• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.125-131
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• 2007

Biodegradable polymeric blends are expected to be widely used by industry due to their environmental friendliness and comparable mechanical and thermal properties. Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) are such biodegradable polymers which aim to replace commodity polymers in future applications. Since cost and brittleness of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. In this study, blends of PLA and PBS with various compositions were prepared by using a laboratory-scale twin-screw extruder at $180^{\circ}C$. Morphological, thermal, rheological and mechanical properties were investigated on the samples obtained by compression molding to explore suitability of these compositions for packaging applications. Morphology of the blends was investigated by scanning electron microscopy (SEM). Morphology showed a clear phase difference trend depending on blend composition. Modulated differential scanning calorimetry (MDSC) thermograms of the blends indicated that the glass transition temperature ($T_g$) of PLA did not change much with the addition of PBS, but analysis showed that for PLA/PBS blend of up to 80/20 composition there is partial miscibility between the two polymers. The tensile strength and modulus were measured by the Instron Universal Testing Machine. Tensile strength, modulus and percentage (%) elongation at break of the blends decreased with PBS content. However, tensile strength and modulus values of PLA/PBS blend for up to 80/20 composition nearly follow the mixing rule. Rheological results also show miscibility between the two polymers for PBS composition less than 20% by weight. PBS reduced the brittleness of PLA, thus making it a contender to replace plastics for packaging applications. This work found a partial miscibility between PBS and PLA by investigating thermal, mechanical and morphological properties.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.2
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• pp.65-76
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• 2009

This study was to examine of physical and psychological traits to sasang constitution in college students. The subjects in this study were 114 people, who were consists of 35 persons of Taeeumin, 34 persons of Soyangin and 45 persons of Soeumin. We were analyzed psychological trait with the Myers-Briggs Type Indicators(MBTI) and State-Trait Anxiety Inventory(STAI) according to sasang constitution. Also, We were analyzed physical trait with the Body Mass Index(BMI) according to sasang constitution. Each sasang constitutions personality type showed significantly differences only in the extraversion and introversion(p=0.012). In the relationship of BMI, Taeeumin showed bigger BMI compared to others (p<0.001). As a result of logistic regression analysis, Soyangin was higher in the extraversion(odds ratio[OR], 3.48 ; 95% confidence interval [95% CI], 1.18-10.26) compared with Taeeumin. Also, each sasang constitutions showed significantly differences in trait-anxiety(p=0.047). The score of trait-anxiety in Soeumin was significantly higher than that in Taeeumin. The limitation of this study was that particular samples could not represent the population, because the students from one college had participated in this study. In the future, we will perform this study in general population. At the same time, we will also develop approaches considering physical and psychological aspects depending on the types of constitution in the management of subjects.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.578-587
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• 2019

The purpose of this study is to examine differences in mental health indices such as self-compassion, trait anxiety, and depression, and color preference based on Sasang Constitution type. This study also explored the relationships among self-compassion, trait anxiety, and depression. 205 adults were surveyed for participants of this study. A Two-Step Questionnaire (TS-QSCD) was conducted to diagnose Sasang Constitution such as Tae-yangin, Tae-yinin, So-yangin, and So-yinin. Also, scales for self-compassion, trait anxiety, depression level, and color preference were utilized for measures. The results showed that among Sasang Constitutional groups, Ta-yangin had a higher level of self-compassion and lower trait anxiety than So-yinin. Furthermore, in relationships among mental health indices, trait anxiety and depression tendency were lower with higher self-compassion. No significant differences were revealed in depression level and color preference based on Sasang constitution. Finally, implications of this study for mental health were suggested and limitations were discussed.

• The Journal of Information Systems
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• v.30 no.4
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• pp.21-42
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• 2021

Purpose In order for companies to continue to grow, they should properly manage human resources, which are the core of corporate competitiveness. Employee turnover means the loss of talent in the workforce. When an employee voluntarily leaves his or her company, it will lose hiring and training cost and lead to the withdrawal of key personnel and new costs to train a new employee. From an employee's viewpoint, moving to another company is also risky because it can be time consuming and costly. Therefore, in order to reduce the social and economic costs caused by employee turnover, it is necessary to accurately predict employee turnover intention, identify the factors affecting employee turnover, and manage them appropriately in the company. Design/methodology/approach Prior studies have mainly used logistic regression and decision trees, which have explanatory power but poor predictive accuracy. In order to develop a more accurate prediction model, XGBoost is proposed as the classification technique. Then, to compensate for the lack of explainability, SHAP, one of the XAI techniques, is applied. As a result, the prediction accuracy of the proposed model is improved compared to the conventional methods such as LOGIT and Decision Trees. By applying SHAP to the proposed model, the factors affecting the overall employee turnover intention as well as a specific sample's turnover intention are identified. Findings Experimental results show that the prediction accuracy of XGBoost is superior to that of logistic regression and decision trees. Using SHAP, we find that jobseeking, annuity, eng_test, comm_temp, seti_dev, seti_money, equl_ablt, and sati_safe significantly affect overall employee turnover intention. In addition, it is confirmed that the factors affecting an individual's turnover intention are more diverse. Our research findings imply that companies should adopt a personalized approach for each employee in order to effectively prevent his or her turnover.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.52-76
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• 2000

Following the previous study focused on the period until the middle of the 20th century, this study tried to show how STS-related ideas have been developed historically in British science education, particularly focused on the period of the 2nd half of the 20th century. Like the USA, the UK witnessed the development of numerous academically-oriented programs, such as Nuffield projects, during the 1950-60s. However, during the 1970s, there had been growing criticism against the discipline-centered science education and some new noticeable approaches had been made to compensate the contemporary trend. For example, although its main focus was on the integrated approach in school science, the SCISP was quite successful to illustrate the importance of the relationship between science and society. Following this example, Science in Society and SISCON-in-Schools were more ambitious in developing genuine STS programs. These two projects were developed simultaneously and took the form of modules, rather than of textbooks. Nevertheless, Science in Society was more concerned with the applied and industrial aspects of science while SISCON-in-Schools was more inclined to the historical, philosophical and social aspects of science. During the 1980s, far more ambitious attempts had been made to develop full-scale STS programs, i.e. Salters' Chemistry/Science and SATIS. These two programs have been developed with the active corporation from the ASE and soon became the typical examples of the STS approach across the world. Besides the similarities between them, Salters' approach is more application-oriented, subject-oriented, and textbook-like while SATIS is more socially-oriented, issue-oriented and module-style. In summary, the history of STS approach in school science shows that the STS programs were developed under the different social backgrounds and initiated by different groups of the people who have different views towards the purposes of school science and that the STS approach is certainly not the exclusive characteristic of the last period of the 20th century. Finally, the features of the major STS programs developed in Britain during the 20th century are summarized and compared in relation to the Ziman's criteria of the possible approaches in STS education. And some general conclusion are drown based on the study of the history of the STS approaches in Britain.

• Management & Information Systems Review
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• v.33 no.2
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• pp.301-315
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• 2014

The purpose of this study is to estimate the economic value of the Kumjung Mountain, using a Individual Travel Cost Model(ITCM). This paper compares Poisson and negative binomial count data models to measure the tourism demands. Interviewers were instructed to interview only individuals. So the sample was taken in 700. A dependent variable that is defined on the non-negative integers and subject to sampling truncation is the result of a truncated count data process. The results suggest that the truncated negative binomial model is improved overdispersion problem and more preferred than the other models in the study. This study emphasizes in particular 'travel cost' that is not only monetary cost but also including opportunity cost of 'travel time'. According to the truncated negative binomial model, estimates the Consumer Surplus(CS) values per trip of about 60,669 Korean won and the total economic value was estimated to be 252,383 Korean won.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.90-96
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• 2002

The STS contents, emphasized in the 6th curriculum, in the chemistry textbooks(II) were analyzed. The STS contents in textbooks showed average value of 2.7%. The chapter of ‘chemical bond and compound' were included 3.8% of STS contents. And the chapter of ‘atomic structure and periodic table', ‘state of material and solution', ‘science of material', and ‘chemical reaction' contained 3.2%, 2.2%, 1.9%, and 1.9% of STS contents, respectively. When the STS contents were analyzed by STS topics of Piel, the results are as follows; 33.7% on effect of technological developments, 27.5% on environmental quality and utilization of natural source, 19.6% on human engineering, 13.8% on energy, and 5.4% on sociality of science. However, there were no topics on population, space research and national defense. When the STS contents were analyzed by student activities of SATIS, most of the activities were research and case study. There were few field activities of practical investigation, problem solving and decision making, research design and stimulation. There were no activities of role play.

• Journal of The Korean Association of Information Education
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• v.1 no.1
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• pp.82-91
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• 1997

The purpose of thesis is to design and implement an efficient Internet-Based courseware which facilitates the problem solving learning. This courseware was developed in order to provide important foundations of learning in open-education environment using WWW. The targeted level is elementary students, To do this, the definition of problem solving, its processes, and advantages or pitfalls of computer-based problem solving learning were examined, with the advantage of using WWW as an educational tool. The theme of implemented courseware was selected from SATIS which is relevant for the problem solving learning. The courseware has three main parts; learning activity module, teaching activity module, and learning tool module. The learning activity module controls courseware flows and was implemented in accordance with the problem-based teaming processes. It: can be proceeded either sequential way or random access by setting linker. The advantage of random accessing method is that it may facilitate student learning because each student can regulate their learning processes which correspond to their own experiences. The teaching activity module provides for teachers useful informations for helping student's learning and it also can be used as an assessment tool for student's achievements, The learning: tool module consists of conversational note, e-mail address, help, and search tool. It is linked with learning activity module and teaching activity module so that teachers and students can actively participate in teaching-learning processes.

• Journal of Sasang Constitutional Medicine
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• v.12 no.1
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• pp.136-143
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• 2000

1. Purpose of study : In Oriental Traditional medicine, especially in Sasang Constitutional Medicine the mind and the body are not separated. Psychological characteristics are very important as well as physical characteristics in Sasang Constitutional Medicine. This study was performed to investigate the psychological characteristics of Sasang Constitution. 2. Subjects and Methode of Study : Subjects were 63 persons. There were male 54 and female 9 who were healthy. There were Taeumin 35, Soumin 17, and Soyangin 11. We judged Sasang Constitution in QSCC II and the diagnosis by a medical specialist. The degree of depression and anxiety was determined by Beck's Depression Inventory(BDI) and State-Trait Axiety Inventroy(STAI, State Anxiety : S-A, Trait Anxiety : T-A). We studied the psychological characteristics - Depression and Anxiety - in the Sasang Constitution by analyzing BDI and STAI scores. 3. Result of study : 1) The score of STAI(S-A) in Soeumin(少陰人) group was significantly higher than that in Taeumin(太陰人) group. 2) The score of STAI(T-A) in Soeumin(少陰人) group was significantly higher than that in Taeumin(太陰人) group and Soyangin(少陽人) group. 3) The score of BDI in Soeumin(少陰人) group was higher than that in Taeumin(太陰人) group and Soyangin(少陽人) group, but it was not significant statistically. 4. Conclusion of study These result suggest that Soeumin(少陰人) is more anxious than Soyangin(少陽人) and Taeumin(太陰人).

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.256-263
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• 2001

The STS contents, emphasized in the 6th curriculum, in the chemistry parts of general science textbooks were analyzed. The STS contents of textbooks showed average of 24.4%. The chapter in "modern science and technology" were included 45.5% in STS contents, 38.7% in "environment", 29.1% in energy, and 14.0% in "materials". When the STS contents were analyzed by STS topics of Piel, the results are as follows; 38.3% on environmental quality and utilization of natural source, 29.6% on effect of technological developments, 7.9% on energy, and 0.6% on human engineering. However, there were no topics on population, space research and national defense. When the STS contents were analyzed by student activities of SATIS, most of the activities were research and case study. There were few field activities of role play, problem solving and decision making, and research design.