• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.185-193
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• 2013

Mineral trioxide aggregate (MTA) has recently been used as a pulpotomy medicament for primary molars. The aim of this study was to evaluate and compare the proliferation and differentiation potential of dental pulp stromal cells of permanent teeth and deciduous teeth cultured on MTA-coated surface. Human dental pulp stromal cells were obtained from human permanent premolars and deciduous teeth and cultured on MTA-coated culture plates. The cells were subjected to proliferation assay and cell cycle analysis. Their differentiation potential was evaluated by analysing changes in the mRNA expressions of runt-related transcriptional factor 2 (Runx2) and alkaline phosphatase (ALP). Morphological changes of cells in direct contact with MTA were observed using scanning electron microscopy (SEM). The proliferation rates, distribution of cell cycles and mRNA expression patterns of Runx2 and ALP were similar in both types of pulpal cells. SEM observations revealed that both types changed into more dendrite-like cells. On the surface of MTA, human dental pulp stromal cells from deciduous and permanent teeth were able to both proliferate and differentiate into cells that induce mineralization. MTA is suitable as a biocompatible pulpotomy medicament for primary teeth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1039-1049
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• 2015

The inflow estimation at large multipurpose dam reservoir is carried out by considering the water balance among the discharge, the storage change during unit time interval obtained from the observed water level near dam structure and area-volume curve. This method can be ideal for level pool reservoir but include potential errors when the inflow is influenced by the water level slope due to backwater effects from upstream flood inflows and strong wind induced by typhoon. In addition, the other uncertainties arisen from the storage reduction due to sedimentation after the dam construction and water level noise due to mechanical vibration transmitted from the electric power generator. These uncertainties impedes the accurate hydraulic inflow measurement requiring exquisite hydrometric data arrangement for reservoir waterbody. In this study, the distributed hydrologic model using UBC-3P boundary setting was applied and its feasibility was evaluated. Finally, the modeling performance has been verified since the calculated determination coefficient has been in between 0.96 to 0.99 after comparing with observed peak inflow and total inflow at Namgang dam reservoir.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.21-30
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• 1991

In Summer, oxygen-deficient water masses were developed extensively in the closed eutrophic bays such as Chinhae Bay which results in mass mortality of marine organisms and severe decrease the production of the bay every year. Under the circumstances, this study was performed to investigate the oxygen depletion relating to eutrophication, and also to evaluate self-purfication capacity of Buk Bay by dissolved oxygen mass balance in 1988. The mean concentration of total inorganic nitrogen, phosphate phosphorus and chlorophyll-a were $11.06{\mu}g-at/l,\;0.80{\mu}g-at/l\;and\;1.11mg/m^3$ respectively, which were over eutrophication criteria. Oxygen-deficient water mass was formed in July with the minimum concentration of 2.08ml/l(mean) at the bottom of all stations and recovered slowly in August. The decay and reaeration coefficient calculated from dissloved oxygen sag curve were 0.222/day and 0.018ml/l/day, respectively. To maintain above 4ml/l of oxygen to prevent oxygen-deficient water mass, it is recommendable to supply as much as 0.856ml/l/day of dissolved oxygen or should be reduced the same mass loading of BOD from watershed by the construction of wastewater treatment plant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.8
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• pp.1168-1175
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• 2012

Gel properties of Mook manufactured from acorn harvested in various countries [domestic (KAS), Chinese (CAS), and North Korea (NAS)] were analyzed according to storage period. Gel properties included water binding, syneresis of gel, DSC (differential scanning calorimetry), X-ray diffraction, SEM (scanning electron microscopy), texture, Hunter's color value, and sensory value. Water binding of NAS, CAS, and KAS were 233.8%, 217.3%, and 215.0%, respectively. Syneresis of gel from KAS, CAS, and NAS were 2.06%, 1.85%, and 1.45%, respectively, after 1 day of storage. There were significant differences upon storage for 1~3 days (p<0.05), whereas were no significant differences upon storage for 4~10 days. Peak temperature of gelatinization property by DSC was $55.28^{\circ}C$ for KAS, $54.45^{\circ}C$ for CAS, and $54.12^{\circ}C$ for NAS after 1 day of storage. Hardness of texture in NAS, KAS, and CAS were 374.9, 357.4, and 348.9, respectively, after 1 day of storage. Hunter's color L value, and a value were highest in NAS, whereas b value was the lowest in CAS. There were no significant differences in any particular sensory values.

• The KIPS Transactions:PartB
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• v.12B no.3 s.99
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• pp.349-356
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• 2005

Artificial Organism-used application areas are expanding at a break-neck speed with a view to getting things done in a dynamic and Informal environment. A use of general programming or traditional hi methods as the representation of Artificial Organism behavior knowledge in these areas can cause problems related to frequent modifications and bad response in an unpredictable situation. Strategies aimed at solving these problems in a machine-learning fashion includes Genetic Programming and Evolving Neural Networks. But the learning method of Artificial-Organism is not good yet, and can't represent life in the environment. With this in mind, this research is designed to come up with a new behavior evolution model. The model represents behavior knowledge with Classification Rules and Enhanced Backpropation Neural Networks and discriminate the denomination. To evaluate the model, the researcher applied it to problems with the competition of Artificial-Organism in the Simulator and compared with other system. The survey shows that the model prevails in terms of the speed and Qualify of learning. The model is characterized by the simultaneous learning of classification rules and neural networks represented on chromosomes with the help of Genetic Algorithm and the consolidation of learning ability caused by the hybrid processing of the classification rules and Enhanced Backpropagation Neural Network.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.782-793
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• 1997

To study the physiological adaptation (shift-up) of phytoplankton under the simulated upwelling conditions, nitrate uptake capacity of Dunaliella tertiolecta batch culture was measured in the laboratory using the stable isotope $^{15}N-KNO_3$. Contrary to the expected, there was no significant relationship between the maximum $V_{NO3}$ (nitrogen specific nitrate uptake rate) and the initial nitrate concentration. However, there was a strong relationship between the maximum $\rho_{NO3}$ (nitrate transport rate) and the initial nitrate concentration of $<25\;{\mu}M$, which was also influenced by the physiological status of the culture. The increase in $V_{NO3}$ was mainly due to the increase in PON (particulate organic nitrogen) concentration and partly due to the increase in $V_{NO3}$. When the phytoplankton population was severely shifted-down, the physiological adaptation of nitrate uptake was significantly inhibited at high initial nitrate concentrations. The timing of the maximum $V_{NO3}$ or $\rho_{NO3}$ was related to the initial nitrate concentration. At higher initial nitrate concentrations, maxima in $V_{NO3}$ and $\rho_{NO3}$ occurred 1 or 2 days later than at lower nitrate concentrations. This relationship was the opposite to the prediction from the shift-up model of Zimmerman et al. (1987), The shift-up process is apparently controlled by an internal time sequence and the initial nitrate concentration, but the magnitude of $V_{NO3}$ was affected little by changes in nitrate concentration.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.727-736
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• 2010

This paper describes results of an preliminary study to produce strain hardening cement-based composites (SHCCs)with consideration of sustainability for infrastructure applications. The aims of this study are to evaluate the influence of recycled materials on the mechanical characteristics of SHCCs, such as compressive, four-point bending, and direct tensile behaviors, and to give basic data for constitutive model for analyzing and designing infra structures with SHCCs. In this study, silica sand, cement, and PVA fibers, were partially replaced with recycled sand, fly-ash, and FET fibers in the mixture of SHCCs, respectively. Test results indicated that fly-ash could improve both bending and direct tensile performance of SHCCs due to increasing chemical bond strength at the interface between PVA fibers and cement matrices. However, SHCCs replaced with PET fibers showed much lower performance in bending and direct tensile tests due to originally low mechanical properties of own fibers, although compressive behavior is similar to PVA2.0 specimen. Also, it was noted that the recycled sand would increase elastic modulus of SHCCs due to larger grain size compared to silica sand. Based on pre-set target value to maintain the performance of SHCCs, it was concluded that the replacement ratio below 20% of fly-ash or below 50% of recycled sands would be desirable for creating sustainable SHCCs.

• Applied Biological Chemistry
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• v.31 no.3
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• pp.241-248
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• 1988

In order to determine the approptiate usage of insecticides to honeybee(Apis mellifera L.), median effective dose to seven insecticides were studied. $LC_(50)$ value of DDT was the highest as being 58 ppm, and that of EPN was the lowest as being 1.61ppm. Various detoxifying enzymes from the midget cf adult worker bee, including microsomal oxidases, glutathione Stransferases, esterases, and DDT-dehydrochlorinase were assayed. Effects of various insecticides on microsomal enzyme activities were as follows: Aldrin epoxidase activity was inhibited by malathione and permethrin treatment. N-demethylase activity was induced by diazinon and EPN treatment and O-demethlase activity was induced by diazinon treatment. Of the glutathione S-transferases, aryltransferase(DCNB conjugation) activity was significantly induced by diazinon, and moderately induced by permethrin. Of the esterases, ${\alpha}-NA$ esterase activity was moderately inhibited by malatjione and permethrin. Acetylcholinesterase activity was not affected by the sublethal exposure of honeybee to the insecticides. Sublethal exposure of honeybee to the insecticides had no effect on DDT-dehydrochlorinase activity, except carbaryl and permethrin were significantly induced.

• Korean Journal of Soil Science and Fertilizer
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• v.13 no.2
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• pp.65-70
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• 1980

This experiment was aimed at selecting the most suitable dispersing agent to the Korean soils. The particle size distribution of 18 soil samples representing the great soil groups in Korea was analysed with 5 different dispersing agents by pipette-method. Passing percent of 0.05, 0.02 and 0.002mm in diameter was used for the comparision of the dispersion capacity of chemical agents. The results obtained are as follows; 1. The influence of chemical agents on dispersion seemed to be greater to finer soil particles. The passing percents of 0.002mm showed a great differences according to the chemical agents used, while little differences was observed in those of 0.05mm. 2. It was showed that sodium pyrophosphate had the highest dispersion capacity for the most of Korean soils, the dispersion capacity of sodium hexametaphosphate was also high enough except for volcanic ash soils. 3. It was recommendable that sodium hexametaphosphate could widely be used as a dispersing agent in the routine analysis of soil particle size distribution except for the Volcanic ash soils. 4. The dispersion of Volcanic ash soils was rather poor when chemical agents used. Therefore, special care should be taken for the dispersion of allophane soils.

• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.423-433
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• 2017

During recent 5 years, it was recorded that 20% of total accident frequency and 30% of total number of death have been occurred due to drowsy driving. Drowsy driving accident is result from the loss of driving ability due to driver's accumulated fatigue. Continuous driving time can be measured as a surrogate variable to quantify the level of fatigue. The main purpose of this research is to investigate statistical correlation between the proportion of continuous driving vehicle (more than 2 hours) and the number of drowsy accidents. To carry this out, continuous driving time was measured using GPS route-guidance trajectory data. Also, accident frequency, traffic volume and segment length were collected to estimate safety performance function (SPF) for Jungbunearuk expressway in Korea. Through various types of estimated SPFs, statistical correlation was analyzed based on estimated statistical indices. This research can provide theoretical background for enforcement to regulate commercial vehicle driver's continuous driving time. In addition, throughout the trajectory data expansion, it is expected that strategy for anti-drowsy driving facilities installation can be established based on the suggested methodology.