Rich scattering of electromagnetic waves propagating through physical environments generates complex interference patterns. As such patterns go through maxima and minima, large variations in energy adversely affect wireless reception and thus deteriorate error probability performance of wireless communication systems. By providing multiple channels with independent (or at least uncorrelated) va...

We study the consequences of introducing individual nonconformity in social interactions, based on Axelrod’s model for the dissemination of culture. A constraint on the number of situations in which interaction may take place is introduced in order to lift the unavoidable homogeneity present in the final configurations arising in Axelrod’s related models. The inclusion of this constraint leads ...

A high degree of topical diversity is often considered to be an important characteristic of interesting text documents. A recent proposal for measuring topical diversity identifies three elements for assessing diversity: words, topics, and documents as collections of words. Topic models play a central role in this approach. Using standard topic models for measuring diversity of documents is sub...

This document explains diversity related methods in vegan. The methods are briefly described, and the equations used them are given often in more detail than in their help pages. The methods discussed include common diversity indices and rarefaction, families of diversity indices, species abundance models, species accumulation models and beta diversity, extrapolated richness and probability of ...

Downlink transmit diversity modes for WCDMA together with a two fixed-beam antenna array system are compared relative to the single antenna sectorized system in a radio network simulator. The transmit diversity methods investigated are: space time transmit diversity and closed loop mode I transmit diversity. Frequency selective (COST 259) and flat fading channels are considered and their impact...

Similar to direct sequence code division multiple access (DS-CDMA), site diversity can be applied to a multicarrier-CDMA (MCCDMA) cellular system to improve the bit error rate (BER) performance for a user with weak received signal power, thus resulting in an increased link capacity. In this paper, the downlink site diversity reception using frequency-domain equalization based on minimum mean sq...

Orthogonal multicode direct sequence code division multiple access (DS-CDMA) has a flexibility in offering various data rate services. However, in a frequency-selective fading channel, the bit error rate (BER) performance is severely degraded since othogonality among spreading codes is partially lost. In this paper, we apply frequency-domain equalization and antenna diversity combining, used in...

Habitat distribution and seasonal occurrence of carabid beetles were determined using pitfall traps in 1999 and 2000 in the temperate forest zone of the Dongling Mountain, North China. Eight sites differing in vegetation and moisture were selected so as to represent four habitat types. Carabid assemblages of the six forested habitats (lowland, upland and coppice) were more similar to each other...