Multiple representation of spatial data, which means obtaining different detailed representation of geographic phenomena based on the same spatial database or different data versions, is one of the key technologies for digital earth. It plays an important role in such applications as seamless data navigation, progressive web transfer and self-adaptable visualization. Multiple representation tec...

We show that manipulation and selection of optical patterns is possible by detuning the frequency of one of the two waves in counterpropagating photorefractive two-wave mixing with a feedback mirror. An analytical expression for the onset of modulational instability is derived for the general case of an arbitrary complex coupling constant, including a possible frequency shift of the generated s...

This paper presents a new sequential decoding algorithm based on dynamic searching strategy to improve decoding efficiency. The searching strategy is to exploit both sorting and path recording techniques. By means of sorting, we cun identify the correct path in a very fast way and then, by path recording, we can recover the bit sequence without degmding decoding performance. We also develop a c...

The winter-rainfall region of southern Africa, covered largely by the fynbos and succulent karoo biomes, harbours the world’s greatest concentration of geophyte species. Species diversity is greatest in the south-west, where more than 500 species co-occur in one quarter-degree square; in the south-east the values are generally around 100, and in the arid north-west, always less than 50 (more of...

The LONG TERM ECOLOGICAL RESEARCH program (L TEA) is a network of field sites used to study structure and process in natural landscapes at temporal and spatial scales of decades or centuries. The ten sites now funded by the National Science Foundation's Division of Biotic Systems and Resources, include forest, prairie, desert, and aquatic environments. Major questions are addressed at each site...

We present de Vaucouleurs’s effective radii in B and R bands for a sample of Molonglo Reference Catalogue radio galaxies and a control sample of normal galaxies. We use the ratio of the scale lengths in the two bands as an indicator in order to show that the radio galaxies tend to have an excess of blue color in their inner region much more frequently than the control galaxies do. We show that ...