This report documents the results of a preliminary study on the application of various modulation and forward error control (FEC) techniques for application to wireless local area networks (WLAN) applications. The report considers the existing quadrature phase shift keying (QPSK) -Barker code based system. The notion of bandwidth and signal to noise ratios Es/No and Eb/No are reviewed. It is sh...

It has been a controversial issue in the research of cognitive science and artificial intelligence whether signal-type representations (typically connectionist networks) or symbol-type representations (e.g., semantic networks, production systems) should be used. Meanwhile, it has also been recognized that both types of information representations might exist in the human brain. In addition, sym...

This paper focuses on non-data aided estimation of the symbol rate and detecting the data symbols in linearly modulated signals. A blind oversampling-based signal detector under the circumstance of unknown symbol period is proposed. First, the symbol rate is estimated using the Expectation Maximization (EM) algorithm. However, within the framework of EM algorithm, it is difficult to obtain a cl...

An efficient and systematic LL(1) error recovery method is presented that has been implemented for an LL( 1) parser generator. Error messages which provide good diagnostic information are generated automatically. Error correction is done by discarding some input symbols and popping up some symbols from the parsing-stack in order to restore the parser to a valid configuration. Thus, symbol delet...

We present a joint symbol, frame, and carrier synchronization method for the Eureka 147 DAB signal in this paper. Symbol timing is determined first by detecting an abrupt change in the phase angle of the complex product between the last quarter of a useful symbol and its cyclic extension in the guard interval. The detection of this abrupt change is based on the maximal likelihood (ML) principle...

In general, an n-ary predicate (relation) describes the relationship among its arguments, and such that no argument has to be of a special mode. The uniication and the resolution (SLDNF-resolution) do capture this state of aaair. Hence, the aim of logic programming is in some point approximatively achieved if the system is able to automatically determine the descriptive mode of an n-ary predica...

Approved for public release; distribution is unlimited. Reducing the clutter on geographical displays should help military decision-makers manage their attention and concentrate on the most important or threatening tracks. This report presents a study that considered the question of how the decluttered tracks should be represented. The declutter symbols must simultaneously reduce distraction wh...

This paper looks at capacity achieving detection strategies for information transfer over time-varying channels. The time-varying binary symmetric channel (TV-BSC) is identified as the basic binary state-space model. Separation of entropies principles and the TV-BSC model-based state-space approach are used to determine the performance bounds for coherent and non-coherent detection over time-va...