Web resources, such as publications, datasets, pictures and others can be directly linked to their provenance data, as described in the specification about Provenance Access and Query (PROV-AQ) by the W3C. On its own, this approach places all responsibility with the publisher of the resource, who hopefully maintains and publishes provenance information. In reality, however, most publishers lack...

The importance for this tutorial is to introduce the students into the loss systems, and, to underline the difference between the concepts of call-blocking and time-blocking probabilities, and to understand under which conditions these probabilities are identical. The selected exercises introduce, also, the Erlang tables, which is an important tool for easy calculations for the blocking probabi...

We present QueueVadis, a system that addresses the problem of estimating, in real-time, the properties of queues at commonplace urban locations, such as coffee shops, taxi stands and movie theaters. Abjuring the use of any queuing-specific infrastructure sensors, QueueVadis uses participatory mobile sensing to detect both (i) the individual-level queuing episodes for any arbitrarily-shaped queu...

Definition Amessage is an information sent by a sender process to a receiver process. A message queue is a mechanism that allows a sender process and a receiver process to exchange messages; the sender posts a message in the queue, and the receiver retrieves the message from the queue. A message queuing system provides a mean to build distributed systems, where distributed processes communicate...

Fair-queuing schedulers provide clients with bandwidth or latency guarantees provided they are well-behaved i.e. the requested service is always within strict predefined limits. Violation of the service bounds results in nullification of the performance guarantees of the misbehaving client. In this paper we relax this notion of good behavior and present a generalized service model that takes th...

Packet scheduling constitutes the core problem in efficient fair allocation of bandwidth to competing flows. To date, numerous algorithms for packet scheduling have been suggested and tested. However, only a few of them are currently deployed. One of the key reasons for rarity of applied packet scheduling methods lies in the complexity of their implementation. This paper describes a family of r...

a r t i c l e i n f o During the course of a construction project, there are many situations in which formation of waiting lines or queues is inevitable. The effect of resource delays in queues on the overall project completion time and cost has motivated researchers to employ simulation for analysis of queuing systems in order to identify the best operational strategies to reduce the time wast...

We study an admissions control problem, where a queue with service rate 1 − p receives incoming jobs at rate λ ∈ (1 − p,1), and the decision maker is allowed to redirect away jobs up to a rate of p, with the objective of minimizing the time-average queue length. We show that the amount of information about the future has a significant impact on system performance, in the heavy-traffic regime. W...

In this paper, we present a new queueing algorithm for networks, called Hierarchical Fair Queueing (HFQ). This shares the bandwidth between classes of users, and (within each class) between subclasses. HFQ provides a guaranteed share of bandwidth to each class, but bandwidth is not wasted when a class is inactive. Unlike the Link Sharing scheme of Floyd-Jacobsen, HFQ is provably fair, in that t...