D-MG Tradeoff and Optimal Codes for a Class of AF and DF Cooperative Communication Protocols

Cooperative relay communication in a fading channel environment under the orthogonal amplify-and-forward (OAF), non-orthogonal and orthogonal selection decode-and-forward (NSDF and OSDF) protocols is considered here. The diversity-multiplexing gain tradeoff (DMT) of the three protocols is determined and DMT-optimal distributed space-time code constructions are provided. The codes constructed are sphere decodable and in some instances incur minimum possible delay. Included in our results is the perhaps surprising finding that the OAF and NAF protocols have identical DMT when the time durations of the broadcast and cooperative phases are optimally chosen to suit the respective protocol. Two variants of the NSDF protocol are considered: fixed-NSDF and variable-NSDF protocol. In the variable-NSDF protocol, the fraction of time occupied by the broadcast phase is allowed to vary with multiplexing gain. In the two-relay case, the variable-NSDF protocol is shown to improve on the DMT of the best previously-known static protocol for higher values of multiplexing gain. Our results also establish that the fixed-NSDF protocol has a better DMT than the NAF protocol for any number of relays.

Accurate performance analysis of single and opportunistic AF relay cooperation with imperfect cascaded channel estimates

Given the significant gains that relay-based cooperation promises, the practical problems of acquisition of channel state information (CSI) and the characterization and optimization of performance with imperfect CSI are receiving increasing attention. We develop novel and accurate expressions for the symbol error probability (SEP) for fixed-gain amplify-and-forward relaying when the destination acquires CSI using the time-efficient cascaded channel estimation (CCE) protocol. The CCE protocol saves time by making the destination directly estimate the product of the source-relay and relay-destination channel gains. For a single relay system, we first develop a novel SEP expression and a tight SEP upper bound. We then similarly analyze an opportunistic multi-relay system, in which both selection and coherent demodulation use imperfect estimates. A distinctive aspect of our approach is the use of as few simplifying approximations as possible, which results in new results that are accurate at signal-to-noise-ratios as low as 1 dB for single and multi-relay systems. Using insights gleaned from an asymptotic analysis, we also present a simple, closed-form, nearly-optimal solution for allocation of energy between pilot and data symbols at the source and relay(s).

Novel Relay Selection Rules for Average Interference-Constrained Cognitive AF Relay Networks

Cooperative relaying combined with selection exploits spatial diversity to significantly improve the performance of interference-constrained secondary users in an underlay cognitive radio (CR) network. However, unlike conventional relaying, the state of the links between the relay and the primary receiver affects the choice of the relay. Further, while the optimal amplify-and-forward (AF) relay selection rule for underlay CR is well understood for the peak interference-constraint, this is not so for the less conservative average interference constraint. For the latter, we present three novel AF relay selection (RS) rules, namely, symbol error probability (SEP)-optimal, inverse-of-affine (IOA), and linear rules. We analyze the SEPs of the IOA and linear rules and also develop a novel, accurate approximation technique for analyzing the performance of AF relays. Extensive numerical results show that all the three rules outperform several RS rules proposed in the literature and generalize the conventional AF RS rule.

Ativismo judicial : o Supremo Tribunal Federal estaria legislando? Caso dos mandados de injunção que regulamentam o direito de greve dos servidores públicos

Analisa o fenômeno do ativismo judicial com a postura do Supremo Tribunal Federal nos julgamentos de mandados de injunção sobre o direito de greve dos servidores públicos. Para tal, demonstrar-se-ão os conceitos de Poder, principalmente do Poder Político e Judiciário, ativismo judicial, a questão da separação dos Poderes e os efeitos jurídicos do mandado de injunção decorrentes da atuação do Supremo, destacando sua mudança de posicionamento em 2007. É esta alteração de sua jurisprudência o objeto central deste trabalho, com o intuito de se verificar se o ativismo judicial praticado no âmbito do Supremo Tribunal Federal, nessa ocasião, o levou a legislar, exercendo o ativismo judicial e interferindo em função precípua do Poder Legislativo.

Les Portugais d'Amérique : souvenirs historiques de la guerre du Brésil en 1635 : contenant un tableau intéressant des moeurs et usages des tribus sauvages, des détails instructifs sur la situation des colons dans cette partie du nouveau-monde : ouvrage destiné a la jeunesse

Illustré de 12 dessins impremés en 2 couleurs

Technical efficiency in artisanal fisheries (AF) in Badagry local government area of Lagos State, Nigeria

This study examined the technical efficiency in artisanal fisheries in Lagos State of Nigeria. The study employed a two stage random sampling procedure for the selection of 120 respondents. The analytical techniques involved descriptive statistics and estimation of technical efficiency following maximum likelihood estimation (MLE) procedure available in FRONTIER 4.1. The MLE result of the stochastic frontier production function showed that hired labour, cost of repair and capital items are critical factors that influences productivity of artisanal fishermen with the coefficient of hired labour being highly elastic. This implies that employing more labour will significantly increase the catch in the study area. The predicted farm efficiency with an average value of 0.92 showed that there is a marginal potential of about 8 percent to increase the catch, hence the income of the fishermen. The study further examined the factors that influence productivity of fishermen in the study area. Year of education, mode of operation and frequency of fishing have important implication on the technical efficiency of fishermen in the study area.

Genom Norra Amerikas Fèorenta Stater. Reseskildringar af P. Waldenstrèom.

http://www.archive.org/details/genomnorramer00waldrich

[Book review] Reviews. [1] Nicholas Crane, Mercator: The Man Who Mapped the Planet, London: Weidenfield and Nicolson, 2002. [2] Stephen Inwood: The Man Who Knew Too Much: The Strange and Inventive Life of Robert Hooke (1635-1703), London: Macmillan, 2002

Book reviews of: [1] Nicholas Crane, Mercator: The Man Who Mapped the Planet, London: Weidenfield and Nicolson, 2002, £20, ISBN: 0297646656. [2] Stephen Inwood: The Man Who Knew Too Much: The Strange and Inventive Life of Robert Hooke (1635-1703), London: Macmillan, 2002, £18.99, ISBN: 0333782860.

Expedited Solid-Phase Synthesis of Fluorescently Labeled and Biotinylated Aminoalkane Diphenyl Phosphonate Affinity Probes for Chymotrypsin- and Elastase-Like Serine Proteases

In this study, we report on a novel, expedited solid-phase approach for the synthesis of biotinylated and fluorescently tagged irreversible affinity based probes for the chymotrypsin and elastase-like serine proteases. The novel solid-phase biotinylation or fluorescent labeling of the aminoalkane diphenyl phosphonate warhead using commercially available Biotin-PEG-NovaTag or EDANS NovaTag resin permits rapid, facile synthesis of these reagents. We demonstrate the kinetic evaluation and utilization of a number of these irreversible inactivators for chymotrypsin-like (chymotrypsin/human cathepsin G) and elastase-like serine proteases. Encouragingly, these compounds display comparable potency against their target proteases as their N-benzyloxycarbonyl (Cbz)-protected parent compounds, from which they were derived, and function as efficient active site-directed inactivators of their target proteases. We subsequently applied the biotinylated reagents for the sensitive detection of protease species via Western blot, showing that the inactivation of the protease was specifically mediated through the active site serine. Furthermore, we also demonstrate the successful detection of serine protease species with the fluorescently labeled derivatives “in-gel”, thus avoiding the need for downstream Western blotting. Finally, we also show the utility of biotinylated and pegylated affinity probes for the isolation/enrichment of serine protease species, via capture with immobilized streptavidin, and their subsequent identification via de novo sequencing. Given their selectivity of action against the serine proteases, we believe that these reagents can be exploited for the direct, rapid, and selective identification of these enzymes from biological milieu containing multiple protease subclasses.

On the Study of Network Coded AF Transmission Protocol for Wireless Multiple Access Channels

In this paper, the performance of the network coded amplify-forward cooperative protocol is studied. The use of network coding can suppress the bandwidth resource consumed by relay transmission, and hence increase the spectral efficiency of cooperative diversity. A distributed strategy of relay selection is applied to the cooperative scheme, which can reduce system overhead and also facilitate the development of the explicit expressions of information metrics, such as outage probability and ergodic capacity. Both analytical and numerical results demonstrate that the proposed protocol can achieve large ergodic capacity and full diversity gain simultaneously.

Tracing Inspiration in Proverbial Material: From 'The Royal Dictionary' (1699 & 1729) of Abel Boyer to 'The English-Irish Dictionary' (1732) of Begley-McCurtin.

This metalexicographic study examines the relationship between the proverbial material in The English-Irish Dictionary (1732) of Begley and McCurtin, Abel Boyer’s The Royal Dictionary (First edition 1699, second edition 1729), and Nathaniel Bailey’s An Universal Etymological English Dictionary (1721). It will show, for the first time, that both the English macrostructure and microstructure of the proverbial entries in Begley and McCurtin (1732) were reproduced directly from Boyer’s dictionary and, in spite of claims to the contrary, the impact of Bailey’s (1721) dictionary was negligible. Furthermore, empirical data gleaned from a comparative linguistic analysis of the various editions of The Royal Dictionary prior to 1732, will prove that it was the second official edition (1729) that was used as the framework for The English-Irish Dictionary. A quantitative and qualitative analysis of the nature of the proverbial entries will also outline the various translation strategies that were used to compose the Irish material— particularly literal translation—and show that there are extremely high-levels of borrowings from Boyer (1729), both in terms of the English entries under the lemma, and the French entries in the comment.

Generic Ergodic Capacity Bounds for Fixed-Gain AF Dual-Hop Relaying Systems

This paper elaborates on the ergodic capacity of fixed-gain amplify-and-forward (AF) dual-hop systems, which have recently attracted considerable research and industry interest. In particular, two novel capacity bounds that allow for fast and efficient computation and apply for nonidentically distributed hops are derived. More importantly, they are generic since they apply to a wide range of popular fading channel models. Specifically, the proposed upper bound applies to Nakagami-m, Weibull, and generalized-K fading channels, whereas the proposed lower bound is more general and applies to Rician fading channels. Moreover, it is explicitly demonstrated that the proposed lower and upper bounds become asymptotically exact in the high signal-to-noise ratio (SNR) regime. Based on our analytical expressions and numerical results, we gain valuable insights into the impact of model parameters on the capacity of fixed-gain AF dual-hop relaying systems. © 2011 IEEE.