• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.211-216
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• 2015

Recently, because of the growth in the leisure industry and interest in health, the demand for bicycles has increased. In this research, considering the vertical load on a bike frame under static state conditions, the deflection and mass of the bike frame were minimized by satisfying the service condition and performing optimization. The thickness of the bicycle-frame tube was set to a design variable, and its sensitivity was confirmed by an analysis of means (ANOM). To optimize the solution, a response-surface-method (RSM) model was constructed using D-Optimal and central composite design(CCD). The optimization was performed using a non-dominant sorting genetic algorithm (NSGA-II), and the optimal solution was verified by finite-element analysis.

• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.739-751
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• 2020

Seoul public bike program facilitates access to bicycles and offers potential for greater mobility and health for users. Furthermore, it would have positive impacts on transport congestion, energy use, and the environment. Hence, it is important to find future rental locations by taking to account both bike-demand and regional imbalance. This paper first finds eligible candidates of rental locations with the required spatial conditions such as a sufficient sidewalk width and accessibility of bike pick-up vehicles. And then, estimates public bike daily usage for each selected location via random forest based on Seoul public bike historical usage, Seoul geographical features, regional characteristics, and populations. This study contributes to a better comprehension of the Seoul public bike program, and would be useful in determining new public bike rental locations.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.1-19
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• 2023

Bikes have recently emerged as an alternative to carbon neutrality. To understand the demand for public bikes, we endeavored to estimate travel frequency of public bike by considering the intermediate stops. Using the GPS trajectory data of 'Ttareungyi', a public bike service in Seoul, we identified a stay point and estimated travel frequency reflecting population, land use, and physical characteristics. Application of map matching and a stay point detection algorithm revealed that stay point appeared in about 12.1% of the total trips. Compared to a trip without stay point, the trip with stay point has a longer average travel distance and travel time and a higher occurrence rate during off-peak hours. According to visualization analysis, the stay points are mainly found in parks, leisure facilities, and business facilities. To consider the stay point, the unit of analysis was set as a hexagonal grid rather than the existing rental station base. Travel frequency considering the stay point were analyzed using the Zero-Inflated Negative Binomial (ZINB) model. Results of our analysis revealed that the travel frequency were higher in bike infrastructure where the safety of bike users was secured, such as 'Bikepath' and 'Bike and pedestrian path'. Also, public bikes play a role as first & last mile means of access to public transportation. The measure of travel frequency was also observed to increase in life and employment centers. Considering the results of this analysis, securing safety facilities and space for users should be given priority when planning any additional expansion of bike infrastructure. Moreover, there is a necessity to establish a plan to supply bike infrastructure facilities linked to public transportation, especially the subway.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.103-114
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• 2011

Usage of bicycle has been supported the universal reduction of energy consumption and $CO_2$. For the same purpose, new constructions for long length bike roads are planned in Korea. Recently, laboratory tests of physical properties and resistance against environmental loading about optimum mix design of roller compacted concrete, that have advantages of high structural performance by cement hydration and aggregate interlocking, simple construction procedure and low construction cost, are performed for the effective construction of new bike roads. However, properties of roller compacted concrete had different results between laboratory and field tests since it had different compaction method. Also, construction method of roller compacted concrete are not defined for the application of bike roads since it had different demand performance such as thin pavement thickness, low strength and etc with road pavements. Thus, in this experimental research was launched to evaluate the core properties, visual inspection, compaction ratio, water content, thickness reduction rate of roller compaction, skid resistance and roughness by experimental construction about variable mix proportion and compaction method based on laboratory test results. And construction method of roller compacted concrete pavement were suggested for the application of bike roads.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.157-167
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• 2011

Many problems, such as unexpected delay and collision with pedestrians or vehicles, occur generally at signalized intersections where bicycle users are frequently involved. These problems have hindered bicycle users from riding bicycles on urban highways. The aim of this study is to suggest proper traffic signal operation methods for safe and convenient highway crossing of bicycles. Three types of crossing methods at signalized intersections are proposed and analyzed: (1) indirect left turn, (2) direct left turn on an exclusive bicycle lane, and (3) direct left turn on a bicycle box. The VISSIM simulation tests were conducted based on fifty-four operation scenarios prepared by varying vehicle and bicycle traffic volumes. Both delay and the number of stops are used as the measures of effectiveness in the analysis. The results from the three-legged signalized intersections suggested that (1) the indirect left turn is appropriate when vehicle demand is high while bicycle demand is not, (2) direct left turn on an exclusive bicycle lane is appropriate when both vehicle and bicycle demands are high, and (3) direct left turn on a bicycle box is appropriate when both vehicle and bicycle demands are light.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.5
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• pp.169-178
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• 2021

Recently, a bike-sharing system (BSS) has become popular as a convenient "last mile" transportation. Rebalancing of bikes is a critical issue to manage BSS because the rents and returns of bikes are not balanced by stations and periods. For efficient and effective rebalancing, accurate traffic prediction is important. Recently, cluster-based traffic prediction has been utilized to enhance the accuracy of prediction at the station-level and the clustering step is very important in this approach. In this paper, we propose a k-means based clustering algorithm that overcomes the drawbacks of the existing clustering methods for BSS; indeterministic and hardly converged. By employing the centroid initialization and using the temporal proportion of the rents and returns of stations as an input for clustering, the proposed algorithm can be deterministic and fast.

• Korean Journal of Artificial Intelligence
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• v.10 no.1
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• pp.9-14
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• 2022

The demand for public bicycles operated by the Seoul Metropolitan Government is increasing every year. The size of the Seoul public bicycle project, which first started with about 5,600 units, increased to 3,7500 units as of September 2021, and the number of members is also increasing every year. However, as the size of the project grows, excessive budget spending and deficit problems are emerging for public bicycle projects, and new bicycles, rental office costs, and bicycle maintenance costs are blamed for the deficit. In this paper, the Azure Machine Learning Studio program and the Boosted Decision Tree Regression technique are used to predict the number of public bicycle rental over environmental factors and time. Predicted results it was confirmed that the demand for public bicycles was high in the season except for winter, and the demand for public bicycles was the highest at 6 p.m. In addition, in this paper compare four additional regression algorithms in addition to the Boosted Decision Tree Regression algorithm to measure algorithm performance. The results showed high accuracy in the order of the First Boosted Decision Tree Regression Algorithm (0.878802), second Decision Forest Regression (0.838232), third Poison Regression (0.62699), and fourth Linear Regression (0.618773). Based on these predictions, it is expected that more public bicycles will be placed at rental stations near public transportation to meet the growing demand for commuting hours and that more bicycles will be placed in rental stations in summer than winter and the life of bicycles can be extended in winter.

• Journal of Service Research and Studies
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• v.8 no.4
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• pp.53-75
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• 2018

Bicycle-sharing as a product service system in the sharing economy, its characteristic is that users can go to nearby places by the public bike at any time however they don't need to have their own bicycle. However, the service quality of bicycle-sharing and satisfaction of users continuously decrease with the rapid growth number of bicycle-sharing users in China. Based on the double diamond model and from the perspective of service design, this research studies the service experience of bicycle-sharing of Chinese users, focuses on the potential pain points of Chinese users when using the public bike, and designs the optimum proposal to promote users' satisfaction. According to the research result, the research builds a new concept which can satisfy users' demand for communication, enjoyment and option during the cycling. The experience of new service system of bicycle-sharing makes humanized and subconscious interaction possible.

• Journal of the Korean housing association
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• v.11 no.3
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• pp.87-98
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• 2000

This study derives problems of external space utilization site from on-site observation and questionnaire survey in order to suggest solutions for the problems. The main results are follows. First, fences as visual boundaries of apartment site play some negative roles - separation of space and heterogeneity of circumstance. This study suggests green fences to cure this problem. Second, residents want to change space use - ground to be used as green space or space for relaxation in stead of parking lots, elevator hall as social space, and underground as bike parks or health centers. Third, rooftop space, used as empty space or machine storage space, should be designed to be utilized as relaxation space by making easy to enter and exit.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.14-25
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• 2021

With the spread of COVID-19 and the government policy of social distancing, the demand for subways and buses is decreasing, whereas the demand for public bicycles and personal transportation is increasing. Hence, research is needed to understand the characteristics of this phenomenon and to prove the statistical reliability of the correlation between the subway and shared bicycle demands. In this study, the correlation between the number of confirmed COVID-19 cases and the replacement rate of subway and public bicycle demands was examined, but the statistical significance was not significant. However, during the period of September to December 2020, in which the number of confirmed COVID-19 cases in Seoul started to increase rapidly, there was a correlation between the number of confirmed COVID-19 cases and the replacement ratio. If the number of confirmed COVID-19 cases increases by more than a certain number, public bicycles are expected to play a significant role as alternates to the subways. It is expected that the role of public bicycles will increase, and that it is possible to suggest the direction of transportation operation and policy establishment for the continuation of COVID-19 countermeasures in field demonstration after elementary technology development. It is also expected that this study will suggest a direction for future development and policymaking.