. This paper studies the usage of broadcast communication in distributed services. The approach taken is practical: all the algorithms are asynchronous, and tolerate realistic faults. We study four problems in a broadcast domain: clock synchronization, reliable and ordered broadcast, membership

This paper presents the construction of a multicast service, called agreed multicast, that guarantees that messages arrive reliably and in the same total-order to all their destinations. ToTo, a novel family of protocols, implement the agreed multicast service of Transis, a communication sub-system for the High Availability project, currently developed at the Hebrew University of Jerusalem. This service is desired in distributed systems, and supports high level coordination among groups of processes in distributed applications. The ToTo protocols are genuinely symmetric. They are fairly simple and do not bear a significant processing burden. The cost of symmetric total ordering protocols can be measured by the number of messages from different machines needed to agree on the next set of messages to be delivered in total order. The ToTo protocols provide early delivery latency, and require as little as n 2 messages for delivery. Thus, we optimize the time that elapses from the point ...

The availability of small inexpensive sensor elements enables the employment of large wired or wireless sensor networks for feeding control systems. Unfortunately, the need to transmit a large number of sensor measurements over a network negatively affects the timing parameters of the control loop. This paper presents a solution to this problem by representing sensor measurements with an approximate representation--- an interpolation of sensor measurements as a function of space coordinates. A priority-based medium access control (MAC) protocol is used to select the sensor messages with high information content. Thus, the information from a large number of sensor measurements is conveyed within a few messages. This approach greatly reduces the time for obtaining a snapshot of the environment state and therefore supports the real-time requirements of feedback control loops.

not be suitable for underwater use. We consider how to time schedule each link in a broadcast domain once. We show that, unlike its terrestrial RF counterpart, this problem is NP complete. We then use a complete SAT solver to investigate the relation between the schedule length and the satisfiability of a given

We propose a wireless medium access control (MAC) protocol that provides static-priority scheduling of messages in a guaranteed collision-free manner. Our protocol supports multiple broadcast domains, resolves the wireless hidden node problem and allows for parallel transmissions across a mesh

The identification of near-duplicate keyframe (NDK) pairs is a useful task for a variety of applications such as news story threading and content-based video search. In this paper, we propose a novel approach for the discovery and tracking of NDK pairs and threads in the broadcast domain

deteriorate under such conditions. This paper reports on the design, construction, and experimental analysis of DiSCo, a German corpus for the evaluation of speech and speaker recognition on challenging material from the broadcast domain. One of the key requirements for the design of this corpus was a good

single broadcast domain. We show that, unlike its terrestrial RF counterpart, this problem is NP-complete, and the hard-to-approximate ratio is presented. Due to the intractability and inflexibility of centralized scheduling policies, and the high communication energy overhead of reservation

Existing programming enwronments for clusters are typically built on top of a point-to-point coremunica- hon layer (send and receive) over local area networks (LANs) and, as a result. suffer from poor performance m the collective commumcahon part, For ezample, a broadcast that is implemented usin a

and of processor failures and joins. The contribution of this paper is in providing an aggregate definition of communication and control services over broadcast domains. The main benefit is the efficient implementation of these services using the broadcast capability. In addition, the membership algorithm has a