• Journal of Elementary Mathematics Education in Korea
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• v.17 no.2
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• pp.225-243
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• 2013

This study was to analyze the effects of basic computational abilities using G-learning contents, which was developed for mathematically slow learners. The participant students were 146 mathematically slow learners in grade 3-6 in Seoul. The researchers analyzed the difference between pre and post test scores to check their effectiveness. Also, teachers and parents as well as students responded survey items to check dispositions and satisfactions towards the program. The research results showed that the application of the G-learning contents on basic computation areas was effective to develop students' basic computational skills. In addition, students also showed that they were satisfied studying basic computations with the G-learning contents. They had increased beliefs about and decreased difficulties in mathematics. Parents and teachers also had satisfactions in using the G-learning programs in spite of some negative effects such as errors in the contents, use of computers, and concentration on the game itself. For the improvement of G-learning contents, we need to keep studying on G-learning contents with wide range of areas and long term studies.

• Journal of Science Education
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• v.37 no.2
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• pp.405-415
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• 2013

The purpose of this study was to investigate high school students in natural science track and engineering major university students' perceptions about the writing and composition education. A total of 318 high school students in natural science track from two high schools in a metropolitan area and 447 university students majoring in engineering from three universities participated in the survey and asked to response their perceived status and needs of writing education for science-engineering track. The survey instrument, developed by Lee et al.(2009), was used for this study. The data was analyzed through the SPSS 18.0 program for Windows for Multiple Response Frequency Analysis, Descriptive Statistics, Independent Samples t-test, and One-way Analysis of Variance. The results indicated that high school students relatively perceived that writing education was less necessary compared to university students. In addition, high school students found writing less difficult than university students do. In related to studying their experience with writing and composition education, almost no high school students have taken writing classes and university students have taken an average of one class. Most university students who took writing classes took basic writing classes that were not programmed for students in Science and Engineering. In the basic survey to revitalize writing and composition education for Science and Engineering students in different majors, the level of writing and composition education required by students in each major was different. Writing was considered most necessary for students majoring in Chemical Engineering, followed by students majoring in Mechanical Engineering and Electronic Engineering. The study of writing and composition education for high school and college should extend to studies on teachers or professors who teach writing, studies on contents and methods of writing education, and studies on the development of writing programs for different majors in university.

• Journal of Science Education
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• v.41 no.1
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• pp.80-97
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• 2017

The purpose of this study was to develop understanding-oriented materials based on backward course design model and analyze their effects on 'biology and environment' unit of elementary school science. Backward Design starts from a specification of learning outcomes and decisions on methodology and syllabus are developed from the learning outcomes. This method has a strength maintaining consistency between educational contents-evaluation-learning activities and also promoting student's authentic understanding. The 78 students 6th graders participated in this experiments. Data was collected using project activities, the science academic emotion scale and academic achievement. The collected data was analyzed by t-test and ANCOVA analysis using the SPSS 23 statistical program. The following major conclusions were drawn on the basis of data analysis. First, the experimental group showed a relatively accurate understanding of the contents of science but they could not produce creative output in two project activities. Second, the interaction effect of the instruction based on backward curriculum design and science academic emotion was not significant statistically. Third, the experimental group showed a significant improvement in the academic achievement of 'biology and environment' unit.

• Journal of Hospice and Palliative Care
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• v.12 no.2
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• pp.80-87
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• 2009

Purpose: The purposes of this study were to identify the types of widow's bereavement experience and understand the nature of it's bereavement by using Q-methodological approach. Methods: Contents Q sample included 46 statements obtained from literatures and interviews with 5 widows. P sample consisted of 13 widows who bereaved within 2 years. The data were collected from October 2004 to December 2006 and analyzed using Quanal program. Results: Two types of widow's experience were found. Type 1 was characterized by loss suffering, and type 2 was characterized by acceptance and adaptation Conclusion: Widows were found to experience different types of bereavement. Therefore, bereavement care team should assess the types of suffering pain and provide appropriate care to the widows. Also, need to be developed programs to relieve or prevent suffering of bereavement.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.464-472
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• 1996

The mechanism of thin-film formation by Ionized Cluster Beam Deposition(ICBD) was investigated. A simulation program based on the Monte-Carlo method was developed in order to investigate the effects of the acceleration voltage, substrate temperature, activation energy for the surface migration, and critical nuclei size on grain size and surface roughness. Studies of the effect of kinetic energy of clusters on the film formation processes revealed that high acceleration voltage enhanced the surface-migration of adatoms and made it easier for an epitaxial film to be formed. The relaxation time of kinetic energy of adatoms increased with the substrate temperature, which in turn increased the grain size of the crystalline film. This effect was more clearly distinguished when the critical nuclei size was large. The surface-migration activation energy was found to affect the interaction between the adatoms and the substrate and thus the relaxation time of kinetic energy. Investigations of the surface roughness revealed that the acceleration voltage, the substrate temperature, and the surface-migration activation energy exerted a collective effect on the morphology of the film surface.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.143-156
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• 2019

Discussion on OTT regulation has become fiercer, as OTT services' impacts on the global and domestic media market have been exponentially growing. In South Korea, it is argued that, on the basis of the similarity between television program and OTT's video content, OTT needs to be regulated in order to protect fair competition and to control sociocultural effects. In many of the discussions, developed countries' cases have been used for supporting OTT regulation. In this paper, we first analyzed the global OTT market trends based on our own categorization of OTT services. then we assessed the validity of the application of the foreign cases in the current OTT regulation debates in Korea. We proposed six OTT types (aggregation, mediation, mediation-aggregation, multi-screen, outlet, and outlet-linear) simultaneously considering service operator' origin, business model, content format, and content delivery. These services have been consistently evolving, and the OTT market has been increasingly competitive especially around content differentiation. Regulators must be wary of hastily introducing competition regulation to the dynamically innovating OTT market. The foreign cases, including the US, EU, the UK, and Japan, hardly seem to be appropriate bases for strengthening OTT regulation. Rather, they were focused more on promoting competition in the domestic media market and enriching the content ecosystem. Therefore, we need to consider revision of the outdated media regulation frameworks instead of fitting OTT under them, and to recognize the priority of securing practical jurisdiction on global service providers before capturing local players into the conventional regulation systems.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.105-117
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• 2019

Bitcoin, which can be classified as a cryptocurrency, has attracted attention from various industries because it is an innovative digital currency and the beginning of a Blockchain system. However, as the research on Bitcoin progressed, several security vulnerabilities and possible attacks were analyzed. Among them, the security problem caused by the transparency of the Blockchain database prevents the Blockchain system from being applied to various fields. This vulnerability is further classified as the weak anonymity of participating nodes and privacy problem due to disclosure of transaction details. In recent years, several countermeasures have been developed against these vulnerabilities. In this paper, we first describe the main features of the public and private Blockchain, and explain privacy, unlinkability and anonymity. And, three public Blockchain platforms, Dash, Zcash and Monero which are derived from Bitcoin, and Hyperledger Fabric which is a private Blockchain platform, are examined. And we analyze the operating principles of the protocols applied on each platform. In addition, we classify the applied technologies into anonymity and privacy protection in detail, analyze the advantages and disadvantages, and compare the features and relative performance of the platforms based on the computational speed of the applied cryptographic mechanisms.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.173-182
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• 1999

Contrast-enhanced CT has an important role in assessing liver lesions, the optimal protocol to get most effective result is not clear. The mein goal when deciding injention protocol is to optimize lesion detectability with rapid scanning when lesion to liver contrast is maximum. For this purpose, we developed a physiological model of the contrast medium enhancement based on the compartment modeling and pharmacokinetics. Blood supply to liver is achieved in two paths. This dual supply characteristic distinguishes the CT enhancement of liver from that of the other organs. The first path is by hepatic artery and to second, by portal vein. However, it is assumed that only gepatic artery can supply blood to hepatocellular carcinoma(HCC) compartment, thus, the difference of contrast enhancement is resulted between normal liver tissue and hepatic tumor. By solving differential equations for each compartment simultaneously using the computer program Matlab, CT contrast-enhancement curves were simulated. The simulated enhancement curves for aortic, hepatic, portal vein, and HCC compartments were compared with the mean enhancement curves from 24 patients exposed to the same protocols as the simulation. These enhancement curves showed a good agreement. Furthermore, we simulated lesion-to-liver curves for various injection protocols, and the effects were analyzed. The variables to be considered in the injection protocol were injection rate, dose, and concentration of contrast material. These data may help to optimize scanning protocols for better diagnosis.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.15-34
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• 2006

This paper introduces an empirical modeling technique. This technique uses a set of sample results which are collected from a few small scale simulations. Empirical models are developed by applying a couple of statistical estimation techniques to these samples. We built two types of models for cache miss rates in Symmetric Multiprocessor systems. One is for the changes of input data set size while the specification of target system is fixed. The other is for the changes of the number of processors in target system while the input data set size is fixed. To develop accurate models, we built individual model for every kind of cache misses for each shared data structure in a program. The final model is then obtained by integrating them. Besides, combined use of Least Mean Squares and Robust Estimations enhances the quality of models by minimizing the distortion due to outliers. Empirical modeling technique produces extremely accurate models without analysis on sample data. In addition, since only snail scale simulations are necessary, once a set of samples can be collected, empirical method can be adopted in any research areas. In 17 cases among 24 trials, empirical models present extremely low prediction errors below $1\%$. In the remaining cases, the accuracy is excellent, as well. The models sustain high quality even when the behavioral characteristics of programs are irregular and the number of samples are barely enough.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.107-130
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• 2010

The purpose of this study is to investigate the characteristics that indicate scientifically gifted students by analyzing the verbal interactions in developmental biology inquiry-experimental classes. The subjects were 20 first-grade middle school students who were participating in SNU Science Gifted Education Center. In these experimental classes which were developed based on the CPS Model, we conducted a total of four experimental sessions of small group discussions, and the students' verbal interactions were both taped and video recorded, and observed. From the transcriptions, the patterns of question-answer and the characteristics of scientifically gifted students were analyzed. In the case of question-answer patterns, thinking questions appeared 3~6 times more frequently than the standard information questions. Especially, the case of experimental class I showed 40% more thinking questions as well as standard information questions that the other 3 classes. Through the results of analysing verbal interactions, we were able to find more detailed aspects to creativity that were not identifiable in paper-pencil examinations, as well as affective characteristics such as task commitment and leadership. We believe our findings upon inquiry will be of substantial significance in substituting for the paper-pencil examination in distinguishing and selecting scientifically gifted students.