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61.
Ilias Chlis Domenico Pepe Domenico Zito 《International Journal of Circuit Theory and Applications》2016,44(9):1697-1705
This paper reports a phase noise analysis in a differential Armstrong oscillator circuit topology in CMOS technology. The analytical expressions of phase noise due to flicker and thermal noise sources are derived and validated by the results obtained through SpectreRF simulations for oscillation frequencies of 1, 10, and 100 GHz. The analysis captures well the phase noise of the oscillator topology and shows the impact of flicker noise contribution as the major effect leading to phase noise degradation in nano‐scale CMOS LC oscillators. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
62.
The problem of the non-causal inversion of linear multivariable discrete-time systems is analyzed in the geometric approach framework and is solved through the computation of convolution profiles which guarantee perfect tracking under the assumption of infinite-length preaction and postaction time intervals. It is shown how the shape of the convolution profiles is related to both the relative degree and the invariant zeros of the plant. A computational setting for the convolution profiles is derived by means of the standard geometric approach tools. Feasibility constraints are also taken into account. A possible implementation scheme, based on a finite impulse response system acting on a stabilized control loop, is provided. 相似文献
63.
Pietro Russo Giorgio Simeoli Domenico Acierno Valentina Lopresto 《Polymer Composites》2015,36(11):2022-2029
Polyolefin‐based composite laminates reinforced with jute fabric were prepared by compression molding and investigated in terms of flexural properties and impact behavior. The use of a virgin polypropylene as the matrix was compared with two polyolefin matrices coming from discarded car bumpers and selected packaging wastes, respectively, and mainly constituted by mixtures of polyethylene and polypropylene resins. The influence of a coupling agent (maleated polypropylene) was always considered in order to improve the interfacial adhesion and, consequently, the composite strength. The effect of this coupling agent, clearly dependent on the amount of polypropylene phase in the overall mixture, was found to be satisfactory only in the case of virgin polypropylene‐based systems. These latter, in presence of maleated polypropylene, have shown higher flexural parameters, lower propagation energy and higher breaking impact load with respect to uncompatibilized ones. Results were supported by morphological observations of impact surfaces, always highlighting a poor adhesion at the reinforcement–matrix interface except in compatibilized virgin polypropylene‐based laminates. POLYM. COMPOS., 36:2022–2029, 2015. © 2014 Society of Plastics Engineer 相似文献
64.
A super-peer model for resource discovery services in large-scale Grids 总被引:12,自引:0,他引:12
Carlo Mastroianni Domenico Talia Oreste Verta 《Future Generation Computer Systems》2005,21(8):440-1248
As deployed Grids increase from tens to thousands of nodes, peer-to-peer (P2P) techniques and protocols can be used to implement scalable services and applications. The super-peer model is a novel approach that helps the convergence of P2P models and Grid environments and can be used to deploy a P2P information service in Grids. A super-peer serves a single physical organization in a Grid, and manages metadata associated to the resources provided by the nodes of that organization. Super-peers connect to each other to form a peer network at a higher level. This paper examines how the super-peer model can handle membership management and resource discovery services in a multi-organizational Grid. A simulation analysis evaluates the performance of a resource discovery protocol; simulation results can be used to tune protocol parameters in order to increase search efficiency. 相似文献
65.
Laurà R Magnoli D Zichichi R Guerrera MC De Carlos F Suárez AÁ Abbate F Ciriaco E Vega JA Germanà A 《Microscopy research and technique》2012,75(3):359-366
The zebrafish pineal gland plays a fundamental role in the regulation of the circadian rhythm through the melatonin secretion. The pinealocytes, also called photoreceptive cells, are considered the morphofunctional unit of pineal gland. In literature, the anatomical features, the cellular characteristics, and the pinealocytes morphology of zebrafish pineal gland have not been previously described in detail. Therefore, this study was undertaken to analyze the structure and ultrastructure, as well as the immunohistochemical profile of the zebrafish pineal gland with particular reference to the pinealocytes. Here, we demonstrated, using RT-PCR, immunohistochemistry and transmission electron microscopy, the expression of the mRNA for rhodopsin in the pineal gland of zebrafish, as well as its cellular localization exclusively in the pinealocytes of adult zebrafish. Moreover, the ultrastructural observations demonstrated that the pinealocytes were constituted by an outer segment with numerous lamellar membranes, an inner segment with many mitochondria, and a basal pole with the synapses. Our results taken together demonstrated a central role of zebrafish pinealocytes in the control of pineal gland functions. 相似文献
66.
The paper presents a neural network model of the touch sensitivity circuit of the nematode Caenorhabditis elegans. We describe a serie of simulations in which neural networks are trained, using a genetic algorithm, to reproduce the habituation of the nematode's touch sensitive behavior. A lesion study of the network allows to make a direct comparison between the fine functioning of the model and the data collected in real organisms. The model accords well with the known neurobiological data and it suggests some hypotheses about the functioning of the neural circuit and of single neurons. 相似文献
67.
Rishi Raj Luca Pederiva Masaki Narisawa Gian Domenico Soraru 《Journal of the American Ceramic Society》2019,102(3):924-929
Silicon-based polymers evolve into refractory ceramics when heated gradually up to ~1000°C. The conversion is accompanied by the loss of gaseous species, and by a two-fold increase in density. The shrinkage can produce microcracks if the heating rate is too high, or if the specimen is too thick. This communication builds on earlier work whereby the measurement of gas evolution, and its relationship with viscous flow, are related to the onset of fracture in disk-shaped green (polymer) samples. The onset is determined as a function of the thickness of the disks, and of the heating rate. The results are presented in the form of a processing map. The overlay with gas evolution, and strain-rate measurements, suggest that fracture initiates with the release of hydrogen and methane, starting at temperatures near 750°C. 相似文献
68.
Gian Domenico Sorarù Lakshminath Kundanati Balanand Santhosh Nicola Pugno 《Journal of the American Ceramic Society》2019,102(3):907-913
Silicon oxycarbide (SiOC) glasses in the form of thin, dense, and crack-free samples were fabricated according to the polymer pyrolysis route starting from cross-linked polysiloxane. The amount of free carbon in the final SiOC materials was varied in the range 18-60 vol%. The mechanical properties of the SiOC glasses were measured by nanoindentaion technique and revealed that both the Young's modulus and the hardness decrease with increase in the free carbon content and follow a simple rule of mixtures model. 相似文献
69.
Francesco Basile Pasquale Chiacchio Domenico Del Grosso 《Control Engineering Practice》2012,20(12):1426-1437
Nowadays the low cost of wireless communications allows the real time monitoring of the state of manual-pick warehouse systems making possible the real time control of these systems. At this aim, an approach based on a two-level model is presented in this paper. At the lower level, Petri nets are used to build online a model representing the active missions state and to detect conflicts among resources. At the upper level, logical expressions are used to add constraints for a single mission or item. The model is proved to be effective for online monitoring, scheduling and rescheduling of warehouse activities. 相似文献
70.
Pasquale De Meo Giovanni Quattrone Domenico Ursino 《User Modeling and User-Adapted Interaction》2010,20(1):41-86
In this paper we propose a query expansion and user profile enrichment approach to improve the performance of recommender
systems operating on a folksonomy, storing and classifying the tags used to label a set of available resources. Our approach
builds and maintains a profile for each user. When he submits a query (consisting of a set of tags) on this folksonomy to
retrieve a set of resources of his interest, it automatically finds further “authoritative” tags to enrich his query and proposes
them to him. All “authoritative” tags considered interesting by the user are exploited to refine his query and, along with
those tags directly specified by him, are stored in his profile in such a way to enrich it. The expansion of user queries
and the enrichment of user profiles allow any content-based recommender system operating on the folksonomy to retrieve and
suggest a high number of resources matching with user needs and desires. Moreover, enriched user profiles can guide any collaborative
filtering recommender system to proactively discover and suggest to a user many resources relevant to him, even if he has
not explicitly searched for them. 相似文献