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Brussels, Belgium

Scheers B.,Royal Military Academy RMA | Mahoney A.,Saab | Akermark H.,Saab
2012 Military Communications and Information Systems Conference, MCC 2012 | Year: 2012

Cognitive radio (CR) technology has to date not been adopted by the military even though more than a decade has passed since its inception. This paper describes how cognitive radio and associated dynamic spectrum management (DSM) procedures can be introduced in military tactical radio communication. CR and DSM address key challenges that face future military tactical radio communication and their successful introduction can reduce or even overcome current spectrum scarcity and deployment difficulty. A DSM roadmap is introduced where military users develop trust in, and experience with, these novel technologies in manageable steps. The first step in this DSM roadmap involves the introduction of a military band dedicated for CRs and subsequent steps gradually increase the spectrum that may be utilized for military cognitive operation. A high-level vision of how existing military spectrum management procedures will change in the future with the introduction of DSM is also presented resulting in a significant reduction in the workload of spectrum management personnel. © 2012 Military Univ of Tech.

Van Puyvelde M.,Vrije Universiteit Brussel | Loots G.,Vrije Universiteit Brussel | Loots G.,Bolivian Catholic University | Gillisjans L.,Vrije Universiteit Brussel | And 3 more authors.
Infant Behavior and Development | Year: 2015

This study reports a cross-cultural comparison of the vocal pitch patterns of 15 Mexican Spanish-speaking and 15 Belgian Flemish-speaking dyads, recorded during 5. min of free-play in a laboratory setting. Both cultures have a tradition of dyadic face-to-face interaction but differ in language origins (i.e., Romanic versus Germanic). In total, 374 Mexican and 558 Flemish vocal exchanges were identified, analyzed and compared for their incidence of tonal synchrony (harmonic/pentatonic series), non-tonal synchrony (with/without imitations) and pitch and/or interval imitations. The main findings revealed that dyads in both cultures rely on tonal synchrony using similar pitch ratios and timing patterns. However, there were significant differences in the infants' vocal pitch imitation behavior. Additional video-analyzes on the contingency patterns involved in pitch imitation showed a cross-cultural difference in the maternal selective reinforcement of pitch imitation. The results are interpreted with regard to linguistic, developmental and cultural aspects and the 'musilanguage' model. © 2015 Elsevier Inc.

Scheers B.,Royal Military Academy RMA
Proceedings - IEEE Military Communications Conference MILCOM | Year: 2013

To facilitate the introduction of Dynamic Spectrum Access (DSA) technology and associated dynamic spectrum management (DSM) procedures in military tactical radio communication, a roadmap was presented to NATO CaP3 military session in Oct 2012. The main objective of the roadmap was to create a dedicated band for cognitive radio, in the hope that this would take away uncertainties about spectrum regulations and be a sufficient incentive for military communication industry to start investing and developing products. This paper describes the proposed roadmap and formulates the critics of the NATO spectrum managers (CaP3) on this proposition. Taking into account the remarks of CaP3, a possible way ahead is described. The most promising idea is to create a Military dual-priority band that would take into account the existing saturation of the VHF/UHF band, and meanwhile create a clear spectrum access model for future DSA systems. © 2013 IEEE.

Le Nir V.,Royal Military Academy RMA | Scheers B.,Royal Military Academy RMA
2012 Military Communications and Information Systems Conference, MCC 2012 | Year: 2012

Cognitive radio is envisioned to solve the problem of spectrum scarcity in military networks and to autonomously adapt to rapidly changing radio environment conditions and user needs. Dynamic spectrum management techniques are needed for the coexistence of multiple cognitive tactical radio networks. Previous work has investigated the iterative waterfilling algorithm (IWFA) as a possible candidate to improve the coexistence of such networks. It has been shown that adding a constraint on the number of transmitter's sub-channels improves the convergence of IWFA. In this paper, we propose an adaptive orthogonal frequency division multiple access (OFDMA) physical (PHY) and medium access control (MAC) for the coexistence of multiple cognitive tactical radio networks. The proposed scheme is implemented on universal software radio peripheral (USRP) platforms using Qt4/IT++ and the USRP hardware driver (UHD) application programming interface (API). © 2012 Military Univ of Tech.

Spranghers K.,Vrije Universiteit Brussel | Vasilakos I.,Vrije Universiteit Brussel | Lecompte D.,Royal Military Academy RMA | Sol H.,Vrije Universiteit Brussel | Vantomme J.,Royal Military Academy RMA
International Journal of Impact Engineering | Year: 2013

Protection of buildings against explosions due to terrorism actions or accidents is a growing concern in civil engineering. Full-field measuring techniques as well as finite element simulations are two valuable tools in the hands of engineers to understand the structural mechanisms during blast load events. The research leading to this article is motivated by the fact that only limited knowledge about finite element simulations and experimental validation of structures under free air explosions seems to be available. This article investigates the benefits and accuracy of a finite element simulation of a blast loaded thin aluminum plate by validating the results with small-scale blast loading experiments. Experimental data obtained from 3D high-speed digital image correlation, during the first 7 ms with a frame rate of 25,000 frames per second, is compared with results obtained from the finite element analysis. The influence of different parameters (amongst others: the element type, element size and integration method) with respect to the accuracy of the finite element results is investigated. It is shown that for the modeling of the deformation of the investigated thin plate, the use of shell elements is allowed as the transverse shear strains appear to be sufficiently small. Furthermore, it is concluded that the use of an explicit integration scheme instead of an implicit scheme dramatically reduces the computational effort without significant loss of accuracy. © 2012 Elsevier Ltd. All rights reserved.

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