from target systems. As a consequence, non-parametric approaches are advantageous in modeling systems whose geomechanical properties are unknown or difficult to be measured. Non-parametric approaches are consequently more flexible in modeling than parametric approaches. This method is expected to be a useful tool for the slope management of and alarm systems.

• 한국환경과학회지
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• 제13권1호
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• pp.27-36
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• 2004

Present study analyzed the temporal and spatial characteristics of PM10 pollution in Metropolitan Daegu area based on air pollution monitoring station data and measurements of PM10 concentrations in background area in order to provide essential data for efficient PM10 pollution management. The significant variation of spatial and temporal PM10 concentrations in Daegu area was observed during the study years. The highest maximum PM10 concentration(332 $\mu\textrm{g}$/㎥), average concentration(88 $\mu\textrm{g}$/㎥) and frequency exceeding PM10 daily standard(150 $\mu\textrm{g}$/㎥) were all observed in Namsandong located near a major roadway. The hourly and weekly variations of PM10 concentrations had different pattern for the measurement sites. The monthly and seasonal concentrations exhibited a notable characteristic： the maximum concentration was obtained in spring season, most likely due to Yellow sand effects. Furthermore, this temporal variation of PM10 pollution varied with study site. Meanwhile, the PM10 values measured at the monitoring site, Manchondong, were comparable with those of a control site. The average PM10 concentration ranged from 23 $\mu\textrm{g}$/㎥ to 115 $\mu\textrm{g}$/㎥ with a mean value of 53 $\mu\textrm{g}$/㎥ in the former site and from 22 $\mu\textrm{g}$/㎥ to 91 $\mu\textrm{g}$/㎥ with a mean value of 45 $\mu\textrm{g}$/㎥ in the latter site.

• 한국지구과학회지
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• 제27권7호
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• pp.787-803
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• 2006

The drought index has been developed, based on a $8.6{\mu}m$ surface emissivity in the $8-12{\mu}m$ MODIS channels over the African Sahel region (10-20 N, 13 W-35 W) and the Seoul Metropolitan Area (SMA: 37.2-37.7 N, 126.6-127.2 E). The emissivity indicates the $SiO_2$ strength and can vary interannually by vegetation, water vapor, and soil moisture, as a potential indicator of drought conditions. In a well-vegetated region close to 10 N of the Sahel, the Normalized Difference Vegetation Index (NDVI) showed high sensitivity, while the emissivity did not. On the other hand, the NDVI experienced negligible variability in a poorly vegetated region near 20 N, while the emissivity reflected sensitively the effects of atmospheric water vapor and soil moisture conditions. Seasonal variations of the emissivity (0.94-0.97) have been examined over the SMA during the 2003-2004 period compared to NDVI (or Enhanced Vegetation Index; EVI). Here, the dryness was more severe in urban area with less vegetation than in suburban area; the two areas corresponded to the north and south of the Han river, respectively. The emissivity exhibiting a significant spatial correlation of ${\sim}0.8$ with the two indices can supplement their information.

• 한국식품영양학회지
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• 제21권3호
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• pp.263-268
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• 2008

Codonopsis lanceolata has long been used as a seasonal food and as a traditional tonic medicine with anti-inflammatory and anti-oxidation properties. The present study investigated the in vitro effect of Codonopsis lanceolata extracts on immune function in mice. After preparing a single cell suspension splenocyte proliferation was determined by the MTT(3-[4,5-dimethylthiazol-2-y]-2,5-diphenyl terazolium bromide) assay. The cytokines IL-1${\beta}$, IL-6, and TNF-$\alpha$ were not secreted by macrophages stimulated with or without LPS as determined by an ELISA cytokine kit assay. After a 48-hr incubation with the mitogens ConA or LPS there was an increase in splenocytes proliferation and in the production of IL-1${\beta}$, IL-6, and TNF-$\alpha$ in the suspensions supplemented with 50, 100, 250, 500 ${\mu}g/m{\ell}$ Codonopsis lanceolata water extract. The results suggest Codonopsis lanceolata water extract may enhance immune function by regulating splenocyte proliferation and stimulating cytokine production.

• Smart Structures and Systems
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• 제4권2호
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• pp.183-194
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• 2008

An important historical monument of Cyprus is an aqueduct that was built in 1747 to provide water to the city of Larnaca and to its port. Because of its importance to the cultural heritage of Cyprus, the aqueduct has been selected as one of the case-study monuments in the project Wide-Range Non-Intrusive devices toward Conservation of Historical Monuments in the Mediterranean Area (WIND-CHIME). Detailed drawings of the aqueduct obtained from the Department of Antiquities of Cyprus have been used for the development of a computational model. The model was fine-tuned through the measurement of the dynamic characteristics of the aqueduct using forced and ambient vibrations. It should be noted that measurement of the dynamic characteristics of the structure were performed twice in a period of three years (June of 2004 and May of 2007). Significant differences were noted and they are attributed to soil structure interaction effects due to seasonal variations of the water-level in a nearby salt-lake. The system identification results for both cases are presented here. This monument was used to test the effectiveness of shape memory alloy (SMA) pre-stressed devices, which were developed during the course of the project, in protecting it without spoiling its monumental value.