bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantum Kinetic Theory for Laser Plasmas. Dynamical Screening in Strong Fields
Authors: Bonit M. , Bornath Th. , Kremp D. , Schlanges M. , Kraeft W. D. 
Published: July 2007

AbstractA quantum kinetic theory for correlated charged‐particle systems in strong time‐dependent electromagnetic fields is developed. Our approach is based on a systematic gauge‐invariant nonequilibrium Green's functions formulation. Extending our previous analysis [1] we concentrate on the selfconsistent treatment of dynamical screening and electromagnetic fields which is applicable to arbitrary nonequilibrium situations. The resulting kinetic equation generalizes previous results to quantum plasmas with full dynamical screening and includes many‐body effects. It is, in particular, applicable to the interaction of dense plasmas with strong electromagnetic fields, including laser fields and x‐rays. Furthermore, results for the modification of the plasma screening and the longitudinal field fluctuations due to the electromagnetic field are presented.
Equilibrium Properties of H‐Plasma
Authors: Arkhipov Yu. V. , Baimbetov F. B. , Davletov A. E. , Ramazanov T. S. 
Published: July 2007

AbstractThe equilibrium properties of the dense semiclassical hydrogen plasma are investigated by chain of Bogolyubov equations. The pseudopotential model, taking into account both short‐range quantum‐mechanical effects and long‐range many‐particle screening ones, is proposed. The equation of state of hydrogen plasma is investigated.
A restaining method to restore faded fluorescence in tissue specimens for quantitative confocal microscopy
Authors: Huisman André , Ploeger Lennert S. , Dullens Hub F. J. , Beekhuis Jan T. C. , Diest Paul J. van 
Published: July 2007

AbstractThe aim of this study was to develop a procedure to remove the TO‐PRO‐3 fluorescent dye from tissue sections and restain with TO‐PRO‐3, still allowing calculation of DNA content and distribution by confocal laser scanning microscopy (CLSM). This would allow repeated measurements on the same tissue sections and prevents loss of tissue material from valuable clinical samples. Thick sections (14 μm) were cut from a paraffin block of adrenal tissue and stained using TO‐PRO‐3. Image stacks were acquired by CLSM. Thereafter, three destaining approaches were tested based on incubation, at different temperatures and durations, in the medium that is normally used to dissolve TO‐PRO‐3. The same areas were imaged again to measure residual fluorescence and were subsequently restained and imaged again. The intensity of the images acquired after initial staining and restaining were compared. A number of 3‐D (texture) features computed after segmentation of nuclei were compared as well. The best destaining result was obtained by incubation of sections at 37°C in preheated medium twice for 20 min. On average, the 3‐D feature values were comparable with those after initial staining. With the described protocol it is possible to remove TO‐PRO‐3 fluorescence from tissue sections that can successfully be restained with minimal influence on fluorescence intensity and nuclear chromatin distribution. © 2007 International Society for Analytical Cytology
France telecom's introduction of switched broadband business services
Authors: Richard C. , Riviere P. , Guiomar J. , Poirier A. , Le Bihan E. , Veyres C. 
Published: July 2007

AbstractIn order to cope with the growth of video transmissions in France, France Telecom will commercially introduce switched broadband business services by June 1990. A broadband network based on a meshed network of optical fibres will provide one‐way point‐to‐multipoint (including point‐to‐point) connections, available on reservation. This network will link non‐blocking 32 × 32 or 64 × 64 space switches that can cross‐connect different signals, including analog SPFM (square pulse frequency modulation) video, HDB3 34 Mb/s and CMI 140 Mb/s digital signals.
A connection acceptance algorithm for ATM networks based on mean and peak bit rates
Authors: Wallmeier Eugen 
Published: July 2007

AbstractA connection acceptance algorithm for pipes in ATM networks is presented, which allows statistical multiplexing of heterogeneous ATM traffic. The decision to accept an incoming connection is based on the mean and the peak bit rates of the incoming and existing connections. Conditions are presented, under which the algorithm guarantees that the cell loss probability of every virtual connection does not exceed a predefined permissible probability. Examples are presented which show the gain which can be reached by statistical multiplexing.
Traffic control architectures for integrated broadband networks
Authors: Ash Gerald R. , Schwartz Steven D. 
Published: July 2007

AbstractFuture broadband ISDN networks will provide a multiplicity of services on integrated transport networks. Switching nodes, interconnected by a flexible transmission network, provide connections for voice, data and broadband services. These connections are distinguished by estimated resource requirements, traffic characteristics and design performance objectives. This paper examines alternative traffic network architectures for integrated broadband networks, and provides integrated network routeing methods, bandwidth allocation strategies and traffic/routeing control plans for these networks. These architectures extend dynamic routeing control concepts to integrated broadband networks, and suggest perhaps radically different traffic architectures to which broadband networks might evolve. Strategies are examined for dynamic traffic routeing and dynamic trunk capacity routeing, which can adapt to load variations in customer requirements or to network resource failure conditions. Bandwidth allocation procedures are investigated which manage network bandwidth according to a virtual trunk concept, in which dynamic reservation controls are placed on the number of connections for each service category. We analyse the alternative traffic network architectures, for example broadband networks. The examples show that the architectures provide, to varying degrees, the advantages of increased network efficiency, improved customer service and increased network flexibility. Fully shared ring networks which integrate dynamic traffic and trunk capacity routeing yield many of these advantages and also provide greatly simplified network operation along with maximum flexibility to apportion network resources, especially when implemented with asynchronous transfer mode (ATM) technology. Such a traffic architecture provides a possible direction for future integrated broadband networks.
Multipoint connection routeing
Authors: Lee Kyoo J. , Gersht Alexander , Friedman Anda 
Published: July 2007

AbstractAmong other potential services envisioned for broadband ISDN networks, multipoint connnection services have drawn much attention from the standards arena as well as research communities. These services include conference calls, video lectures, etc. where more than two endpoint CPEs are involved in communication. In this paper we investigate representative multipoint connection routeing algorithms from a number of viewpoints: computational complexity, call set‐up complexity, dynamic reconfiguration, robustness to node failures and bandwidth efficiency. These algorithms are either known in the literature or a simple generalization of point‐to‐point routeing algorithms. An interesting conclusion of our study is that the use of multiple point‐to‐point connections for multipoint calls is a viable solution in many cases of interest. This solution would eliminate much of the additional call‐handling complexity that may be otherwise introduced by more sophisticated multipoint routeing algorithms.
A multichannel, bidirectional single‐wavelength, optical video link over a single fibre
Authors: Shklov Shane J. 
Published: July 2007

AbstractOver the past year the Manitoba Telephone System, working with both Catel in California and Cabletel in Toronto has developed a unique optical architecture. In comparison to conventional fibre architectures, this structure has reduced the cost and complexity while increasing the reliability and capacity without sacrificing technical performance. This multinode, multichannel, bi‐directional, single wavelength video conference structure is in use between hospitals in the province of Manitoba. Details of this configuration along with its performance are discussed.
A survey of multistage interconnection networks in fast packet switches
Authors: Chen Xiaoqiang 
Published: July 2007

AbstractThis paper comprises a broad survey of multistage interconnection networks (MINs), which are incorporated into the underlying fabric of fast packet switches for use in broadband ATM networks. A general classification of MINs based on network functionality and blocking characteristics in the context of fast packet switches is presented in order to emphasize the fundamental principles which differentiate the network architectures. For each class of network, important theoretical results are given and the underlying design principles are explained with the best known explicit examples. Special emphasis is given to the implementation complexities and control strategies of individual approaches.
Multiserv: An ATM based residential SPN for the belgian broadband project
Authors: van Engelshoven Rob 
Published: July 2007

AbstractThe paper describes the ATM based MULTIserv subscriber premises network (SPN) intended for residential and small business use. The system is optimized for users requiring a low number of broadband connections and having a large demand for distributive services such as CATV. This SPN may be used whenever call acceptance is done according a peak bandwidth allocation policy.Although the MULTIserv access system is extremely simple, both continuous and variable bit‐rate services are supported. Traffic calculation and simulations show that the services most susceptible to jitter, i.e. the synchronous, can be guaranteed for mean network access loads of up to 95 per cent, provided that traffic source shaping is performed.Through the equal S and T interface the modular concept allows for star, bus and tree‐like topologies. The low functionality enables low‐cost solutions through high system integration.
Statistical multiplexing gain for variable bit rate video codecs in ATM networks
Authors: Heeke Helmut 
Published: July 2007

AbstractAsynchronous transfer mode (ATM) broadband networks will support variable bit rate video codecs, which are capable of maintaining a constant picture quality. To demonstrate this capability, a prototype hardware video coder has been developed in the Siemens Central Communications Laboratories. The prototype uses interframe coding, combined with a discrete cosine transform, and is able to reproduce the original picture quality, independent of signal sources or picture material used.A gain in transmission efficiency is expected when several video sources share a common ATM channel (‘statistical multiplexing’). This paper reports on a series of measurements that have been performed using this coder for a large variety of video sources to determine the possible gain in transmission efficiency.The main results are: for realistic video phone scenes, up to about three times the number of signals can be transmitted compared to transmision with constant rate and the same picture quality, if the output signal of the coder has been smoothed over a period of one frame. Smoothing over shorter periods reduces the potential gain substantially. The statistical multiplexing gain increases with the duration of the picture sequences due to the criterion of constant picture quality. It varies very little with the acceptable packet loss rate.
A survey of research and standards in high‐speed networks
Authors: Li Victor O. K. , Chang Jin‐Fu , Lee Kuo‐Chun , Yang Tien‐Shun 
Published: July 2007

AbstractThis paper surveys research and standards in high‐speed networks. It first classifies high‐speed networks according to the area of coverage. Secondly, it discusses the switches. Then, it examines network management protocols: media access control, routeing, flow control and error control. Finally, it investigates current hig‐speed network standards: DQDB, FDDI, ATM, and SONET.
An efficient method for computing cell loss probability for heterogeneous bursty traffic in ATM networks
Authors: Jabbari Bijan , Yegenoglu Ferit 
Published: July 2007

AbstractIn this paper, we present an approximation for the probability of cell loss of heterogeneous bursty traffic in broadband integrated packet networks based on the asynchronous transfer mode. The sources considered here alternate between active and silent periods and are characterized by their peak and average transmission rates. The cell loss probability is obtained by considering only the number of active sources at a given time and computing the amount of traffic that exceeds the link capacity. Since the amount of buffered excess traffic is not considered in this computation, this approximation is actually an upper bound of the cell loss probability. The numerical efficiency of this bound enables it to be used as a measure based on which robust and simple resource allocation strategies can be developed for bursty sources. Comparison of this bound with the simulation results has shown that the bound is close to the actual loss probabilities especially for large burst lengths and high utilizations.
Optimized nested threshold cell discarding for ATM overload control
Authors: Petr David W. , Frost Victor S. 
Published: July 2007

AbstractThis paper deals with overload control in asynchronous transfer mode (ATM) networks via priority cell discarding mechanisms governed by a set of nested queue fill thresholds. Specifically, we address the problem of finding the optimal set of discarding thresholds, for an arbitrary number of priorities, under two different performance scenarios. In the first scenario, we minimize the expected discarding cost (a performance penalty) for a given offered load using stochastic dynamic programming. In the second scenario, we maximize the offered load subject to constraints on cell loss (discarding) probabilities using an efficient search technique developed specifically for this problem. Our results illustrate that nested threshold discarding systems can perform significantly better under either scenario than a system without discarding priorities. We characterize the performance advantage over ranges of system parameter values and briefly study the use of sub‐optimal, non‐adaptive thresholds.
An analytical technique for the derivation of the delay performance of ATM switches with multiserver output queues
Authors: Bruneel Herwig , Steyaert Bart , Desmet Emmanuel , Petit Guido H. 
Published: July 2007

AbstractIn this paper, a discrete‐time multiserver queueing system with infinite waiting room and general independent arrivals is considered. The delay performance of such a system, under a first‐come‐first‐served queueing discipline, is evaluated by means of a purely analytical technique. Specifically, explicit formulae are derived for such quantities as the probability generating function, the mean value and the variance of the delay. The results of the study are useful, for instance, in the context of fast packet switching with output queueing, where the switching elements have their output ports organized in groups, each group corresponding to a separate output queue.
Precise UPC scheme and bandwidth allocation methods for ATM‐based bisdn characterized by wide‐ranging traffic parameter values
Authors: Yamanaka Naoaki , Sato Youichi , Sato Ken‐Ichi 
Published: July 2007

AbstractThis paper proposes an ATM traffic management method that combines a deterministic source traffic descriptor, a deterministic usage parameter control (UPC) algorithm, and a conservative statistical bandwidth allocation method. The source traffic descriptor is based on sliding time interval‐type descriptors for both the peak‐rate and the average‐rate. A UPC method which combines a sliding‐window‐type circuit and a two‐phase credit‐window‐type circuit for widely‐ranging traffic parameter values is proposed. The method is precise and accurate, and requires only a small amount of hardware. The bandwidth allocation method uses the worst pattern that can be transmitted through the proposed UPC circuit. The proposed traffic management method not only guarantees the QOS of all connections, but also allows for large statistical multiplexing gain. The proposed method, therefore, makes it possible to create a more effective BISDN, one that can offer cost‐effective broadband VBR services.
Path enumeration and hot‐potato routeing analysis in multihop networks
Authors: Ayanoǧlu Ender , Caballero Richard J. 
Published: July 2007

AbstractUsing a labelling of the edges of the network graph for a multihop network and a Taylor series expansion of the transfer function of the resulting signal flow graph, we calculate the number of paths of a given length in the multihop network. The derivative of the transfer function and a fixed point algorithm yield the average delay as a function of the packet arrival rate.
A parametric optimization approach to admission control and bandwidth assignment in hybrid TDM networks
Authors: Aicardi Michele , Bolla Raffaele , Davoli Franco , Minciardi Riccardo 
Published: July 2007

AbstractThe access to a multiservice synchronous TDM network is considered, where hybrid frames are used to carry two basic traffic types (a circuit‐switched isochronous and a packet‐switched asynchronous one), generated by several users. Each user is assigned a portion of the total available bandwidth, in terms of slots/frame, which is dynamically allocated between the two traffic types at the user premises, by means of a local randomized decision rule. The users' bandwidth shares (capacities) are allocated by a centralized agent, whose goal is to minimize a global cost function that accounts for packet delays and call blocking of the entire process. Parametric optimization problems for the central agent are defined and the application of suitable descent techniques is shown, with the cost function extending over a finite and an infinite time horizon, respectively. The specific nature of the optimization problems is discussed, and numerical examples and simulations are presented that illustrate the effectiveness of the method.
Performance evaluation of an adaptive GSM receiver with frequency‐selective fading and adjacent‐ and co‐channel interference
Authors: Luise Marco , Reggiannini Ruggero 
Published: July 2007

AbstractThis study represents the sequel and conclusion of a previous one already published in this Journal a few issues ago.1 In that article, we tackled the problem of evaluating theoretically the performance of an adaptive MLSE receiver for MSK signals on a frequency‐selective stationary radio propagation channel, and we validated the theoretical findings (in the form of upper and lower bounds to the BER of the receiver) by means of computer simulations. In the present paper, we report on the performance of the very same scheme of channel‐estimator‐plus‐Viterbi‐equalizer receiver for mobile communications in a more realistic operating environment. In particular, we completely encompass here the groupe spécial mobile (GSM) transmission format, based on the Gaussian minimum shift keying (GMSK) modulation scheme and on narrowband time‐division multiple access (TDMA) transmission. Also, we remove the assumption of a time‐invariant propagation channel, assuming the recommended standard GSM channels as benchmark transmission conditions. Finally, with the aid of extensive computer simulations, we analyse the sensitivity of the MLSE receiver to unwanted co‐channel and adjacent‐channel interference coming from other users of the mobile cellular GSM system.
On the non‐blocking conditions of self‐routeing multistage interconnection networks
Authors: Ferrari G. , Lenti M. , Pattavina A. 
Published: July 2007

AbstractThis paper studies the non‐blocking conditions of a genericN × Nmultistage interconnection network, such as an omega network or ann‐cube network, in which only one path connects any inlet to each outlet and different I/O paths can share interstage links. It is widely known that any of these networks is non‐blocking for a compact and monotone pattern ofk≤NI/O paths. Recently it has become very important to show the network non‐blocking property for permutation sets, wider than the compact and monotone, which are usually encountered in broadband ATM networks. By using a new approach based on the concept of distance between I/O paths, we show here that these networks are non‐blocking for a set of I/O paths obtained by shifting cyclically the inlets of a compact and monotone pattern of I/O paths by an arbitrary number of steps.
Coupling between tilted Gaussian beam and graded‐index multi‐mode fibre
Authors: Sun Z. J. , Jannson T. 
Published: July 2007

AbstractThis paper is a comment on the paper presented by Shimazu and Kikuchi,11 ‘A time and wavelength division fiber loop distribution system with acousto‐optic tunable filters’. Specifically, a number of assumptions made in their paper regarding channel loss and crosstalk make it difficult to apply to real‐world system evaluations.
On the effects of a spacecraft subcarrier unbalanced modulator
Authors: Nguyen Tien Manh 
Published: July 2007

AbstractThis paper presents mathematical models with associated analysis of the deleterious effects which a spacecraft's subcarrier unbalanced modulator has on the performance of a phase‐modulated residual carrier communications link. The undesired spectral components produced by the phase and amplitude imbalances in the subcarrier modulator can cause (1) potential interference to the carrier tracking and (2) degradation in the telemetry bit signal‐to‐noise ratio (SNR). A suitable model for the unbalanced modulator is developed and the threshold levels of undesired components that fall into the carrier tracking loop are determined. The distribution of the carrier phase error caused by the additive White Gaussian noise (AWGN) and undesired component at the residual RF carrier is derived for the limiting cases. Further, this paper analyses the telemetry bit signal‐to‐noise ratio degradations due to undesirable spectral components as well as the carrier tracking phase error induced by phase and amplitude imbalances. Numerical results which indicate the sensitivity of the carrier tracking loop and the telemetry symbol‐error rate (SER) to various parameters of the models are also provided as a tool in the design of the subcarrier balanced modulator.