• Title/Summary/Keyword: Smart Safe City

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A Study on Applicability of Embedded Smart Sensor for Concrete Curing Monitoring (콘크리트 양생 강도 모니터링을 위한 매립형 지능형 센서의 적용성 연구)

  • Park, Seung-Hee;Kim, Dong-Jin;Hong, Seok-Inn;Lee, Chang-Gil
    • Journal of the Korea Concrete Institute
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    • v.23 no.2
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    • pp.219-224
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    • 2011
  • In this study, a piezoelectric smart sensor that can be embedded inside of concrete structures is developed to investigate the early stage of concrete curing. A waterproof coating is used to protect the piezoelectric sensor from moistures of concrete mixture. Also, a mortar case is utilized to encapsulate the sensor to protect it from impact loads. To estimate the strength of concrete, a self-sense guided-wave actuated sensing technique is applied. In the guided wave, its velocity is varied according to the mechanical properties of concrete such as modulus of elasticity. Because modulus of elasticity directly affects the strength of concrete, the guidedwave's velocity also affects the concrete strength development. To verify the feasibility of using the proposed approach, the smart sensor was embedded into a 100MPa concrete cylinder and the self-sense guided wave is continuously measured throughout the curing process. The measurements showed that the propagation time (TOF) of the measured guided waves gradually decreased as the curing age increased. Especially, at the early age of the curing process, the variation of the TOF was very significant. Furthermore, the results showed that there is a linear relationship between the TOF of the self-sense guided waves and the strength of concrete existed. It is safe to conclude that the proposed approach can be used very effectively in monitoring of the strength development of high strength concrete structures.

Preference Analysis for Location Based Services on Smartphone Users; Focusing on the H University Students in Daejeon Area (스마트폰 사용자의 위치기반 서비스에 대한 선호도 분석: 대전지역 H 대학교 학생 설문을 중심으로)

  • Nam, Soo-Tai;Jin, Chan-Yong
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.10 no.4
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    • pp.59-66
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    • 2015
  • The rapid development of information communication technology(ICT) is born opportunities of business venturing and many items of start-up. On the smart media era, there are a lot of location based services. Thus we researched to find which factors impact location based constructs on smartphone environment in this study. We have conducted a preference analysis of the influencing factors for location based constructs for our study. In first steps, based constructs that were already known by empirical studies were categorized information, entertainment, safe&emergency, navigation&tracking and advertising&commerce. In second steps, the preference relationship among the categorized constructs were analyzed using AHP(analytic hierarchy process) technique. Participants of this study were 106 students H university in Daejeon-city during 2014. 10. 11 to 2014. 10. 25. The result of the analysis might be summarized that the chatting(0.170) has the highest preference among the above constructs. Based on these findings, several theoretical and practical implications were suggested and discussed.

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Research on Relay Selection Technology Based on Regular Hexagon Region Segmentation in C-V2X

  • Li, Zhigang;Yue, Xinan;Wang, Xin;Li, Baozhu;Huang, Daoying
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3138-3151
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    • 2022
  • Traffic safety and congestion are becoming more and more serious, especially the frequent occurrence of traffic accidents, which have caused great casualties and economic losses. Cellular Vehicle to Everything (C-V2X) can assist in safe driving and improve traffic efficiency through real-time information sharing and communication between vehicles. All vehicles communicate directly with Base Stations (BS), which will increase the base station load. And when the communicating vehicles are too far apart, too fast or there are obstacles in the communication path, the communication link can be unstable or even interrupted. Therefore, choosing an effective and reliable multi-hop relay-assisted Vehicle to Vehicle (V2V) communication can not only reduce the base station load and improve the system throughput but also expand the base station coverage and improve the communication quality of edge vehicles. Therefore, a communication area division scheme based on regular hexagon segmentation technology is proposed, a relay-assisted V2V communication mechanism is designed for the divided communication areas, and an efficient communication link is constructed by selecting the best relay node. Simulation results show that the scheme can improve the throughput of the system by nearly 55% and enhance the robustness of the V2V communication link.