• Title/Summary/Keyword: Diffusion models

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Development of "Drink Smart" Alcohol Education Program for University Students: Application of the Intervention Mapping and Transtheoretical Model (대학생 절주교육 프로그램(과음없는 캠퍼스 만들기) 개발: Intervention Mapping과 Transtheoretical Model의 적용)

  • Kim, Hye-Kyeong;Kim, Myung;Lee, Eun-Hee;Kwon, Eun-Joo;Cho, Han-Ik
    • Korean Journal of Health Education and Promotion
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    • v.28 no.5
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    • pp.145-160
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    • 2011
  • Objectives: This study attempted to apply the Intervention mapping and Transtheoretical models to develop a program to promote moderate alcohol drinking in university students. Methods: Surveyed data from 1,137 university students were analyzed to identify personal and environmental determinants for alcohol drinking. Based on these determinants, program objectives were established. Crossing the objectives with related important determinants resulted in matrices of learning objectives for which educational strategies were developed. Subsequently, an intervention program were designed to achieve those objectives. Results: Identified personal determinants included awareness, attitudes, self-efficacy and behavioral skills. Environmental determinants were binge drinking behaviors of family members and peers, and social pressure for drinking. Program, impact and learning objectives were developed to change the identified determinants. Program activities included provision of information on positive and negative consequences of binge drinking, opportunities for assessing one's drinking pattern, increasing outcome expectancies of and skill building for monitoring drinking, resisting peer pressure and managing stress. To facilitate adoption and maintenance of the program, an intervention diffusion plan was suggested. An evaluation plan was developed by utilizing RE-AIM framework. Conclusions: In order to expand evidence bases for effective theory-based programs, the developed program should be tested in diverse university settings.

Analysis of Debris Flow Disaster Area according to Location Change of Check Dam using Kanako-2D (Kanako-2D를 이용한 사방댐 위치 변화에 따른 토석류 피해지 분석)

  • Kim, Young Hwan;Jun, Kye-Won
    • Journal of the Korean Society of Safety
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    • v.33 no.1
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    • pp.128-134
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    • 2018
  • With the increase in frequency of typhoons and heavy rains following the climate change, the scale of damage from the calamities in the mountainous areas has been growing larger and larger, which is different from the past. For the case of Korea where 64% of land is consisted of the mountainous areas, establishment of the check dams has been drastically increased after 2000 in order to reduce the damages from the debris flow. However, due to the lack of data on scale, location and kind of check dams established for reducing the damages in debris flow, the measures to prevent damages based on experience and subjective basis have to be relied on. Under this study, the high-precision DEM data was structured by using the terrestrial LiDAR in the Jecheon area where the debris flow damage occurred in July 2009. And, from the numerical models of the debris flow, Kanako-2D that is available to reflect the erosion and deposition action was applied to install the erosion control facilities (water channel, check dam) and analyzed the effect of reducing the debris flow shown in the downstream.After installing the erosion control facilities, most of debris flow moves along the water channel to reduce the area to expand the debris flow, and after installing the check dam, the flow depth and flux of the debris flow were reduced along with the erosion. However, as a result of analyzing the diffusion area, flow depth, erosion and deposition volume of the debris flow generated from the deposition part after modifying the location of the check dams with the damages occurring on private residences and agricultural land located on the upstream area, the highest reduction effect was shown when the check dam is installed in the maximal discharge points.

Effects of Action Oriented Breast Self-examination(BSE) Education on Knowledge, Self-efficacy, and Performance Competence in Nursing Students (행위중심적 유방자가검진 교육이 간호학생의 지식, 자기효능감 및 수행능력에 미치는 효과)

  • Park, So-Mi;Hur, Hea-Kung;Park, Mi-Jeong;Song, Hee-Young
    • Women's Health Nursing
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    • v.12 no.1
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    • pp.47-52
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    • 2006
  • Purpose: This study was undertaken to test effects of action oriented BSE education on knowledge, selfefficacy, and performance competence in nursing students. Methods: A non-equivalent pre-posttest of time serial quasi-experimental design was used to prevent diffusion of the experiment. Out of 53 nursing students selected by convenient sampling in the third grade at a nursing college, 27 students were randomly assigned to the control group and were first given a traditional lecture on BSE. For the experimental group of 26 students action oriented BSE education consisted of lectures, demonstrations with breast models, and BSE skill practice by micro teaching. Results: There was no significant difference in general and BSE-related characteristics between the two groups. Scores of the experimental group in knowledge, self-efficacy, and performance after the intervention were significantly higher than those of the control group. Conclusions: Results showed that action- oriented BSE education was effective in increasing knowledge, self-efficacy and performance competence in nursing students. Education for students should incorporate strategies reinforcing confidence by practicing actual BSE skills as well as acquiring knowledge of BSE, so that students can become competent and practical cancer prevention educators.

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Hydrologic Response Analysis Considering the Scale Problem : Part 1. Derivation of the Model (규모문제를 고려한 수문응답의 해석 : 1. 모형이론의 유도)

  • 성기원;선우중호
    • Water for future
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    • v.28 no.4
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    • pp.185-194
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    • 1995
  • The objective of this study is to explore scale problem and to analyze the relations between scale and geomorphologic parameters of the rainfall-runoff model. Generally, measurement and calculation of geomorphologic parameters rely on and are sensitive to the resolution of source information available. Therefore, rainfall-runoff models using geomorphologic parameters should take account of the effects of the map scale used in their development. The derived rainfall-runoff model considering scale problem in this research is the GIUH type model, that is a basin IUH consisting of the channel network response and hillslope response. The cannel network response is computed by means of the diffusion analogy transformed from linearized St. Venant equation and hillslope response is calculated by 2-parameter gamma distribution function. Representing geomorphologic structure of the channel network and initial distribution of its response is width function. This width function is derived by fractal theory and Melton's law to consider scale problems and is weighted by the source location function (SLF) proposed in this research to increase the applicability.

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Crystallization Mechanism of Lithium Dislicate Glass with Various Particle Sizes (Lithium disilicate 유리의 입자크기에 따른 결정화 기구)

  • Choi, Hyun Woo;Yoon, Hae Won;Yang, Yong Suk;Yoon, Su Jong
    • Korean Journal of Materials Research
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    • v.26 no.1
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    • pp.54-60
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    • 2016
  • We have investigated the crystallization mechanism of the lithium disilicate ($Li_2O-2SiO_2$, LSO) glass particles with different sizes by isothermal and non-isothermal processes. The LSO glass was fabricated by rapid quenching of melt. X-ray diffraction and differential scanning calorimetry measurements were performed. Different crystallization models of Johnson-Mehl-Avrami, modified Ozawa and Arrhenius were adopted to analyze the thermal measurements. The activation energy E and the Avrami exponent n, which describe a crystallization mechanism, were obtained for three different glass particle sizes. Values of E and n for the glass particle with size under $45{\mu}m$, $75{\sim}106{\mu}m$, and $125{\sim}150{\mu}m$, were 2.28 eV, 2.21 eV, 2.19 eV, and ~1.5 for the isothermal process, respectively. Those values for the non-isothermal process were 2.4 eV, 2.3 eV, 2.2 eV, and ~1.3, for the isothermal process, respectively. The obtained values of the crystallization parameters indicate that the crystallization occurs through the decreasing nucleation rate with a diffusion controlled growth, irrespective to the particle sizes. It is also concluded that the smaller glass particles require the higher heat absorption to be crystallized.

Three Dimensional Mathematical Simulation for Predicting the Shelf Life of Tofu Packaged in a Semi-rigid Plastic Container (플라스틱 용기 포장 두부의 유통기간 예측을 위한 3차원 수치모사)

  • Kim, Jai-Neung;Lee, Youn-Suk
    • Korean Journal of Food Science and Technology
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    • v.41 no.3
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    • pp.272-277
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    • 2009
  • In this research, three dimensional mathematical models were developed to predict the shelf life of tofu packaged in a semi-rigid plastic container. A model combining oxygen transfer through the package and oxygen consumption within the package was considered. According to the results, the model simulations estimated that the number of microorganisms in the filled water was higher than that in the tofu, suggesting the shelf life of packaged tofu was not affected by the number of microorganisms in the tofu product, but rather by the number of organisms in the filled water. Additionally, the effects of the physical properties of the packaging material, such as oxygen permeability through the package, oxygen diffusion coefficient, the initial oxygen concentration in the filled water, and the depth of the filled water in the packaged tofu, were also observed.

Estimation of Surface Layer Heat Flux Using the UHF Sensor Installed on UAV (UHF 센서 탑재 UAV를 이용한 지표층 열 플럭스 산출)

  • Kim, Min-Seong;Kwon, Byung Hyuk;Yoon, Hong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.1
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    • pp.265-276
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    • 2018
  • Observation and data analysis techniques have been developed for observational blind areas in the lower atmosphere that are difficult to be monitored with fixed equipment on the ground. The vertical data of temperature and relative humidity are remotely collected by the UHF radiosonde installed on UAV and compared with the data measured in the 10 m weather tower. From the validated vertical profile, extrapolated surface temperature and the bulk transfer method were used to estimate the sensible heat flux depending on the atmospheric stability. Compared with the sensible heat flux measured by the 3-dimensional ultrasonic anemometer on the ground, the error of the sensible heat flux estimated was 23% that is less than the range of 30% allowed in the remote sensing. Estimated atmospheric boundary layer height from UAV sensible heat fluxes can provide useful data for air pollution diffusion models in real time and economically.

A Simple Model for Dispersion in the Stable Boundary Layer

  • Kang Sung-Dae;Kimura Fujio;Lee Hwa-Woon;Kim Yoo-Keun
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.1
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    • pp.35-43
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    • 1997
  • Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are 'A' and 'B' at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.

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An improved 1D-model for computing the thermal behaviour of concrete dams during operation. Comparison with other approaches

  • Santillan, D.;Saleteb, E.;Toledob, M.A.;Granados, A.
    • Computers and Concrete
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    • v.15 no.1
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    • pp.103-126
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    • 2015
  • Thermal effects are significant loads for assessing concrete dam behaviour during operation. A new methodology to estimate thermal loads on concrete dams taking into account processes which were previously unconsidered, such as: the evaporative cooling, the night radiating cooling or the shades, has been recently reported. The application of this novel approach in combination with a three-dimensional finite element method to solve the heat diffusion equation led to a precise characterization of the thermal field inside the dam. However, that approach may be computationally expensive. This paper proposes the use of a new one-dimensional model based on an explicit finite difference scheme which is improved by means of the reported methodology for computing the heat fluxes through the dam faces. The improved model has been applied to a case study where observations from 21 concrete thermometers and data of climatic variables were available. The results are compared with those from: (a) the original one-dimensional finite difference model, (b) the Stucky-Derron classical one-dimensional analytical solution, and (c) a three-dimensional finite element method. The results of the improved model match well with the observed temperatures, in addition they are similar to those obtained with (c) except in the vicinity of the abutments, although this later is a considerably more complex methodology. The improved model have a better performance than the models (a) and (b), whose results present larger error and bias when compared with the recorded data.

Numerical Study of Flow Pattern and Drug Deposition in Drug-Eluting Stent (약물분출 스텐트 주위 유동형태와 약물침전에 대한 수치해석)

  • Seo, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.1053-1060
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    • 2011
  • This study is performed to determine the drug concentration profiles of drug-eluting stents (DES) for an ideal circular ring stent and intertwined stent models for various Reynolds numbers (Re = 200, 400, and 800). The Navier.Stokes equations coupled with the advection-diffusion equation are solved numerically in order to determine how the flow patterns and drug deposition are affected in the in-stent and post-stent regions where flow separation and recirculation occur. The presence of DES within the arterial segment affects the local drug distribution in the flow field. As a result, the drug concentration for the intertwined stent is higher over the in-stent region in comparison with the ideal stents. For a given stent geometry, the local drug concentration in the in-stent region decreases with Reynolds number, while for a given Reynolds number, the local drug concentration is relatively insensitive to the stent geometry. The results show that drug concentration along the arterial wall is significantly higher within the in-stent and post-stent regions for the intertwined stent geometry than for the ideal stent geometries.