• Atmosphere
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• v.23 no.4
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• pp.413-424
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• 2013

Urban Heat Island (UHI) intensity is one of vital parameters in studying urban boundary layer meteorology as well as urban planning. Because the UHI intensity is defined as air temperature difference between urban and rural sites, an objective sites selection criterion is necessary for proper quantification of the spatial variations of the UHI intensity. This study quantified the UHI intensity and its spatial pattern, and then analyzed their connections with urban structure and metabolism in Seoul metropolitan area where many kinds of land use and land cover types coexist. In this study, screen-level temperature data in non-precipitation day conditions observed from 29 automatic weather stations (AWS) in Seoul were analyzed to delineate the characteristics of UHI. For quality control of the data, gap test, limit test, and step test based on guideline of World Meteorological Organization were conducted. After classifying all stations by their own local climatological properties, UHI intensity and diurnal temperature range (DTR) are calculated, and then their seasonal patterns are discussed. Maximum UHI intensity was $4.3^{\circ}C$ in autumn and minimum was $3.6^{\circ}C$ in spring. Maximum DTR appeared in autumn as $3.8^{\circ}C$, but minimum was $2.3^{\circ}C$ in summer. UHI intensity and DTR showed large variations with different local climate zones. Despite limited information on accuracy and exposure errors of the automatic weather stations, the observed data from AWS network represented theoretical UHI intensities with difference local climate zone in Seoul.

• Journal of Powder Materials
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• v.23 no.4
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• pp.287-296
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• 2016

$Ni_{1/3}Co_{1/3}Mn_{1/3}(OH)_2$ powders have been synthesized in a continuously stirred tank reactor via a co-precipitation reaction between aqueous metal sulfates and NaOH using $NH_4OH$ as a chelating agent. The co-precipitation temperature is varied in the range of $30-80^{\circ}C$. Calcination of the prepared precursors with $Li_2CO_3$ for 8 h at $1000^{\circ}C$ in air results in Li $Ni_{1/3}Co_{1/3}Mn_{1/3}O_2$ powders. Two kinds of obtained powders have been characterized by X-ray diffraction (XRD), scanning electron microscopy, particle size analyzer, and tap density measurements. The co-precipitation temperature does not differentiate the XRD patterns of precursors as well as their final powders. Precursor powders are spherical and dense, consisting of numerous acicular or flaky primary particles. The precursors obtained at 70 and $80^{\circ}C$ possess bigger primary particles having more irregular shapes than those at lower temperatures. This is related to the lower tap density measured for the former. The final powders show a similar tendency in terms of primary particle shape and tap density. Electrochemical characterization shows that the initial charge/discharge capacities and cycle life of final powders from the precursors obtained at 70 and $80^{\circ}C$ are inferior to those at $50^{\circ}C$. It is concluded that the optimum co-precipitation temperature is around $50^{\circ}C$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.51-58
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• 2020

The purpose of this study is to investigate experimentally the material strength and tensile deformation behavior of highly ductile high-strength cement composites reinforced by synthetic fibers. Materials and mixture proportions were designed to make composites with a strength level of 80 MPa in compression. Two kinds of polyethylene fibers with different properties were employed as reinforcing fibers. A series of experiments on density, compressive strength, and deformation performance was performed. Experimental results showed that the tensile behavior and cracking patterns of cement composite strongly depends on the types of reinforcing fibers. It was also demonstrated that the cement composite with a compressive strength of 77.7 MPa and a tensile strain capacity of 7.9% can be manufactured by using a proper polyethylene fiber.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1841-1848
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• 2013

In this paper, the plans for improvement of real-time security monitoring accuracy and expansion of control region were investigated through comprehensive and systematic collection and analysis of the anomalous activities that inflow and outflow in the network on a large scale in order to overcome the existing security monitoring system based on stylized detection patterns which could correspond to only very limited cyber attacks. This study established an anomaly observation system to collect, store and analyze a diverse infringement threat information flowing into the darknet network, and presented the information classification system of cyber threats, unknown anomalies and high-risk anomalous activities through the statistics based trend analysis of hacking. If this security monitoring system utilizing darknet traffic as presented in the study is applied, it was indicated that detection of all infringement threats was increased by 12.6 percent compared with conventional case and 120 kinds of new type and varietal attacks that could not be detected in the past were detected.

• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1772-1781
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• 2007

Activated sludge was sequentially adapted to benzene, toluene, and o-xylene (BTX) to study the effects on the change of microbial community. Sludge adapted to BTX separately degraded each by various rates in the following order; toluene>o-xylene>benzene. Degradation rates were increased after exposure to repeated spikes of substrates. Eleven different kinds of sludge were prepared by the combination of BTX sequential adaptations. Clustering analyses (Jaccard, Dice, Pearson, and cosine product coefficient and dimensional analysis of MDS and PCA for DGGE patterns) revealed that acclimated sludge had different features from nonacclimated sludge and could be grouped together according to their prior treatment. Benzene- and xylene-adapted sludge communities showed similar profiles. The sludge profile was affected from the point of the final adaptation substrate regardless of the adaptation sequence followed. In the sludge adapted to 50 ppm toluene, Nitrosomonas sp. and bacterium were dominant, but these bands were not dominant in benzene and benzene after toluene adaptations. Instead, Flexibacter sp. was dominant in these cultures. Dechloromonas sp. was dominant in the culture adapted to 50 ppm benzene. Thauera sp. was the main band in the sludge adapted to 50 ppm xylene, but became vaguer as the xylene concentration was increased. Rather, Flexibacter sp. dominated in the sludge adapted to 100 ppm xylene, although not in the culture adapted to 250 ppm xylene. Two bacterial species dominated in the sludge adapted to 250 ppm xylene, and they also existed in the sludge adapted to 250 ppm xylene after toluene and benzene.

• Conservation Science in Museum
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• v.2
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• pp.27-34
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• 2000

24 wooden objects excavated from Daho-ri were identified into 8 categories such as Quercus spp. (37.7%), Castanea crenata (8.3%), Prunus (8.3%), Ilex (4.1%), Alnus spp. (25%), Prunus spp. (4.1%), Zelkova serrata (4.1%) and Fraxinuse (8.3%). Physical properties of the above high water content, high contraction rate and significant density reduction. As for degradation pattern, observation with polarizing microscope showed significant decrease of double reflection phenomenon in most of the excavated objects excluding vessel compared to other kinds of objects, and observation with SEM showed remarkable degradation of organization structure including the 2nd cell wall of wood. Reagent can be easily penetrated and diffused into the objects with high degradation rate, so it's beneficial to treat them with polymers such as PEG#4000(MW:3,350), but in order to prevent contraction and change in shape, high concentration of Reagent is required in treatment to hold wood organization structure.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.822-826
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• 1996

Volatile flavor components from various edible portions of Capsella bursa-pastoris were collected by simultaneous steam distillation-extraction (SDE) method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Thirty four volatile flavor components, including 12 hydrocarbons, 2 aldehydes, 2 ketones, 5 alcohols, 1 ester, 10 acids and 2 miscellaneous ones were confirmed in whole samples. Thirty one components, including 11 hydrocarbons, 5 aldehydes, 4 ketones, 5 alcohols, 1 esters and 5 miscellaneous ones were confirmed in leaves. Twenty four components, including 5 hydrocarbons, 1 aldehyde, 2 ketones, 6 alcohols, 2 esters, 1 acid and 7 miscellaneous ones were confirmed in roots. The kinds and amounts of volatile flavor components revealed different patterns depending upon various edible portions. Relatively greater numbers of volatile flavor components were identified in leaves compared with roots of these wild plants. The characteristic aroma of Capsella bursa-pastoris appeared to be due to combination of C6 alcohol and acids, terpene alcohol and sulfur containing compounds.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.21-26
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• 2008

It was already realized at a current technological level of home network systems that the systems recognizes a user's simple order and carry out the order in the ubiquitous computing environment. However home is not a simple environment consisting into a large number of family members, so various order and situation would be needed accordingly. From now on we need to reach the technological level to infer that how is the user's behavior patterns and what kinds of service is the fittest to user who belong to the ubiquitous computing environment by using the result of the context interpreter. In this regards, active inferred-model needs to be suggested upgrading user's command into one step more higher level than the simple one adapting diversified feature. This study would like to suggest this active model recognizing context, which is user's environmental information applying basic network and inferring Context-based Service that user wants through the recognized result This study proposes a new method that can infer the user's desire in ubiquitous computing environment. First of all, we define a context as user's information of ubiquitous computing environment situation that user belongs to and we classify the context into 4W1H(Where, Who, When, What) formats. We construct Bayesian network and put the factor of context use as Bayesian network nodes. As a result, we can infer the user's behavior pattern and most proper service for user in the intelligent space from the probabilistic result of Bayesian network.

• Korean Journal of Community Nutrition
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• v.1 no.3
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• pp.335-345
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• 1996

The solids(supplementary food) consumption of 200 healthy infants aged from 4 to 6 months have been measured. Five groups were assigned to different feeding patterns. Breastfed group(BF, n=38), formula-fed group(FF, n=102) and mixed-fed group(MF, n=14) were fed breast milk, formula and mixed(breast mile+formula) from birth until 6 months of age respectively. Convert 1 group(C1F, n=14) and convert 2 group(C2F, n=32) were fed breast milk and mixed milk at 2 months of age respectively and were switched to formula thereafter. All infants received solids form 4 months of age. The energy intake from solids at 4 and 6 months averaged 59.1 and 110.3㎉/d among BF groups vs 151.9 and 239.3㎉/d among FF groups respectively. Intakes of protein, calcium and iron were 38-46$\%$, 34-44% and 25-37$\%$ higher in the FF than in the Bf group during the first 6 months. However, no significant differences were found in the intakes of energy and nutrient intakes from solids in all 4 groups excluding BF group(39$\%$). Although BF infant's nutrient intakes from solids were lower than other group's intakes, they intaked evenly solids from various food groups. As the age of infant had increased, the energy intake ratio from solids was cereals and dairy products was increased whereas energy intake ratio from meats, eggs, fruits and vegetables was decreased. TSC4, TSC6(the frequency score for the kinds of weaning food taken) showed no significant difference among 5 feeding groups but CIF-and C2F group's scores tended to be high. Consequently, these results suggest that BF group's solid intake pattern is more desirable and that Korean lactating Mother's dependence on commercial weaning food is too high.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.177-181
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• 2005

Although there are many ways to measure the diameter of a cylindrical object, in this study, the diameter of a cylindrical objects were measured by the geometric optical method and interference-diffraction method which are two kinds of tipical non-contact methods. In geometric optical method, the curved laser beam is formed on the cylindrical surface by spreading the inclined laser beam using the cylindrical lens. The curve is captured by CCD camera and the diameter is calculated by geometry. And the interference and diffraction patterns of investigated cylindrical objects are analyzed in interference-diffraction method. In this study, the cylindrical objects, whose diameters are $0.05\;mm\;\~\;100.50\;mm$ were measured by the geometric optical method and interference-diffraction method. The results show that in each method, the relative errors of the measurement are within $2\%$ and $1\%$, respectively and these non-contact methods can be applied in the quick measurement of many objects.