Data path synthesis in digital electronics. I. Memory allocation

A data path consists of memory elements (i.e., registers), data operators (i.e. ALUs) and interconnection units (i.e. buses) to control the data transfers in the digital system. Many approaches to hardware allocation for data path synthesis have been proposed in the literature; however, only single-port memory is considered for register allocation and no efficient synthesis approach for multiport memory synthesis. A novel design methodology for data path synthesis using multiport memories is proposed which can be applied to hardware allocation algorithms or to already synthesized data path as a postprocessor to achieve a better design. Illustrations of applying this method to different synthesis examples are presented. Results and improvements over previous techniques are demonstrated. Experiments on benchmarks show very promising results     

Optimal radar threshold determination in Weibull clutter andGaussian noise

A technique is presented for determining the ideal detection threshold when Gaussian noise and Weibull distributed clutter returns are present on a radar receiver and neither is dominant. Quantitative data is presented for several clutter types and false alarm probabilities     

Mutual coupling effects and their reduction in wideband directionof arrival estimation

The performance of multiple signal classification (MUSIC) algorithm using three different inputs over a wideband of frequencies is considered. These inputs are: 1) ideal voltages, 2) actual voltages which include coupling effects and are obtained with the method or moments, and 3) corrected voltages which are obtained from the actual voltages so that the mutual coupling effects are removed. Linear arrays of dipoles, sleeve dipoles, and spiral antennas are considered over 200 MHz to 400 MHz band     

Some do's and don't's for young EE's or advice I wish I'd had whenI started

The author outlines several rules for starting electrical engineers that he developed during his career. The rules are divided into general rules, rules for career growth, and job-related rules     

Partial pressures and nature of products. Application to the photolysis of PH3 and NH3 in the atmosphere of Jupiter and Saturn.

The photolysis of mixtures of gases containing NH3 or PH3 presents important differences mainly due to the strength of the X-H bond. On some examples, these differences are evidenced and the consequences for mixtures of gases containing these two compounds are shown: the photolysis of ammonia and ethylene mainly gives ethyl-, butyl- and hexylamine whereas the photolysis of phosphine and ethylene leads to ethyl- and vinylphosphine. When gaseous mixtures of NH3, PH3 and ethylene are photolyzed together, the presence of phosphine dramatically decreases the formation of nitrogen derivatives. The relevance of such lab studies to the atmospheres of Jupiter and Saturn is discussed.     

Infrared spectrometer PFS for the Mars 94 orbiter

Thin films containing a mixture of aliphatic (glycine) and aromatic (tryptophan or tyrosine) amino acids were exposed to a vacuum ultraviolet radiation (VUV) with wavelenghts 100–200 nm. Dipeptides (glycyl-tryptophan and glycyl-tyrosine) were synthesized in these conditions. We compared the actions of VUV and γ-radiation. Polymerization is an essential step in prebiological evolution and we have shown that this stage probably occured over an early Solar system history.     

Heavy-ion induced genetic changes and evolution processes.

On Moon and Mars, there will be more galactic cosmic rays and higher radiation doses than on earth. Our experimental studies showed that heavy ion radiation can effectively cause mutation and chromosome aberrations and that high-LET heavy-ion induced mutants can be irreversible. Chromosome translocations and deletions are common in cells irradiated by heavy particles, and ionizing radiations are effective in causing hyperploidy. The importance of the genetic changes in the evolution of life is an interesting question. Through evolution, there is an increase of DNA content in cells from lower forms of life to higher organisms. The DNA content, however, reached a plateau in vertebrates. By increasing DNA content, there can be an increase of information in the cell. For a given DNA content, the quality of information can be changed by rearranging the DNA. Because radiation can cause hyperploidy, an increase of DNA content in cells, and can induce DNA rearrangement, it is likely that the evolution of life on Mars will be effected by its radiation environment. A simple analysis shows that the radiation level on Mars may cause a mutation frequency comparable to that of the spontaneous mutation rate on Earth. To the extent that mutation plays a role in adaptation, radiation alone on Mars may thus provide sufficient mutation for the evolution of life.     

High energy particle dispersion events observed by interball-1 and -2

Time period from October 1996 until January 1998 was checked on high energy resolution DOK2 energetic particle instrument measurements on Interball-1 and Interball-2 for the ion (> 20 keV) dispersive events (EDIS) with the exclusion of Interball-1 orbit parts in the tail. A variety of energy dispersive events, both in ion and electron spectra with different duration is found in the auroral regions, in the outer magnetosphere and near the cusp. While EDIS were observed in all sectors of MLT, the best conditions for their observation were in the afternoon local time. The characteristics of dispersive events observed by DOK2 are consistent with their explanation by the gradient-curvature drift of particles from the injection point(s) in the night local time sector given in Lutsenko at al., 2000a, b.     

The local interstellar medium viewed through pickup ions, recent results and future perspectives

Over the last 10 years the experimental basis for the study of the very local interstellar medium (VLISM) has been substantially broadened by the direct detection of pickup ions and of neutral helium. The strength of these methods lies in the local measurement of the particles. By scanning the gravitational focusing cone of the interstellar wind, a consistent set of interstellar helium parameters, neutral density, temperature and relative velocity, has been derived. However, the accuracy of these parameters is still hampered by uncertainties in some of the crucial ionization rates and in the pickup ion transport. Recent observations have shown that the scattering mean free path of pickup ions is comparable with the large scale variation of the interplanetary magnetic field (IMF) in the inner heliosphere. This requires a substantial modification in the modeling of the ion distribution and more detailed measurements, tasks that can be addressed in the near future.     

The Indian Space Program

The Indian Space Program is described. The main objectives of the program are to provide operation space services to the nation, especially in the fields of communications and remote sensing, and to use modern space technology for the benefit of the Indian people. Some applications of the Indian Space Program are remote sensing, imagery, communications, broadcasting, and surveys of natural resources for water, crop, forest, land, minerals, and ocean. The emphasis is on the development and operation of indigenous satellites and launch vehicles for providing these space services