Biljana Badic et al. 443 Since the publication of Alamouti’s famous space-time block code, various quasi-orthogonal space-time block codes (QSTBC) for multi-input multi-output (MIMO) fading channels for more than two transmit antennas have been proposed. It has been shown that these codes cannot achieve full diversity at full rate. In this paper, we present a simple feedback scheme for rich sca...

In evolutionary computation (EC), genetic diversity (or its absence) gets the credit (or the blame) for a multitude of effects — and so mutation operators, population initialization, and even pseudo-random number generators, all get probed and prodded to improve genetic diversity. This paper demonstrates how extra initial diversity can appear to cause improvements in the performance of coevolut...

Abstmct In th i s paper, we address the problem of characterizing the performance of space-time modulat i on in t ime-correlated fading environment. We show that the space-time signals of square size achieving full diversity in quasi-static fading channels can also achieve full diversity i n t ime-correlated fading channels, irrespectively of the t i m e correlation matr ix . We also generalize...

Clustered multi-hop wireless networks have attracted significant attention for their robustness to fading, hierarchical structure, and ability to exploit the broadcast nature of the wireless channel. The authors propose an opportunistic routing (or relay selection) algorithm for such networks. In contrast to the majority of existing approaches to routing in clustered networks, the algorithm pre...

Green space is important for the maintenance of the ecological dimension of a sustainable urban landscape. Therefore, in order to figure out the relationship between the greening of urban parks and bird diversity, we used 5 avian ecological diversity indexes, such as Species richness, Abundance, ShannonWeiner diversity index, Evenness, and Margalef’s richness indices, to evaluate the functional...

We consider multi-antenna systems employing space-time coding over quasi-static Rayleigh fading channels. We prove that by selecting a subset of the antennas t h a t observe the largest instantaneous signal-to-noise ratios (SNRs) at the receiver one can achieve the same diversity order as the full complexity system, provided that the sub-channels are independent and the underlying space-time co...

We introduce a new family of Space-Time Trellis Codes which extends the powerful characteristics of SuperOrthogonal Space-Time Trellis Codes to four transmit antennas. We consider a family of quasi-orthogonal space-time block codes as building blocks in our new trellis codes. These codes combine set-partitioning and a super set of quasi-orthogonal space-time block codes in a systematic way to p...

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 ...