Search results for " key"
showing 10 items of 409 documents
Super-orthogonal space-time trellis codes with differential phase modulation for noncoherent mobile communication systems
2010
In this paper, we show how to design super-orthogonal space-time trellis codes (SOSTTCs) using the differential binary phase-shift keying (PSK) modulation for noncoherent communication systems, for which the knowledge of the channel state information (CSI) at the receiver is not necessary. Moreover, a new decoding algorithm with reduced decoding complexity is proposed. In all simulations, a geometric two-ring channel model is employed to evaluate the performance of the SOSTTCs. The simulation results show that the proposed decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while the new algorithm reduces significantly the overall computing …
Buffer strips can pre-empt extinction debt in boreal streamside habitats
2013
Background Conservation of biological diversity and economical utilization of natural resources form an almost inevitable confrontation between the two. In practice, however, a balance between the two ought to be found, and in managed boreal forests, preservation of woodland key habitats is increasingly used strategy to safeguard biological diversity. According to the Finnish Forests Act, certain Forest Act habitat (FAH) types must be safeguarded, provided they are clearly distinguishable from their surroundings. Furthermore, once the habitat has been identified as a FAH, its special characteristics must not be altered. Both of these aspects contain ambiguities that potentially undermine th…
Collaborative business planning in initial vocational education and training
2015
There is a growing demand to enhance entrepreneurship. This study aims at producing knowledge that can assist teachers in designing and supporting collaborative learning of entrepreneurship in vocational education. A qualitative case study approach was adopted. The outcome of this study provides a better understanding of the factors that hinder and enable collaboration, as related to entrepreneurship education in initial vocational education and training. In practice, nine dimensions of descriptive factors that hindered the exercise and nine distinct descriptive factors that acted as enablers were identified. This study suggests that, although the script of the learning task creates the set…
A new Aphid genus and species (Hemiptera: Aphididae: Macrosiphini) living on ferns in Costa Rica and Mexico
2013
AbstractAphid species colonising ferns belong to the subfamily Aphidinae (Hemiptera: Aphididae) and the majority of these to the tribe Macrosiphini. A new genus in this tribe and its type species: Gibbomyzus pteridophytorumnew genus, new species, are established. Apterous and alate viviparous females are described from specimens collected on Blechnum buchtienii Rosenstock (Blechnaceae) in Costa Rica and on Pteridium aquilinum (Linnaeus) Kuhn (Dennstaedtiaceae) and an unidentified fern in Mexico. The taxonomic validity of the two new taxa is discussed based on morphological and molecular data. Morphologically, the new genus is compared with genera with swollen siphunculi recorded in the New …
New discoveries in New World Atissini as revealed in revision of Pelignellus Sturtevant & Wheeler (Diptera: Ephydridae)
2019
Pelignellus is resurrected from synonymy with Atissa and is revised. The genus and both included species—P. subnudus Sturtevant & Wheeler from the USA (California) and P. freidbergi n. sp. from Central America (Costa Rica, El Salvador, Panama)—are described with an emphasis on structures of the male terminalia, which are fully illustrated. The species are keyed and their distribution data are provided. For perspective and to facilitate recognition of genera and species, the tribe Atissini is diagnosed and a key to genera is provided.
Synthèse de ligands macrocycliques comportant des fragments aromatiques et leur application pour la détection des cations métalliques
2011
The PhD thesis deals with the synthesis of polyazaligands using Pd-catalyzed amination of aryl halides. The manuscript consists of two parts. In the first part the scope of the Pd-catalyzed amination reaction for the synthesis of polyazamacrocyclic ligands is studied. The Pd-catalyzed amination of 2,7-dibromonaphthalene, 3,3’-dibromobiphenyl and 6,6’-dibromo-2,2’-bipyridyl with linear polyamines and oxadiamines is thoroughly investigated, and corresponding nitrogen- and oxygen-containing macrocycles is synthesized in yields up to 45%. The dependence of the formation of macrocycles and cyclic oligomers on the nature of the starting compounds is established. Two alternative approaches to cycl…
Simulation and laboratory experimental tests of a line to shield medium voltage power line communication system
2011
A complete model of a power-line communication (PLC) system on a medium-voltage (MV) network in the case of a line-shield configuration is presented in this paper. An MV cable model in a line-shield configuration is considered together with the power transformers, the signal coupling networks, and the receiving and transmitting line coupling interface of a ST7540 FSK power-line transceiver. Simulations of the complete model of the system under consideration have been carried out for different line lengths, with and without power transformers and derivation branches. The model is validated by experimental tests performed in the laboratory. The measured results confirm the reliability of the …
Asociaciones de inmigrantes, Estados y desarrollo entre España y Colombia. ¿Un nuevo campo social transnacional?
2017
A pesar de la distancia geografica, las asociaciones de inmigrantes colombianos en Espana han tenido una creciente incidencia en los asuntos locales de su pais de origen, y sus acciones han ido adquiriendo una progresiva dimension transnacional. Entre otras practicas, las asociaciones han implementado numerosos proyectos de desarrollo en Colombia que han implicado la movilizacion de redes verticales y horizontales, tanto en el pais de origen como en el de destino, en paralelo con el renovado interes de los Estados colombiano y espanol por dar soporte a esas acciones. En este articulo nos preguntamos en que medida estas dinamicas, inducidas por la migracion, podrian haber contribuido a la co…
Adolescentes y drogas : su relación con la delincuencia
2016
Esta investigación describe la relación con las drogas en una muestra de 286 Adolescentes en Conflicto con la Ley de la ciudad de Valencia (España). Tiene por objeto analizar la relación entre trayectoria delictiva y consumo de drogas. Los resultados informan que, a mayor incidencia delictiva, mayor dependencia. En cuanto a patrones de consumo por tipo de sustancia, el cannabis se asocia a trayectorias delictivas iniciales, y la cocaína, a trayectorias consolidadas. El consumo se produce en escenarios habituales diurnos y se extiende a otros de ocio nocturno, y particularmente forma parte de la trayectoria consolidada en la vida cotidiana de los adolescentes en conflicto con la ley. This st…
First demonstration of active plasmonic device in true data traffic conditions: On/off thermo-optic modulation using a hybrid silicon-plasmonic asymm…
2012
We demonstrate the first system-level evaluation of an active plasmonic device in 10Gb/s data traffic conditions. Thermo-optic ON/OFF modulation with 3μs response time and 10mW power consumption is presented using an asymmetric MZI silicon-plasmonic gate.