63 research outputs found

    REACTION OF SOME WALNUT GENOTYPES GROWN IN VÂLCEA AREA AT GNOMONIA LEPTOSTYLA CES. ET DE NOT PATHOGEN ATTACK

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    The studies were conducted at the Research Fruit  Growing the Station of Valcea, under the climatic conditions of the year 2015 and focused response of walnut cultivars and selections with different origins to the attack the of  Gnomonia leptostyla Ces.et de Not factor causative of the disease called "brown staining of leaves" or "walnut anthracnose." Field observations were carried out at moments of maximum vulnerability to the disease (June and September) and followed up on the attack on leaves and fruits per genotype under natural infection. At the two moments of observation,  it was noted the frequency (F%) and the intensity (I%) of the pathogen attack based on which a was the calculated degree of attack (GA%), the values thereof reflecting the reaction of the cultivars to the attack of the pathogen

    CONTRIBUTIONS TO THE STUDY OF THE COMPOSITION AND DYNAMICS OF THE ARTHROPOD FAUNA FROM SOME CORN CROPS IN THE N-E REGION OF MOLDOVA

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    In order to maintain biodiversity on intensively exploited agricultural land, the monitoring of harmful and useful species is extremely important, as it provides information on the quality of the land and, why not, can provide predictions on the stability of agroecosystems. The observations regarding the structure of the arthropod entomofauna were made between April and July in the year 2021 in a corn crop in the town of Ghigoiesti. The research carried out aimed to determine the structure and composition of the entomofauna, its abundance and diversity as well as their behavior in the maize crops in the station under observation, and the research was based on the use of Barber-type soil traps, a total of 6, placed in 3 in a row, which have as fixing solution a salt solution (NaCl) with a concentration of 20% for each of the three variants studied. The collected material is represented by species belonging to the arthropod fauna that systematically fall into the following orders: Coleoptera, Hymenoptera, Orthoptera, Diptera, Arachnida s.a

    Tatouage du flux compressé MPEG-4 AVC

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    La présente thèse aborde le sujet de tatouage du flux MPEG-4 AVC sur ses deux volets théoriques et applicatifs en considérant deux domaines applicatifs à savoir la protection du droit d auteur et la vérification de l'intégrité du contenu. Du point de vue théorique, le principal enjeu est de développer un cadre de tatouage unitaire en mesure de servir les deux applications mentionnées ci-dessus. Du point de vue méthodologique, le défi consiste à instancier ce cadre théorique pour servir les applications visées. La première contribution principale consiste à définir un cadre théorique pour le tatouage multi symboles à base de modulation d index de quantification (m-QIM). La règle d insertion QIM a été généralisée du cas binaire au cas multi-symboles et la règle de détection optimale (minimisant la probabilité d erreur à la détection en condition du bruit blanc, additif et gaussien) a été établie. Il est ainsi démontré que la quantité d information insérée peut être augmentée par un facteur de log2m tout en gardant les mêmes contraintes de robustesse et de transparence. Une quantité d information de 150 bits par minutes, soit environ 20 fois plus grande que la limite imposée par la norme DCI est obtenue. La deuxième contribution consiste à spécifier une opération de prétraitement qui permet d éliminer les impactes du phénomène du drift (propagation de la distorsion) dans le flux compressé MPEG-4 AVC. D abord, le problème a été formalisé algébriquement en se basant sur les expressions analytiques des opérations d encodage. Ensuite, le problème a été résolu sous la contrainte de prévention du drift. Une amélioration de la transparence avec des gains de 2 dB en PSNR est obtenueThe present thesis addresses the MPEG-4 AVC stream watermarking and considers two theoretical and applicative challenges, namely ownership protection and content integrity verification.From the theoretical point of view, the thesis main challenge is to develop a unitary watermarking framework (insertion/detection) able to serve the two above mentioned applications in the compressed domain. From the methodological point of view, the challenge is to instantiate this theoretical framework for serving the targeted applications. The thesis first main contribution consists in building the theoretical framework for the multi symbol watermarking based on quantization index modulation (m-QIM). The insertion rule is analytically designed by extending the binary QIM rule. The detection rule is optimized so as to ensure minimal probability of error under additive white Gaussian noise distributed attacks. It is thus demonstrated that the data payload can be increased by a factor of log2m, for prescribed transparency and additive Gaussian noise power. A data payload of 150 bits per minute, i.e. about 20 times larger than the limit imposed by the DCI standard, is obtained. The thesis second main theoretical contribution consists in specifying a preprocessing MPEG-4 AVC shaping operation which can eliminate the intra-frame drift effect. The drift represents the distortion spread in the compressed stream related to the MPEG encoding paradigm. In this respect, the drift distortion propagation problem in MPEG-4 AVC is algebraically expressed and the corresponding equations system is solved under drift-free constraints. The drift-free shaping results in gain in transparency of 2 dB in PSNREVRY-INT (912282302) / SudocSudocFranceF

    RESEARCH ON THE STRUCTURE AND ABUNDANCE OF BEETLES (ORD. COLEOPTERA)FROM SOME CORN CROPS IN NORTHERN MOLDOVA-ROMANIA

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    Within this station, three experimental variants were initiated that targeted the preceding culture. Therefore, the variants studied were: V1 maize in monoculture; V2 corn after sunflower; V3 corn after wheat. Barber-type soil traps were used to collect biological material, they worked continuously from April to July 2021, where a number of 5 collections were made for each variant. Barber traps consist of plastic containers of approx. 10-12 centimeters high and about 8-10 centimeters in diameter in which I used a salt solution (NaCl) with a concentration of about 20% as fixing liquid. Six traps were used for each experimental variant. Samples were collected at 12-15 day intervals when we changed the fixative – saline solution, replenished or, if necessary, replaced. The collected species were cleaned of all plant remains, other impurities, and then the coleoptera species were selected separately, and with the help of determinants they were identified. The structure, dynamics and abundance of coleopteran species were then determined according to each experimental variant, and the most frequently collected were: Tanymecus dilaticollis, Epicometis hirta, Coccinela 7- punctata, Harpalus calceatus, Harpalus distinguendus Formіcomus pedestrіs, Phyllotreta vittula, Opatrum sabulosum and Pentodonidiota

    Towards a multimedia remote viewer for mobile thin clients

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    Be there a traditional mobile user wanting to connect to a remote multimedia server. In order to allow them to enjoy the same user experience remotely (play, interact, edit, store and share capabilities) as in a traditional fixed LAN environment, several dead-locks are to be dealt with: (1) a heavy and heterogeneous content should be sent through a bandwidth constrained network; (2) the displayed content should be of good quality; (3) user interaction should be processed in real-time and (4) the complexity of the practical solution should not exceed the features of the mobile client in terms of CPU, memory and battery. The present paper takes this challenge and presents a fully operational MPEG-4 BiFS solution

    Networked digital media

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    Abdominal Tumor Characterization and Recognition Using Superior-Order Cooccurrence Matrices, Based on Ultrasound Images

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    The noninvasive diagnosis of the malignant tumors is an important issue in research nowadays. Our purpose is to elaborate computerized, texture-based methods for performing computer-aided characterization and automatic diagnosis of these tumors, using only the information from ultrasound images. In this paper, we considered some of the most frequent abdominal malignant tumors: the hepatocellular carcinoma and the colonic tumors. We compared these structures with the benign tumors and with other visually similar diseases. Besides the textural features that proved in our previous research to be useful in the characterization and recognition of the malignant tumors, we improved our method by using the grey level cooccurrence matrix and the edge orientation cooccurrence matrix of superior order. As resulted from our experiments, the new textural features increased the malignant tumor classification performance, also revealing visual and physical properties of these structures that emphasized the complex, chaotic structure of the corresponding tissue

    Méthodes de tatouage robuste pour la protection de l imagerie numerique 3D

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    La multiplication des contenus stéréoscopique augmente les risques de piratage numérique. La solution technologique par tatouage relève ce défi. En pratique, le défi d une approche de tatouage est d'atteindre l équilibre fonctionnel entre la transparence, la robustesse, la quantité d information insérée et le coût de calcul. Tandis que la capture et l'affichage du contenu 3D ne sont fondées que sur les deux vues gauche/droite, des représentations alternatives, comme les cartes de disparité devrait également être envisagée lors de la transmission/stockage. Une étude spécifique sur le domaine d insertion optimale devient alors nécessaire. Cette thèse aborde les défis mentionnés ci-dessus. Tout d'abord, une nouvelle carte de disparité (3D video-New Three Step Search- 3DV-SNSL) est développée. Les performances des 3DV-NTSS ont été évaluées en termes de qualité visuelle de l'image reconstruite et coût de calcul. En comparaison avec l'état de l'art (NTSS et FS-MPEG) des gains moyens de 2dB en PSNR et 0,1 en SSIM sont obtenus. Le coût de calcul est réduit par un facteur moyen entre 1,3 et 13. Deuxièmement, une étude comparative sur les principales classes héritées des méthodes de tatouage 2D et de leurs domaines d'insertion optimales connexes est effectuée. Quatre méthodes d'insertion appartenant aux familles SS, SI et hybride (Fast-IProtect) sont considérées. Les expériences ont mis en évidence que Fast-IProtect effectué dans la nouvelle carte de disparité (3DV-NTSS) serait suffisamment générique afin de servir une grande variété d'applications. La pertinence statistique des résultats est donnée par les limites de confiance de 95% et leurs erreurs relatives inférieurs er <0.1The explosion in stereoscopic video distribution increases the concerns over its copyright protection. Watermarking can be considered as the most flexible property right protection technology. The watermarking applicative issue is to reach the trade-off between the properties of transparency, robustness, data payload and computational cost. While the capturing and displaying of the 3D content are solely based on the two left/right views, some alternative representations, like the disparity maps should also be considered during transmission/storage. A specific study on the optimal (with respect to the above-mentioned properties) insertion domain is also required. The present thesis tackles the above-mentioned challenges. First, a new disparity map (3D video-New Three Step Search - 3DV-NTSS) is designed. The performances of the 3DV-NTSS were evaluated in terms of visual quality of the reconstructed image and computational cost. When compared with state of the art methods (NTSS and FS-MPEG) average gains of 2dB in PSNR and 0.1 in SSIM are obtained. The computational cost is reduced by average factors between 1.3 and 13. Second, a comparative study on the main classes of 2D inherited watermarking methods and on their related optimal insertion domains is carried out. Four insertion methods are considered; they belong to the SS, SI and hybrid (Fast-IProtect) families. The experiments brought to light that the Fast-IProtect performed in the new disparity map domain (3DV-NTSS) would be generic enough so as to serve a large variety of applications. The statistical relevance of the results is given by the 95% confidence limits and their underlying relative errors lower than er<0.1EVRY-INT (912282302) / SudocSudocFranceF

    Deep Learning Techniques for Liver Tumor Recognition in Ultrasound Images

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    Cancer is one of the most severe diseases nowadays. Thus, tumor detection in a non-invasive and accurate manner is a challenging subject. Among these tumors, liver cancer is one of the most dangerous, being very common. Hepatocellular Carcinoma (HCC) is the most frequent malignant liver tumor. The golden standard for diagnosing HCC is mainly the biopsy, however invasive and risky, leading to infections, respectively to the spreading of the tumor through the body. We conceive computerized techniques for abdominal tumor recognition within medical images. Formerly, traditional, texture-based methods were involved for this purpose. Both classical texture analysis methods, as well as advanced, original texture analysis techniques, based on superior order statistics, were involved. The superior order Gray Level Cooccurrence Matrix (GLCM), as well as the Textural Microstructure Cooccurrence Matrices (TMCM) were employed and assessed. Recently, deep learning techniques based on Convolutional Neural Networks (CNN), their fusions with the conventional techniques, as well as their combinations among themselves, were assessed in the approached field. We present the most relevant aspects of this study in the current paper

    The essential spectrum of the Neumann–Poincaré operator on a domain with corners

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    Exploiting the homogeneous structure of a wedge in the complex plane, we compute the spectrum of the anti-linear Ahlfors-Beurling transform acting on the associated Bergman space. Consequently, the similarity equivalence between the Ahlfors--Beurling transform and the Neumann-Poincare operator provides the spectrum of the latter integral operator on a wedge. A localization technique and conformal mapping lead to the first complete description of the essential spectrum of the Neumann-Poincare operator on a planar domain with corners, with respect to the energy norm of the associated harmonic field
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