Catálogo de publicaciones - libros

This work provides non-contact optical technique to investigate the transverse vibration characteristics of laminate square plates in resonance. Most of the works on vibration analysis of plates published in the literature are analytical and numerical and very few experimental results are available. The edges of these laminated plates are free. Electronic Speckle Pattern Interferometry (ESPI) can obtain both resonant frequencies and mode shapes of vibrating plates simultaneously. Excellent quality of the interferometric fringe patterns for the mode shapes is obtained. Seven different composite plates with the same geometric configuration are investigated in this study.

-The present paper investigates the numerical modeling of the electro-mechanical impedance for smart plate structures partially treated with active constrained layer damping treatments. The example used is a smart cantilever plate structure containing a viscoelastic material (VEM) layer sandwiched between a piezoelectric constrained layer and the host vibrating plate. Comparisons are made between active constrained layer and active damping only and based on the resonance frequency amplitudes of the electrical admittance numerically evaluated at the surface of the piezoelectric model of the vibrating structures.

Quantum associative memories are derived from the Hopfield memory model under the assumption that the elements of the correlation weight matrix

This paper shows a motor imaginary based Brain-Computer Interface (BCI) virtual navigation system. The virtual navigation system is designed for motion disabled people to navigate and control between virtual environment as well as real environment. This system consists of the brain-computer interface using motor imagery brain signals, the communication module, the brain signal analyzer and the virtual world linked with a physical miniature model of real home environment. A preliminary user evaluation showed that our BCI-testbed produced a reasonable classification rate to be used in virtual reality and real world. In the near future, we will integrate this system in a ubiquitous computing environment.

- Image clustering analysis is one of the core techniques for image indexing, classification, identification and segmentation for image processing. On the basis of investigation on the laws of gray distribution of medical image, density function construction based medical image clustering analysis method is designed. For the special kind of data object – medical images, firstly its density function is constructed; secondly, a method of density function construction based on medical image clustering analysis and its implementation algorithm, that is, hill climbing, is offered; At last, abdomen medical images are used to do experiments according to those two algorithms. Experiment results show that medical image clustering on the ground of density function construction achieves good effects and can clearly express the content and semanteme of medical images.

Securing ad hoc networks represents a challenging issue, related to their very characteristics of decentralized architecture, lowcomplexity, and multiple hops communications. Even if several methods are available, this paper presents a novel approach to allow secret sharing of information at lower levels of the node protocol stack. In fact, secret sharing schemes provide a natural way of addressing security issues in ad hoc networks. To this aim, a flexible framework for secure end-to-end transmission of confidential information is proposed which exploits multipath source routing and hierarchical shares distribution. Such a goal is achieved by designing an ideal, perfect, and eventually verifiable secret sharing scheme based on Birkhoff polynomial interpolation and by establishing suitable hierarchies among independent paths.1

Secure Role-Based Access Control (SRBAC) is an entry protocol implemented to protect sensitive database information. An individual’s security clearance and role description will determine what privileges they are authorized. Prior research focused on a Mobile Secure Role Based Access Control (MS-Ro-BAC) Database, for wireless and wired access connectivity. “Ref. [4].” In order to implement a control procedure to protect sensitive database information, over wired or wireless communication channels, required a combination of new server and programming security implementations. Proprietary software was developed as a front end authentication when logging into the server and website databases; two levels of security decreased the chances of compromising the database system and design. “Ref [5].” An individual’s username, password, role description and security clearance determines what privileges they are authorized and what data they have access to. The wireless Iridium data connection proved not to be the choice of satellite communication service to best support the MS-Ro-BAC database system in a global environment. Nevertheless, the wired connectivity proved to be robust and stable, the world wide connectivity and data transmission between the database activities performed consistently at high level of proficiency “Ref. [3].” The capabilities provided by the MS-Ro-BAC research would support the ‘Global War on Terrorism’ and increase the security of US forces and Department of Defense Personnel around the world.

This study pioneers a new way to study the performance of hashing algorithms by evaluating their queueing behavior. We examine hashing as applied to URL routing used in Content Distribution Networks (CDNs). URL routing tables can be built as self-adjusting hash tables to reduce network bandwidth consumption in CDNs and at the same time take advantage of the high temporal locality of Web document requests. We show through a trace-driven simulation that the existing Aggressive hashing (based on move-to-front rule) improves upon H1 hashing (based on the transposition rule). Surprising results were found: even though the expected improvement in look-up time over H1 hashing is modest, the improvement from a queueing perspective appears to be very significant. The long range dependence in look-up time of H1 hashing contributes to its extreme queueing delay. This shows that using queueing delay as a means of evaluating hashing algorithms can be very insightful.

In this paper, we propose an enhancement on the SMAC protocol to improve its latency performance without compromising its energy consumption. The original SMAC provides an efficient solution for the energy consumption problem in Wireless Sensor Networks (WSNs) due to idle listening, but it has some latency problem especially in low duty cycle applications. TMAC was proposed to further reduce the energy consumption in SMAC and introduced the FRTS packet to solve the

An integrated IP over Optical Network controlled by the Generalized Multi-Protocol Label Switching (GMPLS) common control plane is believed to be a promising solution for the Next Generation Optical Internet. In this scenario, Multi-layer Traffic Engineering (MTE) can be improved in terms of transmission quality and traffic grooming. This paper proposes an integrated MTE scheme able to route IP traffic considering the potential power penalty of all-optical connections (for transmission quality purpose) and the network resource usage (for grooming purpose). The routing algorithm is executed on an integrated graph formed by both the physical and the logical topologies. This graph representation enables integrated Resource Reservation Protocol (RSVP) sessions that decrease the latency time. Via extensive simulations, the performance of this scheme in terms of connection requests success probability, resource usage and transmission quality is evaluated.