bluuebunny/crossref_metadata_2025 huggingface dataset:
A Prototype Growable 2.5 Gb/s ATM Switch for Broadband Applications
Authors: Eng K. Y. , Pashan M. A. , Spanke R. A. , Karoll M. J. , Martin G. D. , Obara H. , Ueda H.
Published: December 2019

A prototype 2.5 Gb/s ATM switch fabric has been developed for flexible broadband applications. The prototype configuration supports multiple standard line card interfaces, e.g., STM-1 (155 Mb/s), STM-4c (622 Mb/s) and STM-16c (2.5 Gb/s). The ATM cells are extracted from the payload of these SDH signals and are multiplexed inside the fabric to an internal equivalent cell rate of 2.5 Gb/s. Routing is done subsequently on a cell-by-cell basis according to the cell header address information (VPI and/or VCl). The core fabric of the switch is therefore a 2.5 Gb/s ATM switch. The fabric is designed using the theory of the Growable Switch Architecture guaranteeing the best possible delay-throughput performance for arbitrary traffic distributions for independent inputs. In this prototype implementation, careful considerations have been given to optimize various aspects such as physical size, physical growth, power consumption, protection switching, maintenance and reliability. The core 2.5 Gb/s fabric prototype can grow from 8 x 8 (supporting up to 128 STM-1 interfaces) to larger sizes (e.g., 64 x 64, supporting up to 1024 STM-1 interfaces). Considerations for substantially larger switch sizes have also been taken into account in the design. Descriptions of our initial prototype and its evolution to larger switch dimensions are discussed.
A Queueing Model of a Bufferless Synchronous Clos ATM Switch with Head-of-Line Priority and Push-Out
Authors: Nilsson Arne A. , Perros Harry G. , Lai Fuyung
Published: December 2019

We consider a synchronized bufferless Clos ATM switch with input cell processor queues. The arrival process to each input port of the switch is assumed to be bursty and it is modelled by an Interrupted Bernoulli Process. Two classes of cells are considered. Service in an input cell processor queue is head-of-line without preemption. In addition, push-out is used. That is, a high priority cell arriving to a full queue takes the space occupied by the low priority cell that arrived last, as long as the cell is not in service. Each cell processor queue is modeled as a priority IBP/Geo/1/ K + 1 queue with push-out. We first present an exact analysis of this priority queue. The results obtained are then used in an approximation algorithm for the analysis of the ATM switch. Validation tests using simulation data shows that the approximation algorithm has a good accuracy.
Towards a Gigabit IP Router
Authors: Asthana Abhaya , Delph Catherine , Jagadish H. V. , Krzyzanowski Paul
Published: December 2019

In this paper we illustrate the application of SWIM's Active Storage Element (ASE) module in constructing high performance IP routers. The logic associated with each ASE is a wide-instruction-word micro-programmable engine, that has been specially designed to efficiently perform operations such as pointer dereferencing, memory indirection, bounds checking, and so forth. This makes it well suited to performing operations such as parsing of the IP header, routing table lookup, checksum computation and exception processing. Our results show that a single ASE running at 20 MHz can process 400,000 packets per second: well over that required to sustain a gigabit router. Multiple ASEs can be used in parallel to achieve even higher processing rates.
NSF Implementation Plan for Interagency Interim NREN
Authors: Aiken Robert J. , Braun Hans-Werner , Ford Peter , Claffy Kimberly
Published: December 2019

This document outlines an architecture and implementation plan for the National Science Foundation's Interagency Interim National Research and Education Network (NREN) component of the HPCC Program. The Interagency Interim NREN is intended as a near term research and development program to extend the capabilities and breadth of connectivity of today's research and education (R&E) networks. This network will provide not only the opportunity for agency backbones and mid-level networks to connect to NSF-funded networks, but also act as a limited testbed for new technologies in the migration to a gigabit NREN. In order to ensure a smooth transition to a national gigabit network infrastructure which can support the combined requirements of federal agencies, the U.S. research and educational institutions, and industrial collaborations with U.S. R&E institutions, the National Science Foundation has collaborated with other federal agencies in establishing this framework for the Interagency Interim NREN.
Design of a Gigabit Host-Network Interface
Authors: Sterbenz James P.G. , Parulkar Gurudatta M.
Published: December 2019

We have proposed a new architecture called Axon that meets the challenges of delivering high network bandwidth directly to applications. Its novel aspects include: an integrated design of host and network interface hardware, operating systems, and communication protocols; the proper division of hardware and software function; reorganisation of end-to-end protocols to take advantage of the increased functionality of the emerging high speed internetworks; and a pipelined interface between the network and host memory with no packet buffering.

The pipelined network interface performs critical per packet processing in hardware as packets flow through the pipeline, without imposing any store-and-forward buffering of packets. This requires the design of error and flow control mechanisms to be simple enough for implementation in the network interface hardware, while providing the functionality required by applications.

This paper describes the design of the host-network interface, and, in particular, the hardware design of the critical per packet processing with emphasis on error and flow control. An extensive simulation model of the network interface hardware has been used to determine the feasibility and performance of hardware implementation of these functions.
Deflection Routing in Regular MNA Topologies
Authors: Gburzyński Pawel , Maitan Jacek
Published: December 2019

We introduce MNA (Multigrid Network Architecture) – a networking concept aimed at applications calling for very high transmission rates (of the order of gigabits per second). An MNA network is a collection of photonic switches linked by optical channels. A switch is responsible for relaying incoming packets along the best available routes to their destinations. Packets that cannot be relayed optimally are deflected, i.e., relayed along suboptimal paths. The technology for building MNA switches has been developed in Lockheed Palo Alto Research Lab, [20]-[22]. In this paper, we discuss the logical aspects of MNA, present a model for investigating the performance of MNA in regular topologies, and apply this model to a number of network configurations.
Analysis of Dynamic Congestion Control Protocols — A Fokker–Planck Approximation
Authors: Mukherjee Amamath , Strikwerda John C.
Published: December 2019

We present an approximate analysis of a queue with a dynamically changing input rate that is based on implicit or explicit feedback information. This is motivated by proposals for adaptive congestion control algorithms, [6] and [15], where the sender's window size at the transport level is adjusted based on perceived congestion level of a bottleneck node. We develop an analysis methodology for a simplified system; however, it is powerful enough to answer important questions regarding stability, convergence (or oscillations), fairness and the significant effect that delayed feedback plays on performance.

This paper quantitatively identifies the cause of the these effects, vis-a-vis the system parameters and properties of the algorithm used. Several conservation laws and balance equations governing this system are given.

The model is fairly general and can be applied to evaluate the performance of a wide range of feedback control schemes. It is an extension of the classical Fokker-Planck equation. Because the Fokker-Planck equation models diffusion, it addresses traffic variability, and in a sense, extends earlier fluid approximation analyses.
IDPR: An Approach to Policy Routing in Large Diverse Internetworks
Authors: Steenstrup M.
Published: December 2019

Route generation and message forwarding in large diverse internetworks is subject to multiple service-related constraints, referred to as policies, imposed both by the service providers (in terms of offered services and restrictions on these services) and by the users (in terms of service requirements). We present an approach to policy routing, called Inter-Domain Policy Routing (IDPR), designed to operate in an internetwork composed of thousands of separately administered networks. The primary objective of IDPR is to provide traffic with routes that satisfy the users' service requirements while respecting the service providers' service restrictions. In this paper, we present an overview of IDPR, concentrating on those aspects of IDPR that make it well suited to policy routing in large internetworks with diversity among users and service providers.
On the Design of a Multigigabit IP Router
Authors: Tantawy Ahmed , Koufopavlou Odysseas , Zitterbart Martina , Abler Joseph
Published: December 2019

The emergence of gigabit speed networks hinges upon the existence of high performance internetworking units, such as IP routers. In this paper, we present an architecture and we discuss the implementation of a multigigabit IP router. For this implementation, two special purpose VLSI chips are required; the rest can be built using off-the-shelf components. IP header processing of received packets is handled by a specialized chip. Memory management, another well-known performance bottleneck, is simplified and efficiently implemented using special VLSI support. Searching for the next hop address in the routing table, which is the major contributor to the delay in traditional IP protocol implementations, is significantly reduced by using a special configuration of Content Addressable Memories (CAMs).
A Two-Level Flow Control Scheme for High Speed Networks
Authors: Gong Fengmin , Parulkar Gurudatta
Published: December 2019

New applications such as multimedia remote conferencing demand network transport services with performance guarantees. At the same time, new networking technologies such as ATM are gearing towards providing services on a reservation-and-guarantee basis. In the light of the new application and networking environments, it seems necessary to revisit many of the transport protocol issues in search for more efficient ways to address them. This paper proposes using an explicit rate control together with a simple window control for flow control in high-speed networks with resource reservations. The design justifications, the evaluation study, and the implementation results are presented. Particularly, the idea of hard ACK and soft ACK in the context of end-to-end flow control is explored through simulation and the results are discussed.
Policy Control of Inter-Administrative Domain Data Communication
Authors: Kumar Brijesh , Crowcroft Jon
Published: December 2019

In this paper we have attempted to synthesise the policy requirements of Administrative Domains and map them to the subject-object matrix normally used for access control models. This facilitates the analysis of the policy controls provided by the policy routing protocols. The hybrid model proposed by us combines the existing IDRP proposal with an alternative source routing proposal. We believe that such a unified policy routing environment will be able to meet the most policy requirements outlined in the first part of the paper.
Dynamic Reconfiguration in Multihop WDM Networks
Authors: Rouskas George N. , Ammar Mostafa H.
Published: December 2019

We consider multichannel multihop lightwave networks with stations equipped with a small number of transmitters and receivers. By assigning wavelengths to the receivers and transmitters at each station, one can define the logical connectivity of the network independently of the underlying physical topology. The advent of fast tunable optical transmitters and receivers makes it feasible to dynamically update the network connectivity to accommodate traffic demands that vary over time. Of major concern in such design is how the connectivity should react to changes in traffic patterns. The problem is formulated as a Markovian Decision Process and the properties of the optimal configuration policy are identified. These properties are then used to develop an algorithm for obtaining policies that make decisions similar to the decisions of the optimal policy. A procedure is also proposed to manage the large state space for systems with a large number of stations.
Fair DQDB: The Rotating Slot Generator Scheme
Authors: Karvelas Dennis , Papamichail Michail , Polyzos George C.
Published: December 2019

We introduce the Rotating Slot Generator (RSG) scheme for dual bus architectures, a medium access control protocol appropriate for high capacity Metropolitan Area Networks (MANs). This scheme uses the looped bus architecture of the Distributed Queue Dual Bus (DQDB) MAN, in which slot generator hardware is incorporated into all stations. Its difference from DQDB is that during its operation the responsibility for generating slots moves periodically from station to station around the loop. Thus, station positions relative to the slot generator change continuously and, therefore, there are no favorable locations on the busses. We first present the system architecture and the RSG protocol. Then, we carry out a thorough investigation of the performance of the RSG scheme through simulation. We demonstrate the fairness of the protocol with respect to throughput and delay, and evaluate its performance in underload and overload conditions, under both a single and multiple priority classes of traffic. We also compare its performance with other variations of DQDB.
On a MAC Protocol Based on Distributed Cycles
Authors: Dobosiewicz Włodek , Gburzyński Pawel
Published: December 2019

This paper introduces a novel transmission scheduling scheme applicable to high-speed ring networks. The essence of the proposed scheme is a special marker, called the terminator, circulating in the ring. The maximum normalised throughput, of our protocol does not degrade with the increasing propagation length of the ring and the stations endure small access delays under light load. Our protocol also offers a full-scale isochronous service without any need for fixed reservations, negotiations, or other preparatory stages.
Analysis of one-way reservation algorithms
Authors: Cidon Israel , Rom Raphael , Shavitt Yuval
Published: December 2019

Modern high speed networks (and ATM networks in particular) use resource reservation as a basic means of establishing communications. One-way on-the-fly reservation is a method for allocating resources for short bursts of data when regular reservation is too costly. The first of such algorithms were recently suggested by Turner. We investigate two examples that are characteristic to the way traffic streams interact in virtual circuit networks: a three node subnetwork that also acts as a 4X2 switch and a ring. For both systems we compute system throughput under homogeneous load, and compare it with the throughput when fast reservation protocols (FRP) are used. For the three node subnetwork we give an explicit expression for an upper bound.
A round robin medium access protocol for MANs
Authors: Bissonauth Ashvanee , Kamal Ahmed E.
Published: December 2019

In this paper, we introduce a new protocol, which we refer to as the R2-Net protocol. The objective of this proposal is to introduce an access protocol that is based on allowing active nodes to share the bandwidth in a round robin manner. By following such an approach, it is shown that the protocol does not suffer from the problems inherent in the DQDB protocol. The implementation of the round robin principle requires nodes to keep track of the number of active downstream nodes. In addition, and in order to overcome the adverse effects of the nonzero propagation delay, the total number of segments that must be transmitted by downstream nodes is also recorded. The protocol has several attractive features such as fairness in bandwidth distribution among nodes, a speedy convergence to such a distribution, a low access delay, and more importantly, insensitivity of such measures to node activity patterns. A simulation study has shown the satisfaction of such properties. Since priority is an important feature of every protocol, we also show how the R2-Net protocol can be generalized to implement priority.
An information-theoretic bound for the capacity of multihop lightwave networks with non-uniform traffic patterns
Authors: Acampora Anthony S. , Guo Duanyang
Published: December 2019

Multihop lightwave networks have recently emerged as prominent candidates for high-speed local, metropolitan, and wide-area networks. Of interest is the end-user capacity which may be afforded by a multihop lightwave network. For uniform traffic patterns, and for certain regular connection graphs, it is possible to compute the expected number of hops taken by a representative packet, the total network capacity, and the capacity available to each end-user. When the traffic patterns are non-uniform, simple expressions for network capacity cannot be produced.

In this paper, we apply information theoretic concepts to find an upper bound on the capacity which may be produced, by any multihop network, for an arbitrary non-uniform user-to-user traffic pattern. Also produced is a lower bound for the expected number of hops. Such bounds are useful as yardsticks against which the performance of specific architectures and connection graphs may be compared, since the methodology does not produce an multihop connection graph capable of achieving the bound. Although the work was stimulated by an interest in multihop lightwave networks, the bounds are equally applicable when non-uniform traffic is presented to any type of network involving packet switching nodes and directed connectivity graphs. Somewhat surprisingly, results obtained suggest that, for certain types of traffic non-uniformity, the capacity achievable per end user does not diminish as the number of network access stations increases.
A performance comparison of cell-based local area networks
Authors: Hassanein Hossam S. , Kamal Ahmed E. , Friesen Vema J.
Published: December 2019

Recently, the deployment of Asynchronous Transfer Mode (ATM) technology in the Local area (ATM LANs) has received much attention. Such interest is motivated by the simplifications offered in supporting ATM in the local area, which may result in rapid deployment of ATM-based Broadband Integrated Services Digital Networks (B-ISDN). Cell-based LANs, viz. ATM LANs, provide efficient bandwidth utilization and error recovery, as well as simplified priority implementation. We compare the performance of three cell-based LAN alternatives: the Distributed Queue Dual bus (DQDB) [1], Asynchronous Transfer Mode Ring (ATMR) [2] and switch-based ATM LANs employing ATM switches [3]. We develop a versatile simulation model which is used to study the merits of each alternative.
An efficient network architecture motivated by application-level QoS
Authors: Xie Geoffrey G. , Lam Simon S.
Published: December 2019

We consider application-level quality of service (QoS) requirements in design of networks that provide delay and loss guarantees. Using this approach, we have designed a novel network architecture that in many aspects is more efficient than ones motivated exclusively by packet QoS. An overview of our work is presented in this paper. The centerpiece of our design is a traffic model that enables delivery of application specific information to the network. Based on the traffic model, we have developed: (i) efficient network techniques for providing application-level delay guarantees, (ii) an admission control algorithm for a statistical service that bounds application data losses below a specified value, and (iii) network techniques for managing application data losses to achieve fairness and protection of high priority data units marked by applications (e.g., I frames of MPEG applications).
A fair slot routing solution for scalability in all-optical packet switched networks
Authors: Chlamtac Imrich , Elek Viktória , Fumagalli Andrea
Published: December 2019

The concept of Photonic Slot Routing (PSR) was recently proposed by the authors for providing scalability in WDM packet switching networks. PSR circumvents the fundamental problem of complexity of extant optical technologies when trying to use fast, wavelength selective switches to obtain all-optical packet switching. In a PSR network, wavelength sensitive information (i.e., optical packets) is handled by simplified routers which make use of wavelength non-sensitive devices, based on proven technology, to switch a set of packets on distinct wavelengths as a single unit, termed the photonic slot.

While leading to a practically simple router architecture, the all-optical PSR based network must also achieve a fair bandwidth allocation and deal with the contention that may arise at the router between photonic slots that arrive in different input fibers. The paper shows how the above objectives can be met by combining a fixed capacity assignment control with the PSR concept, thus achieving a bandwidth transparent, scalable and fair packet switching network with contention-free transmissions.
TCP over ATM: Performance results from a testing site
Authors: Sciuto Agatino
Published: December 2019

Because Transmission Control Protocol (TCP) is widely used to reliably transport data, there is considerable interest in its performance over Asynchronous Transfer Mode (ATM). Much research has been done in this area and results are available, mainly from computer simulations. However, simulation results do not contain the steps required by the user to optimize TCP performance. Nascom needed that information. This paper addresses different tests. It uses each test summary as an example for a specific issue. The summaries include configuration, results, and comments. The hardware and software used also are listed.

Based on NASA Communications (Nascom) test results, this paper shows that existing router implementations degrade TCP over ATM performance, that unspecified bit rate (UBR) is preferred over variable bit rate (VBR) for a traffic contract, and that multiple streams fairly share one ATM network.
Edge overlay multicast to support comparable multi-class services
Authors: Li Suogang , Xu Ke , Liu Ying , Wu Jianping
Published: December 2019

Traditional IP multicast is likely to imply a huge burden of storage and forwarding for routers. Some issues, such as the scalability problem, will be aggravated when various classes of quality of service are fulfilled in multicast traffic. The recent proposed application layer multicast is more scalable but increases traffic load in network layers and end-to-end delivery delay. In this paper, we present a multicast protocol that supports comparable multi-class services over an overlay network where edge routers are multicast-aware and core routers are oblivious of multicast. The comparable multi-class services consist of different services required by multicast members which can be satisfied via the same delivery tree. Considering the multi-class services and resource limitation on routers, the problem of building minimum cost trees has been proven to be NP-hard. So, we design several feasible heuristic algorithms to solve it. Extensive simulations are conducted to evaluate the performance of the proposed heuristics, and validate the effectiveness of reducing the total tree cost and iteration times under considered constraints. The proposed method is expected to be combined with DiffServ or MPLS VPN networks to fulfill multi-class QoS overlay multicast.
A uniform process alternator for arbitrary topologies
Authors: Haddix Furman , Peng Wuxu
Published: December 2019

We introduce an alternator with uniform processes that executes in a process graph of arbitrary topology. In general, alternators are free from deadlock, protect against simultaneous execution of the critical sections of dependent processes, and after a finite number of executions provide a high degree of concurrency and some degree of fairness (deterministically or stochastically). Because this alternator has uniform processes, strong fairness and concurrency are properties obtained after a finite number of steps with an arbitrary probability, due to the possibility of symmetry in states. The size of the state space and the periodicity of critical section execution are dependent upon the initial state. The worst case size of the state space utilized and period between critical sections executions depend upon the diameter of the graph of processes. An important value of alternators is their capacity for transforming systems correct under serial (interleaving) semantics to systems correct under concurrent or maximal (power set) semantics. This property is based upon a graph of processes representing the alternator in which the vertices are processes and the edges are dependencies between processes.
Enhancement of packet reordering in a mobile stream control transmission protocol for a heterogeneous wireless network vertical handover
Authors: Hamza Bashar J. , Ng Chee Kyun , Noordin N.K. , Rasid M.F.A. , Ismail A. , Tahir Yaseen H.
Published: December 2019

Future wireless access networks will be heterogeneous wireless network (HWN) environment which consists of various wireless technologies including universal mobile telecommunications system (UMTS) networks and wireless local area networks (WLAN). They are used together through vertical handover (VHO) to ensure global mobility and service continuity. The mobile stream control transmission protocol (mSCTP) layer supports dynamic association reconfiguration. This protocol allows mSCTP endpoints to dynamically add, change and delete IP addresses when the mobile node (MN) is switched between HWNs. During a mSCTP handover, the endpoints of the mSCTP are required to change the primary link from an old link to a UMTS into a new link to a WLAN. However, due to the disparity between UMTS/WLAN bandwidth, a packet reordering problem will occur when the MN of the mSCTP leaves to a new network. This packet reordering problem can then causes additional drawbacks such as impossibility of growing an mSCTP congestion window, unnecessary fast retransmissions, actual packet losses, and reduced efficiency of the receiving mSCTP. In this paper, we propose a packet reordering model (PRM) that is inserted inside the MN, and works as a special buffer of a large capacity with one input and one output port to receive all transmission sequence numbers (TSNs). It then forwards all incoming data chunks to the MN/WLAN networks after the VHO. The performance of the system is simulated and analyzed using NS-2 simulation tool. The simulation results show that the suggested model enhances the performance throughput and the congestion window of the conventional mSCTP through VHO by handling the packet reordering problem. In other words, the average performance throughout of the proposed PRM scheme is 181.48 Kbps or 16% increment compared to conventional mSCTP at 165.54 Kbps.
Availability study of M:N automatic protection switching scheme in WDM networks
Authors: Azim Mohamed Mostafa A. , Kabir Muhammad Nomani
Published: December 2019

Evaluation of the availability and unavailability of optical connections is necessary for WDM optical networks to make efficient use of optical resources. Network providers will not be welling to upgrade their current protection plans unless these protection strategies are carefully investigated, providing them with optimal tradeoffs between the required protection degree and the corresponding cost. In this paper, a mathematical model based on the combinatorial and probability theories is developed to evaluate the availability and unavailability of protected optical connections in WDM networks employing M:N dedicated protection. This model works with any number of working and protected paths. Several numerical tests have been performed and their results are presented to investigate the availability and unavailability degrees for different number of working and protection paths. Moreover, we use Monte-Carlo simulation to verify the correctness of our mathematical model. Simulation results confirm not only the correctness of the proposed model but also its potential accuracy. The proposed analytical model provides an efficient tool for network providers to assess the anticipated improvement in the network availability by upgrading their survivability schemes to higher protection classes.
A network scheme for TCP elastic traffic with admission control using edge-to-edge per-aggregate measurements in class-based networks
Authors: Fàbrega Lluís , Jové Teodor , Vilà Pere , Marzo José L.
Published: December 2019

We propose a network scheme with Admission Control (AC) for TCP flows, which can provide different minimum throughputs and isolation between flows. It is built with simple mechanisms without per-flow state, per flow signaling or per-flow processing in the core. The whole scheme uses a small set of packet classes, with a different discarding priority assigned to each one. The AC is implicit, edge-to-edge and based on per-aggregate throughput measurements. The out packets of the aggregation of accepted flows (i.e., the packets that correspond to the flows' extra throughput) act as a probing flow to test if the throughput in the network path is enough to satisfy the flow's request. Then signaling packets carry the per-aggregate throughput measurement from the egress to the ingress, where the AC decision is made. Through simulation we show that the scheme guarantees the requested minimum throughput to accepted flows and achieves a good utilization of resources.
Load balanced reliable task scheduling algorithm for heterogeneous systems
Authors: Chitra P. , Rajaram R. , Venkatesh P.
Published: December 2019

In a heterogeneous system, processor and network failure are inevitable and can have adverse effect on the complex applications executing on the systems. To reduce the rate of these failures, matching and scheduling algorithms should take into account the objectives of minimizing schedule length (makespan) and reducing the probability of failure. Equitable distribution of workload over resources contributes in reducing the probability of failure. The Heterogeneous Earliest Finish Time (HEFT) algorithm has been proved as a performance effective task scheduling algorithm, addressing the objective of minimizing makespan. Reliable Dynamic Level Scheduling (RDLS) algorithm is a bi-objective scheduling algorithm that maximizes the reliability more effectively. Though the reliable version of HEFT algorithm (RHEFT) considers failure rate in scheduling decision, the improvement in reliability is less, compared to that of RDLS. To overcome this deficiency, we propose to incorporate the task–processor pair finding step of RDLS in HEFT algorithm, since it meets both the objectives of minimizing the makespan and maximizing the reliability. We define the load on a processor as the amount of time the processor is engaged in completing the scheduled subtasks. In this paper, a modification to the HEFT is proposed as a new algorithm called Improved Reliable HEFT (IRHEFT) for minimizing the schedule length, balancing the load and maximizing the reliability of schedule. The algorithm is compared for its performance with RDLS algorithm for randomly generated task graphs and a real application task graph.
Active flows in diagnostic of troubleshooting on backbone links
Authors: Sukhov A.M. , Sidelnikov D.I. , Platonov A.P. , Strizhov M.V. , Galtsev A.A.
Published: December 2019

In this paper, we propose a novel approach to finding and predicting anomalous network states based on a flow monitoring mechanism. We assume that number of active flows can show a real network state. Moreover, the dependence between flow number and link utilisation allows us to derive an equation for the confidence interval on high-loaded network links. Experiments have been conducted that confirmed the basic position of the model and identified the anomaly network states. A software package based on this model has been created that allows the prevention of DDoS attacks. For successful operation of this software the number of active flows that single IP address can generate has been analysed.
Improving throughput in WiMAX communication at vehicular speeds
Authors: Ahmad Iftekhar , Habibi Daryoush
Published: December 2019

WiMAX technology has emerged as an exciting technology for next generation broadband wireless network with promises to offer high throughput and long coverage. WiMAX, however, has yet to prove its merits when the wireless nodes are not fixed and move at high vehicular speeds. Recent studies suggest that WiMAX offers limited throughput when a mobile node travels at vehicular speeds. Multipath fading causes high bit error rates at the receiver and is considered the main reason behind low throughput at high vehicular speeds. Bit error rates and maximum packet size govern the packet error rates, and error recovery for higher number of corrupted packets is not an attractive option for many real-time applications with tight delay and jitter constraints. In this paper, we present a mathematical model for estimating bit error rates in WiMAX communication at vehicular speeds. The estimated bit error probability is taken into account for proactively computing an optimum packet size that offers the best chance of achieving improved throughput. We further propose a model that can be used to increase the utility of real-time wireless applications (e.g., video surveillance systems in public train) based on the knowledge of estimated transmission rates. We simulated the proposed and other standard schemes for a centralized video surveillance system in a public train where the train moves at high speeds and sends real-time video data to a central control room through wireless channels. The results show that the proposed scheme achieves significantly higher throughput, lower jitter and higher utility gain compared to the standard schemes.
Performance analysis of LTE multiuser flat downlink power spectrum and radio resources scheduling
Authors: Abuhaija Belal
Published: December 2019

Long Term Evolution (LTE) technology is becoming the de-facto NGN mobile access network. In order to deliver multimedia contents and services, higher data rates and low latency is required. The new planned LTE base stations can deliver on high data throughput at lower latency than available cellular networks. However, this deployment comes at an increased complexity of radio resources scheduling and power allocations. More than one half of the network operating cost comes from electrical energy. Therefore, one aim of the network operators is to reduce cellular networks power consumption. In this paper, a simulation study of three proposed scheduling algorithms are studied under base station flat power spectrum constraints. LTE cell deployment is evaluated and analyzed to maximize cell throughput, while preventing cell edge customers from starvation. Studying the performance of flat cell power requirements, cell coverage, resource scheduling and maximum throughput is another aim of this paper. Average service mean time is a concept we introduce as a measure of the system efficiency.
Behr's Syndrome is Typically Associated with Disturbed Mitochondrial Translation and Mutations in the C12orf65 Gene
Authors: Pyle Angela , Ramesh Venkateswaran , Bartsakoulia Marina , Boczonadi Veronika , Gomez-Duran Aurora , Herczegfalvi Agnes , Blakely Emma L. , Smertenko Tania , Duff Jennifer , Eglon Gail , Moore David , Yu Wai Man Patrick , Douroudis Konstantinos , Santibanez-Koref Mauro , Griffin Helen , Lochmüller Hanns , Karcagi Veronika , Taylor Robert W. , Chinnery Patrick F. , Horvath Rita
Published: December 2019

Background: Behr's syndrome is a classical phenotypic description of childhood-onset optic atrophy combined with various neurological symptoms, including ophthalmoparesis, nystagmus, spastic paraparesis, ataxia, peripheral neuropathy and learning difficulties. Objective: Here we describe 4 patients with the classical Behr's syndrome phenotype from 3 unrelated families who carry homozygous nonsense mutations in the C12orf65 gene encoding a protein involved in mitochondrial translation. Methods: Whole exome sequencing was performed in genomic DNA and oxygen consumption was measured in patient cell lines. Results: We detected 2 different homozygous C12orf65 nonsense mutations in 4 patients with a homogeneous clinical presentation matching the historical description of Behr's syndrome. The first symptom in all patients was childhood-onset optic atrophy, followed by spastic paraparesis, distal weakness, motor neuropathy and ophthalmoparesis. Conclusions: We think that C12orf65 mutations are more frequent than previously suggested and screening of this gene should be considered not only in patients with mitochondrial respiratory chain deficiencies, but also in inherited peripheral neuropathies, spastic paraplegias and ataxias, especially with pre-existing optic atrophy.
Cognitive Deficits Associated with Sleep Apnea in Myotonic Dystrophy Type 1
Authors: Gallais Benjamin , Gagnon Cynthia , Mathieu Jean , Richer Louis , Jean Stéphane , Laberge Luc
Published: December 2019

Although sleep-disordered breathing and cognitive impairment are common features of patients with myotonic dystrophy type 1 (DM1), little is known about their relationship. Forty-three adult DM1 patients underwent 2 sequential polysomnographic sessions and a neuropsychological test battery (intellectual functioning, attention, language, memory, and executive functions). Lower scores in attention, vigilance, and executive functioning tests were associated with higher number of apneic/hypopneic episodes per hour of sleep and longer total sleep time at an oxyhemoglobin saturation of less than 90%. Results suggest a potential role for nighttime breathing problems in the cognitive impairment often observed in DM1 patients.
DM1 Patients with Small CTG Expansions are also at Risk of Severe Conduction Abnormalities
Authors: Denicourt Maxime , Pham Minh Trang , Mathieu Jean , Breton Robert
Published: December 2019

Background and Objectives: A high risk of cardiac arrhythmias was reported in myotonic dystrophy type 1 (DM1). The purpose of the study was to evaluate the risk of severe electrocardiographic abnormalities in DM1 patients with small CTG expansions. Methods: We assessed the ECG done at DM1 diagnosis for 127 patients with ≤200 CTG repeats and for 82 of them who had ≥1 ECG over a period of follow-up of 11.7 ± 7.6 years (mean ± SD). Criteria of severe ECG abnormality are at least one of the following features: PR interval ≥240 msec, QRS duration ≥120 msec, second-degree or third-degree atrioventricular block, atrial fibrillation or flutter, insertion of a pacemaker or cardioverter-defibrillator. Results: At baseline, ECG was normal for 109 patients out of 127 (85.8%) and only 4 patients (3.1%) presented severe ECG abnormalities. At follow-up, 46 patients out of 82 (56.1%) had a normal ECG and 25 (30.5%) developed severe ECG abnormalities (p < 0.0001) including 6 of them who needed permanent pacemaker insertion. There were also 3 sudden deaths during the follow-up period. Using multivariate Cox regression analysis, age at entry (relative risk RR, 1.05; (95% CI 1.01–1.08; p = 0.012) and muscular weakness (MIRS) at the entry (RR, 2.03; 95% CI 1.28–3.22; p = 0.003) were significant risk factors for the development of severe ECG abnormality. Conclusions: An increased risk of severe ECG abnormalitiesy and cardiac events is observed even in DM1 patients with small CTG expansions and warrants close cardiac follow-up similar to DM1 patients with larger CTG expansions.
Integrin dysregulation as a possible driver of matrix remodeling in Laminin-deficient congenital muscular dystrophy (MDC1A)
Authors: Accorsi Anthony , Mehuron Thomas , Kumar Ajay , Rhee Younghwa , Girgenrath Mahasweta
Published: December 2019

Background: Merosin-deficient congenital muscular dystrophy (MDC1A) is caused by a loss of Laminin-α2. Secondary manifestations include failed regeneration, inflammation, and fibrosis; however, specific pathomechanisms remain unknown. Objectives: Using the LAMA2DyW (DyW) mouse model of MDC1A, we sought to determine if Integrin-αV and -α5, known drivers of pathology in other diseases, are dysregulated in dystrophic muscle. Additionally, we investigated whether Losartan, a drug previously shown to be antifibrotic in dystrophic scenarios, rescues integrin overexpression in DyW mice. Methods: qRT-PCR, ELISA, and immunohistochemistry were utilized to characterize integrin and matricellular protein dysregulation in hind limb muscles from WT and untreated/ Losartan-treated DyW mice. Results: Integrin-αV and –α5 are significantly upregulated on both gene and protein level in DyW muscle- Losartan treatment attenuates this dysregulation. Immunohistochemistry showed that Integrin-αV is expressed on both infiltrating cells as well as on muscle cells- Losartan attenuates expression in both compartments. In addition, transcriptional overexpression of common matricellular and beta binding partners is rescued close to WT levels with Losartan. Lastly, latent and active TGF-β are upregulated in the serum of DyW mice, but only active TGF-β levels are attenuated by Losartan treatment. Conclusions: Our results suggest that overexpression of Integrin-αV and –α5 are likely contributing to secondary pathologies in MDC1A. We also believe that downregulation of Integrin-αV could be partially responsible for Losartan's antifibrotic effect and therefore could serve as a novel therapeutic target in MDC1A and other degenerative fibrotic diseases.
Diagnostic Utility of Auto-Antibodies in Inflammatory Muscle Diseases
Authors: Allenbach Y. , Benveniste O.
Published: December 2019

To date, there are four main groups of idiopathic inflammatory myopathies (IIM): polymyositis (PM), dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM) and sporadic inclusion body myositis; based on clinical presentation and muscle pathology. Nevertheless, important phenotypical differences (either muscular and/or extra-muscular manifestations) within a group persist. In recent years, the titration of different myositis-specific (or associated) auto-antibodies as a diagnostic tool has increased. This is an important step forward since it may facilitate, at a viable cost, the differential diagnosis between IIM and other myopathies. We have now routine access to assays for the detection of different antibodies. For example, IMNM are related to the presence of anti-SRP or anti-HMGCR. PM is associated with anti-synthetase antibodies (anti-Jo-1, PL-7, PL-12, OJ, and EJ) and DM with anti-Mi-2, anti-SAE, anti-TIF-1-γ and anti-NXP2 (both associated with cancer) or anti-MDA5 antibodies (associated with interstitial lung disease). Today, over 30 myositis specific and associated antibodies have been characterised, and all groups of myositis may present one of those auto-antibodies. Most of them allow identification of homogenous patient groups, more precisely than the classical international classifications of myositis. This implies that classification criteria could be modified accordingly, since these auto-antibodies delineate groups of patients suffering from myositis with consistent clinical phenotype (muscular and extra-muscular manifestations), common prognostic (cancer association, presence of interstitial lung disease, mortality and risk of relapse) and treatment responses. Nevertheless, since numerous auto-antibodies have been recently characterised, the exact prevalence of myositis specific antibodies remains to be documented, and research of new auto-antibodies in the remaining seronegative group is still needed.
Excessive Daytime Sleepiness in Patients with Myasthenia Gravis
Authors: Kassardjian C.D. , Kokokyi S. , Barnett C. , Jewell D. , Bril V. , Murray B.J. , Katzberg H.D.
Published: December 2019

Excessive daytime sleepiness (EDS) has not been investigated using objective tests in myasthenia gravis (MG). We investigated whether objective measurements of somnolence better detected abnormalities compared with sleepiness questionnaires in MG, and determine if MG patients have EDS. Eight patients with mild-to-moderate MG were recruited. Patients completed maintenance of wakefulness, overnight polysomnography, multiple sleep latency tests, Epworth Sleepiness Scale, and fatigue questionnaires. Seven patients demonstrated EDS on objective testing, while Epworth scores were abnormal in two, and the measures showed poor correlation. Our findings highlight that the ESS may be inadequate to diagnose EDS and lead to under-reporting of daytime somnolence in patients with MG.
Palivizumab and respiratory syncytial virus disease: Selling sickness for future?
Authors: Yudina Ekaterina V. , Ziganshina Liliya E.
Published: December 2019

Over the past two decades Russia has gone through dramatic “democratic” changes resulting in unprecedented deterioration of health, loss of lives and extinction of population. The health system turned into a ridiculous monster of poorly organized business exploiting reminiscent social values of the past to build profits on selling sickness-for-all in consumer culture. We present facts and conclude that introduction of palivizumab into clinical practice for the most vulnerable patient category was done without confirmation of efficacy, without pharmacoeconomics evaluations, without any precautionary measures in a country with undeveloped pharmacovigilance system. The situation calls for immediate action of responsible authorities and the society as a whole.
Births and male:female birth ratio in Scandinavia and the United Kingdom after the Windscale fire of October 1957
Authors: Grech Victor
Published: December 2019

AIMS: The Windscale (UK) fire of 1957 carried radioactive fallout according to the then prevailing wind patterns, in a North-Easterly direction across the Nordic countries, toward Norway. The male:female ratio at birth (M/F) is known to be increased after parental exposure to ionising radiation due to foetal losses that affect female more than male pregnancies. This study was carried out in order to ascertain whether the Windscale fire had any effects on M/F and birth rates in the United Kingdom and Scandinavia. METHODS: Annual live births by gender were obtained from a World Health Organization dataset. The null hypothesis was that there were no significant changes in M/F or in births in temporal association with the 1957 Windscale event in abovementioned countries. RESULTS: There were no significant effects on the UK and most of Scandinavia but there was a significant rise in M/F for Norway and Finland with an aggregate deficit of around 4000 births in each country. CONCLUSIONS: A recent study suggests that the plume from the reactor extended further east than previously believed. This study confirms that contamination from the Windscale fire had a negligible impact on the UK (as measured by birth effects) but had a significant impact on births in Norway and Sweden.