• Journal of the Korean Geotechnical Society
• /
• v.15 no.4
• /
• pp.221-234
• /
• 1999

This paper deals with the application of joint element in the finite element modeling of discontinuities encountered during rock tunneling. A nodal displacement joint element was implemented in a two dimensional finite element program GEOFE2D. The applicability of the joint element for modeling of discontinuities and the numerical stability of the implemented algorithm were examined by comparing the results of reduced small scale model tests as well as commercially available FEM program. The GEOFE2D was then used to analyze a tunnel crossed by a major discontinuity for the purpose of understanding the effect of discontinuity on the tunnel behavior. In addition, a modeling technique for the junction of discontinuity and shotcrete lining was presented. The results of analysis indicated that the stress-strain field around the tunnel is significantly altered by the presence of discontinuity, and that the stresses in the shotcrete lining considerably increase at the junction of the shotcrete lining and the discontinuity. It is therefore concluded that the major discontinuities must be carefully modeled in the finite element analysis of a tunneling problem in order to obtain more reliable results close to actual tunnel behavior.

• The Journal of the Korea Contents Association
• /
• v.8 no.10
• /
• pp.208-216
• /
• 2008

The purpose of this study was to investigate the cause-effect relationship between demographic variables and self-efficacy and job stress of occupational therapists through the analysis of structural equation modeling. The survey was completed 164 occupational therapists using questionnaire consisted of demographic variables, job stress and self-efficacy. The results of this study were follows: Firstly, regarding the measurement about reliability and validity of scale of job stress and self-efficacy, all subfactor of self-efficacy and three subfactor of job stress were useful for occupational therapists; Secondly, there were significant correlations between demographic variables and self-efficacy except the correlations between variables job status; Thirdly, the structural equation modeling were employed to identify the relations among demographic variables, self-efficacy and job stress of occupational therapists. Thus the appropriateness of research model was good. This study focused on exploration of the relationship between self-efficacy and job stress through structural equation modeling.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.5
• /
• pp.445-455
• /
• 2010

In order to effectively predict thermo-acoustic instability within real combustors of rocket engines and gas turbines, in the present study, the Helmholtz equation in conjunction with the time lag hypothesis is discretized by the finite element method on three-dimensional hybrid unstructured mesh. Numerical nonlinearity caused by the combustion response term is linearized by an iterative method, and the large-scale eigenvalue problem is solved by the Arnoldi method available in the ARPACK. As a consequence, the final solution of complex valued eigenfrequency and acoustic pressure field can be interpreted as resonant frequency, growth rate, and modal shape for acoustic modes of interest. The predictive capabilities of the present method have been validated against two academic problems with complex impedance boundary and premixed flame, as well as an ambient acoustic test for liquid rocket combustion chamber with/without baffle.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.28 no.1
• /
• pp.169-178
• /
• 2010

The main purpose of this study is to evaluate the feasibility and the accuracy of ASTER DEM and SRTM DEM covering 99% of the earth surface using large-scale Digital Topographic Map in mountainous area(Sokcho), mixed area(Jinan, mountainous area and even land area) and even land area(Anyang). We made DEM using contour lines of 1:5,000 Digital Topographic Map of study area and also acquired ASTER DEM and SRTM DEM of their corresponding area. In order to verify accuracy of DEM, this study compared ASTER DEM and SRTM DEM data using 15m resolution DEM generated from contour lines of Digital Topographic Map as basis for each study area. To evaluate the accuracy of ASTER and SRTM DEM data, statistical such as RMSE and correlation were calculated and histogram and scatter plot were drawn. The analysis result shows that, both ASTER DEM and SRTM DEM have high accuracy but in aspects of future availability, ASTER DEM covering larger areas bas relatively more potential than SRTM data.

• Journal of the Korean Society for information Management
• /
• v.21 no.1
• /
• pp.187-207
• /
• 2004

Recently there has been a growing interest in the investigation and development of the next generation web - the Semantic Web. From the perspective of a information science, the next generation web - Semantic Web is a metadata initiative. It is reason that one of important stage of Semantic Web Construction is adding formal metadata that describes a Web resource's content and so people can find easy material using metadata. In this paper, 1 designed new application profile metadata architecture as a way to serve as interoperability between various open digital libraries using different information architecture in Semantic Web environment. Based on new application profile metadata architecture, 1 developed union metadata automatic generation and union search algorithm to integrate heterogeneous huge-scale metadata in the open digital library.

• Korean Journal of Adult Nursing
• /
• v.21 no.6
• /
• pp.580-592
• /
• 2009

Purpose: The purpose of this study was to investigate the factors related to Breast cancer Screening using Mammography and CBE of Korean women over 40 years of age. Methods: The participants for this study were 183 Korean women living in 3 urban cities and aged from 40 to 75. The data were collected using structured questionnaires which included sociodemographic factors (11 items), frequency and regularity of mammography and clinical breast examination (7 items), knowledge (16 items), health belief model scale (28 items), and family support (4 items) about breast cancer and breast cancer screening. Frequencies, Chronbach's alpha for reliability, Chi-square, t-test and logistic regression with the SPSS/WIN 12 program were used to analyze the data. Results: The percentages of Korean women who had a mammography and CBE for breast cancer screening were 60.1 and 31.1, respectively. Logistic regression analyses demonstrated that regular check ups and perceived barriers were significant predictors of mammography and CBE use for breast cancer screening. Conclusion: In order to increase the frequency of breast cancer screening practices, educational support and a health care delivery system is needed to improve the chance of regular health check ups.

• Journal of Ocean Engineering and Technology
• /
• v.27 no.3
• /
• pp.73-78
• /
• 2013

CFD (computational fluid dynamics) analyses that considered the dynamic interaction effects between the flow and a turbine were performed to evaluate the power output characteristics of two representative vertical-axis tidal-current turbines: an H-type Darrieus turbine and Gorlov helical turbine (GHT). For this purpose, a commercial CFD code, Star-CCM+, was utilized, and the power output characteristic were investigated in relation to the scale ratio using the relation between the Reynolds number and the lift-to-drag ratio. It was found that the power coefficients were significantly reduced when the scaled model turbine was used, especially when the Reynolds number was lower than $10^5$. The power output characteristics of GHT in relation to the twisting angle were also investigated using a three-dimensional CFD analysis, and it was found that the power coefficient was maximized for the case of a Darrieus turbine, i.e., a twisting angle of $0^{\circ}$, and the torque pulsation ratio was minimized when the blade covered $360^{\circ}$ for the case of a turbine with a twisting angle of $120^{\circ}$.

• Fire Science and Engineering
• /
• v.27 no.2
• /
• pp.31-39
• /
• 2013

The Fire Dynamics Simulator (FDS) has been applied to simulate a full-scale pool fire in well-confined and mechanically ventilated multi-compartments representative of nuclear power plant. The predictive performance of FDS was evaluated through a comparison of the numerical data with experimental data obtained by the OECD/NEA PRISME project. To identify clearly the FDS results regarding to the user-dependence in the process of FDS implementation except for the intrinsic limitation of FDS such as simple combustion model, only the over-ventilated fire condition was chosen. In particular, the importance of accurate boundary conditions (B.C.) in mechanically ventilated system were discussed in details. It was known from FDS results that the B.C. on inlet and outlet vents did significantly affect the thermal and chemical characteristics inside the compartments. Finally, it was confirmed that the FDS imposed an accurate ventilation B.C. provided qualitatively good agreement with temperatures, heat fluxes and concentrations measured inside the nuclear-type multi-compartments.

• Journal of the Korean Geosynthetics Society
• /
• v.6 no.4
• /
• pp.15-20
• /
• 2007

Recently, the demand for industrial and residental land are increasing with economic growth, but it is difficult to acquire areas for development with good ground condition. For efficient and balanced development of land, new development projects are being carried out not only the areas with inland but those with the soft ground as well. As soft grounds have complex engineering properties and high variations such as ground subsidence especially when their strength is low and depth is deep, we need to accurately analyze the engineering properties of soft grounds and find general measures for stable and economic design and management. Vertical drain technology is widely used to accelerate the consolidation of soft clay deposits and dredged soil under pre-loading and various types of vertical drain are used with there discharge capacity. Under field conditions, discharge capacity is changed with various reason, such as soil condition, confinement pressure, long-term clogging and folding of vertical drains and so on. Therefore, many researcher and engineer recommend the use of required discharge capacity. In this paper, the experiment study were carried out to obtain the discharge capacity of six different types of vertical drains by utilizing the large-scale model tests and discharge capacity, degree of consolidation with the time elapsed.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.9
• /
• pp.3885-3890
• /
• 2014

Background: This study aimed to determine nursing student knowledge, behavior and beliefs for breast cancer and breast self-examination receiving courses with a traditional lecturing method (TLM) and the Six Thinking Hats method (STHM). Materials and Methods: The population of the study included a total of 69 second year nursing students, 34 of whom received courses with traditional lecturing and 35 of whom received training with the STHM, an active learning approach. The data of the study were collected pre-training and 15 days and 3 months post-training. The data collection tools were a questionnaire form questioning socio-demographic features, and breast cancer and breast self-examination (BSE) knowledge and the Champion's Health Belief Model Scale. The tests used in data analysis were chi-square, independent samples t-test and paired t-test. Results: The mean knowledge score following traditional lecturing method increased from $9.32{\pm}1.82$ to $14.41{\pm}1.94$ (P<0.001) and it increased from $9.20{\pm}2.33$ to $14.73{\pm}2.91$ after training with the Six Thinking Hats Method (P<0.001). It was determined that there was a significant increase in pre and post-training perceptions of perceived confidence in both groups. There was a statistically significant difference between pre-training, and 15 days and 3 months post-training frequency of BSE in the students trained according to STHM (p<0.05). On the other hand, there was a statistically significant difference between pre-training and 3 months post-training frequency of BSE in the students trained according to TLM. Conclusions: In both training groups, the knowledge of breast cancer and BSE, and the perception of confidence increased similarly. In order to raise nursing student awareness in breast cancer, either of the traditional lecturing method or the Six Thinking Hats Method can be chosen according to the suitability of the teaching material and resources.