Dealing with Heterogeneity in a Fully Reliable Multicast Protocol

Many of the proposed multicast congestion avoidance algorithms are single-rate where heterogeneity is accommodated by adjusting the transmission rate as a response to the worst receiver in the group. Due to the Internet heterogeneity, a single-rate congestion co ntrol affects the overall satisfaction of the receivers in a multicast session. In this paper, we propose a multi-rate replicated scheme where some receivers (instead of the source) are designated to perform data replication for other receivers with lower capacity. To be more scalable and to minimize the bandwidth consumption due to data replication, the partitioning algorithm is per- formed on-the-fly by the routers depending on the feedback they receive. Neither a prior estimation of the receivers capacity is necessary nor a complex computation is required to execute our partitioning algorithm

Dealing with Heterogeneity in an Active-based Multicast Congestion Avoidance Protocol

Many of the proposed multicast congestion avoidance algorithms are single-rate where heterogeneity is accommodated by adjusting the transmission rate as a response to the worst receiver in the group. Due to the Internet heterogeneity, a single-rate congestion control affects the overall satisfaction of a multicast session receivers. In this report, we propose a multi-rate replicated scheme where some receivers (instead of the source) are designated to perform data replication for other receivers with lower capacity. To be more scalable and to minimize the bandwidth consumption due to data replication, the partitioning algorithm is performed on-the-fly by the routers depending on the feedbacks they receive. Neither a prior estimation of the receivers capacity is necessary nor a complex computation is required to execute our partitioning algorithm

An Active Reliable Multicast Framework for the Grids

Computational Grids are foreseen to be one of the most critical yet challenging technologies to meet the exponentially growing demands for high-performance computing in a large variety of scientific disciplines. Most of these grid applications imply multiple participants and in many cases make an intensive usage of data distribution and collective opertaions. In this paper, we propose a multicast framework consisting of an active reliable protocol with specialized active services located at the edges of the core network for providing low-latency and low-overhead multicast transfers on computational grid

A RTT-based Partitioning Algorithm for a Multi-rate Reliable Multicast Protocol

Various Internet applications involve multiple parties and usually adopt a one-to-many communication paradigm (multicast). The presence of multiple re ceivers in a multicast session rises the problem of inte¡ r-receiver fairness. Transmitting with a rate which matches the slowest receiver will limit the throughput of other receivers and thus their satisfaction. A multi-rate mechanism where the receivers are distributed into subgroups with similar capacities, can improve the inter-receiver fairness for multicast sessions. In this paper, we deal with the problem of receivers partitioning and propose a simple algorithm based on the receivers RTT variations where an explicit estimation of the receivers capacities is avoided. Our partitioning algorithm, although simple, performs an on-the-fly partitioning depending on the receivers' feedback. We show that our partitioning algorithm approximates and in many cases, achieves the optimal solution with a minimum computation effort

Application of Liutex and Entropy Production to Analyze the Influence of Vortex Rope in the Francis-99 Turbine Draft Tube

The vortex structures in a draft tube of a Francis turbine are confused, primarily when cavitation occurs, which may induce severe vibration and noise. Understanding this vortex\u27s periodical precession and investigating the vortex rope influence in the draft tube cone is required for stable operation at off-design conditions. This study captured the cavitating flow with high accuracy by utilizing the SST turbulence and ZGB cavitation models. The Omega and Liutex methods are employed and compared with the traditional Q - criterion to determine the vortex rope behavior in the Francis-99 turbine draft tube. The result showed that the Liutex/Rortex method is advantageous over the Q - criterion for representing the vortex rope structure. The Liutex method can effectively remove the boundary layer\u27s influence on visual vortex structures from the draft tube\u27s wall. Moreover, the local hydraulic loss distribution was clarified by using entropy production. By comparing Liutex magnitude distribution and entropy production rate, the vortex rope behavior effects on local hydraulic loss were significantly illuminated

Design of a Configurable 4-Channel Analog Front-End for EEG Signal Acquisition on 180nm CMOS Process

In this work, a 4-channel Analog Front-End (AFE) circuit has been proposed for EEG signal recording. For EEG recording systems, the AFE may handle a wide range of sensor inputs with high input impedance, adjustable gain, low noise, and wide bandwidth. The buffer or current-to-voltage converter block (BCV), which can be set to operate as a buffer or a current-to-voltage converter circuit, is positioned between the electrode and the main amplifier stages of the AFE to achieve high input impedance and work with sensor signal types. A chopper capacitively-coupled instrumentation amplifier (CCIA) is positioned after the BCV as the main amplifier stage of the AFE to reduce input-referred noise and balance the impedance of the overall AFE system. A programmable gain amplifier (PGA) is the third stage of the AFE that allows the overall gain of the AFE to be adjusted. The suggested AFE operates in a wide frequency range of 0.5 Hz to 2 kHz with a high input impedance bigger than 2TΩ, and it is constructed and simulated using a 180nm CMOS process. With the lowest 100-dB CMRR and low input-referred noise of 1.8 µVrms, the AFE can achieve low noise efficiency. EEG signals can be acquired with this AFE system, which is very useful for detecting epilepsy and seizures

A RTT-based Partitioning Algorithm for a Multi-rate Reliable Multicast Protocol

Various Internet applications involve multiple parties and usually adopt a one-to-many communication paradigm (multicast). The presence of multiple receivers in a multicast session rises the problem of inter-receiver fairness. Transmitting with a rate which matches the slowest receiver will limit the throughput of other receivers and thus their satisfaction. A multi-rate mechanism where the receivers are distributed into subgroups with similar capacities, can improve the inter-receiver fairness for multicast sessions. In this report, we deal with the problem of receivers partitioning and propose a simple algorithm based on the receivers RTT variations where an explicit estimation of the receivers capacities is avoided. Our partitionin- g algorithm, although simple, performs an on-the-fly partitioning depending on the receivers' feedback. We show that our partitioning algorithm approximates and in many cases, achieves the optimal solution with a minimum computation effort.Une grande variété d'applications impliquent la participation de plusieurs entités, ainsi un paradigme de communication one-to-many (multicast) y est le plus adapté. La présence de plusieurs récepteurs dans une session de multicast soulève le problème de l'équité inter-récepteurs. L'émission avec le débit du récepteur le plus lent limita sans doute la satisfaction des autres récepteurs; Un mécanisme multi-débit où les récepteurs sont partitionnés sur des sous-groupes de capacités similaires, pourrait améliorer considérablement l'équité inter-récepteur. dans ce rapport, nous traitons le problème du partitionnement des récepteurs et proposons un algorithme simple basé sur les variations du RTT des différents récepteurs. une estimation explicite des capacités des récepteurs est ainsi évitée. Notre algorithme de partitionnement fait un partitionnement à-la-volée en fonction des messages de contrôle provenant des récepteurs. on montre que l'algorithme proposé approche e dans plusieurs cas atteint la solution optimale avec une complexité minimal

A Loss Detection Service for Active Reliable Multicast Protocols

Reliable multicast protocols have gained popularity with active service contributions where routers implement additional functionalities. Reducing the delay of recovery is one of the desirable features of a reliable multicast protocol. In this paper we propose an active-based architecture with specialized routers. Using simulations we show how this architecture with the proposed services (mainly the loss recovery from the receivers and the loss detection at the routers), could improve the performances of a reliable multicast application in term of the recovery delay

Fast Forwarding with Network Processors

Forwarding is a mechanism found in many network operations. Although a regular workstation is able to perform forwarding operations it still suffers from poor performances when compared to dedicated hardware machines. In this paper we study the possibility of using Network Processors (NPs) to improve the capability of regular workstations to forward data. We present a simple model and an experimental study demonstrating that even though NPs are less powerful than Host Processors (HPs) they can forward data more efficiently than HPs in some specific cases