An observer-based vaccination control law for an SEIR epidemic model based on feedback linearization techniques for nonlinear systems

This paper presents a vaccination strategy for fighting against the propagation of epidemic diseases. The disease propagation is described by an SEIR (susceptible plus infected plus infectious plus removed populations) epidemic model. The model takes into account the total population amounts as a refrain for the illness transmission since its increase makes the contacts among susceptible and infected more difficult. The vaccination strategy is based on a continuous-time nonlinear control law synthesised via an exact feedback input-output linearization approach. An observer is incorporated into the control scheme to provide online estimates for the susceptible and infected populations in the case when their values are not available from online measurement but they are necessary to implement the control law. The vaccination control is generated based on the information provided by the observer. The control objective is to asymptotically eradicate the infection from the population so that the removed-by-immunity population asymptotically tracks the whole one without precise knowledge of the partial populations. The model positivity, the eradication of the infection under feedback vaccination laws and the stability properties as well as the asymptotic convergence of the estimation errors to zero as time tends to infinity are investigated.

Analytical efficiency evaluation of a network mobility management protocol for Intelligent Transportation Systems

One of the major concerns in an Intelligent Transportation System (ITS) scenario, such as that which may be found on a long-distance train service, is the provision of efficient communication services, satisfying users' expectations, and fulfilling even highly demanding application requirements, such as safety-oriented services. In an ITS scenario, it is common to have a significant amount of onboard devices that comprise a cluster of nodes (a mobile network) that demand connectivity to the outside networks. This demand has to be satisfied without service disruption. Consequently, the mobility of the mobile network has to be managed. Due to the nature of mobile networks, efficient and lightweight protocols are desired in the ITS context to ensure adequate service performance. However, the security is also a key factor in this scenario. Since the management of the mobility is essential for providing communications, the protocol for managing this mobility has to be protected. Furthermore, there are safety-oriented services in this scenario, so user application data should also be protected. Nevertheless, providing security is expensive in terms of efficiency. Based on this considerations, we have developed a solution for managing the network mobility for ITS scenarios: the NeMHIP protocol. This approach provides a secure management of network mobility in an efficient manner. In this article, we present this protocol and the strategy developed to maintain its security and efficiency in satisfactory levels. We also present the developed analytical models to analyze quantitatively the efficiency of the protocol. More specifically, we have developed models for assessing it in terms of signaling cost, which demonstrates that NeMHIP generates up to 73.47% less signaling compared to other relevant approaches. Therefore, the results obtained demonstrate that NeMHIP is the most efficient and secure solution for providing communications in mobile network scenarios such as in an ITS context.

Biologically-inspired data decorrelation for hyper-spectral imaging

Hyper-spectral data allows the construction of more robust statistical models to sample the material properties than the standard tri-chromatic color representation. However, because of the large dimensionality and complexity of the hyper-spectral data, the extraction of robust features (image descriptors) is not a trivial issue. Thus, to facilitate efficient feature extraction, decorrelation techniques are commonly applied to reduce the dimensionality of the hyper-spectral data with the aim of generating compact and highly discriminative image descriptors. Current methodologies for data decorrelation such as principal component analysis (PCA), linear discriminant analysis (LDA), wavelet decomposition (WD), or band selection methods require complex and subjective training procedures and in addition the compressed spectral information is not directly related to the physical (spectral) characteristics associated with the analyzed materials. The major objective of this article is to introduce and evaluate a new data decorrelation methodology using an approach that closely emulates the human vision. The proposed data decorrelation scheme has been employed to optimally minimize the amount of redundant information contained in the highly correlated hyper-spectral bands and has been comprehensively evaluated in the context of non-ferrous material classification

Influence of Humidity on Fiber Bragg Grating Sensors

We demonstrate the influence of the relative humidity (RH) on the wavelength of fiber Bragg grating sensors (FBGS), performing tests with five FBGS at different humidity and temperature conditions. These tests were performed in a climate chamber whose RH changes according to a scheduled profile from 30% to 90%, in steps of 10%. These profiles were repeated for a wide range of temperatures from to , in steps of . Two different types of instrumentation methods have been tested, spot welding and epoxy bonding, in two different materials, steel and carbon fiber reinforced polymer (CFRP). We discuss the results for each type of sensor and instrumentation method by analyzing the linearity of the Bragg wavelength with RH and temperature.

Variações sobre liberdade: estudo do conceito de liberdade no pensamento metafísico de Descartes

O objetivo desta dissertação é examinar alguns aspectos da doutrina da liberdade humana no pensamento metafísico de Descartes. Através do exame do conceito cartesiano da liberdade humana nas Meditações, nos Princípios e na correspondência com Mesland, pretende-se averiguar se Descartes modifica esse conceito ao longo de sua obra e, por conseguinte, se é possível ou não aceitar a tese da evolução deste conceito. A abordagem de tal questão leva em conta, além da análise dos textos de Descartes, as interpretações mais representativas sobre o assunto.

Lau cavity and phase locking of laser arrays

The Lau cavity is the self-imaging cavity with a phase corrector under the Lau reimaging condition. The author proposes the use of the Lau cavity to utilize both the Talbot and the Lau effects for phase locking one-dimensional and two-dimensional diode-laser arrays into a single-lobe coherent beam. Analyses on the self-reproducing of a coherent lasing field and the reimaging of initial incoherent radiation are given.

A uniform phase representation for the harmonic model in speech synthesis applications

Feature-based vocoders, e.g., STRAIGHT, offer a way to manipulate the perceived characteristics of the speech signal in speech transformation and synthesis. For the harmonic model, which provide excellent perceived quality, features for the amplitude parameters already exist (e.g., Line Spectral Frequencies (LSF), Mel-Frequency Cepstral Coefficients (MFCC)). However, because of the wrapping of the phase parameters, phase features are more difficult to design. To randomize the phase of the harmonic model during synthesis, a voicing feature is commonly used, which distinguishes voiced and unvoiced segments. However, voice production allows smooth transitions between voiced/unvoiced states which makes voicing segmentation sometimes tricky to estimate. In this article, two-phase features are suggested to represent the phase of the harmonic model in a uniform way, without voicing decision. The synthesis quality of the resulting vocoder has been evaluated, using subjective listening tests, in the context of resynthesis, pitch scaling, and Hidden Markov Model (HMM)-based synthesis. The experiments show that the suggested signal model is comparable to STRAIGHT or even better in some scenarios. They also reveal some limitations of the harmonic framework itself in the case of high fundamental frequencies.

Coincidence point theorems in quasi-metric spaces without assuming the mixed monotone property and consequences in G-metric spaces

In this paper, we present some coincidence point theorems in the setting of quasi-metric spaces that can be applied to operators which not necessarily have the mixed monotone property. As a consequence, we particularize our results to the field of metric spaces, partially ordered metric spaces and G-metric spaces, obtaining some very recent results. Finally, we show how to use our main theorems to obtain coupled, tripled, quadrupled and multidimensional coincidence point results.

Results on proximal and generalized weak proximal contractions including the case of iteration-dependent range sets

This paper presents some further results on proximal and asymptotic proximal contractions and on a class of generalized weak proximal contractions in metric spaces. The generalizations are stated for non-self-mappings of the forms for and , or , subject to and , such that converges uniformly to T, and the distances are iteration-dependent, where , , and are non-empty subsets of X, for , where is a metric space, provided that the set-theoretic limit of the sequences of closed sets and exist as and that the countable infinite unions of the closed sets are closed. The convergence of the sequences in the domain and the image sets of the non-self-mapping, as well as the existence and uniqueness of the best proximity points, are also investigated if the metric space is complete. Two application examples are also given, being concerned, respectively, with the solutions through pseudo-inverses of both compatible and incompatible linear algebraic systems and with the parametrical

Improved Mechanical Properties of Compatibilized Polypropylene/Polyamide-12 Blends

Compatibilized blends of polypropylene (PP) and polyamide-12 (PA12) as a second component were obtained by direct injection molding having first added 20% maleic anhydride-modified copolymer (PP-g-MA) to the PP, which produced partially grafted PP (gPP). A nucleating effect of the PA12 took place on the cooling crystallization of the gPP, and a second crystallization peak of the gPP appeared in the PA12-rich blends, indicating changes in the crystalline morphology. There was a slight drop in the PA12 crystallinity of the compatible blends, whereas the crystallinity of the gPP increased significantly in the PA12-rich blends. The overall reduction in the dispersed phase particle size together with the clear increase in ductility when gPP was used instead of PP proved that compatibilization occurred. Young's modulus of the blends showed synergistic behavior. This is proposed to be both due to a change in the crystalline morphology of the blends on the one hand and, on the other, in the PA12-rich blends, to the clear increase in the crystallinity of the gPP phase, which may, in turn, have been responsible for the increase in its continuity and its contribution to the modulus.

Ultrabroad infrared luminescence from Bi-doped aluminogermanate glasses

We report ultrabroad infrared luminescence from Bi-doped aluminogermanate glasses. The infrared luminescence almost covers the whole low loss wavelength region (1200-1650 nm) of silica glass fiber when excited by a diode laser at 980 nm. The full width at half maximum (FWHM) of the luminescence is 510 nm. The luminescence peak can be divided into three Gaussian peaks, and the fluorescence lifetime of the three emissions are 297 mu s, 470 mu s and 1725 mu s, respectively. These fluorescence properties indicate that the glasses are promising material for broadband optical amplifiers. (C) 2007 Elsevier Ltd. All rights reserved.

Coincidence and common fixed point theorems for Suzuki type hybrid contractions and applications

Coincidence and common fixed point theorems for a class of Suzuki hybrid contractions involving two pairs of single-valued and multivalued maps in a metric space are obtained. In addition, the existence of a common solution for a certain class of functional equations arising in a dynamic programming is also discussed.

Fabrication and emission properties of Er3+/Yb3+ codoped tellurite glass fiber for broadband optical amplification

Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A new single mode Er3+/Yb3+ codoped tellurite fiber with D-shape cladding geometry is fabricated in this work. When pumped at 980 nm, a broad erbium amplified spontaneous emission (ASE) nearly 100 nm in the wavelength range of 1450-1650 ran around 1.53 mu m is observed. It was found that the emission spectrum from erbium in tellurite glass fibers is almost twice as broad as the corresponding spectrum in tellurite bulk glass. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of about 2.3 mW from Er3+/Yb3+ codoped tellurite fiber ASE source is obtained under the pump power of 700 mW. The broad 1.53 mu m emission of Er3+ in Er3+/Yb3+ codoped tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers. (c) 2005 Elsevier B.V. All rights reserved.

Modelling and Simulation of ERTMS for Current and Future Mobile Technologies

Nowadays, train control in-lab simulation tools play a crucial role in reducing extensive and expensive on-site railway testing activities. In this paper, we present our contribution in this arena by detailing the internals of our European Railway Train Management System in-lab demonstrator. This demonstrator is built over a general-purpose simulation framework, Riverbed Modeler, previously Opnet Modeler. Our framework models both ERTMS subsystems, the Automatic Train Protection application layer based on movement authority message exchange and the telecommunication subsystem based on GSM-R communication technology. We provide detailed information on our modelling strategy. We also validate our simulation framework with real trace data. To conclude, under current industry migration scenario from GSM-R legacy obsolescence to IP-based heterogeneous technologies, our simulation framework represents a singular tool to railway operators. As an example, we present the assessment of related performance indicators for a specific railway network using a candidate replacement technology, LTE, versus current legacy technology. To the best of our knowledge, there is no similar initiative able to measure the impact of the telecommunication subsystem in the railway network availability.