bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential applications of sonet in BISDN customer premises network management
Authors: Kramer M. , Lo C. N. , Salloum H. R. , Wolff R. S. 
Published: July 2007

AbstractFuture broadband customer premises networks (CPNs) may employ synchronous optical network (SONET) transmission, carrying asynchronous transfer mode (ATM) cells, to interconnect intrapremises stations. This prospect, driven by current standardization efforts in ANSI T1 committees and CCITT, can lead to ubiquitous and cost‐effective, high‐speed interfaces capable of supporting a variety of services. Similar to the way they will support operations functions for SONET network elements in future broadband public networks, the embedded overhead channels in the SONET frame structure can assist in management of the CPN. In this paper, we suggest means of supporting CPN management in the functions of network configuration, fault location and notification, and performance monitoring, by taking advantage of the SONET overhead capabilities.
Head of the line arbitration of packet switches with combined input and output queueing
Authors: Iliadis Ilias 
Published: July 2007

AbstractA single‐stage non‐blockingN × Npacket switch is considered. Data units may be stored before switching at the inputs as well as after switching at the outputs. Some output buffering capacity is intended to achieve high throughput, whereas an additional input buffering capacity keeps losses due to input‐buffer overflow reasonably low. The paper studies the impact on performance of the head of the line arbitration policy, i.e. the sequence which is used to transfer data units from the heads of input queues to each output queue. The investigation is based on two performance measures: the average delay and the maximum throughput of the switch. Closed‐form expressions for the FCFS, LCFS and the ROS policies are obtained. The result of the average delay with the FCFS policy leads to a lower bound, and that with the LCFS policy to an upper bound for the average delay, corresponding to an arbitrary symmetric policy which does not use information related to the state of the input queues. It is shown that the maximum throughput does not depend on the head of the line arbitration policy. It depends only on the output‐buffer size and the packet‐size distribution. The cases of fixed and exponentially distributed packet sizes are studied. The effects of asymmetric policies which result in different behaviours of some of the input queues is also considered.
Analysis of a discrete‐time queue with integrated bursty inputs in ATM networks
Authors: Zhang Zhensheng 
Published: July 2007

AbstractIn this paper, we carry out an exact analysis of a discrete‐time queue system with a number of independent Markov modulated inputs in ATM networks, using a generating function approach. We assume that the queueing system has an infinite buffer with M servers. The cell arrival process is characterized by a number of independent Markov modulated geometrical batch arrival processes. We first obtain the generating function of the queue‐size distribution at steady‐state in vector form, then derive an expression for the average queue‐size in terms of the unknown boundary probabilities. To obtain those unknown probabilities, we use the technique proposed in Reference 1. This involves decomposing the system characteristic function to evaluate the roots and solving a set of linear equations. One of the contributions of this paper is presented in Lemma 1, which characterizes the property of the underlying eigenvalues. For one special case of at least M‐1 cell arrivals during one slot at one Markov state and of at least M arrivals at all other states, the determination of the unknowns is straightforward. If every Markov modulated arrival process can be further decomposed into a number of i.i.d. two‐state, or three‐state, or even four‐state Markov modulated arrival processes, then each root can be obtained separately using an iterative algorithm. Numerical results are presented to validate the proposed traffic models against actual traffic measurements.
Architecture design for ATM statistical multiplexers
Authors: Chao H. Jonathan , Liew Soung C. 
Published: July 2007

AbstractBoth high‐speed packet switches and statistical multiplexers are critical elements in the ATM (asynchronous transfer mode) network. Many switch architectures have been proposed and some of them have been built, but relatively fewer statistical multiplexer architectures have been investigated to date. It has been considered that multiplexers are a special kind of switches which can be implemented with similar approaches. The main function of a statistical multiplexer, however, is to concentrate traffic from a number of input ports to a comparatively smaller number of output ports; ‘switching’ in the sense that a cell must be delivered to a specific output port is often not required. This implies that the channel grouping design principle, in which more than one path is available for each virtual circuit connection, can be applied in the multiplexer. We show that this technique reduces the required buffer memory and increases the system performance significantly. The performances of three general approaches for implementing an ATM statistical multiplexer are studied through simulations with various bursty traffic assumptions. Based on the best performing approach (sharing output channels and buffers), we propose two architecture designs to implement a scalable statistical multiplexer that is modularly decomposed into many smaller multiplexers by using a novel grouping network.
Performance evaluation study of signal design and equalization options for high‐bit‐rate digital subscriber line transceivers
Authors: Krzymien Witold A. , Bilodeau Thomas D. 
Published: July 2007

AbstractThis paper analyses different equalization, coding and signal constellation alternatives for the proposed high‐bit‐rate (800 kb/s) digital subscriber loop transmission interface. The simulation results presented in the paper demonstrate that bit rates above 1000 kb/s at acceptably low bit‐error rates (≤ 10−7) are feasible, if baseband transceivers with appropriate equalization and simple trellis coding are used. It is also shown that baseband transmission and Tomlinson precoding provide a significant performance advantage over bandpass transmission and decision‐feedback equalization, respectively.
Performance of in‐call buffer/window allocation schemes for short intermittent file transfers over broadband packet networks
Authors: Doshi Bharat 
Published: July 2007

AbstractWhile static open loop rate controls may be adequate for handling continuous bit rate (CBR) traffic, relatively smooth data traffic, and relatively low speed bursty data traffic over broadband integrated networks, high speed bursty data sources need more dynamic controls. Burst level resource allocation is one such dynamic control. Potential benefits and other issues for burst level resource parameter negotiations for bursty data traffic over high speed wide area packet networks have been discussed earlier.1–6 A detailed analysis of an adaptive buffer/window negotiation scheme for long file transfers using these concepts is presented in Reference 1. In this paper we discuss two burst level buffer/window negotiation schemes for short intermittent file transfers, focusing on the specific needs of such traffic streams. We develop closed network of queues models to reflect the behaviour of the proposed schemes. These models, while being simple, capture essential details of the control schemes. Under fairly general assumptions, the resulting network of queues is of product form and can be analysed using the mean value analysis. We use such an analysis to compare the proposed schemes and to determine appropriate sizes of trunk buffers to achieve the desired balance between bandwidth utilization and file transfer delay. The effects of other parameters on the performance of these schemes as well as on the buffer sizing rules are also discussed.Burst level (in‐call) parameter negotiation may be carried out by the end system with the network elements or by an interface system (access controller) with the broadband network elements. We discuss implications of this location as well as the needed protocol features. Finally, the service discrimination capabilities desired at the trunk controllers in switching nodes are briefly discussed.
Voiceband data speed discrimination
Authors: Benvenuto N. 
Published: July 2007

AbstractSome results of research to discriminate voiceband data signals of different speeds are reported. A discrimination technique based upon the autocorrelation envelope and second order moment of the complex lowpass data signal is introduced. Under ideal channel conditions, the discriminator, within a window of 128 ms of PCM data samples, classifies whether the signal is at 9600 bit/s, 4800 bit/s, 2400 bit/s, 1200 bit/s or 300 bit/s. Performance of the discriminator for signals in the presence of various analog impairments shows that this method is quite robust.
PDM: A versatile digital transmission system for video
Authors: Burgess G. D. 
Published: July 2007

AbstractThis report discusses a pulse density modulation (PDM) video transmission system. PDM is a one‐bit digital coding scheme with advantages of transparency due to an inherently extended signal bandwidth and relatively simple decoding; these make it ideal for a variety of applications.The system outlined is designed to carry a single analogue video channel, together with several sound channels, over a 140 or 280 Mbit/s digital transmission‐link. An alternative option to the sound channels will be to carry a 2.048 Mbit/s data channel. Since the analogue video input will be PDM coded, this will enable the system to carry video formats which have a flat base‐band frequency response requirement of in excess of 20 MHz (such as HDTV), allowing a large degree of flexibility in use.
Traffic modelling for packet communication networks
Authors: Stavrakakis Ioannis 
Published: July 2007

AbstractA general model for the description of traffic processes in packet communication networks is presented in this paper. The packet traffic generated by a network component is described in terms of a generalized Bernoulli process whose intensity depends on the state of the component. When the state space of the component is large, an approximate traffic characterization is proposed based on the dominant states. The latter characterization is shown to be well performing for the considered examples of practical network components. Based on the proposed general model, an analysis approach for multi‐component communication networks is presented. Numerical results illustrate the inaccuracy of the widely adopted i.i.d. modelling, the effectiveness of the proposed general model and the significant complexity reduction through the adoption of the approximate one.
Splice‐induced impairments on very‐high‐speed digital data communications over copper telephone networks
Authors: Sistanizadeh Kamran 
Published: July 2007

AbstractThe effects of splice‐induced crosstalk, insertion loss and echo on very‐high‐speed digital data communications over copper telephone networks are analysed and evaluated. Sealing current is used to mitigate the adverse effects of the splices. The specifications of sealing current (i.e. magnitude, shape, frequency of application) have significant ramifications on the operations of the digital communication systems. For proper operation of echo‐cancellers (i.e. fast adaptation and tracking) on full‐duplex transceivers operating at 800 kbit/s, and to achieve a bit error ratio of 10−7, the magnitude and the rate of the change of splice fluctuations must be controlled.It is shown that the effects of crosstalk and insertion loss are not as severe as the occurrence of echo due to rapid fluctuations of splice impedance. The admissible ranges of splice fluctuations for a series of worst‐case scenarios are computed, and their effects on the performance of the echo‐canceller are discussed.If the splice fluctuation is restricted to 0·1 Ω on a 20 Ω splice, with the splice in the vicinity of the transceiver, the echo is —36 dB with respect to the far‐end received signal, which is an acceptable level on a 9 kft subscriber loop with an American Wire Gauge of 26. However, quantification of the dynamics (i.e. the rate of change) of splice fluctuations requires laboratory experiments and field measurements.
Contention protocols for ring networks with large bandwidth‐delay products
Authors: Feldmeier David C. 
Published: July 2007

AbstractAs the bandwidth‐delay product of ring networks increases, conventional access protocols, such as the gated token protocol, become less efficient. We propose overcoming this problem with contention‐based access protocols. We discuss the necessary properties of any contention ring access protocol and present two specific proposals. Some simple analysis and simulation is done to determine the performance of these protocols. Our protocols are shown to have better end‐to‐end delay than a gated token protocol. We also simulate another contention protocol called the hybrid protocol, proposed by Bhargava, et al. It is shown that the simple protocols described in this paper have performance comparable to that of the more complex hybrid protocol on networks with high bandwidth‐delay products.
Optical broadband access using ATM on a passive optical network
Authors: Keller H. , Glade M. , Hartl B. , Horbach C. 
Published: July 2007

AbstractWithin the framework of the ‘FITL (fibre in the loop) evolution’, Siemens is developing a prototype based on a passive optical network (PON) for the economic provision of BISDN services in the subscriber access area. It provides 32 subscribers with BISDN access up to a maximum user data rate of 45 Mbit/s per subscriber. The information is transferred via ATM cells and PON‐specific overhead in both directions on the PON at a data rate of 155.52 Mbit/s. For transmission to the subscribers, the time division multiplex procedure (TDM) is used. For transmission in the opposite direction, a highly flexible time division multiple access procedure (TDMA) controls the access to PON for the subscriber‐side line terminations.In order to keep the transmission system inexpensive emphasis is placed on a digital calibration of the fibre loop delay, a burst transmitter at the subscriber side without amplitude recovery and a burst receiver at the exchange side with purely digital bit synchronization. However, to achieve these features a small part of data rate must be used as a PON specific overhead.
Dynamic expression patterns of leucine‐rich repeat containing protein 10 in the heart
Authors: Kim Ki‐Hyun , Kim Tae‐Gyun , Micales Bruce K. , Lyons Gary E. , Lee Youngsook 
Published: July 2007

AbstractLeucine‐rich repeat containing protein 10 (LRRC10) is a heart‐specific factor whose function remains unknown. Examination of the intracellular location of the gene products is a critical step in determining the biological functions of the protein. Our expression analyses in mice indicate that LRRC10 is exclusively expressed from the precardiac region in early embryos to the adult heart. LRRC10 expression is markedly elevated upon birth, suggesting its role in the embryonic as well as adult hearts. Of interest, LRRC10 exhibits dynamic intracellular expression patterns in cardiomyocytes. Cardiomyocytes from embryos and newborns show diffuse cytoplasmic and nuclear staining of LRRC10. In contrast, striking striations are observed in adult cardiomyocytes, which are colocalized with the markers for the Z‐line, sarcoplasmic reticulum (SR), and transverse (T)‐tubule by double immunostaining. Further investigation by electron micrographs places LRRC10 in a diad region where the SR interacts with the T‐tubule that locates along the Z‐line. Developmental Dynamics 236:2225–2234, 2007. © 2007 Wiley‐Liss, Inc.
Bone development in the femoral epiphysis of mice: The role of cartilage canals and the fate of resting chondrocytes
Authors: Blumer Michael J.F. , Longato Stefano , Schwarzer Christoph , Fritsch Helga 
Published: July 2007

AbstractIn mammals, the exact role of cartilage canals is still under discussion. Therefore, we studied their development in the distal femoral epiphysis of mice to define the importance of these canals. Various approaches were performed to examine the histological, cellular, and molecular events leading to bone formation. Cartilage canals started off as invaginations of the perichondrium at day (D) 5 after birth. At D 10, several small ossification nuclei originated around the canal branched endings. Finally, these nuclei coalesced and at D 18 a large secondary ossification centre (SOC) occupied the whole epiphysis. Cartilage canal cells expressed type I collagen, a major bone‐relevant protein. During canal formation, several resting chondrocytes immediately around the canals were active caspase 3 positive but others were freed into the canal cavity and appeared to remain viable. We suggest that cartilage canal cells belong to the bone lineage and, hence, they contribute to the formation of the bony epiphysis. Several resting chondrocytes are assigned to die but others, after freeing into the canal cavity, may differentiate into osteoblasts. Developmental Dynamics 236:2077–2088, 2007. © 2007 Wiley‐Liss, Inc.
In vivo quantum dot labeling of mammalian stem and progenitor cells
Authors: Slotkin Jonathan R. , Chakrabarti Lina , Dai Hai Ning , Carney Rosalind S.E. , Hirata Tsutomu , Bregman Barbara S. , Gallicano G. Ian , Corbin Joshua G. , Haydar Tarik F. 
Published: July 2007

AbstractFluorescent semiconductor nanocrystal quantum dots (QDs) are a class of multifunctional inorganic fluorophores that hold great promise for clinical applications and biomedical research. Because no methods currently exist for directed QD‐labeling of mammalian cells in the nervous system in vivo, we developed novel in utero electroporation and ultrasound‐guided in vivo delivery techniques to efficiently and directly label neural stem and progenitor cells (NSPCs) of the developing mammalian central nervous system with QDs. Our initial safety and proof of concept studies of one and two‐cell QD‐labeled mouse embryos reveal that QDs are compatible with early mammalian embryonic development. Our in vivo experiments further show that in utero labeled NSPCs continue to develop in an apparent normal manner. These studies reveal that QDs can be effectively used to label mammalian NSPCs in vivo and will be useful for studies of in vivo fate mapping, cellular migration, and NSPC differentiation during mammalian development. Developmental Dynamics 236:3393–3401, 2007. © 2007 Wiley‐Liss, Inc.
A parallel automatic routing technique based on local current comparison method—application of associative silicon retina
Authors: Cheng Gui‐Xin , Tanaka Mamoru 
Published: July 2007

AbstractThis paper proposes a new local current comparison method to search for the routing path. In the proposed method, the routing plane is represented by a resistive network. A voltage is provided to the start and the end pins to be connected, and the routing path is determined from the current distribution in the equilibrium state. Thus, the local current of the edges connected to each node of the routing path is maximized. By this local current comparison method, the routing path is determined along the direction of the maximum current and several nets can be routed while avoiding the competition.The routing method for the multipin net also is proposed based on the local current comparison method. Since the potential distribution of the nodes in the resistive network is an approximate solution of the equipotential line distribution of the static electric field, it is shown that the optimal or quasi‐optimal short routing path can be determined. Using the multilayer resistive network, the multilayer routing can also be realized. Then the automatic routing method is proposed where more than one net can be routed in parallel by modifying the specification of voltages according to the result of the previous current distribution obtained by the local current comparison method.A method to locate the bottleneck (BN) of the net also is presented. The proposed local current comparison method is related closely to the node neighborhood analysis from the viewpoint of the cellular neural net, based on the energy minimization method. The method is especially suited to the dedicated hardware implementation by the mixed analog‐digital chip.
Proposal of median‐type fuzzy filter and its optimum design
Authors: Arakawa Kaoru , Arakawa Yasuhiko 
Published: July 2007

AbstractThis paper proposes a median‐type fuzzy filter, aiming at the signal estimation in the case where the impulse and white Gaussian noise are superposed on the signal with sudden changes, such as the image signal. The filter is realized by generalizing the fuzzy filter previously proposed by the authors. In the previously proposed fuzzy filter, the signal point to be estimated is taken as the reference point and the signal is estimated by determining the input signals relatively close to the reference point, using the fuzzy clustering; whereas the filter proposed in this paper uses the median value of the input signal sequence as the reference point and the signal is estimated by determining the input signals close to that reference point using the fuzzy clustering. The signal is estimated by determining the center of gravity of the cluster of the points close to the median. Furthermore, in the proposed filter, the optimum design is realized by learning with respect to appropriate training signals. It is in general not possible to decide definitely whether or not the input signal is close to the median, and thus the fuzzy clustering is effective since it takes into consideration the ambiguity of the signal. By introducing the fuzzy clustering, it is shown in particular that an effective signal estimation is realized for the signal with subtle changes.
A CAM‐based hardware implementation of the improved line‐search algorithm
Authors: Kubota Kazuto , Sato Masao , Ohtsuki Tatsuo , Suzuki Kei 
Published: July 2007

AbstractIn the routing process in VLSI and PCB, the “gridless router” has been considered where the routing is executed without using a grid. The improved line search algorithm is one of the gridless routers where the linesearch algorithm is extended so that the route search procedure is executed on a linear memory space in a polynomial time. The search of the route with the minimum bends is ensured. However, the algorithm has a problem in that the route is obtained by iterating the search of the two‐dimensional figures and the computational complexity ofO(nlog2n) at the minimum andO(n2) in the worst case is required for the layout area composed ofnvertices.This paper notes that the complexity of solving the two‐dimensional figure search problem can be suppressed by using the associative memory and presents an algorithm for the improved line search using the associative memory where the time and space complexity isO(n). The proposed algorithm is implemented on the associative processor and the result is compared to the result of implementation on the general‐purpose computer.
Vector quantization with hypercolumnar clusters
Authors: Kohata Minora , Takagi Tasuku 
Published: July 2007

AbstractThis paper proposes a new vector quantization method which can reduce search complexity and code book memory size by reducing the number of code vectors without increasing quantization distortion. This method uses hypercolumnar clusters; and an input vector is quantized to a cluster, the center axis of which is nearest to the input vector. Thus, one vector and one scalar must be coded and transmitted. The proposed method was applied to four geometrically different distributions and LPC cepstra of speech signals. As a result, the number of code vectors was decreased compared with that in an ordinary vector quantizer, in all of the forementioned distributions. Then the reduction of memory size and search complexity were evaluated.The excessive bits required for the scalar quantization in this method also were studied.