A virtual queue can be used to predict when a real queue is about to grow. This memo explains why using a leaky bucket to implement a virtual queue is not useful, despite a superficial similarity. However, it is possible to implement a useful virtual queue using two leaky buckets. It requires a simple trick that can typically be implemented with existing hardware.

A shaper is a system that stores incoming bits in a bu er and delivers them as early as possible, while forcing the output to be constrained with a given arrival curve. A shaper is time invariant if the tra c constraint is de ned by a xed arrival curve; it is time varying if the condition on the output is given by a time varying tra c contract. This occurs, for example, with renegotiable variab...

A broadband RF system has been built for the new Fermilab Recycler Ring. It is designed to both bunch and capture beam during transfers and create multiple, moveable RF barrier buckets for azimuthal control of the stored antiproton beam. Beam will be bunched and captured using bursts of four RF cycles at 2.5 MHz. To maximize bucket area, the multiple barrier buckets will be generated by pairs o...

Measuring topic quality is essential for scoring the learned topics and their subsequent use in Information Retrieval and Text classification. To measure quality of Latent Dirichlet Allocation (LDA) based topics learned from text, we propose a novel approach based on grouping of topic words into buckets (TBuckets). A single large bucket signifies a single coherent theme, in turn indicating high...

Histograms are summary structures of large datasets, which are mainly used for selectivity estimation during query optimization. Selectivity estimation is the fast approximation of query result size. In this paper, we focus on multi-dimensional histograms, especially bidimensional histograms. At the time of selectivity estimation, buckets partially overlapping with a query return approximated r...

Mini-Bucket Elimination (MBE) is a well-known approximation algorithm for graphical models. It relies on a procedure to partition a set of funtions, called bucket, into smaller subsets, called mini-buckets. The impact of the partition process on the quality of the bound computed has never been investigated before. We take first steps to address this issue by presenting a framework within which ...

A weighted constraint satisfaction problem (WCSP) is a constraint satisfaction problem in which preferences among solutions can be expressed. Bucket elimination is a complete technique commonly used to solve this kind of constraint satisfaction problem. When the memory required to apply bucket elimination is too high, a heuristic method based on it (denominated mini-buckets) can be used to calc...

You may recall from the previous lecture that the use of electro mechanical relays, and in subsequent years, diodes and transistor, made it possible to construct more advanced computers, e.g. ENIAC. This is accredited to the fact that these devices could function as on/off switches. On one hand, they create the ability to encode logic into the circuits of the computer. This means that the compu...

‘THEUSE of heavy aluminum foil in our ashing procedure for PB1 (1), introduced 3 years ago, has proved extremely successful in preventing cross-contamination. A Temco double-door muffle furnace is used for which three steel buckets were made; small buckets, 4 in. wide, 6 in. long, and 6 in. deep, and one large bucket, 6 in. wide, 8 in. long, and 6 in. deep. A steel shovel was made to aid the te...

Traffic shaping and smoothing using buffers or leaky buckets does not necessarily improve Quality of Service (QoS). In fact there is a trade-off between controlling user traffic and guaranteeing QoS to the users. We consider the first two stages (source node and border node before entering a network cloud) of an end-to-end QoS problem and assume that the QoS requirements across each of the two ...