• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.159-163
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• 2005

The propriety between suppliers and demanders in geometric design is very important. Although the final purpose of constructing roads is to concern about the driver s comfort, unfortunately, it has not been considered so far. We've considered the regularity and quickness in considering driver's comfort but there should be considered the safety for the accident as well. If drivers are appeared to be more speeding than designer's intention, there will be needed some supplements to increase the safety rate for the roads. Even if both an upward and downward section are supposed to exist at the same time for solid geometry of the roads like this, it is true that the recent design for the 3-D solid geometry section has been done as flat 2-D and the minimum plane curve radius and the maximum cant have been decided just by calculating without considering operating speed between an upward and downward section at the same point. In this investigation, thus, I'd like to calculate the safety of the cant by considering the speed features of the solid geometry for the first lane of four lane rural roads. To begin with, we investigated the driving speed of the car, which is not been influenced by a preceding car to analyze the influence of the geometrical structure by using Nc-97. Secondly, we statistically analyzed the driving features of the solid geometry after comparing the 6 sections, that is, measuring the driving speed feature at 12 points and combining the influence of the vertical geometry and plane geometry to the driving speed of the plane curve which was researched before. Finally, we estimated the value of cant which considers the driving speed not by using it which has applied uniformly without considering it properly, though there were some differences between a designed speed and driving speed through the result of the basic statistical analysis but by introducing the new safety rate rule, a notion of ${\alpha}$. As a result of the research, we could see the driving features of the car and suggest the safety rate which considers these. For considering the maximum cant, if we apply the safety rate, the result of this experiment, which considers 3-D solid geometry, there'll be the improvement of the driver's safety for designing roads. In addition, after collecting and analyzing the data for the road sections which have various geometrical structures by expanding this experiment it is considered that there should be developed the models which considers 3-D solid geometry.

• Journal of The Korean Association For Science Education
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• v.19 no.2
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• pp.185-193
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• 1999

The long term trend of studensts' science achievement is a very important factor to check the effectiveness of science educational policy. However, up to date no such effort to understand the trend of Korean students' science achievement has been put into action. Recently, the Science Education Center in Korea National University of Education has been attempted to collect nation wide data for students' science achievement. The first part of the effort was to develop item pools. This study was the second part to collect nation wide data and to check any change during the two year time interval. In this study, the item pools developed by Kwon et. al.(1998) were used with some modification. The data were collected two times; February 1997 and March 1999. The subjects collected nationally were 8,766 students in 1997 and were 4,398 in 1999. The subjects were collected randomly but stratified by region and sex. As the results, the trends of achievement change during the two years were different from elementary to high school. The achievement scores were decreased in elementary schools and increased in high school. In case of middle schools, the change was not significant. However, even in elementary schools the knowledge on theory was increased significantly while knowledge on facts and principles were decreased. In contrast, the knowledge on fact showed the most increase in high schools. In this study, the data were analysed in light of region, sex, behavioral objective levels(ability) and context of test items. The science achievement monitoring system developed by the Science Education Center in Korea National University of Education can be an effective tool for monitoring students' achievement on the national level.

• Journal of Intelligence and Information Systems
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• v.23 no.1
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• pp.1-22
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• 2017

Analysis of future business or investment opportunities, such as business feasibility analysis and company or technology valuation, necessitate objective estimation on the relevant market and expected sales. While there are various ways to classify the estimation methods of these new sales or market size, they can be broadly divided into top-down and bottom-up approaches by benchmark references. Both methods, however, require a lot of resources and time. Therefore, we propose a data-based intelligent demand forecasting system to support evaluation of new business. This study focuses on analogical forecasting, one of the traditional quantitative forecasting methods, to develop sales forecasting intelligence systems for new businesses. Instead of simply estimating sales for a few years, we hereby propose a method of estimating the sales of new businesses by using the initial sales and the sales growth rate of similar companies. To demonstrate the appropriateness of this method, it is examined whether the sales performance of recently established companies in the same industry category in Korea can be utilized as a reference variable for the analogical forecasting. In this study, we examined whether the phenomenon of "mean reversion" was observed in the sales of start-up companies in order to identify errors in estimating sales of new businesses based on industry sales growth rate and whether the differences in business environment resulting from the different timing of business launch affects growth rate. We also conducted analyses of variance (ANOVA) and latent growth model (LGM) to identify differences in sales growth rates by industry category. Based on the results, we proposed industry-specific range and linear forecasting models. This study analyzed the sales of only 150,000 start-up companies in Korea in the last 10 years, and identified that the average growth rate of start-ups in Korea is higher than the industry average in the first few years, but it shortly shows the phenomenon of mean-reversion. In addition, although the start-up founding juncture affects the sales growth rate, it is not high significantly and the sales growth rate can be different according to the industry classification. Utilizing both this phenomenon and the performance of start-up companies in relevant industries, we have proposed two models of new business sales based on the sales growth rate. The method proposed in this study makes it possible to objectively and quickly estimate the sales of new business by industry, and it is expected to provide reference information to judge whether sales estimated by other methods (top-down/bottom-up approach) pass the bounds from ordinary cases in relevant industry. In particular, the results of this study can be practically used as useful reference information for business feasibility analysis or technical valuation for entering new business. When using the existing top-down method, it can be used to set the range of market size or market share. As well, when using the bottom-up method, the estimation period may be set in accordance of the mean reverting period information for the growth rate. The two models proposed in this study will enable rapid and objective sales estimation of new businesses, and are expected to improve the efficiency of business feasibility analysis and technology valuation process by developing intelligent information system. In academic perspectives, it is a very important discovery that the phenomenon of 'mean reversion' is found among start-up companies out of general small-and-medium enterprises (SMEs) as well as stable companies such as listed companies. In particular, there exists the significance of this study in that over the large-scale data the mean reverting phenomenon of the start-up firms' sales growth rate is different from that of the listed companies, and that there is a difference in each industry. If a linear model, which is useful for estimating the sales of a specific company, is highly likely to be utilized in practical aspects, it can be explained that the range model, which can be used for the estimation method of the sales of the unspecified firms, is highly likely to be used in political aspects. It implies that when analyzing the business activities and performance of a specific industry group or enterprise group there is political usability in that the range model enables to provide references and compare them by data based start-up sales forecasting system.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.3
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• pp.31-42
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• 2013

This study was carried out to systematically maintain and manage the trails by assessing the types of deterioration and naturalness of trails located in Mt. Toham, Mt. Nam, Mt. Danseok and in the Mt. Gumi district of the Gyeongju National Park. The route length of Mt. Toham was 2.7km, 2.3km of Mt. Nam, 1.0km of Mt. Danseok and 2.7km of Mt. Gumi district. The numbers of measuring points in Mt. Toham were 37 units, 29 units of Mt. Nam, 16 units of Mt. Danseok and 40 units of Mt. Gumi district. In characteristics of physical environments, Mt. Danseok was the widest and Mt. Gumi was the narrowest in the width of trail. In the bared width of trail, Mt. Danseok was the widest and Mt. Gumi was the narrowest. In depth of erosion, Mt. Danseok was the deepest and Mt. Gumi was the shallowest. Mt. Danseok was the steepest and Mt. Nam was the gentlest in the longitudinal slope. In the results of analysing the types of deterioration, Mt. Toham were 10 types, 14 types of Mt. Nam, 11 types of Mt. Danseok and 9 types of Mt. Gumi district. The times of appearance of deterioration types in Mt. Toham were 69 times, 87 times of Mt. Nam, 67 times of Mt. Danseok and 71 times of Mt. Gumi district. The most common type was the exposure of root in 4 districts of Gyeongju National Park. In the results of assessing the naturalness, Mt. Toham was 2.1 score(II degree), 2.6 score(II degree) of Mt. Nam, 2.9 score(III degree) of Mt. Danseok and 2.0 score(II degree) of Mt. Gumi district. The average naturalness was 2.4 score and II degree.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.137-153
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• 2000

In this study. 'extended science investigation' was conceptualized as a comprehensive science investigation contrasted with exercise of process and skill component and cookbook style experiment. The extended investigations should be pursued for giving opportunity of more authentic science activities in school science. And one of important educational objectives in students' science investigations is to achieve motivation for investigation which drives and triggers further investigations. It can be discerned as positive and negative by its direction and also as internal and external by its cause. The purpose of this study was to describe change of students' motivation for investigation while they were performing the extended science investigations. The subject was 128 7th grader attending coeducational school in Seoul. Questionnaires and students' reports were analysed complementarily to describe students' motivation for investigation. The number of students who showed positive motivation for investigation did not increase in the developed extended investigations than in the directive investigations in textbook, but the cause of positive motivation for investigation has changed largely from task-exclusive factors to task-inclusive factors. In case of negative motivation for investigation, regardless of the kind of investigation task, task-inclusive factors were recognized as the main causes. Among those whose motivation changed during successive extended investigations, the students who showed change from negative to positive were more than the reverse. And the number of positive intrinsic motivation for investigation was increased at the second half of the extended science investigations. So it can be said that there was a desirable change of motivation for investigation at the second half the extended science investigations.

• Journal of Nutrition and Health
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• v.48 no.3
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• pp.258-268
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• 2015

Purpose: The aim of this study was to explore the relationship of ready-to-eat cereal (RTEC) consumption with nutrition and health status. Examination of health status for this project included obesity, abdominal obesity, hypertension, hypertriglyceridemia, hypercholesterolemia, low-HDL-cholesterolemia, diabetes, anemia, and metabolic syndrome. Methods: Two groups, RTEC consumers and those who did not consume RTEC, were identified using 24-hour dietary recall data from the 2012 Korea National Health and Nutrition Examination Survey (KNHANES). Nutritional intakes and risk factors of the two groups were compared using covariates-adjusted statistical procedures. Statistical analyses were performed using SAS survey procedures, and strata, cluster, and weight were considered. Subjects of analysis of nutritional intake were between the ages of 1 and 75, and those considered in the risk factor analysis were between the ages of 19 and 75. Results: Results showed that 3.8% of the Korean population was RTEC consumers. Compared to the subjects who did not intake RTEC, RTEC consumers exhibited significantly higher intakes of calcium, thiamin, riboflavin, and vitamin C. It was also discovered that the percentage of people whose intakes were less than EAR decreased with RTEC consumption. RTEC consumption showed significant association with decreased systolic blood pressure, diastolic blood pressure, serum triglyceride, and serum total cholesterol. Consequently, prevalence of hypertension among RTEC consumers was significantly lower than that among non-consumers, and the odds ratio for hypertension was 0.19 after adjusting the models for covariates. Conclusion: Results of this study clearly suggest an association of RTEC consumption with improved nutritional status and cardiometabolic risk profile in Korean adults. Conduct of additional studies will be necessary in order to determine the nature of these relationships.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.108-116
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• 2009

In this paper, we propose a Ethernet based audio distribution system with a new L1/L2 hybrid switching scheme, and evaluate its performance. The proposed scheme not only offers guaranteed low latency and jitter characteristics that are essentially required for the distribution of high-quality uncompressed audio traffic, and but also provide an efficient transmission of data traffic on the Ethernet environment. The audio distribution system with a proposed scheme consists of a master node and a number of relay nodes, and all nodes are mutually connected as a daisy-chain topology through up and downlinks. The master node generates an audio frame for each cycle of 125us, and the audio frame has 24 time slotted audio channels for carrying stereo 24 channels of 16-bit PCM sampled audio. On receiving the audio frame from its upstream node via the downlink, each intermediate node inserts its audio traffic to the reserved time slot for itself, then relays again to next node through its physical layer(L1) transmission - repeating. After reaching the end node, the audio frame is loopbacked through the uplink. On repeating through the uplink, each node makes a copy of audio slot that node has to receive, then play the audio. When the audio transmission is completed, each node works as a normal L2 switch, thus data frames are switched during the remaining period. For supporting this L1/L2 hybrid switching capability, we insert a glue logic for parsing and multiplexing audio and data frames at MII(Media Independent Interlace) between the physical and data link layers. The proposed scheme can provide a good delay performance and transmission efficiency than legacy Ethernet based audio distribution systems. For verifying the feasibility of the proposed L1/L2 hybrid switching scheme, we use OMNeT++ as a simulation tool with various parameters. From the simulation results, one can find that the proposed scheme can provides outstanding characteristics in terms of both jitter characteristic for audio traffic and transmission efficiency of data traffics.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.601-615
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• 1998

Establishing and evaluating science education policies and revising and monitoring the effectiveness of science curriculum should be based upon the results of systematic and scientific research studies. Advanced nations have already been administering and developing national level science assessments for these purposes. The science assessments administered in Korea have been reported having many limitations and problems, and not succeeded in providing data for science education policy making and curriculum reform. The major purpose of the study is developing national level science knowledge assessment system in order to identify longitudinal trends of elementary and secondary school students science knowledge achievements. The research team consisted of science education experts and teachers from various school levels, decided the directions and major elements of national level science knowledge assessment with the consultation of educational evaluation experts. Item developing ability of the researchers was improved by seminars? and workshops on national assessment in advanced nations and developing skills of writing science items. Nearly 500 items were developed and revised. Pilot test was administered with 958 students at various school levels. 380 items were selected and tested with 8766 students, and the characteristics were analyzed in terms of item response theory. The target populations for national level science knowledge assessment are 5th-grade of elementary school, 2nd-grade of middle school, 1st and 2nd-grade of high school students. The proper period for the assessment is February every year. Multi-stage clustered sampling method is desirable and rotated forms are recommendable for the test format. Bridge items should be introduced to compare the results of multiple tests, and various grades. Anchor items should also be used for longitudinal interpretations of the results. The items for elementary school require low to medium abilities, for middle school and first grade of high school require medium to high abilities and for 2nd-grade of high school high abilities. The discrimination ability of the items developed is high.

• Management & Information Systems Review
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• v.36 no.3
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• pp.131-150
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• 2017

The purpose of this study is to observe the spread pattern of open source software (OSS) while establishing relations with surrounding actors during its operation period. In order to investigate the change pattern of participants in the OSS, we use a netnography on the basis of online data, which can trace the change patterns of the OSS depending on the passage of time. For this, the cases of three OSSs (e.g. jQuery, MooTools, and YUI), which are JavaScript frameworks, were compared, and the corresponding data were collected from the open application programming interface (API) of GitHub as well as blog and web searches. This research utilizes the translation process of the actor-network theory to categorize the stages of the change patterns on the OSS translation process. In the project commencement stage, we identified the type of three different OSS-related actors and defined associated relationships among them. The period, when a master commences a project at first, is refined through the course for the maintenance of source codes with persons concerned (i.e. project growth stage). Thereafter, the period when the users have gone through the observation and learning period by being exposed to promotion activities and codes usage respectively, and becoming to active participants, is regarded as the 'leap of participants' stage. Our results emphasize the importance of promotion processes in participants' selection of the OSS for participation and confirm the crowding-out effect that the rapid speed of OSS development retarded the emergence of participants.

• Journal of Korean Home Economics Education Association
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• v.29 no.3
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• pp.15-32
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• 2017

This study investigated the effectiveness of home economics class on self-esteem and stress of middle school students. Data were collected from self-reported inventory of the middle school students in Y city of Gyeonggi province and 165 data copies were used for analyses. Data were analyzed for frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, corelation and dependent t-test using SPSS/PC 18.0 program. The results were as follows. First, the average of positive self-esteem was 2.74 and that of negative self-esteem was 1.90 on a 4 Likert scale. The range of stress level was 1.88~2.48 on a 5 Likert scale. Life satisfaction was 3.90 and helpfulness of home economics class was 3.89 on a 5 point Likert scale, which means moderately high. Second, examining differences in variables according to gender, there were statistically significant differences in stress regarding family for both pre- and post-tests. Third, helpfulness of home economics class had positive correlation with positive self-esteem and life satisfaction and had negative correlation with negative self-esteem and stress, which means that home economics class enhance life satisfaction and positive self-esteem and lessen negative self-esteem and stress of middle students. Fourth, as a result of comparison of pre and post-tests, positive self-esteem, life satisfaction, and helpfulness of home economics class increased statistically after home economics classes, while stress regarding school life decreased statistically. Even though students' growth and changes resulting from learning other subjects were not controlled, it was meaningful that effectiveness of home economics class were examined and helpful information for enhancing perception of home economics education were provided.