• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.688-696
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• 2013

In wireless sensor networks, real-time applications have to ensure the timely delivery of real-time data. Recently, OMLRP (On-demand Multi-hop Look-ahead Routing Protocol) has been proposed to improve the timeliness of wireless sensor networks. The protocol needs initialization time to establish multi-hop information based routing path because it performs incremental look-ahead of the information. Consequently, the protocol deteriorates DDSR (Deadline Delivery Success Ratio) as an event moves because it takes little consideration of event mobility. In this paper, we proposed a Real-time Routing for Events Mobility (RREM) which exploits a data redirection in order to improve the DDSR of moving events. Instead of recollecting muti-hop look-ahead information, the RREM redirects the data to a sensor node holding the information collected in a previous round. We verify the timeliness and energy efficiency of RREM using various MatLab simulations.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.481-487
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• 2023

Recently, interest in UAM (Urban Air Mobility) has surged as a critical solution to urban traffic congestion and air pollution issues. However, efficient UAM operation requires accurate 3D Point Cloud data processing, particularly in separating the ground and objects. This paper proposes and validates a method for effectively separating ground and objects in a UAM environment, taking into account its dynamic and complex characteristics. Our approach combines attitude information from MEMS sensors with ground plane estimation using RANSAC, allowing for ground/object separation that isless affected by GPS errors. Simulation results demonstrate that this method effectively operates in UAM settings, marking a significant step toward enhancing safety and efficiency in urban air mobility. Future research will focus on improving the accuracy of this algorithm, evaluating its performance in various UAM scenarios, and proceeding with actual drone tests.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.239-246
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• 2017

Communications for mobile sink groups such as rescue teams or platoons bring about a new challenging issue for handling group mobility in wireless sensor networks. Recently, a group region-based approach has been proposed to send data to a mobile sink group. However, it uses excessive flooding for 3 steps (group region discovery, region information notification, and data dissemination) to support mobile sink group. Thus, it causes high energy consumption and data delivery failure. Moreover, its per-sink mobility supporting scheme makes energy consumption and data delivery failure more serious. Thus, this paper proposes an Energy-efficient and Reliable Mobile Group communication protocol (ERMG) to support a mobile sink group, which exploits a virtual grid structure. For the group region discover and notification and the data dissemination, ERMG uses communications with only cell heads of grid cells that manages group sinks. ERMG also uses a per-grid based scheme to support sink mobility. Simulation results show that ERMG has 30% less energy consumption and 6% more desired delivery deadline success ratio than the existing protocols.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.151-159
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• 2017

This study deals with characteristics and risk of a PM based on user survey result, road driving test and data analysis of PM accident. Text mining method is applied to extract PM accident data from Big Data, which are claim data of private insurance company. Road driving test and survey on safety, convenience, noise, overtake ability, steering ability, and climbing ability of PM are performed to evaluate user's safety and convenience considering domestic road condition. As the result of claim data analysis, annual average increase rate of PM accident is 47.4% and average compensation of personal mobility is higher than that of bicycle by maximum 1.5 times. 79.8% of PM accident is self-caused accident due to unskilled driving and age-specific diagnosis rate of driver over 60 is higher than that of under 60. Diagnosis rate of over 60 at lower limb, foot, rib and spine is especially higher than that of under 60. As the result of road driving test and user survey, satisfaction level on safety and convenience of PM is evaluated as close to that of bicycle and satisfaction level of PM is increased after boarding. Overtake ability, steering ability, and climbing ability of PM are evaluated as same or better than that of bicycle but warning equipment to pedestrian or bike such as horn is required because noise level of PM during driving is too low. Finally, user survey result shows that bicycle road is suitable for PM and safety standard, advance-education and insurance are required for PM. It is suggested that drivers' license for PM can be replaced by advance-education. Results of this study can be used to prepare safety measures and legal basis for PM operation.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.135-142
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• 2021

Estimating the locations of workers in a shipyard is beneficial for a variety of applications such as selecting potential forwarders for transferring data in IoT services and quickly rescuing workers in the event of industrial disasters or accidents. In this work, we propose a human movement stream processing system for estimating worker locations in shipyards based on Apache Spark and TensorFlow serving. First, we use Apache Spark to process location data streams. Then, we design a worker location prediction model to estimate the locations of workers. TensorFlow serving manages and executes the worker location prediction model. When there are requirements from clients, Apache Spark extracts input data from the processed data for the prediction model and then sends it to TensorFlow serving for estimating workers' locations. The worker movement data is needed to evaluate the proposed system but there are no available worker movement traces in shipyards. Therefore, we also develop a mobility model for generating the workers' movements in shipyards. Based on synthetic data, the proposed system is evaluated. It obtains a high performance and could be used for a variety of tasksin shipyards.

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.555-563
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• 2011

Osteoarthritis (OA) and rheumatoid arthritis (RA) are most popular types of arthritis in Korea. This study compared health-related quality of life (HRQoL) of homedwelling people with OA and RA in Korea. Data were drawn from the Korean nationwide representative survey. Subjects were 3,352 people with arthritis over 19 years of age (2,953 OA respondents and 399 RA respondents). Good HRQoL in OA respondents was dierentiated with limitation of mobility, perceived health status, age, economic status, presence of arthralgia, gender, medical coverage, and educational level. Good HRQoL in RA respondents was dierentiated with limitation of mobility, perceived health status, economic status, educational status, and presence of arthralgia. In conclusion, HRQoL and predictors of good HRQoL among people with arthritis diers for OA or RA. These results can be of use in development of health programs and clinical interventions for community-dwelling people with arthritis.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.187-196
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• 2021

The mobility handicapped are representative socially vulnerable people who account for a high percentage of our society. Due to the recent development of technology, personalized welfare technologies for the socially vulnerable are being studied, but it is relatively insufficient compared to the general people. In this study, we intend to implement a personalized restaurant recommendation system for the mobility handicapped. To this end, a hybrid recommendation system was implemented by combining the data of special transportation boarding and alighting history (7,153 cases) and information of Daegu Food restaurants (955 cases). In order to evaluate the effectiveness of the implemented recommendation system, we conducted performance comparisons with existing recommendation systems by prediction error rate and recommendation coverage. As a result of the analysis, the performance was higher than that of the existing recommendation system, and the possibility of a personalized restaurant recommendation system for the mobility handicapped was confirmed. In addition, we also confirmed the correlation in which similar restaurants are recommended in some types of the mobility handicapped. As a result of this study, it is judged that it will contribute to the use of restaurants with high satisfaction for the mobility handicapped, and the limitations of the study are also presented.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.375-381
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• 2020

The purpose of this study is to observe the meaning of the movement recognized by the millennials to derive the direction of the future mobility service strategy according to the change in the mobility paradigm. To do this, the concept of mobility was understood and related cases were analyzed. The characteristics of the millennials were theoretically summarized, and an in-depth interviews were carried out with 25 Korean millennials to analyze the emotion. As a result, it was observed that mobility is not just a movement, but a movement with a pleasant experience for them, and its meaning is being extending as an experiencing good that satisfied emotions, which makes life luxurious. To establish a mobility service strategy that satisfies them First, it is necessary to make an effort to curate a mobility life suited to different emotions. Second, a strategy is required to show the language and image with emotion as a service. Third, it is necessary to play the role of an expert leading the future mobility life to be realized through connection with various fields. We expect that this study will be used as fundamental data for establishing a future mobility service strategy.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.47-48
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• 2003

This new family of portable real time SEQUENTIAL MOBILITY PARTICLE COUNTER and SIZER (SMPS+C) is designed for mobility and easy field use. An integrated battery assures hours of operation, a data logger system storage of all optioned results and a user friendly powerful software easy operation. This technology not only simplifies the SMPS operation, but it permits new on site application monitoring up to a remote wireless telephone operation. (omitted)

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.217-219
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• 2001

WLAN은 다양한 정보와 자원을 공유할 수 있게 하는 LAN의 장점과, 제약 없는 연결성 제공이라는 편리성을 동시에 제공하고, 신뢰성 있는 data전송뿐만 아니라 유연성과 설치의 용이성을 장점으로 갖고 있다. 그러나 WLAN 이용하여 여러 어플리케이션을 사용할 때 제기되는 문제로 WLAN은 셀룰라 폰의 soft handover와 같은 mobility가 완전하게 지원되지 않으므로 WLAN 환경에서 VoIP 서비스 같은 실시간 서비스에 제약이 있다는 단점이 있다. 본 논문에서는 WLAN의 제약을 극복하기 위해 WLAN환경에서 이동단말의 이동성을 지원하기 위한 handover 방안을 제시하였다.