Diversity techniques for blind channel equalization in mobile communications

A blind algorithm for channel distortion compensation is presented which can be employed in spatial or temporal diversity receivers. The proposed technique can be used in frequency selective and frequency flat fading mobile channels, using burst transmission schemes in the first case and OFDM modulation in the second one. The algorithm is base on a deterministic criteria and is suited for estimation when short sets of data are available.Peer ReviewedPostprint (published version

Transform modulations for mobile communications

A new modulation scheme called transform modulations is proposed which improves the system performance in frequency-flat fading mobile channels. They ameliorate the effect of the fadings over the transmitted signal by spreading the information in time, using a linear transform operator. The design of this scheme is discussed and its advantages are shown by means of simulations. The relationship of this scheme with OFDM modulation is also analyzed.Peer ReviewedPostprint (published version

The Teacher: another Variable in the Use of Foreign Language Learning Strategies?

The Bologna process aims to create the European Higher Education Framework (EHEF) by making academic degree and quality assurance standards more comparable and compatible throughout Europe. The EHEF has different implications for university students, representing a change in emphasis from ‘teaching’ to ‘learning’, from a teacher-centred approach to a student-centred approach. In the last thirty years, researchers have discussed the role of teachers and students in the language learning-teaching process. Until then, the acquisition of a foreign language was focused on the teacher’s methodology. In the 80s and 90s, a series of student-centred approaches emerged, with the aim of making students more autonomous and independent in their learning. Language learning strategies are part of the tools used to improve language learning. There are different definitions and taxonomies of language learning strategies (Chamot (2001), Cohen (1998), Oxford (1990), O'Malley (1990) and Wenden & Rubin (1987) and there have been extensive descriptive studies on the different variables affecting the use of learning strategies including gender, previous linguistic knowledge, motivation, learning styles and/or second language versus foreign language acquisition. This paper aims to explore the instructor’s conscious or unconscious influence students’ use of learning strategies. To undertake this study, a group of teachers was asked to assess the 50 strategies presented in an adapted version of the Strategies Inventory Language Learning (Oxford 1990) according to their suitability and practicality for their students. The participants were lecturers from the French and English Department at Cádiz University. The languages included in the study were English, French and German for specific and general purposes

The trade-offs of social assistance programs in the labor market: The case of the “Seguro Popular” program in Mexico

In 2002, the Mexican government began a tremendous financial effort to provide health insurance, Seguro Popular (SP), to the 50 million uninsured in Mexico. In doing so, the states and municipalities offered virtually free health insurance to uncovered self-employed and informal salaried workers substantially altering the incentives for workers and firms to operate in the formal economy. We take advantage of the staggered implementation of the program across municipalities to estimate the effects of the SP in the labor market. We find that the SP had a negative effect in the creation of formal jobs, especially in small and medium sized firms. According to our estimates, had the program not been in place, 31.000 more employers and 300.000 new formal jobs should have been registered with Mexican social security. These represent 3.8% and 2.4% of the stock of registered employers and employees in 2002 when the program started.social assistance program, informality, labor market, Mexico