• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.17-25
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• 2017

Vertical reaction force between ground and tire is an important parameter determining the ground behavior characteristics of aircraft. This parameter can be used to calculate the lateral force and friction. However, it is hard to obtain this parameter in real-time when the aircraft is taxiing. Therefore, pre-analysis of ground behavior and vertical reaction force should be conducted using ground simulation results to prevent rollover or hazardous scenarios. In this paper, a Landing Gear and Full-Aircraft model was constructed using VI-Aircraft S/W. The roll behavior of aircraft was analyzed using steering simulation results compared with taxi-test data.

• Journal of Korean Society for Quality Management
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• v.46 no.4
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• pp.923-938
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• 2018

Purpose: O2O service are becoming popular in various industries such as food delivery and taxi. This research explores how users' motivation of O2O service influence customer loyalty through expectation-confirmation and satisfaction. this study attempts to explore the motivation factor (i.e. pricing, enjoyment, immediately, social influence) and to empirically examine the relationships between those and users' loyalty to O2O service. Methods: To test the proposed research model, a survey research methodology was used. Paper survey was distributed to O2O service users in Korea. A total of 198 data were used for the analysis. Structural equation modeling was used to test hypotheses. Results: According to our findings, this study found that satisfaction was positively influenced by users' motivation factors. all hypotheses about the effect of motivation on expectation-confirmation were statistically not significant. Conclusion: O2O service providers should consider the results of this study to satisfy users' expectations and satisfaction for building a better O2O market.

• Child Health Nursing Research
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• v.5 no.2
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• pp.136-150
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• 1999

The subjects, under 18 old, 2,694 children who visited ER during 1998, were surveyed by the Triage and other statitical data. The results were as follows 1. The male to female ratio was 1.7 : 1, and the toddler(1-4 old) was the majority. 2. Triage ; critical 1.3%, acute 14.6%, urgent 29.5%, nonemergent 54.6%. 3. The reasons of visiting ER ; 1) The children had diseases(46.5%), injury (36.9%), TA(5.6%) and toxication(1.0%). 2) In diseases, male to female ratio was 1.5 : 1 and in injury, male to female was 2 : 1. 3) Among the children having in TA, 12-18 old groups was the majority(34.9%). 4. The time of visiting : the 20:00 - 22:00 was the majority(16.9%). 5. By monthly and seasonal distribution ; Jan. (9.7%), Mar. and May(9% respectively, Dec. and July(6.7%) respectively. The children who visted ER in spring and autumn showed higher portion than those of summer and winter. 6. Results ; admission(27.4%), discharge(68.4%), operations(2.8%), and DOA and DAA(0.4%), The mortality of the infancy and toddler groups was 83.3%. The infancy group showed the highest rate of admission. 7. The time of staying in ER ; 1-2 hrs was the major group(23.3%) and the average was 4.6 hours. 8. By clinical departments ; Ped. was 34.4%, PS was 20.8%, Dental Surgery was 10.3% and Dermatology was 0.9%. 9. The types of visting ; the group who visited by themselves was 80%, transfer from the primary and secondary clinic was 17% and OPD was 3.0%. 10. The traffic means . by the own cars and taxi were 87.6%, by hospital ambulance was 6.1% and by 119 ambulance was 4.3%.

• Knowledge Management Research
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• v.21 no.1
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• pp.175-195
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• 2020

The development of platform service based on the information and communication technology has revolutionized patterns of commercial transactions, driving the growth of global economy. Furthermore, the radical advancement of artificial intelligence(AI) presents the huge potential to innovate almost all the industrial and economic activities. Given these technological developments, the goal of this paper is to investigate AI's impact on the platform service innovation as well as its influence on the business performance. For the goal, this paper presents the review of the types of service innovation, the nature of platform services, and technological characteristics of leading AI technologies, such as chatbot and recommendation system. As an empirical study, this paper performs a multiple case study of Kakao Group which is the leading mobile platform service with the most advanced AI in Korea. To understand the role and effect of AI on Kakao platform service, this study investigated three cases, including chatbot agent of Kakao Bank, Smart Call service of Kakao Taxi, and music recommendation system of Kakao Mellon. The analysis results of the case study show that AI initiated innovations in platform service concepts, service delivery, and customer interface, all of which lead to a significant decrease in the transaction costs and the personalization of services. Finally, for the successful development of AI, this research emphasizes the significance of the accumulation of customer and operational data, the AI human capital, and the design of R&D organization.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.45-54
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• 2008

This paper designs and Implements a connectivity analyzer for the hybrid vehicular network based on the real-life movement history data achieved from the Taxi telematics system currently in operation, aiming at providing a useful guideline and information to build a telematics network. The simulator traces the location of each vehicle, sets the vehicle type, either gateway or normal, decides whether it can be connected to a mobile gateway, keeps track of status of the vehicle, and calculates the duration of disconnected state. With this analysis considering the transmission range and gateway ratio, we can decide the cost-effective number of mobile gateways having both cellular and ad-hoc network interfaces, and buffer space requirement based on the measured disconnection time and message generation ratio.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.118-133
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• 2020

Research interest in the Mobility-as-a-Service (MaaS) concept for enhancing users' mobility experience is increasing. In particular, dynamic pricing techniques based on reinforcement learning have emerged since adjusting prices based on the demand is expected to help mobility services, such as taxi and car-sharing services, to gain more profit. This paper provides a simulation framework that considers more practical factors, such as demand density per location, preferred prices, the distance between users and drivers, and distance to the destination that critically affect the probability of matching between the users and the mobility service providers (e.g., drivers). The aforementioned new practical features are reflected on a data structure referred to as the Matching Matrix. Using an efficient algorithm of computing the probability of matching between the users and drivers and given a set of precisely identified high-demand locations using HDBSCAN, this study developed a better reward function that can gear the reinforcement learning process towards finding more realistic dynamic pricing policies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.679-686
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• 2012

KTX step 1 April 2004, after the opening, the second phase of the project was opened in November 2010. High-speed rail after the opening and continue to increase the demand of high-speed rail, Have the speed of competitive advantage compared too the means of transportation. The opening of these high-speed rail has led to changes of the move, the company's position, and the spatial structure of the population of reorganization, such as the social, economic, transportation. In this study, survey data using the High Speed Rail Station EMME/2 of the program to take advantage of the 2-Dimentional Blancing trip distribution to investigate the passage through the trip distribution by the estimation of the parameters of the model to estimate the distribution of the means of access and high-speed rail station to reproduce and Analysis of the results by means of access parameters (${\theta}$) autos 0.0395, buses 0.0390, subway 0.0650, taxi 0.0415, the frequency distribution (Trip Length Frequency Distribution: TLFD) were analyzed survey data value model with the results of comparing $R^2$ cars analysis and model values similar survey data 0.909 bus 0.923, subway 0.745 to 0.922, taxi, F test P value analysis is smaller than 0.05 at the 95% confidence level as a note that was judged to have been. Trip frequency distribution analysis, but in the future, set the unit to 5km-trip frequency distribution middle zone Units from small zone units (administrative district) segmentation research is needed, and can reflect the trip distance 0~5 km interval combined function to take advantage of the gravity model and the 3-Dimentional Blancing applied research is needed to be considered.

• Informatization Policy
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• v.27 no.2
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• pp.66-83
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• 2020

Local issues that occur in cities typically garner great attention from the public. While local governments strive to resolve these issues, it is often difficult to effectively eliminate them all, which leads to complaints. In tackling these issues, it is imperative for local governments to use big data to identify the nature of complaints, and proactively provide solutions. This study applies the LDA topic modeling technique to research and analyze trends and patterns in complaints filed online. To this end, 9,625 cases of online complaints submitted to the city of Busan from 2015 to 2017 were analyzed, and 20 topics were identified. From these topics, key topics were singled out, and through analysis of quarterly weighting trends, four "hot" topics(Bus stops, Taxi drivers, Praises, and Administrative handling) and four "cold" topics(CCTV installation, Bus routes, Park facilities including parking, and Festivities issues) were highlighted. The study conducted big data analysis for the identification of trends and patterns in civil affairs and makes an academic impact by encouraging follow-up research. Moreover, the text mining technique used for complaint analysis can be used for other projects requiring big data processing.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.19-32
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• 1999

In this study, the trip characteristics of workers in the city are systematically analyzed. The trip behaviors and socioeconomic characteristics of workers are analyzed using Person Trip Survey Data of 1988 and 1992 in Taegu Metropolitan area. With the results of behavioral analyses, the daily travel pattern of workers is shown as one tour contained two trips and it is relatively simple and stable. Also the rate using the same mode in a day is Presented as high ratio. So, it can be explained that the choice of worker\`s first trip is fixed his/her travel mode for his/her daily travel mode. Based on these analyses, the mode choice model for workers is developed by applying the Multi-nominal Logit Model with the choice set of bus, taxi, and car. The explanatory variables of this model include sex, age, auto, travel time, and cost. Empirical tests of the model show encouraging results. After that, the temporal transferability of the model is examined by the Pairwise t-test and five indexes far the model of 1988 and 1992. The results of examination are satisfied with each significance level of the explanatory variables and five indexes. Therefore. it can be concluded that the temporal transferability of this model developed in this study is resonable.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.329-342
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• 2020

In this paper, we analyzed the requirements for the application of UAM, a new concept to solve the traffic congestion in large cities. First, the current domestic and foreign status of research and development related to UAM was investigated and the pros and cons and the time required for each mission radius were analyzed for various configurations of aircraft being commercialized. In addition, in order to analyze the market acceptance of the UAM, the individual's consciousness and reliability requirements were identified and safety requirements were analyzed through accident rate data for each aircraft type. Because it operates in a densely populated urban area, requirement analyses on noise and exhaust, which are environmental factors that can affect the community were performed, and requirements related to aircraft performance, certification standards, and airworthiness standards of FAA and EASA were also analyzed.