Software radio: The challenges for reconfigurable terminals

The Software Defined Radio (Sdr) has always been considered as a promising solution for the future of wireless communications because of its ability to provide flexible architecture, enabling multimode and multistandard devices. On the network side, this technology seems to be achievable in a short-term visibility (we even are currently knowing the very beginnings ofSdr solutions in the field of network equipments), but applied to terminals, this technology is likely to reach later its maturity because the embedded issue is synonymous with high constrained architecture. The implementation of software radio terminals requires, for instance, the use of high calculation capability Digital Signal Processors (Dsp) or deeply integrated multiband rf transceiver, whose power consumption quality acts as a brake for the current development of such solutions. Nevertheless, the microelectronic industry will still provide more and more powerful components and, within a few years, theSdr dream will come true for terminal manufacturers. Furthermore, software radio is also a good opportunity to merge computer science and telecommunications technologies, in order to develop smart terminals, which may integrate software components like an operating system or Java virtual machine, etc. Hence, the software radio concept within mobile terminal is still an R&D issue, which requires effort combination in different fields but which also represents a great opportunity for the future of terminals.     

Detection of flowing fluorescent particles in a microcapillary using fluorescence correlation spectroscopy

Capillary flow experiments are described with fluorescent molecules, bacteria, and microspheres using fluorescence correlation spectroscopy as an analytical tool. The flow velocity in the microcapillary is determined by fitting autocorrelation traces with a model containing parameters related to diffusion and flow. The flow profile of pressure-driven flow inside a microcapillary is determined by using the fluorescence fluctuations of a small dye molecule. It was found that bacteria and microspheres are retarded in their flow by optical forces produced by the laser beam.     

Visually induced motion sickness predicted by postural instability

We investigated whether postural instability can predict motion sickness and studied relations among instability, motion sickness, and vection. Nine men and 4 women (mean age = 19.85 years) were exposed, while standing, to an optical simulation of body sway. Head motion was recorded using a magnetic tracking system. Postural instabilities were observed prior to the onset of motion sickness. Vection was reported by most participants, including all who became ill. A discriminant analysis revealed that parameters of postural motion accurately predicted motion sickness. The results confirm that postural instability precedes motion sickness and suggest that measures of postural motion may serve as reliable predictors of motion sickness. Potential applications of this research include the development of on-line diagnostic tools that will allow for the prevention of motion sickness in operational and training settings.     

Silicon etch with chromium ions generated by a filtered or non-filtered cathodic arc discharge

The pre-treatment of substrate surfaces prior to deposition is important for the adhesion of physical vapour deposition coatings. This work investigates Si surfaces after the bombardment by energetic Cr ions which are created in cathodic arc discharges. The effect of the pre-treatment is analysed by X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy and in-depth X-ray photoemission spectroscopy and compared for Cr vapour produced from a filtered and non-filtered cathodic arc discharge. Cr coverage as a function of ion energy was also predicted by TRIDYN Monte Carlo calculations. Discrepancies between measured and simulated values in the transition regime between layer growth and surface removal can be explained by the chemical reactions between Cr ions and the Si substrate or between the substrate surface and the residual gases. Simulations help to find optimum and more stable parameters for specific film and substrate combinations faster than trial-and-error procedure.     

Detecting dynamic patterns in dynamic graphs using subgraph isomorphism

Pattern Analysis and Applications - Graphs have been used in different fields of research for performing structural analysis of various systems. In order to compare the structure of two systems,...     

Analysis of information leakage from encrypted Skype conversations

Voice over IP (VoIP) has experienced a tremendous growth over the last few years and is now widely used among the population and for business purposes. The security of such VoIP systems is often assumed, creating a false sense of privacy. This paper investigates in detail the leakage of information from Skype, a widely used and protected VoIP application. Experiments have shown that isolated phonemes can be classified and given sentences identified. By using the dynamic time warping (DTW) algorithm, frequently used in speech processing, an accuracy of 60% can be reached. The results can be further improved by choosing specific training data and reach an accuracy of 83% under specific conditions. The initial results being speaker dependent, an approach involving the Kalman filter is proposed to extract the kernel of all training signals.     

ALPS – Adaptive Location-based Publish/Subscribe

Location-based publish/subscribe – LPS for short – is an important building block for context-aware applications in mobile ad hoc networks (MANETs). In LPS, published messages are routed based on their content as well as on the location of publishers and subscribers.Existing LPS algorithms can be coarsely classified as follows: (1) message-centric approaches consist in broadcasting published messages, (2) query-centric approaches broadcast subscriber queries for subsequently routing messages, and (3) hybrid approaches broadcast queries and messages each within restricted scopes. Each approach is clearly superior to others for particular communication patterns, e.g., for certain ratios between the number of queries and the number of messages in the network. This paper presents an adaptive location-based publish/subscribe (ALPS) algorithm for settings with multiple, unknown, or varying communication patterns. ALPS can be viewed as a parameterized hybrid LPS algorithm that can seamlessly move between message- and query-centricity based on estimations of the current communication pattern.We evaluate ALPS on two benchmark applications namely in the context of mobile social networking and robot swarms. Our results indicate that ALPS reduces the message complexity by up to a factor 3× compared to the best respective alternative, while performing comparably to the respective optimal solutions with static communication patterns, making ALPS appealing as a one-size-fits-all solution.     

Modeling modeling modeling

Model-driven engineering and model-based approaches have permeated all branches of software engineering to the point that it seems that we are using models, as Molière??s Monsieur Jourdain was using prose, without knowing it. At the heart of modeling, there is a relation that we establish to represent something by something else. In this paper we review various definitions of models and relations between them. Then, we define a canonical set of relations that can be used to express various kinds of representation relations and we propose a graphical concrete syntax to represent these relations. We also define a structural definition for this language in the form of a metamodel and a formal interpretation using Prolog. Hence, this paper is a contribution towards a theory of modeling.     

Influence of a Reactive Element on the Growth of a Thermally Grown Chromia Scale: A Grazing Emission X-ray Fluorescence Study

The oxidation of 55Fe–25Cr–20Ni (wt.%) alloys, with and without added reactive element (RE) Y, were studied using grazing-emission X-ray fluorescence (GEXRF). Samples were studied after isothermal treatments at 750°C in O2 and after cyclic-oxidation treatments. In early-stage oxidation, a Ni-rich scale is formed. The distribution of this early-stage Ni deposit is studied as the scale evolves. The Ni deposit, serving as a marker, remains on the outer scale surface in Y-containing alloys, but is not detectable in scales on Y-free alloys. The results indicate that new chromia scale growth occurs at the outer surface in Y-free alloys but, for Y-containing alloys, new growth occurs away from the outer surface. Thus, a shift in the growth mode is apparently observed at 750°C, consistent with higher-temperature observations. However, unlike the high-temperature measurements, scale-growth rates are not significantly affected by the RE.     

Sources and pathways of nutrients in the semi-arid region of Beijing-Tianjin, China

Semiarid regions worldwide are particularly prone to eutrophication, which causes immense ecological and economic problems. One region that is in transition and requires systematic research for effective intervention is the dry landscape of Beijing-Tianjin (P. R. China). We investigated the sources and spatiotemporal loads of nitrogen and phosphorus species over a one-year period in the Haihe catchment that drains the megacity of Beijing. Although wastewater treatment was improved in recent years, the rivers were heavily contaminated by 0.3-5.3 mg P L(-1) and 3.0-49 mg N L(-1), with toxic levels of nitrite (≥1 mg NO(2)-N L(-1)) and ammonia (≥0.6 mg NH(3)-N L(-1)). The average NH(4)(+) (16.9 mg N L(-1)) increased by 160% compared to 1996-levels. Mass fluxes and δ(15)N-signatures revealed that nutrients originated almost exclusively from sewage. Furthermore, the water balance demonstrated that >90% of the polluted river water was diverted for irrigation, thereby threatening food safety and groundwater quality. Per capita loads of 1.42 kg N/yr and 115 g P/yr were comparable to the peak discharges typical of Europe and the United States in 1970-1990, but concentrations were 2-3 times higher in the Beijing-Tianjin region. Our research identified sewage as the predominant nutrient source in this semiarid region, which suggests that state-of-the-art wastewater treatment would drastically mitigate eutrophication and even more rapidly than was previously observed in Europe.