Abstract
We show that incoherently coupled soliton pairs are possible in biased photorefractive crystals, under steady-state conditions. These solitons can propagate in bright-bright, dark-dark, as well as in bright-dark configurations. Such soliton pairs can be established provided that the carrier beams share the same polarization, wavelength, and are mutually incoherent. Relevant examples are provided where the photorefractive crystal is of the strontium barium niobate type. The characteristics and stability properties of these soliton states are also discussed in detail. © 1996 American Institute of Physics.

Abstract
The cross-correlation between i(DD) and v(out) signals is addressed as a means for improving the testing of analogue circuits. Besides the higher testing confidence provided by mixed i(DD)/v(out) monitoring, a single unified test operation is performed instead of two separate operations.

Abstract
The quality of low bit-rate coding algorithms standardized under ISO/MPEG has been carefully verified by subjective listening tests using audio material of the highest technical quality. When using digital audio compression in the context of television sound systems, however, the question arises, as to how the coders would perform with imperfect audio signals, such as those obtained from impaired film material. This paper describes studies into the effects of the more severe impairments present in film soundtracks upon MPEG-I Layer-2 and Layer-3 audio coding, which have been carried out within the European RACE `COUGAR' project programme R2122.

Abstract
Parallel systems are not necessarily special-purpose machines. Al present, most departmental servers already resort to shared memory multiprocessing as a means to increase performance, while a network of workstations can also be regarded as a distributed memory parallel system. This paper examines the support offered by the operating system to exploit such parallelism. After discussing the design of multi-threaded programs in a Unix environment, a comparison is made with their distributed counterparts. Some performance figures obtained on a SparcCenter 2000 multiprocessor, on a network of workstations and on a transputer-based system are presented.

Abstract
Three classes of oceanographic addressing relevant distinct scientific and applied objectives in the Portuguese coastal waters are examined. Then, by assuming some mission organizations in the light of the current technological state-of-art, a set of functionalities required for an operational system are extracted. Finally, some requirements for the design and development of such a class of systems are discussed.

Abstract