• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.2
• /
• pp.153-158
• /
• 2006

A new High Resolution Geometry or HRG imaging instrument is developed by CNES to be carried on-board SPOT 5. The HRG instrument offers a higher ground resolution than that of the HRV/HRVIR on SPOT 1 - 4 satellites. The field width of HRG is 60 km, same as SPOT constellation. With two HRG instruments, a maximum swath of 120 km at 5 m resolution can be achieved. The generation of Digital Elevation Models (DEMs) from satellite stereo images scores over conventional methods of DEM generation using topographic maps and aerial photographs. This global availability of satellite images allows for quicker data processing for an equivalent area. In this study, a HRG stereo images of SPOT 5 over JECHEON has been used with Leica Photogrammetry Suite OrthoBASE Pro tool for the creation of a digital elevation model (DEM). The extracted DEM was compared to the reference DEM obtained from the contours of digital topographic map.

• Journal of Korea Water Resources Association
• /
• v.39 no.10 s.171
• /
• pp.833-844
• /
• 2006

The objective of this study is to evaluate the snowmelt effects on the hydrological components, especially on the runoff, by using the soil water assessment tool(SWAT) which is a continuous semi-distributed long term rainfall-runoff model. The model was applied to the basin located in the upstream of the Chungju Dam. Some parameters in the snowmelt algorithm were estimated for the Chungju basin in order to reflect the snowmelt effects. The snowmelt effects were assessed by comparing the simulated runoff with the observed runoff data at the outlet of the basin. It was found out that the simulated runoff with considering the snowmelt component matches more satisfactorily to the observed one than without considering snowmelt effect. The simulation results revealed that the snowmelt effects were noticeable on March and April. Similar results were obtained at other two upstream gauging points. The effect of the elevation bands which distribute temperature and precipitation with elevation was analyzed. This study also showed that the snowmelt effect significantly affects the temporal distribution as well as quantity of the hydrological components. The simulated runoff was very sensitive to the change of temperature near the threshold temperature which the snowmelt can occur. However, the reason was not accounted for this paper, Therefore, further analyses related to this feature are needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.9
• /
• pp.745-751
• /
• 2014

For the multi-nozzle propulsion, the rupture pressure of nozzle closure has an effect on the initial strain rate of ignition. Moreover, the deviation of rupture pressure for each nozzle closure leads to side forces which can disturb the attitude control of rocket. When designed, it should be considered whether nozzle closures are ruptured equally and exactly in the intented pressure. In this paper, the rupture behavior is analyzed by analytical and experimental methods for plate and "+" notched nozzle closures. The rupture pressure and deviation for operating temperature, whether notched or not and notched directions are analyzed. This paper provides a comparison between rupture pressure prediction of finite elements method which tool is Abaqus/Explicit and results of the rupture test. Jonson-Cook shear failure model which corresponds to the damage initiation criterion were used in this simulation.

• Atmosphere
• /
• v.26 no.2
• /
• pp.277-288
• /
• 2016

Polar lows are intense mesoscale cyclones that mainly occur over the sea in polar regions. Owing to their small spatial scale of a diameter less than 1000 km, simulating polar lows is a challenging task. At King Sejong station in West Antartica, polar lows are often observed. Despite the recent significant climatic changes observed over West Antarctica, adequate validation of regional simulations of extreme weather events such as polar lows are rare for this region. To address this gap, simulation results from a recent version of the Polar Weather Research and Forecasting model (Polar WRF) covering Antartic Peninsula at a high horizontal resolution of 3 km are validated against near-surface meteorological observations. We selected a case of high wind speed event on 7 January 2013 recorded at Automatic Meteorological Observation Station (AMOS) in King Sejong station, Antarctica. It is revealed by in situ observations, numerical weather prediction, and reanalysis fields that the synoptic and mesoscale environment of the strong wind event was due to the passage of a strong mesoscale polar low of center pressure 950 hPa. Verifying model results from 3 km grid resolution simulation against AMOS observation showed that high skill in simulating wind speed and surface pressure with a bias of $-1.1m\;s^{-1}$ and -1.2 hPa, respectively. Our evaluation suggests that the Polar WRF can be used as a useful dynamic downscaling tool for the simulation of Antartic weather systems and the near-surface meteorological instruments installed in King Sejong station can provide invaluable data for polar low studies over West Antartica.

• Journal of the Society of Naval Architects of Korea
• /
• v.32 no.3
• /
• pp.126-134
• /
• 1995

The crack initiation life evaluation which is the most commonly used approach in fatigue strength studies for the designers, is performed for the crankshaft of mid-size engine. In order to evaluate the fatigue strength, structural analysis model and applied loads on crankshaft are prepared based on the cyclic system. Using the response data of the finite element analysis, crack initiation life is predicted and plotted on crankshaft geometric model. In this analysis, general purpose programs such as PATRAN, NASTRAN and EMRC/NISA are actively utilized. Life distribution contour plots, which is not yet established as an active tool in actual design system of ship structure & components, are suggested and examples for active predicting procedure such as stress contour plotting in structure strength analysis, are illustrated. Additionally, several correlated equations for prediction of the crack initiation life are introduced and discussed to improve the fatigue strength prediction of crankshaft.

• Journal of Korean Academy of Nursing
• /
• v.47 no.5
• /
• pp.700-711
• /
• 2017

Purpose: This study aimed to test a proposed structural equation model in which bullying experience, conflict management styles and psychological empowerment predict psychological well-being among Chinese nursing students in clinical placement. Methods: Three hundred and sixty-six nursing students recruited from five hospitals in J city and Y city were assessed with self-report questionnaires on bullying experience, conflict management styles, psychological empowerment and psychological well-being including depression, self-esteem, and academic major satisfaction. Data were analyzed using SPSS version 20.0 and AMOS version 22.0. Results: The evaluation parameters included the comparative fit index at .90, the goodness of fit index at .93, the root mean square error of approximation at .07, and ${\chi}^2/df$ ratio at 2.66, indicating that the proposed structural equation model provided a good fit to the data. Experience of being bullied during clinical placement, conflict management styles and psychological empowerment explained 93.0% of the variance and had significant effects on psychological well-being, with conflict management styles and psychological empowerment mediating the association between bullying and psychological well-being. Conclusion: The findings indicated that mediation by conflict management styles and psychological empowerment alleviated the negative influence of bullying on psychological well-being. To limit bullying and its negative effects, development of effective guidelines to deal with bullying will be a critical tool for both Chinese nursing students and their instructors. Further research should incorporate conflict management styles and psychological empowerment into the specific intervention strategies for handling bullying behaviors among nursing students and staff nurses and promoting nursing students' psychological well-being.

• Biomaterials and Biomechanics in Bioengineering
• /
• v.3 no.1
• /
• pp.15-26
• /
• 2016

Based on a survey done recently in Japan, 30 percent of the serious accidents occurred in oral implant surgery were concerned with the mandibular canal and 3/4 of them were related to drilling. One of the reasons lies in the lack of the education system. To overcome this problem, a new educational system focusing on drilling the mandibular trabecular bone has been developed mainly for dental college students in the form of an oral implant surgery training simulator that enables student to sense the reaction force during drilling. On the other hand, the conventional system uses polymeric model. Based on these systems, two approaches were proposed; the evaluation by experienced clinicians using the simulator, and experimental works on the polymeric model. Focusing on the combination of the drilling force sensed and drilling speed obtained through both approaches, the results were compared. It was found that the polymeric models were much softer especially near the mandibular canal. In addition, the study gave us an insight of the understanding in bone quality through tactile sensation of the drilling force and speed. Furthermore, the clinicians positively reviewed the simulator as a valid tool.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.8 no.2
• /
• pp.97-106
• /
• 2006

Site index is an essential tool to estimate forest productivity. Generally, a site index equation is developed and used from the relationship between stand age and dominant tree heights. However, there is a limit to the use of the site index equation in the application of variable ages, environmental influence, and estimation of site index for the unstocked forest. Therefore, it has been attempted to develop a new site index equation based on various environmental factors including site, climate, and topographical variables. This study was conducted to develop a site index equation based on the relationship between site index and environmental factors for the species of Pinus koraiensis in Yangpyung-Gun, Gyunggi Province. The influence of climatic factors (temperature and solar irradiation ratio), topographical factors (elevation, slope, ratio of slope to valley and aspect) and soil profiles (soil depth by layer and soil consistency) on site index were evaluated by multiple regression analysis. Five environmental factors were selected in the final site index equation for Pinus koraiensis. The site index equation developed in this study was also verified by three evaluation statistics: model's estimation bias, model's precision, and mean square error of measurement. Based on the site index equation, the number of productive areas for Pinus koraiensis were estimated by applying GIS technique to digitized forest maps. In addition, the distribution of productive areas was compared with the areas of current distribution of Pinus koraiensis. It is expected that the results obtained in this study could provide valuable information about the amount and distribution of productive areas for Pinus koraiensis reforestation.

• Journal of Home Health Care Nursing
• /
• v.26 no.1
• /
• pp.5-18
• /
• 2019

Purpose: Frailty is associated with an increased risk of adverse health outcomes. We aimed to review the relationships between frailty and health outcomes in community-dwelling Korean elderly individuals. Methods: Whittemore and Knafls' framework for conducting integrative reviews was used. PubMed, Cumulative Index to Nursing and Allied Health Literature, and six Korean databases were searched. For analysis, the study included articles written in English and Korean published between January 1960 and June 2018. Of the total 1,488 studies found in the databases, we analyzed 15 studies that met the quality of the evaluation criteria. Results: The prevalence of frailty in Korean elderly individuals ranged from 6.5% to 11.7% when divided into three levels of frailty. The health outcomes assessed in relation to frailty were divided into five domains: quality of life, physical health, psychosocial health, health behavior, and health care quality. Frailty was negatively associated with all five domains. Conclusions: Our study suggested that nurses should be aware of the limitations in the physical and cognitive functions of frail elderly individuals and provide tailored interventions for Korean elderly individuals. Furthermore, a large-scale study is needed to develop the Korean model of the frailty assessment tool and to verify the conceptual model of this study.

• Journal of Software Assessment and Valuation
• /
• v.16 no.2
• /
• pp.45-52
• /
• 2020

Traditional methods of detecting security vulnerabilities in source-code require a lot of time and effort. If there is good data, the issue could be solved by using the data with machine learning. Thus, this paper proposes a source-code vulnerability detection method based on machine learning. Our method employs the code2vec model that has been used to propose the names of methods, and uses as a data set, Juliet Test Suite that is a collection of common security vulnerabilities. The evaluation shows that our method has high precision of 97.3% and recall rates of 98.6%. And the result of detecting vulnerabilities in open source project shows hopeful potential. In addition, it is expected that further progress can be made through studies covering with vulnerabilities and languages not addressed here.