• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.429-440
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• 2001

To achieve a computer tutor framework with high learning effects as well as practicality, the goal of this research has been set to developing an intelligent tutor for problem-solving in mathematics domain. The maine feature of the CyberTutor, a computer tutor developed in this research, is the facilitation of a learning environment interacting in accordance with the learners differing inferential capabilities and needs. The pedagogical information, the driving force of such an interactive learning, comprises of tutoring strategies used commonly in various domains such as phvsics and mathematics, in which the main contents of learning is the comprehension and the application of principles. These tutoring strategies are those of testing learners hypotheses test, providing hints, and generating explanations. We illustrate the feasibility and the behavior of our propose framework with a sample problem-solving learning in geometry. The proposed tutorial framework is an advancement from previous works in several aspects. Firstly, it is more practical since it supports handing of a wide range of problem types, including not only proof types but also finding-unkown tpes. Secondly, it is aimed at facilitating a personal tutor environment by adapting to learners of varying capabilities. Finally, learning effects are maximized by its tutorial dialogues which are derived from real-time problem-solving inference instead of from built-in procedures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.163-172
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• 2011

The CFTA girder developed is a concrete filled steel tubular system with arched shape and external post-tensioning (PT) tendons which control the initial camber and the bending stress of the girder. In the present study the effects of the PT tendons on the dynamic behavior of the girder subjected to a moving vehicle load are numerically investigated. Various levels for the tendon quantity and the tendon forces are considered, using the existing FE model of the girder. The vehicle considered is a DB-24 truck and is modeled with two tracks-three axles. Equivalent-load pulse time histories are applied to each node to simulate the moving vehicle, depending on the time of arrival and the discretization. The vehicle speeds are varied from 40 km/hr to 100 km/hr with increment of 20 km/hr. The analysis results show that the tendon forces do not produce any influences on the dynamic responses of the girder. However the dymamic deflection of the girder increases when a smaller amount of tendons is used. The Dynamic Amplification Factors (DAF) are evaluated based on the static and dynamic responses. Much lower values of the DAF are obtained, even no tendons applied, than those provided by the design criteria of the AASHTO LRFD and the Korea Highway Standard Specification.

• Composites Research
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• v.32 no.6
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• pp.355-359
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• 2019

The high efficient water splitting system should involve the reduction of high overpotential value, which was enhanced by the electrocatalytic reaction efficiency of catalysts, during the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) reaction, respectively. Among them, transition metal-based compounds (oxides, sulfides, phosphides, and nitrides) are attracting attention as catalyst materials to replace noble metals that are currently commercially available. Herein, we synthesized optimal monodisperse Co₃[Co(CN)₆]₂ PBAs by FESEM, and confirmed crystallinity by XRD and FT-IR, and thermal behavior of PBAs via TG-DTA. Also, we synthesized monodispersed Co₃O₄ nanocubes by calcination of Co₃[Co(CN)₆]₂ PBAs, confirmed the crystallinity by XRD, and proceeded OER measurement. Finally, the synthesized Co₃O₄ nanocubes showed a low overpotential of 312 mV at a current density of 10 mA·cm^-2 with a low Tafel plot (96.6 mV·dec^-1).

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.413-426
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• 2017

The study subjects were 302 adult males and females aged more than 20 years living in the metropolitan area of South Korea. This study was conducted to obtain baseline data to establish proper development and marketing strategies by examining the effects of food-related lifestyles on the importance of diet, purchasing behavior towards diet lunch boxes, and their selected attributes such as menu, packaging, and services. With respect to food-related lifestyle, a cluster analysis was performed by using five factors such as convenience factor, health factor, safety factor, taste factor, and economy factor obtained from factor analysis to derive the economy type, the taste and economy type, the convenience type, the safety type, and the health type. As a result, the respondents regarded 'food hygiene (4.59)', 'freshness (4.47)', 'taste (4.28)', and 'nutrient balance (4.19)' as the selected attributes of diet lunch box menus. Moreover, the importance of diet lunch box menus (${\beta}=0.179$) was increased with increasing safety orientation. 'Shelf life label (4.42)' was the most important selected attribute of diet lunch boxes, followed by 'ingredient label (4.19)', 'nutrition facts label (4.16)', and 'indication of origin (4.15)'. In particular, the importance of packaging for diet lunch boxes (${\beta}=0.203$) was increased with increasing safety orientation. With respect to the selected attributes of services in purchasing diet lunch boxes, 'provision of personalized menus (4.07)' was the most important, and the importance of services for diet lunch box (${\beta}=0.160$) was increased with increasing taste and economy orientation. Based on the above results, the respondents gave importance to the selected attributes related to food safety and health such as hygiene and, freshness. In addition, they also placed emphasis on hygiene and safe factors such as shelf life, ingredients, and nutrition facts labels. Therefore, it is considered necessary to develop diet lunch boxes by taking these factors into account. Furthermore, in services for diet lunch boxes, it is considered necessary to establish a service system capable of providing consumers with specialized menu or nutrition counseling according to the food-related lifestyle for their proper health management. Particularly, because consumers place emphasis on both food hygiene and safety, and health, it is considered necessary to thoroughly manage hygiene, safety, and nutrition in menu or packaging so that it is possible to enhance customer satisfaction by considering these selected attributes in greater detail.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.43-51
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• 2014

In 3-dimensional (3D) integrated package, thermal management is one of the critical issues due to the high heat flux generated by stacked multi-functional chips in miniature packages. In this study, we used numerical simulation method to analyze the thermal behaviors, and investigated the thermal issues of 3D package using TSV (through-silicon-via) technology for mobile application. The 3D integrated package consists of up to 8 TSV memory chips and one logic chip with a interposer which has regularly embedded TSVs. Thermal performances and characteristics of glass and silicon interposers were compared. Thermal characteristics of logic and memory chips are also investigated. The effects of numbers of the stacked chip, size of the interposer and TSV via on the thermal behavior of 3D package were investigated. Numerical analysis of the junction temperature, thermal resistance, and heat flux for 3D TSV package was performed under normal operating and high performance operation conditions, respectively. Based on the simulation results, we proposed an effective integration scheme of the memory and logic chips to minimize the temperature rise of the package. The results will be useful of design optimization and provide a thermal design guideline for reliable and high performance 3D TSV package.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.57-65
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• 2005

Geotextile have been used for the past 30 years for various types of containers, such as small sandbag, 3-D fabric forms and aggregate filled gabion etc. While they are mainly used for flood and water control, they are also used against beach erosion fir shore protection. Especially, large-sized geotextile tube structures are used in various innovative coastal systems involving breakwaters. This paper presents the hydrodynamic behavior of geotextile tubes based on the results of hydraulic model tests. These tube are generally about 1.0 m to 2.0 m in diameter, thou띤 they can be sized for any application. The tubes can be used solely, or stacked to add greater height and usability. Stacked geotextile tubes will be created by adding the height necessary for some breakwaters and embankment, therefore increasing the usability of geotextile tubes. The hydraulic model test was conducted as structural condition and wave conditions. Structural condition is installation direction to the wave (perpendicular and 45$^{circ}$$), and wave condition is varied with the significant wave height ranging from 3.0 m to 6.0 m. Compared with previous test result, the stacked geotextile tube is more stable against wave attack than single tube. Also, the case of none-water depth above crest is more stable than 0.5H of water depth above crest. The incline installed stacked tube is more effective for wave adsorption.

• Information Systems Review
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• v.12 no.2
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• pp.47-74
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• 2010

This study presents two dimensional views of IT-use behaviors. It examines public employee's IT-use behavior as manifested in two ways: acceptance on IT, utilization on IT. This study investigates levels of employee's the acceptance and utilization on IT in the Korean Central Government(ministry and agency) and analyses factors affecting public employee's the acceptance and utilization on task-related IT in the public sector. This study tries to examine the variables affecting the acceptance and utilization on IT; especially, the influences of such variables as leadership, task-related communication with people, task motivation, IT usability and ease of uses, task understanding in the context of Korean Central Government. Based on a questionnaire survey in Korean Central Government(8 ministries, 5 agencies) that have implemented Government Knowledge Management System(GKMS), 311 valid instruments were received and analyzed using various statistics and structural equation model(SEM). And this study will adopt try to delineate pre and intervening conditions for public employee's the acceptance and utilization. According to the results of interviews and SEM analysis suggests that the influence of task-understanding, organizational communication, IS usability were statistically significant in the acceptance and utilization on IT. And it is also hoped that the path-analytic model suggested in this study helps reveal the causal chains between the acceptance and the utilization. Especially, task-understanding proves to be important in encouraging public employee's the acceptance and utilization. This result illustrates why task-understanding people are the key to utilize the task-related IT in public organization.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.678-688
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• 2020

Occupational ethical awareness is a system of norms and standards of behavior and an important component of professionalism that affects organizational performance and commitment. The purpose of this study is to examine the mediating effect of professionalism on the relationship between job ethics and organizational commitment of civil servants. A survey was conducted on 300 central government officials with more than one year of employment. 261 copies were used for the final analysis. The results are as follows. First, the vocational ethics of civil servants had a significant effect on professionalism. The higher the years of service, the higher the level of ethics. Second, the work ethic of public officials had a significant effect on organizational commitment. These results can be interpreted as the internal commitment of civil servants to the state of work ethic. Third, the mediating effect of professionalism was verified in the relationship between public morality and organizational commitment. Based on these results, the public ethics of public servants are the basis for accepting public values and goals. Vocational expertise with embedded codes of conduct and value systems influences organizational commitment. As a practical implication for improving the ethical ethics of public officials, education programs for improving ethical consciousness according to job titles and duties were provided, and the ethical ethical competence was presented.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.197-208
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• 2015

This study is to suggest a system to increase workers' job satisfaction by analyzing the impact of conflicts in their families and work places to the satisfaction of work and the effects of personality types affecting job satisfaction. For this study, a questionnaire targeting 450 workers was conducted. As a result of this study, firstly, it was revealed that both conflicts of the family-work place and the work place-family have statistically negative interrelationships and impacts with/on job satisfaction. In terms of sub-fact categories, it is revealed that work itself has more impacts than personal persuasion based on people's value. Secondly, the results of this study concerning the conflicts in a family and the workplace shows the same result with the previous studies. They are formed by mutual interactions of cause and effect. Thirdly, it turned out that differences in Enneagram Personality Types have statistically significant impacts on job satisfaction. The result also shows that thinking-centered personalities and behavior-centered personalities have more impacts on job satisfaction than emotion-centered personalities. Study result indicates that more wide use of a psychology consultation program for workers and their families, EPA(Employee Assistant Program). It also shows that introductions of personality trainning programs and personality coaching programs are required.

• Resources Recycling
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• v.27 no.3
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• pp.8-15
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• 2018

Solvent extraction behavior of light rare earth elements (Pr, Nd) and medium rare erath elements (Tb, Dy) in the HCl-PC88A-kerosene extraction system was investigated in order to separate high-purity light rare earths (Pr, Nd) and medium rare earths (Tb, Dy) in the mixed rare earth chloride solution. In the batch test step, it was confirmed that the separation efficiency was good when the extractant concentration (PC88A) was 0.5 M, the equilibrium pH after extraction was 0.8 to 1.0 (initial pH 1.3 of the feed), the concentrations of hydrochloric acid in scrubbing solution was set as 0.1 M, the concentrations of hydrochloric acid in stripping solution was set as 2.0 M or more. Based on the experimental data obtained from the batch test, the mixer-settler was composed as follows; 4 stages of extraction, 8 stages of scrubbing, 4 stages of stripping, and 3 stages of pickling organic solution. The Mixer-settler was operated for 180 hours, and the operating conditions were continuously adjusted to obtain the high-purity light/medium rare earths. Finally, the purity of light (Pr, Nd) and medium rare earth elements (Tb, Dy) was reached as 3 N class.