Performance analysis of bit error rate for free space optical communication with tip-tilt compensation based on gamma-gamma distribution

In this paper, the gamma-gamma probability distribution is used to model turbulent channels. The bit error rate (BER) performance of free space optical (FSO) communication systems employing on-off keying (OOK) or subcarrier binary phase-shift keying (BPSK) modulation format is derived. A tip-tilt adaptive optics system is also incorporated with a FSO system using the above modulation formats. The tip-tilt compensation can alleviate effects of atmospheric turbulence and thereby improve the BER performance. The improvement is different for different turbulence strengths and modulation formats. In addition, the BER performance of communication systems employing subcarrier BPSK modulation is much better than that of compatible systems employing OOK modulation with or without tip-tilt compensation.

Del boceto al objeto a través del BIT en la obra "La materia del tiempo", de Richard Serra

423 p.

Linking transformational leadership and organizational trust: has organizational commitment a mediating effect on it?

[EN] The main goal of this study is to analyze how organizational commitment has a mediating effect on the relation between transformational leadership and organizational trust. Therefore we developed an organization analysis based on a survey that was used to collect primary data from a sample of 58 employees. We obtained a 71% response rate and these data were analyzed using quantitative methodological techniques and linear regression. The research was conducted at the Serralves Foundation (Porto, Portugal) to empirically test the proposed research model and its hypotheses. The empirical results confirm that transformational leadership positively enhances organizational trust. However, transformational leadership and organizational trust are not significantly influenced by organizational commitment, thus not having a mediating effect on this relationship. Such results assume particular relevance because they become a basis for comparative studies in similar organizations. This study brings some theoretical contributions to the literature by analyzing the mediating effect of organizational commitment on the relation between transformational leadership and organizational trust in cultural organizations and has also some practical management implications, as it draws attention to the importance of a set of practices, job satisfaction oriented, which can effectively lead to organizational commitment intervention in the relationship between transformational leadership and organizational trust.