José M. Pousada-Carballo

Bluetooth-assisted context-awareness in educational data networks

In this paper, we propose an auxiliary location network, to support user-independent context-awareness in educational data networks; for example, to help visitors in a museum. We assume that, in such scenarios, there exist service servers that need to be aware of user location in real-time. Specifically, we propose the implementation of a Bluetooth Location Network (BLN). The BLN is composed of small wireless nodes, which establish an spontaneous network topology at system initialization, and interact with Bluetooth-enabled user terminals (WLAN or GPRS PDAs, or WAP phones) or independent Bluetooth modems (badges). The BLN may coexist with any data protocol (IP over IEEE 802.11b or GPRS, WAP). We do not impose specialized terminal programming for location purposes, since we rely on basic Bluetooth signaling (responses to inquiry cycles). We evaluate BLN feasibility in two real educational scenarios, a school and a museum.

A Java/CORBA virtual machine architecture for remote execution of optimization solvers in heterogeneous networks

Virtual machines for remote execution are a useful tool for utilizing light user interfaces and intensive application cores in different physical machines connected through the Internet. In a virtual machine, application cores are distributed in a network. Specific locations, operating systems and hardware characteristics are hidden by virtual machines. They make it possible to use a PC to execute user interfaces and (a few) high‐performance computers for application cores.

Fast image recovery using dynamic load balancing in parallel architectures, by means of incomplete projections

This paper formulates an incomplete projection algorithm that is applied to the image recovery problem. The algorithm allows an easy implementation of dynamic load balancing for parallel architectures. Furthermore, the local computation-communication load ratio can be adjusted, since each processor performs a finite number of iterations of any projection-type technique, and this number can be provided as a parameter of the algorithm. Numerical results compare favorably with those obtained by the extrapolated method of parallel subgradient projections.

Cellular Network for Real-Time Mobile Auction

Auctions are an ancient form of economic activity and, as such, have evolvedwith technology. However, some forms of traditional auction have survived unchanged, even inareas of great economic interest, until modern regulations imposed a change. We present thedesign of a specialized cellular network that has recently replaced traditional fishauctions in Galicia (Spain).

An Undergraduate Low-Level Computer Communications Laboratory Oriented towards Industry

This paper describes an educational methodology that we have implemented at the Universidad de Vigo which is based on a real competitive environment. It involves developing a communication subsystem, specified by a standard. Intercommunication between subsystems must take place successfully according to that standard. However, students are free to incorporate new features, enhance others, or optimize aspects which are roughly described.

Low-cost stabilized platform for airborne sensor positioning

We present a low-cost design of a stabilized platform to position sensors in aerial vehicles. The stabilization system has been designed to provide enough precision for vehicles flying at an altitude of <2000 m and a speed of <400 km/h. The design comprises a 3-axis accelerometer/gyroscope kit, an embedded controller (executing a Kalman filter and a postprocessing smoothing algorithm) and a kit of 3-axis orthogonally mounted high-torque servos.

On the application of formal description techniques to the design of interception systems for GSM mobile terminals

In this paper we show how a formal approach to design may speed up the development process for a new standard-based product: an interception device for GSM networks. We discuss the benefits, the limitations, and the lessons learnt using this approach, based on our own practical experience. A software package containing the results of this work and related documentation is freely available for academic institutions.

Improving Management Performance of P2PSIP for Mobile Sensing in Wireless Overlays

Future wireless communications are heading towards an all-Internet Protocol (all-IP) design, and will rely on the Session Initiation Protocol (SIP) to manage services, such as voice over IP (VoIP). The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P) technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT) and dSIP