• 한국지하수토양환경학회지:지하수토양환경
• /
• 제8권4호
• /
• pp.21-26
• /
• 2003

황과 Powers(2003)는 입도분포와 공극크기분포에 로그분포함수를 적용하여, 입도분포로부터 토양수분특성을 직접 추정하는 간단한 모형을 개발하였다. 본 연구의 목적은 황과 Powers(2003)가 개발한 모형의 추정능력이 토성에 의해 영향을 받는가를 밝히는 것이다. 연구결과, 모형은 토성에 의해 영향을 받았고, 특히 토양내 세립질 분율이 커질수록 모형의 추정능력은 감소하였다. 또한 입도와 공극크기사이의 관계를 비선형으로 가정한 비선형모형이 선형모형보다 토성에 관계없이 그 추정능력이 크게 나타났다.

• KSBB Journal
• /
• 제15권1호
• /
• pp.60-65
• /
• 2000

크로마토그래피의 거동을 수치 모사하기 위하여, retention time method와 moment method에 의해 계산된 파라미터들을 흡착 등온선 모델식에 사용하였다. 이 경우, 이론치와 비교하기 위해서 등용매 조건하게 유기산 이온 크로마토그래피 실험을 수행하였고, 크로마토그램의 거동을 설명하는 수학적 모델로 equilibrium-dispersive model을 사용하였다. Moment method에서는 평균체류시간을 나타내는 1차 모멘트, $m^2$1와 분배 계수 K의 관계로 나타낼 수 있으며, 실험을 통해 분배 계수는 쉽게 구해 질 수 있다. 운전 변수의 변화에 따른 크로마토그램의 특성을 살펴보기 위해서 유기산의 농도, 이동상의 유속, 용리액의 이온 강도 그리고 용질의 주입량을 변화시켜 수치모사를 수행하였다. 각각의 조건에 대해서 크로마토그램은 용질의 농도가 증가할수록, 유속이 증가할수록, 이온 강도가 증가할수록 평균 체류 시간이 감소하고 날카로운 피크를 얻을 수 있었으며, retention time method에서 보다 moment method와 data fitting에 의해 계산된 파라미터들이 실험치와 더 잘 일치함을 볼 수 있었다. 본 연구를 바탕으로, gradient 조건에서 유기산에 대한 이온 크로마토그래피의 거동 연구로 확장할 수 있다.

• 한국응급구조학회지
• /
• 제5권1호
• /
• pp.63-71
• /
• 2001

Retention of CPR knowledge was assessed in a group of 86 police officers who participated in first aid and emergency rescue program on February, 2001 and 3 months later. Police officers were taken written test about CPR knowledge by American Heart Association Guidelines 2000 and competence level. Data were analyzed by Frequency, Percentage, Mean, paired t-test using SPSS program. The results for this study were as follows ; 1. In the post-test, the highest question was a rechecking time of circulation sign(98.8%), the lowest was a check for signs of circulation(17.4%), in 3months later, the highest question was a chest compression(94.2%), the lowest was a check for signs of circulation(1.2%), and a retention of CPR knowledge was a 71.7%. In 3months later, knowledge level was decreased compared to that of post-test(t=-9.09, p=.000). 2. In 3months later, the competence level was decreased compared to that of post-test(t=3.09, p=.003).

• 중환자간호학회지
• /
• 제6권2호
• /
• pp.24-36
• /
• 2013

Propose: This study was to investigate the educational effect and retention of repeated simulation-based basic life support (BLS) training for nursing students. Methods: A comparison group design with pretest and posttest was used. A total of 35 nursing students (18 for the experimental group, 17 for the control group) participated in the study. A repeated simulationbased BLS training program which include a lecture, skills training, and two repeated sessions of simulation practice and debriefing was provided twice for experimental group. Knowledge, self-efficacy, and skill performance of cardiopulmonary resuscitation (CPR) were measured three times: at baseline, week 2, and week 6. Descriptive analysis, repeated measures ANOVA, and t-test were used for data analyses. Results: Knowledge, self-efficacy and skill performance of CPR were not significantly changed by group assignment, by the time, and interaction of group by time. Effectiveness of intervention was not maintained until Week 6. Conclusion: The results suggest that the timing of repeat education, total training time, and students' mastery of CPR performance should be considered when developing simulation-based programs to improve and maintain students' CPR knowledge, self-efficacy, and skill performance.

• Geomechanics and Engineering
• /
• 제20권5호
• /
• pp.411-420
• /
• 2020

Numbers fitting-curve equations have been proposed to predict soil-water retention curve (SWRC) whose parameters have no definitude physical meaning. And these methods with precondition of measuring SWRC data is time-consuming. A simplified directly method to estimate SWRC without parameters obtained by fitting-curve is proposed. Firstly, the total SWRC can be discretized into linear segments respectively. Every segment can be represented by linear formulation and every turning point can be determined by the pore-size distribution (PSD) of Mercury Intrusion Porosimetry (MIP) tests. The pore diameters governing the air-entry condition (AEC) and residual condition (RC) can be determined by the PSDs of MIP test. The PSD changes significantly during drying in SWR test, so the determination of AEC and RC should use the PSD under corresponding suction conditions. Every parameter in proposed equations can be determined directly by PSD without curve-fitting procedure and has definitude physical meaning. The proposed equations give a good estimation of both unimodal and bimodal SWRCs.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
• /
• pp.216-219
• /
• 2006

Water retention curve (WRC), one of soil hydraulic properties, is often approximated by property-transfer models (PTMs). Using the PTMs, we can estimate the WRCs from other physical properties such as particle-size distribution (PSD). The objective of this work was to investigate the performance of two PTMs with different origins for numerical simulations on transport of Benzo[a]pyrene in a soil. To do this, we chose both PTMs with different origins, i.e., (1) the lognormal distribution model (L anti NL models), and (2) the modified $Kov\'{a}cs$ model (MK model). The MK model showed tile worse performance in estimation of the WRCs. When transport of B[a]P was simulated, the MK model predicted to move farther than the L and NL models did, indicating that transport of B[a]P in a soil can be greatly influenced by the choice of PTMs.

• 한국치위생학회지
• /
• 제16권1호
• /
• pp.45-52
• /
• 2016

Objectives: The purpose of the study was to investigate the cumulative dental caries rate of pit and fissure sealant in community public health program from 2005 to 2008 follow-up. Methods: The subjects were 4,768 students of 34 elementary schools in Gimcheon. The survey included direct oral examination and cumulative retention rate of pit and fissure sealant from 2005 to 2008. Data were analyzed using PASW statistical package version 18.0 and the level of significance was set at p<0.05. Results: The cumulative retention rate of sealant was 18%, 25%, and 33% after 1 year, 2 years, and 3 years, respectively. In addition, the cumulative retention rate of lower teeth was higher than that of upper teeth. Cumulative dental caries rate increased in sealed group and no sealed group. The cumulative dental caries rate decreased owing to tooth brushing frequency in sealed group and no sealed group. Conclusions: Regular and timely tooth brushing can maintain good oral health condition after tooth sealing. The school based oral health education can prevent loss of sealant and secondary caries.

• 한국전문물리치료학회지
• /
• 제12권1호
• /
• pp.36-44
• /
• 2005

The purpose of this study was to examine the effects of self-controlled learning using the (KR) feedback schedule versus the yoked KR on the acquisition and retention of balance training for individuals with hemiplegics. Sixteen hemiplegics were randomly assigned to either a self-controlled or yoked KR group. All subjects were ambulatory with or without an assistive device. The self-controlled group was provided with feedback whenever they requested it, whereas the yoked group had no influence on the feedback schedule. All subjects performed 10 acquisition trials and 10 retention trials the day after acquisition. The data were analyzed using an independent t-test and a Mann-Whitney U test. Participants in the self-controlled group achieved significantly more effective learning than the yoked group during the acquisition and retention test except anterior/posterior (AP) body sway. These results suggest that a feedback schedule which is controlled by the individuals with hemiplegics may be more effective in balancing training than a yoked KR which is not controlled by the subject.

• 한국시뮬레이션학회논문지
• /
• 제9권4호
• /
• pp.51-58
• /
• 2000

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. The novel junction process scheme in sub-micron DRAM cell with STI(Shallow Trench Isolation) has been investigated to improve the tail component in the retention time distribution which is of great importance in DRAM characteristics. In this' paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced ${\Delta}Rp$ (projected standard deviation) increase using buffered N-implantation with tilt and 4X(4 times)-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N-concentration which is Intentionally caused by ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation. And also, we suggest the least requirements for adoption of this new implantation scheme and the method to optimize the key parameters such as tilt angle, rotation number, Rp compensation and Nd/Na ratio. We used MEDICI Simulator to confirm the junction device characteristics. And measured the refresh time using the ADVAN Probe tester.

• 대한간호학회지
• /
• 제50권1호
• /
• pp.1-13
• /
• 2020

Purpose: The purpose of this study was to construct and test a structural equation model on nursing work outcomes based on Youssef and Luthans' positive psychological capital and integrated conceptual framework of work performance. Methods: This study used a structured questionnaire administered to 340 nurses. Data were analyzed using structural equation modeling. Results: Positive psychological capital showed indirect and direct effects on job satisfaction, retention intention, organizational citizenship behavior, and nursing performance. While, the nursing work environment had direct and indirect effects on job satisfaction and nursing performance, it only had indirect effects on intention to work and organizational citizenship behavior. Additionally, a mediating effect on retention intention and organizational citizenship behavior was found between job satisfaction and nursing performance variables. Conclusion: The nursing organization needs to build a supportive work environment and reinforce positive psychological capital to improve nursing performance. Additionally, it needs to actively manage the necessary parameters involved in the stages of job satisfaction, retention intention, nursing performance, and organizational citizenship behavior of nurses. The findings propose the continuous management of nursing personnel based on nurses' attitude outcome, behavioral intention, behavioral outcome, and stage of role performance.