A Framework for Differential Frame-Based Matching Algorithms in Input-Queued Switches

This article is made available under terms and conditions applicable to Open Access Policy Articl

On the Stability of Isolated and Interconnected Input-Queued Switches under Multiclass Traffic

In this correspondence, we discuss the stability of scheduling algorithms for input-queueing (IQ) and combined input/output queueing (CIOQ) packet switches. First, we show that a wide class of IQ schedulers operating on multiple traffic classes can achieve 100 % throughput. Then, we address the problem of the maximum throughput achievable in a network of interconnected IQ switches and CIOQ switches loaded by multiclass traffic, and we devise some simple scheduling policies that guarantee 100 % throughput. Both the Lyapunov function methodology and the fluid modeling approach are used to obtain our results

Multiclass scheduling algorithms for the DAVID metro network

Abstract—The data and voice integration over dense wavelength-division-multiplexing (DAVID) project proposes a metro network architecture based on several wavelength-division-multiplexing (WDM) rings interconnected via a bufferless optical switch called Hub. The Hub provides a programmable interconnection among rings on the basis of the outcome of a scheduling algorithm. Nodes connected to rings groom traffic from Internet protocol routers and Ethernet switches and share ring resources. In this paper, we address the problem of designing efficient centralized scheduling algorithms for supporting multiclass traffic services in the DAVID metro network. Two traffic classes are considered: a best-effort class, and a high-priority class with bandwidth guarantees. We define the multiclass scheduling problem at the Hub considering two different node architectures: a simpler one that relies on a complete separation between transmission and reception resources (i.e., WDM channels) and a more complex one in which nodes fully share transmission and reception channels using an erasure stage to drop received packets, thereby allowing wavelength reuse. We propose both optimum and heuristic solutions, and evaluate their performance by simulation, showing that heuristic solutions exhibit a behavior very close to the optimum solution. Index Terms—Data and voice integration over dense wavelength-division multiplexing (DAVID), metropolitan area network, multiclass scheduling, optical ring, wavelength-division multiplexing (WDM). I

Stapled hemorrhoidopexy: no more a new technique

Haemorrhoidal disease affect between 4.4% and 36.4% of the general population. The common symptoms are: bleeding, prolapse, pain, discharge, itching and hampered anal hygiene. There is no correlation between specific symptoms and anatomic grading. Apparently severe looking haemorrhoids can cause relatively few symptoms. Open haemorrhoidectomy, as described by Milligan, has been accepted worldwide as the best choice for treatment of symptomatic haemorrhoids. In 1998, Longo proposed a procedure for haemorrhoidectomy with minimal postoperative pain, no perianal wound requiring postoperative wound care and a relatively short operative time. His technique presented a new notion for treating haemorrhoids as he proposed circumferential rectal mucosectomy that results in mucosal lifting (anopexy). His aim was not excision of the haemorrhoidal tissue but rather restoring anatomical and physiological aspects of the haemorrhoidal plexus. The grading system described by Goligher, is the most commonly used and is based on objective findings and patient history. Stapled hemorrhoidopexy is performed for grade III and IV, for grade II in case of major bleeding. In lithotomy position and spinal anesthesia and after taking all aseptic precautions, the procedure of stapled hemorrhoidectomy was performed according to Longo’s technique. After this surgical procedure, the need to manually reduce prolapse will have been cured in approximately 90% of patients and the overall preoperative symptoms will be much reduced in the great majority. There should be no anal pain. Bowel habits should have returned to a normal pattern without urgency. One year follow-up or longer 11% of patients had remaining or recurrent prolapse, the reintervention rate is about 10%

The VEI 2 Christmas 2018 Etna Eruption: A Small But Intense Eruptive Event or the Starting Phase of a Larger One?

The Etna flank eruption that started on 24 December 2018 lasted a few days and involved the opening of an eruptive fissure, accompanied by a seismic swarm and shallow earthquakes, significant SO2 flux release, and by large and widespread ground deformation, especially on the eastern flank of the volcano. Lava fountains and ash plumes from the uppermost eruptive fissure accompanied the opening stage, causing disruption to Catania International Airport, and were followed by a quiet lava effusion within the barren Valle del Bove depression until 27 December. This was the first flank eruption to occur at Etna in the last decade, during which eruptive activity was confined to the summit craters and resulted in lava fountains and lava flow output from the crater rims. In this paper, we used ground and satellite remote sensing techniques to describe the sequence of events, quantify the erupted volumes of lava, gas, and tephra, and assess volcanic hazards.Publishedid 9056V. Pericolosità vulcanica e contributi alla stima del rischioJCR Journa