• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.106-118
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• 2024

Interest in personal mobility has increased with the growing significance of first-mile and last-mile connectivity in smart mobility services. This study aims to propose a methodology for setting the service area of free-floating personal mobility sharing services and determining the optimal fleet size for the selected shared service area to address first-mile and last-mile challenges. We utilize population data, smart card data, and building data. Additionally, we estimate latent demand by incorporating age-specific and distance-specific utilization rates based on personal mobility device data. Along with the latent demand, we determine the service area based on locations of transit stops and buildings. We apply the proposed methodology to Yeongjong Island, Incheon. As a result, dense residential areas and popular beachside locations are designated as personal mobility sharing service areas. The fleet size for personal mobility in the dense residential service area is determined to be 1,022 units, while the fleet size for the beachside service area is set at 269 units.

• Journal of the Korean housing association
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• v.21 no.4
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• pp.51-58
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• 2010

In the modernization process of the city, urbanization raised a variety of social issues. Urbanization brought noticeable changes in dwelling patterns, such as drastic changes in the housing lifestyle, that revolved around the metropolitan areas of Seoul and Busan etc. before and after the expansion of economic growth. Especially in 1985, when 23.8% of the country's population was concentrated in Seoul, the imbalance of housing supply and demand caused a vast range of housing shortage. The shortage, that resulted from public sector mishandling of natural housing demand, lead to the occurrence of private sector rental housing. The occurrence of this abnormal rental housing supply, became a major cause of Korea's typical lease system called 'Co-dwelling', where the leaseholder and tenant physically lives in the same residence. The leaseholder and tenant's 'Co-dwelling' started from partial renting of traditional Korean-style housing and transformed with the transition of dwelling form and time. However, after 1985, legalization of multi-family housing, Korean rental housing started to be planned in the beginning of it's housing construction and to be produced as an independent space with separate circulation. Also in terms of facility, it changed from partial renting of a space within the residence to an assembly of small individual spaces. However, the background of this deep-rooted 'Co-dwelling' lease system, in different forms and periods of residence, is still based on the lack of public sector rental housing supply and private sector supply of rental space to utilize extra space, 'Jeonsei' payment.

• Human Ecology Research
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• v.59 no.2
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• pp.185-197
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• 2021

This study examined the impact of job demand and organizational culture on new task difficulties, burnout, and job satisfaction using a survey data of 145 family specialists in Healthy Family and Multicultural Family Support during the COVID-19 pandemic. We used the job demand-resources model and the competing values model to categorize the four dimensions of organizational culture as a conceptual framework for this study. We found that the mean of work overload was higher than the means of job conflict and job ambiguity. Our latent profile analysis proposed four profiles of organizational culture: cultural absence type, authoritative culture type, middle cultural balance type, and high cultural balance type. The results of multiple regression analyses showed that work overload was positively associated with difficulties in new task performance and burnout, job ambiguity was positively related to burnout, and job conflict and ambiguity were negatively related to job satisfaction. These findings imply that the higher the job demands reported by family specialists, the higher the level of burnout and the lower the job satisfaction. In addition, organizational culture was a unique predictor of burnout and lower level of job satisfaction. Family specialists in the groups with a high cultural balance were Family specialists in the groups with a high cultural balance were more likely to have lower levels of burnout than those in the culture absence and in the middle culture balance, and higher job satisfaction than the other groups. The results suggest that management strategies to build a creative workplace culture can prevent burnout and improve job satisfaction.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.2
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• pp.117-124
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• 2005

This study tries to develop the models of measuring the level of product availability accommodated for features of specific customers dividing customers into VIP customers and general customers. Functions of costs that the models are composed of are cost of holding safety stock and cost of lost opportunities. The existing model of measuring the level of product availability which focused on cost of holding safety stock for VIP customers should be reinforced by considering cost of lost opportunities caused by general customers' quitting trades with a company. This study tries to present realistic solutions for problems in making decisions related to the total inventory. This study concludes that the model of the level of product availability meeting general customers' needs is more efficient according to increasing of a latent demand of the general customers who quit trades with a company and the cost of lost opportunities.

• Journal of the Korean Society for Library and Information Science
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• v.42 no.2
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• pp.255-275
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• 2008

As small-scale libraries such as Children Library, Small Library, Miracle Library, have recently increased in number, it is required to establish the library consulting system in order to provide them with special knowledges and experiences necessary for library construction and operation. The result of the survey about public librarian's opinions confirms that the latent demand for library consulting is very high. In case of our country where the social experience in library consulting service is insufficient, it is desirable that the library consulting service be executed by the government offices as public service.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.613-620
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• 2017

The power grid has been changed to a smart grid system to satisfy the growing need for power grid complexity, demand, reliability, security, and efficiency with a combination of existing power and ICT technology. This study analyzes the research trends in smart grid technology in the period since the introduction of the smart grid system and compares it with industrial trends to grasp the progress and characteristics of Smart Grid technology and look for ways to innovate the technology. To do this, we analyze the research trends using dynamic topic modeling, which is capable of time-series research topic analysis. Next, we compare the results of research trends with industrial trends analyzed by Gartner's experts to demonstrate that smart grid research is evolving to the level of industrialization. The results of this study are quantitative analysis through data mining, and it is expected that it will be used in many fields such as companies that want to participate in industry and government agencies that need to establish policies by showing more objective analysis results.

• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.51-56
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• 2008

With growing demand for zero defects, predicting reliability of software systems is gaining importance. Software reliability models are used to estimate the reliability or the number of latent defects in a software product. Most reliability models to estimate the reliability of software in the literature are based on the development lifecycle stages. However, in the maintenance phase, the software needs to be corrected for errors and to be enhanced for the requests from users. These decrease the reliability of software. Software Reliability Growth Models (SRGMs) have been applied successfully to model software reliability in development phase. The software reliability in maintenance phase exhibits many types of systematic or irregular behaviors. These may include cyclic behavior as well as long-term evolutionary trends. The cyclic behavior may involve multiple periodicities and may be asymmetric in nature. In this paper, SGRM has been adapted to develop a reliability prediction model for the software in maintenance phase. The model is established using maintenance data from a commercial shop floor control system. The model is accepted to be used for resource planning and assuring the quality of the maintenance work to the user.

• Journal of Information Technology Services
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• v.20 no.3
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• pp.57-73
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• 2021

Recently, online job websites have been activated as unemployment problems have emerged as social problems and demand for job openings has increased. However, while the online job platform market is growing, users have difficulty choosing their jobs. When users apply for a job on online job websites, they check various information such as job contents and recruitment conditions to understand the details of the job. When users choose a job, they focus on various details related to the job rather than simply viewing and supporting the job title. However, existing online job websites usually recommend jobs using only quantitative preference information such as ratings. However, if recommendation services are provided using only quantitative information, the recommendation performance is constantly deteriorating. Therefore, job recommendation services should provide personalized services using various information about the job. This study proposes a recommended methodology that improves recommendation performance by elaborating on qualitative preference information, such as details about the job. To this end, this study performs a topic modeling analysis on the job content of the user profile. Also, we apply LDA techniques to explore topics from job content and extract qualitative preferences. Experiments show that the proposed recommendation methodology has better recommendation performance compared to the traditional recommendation methodology.

• Education of Primary School Mathematics
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• v.23 no.4
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• pp.207-227
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• 2020

The demand for private education in Korea is steadily increasing every year, and the participation rate of private education is increasing as the grade goes down. In order to empirically verify the effectiveness of private education, it is necessary to analyze through longitudinal data that has been mainly investigated over a long period of time. This study investigated the longitudinal changes in mathematics academic achievement and participation time in mathematics private education using longitudinal data from 2013 (4th grade in elementary school) to 2017 (2nd grade in middle school) of the Seoul Education Longitudinal Study. The students were divided into groups in which mathematics academic achievement changed similarly as the grade went up, and the effect of mathematics academic achievement was examined according to the change of participation time in private mathematics education for each group. As a result of the study, it was found that the participation time of private math education of all students continuously increased from the 5th grade of elementary school to the 2nd grade of middle school, and the participation time of private math education by group was different. In addition, the effect of private tutoring by group was different according to the group.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.1
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• pp.29-42
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• 2019

In order to expand the qualitative aspects of public facility, this study used SNS data to derive user-oriented preference factors for public facilities and then were quantified in terms of supply side and demand side. To derive preference factor, LDA, one of topic modeling, was used and attraction index was calculated for each facility. In addition we analyzed spatial accessibility to measure the degree of service experience of users by using 2SFCA model. The study area covered public libraries of Seoul, Korea. As a result of study, five topics were extracted as preference factors for the public library: Circumstance, Scale of facility, Cultural program, Parenting, Books and materials. In particular topic of circumstance and parenting were newly derived preference factors unknown in previous studies. As a result of calculating attraction index for each library, the index of Songpa Library, Jungdok Library, and Namsan Library was high. Songpa library has received good evaluation in parenting factor, and Jungdok & Namsan library in circumstance factor. The accessibility of each region seems to better in center of Seoul where public libraries are crowded, but shrinking toward the outskirts. We expect that the proposed method will contribute to user-oriented public facility evaluation and policy decision making.