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2.
Morosi S. Marabissi D. Enrico Del Re Fantacci R. Del Santo N. 《Power Delivery, IEEE Transactions on》2006,21(4):1892-1897
This paper deals with a variable rate discrete multitone modulation system for broadband power-line communications, based on the bit-loading algorithm proposed by Leke and Cioffi. In the proposed system a suitable least mean square channel estimator is considered, which is based on the insertion of a training sequence (TS). The proposed approach will be compared with the ideal channel estimates, showing its effectiveness. Moreover, different TS lengths will be compared. The system performance, expressed in terms of bit rate and bit-error rate, is derived by simulation with and without estimation errors. The propagation environment has been assumed as a frequency-selective multipath fading channel with additive colored Gaussian noise, according to the in-building networks model. 相似文献
3.
Jones Enrico E.; Ghannam Jess; Nigg Joel T.; Dyer Jennifer F. 《Canadian Metallurgical Quarterly》1993,61(3):381
Articulates a paradigm for single-case research in psychotherapy. A patient diagnosed as having major depressive disorder was seen in an intensive, twice-weekly psychodynamic psychotherapy for 2.5 years. Each session was videotaped, and assessments of patient change were obtained at regular intervals. A time-series analysis was used to model fluctuations in the therapy process to take into account time and the effect of previous events on subsequent changes, thereby preserving the context-determined meaning for therapist and patient actions. A bidirectional analysis of causal effects shows that the influence processes between therapist and patient are mutual and reciprocal and suggests that the effect of the patient on the therapist and on the process has not been made sufficiently explicit in previous models of process and change. The potential of intensive single-case designs for uncovering causal effects in psychotherapy is demonstrated. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Giovanni Giambene Enrico Zoli 《International Journal of Satellite Communications and Networking》2003,21(2):199-225
In this paper, we investigate a packet access scheme that is able to support mixed traffics in the presence of high propagation delays. Referring to a Time‐Code Division Multiple Access air interface, we propose a Medium Access Control (MAC) protocol based on a random access scheme. A successful attempt grants the use of a slot‐code resource. This protocol is named Adaptive Time Code‐Packet Reservation Multiple Access (ATC‐PRMA), since the access parameters are changed, depending on the traffic load conditions, so as to fulfil Quality of Service requirements. Numerical examples are carried out for the Low Earth Orbit (LEO)‐Mobile Satellite System (MSS) scenario, but all these considerations could be applied to High‐Altitude Platform Stations (HAPSs) as well. In both cases, high propagation delays prevent an immediate feedback to users. An analytical approach is proposed to study the stability of our MAC scheme. Accordingly, we define a criterion for optimizing system performance. The predicted ATC‐PRMA behaviour is supported by simulation results. Finally, we show the performance improvement of ATC‐PRMA with respect to a MAC protocol not employing adaptive parameters. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
Enrico Tronci 《International Journal on Software Tools for Technology Transfer (STTT)》2006,8(4-5):355-358
In today’s competitive market designing of digital systems (hardware as well as software) faces tremendous challenges. In
fact, notwithstanding an ever decreasing project budget, time to market and product lifetime, designers are faced with an
ever increasing system complexity and customer expected quality. The above situation calls for better and better formal verification
techniques at all steps of the design flow. This special issue is devoted to publishing revised versions of contributions
first presented at the 12th Advanced Research Working Conference on Correct Hardware Design and Verification Methods (CHARME) held 21–24 October 2003 in L’Aquila, Italy. Authors of well regarded papers from CHARME’03 were invited to submit
to this special issue. All papers included here have been suitably extended and have undergone an independent round of reviewing. 相似文献
6.
Enrico Saggese Giuseppe Chiassarini 《International Journal of Satellite Communications and Networking》1989,7(4):295-306
One key technology, for the implementation of future on-board processing payloads, is the multicarrier demodulator (MCD). The MCD is instrumental in allowing FDMA/TDM access schemes which optimize the use of on-board and ground resources in VSAT networks. This paper deals with the analogue and digital implementations of MCD, trying to assess the fields of application of each of the two technologies. 相似文献
7.
The addition reactions of ethylene oxide and/or propylene oxide catalyzed by KOH and initiated with compounds containing free hydroxyls are followed by secondary reactions which vary the expected molecular weight. By using ethylene oxide, diols are formed and by using propylene oxide, both diols and unsaturated monofunctional compounds are formed. These products are usually characterized by their hydroxyl number. The average molecular weight is found by taking into consideration the starter functionality only. There are often some behavioral differences among similar products owing to the different quantity and chain length of the secondary products contained therein. The secondary products are analyzed and the quantity of the secondary products were determined from the hydroxyl number values and from the unsaturation of reagents and products. In the case of monofunctional adducts using the calculation method, the results have been experimentally confirmed. 相似文献
8.
An experimental study was carried out on the ultrafiltration (UF) of protein-containing solutions under different conditions, as compared with a solution of a linear synthetic polymer. Three different fluidynamic regimes were investigated, namely, unstirred batch system, stirred batch system, and recirculating system. The results obtained substantially agree with the predictions of the gel polarization model. A significant effect of the electrolytes on the UF flux has been observed, which can be attributed to solute–solute interaction. The influence of different UF membranes has also been investigated. 相似文献
9.
The thermodynamic properties of polymer solutions are frequently described in terms of the Flory-Huggins equation. This equation includes a parameter χ, which depends upon the intermolecular forces acting between the molecules in a solution. The experimental determination of χ was performed by an improved microtechnique and extended to a wide range of polar and nonpolar diluents of polyethylene. Careful correlations are prescribed for calculating χ from pure-component properties; they are based on an extension of the Hildebrand-Scatchard theory of solutions and on the theory of intermolecular forces. Polar (τ) and nonpolar (δ) solubility parameters are presented for a variety of solvents. For polyethylene—nonpolar solvent systems we have emphasized the factor deciding the sign of heat of mixing, while for polyethylene-polar solvent systems we have determined the contribution of dipole-induced dipole interactions ψ (δτ) in interchange-energy density B and, hence, χ. 相似文献
10.
Nico Pietroni Davide Tonelli Enrico Puppo Maurizio Froli Roberto Scopigno Paolo Cignoni 《Computer Graphics Forum》2015,34(2):627-641
We introduce a framework for the generation of polygonal gridshell architectural structures, whose topology is designed in order to excel in static performances. We start from the analysis of stress on the input surface and we use the resulting tensor field to induce an anisotropic nonEuclidean metric over it. This metric is derived by studying the relation between the stress tensor over a continuous shell and the optimal shape of polygons in a corresponding gridshell. Polygonal meshes with uniform density and isotropic cells under this metric exhibit variable density and anisotropy in Euclidean space, thus achieving a better distribution of the strain energy over their elements. Meshes are further optimized taking into account symmetry and regularity of cells to improve aesthetics. We experiment with quad meshes and hexdominant meshes, demonstrating that our gridshells achieve better static performances than stateoftheart gridshells. 相似文献