• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.81-86
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• 2011

Polymer-modified cement is the composite material made by partially replacing and strengthening the cement hydrate binders of conventional mortar with polymeric modifiers such as polymer latexes and redispersible polymeric modifiers. It is known that the addition of polymer to cement mortar leads to improved quality, which would be expected to have a high chemical resistance. Therefore, the purpose of this study is to identify the improved chemical resistance, such as low permeability and low ion diffusivity, of the polymer-modified cement as a solidification agent for the radwaste. First, polymer-modified cement specimens by latex modification were prepared according to the polymer content from 0% to 30% to select the optimized polymer content. At those specimens, the water-to-cement (W/C) ratio was maintained to 33% and 50% respectively. After the much curing time, the structural integrity of specimens was evaluated through the compressive strength test and the porosity evaluation by the water immersion method. From the results, 10% of the polymer content at 33% of the W/C ratio was shown to have the most improved quality. Finally, the leaching test referredfrom ANS 16.1 for the specimens having the most improved quality was conducted. Dedicated specimens for the leaching test were then mixed with radioisotopes of $^{60}Co$ and $^{137}Cs$ at the specimen preparation.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.356-367
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• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.183-206
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• 2009

The purpose of this study is to suggest the new strategies for strengthening the competi tiveness of Incheon port. To measure the calling factors and satisfaction of ports, this study developed a list of 24 items using a seven-point Likert scale through the previous literature reviews, pilot test and emerging factors. Factor analysis, regression analysis, one sample T-test, IPA and SPSS were conducted to verify the determinants choosing ports and customer satisfaction. The result of an empirical study revealed that the cargo volume and information system, etc. in Incheon port was evaluated as satisfied factors and berth availability and port charge, etc. as dissatisfied factors. Based on the outcomes of this study, to strengthen the competitiveness of Incheon port, several strategies were advised such as the inducement of North American and European cargo, port infrastructure, dedicated terminal and GTO inducement, hinterland construction, logistics companies inducement and cooperation with neighboring ports.

• Journal of the Korean School Mathematics Society
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• v.4 no.2
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• pp.49-60
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• 2001

This paper is dedicated to the enhancement of the second-grade students of middle school students' understanding of the basic principles and concepts of probability with the help of Web-browser-used WBI programs relating to probability and statistics in teaching them the unit of probability. I have come up with the following research problems with a view to applying and analyzing the findings. (1) A web sites in relation to the learning of probability and statistics is to be developed with the second graders of middle school in mind. (2) Is there any difference between the experiment group exposed to web-sites-aided classes and the control group going through the conventional ways of math classes when the sites is made trial use of \ulcorner (3) What response do the learners show in regard to classes which makes use of the web sites when the sites is applied\ulcorner After making an experiment with the aid of the web sites and teaching plans, I made a measurement and an analysis of the academic achievement of the subjects, their understanding of classes based on the web sites, the concentration of the learners, and their responses relating to the contents of web sites concentrating on probability and statistics. I have come to the following conclusions based on the findings. First there was a significant difference between the classes of honor students and the classes of backward pupils when T-Test was made with regard to the achievement of the subjects who divided into the experiment group and the control group. The former made use of the web sites whereas the latter stuck to the conventional way of teaching math. The former scored higher than the latter. Second, the research based on questionnaire findings shows that the web-site-aided experiment classes proved to be more effective than the traditional control classes. All in all, I think that web-aided classes will have a more positive influence on the students' interest in math and on the scholastic achievement of math than conventional classes.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.56.3-57
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• 2015

As of early 2015, more than 12,000 Near-Earth Objects (NEOs) have been catalogued by the Minor Planet Center, however their observational properties such as broadband colors and rotational periods are known only for a small fraction of the population. Thanks to time series observations with the KMTNet, orbits, optical sizes (and albedo), spin states and three dimensional shapes of asteroids and comets including NEOs will be systematically investigated and archived for the first time. Based on SDSS and BVRI colors, their approximate surface mineralogy will also be characterized. This so-called DEEP-South (Deep Ecliptic Patrol of the Southern Sky) project will provide a prompt solution to the demand from the scientific community to bridge the gaps in global sky coverage with a coordinated use of the network of ground-based telescopes in the southern hemisphere. We will soon finish implementing dedicated software subsystem consisted of automated observation scheduler and data pipeline for the sake of increased discovery rate, rapid follow-up, timely phase coverage, and efficient data analysis. We will give a brief introduction to test runs conducted at CTIO with the first KMTNet telescope in February and March 2015 and experimental data processing. Preliminary scientific results will also be presented.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.678-683
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• 2006

A novel and intuitive way of accessing applications of mobile devices is presented. The key idea is to use grip-pattern, which is naturally produced when a user tries to use the mobile device, as a clue to determine an application to be launched. To this end, a capacitive touch sensor system is carefully designed and installed underneath the housing of the mobile terminal to capture the image of the user's grip-pattern. The captured data is then recognized by a recognizer with dedicated preprocessing and postprocessing algorithms. The recognition test is performed to validate the feasibility of the proposed user interface system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1033-1041
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• 2017

Path travel time based on departure time (PTTDP) is key information in advanced traveler information systems (ATIS). Despite the necessity, forecasting PTTDP is still one of challenges which should be successfully conquered in the forecasting area of intelligent transportation systems (ITS). To address this problem effectively, a methodology to dynamically predict PTTDP between motorway interchanges is proposed in this paper. The method was developed based on the relationships between traffic demands at motorway tollgates and PTTDPs between TGs in the motorway network. Two different data were used as the input of the model: traffic demand data and path travel time data are collected by toll collection system (TCS) and dedicated short range communication (DSRC), respectively. The proposed model was developed based on k-nearest neighbor, one of data mining techniques, in order for the real applications of motorway information systems. In a feasible test with real-world data, the proposed method performed effectively by means of prediction reliability and computational running time to the level of real application of current ATIS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.791-797
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• 2013

This paper proposes a new way to verify the performance of an absorber lined shielded enclosure(ALSE) in accordance with CISPR25, EMC standards dedicated to testing automotive components. CISPR16 requires the use of NSA and VSWR methods to test the performance of a chamber. As for CISPR25, however, there hasn't been standardized ways to verify the performance of ALSE. This paper purports to present an improved method for the verification based on a long-wire antenna method under discussion at CISPR25 JFT. Existing discussions on a long-wire antenna method proposes that an antenna should reach 500 millimeters in length, while this paper adopts the antenna length of 1,700 millimeters. This paper also assesses the effects of matching conditions and studies problems related to methods which have been already proposed and key parameters in order to improve verification methods.

• Journal of the Korean Society of School Health
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• v.31 no.2
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• pp.117-126
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• 2018

Purpose: The leading cause of death among teenagers in Korea is suicide. Also, it is known that mental health of Korean adolescents identified based on the levels of perceived stress or depression is very poor. The purpose of this study was to examine the current status of student mental health programs in Korea and the associated problems and to explore ways to make the programs more effective. Methods: The subjects of the study were a total of 115 school nurses and school counselors in elementary, middle and high schools. The study examined the current status and the associated problems of school mental health programs as well as the needs for teacher training programs related to student mental health. Results: Few mental health programs other than counseling for at-risk students were being carried out. The problems associated with student mental health management were, in terms of management, 'accountability in case of incidents such as student suicide' and 'parents uncooperative in their kid's mental health management (visit to hospital, etc.)' and, in terms of manpower, 'unclear R&R between school nurses and school counselors' and, more fundamentally, 'the lack of human resources.' The needs for teacher training programs related to student mental health were very high and the content required most was 'ways to manage stress of students and teachers themselves,' followed by 'interpersonal conflicts management & conservational skills,' and 'ways to manage student mental illness.' Conclusion: In conclusion, to increase the effectiveness of student mental health programs, we should move on from the current system which focuses only on early discovery and intervention to a more comprehensive system that includes preventive approaches, while having clearer R&R and more workforce dedicated to student mental health programs and attracting more parental cooperation and support.

• Korean Institute of Interior Design Journal
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• v.14 no.5 s.52
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• pp.167-176
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• 2005

Since Korea has already become the 'aging society' and is expected to become the 'aged society' by 2019, development of the facilities and dedicated housing for the senior citizens have become the key issues. The growing population of the senior citizens, changed in the social structure, family type, and the way of living brings a moment to consider the various aspects to support the senior citizens. Now the situation in Korea requires development of congregate housing as a type of residential units for elder who can live at home with some help. Therefore, the purpose of this research was to analyze preference tendency on the interior finishing materials and colors of the congregate housing for the senior citizens who are healthy enough not needing the nursing home. For this research, the preference of 500 Korean pre-senior citizens on the interior finishing materials and colors of congregate housing for the seniors was investigated. The collected data was processed using SPSS 10.0 for Windows regarding frequency, percentage, average, Chi-squared test with cross tabulation. The results are as follows: First, about $60\%$ of the respondents preferred Korean traditional interior image for individual units, and modern interior image for common areas. Second, the respondents preferred wood flooring and wallpaper interior finishing. Third, the respondents Preferred Y, YR color for individual units, and N color for common areas and very pale tone for all spaces. Fourth, the respondents preferred luxury finishing to living room in the all spaces.