We analyze the asymptotic behavior of the Flow Deviation Method, first presented in 1971 by Fratta, Gerla and Kleinrock, and show that when applied to packing linear programs such as the maximum concurrent flow problem, it yields a fully polynomial-time approximation scheme.

The Nix operating system permit different roles to be assigned to the cores. One of the roles is able to run userspace code with no interrupts from the operating system, which is particularly useful for HPC. System calls are especially expensive to a core playing this role. This paper presents a new implementation of optimistic semaphores that avoids performing expensive system calls in an unco...

cycle multithreading. Eliminating this source of synchronization In this paper we describe a source of synchronization overhead by allowing synchronization to be used in places where its unique to multithreaded processors, and present a novel generaloverhead previously precluded its use. We give an example in purpose synchronization scheme that addresses this overhead. Section 2, after we intro...

Integrating concurrent and object-oriented language facilities is currently an active research area. There are a few experimental languages which attempt to combine various models of concurrency within an OOP framework. Most of these suffer from the so called inheritance anomaly where a concurrent object’s synchronisation code needs to be modijied if the object is extended. Ada 95 has avoided s...

It has been found that an algorithm can generate true random numbers on classical computer. The algorithm can be used to generate unbreakable message PIN (personal identification number) and password. Cryptography has long history [1]. Interestingly, it has been found that taking key material from open source it is possible to design unbreakable crypto-system. Following the technique [2] an alg...

Workkow Management Systems (WFMSs) automate the execution of business processes allowing the concurrent execution of multiple process instances. Existing systems do not provide a mechanism to guarantee correct concurrent execution and, as a result, it is not possible to coordinate and synchronize diierent process instances. Part of the problem is that conventional techniques are not entirely su...

Fall 2007: Assignment No. 3 Due Date: 12.21.07 December 10, 2007 The solution to this assignment should be submitted as attachment to an e-mail message. The textual part should be prepared as a postscript, PDF, or Word document. All submitted smv and pf files should be submitted as separate files. You may group all relevant files into a single file, using ZIP or TAR. 1 Peterson(N) Algorithm In ...

Nowadays 'optical communication' usually means the exchange of information with the aid of optical fibres. The term is also applicable, however, to visual communication by semaphore or similar methods. In France between 1793 and 1852, for example, a visual communication network designed by Claude Chappe was in use. This worked with a system of moving arms that could be viewed by telescope from ...

Computer control of discrete applications present a challenging dependability problem since any wrong output may lead the system to a completely anomalous state. This is in contrast with continuous feedback systems where wrong outputs can only gradually deviate the system under control from its intended set point. Transient errors may even be filtered by the latency inherent to the physical app...

Android is thought as being yet another operating system! In reality, it is a software platform rather than just an OS; in practical terms, it is an application framework on top of Linux, which facilitates its rapid deployment in many domains. Android was originally designed to be used in mobile computing applications, from handsets to tablets to e-books. But developers are also looking to empl...