• Journal of the Korean earth science society
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• v.24 no.4
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• pp.303-314
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• 2003

Ocean-air observation using an Automatic Weather Station (AWS) and Conductivity Temperature Depth (CTD) was conducted in the Mid-Yellow Sea off Korea during 8-10 July 2002. A water mass lower than 17$^{\circ}C$ around the Taean peninsula and a tidal front between 36$^{\circ}$20'N and 36$^{\circ}$30'N were observed. The horizontal distribution of air temperature was similar to that of sea surface temperature (SST). Hourly observation around Dukjuk island showed the cold and saline southwesterly and the warm and fresh northeasterly in phase with tidal current. Sea fogs two times formed at 2300 LST 8-0130 LST 9, and 0300-0600 LST 9 July 2002 during the observation period, respectively. During the initial stage of fogs, winds became northeasterly at the speed of 2-4m/s$^{-1}$, and air temperature dropped to 18$^{\circ}C$, as the North Pacific High weakened. The satellite image indicated that sea fogs formed over warm water in the western Yellow Sea and moved eastward toward the observation site, which could be called a steam fog. The fogs dissipated when wind speed and air temperature increased.

• Journal of the Korean earth science society
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• v.38 no.2
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• pp.150-160
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• 2017

In order to determine the porosity of rock, the 'standard test method for porosity and density of rock' proposed by the Korean Society for Rock Mechanics is commonly used. However, the standard test method, which uses a drying oven, takes 8 to 24 hours to complete the test in taking samples out of the oven every four hours and measuring the weight of the specimen. To complement these disadvantages, we devised a method for measuring rock porosity by using a microwave oven. The devised method reduced the cause of errors and the inconvenience occurred in the process of weighing samples by constructing a weight monitoring system, which monitors the drying process. A suitable heating/pause time was set up to maintain the temperature of sample below $105{\pm}3^{\circ}C$ in drying process, and an alarm system was implemented in order to stop drying process when the weight change of the rock sample is within 0.1% of the initial weight. The porosity was determined from the dry weight of the sample, which was obtained by the curve fitting of weight monitoring data. Then, the porosities obtained by using the microwave oven were compared with those obtained by the standard test method. Test results using sandstone samples showed that the porosities obtained by a microwave oven was similar to those obtained by the standard method and the porosity difference between two methods was as large as 0.4%. In addition, repeated porosity measurement using the same specimen showed that the standard deviation of the porosity, which reflects the precision of the measurement was as good as 0.23%. Therefore, a microwave oven porosity measurement system can give the porosity of rock samples with high reliability.

• Journal of the Korean Electrochemical Society
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• v.3 no.3
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• pp.131-135
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• 2000

In order to investigate the origin of capacity fading with charge/discharge cycling in $LiMn_2O_4$ thin film battery, impedance studies have been performed with increasing cycling in $LiMn_2O_4/1M\;LiClO_4-PC/Li$ cells. The fitted values obtained from impedance data show good agreements with the experimental results. Especially, the element of charge transfer resistance of $LiMn_2O_4/liquid$ electrolyte interface initially increased, and then saturated with increasing the charge/discharge cycles, which could explain the cause of initial abrupt capacity fading of $LiMn_2O_4$ thin film with cycling due to interfacial reaction. The steady capacity fading is caused by the increasing of Warburg resistance. The chemical diffusion coefficient of Li ions decreased from $5.15\times10^{-11}cm^2/sec$ at 1st cycles to $6.3\times10^{-12}cm^2/sec$ at 800th cycles, which attributed to the Jahn-Teller distortion/Mn dissolution which diminishes tetra hedral sites necessary for Li diffusion in $LiMn_2O_4$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1084-1096
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• 2016

This paper presents method of design and analysis of a high-speed serial interface connector with a data rate of 12.5 Gbps. A high-speed serial interface connector is composed of various material and complex structures. It is very difficult to match the impedance of each discontinuous portion of connector. Therefore, this paper proposes the structure of a connector line that be simplified a connector. In the structure of proposed connector line, this research presents a method for extracting R, L, C and G parameters, analyzing the differential mode impedance, and minimizing the impedance discontinuity using time domain transmissometry and time domain reflectometry. This paper applies the proposed methods in the connector line to the high-speed serial interface connector. The proposed high-speed serial interface connector, which consists of forty-four pins, is analyzed signal transmission characteristics by changing the width and spacing of the four pins. According to the analysis result, as the width of the ground pin increases, the impedance decreases slightly. And as the distance between the ground pin and the signal pin increases, the impedance increases. In addition, as the width of the signal pin increases, the impedance decreases. And as the distance between the signal pin and the signal pin increases, the impedance decreases. The impedance characteristic of initial connector presents ranges from 96 to $139{\Omega}$. Impedance characteristic after applying the structure of proposed connector is shown as a value between 92.6 to $107.5{\Omega}$. This value satisfies the design objective $100{\Omega}{\pm}10%$.

• Journal of Korean Academy of Nursing
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• v.46 no.6
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• pp.804-812
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• 2016

Purpose: This research was done to identify the hospital arrival rate and factors related to prehospital delay in arriving at an emergency medical center within the golden time after symptom onset in patients with acute myocardial infarction (AMI). Methods: Data used in the research was from the National Emergency Department Information System of the National Emergency Medical Center which reported that in 2014, 9,611 patients went to emergency medical centers for acute myocardial infarction. Prehospital time is the time from onset to arrival at an emergency medical center and is analyzed by subdividing arrival and delay based on golden time of 2 hour. Results: After onset of acute myocardial infarction, arrival rate to emergency medical centers within the golden time was 44.0%(4,233), and factors related to prehospital delay were gender, age, region of residence, symptoms, path to hospital visit, and method of transportation. Conclusion: Results of this study show that in 2014 more than half of AMI patients arrive at emergency medical centers after the golden time for proper treatment of AMI. In order to reduce prehospital delay, new policy that reflects factors influencing prehospital delay should be developed. Especially, public campaigns and education to provide information on AMI initial symptoms and to enhance utilizing EMS to get to the emergency medical center directly should be implemented for patients and/or caregivers.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.239-246
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• 2013

This study observed changes of understory vegetation to evaluate the role of forest aggregate after 15% aggregated retention harvest in mature oak forest (> 100 years) in Gyungsangbukdo Bonghwagun in 2010 and 2011. Spontaneous responses of understory vegetation cover (%), species richness, abundance of plant growth forms (herbaceous and woody plants), and overall attributes (by Ordination analysis) were estimated in aggregate area (0.15 and n=36) and clear cut area (0.85 and n=192) in experimental site and control site (1 and n=300). Based on ordination analysis, overall change of species composition in aggregated sites were relatively lower than in harvest area. Right after treatment, total cover of cutted area slightly decreased from 15.6% to 14.7%, and species richness increased from 14 species to 22 species. Cover and richness in the both of aggregate and control sites increased. In plant growth forms, 15% aggregate harvest revealed positive effects on the abundance (cover and richness) of herbaceous plants than woody group. After retention treatment, overall, edge effect likely played major component of vegetation changes in aggregate forest and in harvested area, mechanical damage from harvest operation and change of forest structure by clear cutting were critical. As pre-treatment data, which are rare in ecological studies in Korea, were critical for interpretation between patterns that may have arisen from spatial distributions in the original forest, our experimental design have higher opportunity for long term monitoring on the effect of forest aggregate and vegetation regeneration in clear cutted area.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.513-521
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• 2019

With rapid climate change and increasing global warming, the distribution of evergreen broad-leaved trees (EBLTs) is gradually expanding to the inland regions of Korea. The aim of the present study was to analyze the survival rate of 148 EBLT plantations measuring 180 ha and to determine the optimal plantation size that would help in coping with climate change in the warm, temperate climate zone of the Korean peninsula. For enhancing the reliability of our estimated survival model, we selected a set of 11 control variables that may have also influenced the survival rates of the EBLTs in the 148 plantations. The results of partial correlation analysis showed that the survival rate of 67.0±26.9 of the EBLTs in the initial plantation year was primarily correlated with plantation type by the crown closure of the upper story of the forest, wind exposure, and precipitation. For predicting the probability of survival by quantification theory, 148 plots were surveyed and analyzed with 11 environmental site factors. Survival rate was in the order of plantation type by the crown closure of upper story of the forest, wind exposure, total cumulative precipitation for two weeks prior to planting, and slope stiffness in the descending order of score range in the estimated survival model for the EBLTs with the fact that survival rate increased with shade rate of upper story to some extent.

• Child Health Nursing Research
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• v.19 no.1
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• pp.29-38
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• 2013

Purpose: This study was done to develop a cell phone addiction scale for Korean parents of young children, and to evaluate the reliability and validity of the developed scale. Methods: The scale was developed through construction of a conceptual framework, generation of initial items, verification of content validity, selection of secondary items, preliminary study, and extraction of final items. Participants were 465 parents and 178 children. Data were analyzed using item analysis, factor analysis, criterion related validity, internal consistency, and split-half reliability. Results: Twenty items were categorized into three factors explaining 60.3% of total variance. Factors were named as withdrawal - 4 items, loss of control - 9 items, and persistence - 7 items. Scores for the scale were significantly correlated with self-control, impulsiveness, cell phone use, and cell phone addiction of children as measured by a scale for Korean children. Cronbach's alpha coefficient for the 20 items was .94, and Guttman coefficient was .87. Scale scores identified children as high risk users, at risk users, or average users by standard scores. Conclusion: The results suggest that the cell phone addiction scale for Korean parents is a reliable and valid instrument to measure cell phone addiction in young children.

• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.97-104
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• 2007

Recently, the demand of the large span structures has been increasing. The large span structures include such a large scaled structures such as: the shell structure, the space frame structure, the membrane structure and the cable structure, etc. The large span structures are supposed to be confirmed and issued carefully at the initial process of the design besides the construction engineering aspects because of the structural specific cause that should solve and accomodate those large and wide space without columns. In the field of the large span structure construction, the erection construction method has been regarded as a major affected aspects on the construction cost, construction term, and stability. In the field of the large span structure construction, there are various construction method and system could be applied depends on the condition of the construction site and other circumstances such a major construction method as: the element method, the block method, the sliding method, the lift-up method and complexed method, etc. In this study, as the case study of the erection construction method of the large span structures, after survey and study that those existing large span structures construction cases which had applied and adopted the election construction method and analysis and classify into the Uoups by the size, span, ceiling height, structural system in odor to supply and suggest the data for the enhancement and development in the field of the erection construction method as a efficient structural solution of the large span structure construction.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.507-516
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• 2013

Mobile devices have limited computing power and resources. Since mobile devices are equipped with rich network connectivity, an approach to subscribe cloud services can effectively remedy the problem, which is called Mobile Cloud Computing (MCC). Most works on MCC depend on a method to offload functional components at runtime. However, these works only consider the limited verion of offloading to a pre-defined, designated node. Moveover, there is the limitation of managing services subscribed by applications. To provide a comprehensive and practical solution for MCC, in this paper, we propose a self-stabilizing process and its management-related methods. The proposed process is based on an autonomic computing paradigm and works with diverse quality remedy actions such as migration or replicating services. And, we devise a pratical offloading mechanism which is still in an initial stage of the study. The proposed offloading mechanism is based on our proposed MCC meta-model. By adopting the self-stabilization process for MCC, many of the technical issues are effectively resolved, and mobile cloud environments can maintain consistent levels of quality in autonomous manner.