• Advances in Energy Research
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• v.4 no.4
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• pp.299-323
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• 2016

Cylindrical parabolic solar concentrators of small concentration ratio are attractive options for working temperatures around $120^{\circ}C$. The heat gained can be utilized in many applications such as air conditioning, space heating, heating water and many others. These collectors can be easily manufactured and do not need to track the sun continuously. Using a heat pipe as a solar absorber makes the system more compact and easy to install. This study is devoted to modeling a system of cylindrical parabolic solar concentrators of small concentration ratio (around 5) fitted with a heat pipe absorber with a porous wick. The heat pipe is surrounded by evacuated glass tube to reduce thermal losses from the heat pipe. The liquid and vapor flow equations, energy equation, the internal and external boundary conditions were taken into consideration. The system of equations was solved and the numerical results were validated against available experimental and numerical results. The validated heat pipe model was inserted in an evacuated transparent glass tube as the absorber of the cylindrical parabolic collector. A calculation procedure was developed for the system, a computer program was developed and tested and numerical simulations were realized for the whole system. An experimental solar collector of small concentration, fitted with evacuated tube heat pipe absorber was constructed and instrumented. Experiments were realized with the concentrator axis along the E-W direction. Results of the instantaneous efficiency and heat gain were compared with numerical simulations realized under the same conditions and reasonably good agreement was found.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.345-356
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• 2013

Numerical simulation on rock cutting by a TBM disc cutter was carried out using SPH (Smoothed Particle Hydrodynamics) code. AUTODYN3D, a commercial software program based on finite element method, was used in this study. The three-dimensional geometry of a disc cutter and a rock specimen were modeled by Lagrange and SPH code respectively. The numerical simulation was carried out for Hwangdeung granite for 10 different cutting conditions. The results of the numerical simulation, i.e. the relation between cutter force and failure behavior, had a good agreement with those from LCM test. The cutter forces measured in the numerical simulation had 10% deviation from the LCM test results. Moreover, the optimum cutter spacing was almost identical with the experimental results. These results indicate that SPH code can be successfully used had applicability for simulation on rock cutting by a TBM disc cutter. However, further study on Lagrange-SPH coupled modelling would be necessary to reduce the computation time.

• Journal of Korean Home Economics Education Association
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• v.13 no.3
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• pp.131-146
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• 2001

The purpose of this study were to develop cooperative learning lesson plan for middle school home economics class and to identify the effect of cooperative learning on students\` self-esteem. The content of lesson was chosen from the food and nutrition section of home economics textbooks for middle school. The main structure of the lesson plan stems from $\boxDr$Lesson Plan Guide of Structuring Cooperative Learning Lesson Plan for Teachers$\boxUl$ by D. Johnson. R Johnson and E. Holubec. Various kinds of references including media reading materials cooperative group activity reports and cooperative group activity checking lists were newly developed according to the content of lesson. Eight hour lesson plans were developed and applied to 2nd grade middle school students and pre-test and post-test were taken to test the effect of Johnson\`s cooperative learning method on students\` self-esteem. Students at a Middle School located in Seoul were divided into two grouts, the three classes as experimental group and the other three classes as control group. The data were analyzed by ANCOVA using SPSS/WIN program. As a result, the hypothesis that the degree of self-esteem of the experimental group is higher than that of control group was adopted (P.(001). Among the sub-factors of self -esteem. the global self-esteem and the social-peer self-esteem scores of the experimental group were higher than that of the control group(p.(001 each). but the school-academic self-esteem score was not different (p> .05) According to the post-experiment free-style report. student as a dynamic subject could get initiatives and interests in home economics class more effectively by cooperative learning. Therefore, it could be said that cooperative learning has positive effect on the promotion of students\` self-esteem and is considered to be a good teaching method of home economics subject.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.495-498
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• 1995

Records taken on 372 young beef bulls tested at the Ellerslie Bull Test Station, Alberta, Canada from November 1981 to April 1987 were analyzed to quantify the effects of age of dam, on-test age, on-test liveweight and herd of origin of bull on feed efficiency (feed/gain, kg/kg) in the test period (n = 231) and ultrasonic measurement of bakcfat thickness (mm) at the end of the test (n = 372). The reduction in $R^2$ due to each influencing factor (i.e. the variation accounted for by the factor) was used to indicate the importance of the influencing factor. Age of dam and on-test age of bull were not important factors on feed/gain and ultrasonic backfat thickness, as they accounted for less than 0.5% of the variation in feed/gain and ultrasonic backfat thickness, respectively (p > 0.1). On-test liveweight had some influence on feed/gain and ultrasonic backfat thickness, accounting for 3.5% (p < 0.01) and 0.4% (p < 0.05) of the total variation, respectively. The regression coefficients of feed/gain and ultrasonic backfat thickness on on-test liveweight were 0.016 (kg/kg)/kg and .013 mm/kg, respectively, both being significant (p < 0.05), indicating that lighter bulls entering the test were generally more efficient in feed utilization in the test period and had less backfat at the end of the test than heavier entering bulls. Herd of origin of bull accounted for a substantial amount of the total variation (> 16%) in feed/gain and ultrasonic backfat thickness (p = 0.08), indicating that a prolonged aqjustment period was needed to reduce the influence of herd of origin when assessing aggregate genetic merit of beef bulls for growth rate, feed efficiency and lean meat production using a central station performance testing program.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.162-165
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• 2003

Transformation of Fuji apple (Malus domestica 'Fuji') was performed using Agrobacterium tumefaciens harboring a coat protein (CP) gene of Cucumber mosaic virus (CMV). A plasmid DNA containing the virus CP and NPT II genes was introduced into the loaves of apple by th e Agrobacterium - mediated transformation procedure. Regenerated transformants of the apple were obtained by kanamycin resistance conferred by the introduced NPT II gene. PCR analysis showed that 3 out of 20 putatively selected R0 plant lines contain the CMV-CP gene. Nine putative transgenic lines out of 20 lines were investigated with the PCR analysis; 5 regenerants produced a 450 bp DNA band and 3 regenerants showed a 671 bp DNA band for the NPT II and CMV-CP genes, respectively. Southern hybyidization results demonstrate the successful integration of the CMV-CP gene into the genome of the apple. This is the first report on the generation of useful vius resistance source of transgenic apple for molecular breeding program.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.113-128
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• 1990

This study was designed to identify the problems in teaching housing course at secondary level. The main tasks of Investigation were to: (1) identify appropriate housing concepts to be taught at secondary school, (2) determine the Kinds of media and methods used for teaching housing course at secondary school. The questionnaire was divided Into three sections: (1) the teacher`s background, (2) the teacher`s opinion regarding the importance of various housing topics to teaching. (3) what type of media and methods were used by teachers. Data were collected In Pusan during November 1959. The Sample, 150Home Economics teacher was randomly selected from secondary school list in Pusan. Responses from 122 Home Economics teachers, were processed by the S.P.S.S. computer program. and N.P.E.R.C using for frequency counts and percentages to analyze the data from all three sections of questionnaire. One-way Analysis of Variance and Newman-kuels Multiple Comparison test were used to reject or accept the hypotheses. The major findings were: (1) there were some difference between teachers` opinions regarding the importance of various housing topics to teach and teachers actural practice of teaching housing concepts and topics, (2) teachers taught housing concepts which were important to teach by their opinion, even though those concepts were neglected in textbook, (3) teachers did not use a various of media and methods for their teaching housing class, (4) the important reasons given why the teachers for not using the various media and methods were because of undesirable educational situations, and (5) there were some significant differences between teachers` background and teachers` opinion regarding importance of teaching topics in housing class at secondary school, using media and methods.

• Journal of the Korean Society of School Health
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• v.29 no.1
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• pp.1-10
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• 2016

Purpose: The purpose of this study was to identify the mediating effect of stress coping type and self-esteem between life stress and suicidal ideation in nursing college students. The research design was descriptive study. Methods: A set of self-reported questionnaires was completed by 197 nursing college students, including demographic characteristics, life stress, stress coping type, self-esteem, and suicidal ideation. Data was analyzed using t-test, ANOVA, $Scheff{\acute{e}}^{\prime}s$ test, correlation analysis, and regression analysis for mediating effect by SPSS ver. 22. Results: The mean age was 20.9 years. The mean scores were 2.4, 3.6, and 1.7 out of 5 Likert scales for items of life stress, self-esteem, and suicidal ideation, respectively. The mean score for stress coping type was 2.36 out of 4 Likert scales. There was a positive correlation between suicidal ideation and life stress related to tasks, life stress related to interpersonal relationship, and emotion-focused coping of stress coping type (r=.537, p<.01); while a negative correlation between self-esteem and suicidal ideation. emotional-focused coping of stress coping type had a partial mediating effect between life stress related to tasks and suicidal ideation. Also, self-esteem had a partial mediating effect between life stress related to tasks and suicidal ideation as well as between life stress related to interpersonal relationship and suicidal ideation. Conclusion: Based on the finding of this study, it is necessary to apply various program to stress coping skill and self-esteem in order to reduce suicidal ideation in nursing college students.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.107-115
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• 2006

The existing DLC system functionally has two defects. One is it has to be controlled by operators whenever customer's portion of loads are increased more than predefined objected load. Therefore, it may be possible for propagating uncontrolled loads if operators make a mistake. The other one is that currently used DLC algorithm is usually focused on ON/OFF load control not concerning about reliving participated customer's inconvenience. Therefore, that is a major obstacle to attract customer participating in demand response program. This paper represents direct load control system using active database. By using active database, DLC system can control customer's load effectively without intervening of operator. And by using dynamic programming based on the order of priority for DLC algorithm, it is possible to maximize participating customer's satisfaction.

• Structural Engineering and Mechanics
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• v.40 no.1
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• pp.85-103
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• 2011

Integration of finite element analysis (FEA) software into various software platforms is commonly used in coupling systems such as systems involving structural control, fluid-structure, wind-structure, soil-structure interactions and substructure method in which FEA is used for simulating the structural responses. Integrating an FEA program into various other software platforms in an efficient and simple way is crucial for the development and performance of the entire coupling system. The lack of simplicity of the existing integration methods makes this integration difficult and therefore entails the motivation of this study. In this paper, a novel practical technique, namely CS technique, is presented for integrating a general FEA software framework OpenSees into other software platforms, e.g., Matlab-$Simulink^{(R)}$ and a soil-structure interaction (SSI) system. The advantage of this integration technique is that it is efficient and relatively easy to implement. Instead of OpenSees, a cheap client handling TCL is integrated into the other software. The integration is achieved by extending the concept of internet based client-server concept, taking advantage of the parameterization framework of OpenSees, and using a command-driven scripting language called tool command language (TCL) on which the OpenSees' interface is based. There is no need for any programming inside OpenSees. The presented CS technique proves as an excellent solution for the coupling problems mentioned above (for both linear and nonlinear problems). Application examples are provided to validate the integration method and illustrate the various uses of the method in the civil engineering.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.710-718
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• 2008

This paper presents a simple and fast approach to plan the arrangement of supports and to do a ship docking analysis. The unpredicted structural damages often happen from a docking works as the size of ships are getting larger and larger. In docking a ship, excessive reaction forces from supports are primary causes of the structural damage. The grillage analysis method is employed to simply calculate only the reaction forces at supports. The grillage modeling strategies are proposed to improve the accuracy. In this paper, the results obtained by the proposed approach are compared with those of the current whole-ship FEA for typical types of ships. Comparison shows that the results from the present grillage approaches are reasonably in a good agreement with the 3-D full F.E one. Finally, an integrated program developed for the ship docking analysis is described.