Today’s distributed information systems often are collections of existing information sources and as such heterogeneous. Technical integration of heterogeneous sources is supported by CORBA [2]. However, CORBA provides very general support, and does not take source specific semantics into account. This also applies to CORBA’s Event Service. Our objective is to enhance CORBA by mechanisms that a...

In this paper, we consider a discrete-time single-server finite-buffer batch arrival queue in which customers are served in batches according to a general bulk-service rule, that is, at least ‘a’ customers are needed to start a service with a maximum serving capacity of ‘b’ customers. The server takes a (single and multiple) vacation as soon as the queue length falls below ‘a’ at the completion...

Recently, the software industry has published several proposals for transactional processing in the Web service world. Even though most proposals support arbitrary transaction models, there exists no standardized way to describe such models. This paper describes potential impacts and use cases of utilizing advanced transaction meta-models in the Web service world and introduces a suitable meta-...

Snap rounding is a method for converting arbitrary-precision arrangements of segments into fixed-precision representation. We present an algorithm for snap rounding with running time O((n + I) log n), where I is the number of intersections between the input segments. In the worst case, our algorithm is an order of magnitude more efficient than the best previously known algorithms. We also propo...

We give algorithms for the computation of the d-th digit of certain transcendental numbers in various bases. These algorithms can be easily implemented (multiple precision arithmetic is not needed), require virtually no memory, and feature run times that scale nearly linearly with the order of the digit desired. They make it feasible to compute, for example, the billionth binary digit of log (2...

Speedup measures how much faster we can solve the same problem using many cores. If we can afford to keep the execution time fixed, then quality up measures how much better the solution will be computed using many cores. In this paper we describe our multithreaded implementation to track one solution path defined by a polynomial homotopy. Limiting quality to accuracy and confusing accuracy with...

We study the method of bounding the spectral gap of a reversible Markov chain by establishing canonical paths between the states. We provide examples where improved bounds can be obtained by allowing variable length functions on the edges. We give a simple heuristic for computing good length functions. Further generalization using multicommodity ow yields a bound which is an invariant of the Ma...

  Response time is one of the critical web service quality dimensions. It refers to how long it takes that a web service responds to request of a user. In order to manage the response time, pricing schemes can work as an efficient access control mechanism. In this paper, we study competition between two providers offering functionally same web services where there is a monopoly service provider...

Example 1 Consider a queue where customers arrive one by one. There is a single server that serves each customer on a first-come-first-served basis. Define the sojourn time experienced by a customer as the time he/she spends in the system: waiting (if any) for service plus the duration of the service at the server. The server toggles between being idle for some time when there are no customers ...

In integrated services networks, the provision of Quality of Service (QoS) guarantees depends critically upon the scheduling algorithm employed at the network layer. In this work we review fundamental results on scheduling, and we focus on Packet Fair Queueing (PFQ) algorithms, which have been proposed for QoS wirelinewireless networking. The basic notion in PFQ is that the bandwidth allocated ...