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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Validation of a Redwood Sequoia Sempervirens (D. Don) Endl Butt Log Sawing Simulator

Ashford, Sheridan January 2013 (has links)
Redwood (Sequoia sempervirens (D. Don) Endl.) has been identified as a species with considerable potential for plantation forestry in New Zealand. Investment decisions in high value alternate species must be based on accurate wood quality and value predictions. There is an opportunity to extend non-destructive evaluation tools available to redwood growers, and to present the outputs of the growth model by log products and sawn timber. A redwood pruned buttlog sawing simulator has been developed however the simulator had not been tested with real data. Twelve redwood trees from Mangatu estate were selected for a sawing study; these logs were reconstructed and run through the sawing simulator. Computerised log processing was used to produce simulated pruned log sawing outturn from the redwood Buttlog Sawing Simulator, and results were compared to real results from a sawing study. The objective of the study was therefore to determine how well the simulator matched volume and grade out-turn from twelve logs. This study found the many inconsistencies between simulated data and real data; particularly related to log size. While this study was unsuccessful in validation of the redwood sawing simulator, it provides initial insight into the simulators strengths and short comings.
2

Ascospore viability and dispersal from pruned branches infected with Anisogramma anomala

Heckert, Stephanie 29 November 2011 (has links)
Viability and dispersal of ascospores of Anisogramma anomala, the cause of eastern filbert blight (EFB) on European hazelnut, from diseased branches pruned from trees were measured. In each of two years, branches bearing stromata of A. anomala were cut in mid-December and compared to branches cut near budbreak in March, when trees became susceptible to infection. The experiment was replicated three times at separated locations. At each location, 125 diseased branches (source) were piled loosely in a 1 x 1 m area. From March to June, spore traps (rain sampling-type) as well as 2-year-old potted hazelnut trees were placed next to each source, 6.4 m upwind and downwind, and 20 m downwind from each source. During seven significant major rain events over the two seasons, hazelnut seedlings (3-month-old) were placed adjacent to the spore traps. Near sources significantly higher (P. < 0.01) ascospores counts were obtained for branches cut near budbreak compared to those pruned in December in the first season; no significant difference in counts of ascospores were observed in the second season between pruning treatments. For both seasons significantly higher (P < 0.05) counts of ascospores were observed at 6.4 m downwind compared to 6.4 m upwind or 20 m downwind of a source. Ascospore viability, as assessed by staining with trypan blue, was similar for both pruning times at all distances and averaged 50%. At least one infected seedling was obtained for 5 of 7 major rain events regardless of pruning time at sources and 3 of 7 major rain events 6.4 m downwind of a source. All of the 2-year-old potted trees for both pruning treatments at the source and 6.4 m downwind became diseased and > 50% of trees at 20 m downwind became diseased in the 2010 season. Similar to ascospores counts, disease incidence was significantly higher (P < 0.01) in 2-year-old potted trees observed 6.4 m downwind compared to 6.4 m upwind or 20 m downwind in the 2010 season. Significantly higher (P < 0.01) disease incidence in 2-year-old potted trees was observed 20 m downwind compared to 6.4 m upwind in the 2010 season. Downwind disease gradients for both pruning treatments were shallow with slopes that were not significantly different than zero (p > 0.05) for the 2010 season. Based on these results, ascospores from diseased branches pruned from trees in both pruning treatments remained viable, infectious and were dispersed downwind of each treatment. / Graduation date: 2012
3

Resgate vegetativo e propagação in vitro de Persea willdenovii Kosterm.

Meneguzzi, Aline 17 February 2017 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-13T13:00:43Z No. of bitstreams: 1 PGEF17MA075.pdf: 2618024 bytes, checksum: d2a8781e299067e8fc5f0691bd03b8a5 (MD5) / Made available in DSpace on 2017-12-13T13:00:43Z (GMT). No. of bitstreams: 1 PGEF17MA075.pdf: 2618024 bytes, checksum: d2a8781e299067e8fc5f0691bd03b8a5 (MD5) Previous issue date: 2017-02-17 / Capes / The objective of this study was to determine method to the rescue of vegetative material of adult plants of P. willdenovii and evaluate the spread of this material, via tissue culture. The work was conducted with 20 P. willdenovii matrices located in Urupema / SC (28°17'38 ''S, 49°55'54''W). In the vegetative rescue, the following techniques were tested: trunk annealing (100%), semianelation at 75% of the trunk circumference, semianelation at 50% trunk and the induction of shoots from pruned branches. The shoots were harvested at 90, 120, 150, 180, 210 and 240 days after application of the treatments. Sprouts were used in the in vitro culture technique. In the establishment of shoots, asepsis methods were tested: 15 and 20 minutes of contact with sodium hypochlorite (NaClO) (2% v v-1) and the presence / absence of the PPM® biocide (1,5mL L-1) In the culture medium. For in vitro multiplication, two culture media (MS and WPM) and BAP concentration (0, 2, 4 and 6 mg L-1) were tested. Also, the induction of calogenesis by foliar explant was tested in the treatments: position of contact of the foliar face with the culture medium (up and down) and the combination of the BAP and ANA phytoregulators in different concentrations (0 to 12 mg L-1). All vegetative material rescue techniques emitted new shoots, with emphasis on the pruned branches method, which presented the best results for sprouting percentage, number and length of shoots. In vitro culture, asepsis of explants with NaClO for 20 minutes and addition of PPM® in the medium resulted in lower rates of fungal (50%), bacterial (5%), oxidation (23%) and higher survival (76%) of the explants. In vitro multiplication, explants in MS medium had higher oxidation (48%) and lower survival (52%) when compared to WPM medium (26% and 74%, respectively). For the average number of shoots and leaves, the concentration of 3 mg L-1 BAP reached the highest technical efficiency (MET) (1.22 and 1.75 mg L-1, respectively). Foliar segments were not responsive in inducing calogenesis after 120 days of in vitro culture. In this way, it is indicated for the vegetative rescue of P. willdenovii the method of pruned branches. While for in vitro propagation, the use of NaClO (2% v v-1) for 20 minutes and the PPM® biocide (1.5 ml L-1) in the culture medium is recommended in the establishment phase and The use of WPM medium plus 3 mg L-1 of BAP in the multiplication phase. / O objetivo deste trabalho foi determinar método para o resgate de material vegetativo de plantas adultas de P. willdenovii e avaliar a propagação deste material, via cultura de tecidos. Foram utilizadas 20 árvores matrizes de P. willdenovii localizadas no município de Urupema/SC (28°17'38''S; 49°55'54''W). No resgate vegetativo, foram testadas as seguintes técnicas: anelamento do tronco, semianelamento em 75% da circunferência do tronco, semianelamento em 50% e galhos podados. As coletas das brotações foram realizadas aos 90, 120, 150, 180, 210 e 240 dias após a aplicação dos tratamentos. As brotações foram utilizadas na técnica de cultivo in vitro. No estabelecimento testaram-se métodos de assepsia: 15 e 20 minutos de contato com hipoclorito de sódio (NaClO) (2% v v-1) e a presença/ausência do biocida PPM® (1,5mL L-1) no meio de cultura. Para a multiplicação in vitro, foram testados meios de cultura (MS e WPM) e doses de BAP (0, 2, 4 e 6 mg L-1). Também, foi testada a indução de calogênese via explante foliar, nos tratamentos: posição de contato da face foliar com o meio de cultivo (abaxial e adaxial) e a combinação dos fitorreguladores BAP e ANA em diferentes concentrações (de 0 a 12 mg L-1). Todas as técnicas de resgate de material vegetativo emitiram novos brotos, com destaque para o método via galhos podados que apresentou os melhores resultados para porcentagem de brotação, número e comprimento de brotos. No cultivo in vitro, a assepsia dos explantes com NaClO por 20 minutos e a adição do PPM® no meio resultou em menores índices de contaminação fúngica (50%), bacteriana (5%), oxidação (23%) e maior sobrevivência (76%) dos explantes. Na multiplicação in vitro, os explantes em meio MS tiveram maior oxidação (48%) e menor sobrevivência (52%) quando comparado ao meio WPM (26% e 74%, respectivamente). Para o número médio de brotos e de folhas, a concentração de 3 mg L-1 BAP atingiu a máxima eficiência técnica (MET) (1,22 e 1,75 mg L-1, respectivamente). Os segmentos foliares não foram responsivos na indução de calogênese após 120 dias de cultivo in vitro. Desta forma, indica-se para o resgate vegetativo de P. willdenovii o método de galhos podados. Enquanto que, para a propagação in vitro, recomenda-se o uso de NaClO (2% v v-1) durante 20 minutos e do biocida PPM® (1,5 ml L-1) no meio de cultura na fase de estabelecimento e a utilização do meio WPM acrescido de 3 mg L-1 de BAP na fase de multiplicação
4

Dynamic stochastic block models, clustering and segmentation in dynamic graphs / Modèles à bloques stochastiques dynamiques pour la classification et la segmentation des graphes dynamiques

Corneli, Marco 17 November 2017 (has links)
Cette thèse porte sur l’analyse de graphes dynamiques, définis en temps discret ou continu. Nous introduisons une nouvelle extension dynamique du modèle a blocs stochastiques (SBM), appelée dSBM, qui utilise des processus de Poisson non homogènes pour modéliser les interactions parmi les paires de nœuds d’un graphe dynamique. Les fonctions d’intensité des processus ne dépendent que des classes des nœuds comme dans SBM. De plus, ces fonctions d’intensité ont des propriétés de régularité sur des intervalles temporels qui sont à estimer, et à l’intérieur desquels les processus de Poisson redeviennent homogènes. Un récent algorithme d’estimation pour SBM, qui repose sur la maximisation d’un critère exact (ICL exacte) est ici adopté pour estimer les paramètres de dSBM et sélectionner simultanément le modèle optimal. Ensuite, un algorithme exact pour la détection de rupture dans les séries temporelles, la méthode «pruned exact linear time» (PELT), est étendu pour faire de la détection de rupture dans des données de graphe dynamique selon le modèle dSBM. Enfin, le modèle dSBM est étendu ultérieurement pour faire de l’analyse de réseau textuel dynamique. Les réseaux sociaux sont un exemple de réseaux textuels: les acteurs s’échangent des documents (posts, tweets, etc.) dont le contenu textuel peut être utilisé pour faire de la classification et détecter la structure temporelle du graphe dynamique. Le modèle que nous introduisons est appelé «dynamic stochastic topic block model» (dSTBM). / This thesis focuses on the statistical analysis of dynamic graphs, both defined in discrete or continuous time. We introduce a new extension of the stochastic block model (SBM) for dynamic graphs. The proposed approach, called dSBM, adopts non homogeneous Poisson processes to model the interaction times between pairs of nodes in dynamic graphs, either in discrete or continuous time. The intensity functions of the processes only depend on the node clusters, in a block modelling perspective. Moreover, all the intensity functions share some regularity properties on hidden time intervals that need to be estimated. A recent estimation algorithm for SBM, based on the greedy maximization of an exact criterion (exact ICL) is adopted for inference and model selection in dSBM. Moreover, an exact algorithm for change point detection in time series, the "pruned exact linear time" (PELT) method is extended to deal with dynamic graph data modelled via dSBM. The approach we propose can be used for change point analysis in graph data. Finally, a further extension of dSBM is developed to analyse dynamic net- works with textual edges (like social networks, for instance). In this context, the graph edges are associated with documents exchanged between the corresponding vertices. The textual content of the documents can provide additional information about the dynamic graph topological structure. The new model we propose is called "dynamic stochastic topic block model" (dSTBM).Graphs are mathematical structures very suitable to model interactions between objects or actors of interest. Several real networks such as communication networks, financial transaction networks, mobile telephone networks and social networks (Facebook, Linkedin, etc.) can be modelled via graphs. When observing a network, the time variable comes into play in two different ways: we can study the time dates at which the interactions occur and/or the interaction time spans. This thesis only focuses on the first time dimension and each interaction is assumed to be instantaneous, for simplicity. Hence, the network evolution is given by the interaction time dates only. In this framework, graphs can be used in two different ways to model networks. Discrete time […] Continuous time […]. In this thesis both these perspectives are adopted, alternatively. We consider new unsupervised methods to cluster the vertices of a graph into groups of homogeneous connection profiles. In this manuscript, the node groups are assumed to be time invariant to avoid possible identifiability issues. Moreover, the approaches that we propose aim to detect structural changes in the way the node clusters interact with each other. The building block of this thesis is the stochastic block model (SBM), a probabilistic approach initially used in social sciences. The standard SBM assumes that the nodes of a graph belong to hidden (disjoint) clusters and that the probability of observing an edge between two nodes only depends on their clusters. Since no further assumption is made on the connection probabilities, SBM is a very flexible model able to detect different network topologies (hubs, stars, communities, etc.).
5

Aproximações para DCT via pruning com aplicações em codificação de imagem e vídeo

COUTINHO, Vítor de Andrade 23 February 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-06-21T15:14:55Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Vitor_de_Andrade_Coutinho-dissertacao_ppgee.pdf: 3622975 bytes, checksum: 01a22e0302dfc1890d745c6b1bffe327 (MD5) / Made available in DSpace on 2016-06-21T15:14:56Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Vitor_de_Andrade_Coutinho-dissertacao_ppgee.pdf: 3622975 bytes, checksum: 01a22e0302dfc1890d745c6b1bffe327 (MD5) Previous issue date: 2015-02-23 / CNPq / O presente trabalho aborda o desenvolvimento de aproximações para a transformada dis- reta do osseno (DCT) utilizando a abordagem pruning. Devido à propriedade da ompa ta- ção de energia, a DCT é empregada em diversas apli ações de ompressão de dados. Embora algoritmos rápidos permitam omputar a DCT e ientemente, operações de multipli ação são inevitáveis. Devido a res ente demanda por métodos de baixo onsumo energéti o, novos algoritmos de usto omputa ional reduzido são ne essários. Neste ontexto, aproximações para a DCT foram propostas nos últimos anos. Tais aproximações permitem algoritmos livres de multipli ação, sem a ne essidade de operações de ponto utuante, mantendo o desempe- nho de ompressão omparável ao forne ido por métodos baseados na DCT. Uma abordagem adi ional para reduzir o usto omputa ional da DCT é a utilização de pruning. Tal té ni a onsiste em não onsiderar oe ientes dos vetores de entrada e/ou saída que apresentam menor relevân ia em termos de energia on entrada. No aso da DCT, esses oe ientes são os termos de mais alta frequên ia do vetor transformado. A apli ação de pruning a aproxima- ções para a DCT é uma área pou o explorada. O objetivo deste trabalho é apli ar a té ni a a diferentes métodos aproximados para a DCT. As transformações resultantes foram apli adas no ontexto de ompressão de imagem e vídeo e os resultados mostraram desempenho ompa- rável ao de métodos exatos a um usto omputa ional bastante reduzido. Uma generalização do on eito é apresentada, assim omo uma análise da omplexidade aritméti a. / This work introdu es approximate dis rete osine transforms (DCT) based on the pruning approa h. Due to the energy ompa tion property, the DCT is employed in several data ompression appli ations. Although fast algorithms allow an e ient DCT omputation, multipli ation operations are inevitable. Due to the in reasing demand for energy e ient methods, new algorithms with redu ed omputational ost are required. In this ontext, DCT approximations have been proposed re ently. Su h approximations allow multipli ation free algorithms whi h an avoid oating point operations, while maintaining a ompetitive performan e. A further approa h to redu e the omputational ost of the DCT is pruning. The te hnique onsists of dis arding input and/or output ve tors oe ients whi h are regarded as less signi ant. In the ase of the DCT, su h oe ients are output oe ients asso iated to higher frequen y terms. Pruned DCT approximations is a relatively unexplored eld of resear h. The obje tive of this work is the ombination of approximations and pruning to derive extremely low- omplexity DCT approximations. The resulting methods were applied in the image and vídeo ompression s enario and results showed omparative performan e with exa t methods at a mu h lower omputational omplexity. A qualitative and quantitative omparison with a omprehensive list of existing methods is presented. A generalization of the pruning on ept is presented.

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