Handover management based on user’s mobility specification

Considering the highly dynamic nature of wireless networks, the major challenge in this environment is the provision of QoS guarantees that different applications demand. Recent research is interested in advance resource reservation to provide the necessary QoS to the mobile terminals. Another way to obtain a better use of the resources in this environment is to determine the future locations of the mobile terminal. This paper describes a user’s mobility profile management based approach for advance resource reservation in wireless networks; it is based on theNsis signaling. This reservation is based on an objectMspec (Mobility Specification) which determines the future location of the mobile terminal. The mspec object is a part of a user’s mobility profile; this last is determined by the mobile terminal. Another applicability of our user’s mobility profile is in the 4G wireless systems, in this case; the mobile terminal supports various access technologies and the user’s mobility profile is used to adapt the vertical and the diagonal handover to the user’s needs.     

High-voltage LDMOS transistors fully compatible with a deep-submicron 0.35 μm CMOS process

This work presents the design of LDMOS transistors fully compatible with a standard CMOS process, only requiring mask layout manipulation. A conventional 0.35 μm CMOS process was elected to demonstrate the viability of the approach. The prototyped LDMOS transistor exhibits a breakdown voltage of 24 V, which represents an improvement of 31% when compared with the high-voltage extended-drain NMOS available in the process library, while other static parameters remain in the same range. Furthermore, this solution enables the CMOS integration of a high-voltage pass-transistor, as a consequence of the formation of an isolated lightly doped p-type region inside the n-well.     

Nanoelectronic SET-based core for network-on-chip architectures

Nanoelectronics is a very promising step the world of electronics is taking. It is proved to be more efficient than the microelectronic approaches currently in use, mainly in terms of area and energy management. A Single-Electron Transistor (SET) is capable of confining electrons to sufficiently small dimensions, so that the quantization of both their charge and their energy is easily observable, making the SET's quantum mechanical devices. These features should allow building chips with a number of devices orders of magnitude greater than indicated by the roadmap still respecting area and power consumption restrictions. In this sense, Tera Scale Integrated (TSI) systems can be feasible in the future. A digital module, such as an arithmetic logic unit, completely implemented with SETs has already been proposed and validated by simulation. In this work a completely SET based network-on-chip (NoC) nanoelectronic core is proposed. Furthermore, a simple NoC architecture based on that nanoelectronic core is also evaluated. It is shown that the SET-based NoC has a promising performance considering parameters such as power consumption, area and clock frequency. A simple comparison of mesh NoC chip prototypes is shown.     

A New Hand-Held Microsystem Architecture for Biological Analysis

This paper presents a hand-held microsystem based on new fully integrated magnetoresistive biochips for biomolecular recognition (DNA hybridization, antibody antigen interaction, etc.). Magnetoresistive chip surfaces are chemically treated, enabling the immobilization of probe biomolecules such as DNA or antibodies. Fluid handling is also integrated in the biochip. The proposed microsystem not only integrates the biochip, which is an array of 16times16 magnetoresistive sensors, but it also provides all the electronic circuitry for addressing and reading out each transducer. The proposed architecture and circuits were specifically designed for achieving a compact, programmable and portable microsystem. The microsystem also integrates a hand-held analyzer connected through a wireless channel. A prototype of the system was already developed and detection of magnetic nanoparticles was obtained. This indicates that the system may be used for magnetic label based bioassays     

Local electronic structure,optical bandgap and photoluminescence (PL) properties of Ba(Zr0.75Ti0.25)O3 powders

Ba(Zr_0.75Ti_0.25)O₃ (BZT-75/25) powders were synthesized by the polymeric precursor method. Samples were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) techniques. Their electronic structures were evaluated by first-principle quantum mechanical calculations based on density functional theory at the B3LYP level. Their optical properties were investigated by ultraviolet-visible (UV-Vis) spectroscopy and photoluminescence (PL) measurements at room temperature. XRD patterns and Rietveld refinement data indicate that the samples have a cubic structure. XANES spectra confirm the presence of pyramidal [TiO₅] clusters and octahedral [TiO₆] clusters in the disordered BZT-75/25 powders. EXAFS spectra indicate distortion of Ti–O and Ti–O–Ti bonds the first and second coordination shells, respectively. UV-Vis absorption spectra confirm the presence of different optical bandgap values and the band structure indicates an indirect bandgap for this material. The density of states demonstrates that intermediate energy levels occur between the valence band (VB) and the conduction band (CB). These electronic levels are due to the predominance of 4d orbitals of Zr atoms in relation to 3d orbitals of Ti atoms in the CB, while the VB is dominated by 2p orbitals related to O atoms. There was good correlation between the experimental and theoretical optical bandgap values. When excited at 482 nm at room temperature, BZT-75/25 powder treated at 500 °C for 2 h exhibited broad and intense PL emission with a maximum at 578 nm in the yellow region.     

A Single-Stage High-Power-Factor Electronic Ballast Based on Integrated Buck Flyback Converter to Supply Metal Halide Lamps

In this paper, a novel single-stage electronic ballast with a high power factor is presented. The ballast circuit is based on the integration of a buck converter to provide the power factor correction, and a flyback converter to control the lamp power and to supply the lamp with a low-frequency square-waveform current. Both converters work in discontinuous conduction mode, which simplifies the control. In spite of being an integrated topology, the circuit does not present additional stress of voltage or current in the main switch, which handles only the flyback or buck current, depending on the operation mode. To supply the lamp with a low-frequency square-wave current to avoid acoustic resonances, the flyback has two secondary windings that operate complementarily at a low frequency. The design procedure of the converters is also detailed. Experimental results from a 35-W metal halide lamp are presented, where the proposed ballast reached a power factor of 0.95, a total harmonic distortion of 30% (complying with IEC 61000-3-2), and an efficiency of 90%.     

FIR Laser Lines from CH3OD: A Review

The methanol isotopic species CH₃OD has also proved to be an efficient and powerful medium to generate radiation in the far infrared (FIR) region. After the critical review of 1994, six papers have been published dealing with new FIR laser lines from this molecule. As a consequence of the use of wide tunability waveguide CO₂ lasers as well as a new pulsed CO₂ laser operating at hot and sequential bands, as of optical pumping sources, the total number of the FIR laser lines increased from 122 in 1994 to 227 today. In this communication we present an updated and complete catalogue of FIR laser lines generated from CH₃OD. Information on wavelength, offset, relative polarization, intensity, and optimum operation pressure is generally available.     

MCT technology challenges for mass production

Second generation infrared (IR) detectors are now mature at the production level. These detectors are mostly based on HgCdTe (MCT) materials technology. The main second generation detectors at the mass production level are the 288 4 long wave length for most of the European forward-looking infrared (FLIR) and the 480 6 long wave length for the U.S. Army SADA applications. As far as the 288 4 is concerned, SOFRADIR has delivered more than 3000 units already and the market is estimated to be 15,000 units at least! The market is also very large for SADA II units and SOFRADIR has produced them since the end of 1999. Thus, SOFRADIR produces large quantities of mercury cadmium telluride (MCT) detectors and has a unique experience for MCT detectors in mass production. MCT materials technology challenges for mass production concern the main following issues: Quality and reproducibility, MCT wafer size increase, array yield level increase, and the collective manufacturing approach. These issues are discussed in detail in this paper as well as future trends.     

Exploring Social Networks and Improving Hypertext Results for Cloud Solutions

Internet technologies are constantly evolving as well as the way people use them. Search engines help users to find higher and better relevant results to their searches. Cloud Computing is an evolution of the Internet services and provides a step further ecosystem that can be used to improve the search of more relevant results. Each search engine is based on different modules in order to retrieve the results expected by users using specific keywords. Social networks appear as a reliable Web technology that can directly support a content search. Several studies have been performed showing the growth of social networks in people lives. Using the cloud computing paradigm it is possible to propose a more scalable and efficient way to explore public information available on online social networks. This paper includes the analyses of several social networks services, available contents, cloud-crawlers, and information extraction. In order to collect relevant data from social networks, a social crawler on cloud is proposed. The new approach provides a cloud-based crawler for low-cost, effective, and personalized search models. Moreover, a new algorithm to rank Web documents is proposed and demonstrated. The proposed system is evaluated in comparison with the top Internet search engine, Google, its behavior is very promising, and it is ready for use.     

Analysis of the selective behavior of multilayer structures with adielectric grating

The potential use as dichroic surfaces in the millimeter frequency band of multilayer dielectric structures with a grating in one of the layers is examined. It is shown that the selectivity of the structure may be increased by using a convenient array of dielectric sections in the characteristic cell of the periodic layer. It is also shown how the selective behavior of the structure depends on the angle of incidence of the wave that excites the structure and on the height-periodicity ratio of the periodic layer. In addition, for an unloaded periodic layer, an approximate procedure is described to predict how many times and at which frequencies maximum reflection occurs. The effect of loading the periodic layer with increasing number of dielectric layers is examined with the conclusion that the number of frequencies where maximum reflection occurs may be increased