Abstract
When accessing and interacting with regular electronic devices or informatics systems, users frequently depend on the sight sense because the information is, consistently, presented in a visual format, despite the feasibility to use additional formats, such as audio. It also happens that the access to the information systems is triggered by the action of the users, hence requiring an awareness of the surrounding environment. These two facts lead to an exclusion of a considerable number of citizens, such as the visually impaired ones, from a fair access to the so-called Information Society. The development of automatic user-aware Interactive Voice Response (IVR) systems can be an interesting solution to this issue, particularly, if the communications are done in a private manner and a low-cost implementation is achieved. In a reply to this challenge, it was formulated a pervasive user detection and communication concept, based on Bluetooth technology and Linux software modules, allowing improved interaction between the personal area information systems and the mobile user devices. To demonstrate the validity of the concept, it was developed a personal area IVR system, based on Linux, being the interaction with the users made by means of the Bluetooth technology.

Abstract

Abstract
This paper analyzes experimentally the limitations observed in lightwave systems using distributed Raman amplifiers operating under large pump power input conditions. The Brillouin effect is observed as the pump power becomes equal to watt centered in a specific pump wavelength. The presence of Brillouin peaks degrades the system performance. The Raman amplifier is set with singlemode and dispersion compensating fibers and evaluated in a high capacity WDM link at transmission rates up to 40 Gb/s per channel. The dispersion compensation was accomplished by adjusting the length of the dispersion compensating fiber. The system and amplifier characterization were developed in terms of the on-off gain, ripple, optical signal-to-noise ratio, eye diagram and extinction ratio.

Abstract
In this paper, two printed multiband fractal monopole antennas using the 1(st) and 2(nd) iteration of Minkowski Island geometry are proposed for WLAN communications. The monopole antennas have compact size of 28 x 18 mm(2) and 21.5 x 18 mm(2), respectively. The proposed antennas with different sizes of the ground plane have also been studied through numerical simulations in Ansoft HFSS. It is found that without using any impedance matching method, both of the proposed antennas exhibit good impedance match at both 2.4 and 5.2 GHz band, which is confirmed by the measurement results. It is also observed that the monopole antenna with the geometry of the 1(st) iteration Minkowslci Island can also operate at 3.5 and 5.8 GHz, which means that it almost covers the entire required frequency bands for 802.11a/b/g and WiMAX communications. The simulation shows that both antennas exhibit high radiation efficiency and the measured radiation patterns show that both antennas have similar radiation patterns at each resonant frequency.

Abstract
We assess the performance of a coherent optical system employing a phase estimation algorithm combined with a least mean square decision-directed equalizer in a feedback configuration and compare it to the constant modulus algorithm with an independent carrier phase estimation approach for 16-quadratic-amplitude-modulation transmission. Both series and parallel implementations are discussed. Hardware issues regarding a recursive implementation of the estimation filter are also reported.

Abstract
The options to implement a coherent optical system employing a phase estimation algorithm combined with adaptive linear equalization are investigated. Several carrier phase estimator strategies are discussed, in terms of parallelization, performance and implementation complexity.