Aldelir Fernando Luiz

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  • Creighton T R Hager, Scott F Midkiff, Ezra A Brown, Luiz A Dasilva, Nathaniel J Davis, Thomas L Martin +14 others
  • 2004
(ABSTRACT) This research investigated methods to determine appropriate security protocols for specific wireless network applications. The specific problem being addressed was that there are tradeoffs between security, performance, and efficiency among current and proposed security protocols. Performance and efficiency issues are particularly important in(More)
An important aspect of wireless networks is their dynamic behavior. The conventional protocol stack is inflexible as various protocol layers communicate in a strict manner. In such a case the layers are designed to operate under the worst conditions as opposed to adapting to changing conditions. This leads to inefficient use of spectrum and energy.(More)
  • Vikram Dham, A Luiz, Dasilva, F Scott, Annamalai Midkiff, Annamalai +2 others
  • 2003
(Abstract) Traditionally medium access control protocols for ad hoc networks have been designed for nodes using omni directional antennas. Through the use of directional antennas, it is possible to obtain higher efficiency. In this thesis we investigate the impact of these antennas on aggregate throughput and end-to-end delay. The use of omni-directional(More)
—Transaction commit is a problem much investigated, both in the databases and systems communities, from the theoretical and practical sides. We present a modular approach to solve this problem in the context of database replication on environments that are subject to Byzantine faults. Our protocol builds on a total order multicast abstraction and is proven(More)
  • Michael S Thompson, Scott F Midkiff, A Luiz, Ing-Ray Dasilva, Chen, L Thomas +17 others
  • 2006
Service discovery is a driving force in realizing pervasive computing. It provides a way for users and services to locate and interact with other services in a pervasive computing environment. Unfortunately, current service discovery solutions do not capture the effects of the human or physical world and do not deal well with diverse device populations;(More)
Replication is often considered a cost-effective solution for building dependable systems with off-the-shelf hardware. Replication software is usually designed to tolerate crash faults, but Byzantine (or arbitrary) faults such as software bugs are well-known to affect transactional database management systems (DBMSs) as many other classes of software.(More)
  • Vivek R Srivastava, A Luiz, Dasilva, Robert P Gilles, Allen B Mackenzie, F Scott +9 others
  • 2008
A Mobile Ad Hoc Network (MANET) adopts a decentralized communication architecture which relies on cooperation among nodes at each layer of the protocol stack. Its reliance on cooperation for success and survival makes the ad hoc network particularly sensitive to variations in node behavior. Specifically, for functions such as routing, nodes which are(More)
  • Shakheela H Marikar, A Luiz, Jeffrey H Dasilva, Annamalai Reed, Annamalai, Ramesh Chembil Palat +4 others
  • 2002
(Abstract) Modern mobile communication systems will provide enhanced high-speed data, multimedia, and voice services to mobile users. The integration of such heterogeneous traffic types implies that the network must provide differentiated Quality of Service (QoS). Beam forming techniques have been proposed to increase the spectral efficiency of the wireless(More)
(Abstract) Asymmetric digital subscriber line (ADSL) is a broadband access technology capable of delivering large bandwidth over existing copper telephone line infrastructure. This research aims at characterizing and analyzing TCP/IP performance in presence of a new protocol stack (TCP/IP over PPP and ATM) being promoted for one of the ADSL network(More)
The purpose was to describe the main features of headache incidence in a hospital community, its frequency and the most requested medical investigation. Due to the stressful work environment, hospital is considered to hold a high-risk population. Interviews and questionnaires were utilized. Of a 1006 files, which were randomly filled out, 987 could be(More)