This paper describes the Multimedia Educational Pills (MEPs) model. MEPs are highly concentrated courses, designed to address a topic through multiple representations, following a recursive, ...non-cumulative, logic, as pointed out by the Cognitive Flexibility Theory (CFT) methodology. MEPs have been designed to meet the educational challenges posed by the transition from an industrial to an information age. They focus on promoting the capacity to deal with uncertainties and solve problems in an adaptive way. Variety is the key to the architecture and the main benefit of applying MEPS. In fact, MEPS are made up of multiple resources. Each learning object has its own particular shape, perspective and conceptual dimension. In addition, the MEPS are designed to be used in multiple ways, such as e-learning, classroom, blended learning, and to be accessible on multiple devices. MEPs can support multiple teaching strategies (such as self-training, cooperative learning) and multiple learning architectures. In particular MEPs - used before or as follow-up -- can integrate and improve traditional classrooms. Finally MEPs can be used in support of coaching paths or in support of outdoor training paths.
In this paper, we analyze the performance of a particular class of Transmitted-Reference (TR) receiver for Impulse Radio (IR) Ultra Wide Band (UWB) communication systems, which is called Chip-Time ...Differential Transmitted- Reference (T C -DTR). The analysis aims at investigating the performance of this receiver in the presence of faded narrow- band interference, and at comparing it with other TR receiver schemes proposed in the literature. It is shown that T c -DTR receivers can offer a substantial performance gain with respect to other non-coherent receiver architectures, provided that some optimization conditions on code design are satisfied. Guidelines for optimal code and system optimization to reject narrow-band interference are provided in the present manuscript, as well as their effect on system performance. Numerical simulations are also shown to substantiate findings and analytical derivations.
Article Renzo, M Di; Feninat, F El; Jiménez-Esquivel, B ...
Canadian journal of chemistry,
11/1998, Letnik:
76, Številka:
11
Journal Article
Recenzirano
Human dentin consists of protein and mineral phases in the form of a collagen network reinforced with apatite. The bonding of materials to dentin, an important goal of dental materials research, can ...be achieved by the reaction of adhesion promoters with either of these phases. Our group is concerned with such bonding, and has used surface-sensitive instrumentation to elucidate the nature of a variety of surface treatments of dentin. Here, we discuss some of our findings, with particular emphasis on the kinetics of surface demineralization and deproteination, the reaction of formaldehyde with collagen, and the reaction of organophosphate with dentin apatite. The ramifications of our findings will be examined.Key words: dentin, adhesion, vibrational spectroscopy, atomic force microscopy.
How very massive stars form is still an open question in astrophysics. VFTS682 is among the most massive stars known, with an inferred initial mass of \(\sim\)150 \(M_\odot\) . It is located in 30 ...Doradus at a projected distance of 29 pc from the central cluster R136. Its apparent isolation led to two hypotheses: either it formed in relative isolation or it was ejected dynamically from the cluster. We investigate the kinematics of VFTS682 as obtained by Gaia and Hubble Space Telescope astrometry. We derive a projected velocity relative to the cluster of \(38 \pm 17 \mathrm{km \ s^{-1}}\) (1\(\sigma\) confidence interval). Although the error bars are substantial, two independent measures suggest that VFTS682 is a runaway ejected from the central cluster. This hypothesis is further supported by a variety of circumstantial clues. The central cluster is known to harbor other stars more massive than 150 \(M_\odot\) of similar spectral type and recent astrometric studies on VFTS16 and VFTS72 provide direct evidence that the cluster can eject some of its most massive members, in agreement with theoretical predictions. If future data confirm the runaway nature, this would make VFTS682 the most massive runaway star known to date.
Twenty-five male patients with superficial bladder cancer underwent intravesical Bacillus Calmette Guerin immunotherapy. A high incidence of side effects has occurred using three different substrains ...of BCG. Our interest has been focused on BCG related granulomatous prostatitis: we have found four asymptomatic patients with histologically diagnosed disease. We suppose therefore that its incidence is underestimated.
In this paper, we offer a simple but general framework for analyzing the statistical properties of mobile-to-mobile (M2M) fading channels. Differently from other contributions that can be found in ...the literature, we are interested in end-to-end performance metrics rather than in simply analyzing the statistical behavior of the so-called product channel. As a consequence, our proposed framework is suited for system-level performance analysis of channel dynamics in multi-hop wireless networks. In particular, we report a general framework for computing the spatial auto-correlation function of the end-to-end Signal-to-Noise Ratio (SNR) over Log-Normal shadow-fading channels. The accuracy of the proposed approach is also substantiated via Monte Carlo simulations.
In two recent contributions, we have provided a comparative analysis of various optimization algorithms, which can be used for atomic location estimation, and suggested an enhanced version of the ...Steepest Descent (ESD) algorithm, which we have shown to be competitive with other distributed localization algorithms in terms of estimation accuracy and numerical complexity. Moreover, therein we have conducted a preliminary statistical characterization of the positioning error distribution, by showing that it can be well approximated by the family of Pearson distributions, as well as pointed out that its knowledge may be efficiently used to speed-up the analysis of iterative-based positioning algorithms by avoiding the need of simulating the whole location discovery algorithm, and allowing simulation at the atomic level only. In this contribution, based on the preliminary results shown in, we propose a comprehensive statistical analysis of the positioning error distribution for the ESD algorithm, by providing the parameters of the Pearson fitting distribution with respect to two important design factors for wireless sensor networks (WSNs): i) the ranging error standard deviation, which represents the input parameter for every localization algorithm, and ii) the geometric dilution of precision factor, which provides a simple parameter to account for different network topologies. In particular, we report an extensive number of simulation results that may provide important insights to the system designer: i) allow a parametric analysis to figure out the joint effect of ranging errors and network topology on the performance of the localization algorithms, and ii) give a general framework for modeling the statistics of the positioning error, which may be used for network planning, as well as for the analysis and design of the upper layers of the protocol stack.
In this paper, we analyze the performance of a simple receiver architecture for impulse radio (IR) ultra wide band (UWB) systems. The receiver makes use of a differential binary phase shift keying ...(DBPSK) modulation, and a differential rake (D-Rake) receiver that does not require channel estimation. The performance study is conducted by considering the recently standardized IEEE 802.15.4 a channel model, as well as narrow-band interference (NBI) co-located in the same transmission band of the UWB signal. The analysis will be performed with and without frequency and timing synchronization errors, in order to identify the design constraints of the synchronization unit to guarantee the proper operation of the receiver over realistic propagation environments. The results will show that (i) NBI can significantly worsens the performance of the receiver, (ii) the maximum tolerable frequency offset should be less than 10 KHz for a UWB signal with center frequency equal to 4.5 GHz, and (iii) the maximum tolerable timing offset should be much less than 4.2 ns for a pulse with width of 10 ns (500 MHz of transmission bandwidth at -10 dB with respect to the spectrum peak) and a chip time with duration of 85.3 ns.
In a recent contribution 1, we have provided a comparative analysis of various optimization algorithms, which can be used for atomic location estimation, and suggested an enhanced version of the ...steepest descent (ESD) algorithm, which we have shown (with preliminary results) to be competitive with some other distributed localization algorithms in terms of estimation accuracy and numerical complexity. Moreover, we have conducted a statistical characterization of the position error distribution, by showing that it can be well approximated by the family of Pearson distributions. In this contribution, we first analyze with further detail the proposed ESD algorithm, and then show that the knowledge of the position error distribution may be efficiently used to speed-up the analysis of iterative-based positioning algorithms by avoiding the need of simulating the whole location discovery algorithm, and allowing simulation at the atomic level only. In particular, we will report some numerical results showing that the two approaches i) running the whole positioning algorithm when having at its input ranging errors, and ii) running the localization algorithm at the atomic level when having at its input ranging and positioning errors, provide the same results, with the latter approach having the additional positive feature to be simpler to be implemented. The proposed strategy may be efficiently used for analysis and optimization of various network settings.
PDF
