189 research outputs found
Apanteles bordagei Giard 1902
No full textApanteles bordagei Giard, 1902 (Figs 5 e–f) Diagnosis. Scutellum and mesopleuron smooth and shining. Propodeum smooth with areola reduced to an apical fork. Fore wing with r and 2 Rs forming a curved continuous line without distinct angle. Tergum 1 distinctly narrowed apically. Ovipositor shorter than hind femur. Description. c f. Granger, 1949: 259 for details. Host records. Crobylophora daricella Meyrick, Leucoptera caffeina Washbourn, and L. meyricki (Ghesquière) (Lepidoptera: Lyonetiidae). Distribution records. Equatorial Africa, Madagascar and Reunion. Comments. Species described from Reunion as a parasitoid of the leaf miner L. caffeina. Coffea culture in Reunion has radically decreased since the end of the 19 th century and its replacement by sugarcane. Leucoptera caffeina is still present on the small remaining crops, though it is no more considered as a pest (F. Descroix, pers. com.), and A. bordagei has not been collected again since its description.Published as part of Rousse, Pascal & Gupta, Ankita, 2013, Microgastrinae (Hymenoptera: Braconidae) of Reunion Island: a catalogue of the local species, including 18 new taxa and a key to species, pp. 501-547 in Zootaxa 3616 (6) on page 508, DOI: 10.11646/zootaxa.3616.6.1, http://zenodo.org/record/21794
High-speed decoders for polar codes
No full textError detection and correction plays a vital role in modern information storage and communication systems. Polar codes are gathering a lot of attention as they are a class of capacity-achieving error-correcting codes with an explicit construction that can be decoded with low-complexity algorithms. However, their adoption is hindered by the lack of high-speed---high throughput and low latency---hardware and software decoders for codes of practical length and rate. This thesis presents various solutions to this problem. It introduces modifications to the state-of-the-art low-complexity decoding algorithm to better accommodate low-rate polar codes. It also proposes a code construction alteration process. Hardware implementation results show good latency reduction and throughput improvement with little to negligible coding loss for low-rate moderate-length polar codes. Then, it presents high-speed software polar decoders. It shows how adapting the decoding algorithm at various levels can lead to significant improvements in latency and throughput, yielding polar decoders that are suitable for high-performance software-defined radio applications on modern desktop processors and embed\-ded-plat\-form processors. These proposed decoders have an order of magnitude lower latency and memory footprint compared to state-of-the-art decoders, while maintaining comparable throughput. In addition, strategies and results for implementing polar decoders on graphical processing units are presented.Next, it demonstrates that polar decoders can achieve extremely high throughput values and retain moderate complexity. It presents a family of architectures for hardware polar decoders that employ unrolling. The resulting fully-unrolled architectures are capable of achieving a throughput that is two to three orders of magnitude greater than current state of the art while maintaining good energy efficiency. Moreover, the proposed architectures are flexible in a way that makes it possible to explore the trade-off between area, throughput and energy efficiency. Lastly, while unrolled decoders provide the greatest decoding speed, they are built for a specific, fixed, code i.e. the code length or rate cannot be modified at execution time. Most modern wireless communication applications largely benefit from the support of multiple code lengths and rates. This thesis shows how an unrolled decoder can be transformed into a multi-mode decoder supporting many codes of various lengths and rates. Implementation results show a peak information throughput that is an order of magnitude greater than the state of the art, while showing the best area and energy efficiency.La détection et la correction des erreurs jouent un rôle essentiel dans les systèmes modernes de stockage et de communication. Les codes polaires intriguent actuellement beaucoup de chercheurs car ils constituent une classe de codes correcteurs capables d'atteindre la capacité théorique d'un canal avec des algorithmes de décodage de faible complexité tout en proposant une méthode de construction explicite. Cependant, leur adoption est ralentie par le manque d'implémentation matérielle et logicielle de décodeurs hautes vitesses i.e. à faible latence et à haut débit. Cette thèse propose de multiples solutions à ce problème. Elle introduit d'abord des modifications à l'algorithme de décodage de faible complexité, qui est l'état de l'art, afin d'accommoder les codes polaires à faible taux de codage. Elle propose également une méthode d'altération de la construction des codes polaires. Les résultats d'implémentation matérielle montrent que, pour des codes polaires de longueur moyenne et de faible taux de codage, on obtient une bonne réduction de la latence ainsi qu'une augmentation appréciable du débit au coût d'une perte faible ou nulle en terme de performance de correction d'erreurs. Puis, elle présente des décodeurs polaires logiciels hautes vitesses. Elle montre, qu'en adaptant l'algorithme de décodage à divers niveaux, on obtient des améliorations significatives en terme de latence et de débit. Il en résulte des décodeurs polaires très intéressants pour les applications de radio logicielle haute performance s'exécutant sur processeur moderne de bureau ou de plate-forme embarquée. Les décodeurs proposés ont une latence et une empreinte mémoire qui est un ordre de grandeur inférieur par rapport à l'état de l'art tout en maintenant un débit compétitif. De plus, des stratégies ainsi que des résultats pour l'implémentation de décodeurs polaires sont présentés pour des processeurs graphiques généralistes. Ensuite, elle démontre que les décodeurs de codes polaires peuvent atteindre des débits excessivement élevés tout en conservant une complexité modérée. Elle présente une famille d'architecture matérielle pour les décodeurs de code polaire faisant appel à la technique de déroulage. Les architectures complètement déroulées qui en résultent sont capables d'atteindre des débits qui sont de deux à trois fois plus élevés que l'état de l'art tout en maintenant une bonne efficacité énergétique. De plus, les architectures proposées sont flexibles de sorte qu'il est possible d'explorer les compromis entre la surface, le débit et l'efficacité énergétique. Enfin, bien que les décodeurs déroulés offrent la meilleure vitesse, ils sont construits pour un code spécifique i.e. un code d'une longueur et d'un taux de codage qui ne peuvent être modifiés au moment de l'exécution. Les systèmes de communication sans-fil modernes bénéficient du support de multiple codes de longueurs et de taux variés. Ainsi, cette thèse montre comment un décodeur déroulé peut être transformé en décodeur multimode supportant plusieurs codes de longueurs et de taux variés. Les résultats d'implémentation montrent un débit nominal qui est un ordre de grandeur plus élevé que l'état de l'art tout en montrant les meilleurs taux d'efficacité en terme de surface et d'énergie
Dorsale de communication CORBA pour la conception et la vérification fonctionnelle de circuits électroniques numériques complexes
No full textCe mémoire présente une stratégie novatrice de communication basée sur des objets pour interconnecter des outils de conception et des composantes systèmes opérant à des niveaux d’abstraction différents afin de produire un système cohérent et compatible. Les modules d’interconnexion sont générés automatiquement à partir de modèles d’interface. Cet environnement s’utilise pour le prototypage, la validation, la simulation et le test des interactions de systèmes complexes avant que ne soient terminées l’intégration et la conception de l’ensemble des composantes. Les résultats montrent une augmentation de 20% du temps de simulation par rapport à Link for ModelSim de MathWorks alors qu’il s’agit d’une solution générique par rapport à l’offre à fort couplage de MathWorks
Apanteles
No full textKey to Apanteles species in Reunion 1 Propodeum polished with areola reduced to a small apical fork (Fig. 5 f)............................ A. bordagei Giard – Propodeum with a distinct areola, at least apically and laterally defined, usually with distinct costulae and often basally closed (Figs 4 c, 4 e, 5 c–d, 5 h, 6 b, 6 e)............................................................................ 2 2 (1) Most venation of fore wing translucent: pterostigma and veins of the anterior margin fully colored, including sometimes the veins Rs and r–m, all other veins tubular but unpigmented (Fig. 4 d, 5 b)........................................... 3 – Fore wing with venation sometimes partially pale but not so discolored........................................... 4 3 (2) Propodeum with costulae present (Fig. 5 c), hind femur black.............................. A. nigrofemoratus Granger – Propodeum with costulae hardly distinguishable (Fig. 4 e), hind femur lighter......................... A. romei sp. nov. 4 (2) Propodeum with costulae present and strong, clearly distinguishable from the background sculpture (Figs 4 c, 5 c–d, 6 b, 6 e); flagellomere 15 of female barely to distinctly longer than wide.................................................. 5 – Propodeum with costulae absent or hardly distinct among rugosities (Fig. 5 h); flagellomere 15 of female quadrate or nearly so.................................................................................................... 6 5 (4) Hind coxa punctate above and nearly smooth laterally; hind tibia apically infuscate................. A. minatchy sp. nov. – Entire hind coxa densely punctate-rugose; hind tibia usually strikingly bicolor (black and yellow).... A. fontinalis de Saeger 6 (4) Posterior half of mesopleuron smooth, pterostigma enlarged (length / width = 2.0)................. A. galleriae Wilkinson – Posterior half of mesopleuron finely aciculate, pterostigma not enlarged (length / width = 2.8)......... A. pashmina sp. nov.Published as part of Rousse, Pascal & Gupta, Ankita, 2013, Microgastrinae (Hymenoptera: Braconidae) of Reunion Island: a catalogue of the local species, including 18 new taxa and a key to species, pp. 501-547 in Zootaxa 3616 (6) on page 508, DOI: 10.11646/zootaxa.3616.6.1, http://zenodo.org/record/21794
Fast-SSC-Flip Decoding of Polar Codes
No full textPolar codes are widely considered as one of the most exciting recent discoveries in channel coding. For short to moderate block lengths, their error-correction performance under list decoding can outperform that of other modern error-correcting codes. However, high-speed list-based decoders with moderate complexity are challenging to implement. Successive-cancellation (SC)-flip decoding was shown to be capable of a competitive error-correction performance compared to that of list decoding with a small list size, at a fraction of the complexity, but suffers from a variable execution time and a higher worst-case latency. In this work, we show how to modify the state-of-the-art high-speed SC decoding algorithm to incorporate the SC-flip ideas. The algorithmic improvements are presented as well as average execution-time results tailored to a hardware implementation. The results show that the proposed fast-SSC-flip algorithm has a decoding speed close to an order of magnitude better than the previous works while retaining a comparable error-correction performance.TC
Pour une meilleure défensive contre la fraude informatique
No full textIt is still difficult to say exactly what measures should be taken to prevent computer theft. Mr. Yves Giard's article indicates that a complete solution is very far away. Much more research on computer information will be needed, and solutions will probably emerge gradually, as we become more familiar with computer operations. For the moment, we can only discuss general ideas, and trust to luck, rather than science, to prevent theft or information leaks, or at least to detect them when they reach a certain scale. Currently, we have the impression of being, if not totally disarmed, at least with very little power of control over the numerous problems that can arise in the field of computer security. The author gives some ideas of accounting practices which are used in certain cases
A survey of administrative and teacher attitude toward the lengthening of the school day
No full textThesis (M.A.)--Boston Universit
Comparison of Polar Decoders with Existing Low-Density Parity-Check and Turbo Decoders
No full textPolar codes are a recently proposed family of provably capacity-achieving error-correction codes that received a lot of attention. While their theoretical properties render them interesting, their practicality compared to other types of codes has not been thoroughly studied. Towards this end, in this paper, we perform a comparison of polar decoders against LDPC and Turbo decoders that are used in existing communications standards. More specifically, we compare both the error-correction performance and the hardware efficiency of the corresponding hardware implementations. This comparison enables us to identify applications where polar codes are superior to existing error-correction coding solutions as well as to determine the most promising research direction in terms of the hardware implementation of polar decoders.TC
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