• Journal of Drive and Control
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• v.21 no.1
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• pp.22-30
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• 2024

Gearboxes designed for reciprocating motion operating mechanisms operate under conditions where both the load and speed undergo continuous variations. When conducting durability tests on gearboxes designed for such applications, operating the target gearbox under conditions similar to the intended usage is essential. The gearbox must be operated for the required number of cycles to validate its durability under conditions mirroring its intended usage. This study devised an accelerated test method for gearboxes, which reduces operating angles and operational strokes. The reliability of the accelerated test was verified by comparing the stresses imposed on the gears under general and acceleration conditions through multi-body dynamic simulations. The results confirmed that the maximum contact stress levels under normal and accelerated conditions were within a 0.1% error range, indicating a minimal difference in the gear damage rates. However, a difference in the maximum contact stress results between the normal and accelerated conditions was observed when inertial forces acted on the output shaft due to the operational acceleration of the gearbox. Therefore, when conducting this acceleration test, caution should be exercised to ensure that the operational load on the gearbox, which affects inertia, does not significantly deviate from the conditions observed under normal operating conditions.

• Proceedings of the KOR-KST Conference
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• 2007.05a
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• pp.691-700
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• 2007

• Journal of Korean Society of Transportation
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• v.34 no.5
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• pp.394-408
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• 2016

This study aims to study the impact of weather conditions and locational characteristics of bike stations on the usage of public bike sharing system for efficient deployment and operation of public bike systems. Linear regression analysis is used to estimate the usage of public bikes of Goyang city. The statistical analysis shows that the usage rate increases with average temperature and decreases under high wind (over 7m/s) or high temperature (over $29^{\circ}$) condition. The usage rate of public bike sharing system can be differentiated by locational characteristics of bike station such as residential area, commercial area, park, school, and metro station. The usage rate increases in park and commercial areas from 10 AM to 3 PM, while it increases in school areas from 3 PM to 5 PM. Public bikes are highly used near the metro station from 5 PM to 8 PM. The stations in parks are highly used in late night, and the usage rate in CBD area increases after the midnight.

• PNF and Movement
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• v.17 no.1
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• pp.41-46
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• 2019

Purpose: Continuous use of a smartphone increases the angle of forward bending of the user's cervical vertebrae, causing pain in the shoulders and back, including the thorax, lumbar region, and vertebrae. Although there are many studies on changes in the cervical spine due to smartphone usage, the changes in the shoulders, thoracolumbar spine, and pelvic have rarely been compared. The purpose of this study is to investigate the change in the spinal segments, shoulders, and pelvic when using a smartphone with both hands while in the standing position. Methods: This study was conducted on 35 adults in their twenties. The selection criteria for the subjects were limited to those in a similar age group, thus excluding posture differences according to age, and to those who did not have specific diseases or pain in the spinal and musculoskeletal system for 12 months prior to the study. In this study, we used a 3D spinal diagnostic imaging system (Back Mapper, Frickenhausen) to compare the changing conditions in each vertebral segment before and during smartphone usage with both hands while in the standing position. Posture differences according to smartphone usage were compared using the paired t-test for the motion of each spinal segment. Results: This study showed that the thoracic and lumbar angle increased posteriorly during smartphone usage (p<0.05). In addition, the anterior rotation angle of the shoulder bone significantly increased, but no significant difference occurred in the pelvic region. Conclusion: Based on the results of this study, smartphone usage with both hands while in the standing position showed that the spine, as a whole, forms a kyphotic curve. Therefore, we propose to present a postural guideline for correct smartphone usage, considering the change in each vertebral segment.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.48-57
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• 2010

Nowadays, public rental apartments' community facilities emphasize only their quantity aspect without considering residents' characteristics, leading their installation regulations to be based on only the number of households, which is problematic. As a result, in many cases, residents, after moving in, alter the facility usage or remodel the facilities for their use. Hereby, this study conducted focus group interviews with public rental apartments' residents as to find out space conditions of and improvement demands for the community facilities. Two public rental apartment complexes in Seoul and Gyeongi-do which were built after 2007 were selected for this study. As for the survey method, workshop panel was employed. Four people in each age class of infants, children, adolescents, adults, and seniors were formed into one group, and a total of 40 people in 10 groups were surveyed. The survey was continuously conducted from February to March in 2009. The study findings can be summarized as follows. 1) Among community facilities, there were more satisfactory outdoor facilities than satisfactory indoor facilities. Residents expressed satisfaction with the facilities linked with natural environment. The causes of unsatisfactory facilities were mostly poor management. 2) The facilities demanded by the residents included ones relevant to study, exercise, and hobbies. As public rental apartments are resided mostly by low-income families, study and hobby activities bring them cost problems. Therefore, it is needed that the apartment complexes support diverse such activities 3) As for facilities demanded for usage alteration, a residents' meeting room accounted for the most popular opinions. As it was used only once a week, its usage was very low. It should be opened to the residents and allowed to be used in various ways. 4) As for demands of changing spatial characteristics, outdoor exercise facilities accounted for the most opinions. Although they were installed in most cases, they were damaged and poorly managed, therefore being in need of improvement in operation and management. In order to maximally utilize public rental apartments' community facilities, facility planning in consideration of various age groups from residents' viewpoint and sustainable systematic management are required.

• The Journal of the Korea Contents Association
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• v.8 no.3
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• pp.182-189
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• 2008

The purpose of this study were to investigate 1) present condition of children's usage of computer game, 2) difference in extent of immersing in computer game according to grade, and 3) difference in extent of immersing in computer game according to conditions of computer game usage. A total of 239 children from 1st to 3rd grade in an elementary school in Busan were surveyed with two kinds of questionnaires about usage of and immersion in computer game. The collected data were analyzed using SPSS 12.0 program. It was revealed that the 1st graders showed higher scores on experience of computer game, frequency of computer game per week, and amount of time for each computer game than the 3rd graders. However, there were no significant differences in extent of immersing in computer game according to grade and to conditions of computer game usage. The findings of this study implies that the age of using computer game is going down rapidly. Discussions and suggestions for further study were provided.

• Journal of the Korean housing association
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• v.17 no.6
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• pp.45-53
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• 2006

The study was intended to suggest the efficient usage plan of the village community center in rural area by examining the floor plan and usage pattern of the village community center and the needs of the elderly for them. This would be helpful to the welfare of the elderly in rural areas. The subjects were 24 community centers and representatives of each village, and 96 old peoples lived in there, GyungNam. The data were collected by sketching and taking pictures of community centers, and interviewing with the representatives and old peoples. The results were as follows : 1) when the percentage of old population, the physical conditions of private houses of the elderly, and the usage pattern and needs for village community center were considered, the village community center as the welfare center for the elderly would be efficient. 2) The necessary spaces in village community center were entrance, kitchen, 2 rooms, living room, restroom, and storage. In addition to these, healthcare room or auditorium can be added according to the conditions of each village. 3) The elderly wanted the village community center as a social exchange space. Therefore, two rooms which many centers had, can be used for it, one for men and another one for women. 4) The living room can be used as the space for dining. 5) Maintenance and its fee should be considered at the stage of planning. 6) The outdoor toilets should be upgraded and the indoor restroom would be desirable.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.103-113
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• 2024

This study applies the UTAUT theory to examine the intention to use online shopping mall chatbot services and to elucidate the mediating effect of anthropomorphism in their relationship. For this purpose, a sample of students from A University in Gyeongnam was surveyed online using Google Docs from the first to the second week of May 2024, and after excluding 5 insincere respondents, 245 were used for the final analysis. The key findings are as follows. First, among the UTAUT factors for online shopping mall chatbot services, performance expectancy, effort expectancy, facilitating conditions, and social influence were found to have a significant positive impact on anthropomorphism. The relative impact appeared in the order of performance expectancy, social influence, facilitating conditions, and effort expectancy. Second, anthropomorphism in online shopping mall chatbot services had a significant positive impact on usage intention. Third, the UTAUT factors of performance expectancy, effort expectancy, facilitating conditions, and social influence had a significant positive impact on usage intention, with the relative impact appearing in the order of facilitating conditions, social influence, performance expectancy, and effort expectancy. Fourth, the mediating effect of anthropomorphism was confirmed in the relationship between UTAUT factors and usage intention for online shopping mall chatbot services. This study is limited to students from A University in Gyeongnam, which may restrict the generalizability of the results. Future research should select a broader sample considering regional and demographic diversity and use diverse data collection methods to enhance the reliability and validity of the data.

• Journal of Information Technology Applications and Management
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• v.27 no.3
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• pp.1-18
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• 2020

Recently, following the development of FinTech technology that combines finance and information and communication technology, the need and social demands for a block chain technology-based trading system have increased significantly. In this study, a research model was developed and hypothesized through literature research on the concept of block chain technology, the technology acceptance model, and the unified theory of acceptance and use of technology. The research theories were tested by collecting data through surveys and analyzing the collected data. This study conducted empirical research to identify the factors influencing the user acceptance intention and utilization behavior of the block chain technology in introducing the block chain technology. First, factors affecting the acceptance intention of the blockchain user were performance expectation, effort expectation, social impact, and blockchain transparency variables. Second, the facilitation conditions and stakeholder confidence variables were analyzed as factors that did not affect the acceptability of the blockchain users. Third, variables such as blockchain transparency, stakeholder trust and intention of acceptance are factors that affect the usage behavior of the blockchain. Fourth, it was confirmed that the acceptance intention had a very high explanatory power on usage behavior of Blockchain technology.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.3
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• pp.103-108
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• 2007

This paper presents the conceptual framework for estimating and predicting system's susceptibility to failure as function of condition parameter value which is representing the current status of performance measure using on-line performance reliability. The performance of such system depends on one parameter with a probability distribution that degrades with time gracefully. Performance reliability represents the probability that physical performance will remain satisfactory over a finite period of time or usage cycles in the future. An empirical physical performance function is constructed to incorporate explanatory variables (operating and environmental conditions) over a time or usage dimension. This function enables one to model device performance and the associated classical reliability measures simultaneously, in the performance domain and time domain. The conditional performance reliability structure developed represents a tool to predict system performance over time or usage for next usage period. By enabling such a framework, it can bring us more efficient planning and execution in system's operation control as well as maintenance to reduce costs and/or increase profits.