• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.11
• /
• pp.957-964
• /
• 2016

This paper presents numerical investigation on behaviors of the rear cover in the vertical launcher under rocket plume loading by using fluid-structure interaction analysis. The rocket plume loading is modeled by the fully Eulerian method and elasto-plastic behavior of the rear cover is predicted by the total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. The present results will be compared with the experimental data in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.9
• /
• pp.5783-5789
• /
• 2014

Since 2002, many domestic companies have been certified for ISMS. On the other hand, certification, such as the need for ost-effectiveness evaluation, is not specifically enforced. Therefore, for more than 10 years, the ISMS implementation and certification system has been used for performance and cost effective business management. In this study, a model for analyzing the effect of certification organizations, ISMS development, and an analysis of the effect of a standardized system for the study was prepared. To this end, the existing maintenance organizations ISMS certification survey was conducted through an analysis of the economic effects. ISMS certification continues to expand or maintain the policy for improvement. The survey data collected by the analysis mechanism for the economic effects of CVM was analyzed.

• The Journal of the Korea Contents Association
• /
• v.16 no.5
• /
• pp.575-582
• /
• 2016

The purpose of this study was to analyse undergraduate medical students' perception of the complementary and alternative medicine(CAM) and Korean medicine. A total of 409 undergraduate medical students participated in the survey. Methodologically, descriptive statistics, MANOVA and logistic regression analysis were conducted. First grade students had more positive perception of CAM and Korean medicine than others. There were no significant differences in the perception of CAM in terms of students' grade and gender(affective attitude, compatability, effectiveness, intention to adoption). However, there was gender difference in perception of Korean medicine. Also, the result showed that students' perception of effectiveness had influence whether they recognize CAM and Korean medicine as medicine or not. Based on results, this study suggest that medical school should develop the curriculum that improve students decision-making ability and critical capacity, especially for lower grades, so that stdents can give reasonable advice for patients' needs.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.7
• /
• pp.237-244
• /
• 2016

The workability of mortar determines its construction performance in a structure showing its designed resistance to external loads. Measuring the rheological properties of mortar is one way of quantifying its workability, but its field-applications are limited due to economical and spatial issues. The robustness of the slump flow test allows its use for evaluating the workability of mortar, even though it is a rather qualitative test method. This paper proposes a channel flow test and develops a correlation between its result and the rheological properties of mortar. The volume-of-fluid simulation for the channel flow test was accomplished, and a numerical database for the correlation was composed. A correlation model to estimate the rheological properties of mortar using the results of the channel flow test as inputs is proposed.

• The Journal of the Korea Contents Association
• /
• v.18 no.3
• /
• pp.369-377
• /
• 2018

EAP, which is operated on the frame of Risk Alarm 4-stage of National Risk Management Guideline, is a critical method in order to promptly respond to disasters. Korea Flood Control Office issues major and moderate flood alarm at each river station by respectively 50% and 70% of design flood discharge in terms of watermark or sea level, however, the criteria deciding major and moderate floods are vague for field managers to control the disaster situations. On the other hand, Japan and USA use river water level as a main criterion in order to classify the stage of flood disaster, which is higher design flood level than Korea. Thus, the authors analyzed domestic and oversea EAP guidelines and suggested improved criteria showing easy display method and raising the criteria of flood level for reflecting more effective action plans through testing a simulation training on the test-bed.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.6
• /
• pp.715-725
• /
• 2000

As a link composition of a double link type level luffing jib crane was determinated through the link composition design, the design to be considered will be computations of the luffing trajectory deviation at the fly jib tip and the required luffing device capacity. This paper is a study regarding the static and dynamic analysis for a mechanism of the crane. The objective of the static analysis is to determinate the capacity and the dimension of luffing device when the crane selfload, rated hoisting load, wind load and inertia force are applied on the crane. The objective of dynamic analysis is to compute the luffing trajectory deviation, velocity and inertia force due to luffing acceleration for each link. All analyses are performed by computer programs. The reliability of the program was checked by results from analyses of the related commercial package. It is expected that the productivity and reliability of the design can be improved by this program which can rapidly and exactly deal with static and dynamic analysis for a given link composition of the crane.

• Journal of Radiation Protection and Research
• /
• v.22 no.3
• /
• pp.143-151
• /
• 1997

As the pulse heights from a NaI(Tl) detector vary with the temperature of the measuring environment a significant change in temperature may affect the energy calibration of the spectrometer. The auto-adjustment of the channel corresponding to a pulse heights can be achieved by introducing an external reference source to compensate the temperature dependency of pulse heights, but unfavorable increases of the Compton continuum are caused due to the external source. In this study, the total absorption peaks dominant in the typical environmental gamma spectrum-239 keV from $^{212}Pb$, 351 keV from $^{214}Pb$, 1460 keV from $^{40}K$ and 2614 keV from $^{208}Tl$ for examples - were used as reference in the correction of energy calibration. With these peaks, the program to calibrate the energy of the s spectrum was developed using Microsoft Visual Basic language. The program developed here was applied to the environmental spectra measured at intervals of 30 minutes in the temperature range of from $-20^{\circ}C$ to $10^{\circ}C$ to demonstrate the validity and applicability. As a result of the test, the correction scheme appeared to be effective in the temperature changes encountered in the usual environment.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.8S
• /
• pp.2608-2619
• /
• 2000

This paper proposes the Handover Scheme for the mobile and describes the result of the performance analysis. In the conventional scheme of handover request, the withdrawal of terminal may occur because handover request is performed based on fixed signal level without considering network load and terminal mobility. The proposed scheme offers the minimization of withdrawal and handover blocking probability by means of the handover request of terminal based on the network load and terminal mobility. Conventional handover scheme has the sequential procedure that network performs resource check and path rerouting on the handover by MT(Mobile Terminal). Proposed handover scheme pre-processes the resource check before the handover request by predicting the handover request timo so that handover latency can be reduced. Moreover, path optimization is executed after the completion of handover in order to reduce handover latency. The rdduction of handover latency prevents the dropping of service by minimizing backward handover blocking. In summary, we propose the prediction of handover request time and decision method based on terminal, validating the performance of proposed scheme considering various cases of simulation.

• The Korean Journal of Community Living Science
• /
• v.15 no.2
• /
• pp.167-177
• /
• 2004

The number of foodborne salmonellosis was estimated by using microbial risk assessment(MRA) methodology and the possibility of application was studied through comparison with previous results. The contamination levels of Salmonella sp. were estimated by using published domestic studies(1997∼2000) and monitoring data (1999∼2001) from food-safety related institutes. Data on food consumption came from the 2001 National Health and Nutrition Survey, and dose-response models from studies in other countries. Simulation results showed that there were 753,368 cases of salmonellosis in Korea in 1 year, which is about 115 times that reported in previous years and lower than the WHO's estimation increase. From these results, microbial risk assessment is likely to be available for estimation of the number of foodborne illnesses and determination of the order of priority in food-safety management. Butthe verification methods are not established and most of the data on contamination levels of foodborne bacteria, food consumption, and dose-response relationships have not been established. In addition, the actual conditions of circulation, storage and cooking must be studied further.

• Korean Journal of Child Studies
• /
• v.23 no.1
• /
• pp.153-171
• /
• 2002

This research addressed the issue of how mothers' representations of attachment are transmitted to children, focusing on post-infancy attachment and on maternal stress as a mediator between mother's attachment style and child attachment security. Fifty-three mother-child dyads participated in a lab visit when the children were 30 months (T1) and 49 months (T2) of age. The Attachment Style Questionnaire and the Parental Stress Inventory were used to measure mothers' characteristics; the Separation-Reunion procedure and classification at T1 and the Attachment Q-set at T2 were used to measure children's attachment security. The models were analyzed by Analysis of Moment Structure Equation. Results confirmed evidence that no direct pathway exists between maternal attachment style and child attachment security : at T1 child attachment security formation was related to maternal stress, but there was no such relationship at T2.