• Journal of the Korean earth science society
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• v.32 no.3
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• pp.249-264
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• 2011

A multi-Gaussian kriging approach extended to space-time domain is presented for uncertainty modeling as well as time-series mapping of environmental variables. Within a multi-Gaussian framework, normal score transformed environmental variables are first decomposed into deterministic trend and stochastic residual components. After local temporal trend models are constructed, the parameters of the models are estimated and interpolated in space. Space-time correlation structures of stationary residual components are quantified using a product-sum space-time variogram model. The ccdf is modeled at all grid locations using this space-time variogram model and space-time kriging. Finally, e-type estimates and conditional variances are computed from the ccdf models for spatial mapping and uncertainty analysis, respectively. The proposed approach is illustrated through a case of time-series Particulate Matter 10 ($PM_{10}$) concentration mapping in Incheon Metropolitan city using monthly $PM_{10}$ concentrations at 13 stations for 3 years. It is shown that the proposed approach would generate reliable time-series $PM_{10}$ concentration maps with less mean bias and better prediction capability, compared to conventional spatial-only ordinary kriging. It is also demonstrated that the conditional variances and the probability exceeding a certain thresholding value would be useful information sources for interpretation.

• Current Research on Agriculture and Life Sciences
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• v.31 no.3
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• pp.200-208
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• 2013

The purposes of this study are developing a stress index for each individual major trail in the national parks and contribute to establishing a park management policy based on scientific analyses using the index. We collected data from 144 sections of trails in national parks, conducted the Delphi survey and factor analysis, and generated the stress index by standardizing scores of factors contributing to the stress for each trail. As aresult, total eight factors contributing to the stress were considered and four of them, i.e. the amount of visits, the effect of visits, the degree of trail destruction, and species diversity, were selected to generate the stress index. How to weigh factors was determined by their importance obtained in the second Delphi survey and the average from a 5 point Likert scale. Then, the cumulative probabilities from the standardized scores were graded into five groups. In conclusion, there were twenty trails from the six national parks including Jirisan, Bukhansan, Deogyusan, Naejangsan, Seoraksan in the first grade which gained over 80 as the stress index.

• Phonetics and Speech Sciences
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• v.14 no.3
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• pp.41-49
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• 2022

The average acoustic distribution of American English speakers was statistically compared with the English-speaking patterns of gifted students in a Science Academy in Korea. By analyzing speech recordings, the duration time of which is much longer than in previous studies, this research identified the degree of acoustic proximity between the two parties and the predictability of English academic achievement of gifted high school students. Long-term spectral acoustic power distribution vectors were obtained for 2,048 center frequencies in the range of 20 Hz to 20,000 Hz by applying an long-term average speech spectrum (LTASS) MATLAB code. Three more variables were statistically compared to discover additional indices that can predict future English academic achievement: the receptive vocabulary size test, the cumulative vocabulary scores of English formative assessment, and the English Speaking Proficiency Test scores. Linear regression and correlational analyses between the four variables showed that the receptive vocabulary size test and the low-frequency vocabulary formative assessments which require both lexical and domain-specific science background knowledge are relatively more significant variables than a basic suprasegmental level English fluency in the predictability of gifted students' academic achievement.

• Journal of the Korean Regional Science Association
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• v.40 no.3
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• pp.75-93
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• 2024

This study examines the impact of moving to an opportunity-rich area on an individual's wage income to identify the relationship between regional disparities in opportunities throughout a person's life cycle and life outcomes. Based on the Graduate Occupational Mobility Survey (GOMS) provided by the Korea Employment Information Service, individuals with similar life experience prior to regional mobility were selected and analyzed using the Propensity Score Matching (PSM) method. Specifically, the life cycle was classified into stages such as pre-high school, university entrance period, and employment period. Then, a path model was established to analyze regional mobility, education, employment, and wage income by life cycle stage. The analysis results indicate that the life cycle stage where regional mobility had the greatest impact on an individual's economic performance, that is, the stage where the impact of opportunity disparities was most unequal, was the university entrance period. Additionally, moving to an opportunity-rich area was a critical factor that cumulatively affected subsequent life. Hence, pre-high school mobility was also noteworthy as it induced life in the central area later on. Lastly, while parental income itself was influential, but when combined with regional mobility, it could act as a means of transferring wealth to the next generation. These results suggest that the state should strive to alleviate the regional imbalance around universities by fostering universities outside the capital region and reduce the possibility of the influence of parents' socio-economic background on regional mobility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.942-952
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• 2008

The purpose of this research was to evaluate the quality of take-out services at restaurants in Chungbuk Province. A questionnaire survey by 450 customers who had experience in take-out service at the restaurants was conducted and 378 completed questionnaires were available for statistical evaluation. Statistical analyses were made of raw data by SAS V8.2. The scale for analyzing the importance and performance of the service quality was composed of 5-point Likert scales. The main results of this study are as follow: The quality attributes of take-out service were rearranged into four factors in terms of food, sanitation, access and service. The importance score was higher than performance score. IPA showed that 'freshness of food material', 'cleanliness and hygiene in food', 'sanitation of facilities', 'neatness of employees' and 'price in food' was included in 'focus here' area. There was significantly positive correlation between factors such as food, sanitation, access, service and overall customer satisfaction (p<.001); between factors and repurchasing intentions (p<.001); and between customer satisfaction and repurchasing intentions (p<.001). According to multiple regression analysis, 26.27% of the variance in respondents' overall satisfaction score and 9.21% of the variance in respondents' repurchasing intention score could be explained by factors such as food, sanitation, access and service.

• The KIPS Transactions:PartA
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• v.9A no.3
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• pp.301-310
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• 2002

Internet has been applied to the educational field such as data search, lecture by motion picture, realtime examination. Most questions made for these remote examinations use methods of making questions randomly using fixed questions or item pools. The designed system in this paper makes questions without knowing MARK-UP language and after undergoing examinations on Web. Also it readjusts degree of difficulty automatically on the basis of the rate of correct answers. In addition, this enables learners to perform feedback learning after examinations and subsequently learners themselves to adjust their degree of difficulty and undergo reexaminations. The automatic selection system makes it easy to select questions, possible to expect average marks and number of questions made, and to prevent that questions may be made too easy or too hard. For a remote examination, as there are much possibilities of dishonesty such as examination by proxy so different types of problems are made, and problems of the rationality caused from that can be avoided.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.101-114
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• 2008

Ubiquitous City (u-City) and Intelligent Transport System (ITS) provide services, which are different from each other yet have close relation to each other partially. Thus, since a redundancy issue occurs or it is difficult to efficiently provide services depending on the relation degree, it is required to analyze the relation of services between the two systems and to elicit a priority. A table of relation among the services was created and the relation degree was analyzed by performing a survey for experts. As a result of calculating the total marks by accumulating and summing up the survey results, the incident management service and u-accident/calamity and disaster service of the ITS had the lowest value. The project priority was as follows: The basic principle of the project was that services with high relation degrees shall be worked on first. The services were categorized in each step and packaging the services could result in the synergy effect. This study is significant since it analyzed the relation degree between u-City and ITS and proposed schemes for efficiently working on the project by eliciting the priority of the services based on the analysis results.

• The KIPS Transactions:PartB
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• v.10B no.1
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• pp.119-126
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• 2003

This study suggests the configuration of network game portal site supporting multi-platform that indicates different types of games so called Game Omphalos or simply Gamphalos. In general, the existing game Portal site only put the different games together and operates each game separately. But, not only the Gamphalos system can play the various games in a portal site but also integrates the data of different games for inter-working among them. To do this, the Gamphalos System consists of two main parts. The one is Global Game Control Center (GGCC) for integrated management of n and game data. And the other part it Local Game Control Center (LGCC) that serves as a game server for each game. The game user who becomes a member of the Gamphalos System can get more Points and grow rapidly than others because all the game data can be integrated and accumulated in a Gamphalos system.

• Journal of Industrial Convergence
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• v.21 no.3
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• pp.37-48
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• 2023

Universities in Korea are presenting various extracurricular activities for survival and growth. Although the goals of extracurricular activities are diverse, one of the most important is to improve the academic achievement of college students. In this study, we looked at the relationship between the cumulative score of extracurricular activities by difficulty level and academic achievement. As a result, first, even if students' basic academic skills were controlled, extracurricular activities had a positive effect on student achievement. This suggests that universities should provide extracurricular activities that are more diverse and tailored to the needs of students. Second, the participation rate of female students in extracurricular activities is similar to that of male students, but the performance is very high. Third, Senior students show high levels of participation and performance. This means that it is necessary to actively increase the participation rate of female students and lower grade students. To this end, not only publicity and compensation, but also active interest and participation of instructors will be required.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.34-41
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• 2021

Purpose: To evaluate the long-term clinical results and survivorship of unicompartmental knee arthroplasty (UKA) in elderly patients older than 70 years by analyzing cases that have been implanted for >10 years ago. Materials and Methods: The long-term follow-up results were evaluated in 39 patients (46 cases) who underwent medial UKA from March 2002 to February 2004. The mean age of the patients at the time of surgery was 74.0 years, and the preoperative diagnosis was degenerative arthritis of the knee in all cases. Results: Of the 46 cases, reoperation occurred due to the complications in four cases. In 22 cases without 14 cases of death and six cases of follow-up loss, follow-up more than 10 years was possible. The mean Knee Society knee and function scores improved significantly from 53.0 and 52.5 points pre-operatively to 89.4 and 80.9 points at the last follow-up, respectively (p<0.001). The mean range of motion of the knee recovered to 132.5°, and the mean tibiofemoral angle changed to 5.9° of valgus at the last follow-up. Complications following the UKA occurred in four cases; the most prevalent complication was mobile bearing dislocation (n=2). One case of failure occurred due to aseptic loosening and degenerative arthritis of the lateral compartment, respectively. The cumulative survival rate of the implants was 95.0% at 10 years and 85.7% at 15 years. Of the 40 cases, excluding six cases of follow-up loss, 36 cases (90.0%) could be used without reoperation until death or at the last follow-up after surgery. Conclusion: These results showed the outstanding functions of the knee and satisfactory long-term survivorship after UKA. Therefore, UKA could be a useful method for the treatment of osteoarthritis of the knee in elderly patients older than 70 years of age.