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The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform

Jeanmichel Oppert - One of the best experts on this subject based on the ideXlab platform.

  • 10 year cumulative and bidirectional associations of Domain specific physical activity and sedentary behaviour with health related quality of life in french adults results from the su vi max studies
    Preventive Medicine, 2016
    Co-Authors: Abdou Y Omorou, A Vuillemin, M Menai, Clotilde Latarche, Emmanuelle Kesseguyot, Pilar Galan, Serge Hercberg, Jeanmichel Oppert
    Abstract:

    Abstract Background The directionality of the associations of Domain-specific physical activity (PA) and sedentary behaviour (SB) with health-related quality of life (HRQoL) in adults remain insufficiently known. This study investigated the longitudinal associations of 10-year cumulative levels of PA and SB with HRQoL and the reverse associations. Methods A sample of 2093 (47.8% men) participants from a cohort of French adult (SU.VI.MAX) was included. Data were collected at 3 time points (1998, 2001 and 2007) using the Modifiable Activity Questionnaire (MAQ) for PA (leisure-time and occupational) and SB (screen-viewing, reading and total sitting time) and the DUKE Health Profile for HRQoL. The cumulative level (from 0 to 3) referred to the number of time points where a high PA level, high SB or good HRQoL was reported. Regression models examined the 10-year cumulative level of PA, SB as predictors of HRQoL and reverse associations. Results The 10-year cumulative level of high PA, both leisure-time and occupational, predicted a higher HRQoL while the 10-year cumulative level of high screen-viewing time and high total sitting time was associated with lower HRQoL. For the reverse association, cumulative level of good HRQoL predicted more leisure-time PA, less screen-viewing time and less total sitting time but was not related to occupational PA. Conclusion Relationships between PA, SB and HRQoL are complex and should not be oversimplified in one or the other direction. Taking into Account Domain-specific PA and SB in health promotion programs appears of prime importance to design interventions aiming at improving HRQoL.

Abdou Y Omorou - One of the best experts on this subject based on the ideXlab platform.

  • 10 year cumulative and bidirectional associations of Domain specific physical activity and sedentary behaviour with health related quality of life in french adults results from the su vi max studies
    Preventive Medicine, 2016
    Co-Authors: Abdou Y Omorou, A Vuillemin, M Menai, Clotilde Latarche, Emmanuelle Kesseguyot, Pilar Galan, Serge Hercberg, Jeanmichel Oppert
    Abstract:

    Abstract Background The directionality of the associations of Domain-specific physical activity (PA) and sedentary behaviour (SB) with health-related quality of life (HRQoL) in adults remain insufficiently known. This study investigated the longitudinal associations of 10-year cumulative levels of PA and SB with HRQoL and the reverse associations. Methods A sample of 2093 (47.8% men) participants from a cohort of French adult (SU.VI.MAX) was included. Data were collected at 3 time points (1998, 2001 and 2007) using the Modifiable Activity Questionnaire (MAQ) for PA (leisure-time and occupational) and SB (screen-viewing, reading and total sitting time) and the DUKE Health Profile for HRQoL. The cumulative level (from 0 to 3) referred to the number of time points where a high PA level, high SB or good HRQoL was reported. Regression models examined the 10-year cumulative level of PA, SB as predictors of HRQoL and reverse associations. Results The 10-year cumulative level of high PA, both leisure-time and occupational, predicted a higher HRQoL while the 10-year cumulative level of high screen-viewing time and high total sitting time was associated with lower HRQoL. For the reverse association, cumulative level of good HRQoL predicted more leisure-time PA, less screen-viewing time and less total sitting time but was not related to occupational PA. Conclusion Relationships between PA, SB and HRQoL are complex and should not be oversimplified in one or the other direction. Taking into Account Domain-specific PA and SB in health promotion programs appears of prime importance to design interventions aiming at improving HRQoL.

Yihchun Hu - One of the best experts on this subject based on the ideXlab platform.

  • signal jamming attacks against communication based train control attack impact and countermeasure
    arXiv: Cryptography and Security, 2018
    Co-Authors: Subhash Lakshminarayana, Jabir Shabbir Karachiwala, Sangyoon Chang, Girish Revadigar, Sristi Lakshmi Sravana Kumar, Yihchun Hu
    Abstract:

    We study the impact of signal jamming attacks against the communication based train control (CBTC) systems and develop the countermeasures to limit the attacks' impact. CBTC supports the train operation automation and moving-block signaling, which improves the transport efficiency. We consider an attacker jamming the wireless communication between the trains or the train to wayside access point, which can disable CBTC and the corresponding benefits. In contrast to prior work studying jamming only at the physical or link layer, we study the real impact of such attacks on end users, namely train journey time and passenger congestion. Our analysis employs a detailed model of leaky medium-based communication system (leaky waveguide or leaky feeder/coaxial cable) popularly used in CBTC systems. To counteract the jamming attacks, we develop a mitigation approach based on frequency hopping spread spectrum taking into Account Domain-specific structure of the leaky-medium CBTC systems. Specifically, compared with existing implementations of FHSS, we apply FHSS not only between the transmitter-receiver pair but also at the track-side repeaters. To demonstrate the feasibility of implementing this technology in CBTC systems, we develop a FHSS repeater prototype using software-defined radios on both leaky-medium and open-air (free-wave) channels. We perform extensive simulations driven by realistic running profiles of trains and real-world passenger data to provide insights into the jamming attack's impact and the effectiveness of the proposed countermeasure.

Hu Yih-chun - One of the best experts on this subject based on the ideXlab platform.

  • Signal Jamming Attacks Against Communication-Based Train Control: Attack Impact and Countermeasure
    2018
    Co-Authors: Lakshminarayana Subhash, Karachiwala, Jabir Shabbir, Chang Sang-yoon, Revadigar Girish, Kumar, Sristi Lakshmi Sravana, Yau, David K. Y., Hu Yih-chun
    Abstract:

    We study the impact of signal jamming attacks against the communication based train control (CBTC) systems and develop the countermeasures to limit the attacks' impact. CBTC supports the train operation automation and moving-block signaling, which improves the transport efficiency. We consider an attacker jamming the wireless communication between the trains or the train to wayside access point, which can disable CBTC and the corresponding benefits. In contrast to prior work studying jamming only at the physical or link layer, we study the real impact of such attacks on end users, namely train journey time and passenger congestion. Our analysis employs a detailed model of leaky medium-based communication system (leaky waveguide or leaky feeder/coaxial cable) popularly used in CBTC systems. To counteract the jamming attacks, we develop a mitigation approach based on frequency hopping spread spectrum taking into Account Domain-specific structure of the leaky-medium CBTC systems. Specifically, compared with existing implementations of FHSS, we apply FHSS not only between the transmitter-receiver pair but also at the track-side repeaters. To demonstrate the feasibility of implementing this technology in CBTC systems, we develop a FHSS repeater prototype using software-defined radios on both leaky-medium and open-air (free-wave) channels. We perform extensive simulations driven by realistic running profiles of trains and real-world passenger data to provide insights into the jamming attack's impact and the effectiveness of the proposed countermeasure.Comment: Proceedings of the 11th ACM Conference on Security & Privacy in Wireless and Mobile Networks (WiSec) - 201

Stefanie Lindstaedt - One of the best experts on this subject based on the ideXlab platform.

  • a network model approach to document retrieval taking into Account Domain knowledge
    LWA - Lernen Wissensentdeckung Adaptivität, 2006
    Co-Authors: Peter Scheir, Stefanie Lindstaedt
    Abstract:

    We preset a network model for context-based retrieval allowing for integrating Domain knowledge into document retrieval. Based on the premise that the results provided by a network model employing spreading activation are equivalent to the results of a vector space model, we create a network representation of a document collection for retrieval. We extended this well explored approach by blending it with techniques from knowledge representation. This leaves us with a network model for finding similarities in a document collection by content-based as well as knowledge-based similarities.