DQRAP (Distributed Queueing Random Access Protocol) is a random multiple access protocol for a slotted broadcast channel, shared by an infinite number of stations with bursty traffic, which can achieve a performance approaching that of a hypothetical perfect scheduling protocol (i.e. M/D/1 system). The Free Access DQRAP (FADQRAP) is an easy-to-implement version of DQRAP. FADQRAP, as does DQRAP,...

This paper examines the constraints that mediate the ability of individuals in developing country contexts to benefit from Information and Communication Technologies (ICTs). We identify social constraints, such as low levels of education and literacy rates, as making it difficult to access ICTs. We outline an innovative approach to address these constraints with a text free user interface (UI) ...

The TRIPS Agreement of the World Trade Organization (WTO) mandated the introduction of protection of intellectual property rights, notably patents, for pharmaceutical products. While the implications for the access to medicines contained in the terms of this Agreement raised significant concerns, a recent new wave of free trade agreements, negotiated outside the WTO, requires even higher levels...

The paper presents a novel static algorithm for mapping values to multiple register les. The algorithm is based on the edge-coloring of a bipartite graph. It allows the migration of values among the register les to keep the number of RAMs as small as possible. By comparison with the register le design used in the Cydra 5 mini-supercomputer, our approach substantially reduces the number of RAMs....

Several Canadian producers have implemented an inexpensive free-access feeding system modeled on Finnish guidelines,18 using formic acid as a milk preservative. The system mimics natural suckling and permits group social behavior. It allows for accelerated growth and changes labor requirements for calf rearing. Anecdotally, producers report less clinical cases of diarrhea and use of drugs for r...

Concurrent access to shared data in preemptive multi-tasks environment and in multi-processors architecture have been subject of many works. Proposed solutions are commonly based on semaphores which have several drawbacks. For many cases, lock-free techniques constitute an alternate solution and avoid the disadvantages of semaphore based techniques. We present the principle of these lock-free t...

The specification of access control policies for large, multi-organization applications is difficult and error-prone. Sophisticated policies are needed for fine-grained control of access to large numbers of entities, resulting in many policies specified by different security administrators. Techniques such as role based access control (RBAC) have been proposed to group policies and provide a fr...

By combining the features of CSMA and TDMA, fully decentralised WLAN MAC schemes have recently been proposed that converge to collision-free schedules. In this paper we describe a MAC with optimal long-run throughput that is almost decentralised. We then design two scheme that are practically realisable, decentralised approximations of this optimal scheme and operate with different amounts of s...

As a recently proposed public key primitive, attribute-based encryption (ABE) (including Ciphertext-policy ABE (CP-ABE) and Key-policy ABE (KP-ABE)) is a highly promising tool for secure fine-grained access control. For the purpose of secure access control, there is, however, still one critical functionality missing in the existing ABE schemes, which is the prevention of key abuse. In particula...

In this paper, we propose Hashing Backoff, an access method in which stations select backoff values by means of asymptotically orthogonal hashing functions, so that contending stations converge to a collision-free state. This solution is a half-way between TDMA, CDMA, and random access. Our simulations show that it presents significant improvement over Idle Sense, the access method with much be...