bluuebunny/crossref_metadata_2025_split huggingface dataset:
An example of a new VLSI design style based on systolic macrocells: A high‐speed single‐chip transversal filter for signal processing applications
Authors: Roncella Roberto , Saletti Roberto , Terreni Pierangelo 
Published: September 2008

AbstractThis paper describes the VLSI design of a high‐speed single‐chip FIR filter for data with a limited number of bits. A new design style that allows easy design of high speed VLSI systems was used. This style is based on the extensive use of systolic arrays and it is well suited to VLSI system realizations for digital signal processing (DSP) applications. This realization shows that high performance systems can be obtained with a systolic approach, using a few main building blocks called macrocells, systolic at the bit‐level, of general use and easily interconnected.
A new ARQ scheme using a go‐back‐N protocol
Authors: Benelli Giuliano 
Published: September 2008

AbstractIn this paper a new protocol suitable for communication systems using error detecting codes is described. This scheme is similar to a Go‐Back‐N protocol, but it presents higher performance. The throughput of the protocol is determined through a theoretical analysis. The results show that the proposed protocol maintains, as the Go‐Back‐N schemes, a simple implementation structure, but at the same time permits to achieve high throughput values. In particular, for high error rates in the communication channel the described protocol achieves performance comparable with that of the selective protocol with infinite buffer.
A unified analysis for the multiple‐site diversity outage performance of single/dual ‐ polarized communication systems
Authors: Kanellopoulos John , Ventouras Spyros 
Published: September 2008

AbstractMultiple site diversity systems are foreseen for earth to satellite paths operating at frequencies above 10 GHz in localities with high rain‐induced attenuation. A recently suggested model for the prediction of diversity performance is properly modified to include also the double polarized systems. The unified method for single/double polarized earth‐space paths uses the assumption of lognormal unconditional distribution of rainfall for the location under consideration. Numerical results are presented corresponding to several operating systems under the hypothesis of using both single and double polarization. Some useful conclusions are deduced.
New technologies for physically disabled individuals
Authors: Tronconi Alberto , Billi Marco 
Published: September 2008

AbstractOften, physical impairments due to congenital conditions, acquired disabilities, progressive neurological diseases, and temporary conditions, do not allow the processes by which information is exchanged between people through verbal and non‐verbal behaviours. Furthermore some physically handicapped, encounter insurmountable obstacles with computer access. These impediments also prevent many possibilities in the use of electronic communication systems.In this paper we present some notes on the use of the new technology to realize communication aids for physically disabled persons. We supply some information on the devices which are commercially available and on the systems that we are developing.
Multimedia services and applications
Authors: Barbosa Luis Orozco , Georganas Nicolas D. 
Published: September 2008

AbstractMultimedia communications is the field referring to the representation, storage, retrieval and dissemination of machine‐processable information expressed in multiple media, such as text, voice, graphics, image, audio and video. With the advent of high capacity storage devices powerful and yet economical computer workstations and high‐speed integrated services digital networks providing a variety of multimedia communications services are becoming not only technically but also economically feasible. Applications in medicine, education, travel, real‐estate, banking, insurance, administration and publishing and advertising are emerging at a fast pace. These applications are characterized by large multimedia documents that have to be communicated within very short delays. Computer‐controlled cooperative work, whereby a group of users can jointly view, create, edit and discuss multimedia documents is going to be characteristic of many transactions in the year 2000. In this paper, we review the activity in Multimedia Communications, Services and Applications.
Evolution of LANs and MANs towards high speeds: Gigabits per second and beyond
Authors: Gerla Mario , Fratta Luigi , Bannister Joseph 
Published: September 2008

AbstractThis paper traces the evolution of LANs ad MANs from the early Ethernet days to recent Gigabit per second prototypes. Three generation are identified. The first generation includes Ethernets, Token Rings and Token Busses, and has a speed upper limit in the order of lOMbit/s. The second generation consists of architectures which have evolved from the first generation exploiting the fiber optics technology and properly modifying the access protocols. Higher speeds (in the order of hundreds of Mbit/s) and larger distances are thus achieved. Typical examples are FDDI and DQDB. The third generation represents a further step in the direction of higher speeds (hundreds of Gigabit per second). The key elements to achieve such high speeds are passive optic components and wavelength division.The paper consists of two parts. In the first part, the evolution of topologies and access protocols from generation to generation is described. In the second part, two representative examples of third generation networks, namely, Tree Net and WON, are presented.
Structure of broadband communication network
Authors: Mossotto Cesare 
Published: September 2008

AbstractThe present telecommunication evolution is driven by a very complex relationship between market forces and new advanced technologies. This process is accelerated, among other things, by regulation actions and, more important, by the availability for end users of competing alternative solutions. Aim of the paper is first to discuss some of the major requirements/opportunities ‐ from standard to business user needs, from intelligence to decentralization, from mobile to image communications. This allows setting a rationale and an overall consistent framework for the three‐yearSubproject 1: Structure of Broadband Communication Network.After a brief introduction about the innovation process in complex systems, the paper clarifies the role and the time scale for the service offering of broadband structures in telecommunication networks. The main research topics are then summarized thereby giving an introduction to the three more focused Conference papers, which consider specific relevant issues, broadband network evolution, metropolitan area networks, and satellite systems for high‐definition television (HDTV). Finally, the subproject organization, work progress and major achievements obtained in the first‐year activity are outlined.
Technologies for broadband optical communications
Authors: Daino Benedetto 
Published: September 2008

AbstractIn the Research Project on Telecommunications of the National Research Council, the area of the «Technologies for broadband optical communications» was individuated as one of the key areas for the promotion of advanced research activities and the formation of highly specialized competences in a field which will be determinant for the development of future communication networks. The subproject 2 was established on this view, and a detailed plan for researches on some relevant topics, namely the coherent techniques, the optical switching and the optoelectronic components, has been defined. In the following, the objectives and the research activities included in the project are illustrated in detail.
Experimental realizations of broadband communication networks
Authors: Cappellini Vito 
Published: September 2008

AbstractThe advantages of broadband communication networks are outlined. The activities developed in the framework of the Sub‐Project 5 of the C.N.R. Telecommunications Project are presented: the study and implementation of LANs and MANs using different communication links (optical fibres, satellite systems and also, for urban areas, microwave systems); the study of high speed optical communication networks (deflection networks and multi‐hop networks); the experiments on advanced services, carried out mainly for the scientific users. Two services are in particular outlined, teleeducation and telemedicine, on which experiments are planned with the aim of exploiting the capabilities of the broadband communication networks. Some indications are also given on the geographical areas, that are candidate for LANs‐MANs implementation and experiments performance.
Evolving system architecture towards B‐ISDN
Authors: Di Pino Duccio , Forcina Alessandro , Dogliotti Renato , Casale Salvatore , Maggi Wolfango , Berrini Alberto 
Published: September 2008

AbstractThe paper aims at describing a possible evolution strategy of a telecommunication network architecture which should provide users with a wide range of broadband services in a relatively short term. The discussion reflects the work carried out within the Italian «Progetto Finalizzato Telecomunicazioni» and it assumes, as starting points, the deployment of a digital network structure, together with the first introduction of the new Synchronous Digital Hierarchy (SDH) equipment.On the basis of the mentioned hypotheses, the exploitation in the network of the SDH capabilities, the role of Metropolitan Area Networks (MANs) and the issues related to the deployment of optical fibres in the distribution network are discussed with the target to provide a «grace‐ful» evolution path towards the future ATM‐based Broadband ISDN (B‐ISDN).
Metropolitan area networks: Standards, services and performance
Authors: Coronaro Massimo , Freschi Giuseppe , Iudica Melchiorre , Pavanelli Claudio , Roffinella Daniele 
Published: September 2008

AbstractThe paper, after a general survey of Metropolitan Area Network (MAN) issues, in which the market demand and recent trends in MAN concepts (e.g. relationship with Broadband Integrated Services Digital Network, B‐ISDN) are considered, examines the ongoing MAN related activities inside standard‐setting bodies such as IEEE (Institute of Electrical and Electronic Engineers) and ETSI (European Telecommunications Standards Institute). Emerging trends in architecture, protocols and services are reviewed.A more detailed characterization of the bearer services MANs are required to provide (i.e. connectionless, non isochronous connection oriented and isochronous) is then given, emphasizing their broadband nature and the related applications; the functions providing these services within the Distributed Queue Dual Bus (DQDB) framework are briefly described.The last section is devoted to a discussion of MAN performance. specifically in terms of fairness, focusing again on the DQDB protocol, which appears to be the most promising solution for MANs, and on possible improvements of its characteristics.
Digital transmission of HDTV on satellite channels
Authors: Cominetti Mario , Morello Alberto , Castellani Valentino , Visintin Monica , Casoria Atanasio , Losquadro Giacinto , Puccio Antonio 
Published: September 2008

AbstractThe perspectives for digital HDTV on satellite channels are examined at the light of the recent progress on bit‐rate reduction algorithms and on modulation and channel coding techniques. The experimental HDTV transmissions at 70 Mbit/s carried out by the RAI during the «1990 Football Worldcup» are shortly described. A preliminary configuration of the future HDTV network architecture has been identified, including terrestrial and satellite links. Two advanced modulation and coding systems, suitable for operating in the 30/20 GHz frequency range, have been studied by computer simulations: a) QPSK modulation and concatenated convolutional and Reed‐Solomon coding, and b) Trellis‐coded 8‐PSK modulation and concatenated Reed‐Solomon coding. The satellite channel has been optimized as regards the transmitting and receiving filters partitioning and the TWTA operating point. An example of design of a complete satellite chain at 30/20 GHz shows the feasibility of a 140 Mbit/s HDTV transmission system based on the described techniques.
Optical coherent systems in optical fibre LAN's and MAN's
Authors: De Marchis Giancarlo , Antodicola Claudio , Betti Silvello , Curti Franco , Grosso Guido , Iannone Eugenio , Matera Francesco 
Published: September 2008

AbstractA review of the potentialities offered by optical coherent techniques in LAN's and MAN's applications is presented. Some aspects concerning both topology and access techniques have been briefly discussed. The optical coherent systems and their technological requirements have been analyzed in order to show the advantages offered both in networking and broadcasting.
Semiconductor devices for photonic switching
Authors: Costa Bruno , Cocito Marco 
Published: September 2008

AbstractThe concept of all optical networks and the motivations for investigating them are briefly mentioned. Photonic switching is specifically considered and reasons for carrying out research on semiconductor based materials and devices for the implementation of optical switching functions are given. Afterwards the main physical properties that may find applications in photonic devices made of semiconductor materials are reviewed, with emphasis on QW structures and the associated important phenomena of Quantum Confined Stark Effect and Optical Stark Effect. The state of the art is then presented regarding the various devices needed in a photonic switching node: space/time switches and switching matrices (both of the electro‐optical and opto‐optical type), frequency switches, frequency converters and filters, digital memory elements made by optical bistable devices, logic optical devices.
Transputer based videocoders: Requirements and architectures
Authors: Brofferio Sergio , Mastronardi Giuseppe , Rampa Vittorio 
Published: September 2008

AbstractVideocoding algorithms possess a high degree of computation concurrency that can be exploited by parallel architectures. This paper presents the status of an applied research aimed at the implementation of a Transputer based videocoder for professional workstations. Basic algorithms are reviewed in terms of computation requirements and the ones specifically developed for ATM systems up to 2Mbit/s are quantitatively analyzed. Architectural tradeoffs are presented so that the demonstrator architecture can be defined in its hardware and software aspects. A video transputer module is defined and designed down to the logical level. Different partitioning of the algorithm execution is possible using a newly proposed «Farmer» Operating System.
Image coding with block DCT and motion compensation. Iwo different approaches
Authors: Bellifemine Fabio , Chimienti Antonio , Picco Romualdo , Muratori Mario , Stroppiana Mario 
Published: September 2008

AbstractMany approaches have been used to the purpose of image data compression. Each of them combines various techniques to exploit the redundancy of the image signal.In this paper two different approaches will be presented, analysed and compared. They have been developed by the CNR‐CSTV and the RAI Research Centre(1) respectively, in the framework of subproject 3.2 of the CNR «Telecomunicazioni» project. The goal is to define a coding scheme suitable for the bit‐rate compression of digital HDTV signals in order to cope with the characteristics of two kinds of channels: a synchronous channel at 70 Mbit/s and an asynchronous one with peak bit‐rate of 140 Mbit/s. The coded images must have a good quality for distribution networks.Both algorithms are based on the hybrid transform image coding using the 2D‐DCT to reduce the spatial correlation. In order to further decrease die temporal correlation a motion compensation technique is also applied. The aim of this paper is to describe the two algorithms and to investigate the main differences.
A new coding diversity technique
Authors: Benelli Giuliano 
Published: September 2008

AbstractDiversity techniques are widely used when the communication channel is affected.by heavy noise and disturbances. In the diversity techniques the same information is transmitted over m >1 channels. At the receiver side, the signals are combined together in order to reduce the bit error probability. In this paper a new diversity technique, using a suitable channel coding algorithm, is described. In this technique the information transmitted differs from one channel to the other one. The performance of this technique is obtained through a theoretical analysis. The application both to forward error correcting codes and automatic repeat request systems is described. The proposed technique is applied also to automatic repeat request schemes without diversity. The proposed technique permits to achieve in many cases higher performance than the classical diversity schemes.
Doppler correction for scattering matrix measurements of random targets
Authors: Tragi Karl 
Published: September 2008

AbstractA central topic in active microwave remote sensing is the measurement of polarimet‐ric scattering matrix time series. At least two successive measurements, employing orthogonal transmitter polarisations, are necessary to determine the full S‐matrix of an object. In many remote sensing applications, however, the observed targets experience small but non‐negligible variations even in the small time interval which is required to perform the S‐matrix measurement. In order to cope with this problem, a Doppler phase correction scheme can be applied which compensates for the deterministic mean target motion. The possible internal variation of a composite target due to the random motion of the target's individual scattering centres of particles, however, results in decorrelation of the consecutively measured S‐matrix columns and leaves significant statistical errors uncorrected. In the present paper the mean Doppler phase correction method and the related estimation errors are studied in greater detail, employing a quite general model of time‐variant random targets. It turns out that the critical quantity which determines the statistical accuracy of the Doppler correction is given by the ratio of the pulse repetition interval and the decorrelation time of the observed random target. The pulse repetition frequency of the radar measurement, hence, has to be chosen carefully in order to avoid large estimation errors in the S‐matrix determination. Matching the pulse repetition frequency properly to the decorrelation time of the observed target, on the other hand, allows the measurement and processing of polarimetric S‐matrix series with maximum information content on the target. The present statistical studies, this way, are of fundamental interest in many polarimetric remote sensing applications.
Signalling for B‐ISDN communications
Authors: Biocca Alfredo , Contini Enzo , Fioretto Giorgio , Piovano Luciano 
Published: September 2008

AbstractThe ATM based B‐ISDN offering a multiplicity of services in an integrated way represents the future communication network. One of the major points relates the signalling system to be adopted in order to fulfil the high flexibility the B‐ISDN requires.The first part of this document deals with the general requirements of the B‐ISDN signalling system, analyzing the new call and connection control concepts and giving some guide‐lines for a modelling activity. Considerations for a long‐term signalling system, which will have to handle a multiplicity of services, are also presented: multimedia services, complex call configurations, transitions among them during the lifetime of a call, and re‐configurations of attributes values for a connection are described.The second part proposes some basic issues for a preliminary example of signalling system which handles ATM point‐to‐point connections between two users or between a user and a specialized node, supporting services which require centralized resources within the network, such as connectionless or multimedia services.
An ATM switching testbed
Authors: Balboni Gian Paolo , Chiarottino Wolmer , Demichelis Carlo , Melen Riccardo , Pelizza Maurizio , Ravera Mauro 
Published: September 2008

AbstractAn experimental ATM switching node being developed by CSELT in the framework of CNR PFT is described.The node is built around a self‐routing buffered multistage switching network based oh a single type of integrated component. Each port of the network is connected to a packet processor which is in charge of interfacing with external ATM flows at 150 Mbit/s and of dealing with the ATM layer protocols.A distributed control structure is implemented, together with a software architecture which permits a rapid and easy introduction and testing of new services by abstracting system resources and defining a formal interface to application software.The access network developed within the ATM testbed is based on an active star shaped B‐NT which controls the access of the customer equipment to the local exchange and performs statistical multiplexing of the generated information flows.The terminals and interworking unit being provided in the ATM testbed have also been described, to give a picture of the services which will be considered in the experimentations.
A comprehensive analysis of DQDB
Authors: Conti Marco , Gregori Enrico , Lenzini Luciano 
Published: September 2008

AbstractThis paper reports on an extended simulation analysis of the asynchronous part of the DQDB MAC protocol. The analysis is divided into three parts. The first and second part deal with one priority level, while in the third part we analyze DQDB behavior with multiple priority level. In the first part we study DQDB inunderload conditionsi.e., when the offered load is lower than the medium capacity. Our results show that in underload, the access delay is not always as low as expected. In the second part we study DQDB inoverload conditions, i.e., when the offered load is higher than the medium capacity. Our results show that DQDB without the Bandwidth Balancing mechanism(BWB)is unfair and that the unfairness is dependent on the medium capacity and the bus length. When the BWB is enabled, DQDB fairness and performance, in the steady state, improve significantly. However, DQDB takes some time (depending on the BWB‐MOD value) to achieve the steady state during which the node quality of service is degraded. In the third part we show that the DQDB priority mechanism is not always effective.
User oriented satellite networks: Studies on utilization of transmission capacity in TDMA and TDMA/FDMA systems
Authors: Celandroni Nedo , Ferro Erina , Dossi Laura , Tartara Guido 
Published: September 2008

AbstractThe project to interconnect, in the C.N.R. environment, local area networks via satellite links at high speed, presents the problem of an efficient utilization of the transmit capacity of the satellite channel, as well as problems related to the terminal design. In particular, referring to satellite access schemes in FDMA and/or TDMA, the optimization of the transmission capacity utilization, according to the traffic requirements, is analyzed. Two systems, based on hybrid MF‐TDMA, are presented and synchronization problems are analyzed.