Relevant bibliographies by topics / Code distance

Academic literature on the topic 'Code distance'

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Published: 30 May 2022
Last updated: 31 May 2022

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Journal articles on the topic "Code distance"

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Gabidulin, E. M., and N. I. Pilipchuk. "Multicomponent codes with maximum code distance." Problems of Information Transmission 52, no. 3 (July 2016): 276–83. http://dx.doi.org/10.1134/s0032946016030054.

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Soloviev, Alexander A., and Dmitry V. Chernikov. "Biorthogonal wavelet codes with prescribed code distance." Discrete Mathematics and Applications 28, no. 3 (June 26, 2018): 179–88. http://dx.doi.org/10.1515/dma-2018-0017.

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Abstract We propose a scheme of construction of 2-circulant codes with given code distance on the basis of biorthogonal filters with the property of perfect reconstruction over a finite filed of odd characteristic. The corresponding algorithm for constructing biorthogonal filters utilizes the Euclidean algorithm for finding the gcd of polynomials.
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Stepanov, S. A. "Nonlinear q-ary codes with large code distance." Problems of Information Transmission 53, no. 3 (April 4, 2017): 242–50. http://dx.doi.org/10.1134/s003294601703005x.

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Hall, J. I., and J. H. van Lint. "Constant distance code pairs." Indagationes Mathematicae (Proceedings) 88, no. 1 (March 1985): 41–45. http://dx.doi.org/10.1016/s1385-7258(85)80018-4.

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Olivares, J., L. M. Sarro, H. Bouy, N. Miret-Roig, L. Casamiquela, P. A. B. Galli, A. Berihuete, and Y. Tarricq. "Kalkayotl: A cluster distance inference code." Astronomy & Astrophysics 644 (November 24, 2020): A7. http://dx.doi.org/10.1051/0004-6361/202037846.

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Context. The high-precision parallax data of the Gaia mission allows for significant improvements in the distance determination to stellar clusters and their stars. In order to obtain accurate and precise distance determinations, systematics such as parallax spatial correlations need to be accounted for, especially with regard to stars in small sky regions. Aims. Our aim is to provide the astrophysical community with a free and open code designed to simultaneously infer cluster parameters (i.e., distance and size) and distances to the cluster stars using Gaia parallax measurements. The code includes cluster-oriented prior families and it is specifically designed to deal with the Gaia parallax spatial correlations. Methods. A Bayesian hierarchical model is created to allow for the inference of both the cluster parameters and distances to its stars. Results. Using synthetic data that mimics Gaia parallax uncertainties and spatial correlations, we observe that our cluster-oriented prior families result in distance estimates with smaller errors than those obtained with an exponentially decreasing space density prior. In addition, the treatment of the parallax spatial correlations minimizes errors in the estimated cluster size and stellar distances, and avoids the underestimation of uncertainties. Although neglecting the parallax spatial correlations has no impact on the accuracy of cluster distance determinations, it underestimates the uncertainties and may result in measurements that are incompatible with the true value (i.e., falling beyond the 2σ uncertainties). Conclusions. The combination of prior knowledge with the treatment of Gaia parallax spatial correlations produces accurate (error < 10%) and trustworthy estimates (i.e., true values contained within the 2σ uncertainties) of cluster distances for clusters up to ∼5 kpc, along with cluster sizes for clusters up to ∼1 kpc.
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Delfosse, Nicolas, and Matthew B. Hastings. "Union-Find Decoders For Homological Product Codes." Quantum 5 (March 10, 2021): 406. http://dx.doi.org/10.22331/q-2021-03-10-406.

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Homological product codes are a class of codes that can have improved distance while retaining relatively low stabilizer weight. We show how to build union-find decoders for these codes, using a union-find decoder for one of the codes in the product and a brute force decoder for the other code. We apply this construction to the specific case of the product of a surface code with a small code such as a [[4,2,2]] code, which we call an augmented surface code. The distance of the augmented surface code is the product of the distance of the surface code with that of the small code, and the union-find decoder, with slight modifications, can decode errors up to half the distance. We present numerical simulations, showing that while the threshold of these augmented codes is lower than that of the surface code, the low noise performance is improved.
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Hastings, Mathew B. "Weight reduction for quantum codes." Quantum Information and Computation 17, no. 15&16 (December 2017): 1307–34. http://dx.doi.org/10.26421/qic17.15-16-4.

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We present an algorithm that takes a CSS stabilizer code as input, and outputs another CSS stabilizer code such that the stabilizer generators all have weights O(1) and such that O(1) generators act on any given qubit. The number of logical qubits is unchanged by the procedure, while we give bounds on the increase in number of physical qubits and in the effect on distance and other code parameters, such as soundness (as a locally testable code) and “cosoundness” (defined later). Applications are discussed, including to codes from high-dimensional manifolds which have logarithmic weight stabilizers. Assuming a conjecture in geometry[11], this allows the construction of CSS stabilizer codes with generator weight O(1) and almost linear distance. Another application of the construction is to increasing the distance to X or Z errors, whichever is smaller, so that the two distances are equal.
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Zhu, Bing. "Rethinking Fractional Repetition Codes: New Construction and Code Distance." IEEE Communications Letters 20, no. 2 (February 2016): 220–23. http://dx.doi.org/10.1109/lcomm.2015.2512871.

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Noguchi, Satoshi, Xiao-Nan Lu, Masakazu Jimbo, and Ying Miao. "BCH Codes with Minimum Distance Proportional to Code Length." SIAM Journal on Discrete Mathematics 35, no. 1 (January 2021): 179–93. http://dx.doi.org/10.1137/19m1260876.

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Talmale, Seema, Srija Unnikrishnan, and Bhaurao K. Lande. "Distance increasing mapping for variable distance block code." IET Communications 14, no. 9 (June 2, 2020): 1495–501. http://dx.doi.org/10.1049/iet-com.2019.0875.

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Dissertations / Theses on the topic "Code distance"

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Ketkar, Avanti Ulhas. "Code constructions and code families for nonbinary quantum stabilizer code." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/2743.

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Stabilizer codes form a special class of quantum error correcting codes. Nonbinary quantum stabilizer codes are studied in this thesis. A lot of work on binary quantum stabilizer codes has been done. Nonbinary stabilizer codes have received much less attention. Various results on binary stabilizer codes such as various code families and general code constructions are generalized to the nonbinary case in this thesis. The lower bound on the minimum distance of a code is nothing but the minimum distance of the currently best known code. The focus of this research is to improve the lower bounds on this minimum distance. To achieve this goal, various existing quantum codes are studied that have good minimum distance. Some new families of nonbinary stabilizer codes such as quantum BCH codes are constructed. Different ways of constructing new codes from the existing ones are also found. All these constructions together help improve the lower bounds.
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Miller, John. "High code rate, low-density parity-check codes with guaranteed minimum distance and stopping weight /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3090443.

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Filho, Nelson Whitaker. "Aircraft Distance Measurement System." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611674.

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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California
The Aircraft Distance Measurement System (ADMS) could be used in Flight Test application to determine the aircraft position and speed during takeoff, landing and acceleration-stop performance test within runway limits using a microwave link.
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Nordström, Markus. "Automatic Source Code Classification : Classifying Source Code for a Case-Based Reasoning System." Thesis, Mittuniversitetet, Avdelningen för informations- och kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-25519.

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This work has investigated the possibility of classifying Java source code into cases for a case-based reasoning system. A Case-Based Reasoning system is a problem solving method in Artificial Intelligence that uses knowledge of previously solved problems to solve new problems. A case in case-based reasoning consists of two parts: the problem part and solution part. The problem part describes a problem that needs to be solved and the solution part describes how this problem was solved. In this work, the problem is described as a Java source file using words that describes the content in the source file and the solution is a classification of the source file along with the source code. To classify Java source code, a classification system was developed. It consists of four analyzers: type filter, documentation analyzer, syntactic analyzer and semantic analyzer. The type filter determines if a Java source file contains a class or interface. The documentation analyzer determines the level of documentation in asource file to see the usefulness of a file. The syntactic analyzer extracts statistics from the source code to be used for similarity, and the semantic analyzer extracts semantics from the source code. The finished classification system is formed as a kd-tree, where the leaf nodes contains the classified source files i.e. the cases. Furthermore, a vocabulary was developed to contain the domain knowledge about the Java language. The resulting kd-tree was found to be imbalanced when tested, as the majority of source files analyzed were placed inthe left-most leaf nodes. The conclusion from this was that using documentation as a part of the classification made the tree imbalanced and thus another way has to be found. This is due to the fact that source code is not documented to such an extent that it would be useful for this purpose.
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Rivas, Angel Esteban Labrador. "Coordination of distance and overcurrent relays using a mathematical optimization technique." Universidade Estadual de Londrina. Centro de Tecnologia e Urbanismo. Programa de Pós-Graduação em Engenharia Elétrica, 2018. http://www.bibliotecadigital.uel.br/document/?code=vtls000218372.

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A proteção da rede de transmissão tem um papel importante nos sistemas de energia. Para melhorar a proteção é comum combinar diferentes tipos de relés; a combinação de relés de sobrecorrente e distância é um esquema bem conhecido. A lenta velocidade operacional do relé de sobrecorrente força a aplicação do relé de distância como o dispositivo de proteção principal. Os relés de sobrecorrente são usados como proteção de retaguarda tendo o esquema de distância como principal. Para atingir esse objetivo, a coordenação entre os sistemas de proteção primária e de retaguarda deve ser realizada desenvolvendo uma função objetivo com ambos parâmetros. Velocidade, seletividade e estabilidade são restrições, que devem ser satisfeitas através da coordenação. A coordenação do problema de relés direcionais de sobrecorrente (DOCRs) é um problema de programação não linear (NLP), geralmente resolvido com uma técnica de programação linear (LP) apenas considerando a configuração de tempo de atraso (TDS) como uma variável de decisão, sem lidar com o problema não-linear de configuração da corrente de partida (PS), ou com a resolução do componente PS usando uma técnica heurística. Um método meta-heurístico apresentado para resolver o problema de otimização é o algoritmo de otimização de colônias de formigas (ACO). O ACO empregado é uma extensão do algoritmo ACO para problemas de otimização de domínio contínuo implementados para problemas de otimização de variáveis mistas, condensados em dois tipos de variáveis tanto contínuas como categóricas. Neste trabalho, tanto o TDS como o PS são variáveis de decisão, o TDS é considerado contínuo e o PS categórico. Normalmente, a solução inicial é gerada aleatoriamente, além disso, esses resultados são comparados usando os mesmos valores aleatórios PS para resolver um relaxamento do problema DOCR com LP para obter novos valores TDS. A inclusão de relés de distância na formulação adicionará uma variável de tipo contínuo, mas com características lineares (constantes) que não alteram a formulação de DOCR para este problema de PNL. Para esta metodologia, cinco sistemas de transmissão (3, 6, 8, 9 e 15 Barras) foram avaliados para comparar a coordenação DOCR clássica, a introdução dos relés de distância e a resposta do modelo a soluções iniciais de alta qualidade junto a uma metodologia hibrida utilizando LP.
Protection of power transmission has an important role in power systems. To improve protection is common to combine different types of relays, which combination of overcurrent and distance relays is a well-known protection scheme. A slow operational speed of overcurrent relay forces application of distance relay as the main protection device. Overcurrent relays are used as backup protection to main distance protection system. To achieve this aim, coordination between primary and backup protection systems should be performed developing an objective function with both parameters. Speed, selectivity, and stability are constraints, which must be satisfied by performing coordination. The coordination of directional overcurrent relays (DOCRs) problem is a nonlinear programming problem (NLP), usually solved with a linear programming technique (LP) only considering the time dial setting (TDS) as a decision variable, without dealing with the non-linear problem of plug setting (PS), or solving the PS component using a heuristic technique. A metaheuristic algorithm method presented to solve the optimization problem is an ant colony optimization (ACO) algorithm. The ACO used is an extension of the ACO algorithm for continuous domain optimization problems implemented to mixed variable optimization problems, condensed in two types of variables both continuous and categorical. In this work, both TDS and PS are decision variables, TDS is considered continuous and PS categorical. Normally, the initial solution is random generated, in addition, those results are compared by using the same random PS values for solving a relaxation of the DOCRs problem with LP to obtain new TDS values. Including distance relays in the formulation will add an additional variable continuous type, but with linear (barely constant) characteristics making no changes in DOCRs formulation for this NLP problem. For this methodology, five transmission systems (3, 6, 8, 9, and 15 Bus accordingly) were evaluated to compare classical DOCR coordination, distance relays introduction and model response to high-quality initial solutions within a hybrid method using LP.
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Toste, Marisa Lapa. "Distance properties of convolutional codes over Z pr." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17953.

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Doutoramento em Matemática e Aplicações
Nesta tese consideramos códigos convolucionais sobre o anel polinomial [ ] r p ′ D , onde p é primo e r é um inteiro positivo. Em particular, focamo-nos no conjunto das palavras de código com suporte finito e estudamos as suas propriedades no que respeita às distâncias. Investigamos as duas propriedades mais importantes dos códigos convolucionais, nomeadamente, a distância livre e a distância de coluna. Começamos por analisar e solucionar o problema de, dado um conjunto de parâmetros, determinar a distância livre máxima possível que um código convolucional sobre [ ] r p ′ D pode atingir. Com efeito, obtemos um novo limite superior para esta distância generalizando os limites obtidos no contexto dos códigos convolucionais sobre corpos finitos. Além disso, mostramos que esse limite é ótimo, no sentido em que não pode ser melhorado. Para tal, apresentamos construções de códigos convolucionais (não necessariamente livres) que permitem atingir esse limite, para um certo conjunto de parâmetros. De acordo com a literatura chamamos a esses códigos MDS. Definimos também distâncias de coluna de um código convolucional. Obtemos limites superiores para as distâncias de coluna e chamamos MDP aos códigos cujas distâncias de coluna atingem estes limites superiores. Além disso, mostramos a existência de códigos MDP. Note-se, porém, que os códigos MDP apresentados não são completamente gerais pois os seus parâmetros devem satisfazer determinadas condições. Finalmente, estudamos o código dual de um código convolucional definido em (( )) r p ′ D . Os códigos duais de códigos convolucionais sobre corpos finitos foram exaustivamente investigados, como é refletido na literatura sobre o tema. Estes códigos são relevantes pois fornecem informação sobre a distribuição dos pesos do código e é neste sentido a inclusão deste assunto no âmbito desta tese. Outra razão importante para o estudo de códigos duais é a sua utilidade para o desenvolvimento de algoritmos de descodificação quando consideramos um erasure channel. Nesta tese são analisadas algumas propriedades fundamentais dos duais. Em particular, mostramos que códigos convolucionais definidos em (( )) r p ′ D admitem uma matriz de paridade. Para além disso, apresentamos um método construtivo para determinar um codificador de um código dual. keywords Convolutional codes, finite rings, free distance, column distance, MDS, MDP, dual code abstract In this thesis we consider convolutional codes over the polynomial ring [ ] r p ′ D , where p is a prime and r is a positive integer. In particular, we focus in the set of finite support codewords and study their distances properties. We investigate the two most important distance properties of convolutional codes, namely, the free distance and the column distance. First we address and fully solve the problem of determining the maximum possible free distance a convolutional code over [ ] r p ′ D can achieve, for a given set of parameters. Indeed, we derive a new upper bound on this distance generalizing the Singleton-type bounds derived in the context of convolutional codes over finite fields. Moreover, we show that such a bound is optimal in the sense that it cannot be improved. To do so we provide concrete constructions of convolutional codes (not necessarily free) that achieve this bound for any given set of parameters. In accordance with the literature we called such codes Maximum Distance Separable (MDS). We define the notion of column distance of a convolutional code. We obtain upper-bounds on the column distances and call Maximum Distance Profile (MDP) the codes that attain the maximum possible column distances. Furthermore, we show the existence of MDP codes. We note however that the MDP codes presented here are not completely general as their parameters need to satisfy certain conditions. Finally, we study the dual code of a convolutional code defined in (( )) r p ′ D . Dual codes of convolutional codes over finite fields have been thoroughly investigated as it is reflected in the large body of literature on this topic. They are relevant as they provide value information on the weight distribution of the code and therefore fit in the scope of this thesis. Another important reason for the study of dual codes is that they can be very useful for the development of decoding algorithms of convolutional codes over the erasure channel. In this thesis some fundamental properties have been analyzed. In particular, we show that convolutional codes defined in (( )) r p ′ D admit a parity-check matrix. Moreover, we
In this thesis we consider convolutional codes over the polynomial ring [ ] r p ′ D , where p is a prime and r is a positive integer. In particular, we focus in the set of finite support codewords and study their distances properties. We investigate the two most important distance properties of convolutional codes, namely, the free distance and the column distance. First we address and fully solve the problem of determining the maximum possible free distance a convolutional code over [ ] r p ′ D can achieve, for a given set of parameters. Indeed, we derive a new upper bound on this distance generalizing the Singleton-type bounds derived in the context of convolutional codes over finite fields. Moreover, we show that such a bound is optimal in the sense that it cannot be improved. To do so we provide concrete constructions of convolutional codes (not necessarily free) that achieve this bound for any given set of parameters. In accordance with the literature we called such codes Maximum Distance Separable (MDS). We define the notion of column distance of a convolutional code. We obtain upper-bounds on the column distances and call Maximum Distance Profile (MDP) the codes that attain the maximum possible column distances. Furthermore, we show the existence of MDP codes. We note however that the MDP codes presented here are not completely general as their parameters need to satisfy certain conditions. Finally, we study the dual code of a convolutional code defined in (( )) r p ′ D . Dual codes of convolutional codes over finite fields have been thoroughly investigated as it is reflected in the large body of literature on this topic. They are relevant as they provide value information on the weight distribution of the code and therefore fit in the scope of this thesis. Another important reason for the study of dual codes is that they can be very useful for the development of decoding algorithms of convolutional codes over the erasure channel. In this thesis some fundamental properties have been analyzed. In particular, we show that convolutional codes defined in (( )) r p ′ D admit a parity-check matrix. Moreover, we provide a constructive method to explicitly compute an encoder of the dual code.
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Papadimitriou, Panayiotis D. "Code design based on metric-spectrum and applications." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1365.

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We introduced nested search methods to design (n, k) block codes for arbitrary channels by optimizing an appropriate metric spectrum in each iteration. For a given k, the methods start with a good high rate code, say k/(k + 1), and successively design lower rate codes up to rate k/2^k corresponding to a Hadamard code. Using a full search for small binary codes we found that optimal or near-optimal codes of increasing length can be obtained in a nested manner by utilizing Hadamard matrix columns. The codes can be linear if the Hadamard matrix is linear and non-linear otherwise. The design methodology was extended to the generic complex codes by utilizing columns of newly derived or existing unitary codes. The inherent nested nature of the codes make them ideal for progressive transmission. Extensive comparisons to metric bounds and to previously designed codes show the optimality or near-optimality of the new codes, designed for the fading and the additive white Gaussian noise channel (AWGN). It was also shown that linear codes can be optimal or at least meeting the metric bounds; one example is the systematic pilot-based code of rate k/(k + 1) which was proved to meet the lower bound on the maximum cross-correlation. Further, the method was generalized such that good codes for arbitrary channels can be designed given the corresponding metric or the pairwise error probability. In synchronous multiple-access schemes it is common to use unitary block codes to transmit the multiple users’ information, especially in the downlink. In this work we suggest the use of newly designed non-unitary block codes, resulting in increased throughput efficiency, while the performance is shown not to be substantially sacrificed. The non-unitary codes are again developed through suitable nested searches. In addition, new multiple-access codes are introduced that optimize certain criteria, such as the sum-rate capacity. Finally, the introduction of the asymptotically optimum convolutional codes for a given constraint length, reduces dramatically the search size for good convolutional codes of a certain asymptotic performance, and the consequences to coded code-division multiple access (CDMA) system design are highlighted.
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Kacan, Denis, and Darius Sidlauskas. "Information Visualization and Machine Learning Applied on Static Code Analysis." Thesis, Blekinge Tekniska Högskola, Avdelningen för programvarusystem, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3033.

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Software engineers will possibly never see the perfect source code in their lifetime, but they are seeing much better analysis tools for finding defects in software. The approaches used in static code analysis emerged from simple code crawling to usage of statistical and probabilistic frameworks. This work presents a new technique that incorporates machine learning and information visualization into static code analysis. The technique learns patterns in a program’s source code using a normalized compression distance and applies them to classify code fragments into faulty or correct. Since the classification frequently is not perfect, the training process plays an essential role. A visualization element is used in the hope that it lets the user better understand the inner state of the classifier making the learning process transparent. An experimental evaluation is carried out in order to prove the efficacy of an implementation of the technique, the Code Distance Visualizer. The outcome of the evaluation indicates that the proposed technique is reasonably effective in learning to differentiate between faulty and correct code fragments, and the visualization element enables the user to discern when the tool is correct in its output and when it is not, and to take corrective action (further training or retraining) interactively, until the desired level of performance is reached.
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Ménéxiadis, Géraldine. "Détection à grande distance et localisation du supersonique "Concorde" à partir de signaux infrasonores." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2008. http://tel.archives-ouvertes.fr/tel-00487912.

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L'objet de cette étude est la résolution d'un problème inverse inédit, à savoir la localisation d'un avion supersonique à partir de signaux acoustiques enregistrés par une station de mesure unique. La distance de l'aéronef à la station de mesure est a priori inconnue, mais peut varier de quelques dizaines à quelques centaines de kilomètres ou davantage. Les signaux exploités à l'occasion de ce travail se situent généralement dans la gamme infrasonore, au-dessous de 20 Hz voire de 10 Hz. L'ONERA ayant mené des campagnes de mesure en Bretagne lors des premiers vols commerciaux transatlantiques de l'avion Concorde, les premières exploitations ont consisté à reprendre les données de ces campagnes et à développer à cette occasion un code de propagation acoustique basé sur la théorie des rayons. Le code de l'ONERA existant SIMOUN a été adapté en trois dimensions pour pouvoir tenir compte de la météorologie réelle et a reçu un certain nombre d'aménagements, dont le calcul de l'atténuation acoustique en fonction de la fréquence et la prise en compte de la rotondité de la Terre dont la négligence aurait entraîné des erreurs importantes aux grandes distances. Le calcul de niveau acoustique étant peu significatif aux distances considérées, des méthodes inédites basées sur l'analyse spectrale ont été développées. Associées à une technique de goniométrie basée notamment sur le calcul des fonctions d'intercorrélation temporelles, elles nous permettent de localiser l'avion supersonique en gisement-distance. Une première méthode, valable jusqu'à 200 kilomètres environ, est basée sur la divergence en fonction de la distance à l'aéronef de l'onde de pression en N correspondant au bang sonique. Il en résulte une modification du spectre en arche caractéristique de cette onde qui peut être corrélée avec la distance de propagation sous réserve de connaître l'onde en N initialement émise, reliée à la vitesse et à la géométrie de l'avion. Une seconde méthode beaucoup plus générale consiste à évaluer l'augmentation de la pente du spectre de l'onde en N, sachant que l'absorption atmosphérique, proportionnelle à la distance parcourue, augmente avec la fréquence et que la dissipation des effets non-linéaires a également tendance à augmenter la pente du spectre du signal. Cette méthode semble convenir pour des distances comprises entre 200 et 1000 km environ et présente l'avantage d'être indépendante des caractéristiques de la source sonore. Afin de pallier aux limitations de cette méthode, principalement liées au rapport signal sur bruit, l'analyse de signaux enregistrés en Suède à 3000 km de l'avion suggère d'utiliser pour les très grandes distances une méthode basée sur la durée totale du signal. Cette durée augmente en effet avec la distance, en rapport avec le phénomène classique de "rumble" qui transforme en roulement de tonnerre le signal impulsionnel émis par un coup de foudre.
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Abbara, Mamdouh. "Turbo-codes quantiques." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00842327.

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L'idée des turbo-codes, construction très performante permettant l'encodage de l'information classique, ne pouvait jusqu'à présent pas être transposé au problème de l'encodage de l'information quantique. En effet, il subsistait des obstacles tout aussi théoriques que relevant de leur implémentation. A la version quantique connue de ces codes, on ne connaissait ni de résultat établissant une distance minimale infinie, propriété qui autorise de corriger un nombre arbitraire d'erreurs, ni de décodage itératif efficace, car les turbo-encodages quantiques, dits catastrophiques, propagent certaines erreurs lors d'un tel décodage et empêchent son bon fonctionnement. Cette thèse a permis de relever ces deux défis, en établissant des conditions théoriques pour qu'un turbo-code quantique ait une distance minimale infinie, et d'autre part, en exhibant une construction permettant au décodage itératif de bien fonctionner. Les simulations montrent alors que la classe de turbo-codes quantiques conçue est efficace pour transmettre de l'information quantique via un canal dépolarisant dont l'intensité de dépolarisation peut aller jusqu'à p = 0,145. Ces codes quantiques, de rendement constant, peuvent aussi bien être utilisés directement pour encoder de l'information quantique binaire, qu'être intégrés comme modules afin d'améliorer le fonctionnement d'autres codes tels que les LDPC quantiques.
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Books on the topic "Code distance"

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Ai shen mi ma: Min jian nian hua zhong de qian li yin yuan = The code of the god of love : long distance romantic in new year pictures. Hangzhou Shi: Zhejiang gu ji chu ban she, 2011.

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Coke stop in Emo: Adventures of a long-distance paddler. Toronto, Ont: Key Porter Books, 1995.

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Lizak, Pawel. Minimum distance bounds for linear codes over GF(3) and GF(4). Salford: University of Salford, 1992.

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Bullough, Edward. La distanza psichica come fattore artistico e principio estetico. [Palermo]: Centro internazionale studi di estetica, 1997.

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Kuznecov, Sergey, and Konstantin Rogozin. All of physics on your palm. Interactive reference. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/501810.

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This is a unique visual book created by the best techniques of modern education. It presents the basic laws and formulas for all sections of physics with a huge number of interactive additions, explanations, illustrations, charts, graphs, tables, and drawings, allowing you to learn the material more efficiently. A clear and concise style of writing focuses the reader's attention in the target material, and numerous exercises, control questions and tasks allow you to securely fix in the memory the knowledge. Additional materials for all sections of General physics course available to You on the Internet in ABS Znanium.com. Using your mobile device, scan the QR code and get it on your smartphone or tablet access to comprehensive information throughout the course of physics in the media formats. In addition, on the YouTube channels "Salisylate and Isminimal from rocky" (from "the Russian Creative Internet") hosted a large number of additional training materials and videos used in this book. Interactive Handbook is intended for use in the educational activities of teachers and students of technical specialties of full-time and distance learning forms, as well as students of technical schools and secondary schools.
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Jernigan, Jack D. An investigation of the utility and accuracy of the table of speed and stopping distances specified in the Code of Virginia. Charlottesville, Va: Virginia Transportation Research Council, 2001.

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Distant desire: Homoerotic codes and the subversion of the English novel in E.M. Forster's fiction. New York: P. Lang, 1996.

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Mario, Costa. L' estetica della comunicazione: Come il medium ha polverizzato il messaggio : sull'uso estetico della simultaneità a distanza. Roma: Castelvecchi, 1999.

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Mario, Costa. L' estetica della comunicazione: Come il medium ha polverizzato il messaggio : sull'uso estetico della simultaneità a distanza. Roma: Castelvecchi, 1999.

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Badon, Cristina, ed. «Ti lascio con la penna, non col cuore». Lettere di Eleonora Rinuccini al marito Neri dei principi Corsini. 1835-1858. Florence: Firenze University Press, 2012. http://dx.doi.org/10.36253/978-88-6655-132-4.

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Published here are two hundred of the approximately seven hundred unpublished letters that Eleonora Rinuccini, the last representative of her dynasty, wrote to her husband, Neri Corsini, Marquis of Lajatico. A daily correspondence over twenty-five years of a marriage lived mostly at a distance on account of his numerous political and administrative commitments and her family and social duties. The letters, which are conserved in the Corsini archive in Florence, bear witness among other things, to a marital relationship characterised by great affection. They also reveal to us a woman who was in many respects ahead of her time, in terms of her moral codes, her behaviour and her vision of society and the people who moved in it in the crucial years of the Italian Risorgimento.
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Book chapters on the topic "Code distance"

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Weik, Martin H. "distance code." In Computer Science and Communications Dictionary, 439. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_5367.

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Weik, Martin H. "minimum distance code." In Computer Science and Communications Dictionary, 1022. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_11566.

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Weik, Martin H. "unit-distance code." In Computer Science and Communications Dictionary, 1863. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_20446.

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Weik, Martin H. "reflected binary unit distance code." In Computer Science and Communications Dictionary, 1445. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_15830.

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Ju, Zhen-fei, Xiao-jiao Mao, Ning Li, and Yu-bin Yang. "Binary Code Learning via Iterative Distance Adjustment." In MultiMedia Modeling, 83–94. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-14445-0_8.

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Eppler, Eva Duran. "The dependency distance hypothesis for bilingual code-switching." In Linguistik Aktuell/Linguistics Today, 183–206. Amsterdam: John Benjamins Publishing Company, 2014. http://dx.doi.org/10.1075/la.215.09dur.

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Reichardt, Ben W. "Fault-Tolerance Threshold for a Distance-Three Quantum Code." In Automata, Languages and Programming, 50–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11786986_6.

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Sun, Feng-Wen, and Henk C. A. Tilborg. "Fast Bounded-Distance Decoding of the Nordstrom-Robinson Code." In Communications and Cryptography, 391–98. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2694-0_38.

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Jégou, Yvon. "Performance Analysis of Code Coupling on Long Distance High Bandwidth Network." In Euro-Par 2002 Parallel Processing, 753–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45706-2_105.

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Amrani, Ofer, Yair Be'ery, and Alexander Vardy. "Bounded-distance decoding of the Leech lattice and the Golay code." In Algebraic Coding, 236–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/3-540-57843-9_24.

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Conference papers on the topic "Code distance"

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Adzhemov, A. S. "Code Distance Table and its Application." In 2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF). IEEE, 2018. http://dx.doi.org/10.1109/weconf.2018.8604435.

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French, C. A. "Distance preserving run-length limited code." In International Magnetics Conference. IEEE, 1989. http://dx.doi.org/10.1109/intmag.1989.690317.

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Zhilin, Igor, Alexey Kreshchuk, and Victor Zyablov. "On the code distance of a woven block code construction." In 2017 IEEE International Symposium on Information Theory (ISIT). IEEE, 2017. http://dx.doi.org/10.1109/isit.2017.8006481.

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Svetlov, Michael S., Alexey A. Lvov, Dmitry V. Klenov, Igor S. Bagaev, and Marina K. Svetlova. "Inter-symbol Distance Generated by Code with Code Signal Feature." In 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus). IEEE, 2020. http://dx.doi.org/10.1109/eiconrus49466.2020.9039035.

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Zhang, Lei, Yongdong Zhang, Jinhu Tang, Ke Lu, and Qi Tian. "Binary Code Ranking with Weighted Hamming Distance." In 2013 IEEE Conference on Computer Vision and Pattern Recognition (CVPR). IEEE, 2013. http://dx.doi.org/10.1109/cvpr.2013.208.

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Dehkordi, Arezou Banitalebi, and Syed A. R. Abu-Bakar. "Iris code matching using adaptive Hamming distance." In 2015 IEEE International Conference on Signal and Image Processing Applications (ICSIPA). IEEE, 2015. http://dx.doi.org/10.1109/icsipa.2015.7412224.

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Lin, Zeqi, Junfeng Zhao, Yanzhen Zou, and Bing Xie. "Document Distance Estimation via Code Graph Embedding." In Internetware'17: The Eighth Asia-Pacific Symposium on Internetware. New York, NY, USA: ACM, 2017. http://dx.doi.org/10.1145/3131704.3131713.

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Dziabiola, Marta, Robert Steiner, Ralf Vetter, Daniel Norskov, and Dorothé Smit. "Qude: Exploring Tactile Code in Long-Distance Relationships." In TEI '22: Sixteenth International Conference on Tangible, Embedded, and Embodied Interaction. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3490149.3505583.

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Zhang, Xiangyu, Armand Navabi, and Suresh Jagannathan. "Alchemist: A Transparent Dependence Distance Profiling Infrastructure." In 2009 7th Annual IEEE/ACM International Symposium on Code Generation and Optimization (CGO). IEEE, 2009. http://dx.doi.org/10.1109/cgo.2009.15.

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Lyu, Chong Woon, Bang Chul Jung, Sung Ho Moon, and Dan Keun Sung. "Distance-Based Code-Collision Control Scheme Using Erasure Decoding in Orthogonal Code Hopping Multiplexing." In The 9th International Conference on Advanced Communication Technology. IEEE, 2007. http://dx.doi.org/10.1109/icact.2007.358539.

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Reports on the topic "Code distance"

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McCaffrey, Trevor, and Gordon T. Richards. CIV Distance. GitHub, October 2021. http://dx.doi.org/10.17918/civdistance.

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LaChance, Jeffrey L., William G. Houf, Larry Fluer, and Bobby Middleton. Analyses to support development of risk-informed separation distances for hydrogen codes and standards. Office of Scientific and Technical Information (OSTI), March 2009. http://dx.doi.org/10.2172/983689.

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Mosiane, Ngaka, and Jennifer Murray. Economic and commuting connections in the northern GCR. Gauteng City-Region Observatory, February 2022. http://dx.doi.org/10.36634/tdlt5932.

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This Map of the Month illustrates some of the ways through which the core areas of the Gauteng City-Region (GCR) are interconnected with their peripheries, including those that are outside the Gauteng Province, but are within commuting distance. The connections are drawn as straight lines from the start to end points, representing some of the regional flows of goods, services, and people (particularly workers). These flows signify disparate types of relationships between the city region peripheries and core areas, involving the transporting of mining supplies from Gauteng to Rustenburg mining operations. They also indicate relationships of interdependence, including daily commutes from northern Tshwane and former KwaNdebele to the City of Tshwane. It suggests that, the railway lines, highways, and roads are among the government's most important development interventions. The resultant large-scale practices and spaces of mobility may be seen to overcome the divide between the core and periphery.
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Díaz de Astarloa, Bernardo, Nanno Mulder, Sandra Corcuera-Santamaría, Winfried Weck, Lucas Barreiros, Rodrigo Contreras Huerta, and Alejandro Puente. Post Pandemic Covid-19 Economic Recovery: Enabling Latin America and the Caribbean to Better Harness E-commerce and Digital Trade. Edited by Marcee Gómez. Inter-American Development Bank, August 2021. http://dx.doi.org/10.18235/0003436.

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This report shows that Latin America and the Caribbean faces critical policy challenges going forward. It must accelerate the digital transformation to allow businesses and consumers to adapt to a new normal and leverage pandemic recovery to create stronger economies, and also tackle long-standing barriers to adopting digital technologies and bridging digital divides. These have impeded sustained and equitable economic growth even before the pandemic struck. This crisis should be a wake-up call for governments, the private sector, civil society, and international development partners to come together and take concerted actions to advance on consistent, long-term, and sustainable e-commerce strategies that are at the forefront of national and regional productive development agendas. Just as digital solutions allowed countries to overcome the increased role of distance within the context of the pandemic in shaping consumption and business, they should also be harnessed to increase regional economic integration beyond this emergency situation.
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Savchenko, Sergii V., Svitlana O. Shekhavtsova, and Vladimir I. Zaselskiy. The development of students' critical thinking in the context of information security. [б. в.], November 2020. http://dx.doi.org/10.31812/123456789/4420.

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The problem of students’ critical thinking development in the context of information security becomes important in international and national educational policies as a means of fostering active citizenship and in turn sustainable development. The purpose of the given research is to introduce theoretical substantiation and experimental approbation of students’ critical thinking development in the context of information security. The skills of critical thinking help students to cope with the bulk of information they daily receive. However, there is still no conventional methodology for critical thinking development in university students. In our study we suggest possible ways to develop critical thinking in university students via introducing some special courses into the curriculum, and consider the results of the experimental study conducted on the basis of two Ukrainian leading universities. In order to improve the students’ skills of critical thinking the author suggested implementing the special course “The specifics of students’ critical thinking in the context of information security”, and an optional distance course on optimization of students’ critical thinking on the background of information and communication technologies. After the implementation of the suggested courses the indicators of students’ critical thinking development showed positive changes and proved the efficiency of the special courses as well as the general hypothesis of the study.
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Farahbod, A. M., and J. F. Cassidy. An overview of seismic attenuation in the Northern Appalachians Seismic Zone, New Brunswick and Nova Scotia. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329702.

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In this study we investigated coda-wave attenuation (QC) from the northern Appalachian region of eastern Canada in the two provinces of New Brunswick and Nova Scotia. We used earthquake recordings from 8 broadband and 2 short period seismograph stations of the Canadian National Seismograph Network (CNSN) across the region. Our dataset is comprised of 476 earthquakes recorded between 1983 and 2021 with magnitudes ranging from 1.5 to 4.1, depths from 0 to 20 km (with the vast majority being &amp;lt;10 km) and epicentral distances of 5 to 100 km. This gives a total of 261 high signalto- noise (S/N) traces (S/N greater than or equal to 5.0) useful for QC calculation (with a maximum ellipse parameter, a2, of 100) across the region. Coda windows were selected to start at tc = 2tS (two times the travel time of the direct S wave), and were filtered at center frequencies of 2, 4, 8, 12 and 16 Hz. Our study reveals a consistent pattern. We find that in the northern New Brunswick, the lowest Q0 values (e.g., Q0 of 61) are at station KLN which is the closest station to the epicenter of the 1982 Miramichi earthquake (M 5.8). The highest Q0 values that we find (e.g., Q0 of 178) are at station GGN, located in the southern New Brunswick. Smaller Q0 values for stations in the north (closer to the Charlevoix-Kamouraska seismic zone or Miramichi source area) is explained by Jin and Aki's (1988) finding that Q0 is lower in the vicinity of large earthquakes. An average for all the data results in a Q relationship of QC = 99f0.96 for the frequency band of 2 to 16 Hz for the entire region.
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Grumet, Rebecca, and Benjamin Raccah. Identification of Potyviral Domains Controlling Systemic Infection, Host Range and Aphid Transmission. United States Department of Agriculture, July 2000. http://dx.doi.org/10.32747/2000.7695842.bard.

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Potyviruses form one of the largest and most economically important groups of plant viruses. Individual potyviruses and their isolates vary in symptom expression, host range, and ability to overcome host resistance genes. Understanding factors influencing these biological characteristics is of agricultural importance for epidemiology and deployment of resistance strategies. Cucurbit crops are subject to severe losses by several potyviruses including the highly aggressive and variable zucchini yellow mosaic virus (ZYMV). In this project we sought to investigate protein domains in ZYMV that influence systemic infection and host range. Particular emphasis was on coat protein (CP), because of known functions in both cell to cell and long distance movement, and helper component-protease (HC-Pro), which has been implicated to play a role in symptom development and long distance movement. These two genes are also essential for aphid mediated transmission, and domains that influence disease development may also influence transmissibility. The objectives of the approved BARD project were to test roles of specific domains in the CP and HC-Pro by making sequence alterations or switches between different isolates and viruses, and testing for infectivity, host range, and aphid transmissibility. These objectives were largely achieved as described below. Finally, we also initiated new research to identify host factors interacting with potyviral proteins and demonstrated interaction between the ZYMV RNA dependent RNA polymerase and host poly-(A)-binding protein (Wang et al., in press). The focus of the CP studies (MSU) was to investigate the role of the highly variable amino terminus (NT) in host range determination and systemic infection. Hybrid ZYMV infectious clones were produced by substituting the CP-NT of ZYMV with either the CP-NT from watermelon mosaic virus (overlapping, but broader host range) or tobacco etch virus (TEV) (non- overlapping host range) (Grumet et al., 2000; Ullah ct al., in prep). Although both hybrid viruses initially established systemic infection, indicating that even the non-cucurbit adapted TEV CP-NT could facilitate long distance transport in cucurbits, after approximately 4-6, the plants inoculated with the TEV-CPNT hybrid exhibited a distinct recovery of reduced symptoms, virus titer, and virus specific protection against secondary infection. These results suggest that the plant recognizes the presence of the TEV CP-NT, which has not been adapted to infection of cucurbits, and initiates defense responses. The CP-NT also appears to play a role in naturally occurring resistance conferred by the zym locus in the cucumber line 'Dina-1'. Patterns of virus accumulation indicated that expression of resistance is developmentally controlled and is due to a block in virus movement. Switches between the core and NT domains of ZYMV-NAA (does not cause veinal chlorosis on 'Dina-1'), and ZYMV-Ct (causes veinal chlorosis), indicated that the resistance response likely involves interaction with the CP-NT (Ullah and Grumet, submitted). At the Volcani Center the main thrust was to identify domains in the HC-Pro that affect symptom expression or aphid transmissibility. From the data reported in the first and second year report and in the attached publications (Peng et al. 1998; Kadouri et al. 1998; Raccah et al. 2000: it was shown that: 1. The mutation from PTK to PAK resulted in milder symptoms of the virus on squash, 2. Two mutations, PAK and ATK, resulted in total loss of helper activity, 3. It was established for the first time that the PTK domain is involved in binding of the HC-Pro to the potyvirus particle, and 4. Some of these experiments required greater amount of HC-Pro, therefore a simpler and more efficient purification method was developed based on Ni2+ resin.
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Gur, Amit, Edward Buckler, Joseph Burger, Yaakov Tadmor, and Iftach Klapp. Characterization of genetic variation and yield heterosis in Cucumis melo. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7600047.bard.

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Project objectives: 1) Characterization of variation for yield heterosis in melon using Half-Diallele (HDA) design. 2) Development and implementation of image-based yield phenotyping in melon. 3) Characterization of genetic, epigenetic and transcriptional variation across 25 founder lines and selected hybrids. The epigentic part of this objective was modified during the course of the project: instead of characterization of chromatin structure in a single melon line through genome-wide mapping of nucleosomes using MNase-seq approach, we took advantage of rapid advancements in single-molecule sequencing and shifted the focus to Nanoporelong-read sequencing of all 25 founder lines. This analysis provides invaluable information on genome-wide structural variation across our diversity 4) Integrated analyses and development of prediction models Agricultural heterosis relates to hybrids that outperform their inbred parents for yield. First generation (F1) hybrids are produced in many crop species and it is estimated that heterosis increases yield by 15-30% globally. Melon (Cucumismelo) is an economically important species of The Cucurbitaceae family and is among the most important fleshy fruits for fresh consumption Worldwide. The major goal of this project was to explore the patterns and magnitude of yield heterosis in melon and link it to whole genome sequence variation. A core subset of 25 diverse lines was selected from the Newe-Yaar melon diversity panel for whole-genome re-sequencing (WGS) and test-crosses, to produce structured half-diallele design of 300 F1 hybrids (MelHDA25). Yield variation was measured in replicated yield trials at the whole-plant and at the rootstock levels (through a common-scion grafted experiments), across the F1s and parental lines. As part of this project we also developed an algorithmic pipeline for detection and yield estimation of melons from aerial-images, towards future implementation of such high throughput, cost-effective method for remote yield evaluation in open-field melons. We found extensive, highly heritable root-derived yield variation across the diallele population that was characterized by prominent best-parent heterosis (BPH), where hybrids rootstocks outperformed their parents by 38% and 56 % under optimal irrigation and drought- stress, respectively. Through integration of the genotypic data (~4,000,000 SNPs) and yield analyses we show that root-derived hybrids yield is independent of parental genetic distance. However, we mapped novel root-derived yield QTLs through genome-wide association (GWA) analysis and a multi-QTLs model explained more than 45% of the hybrids yield variation, providing a potential route for marker-assisted hybrid rootstock breeding. Four selected hybrid rootstocks are further studied under multiple scion varieties and their validated positive effect on yield performance is now leading to ongoing evaluation of their commercial potential. On the genomic level, this project resulted in 3 layers of data: 1) whole-genome short-read Illumina sequencing (30X) of the 25 founder lines provided us with 25 genome alignments and high-density melon HapMap that is already shown to be an effective resource for QTL annotation and candidate gene analysis in melon. 2) fast advancements in long-read single-molecule sequencing allowed us to shift focus towards this technology and generate ~50X Nanoporesequencing of the 25 founders which in combination with the short-read data now enable de novo assembly of the 25 genomes that will soon lead to construction of the first melon pan-genome. 3) Transcriptomic (3' RNA-Seq) analysis of several selected hybrids and their parents provide preliminary information on differentially expressed genes that can be further used to explain the root-derived yield variation. Taken together, this project expanded our view on yield heterosis in melon with novel specific insights on root-derived yield heterosis. To our knowledge, thus far this is the largest systematic genetic analysis of rootstock effects on yield heterosis in cucurbits or any other crop plant, and our results are now translated into potential breeding applications. The genomic resources that were developed as part of this project are putting melon in the forefront of genomic research and will continue to be useful tool for the cucurbits community in years to come.
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Alchanatis, Victor, Stephen W. Searcy, Moshe Meron, W. Lee, G. Y. Li, and A. Ben Porath. Prediction of Nitrogen Stress Using Reflectance Techniques. United States Department of Agriculture, November 2001. http://dx.doi.org/10.32747/2001.7580664.bard.

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Commercial agriculture has come under increasing pressure to reduce nitrogen fertilizer inputs in order to minimize potential nonpoint source pollution of ground and surface waters. This has resulted in increased interest in site specific fertilizer management. One way to solve pollution problems would be to determine crop nutrient needs in real time, using remote detection, and regulating fertilizer dispensed by an applicator. By detecting actual plant needs, only the additional nitrogen necessary to optimize production would be supplied. This research aimed to develop techniques for real time assessment of nitrogen status of corn using a mobile sensor with the potential to regulate nitrogen application based on data from that sensor. Specifically, the research first attempted to determine the system parameters necessary to optimize reflectance spectra of corn plants as a function of growth stage, chlorophyll and nitrogen status. In addition to that, an adaptable, multispectral sensor and the signal processing algorithm to provide real time, in-field assessment of corn nitrogen status was developed. Spectral characteristics of corn leaves reflectance were investigated in order to estimate the nitrogen status of the plants, using a commercial laboratory spectrometer. Statistical models relating leaf N and reflectance spectra were developed for both greenhouse and field plots. A basis was established for assessing nitrogen status using spectral reflectance from plant canopies. The combined effect of variety and N treatment was studied by measuring the reflectance of three varieties of different leaf characteristic color and five different N treatments. The variety effect on the reflectance at 552 nm was not significant (a = 0.01), while canonical discriminant analysis showed promising results for distinguishing different variety and N treatment, using spectral reflectance. Ambient illumination was found inappropriate for reliable, one-beam spectral reflectance measurement of the plants canopy due to the strong spectral lines of sunlight. Therefore, artificial light was consequently used. For in-field N status measurement, a dark chamber was constructed, to include the sensor, along with artificial illumination. Two different approaches were tested (i) use of spatially scattered artificial light, and (ii) use of collimated artificial light beam. It was found that the collimated beam along with a proper design of the sensor-beam geometry yielded the best results in terms of reducing the noise due to variable background, and maintaining the same distance from the sensor to the sample point of the canopy. A multispectral sensor assembly, based on a linear variable filter was designed, constructed and tested. The sensor assembly combined two sensors to cover the range of 400 to 1100 nm, a mounting frame, and a field data acquisition system. Using the mobile dark chamber and the developed sensor, as well as an off-the-shelf sensor, in- field nitrogen status of the plants canopy was measured. Statistical analysis of the acquired in-field data showed that the nitrogen status of the com leaves can be predicted with a SEP (Standard Error of Prediction) of 0.27%. The stage of maturity of the crop affected the relationship between the reflectance spectrum and the nitrogen status of the leaves. Specifically, the best prediction results were obtained when a separate model was used for each maturity stage. In-field assessment of the nitrogen status of corn leaves was successfully carried out by non contact measurement of the reflectance spectrum. This technology is now mature to be incorporated in field implements for on-line control of fertilizer application.
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Prusky, Dov, Nancy P. Keller, and Amir Sherman. global regulation of mycotoxin accumulation during pathogenicity of Penicillium expansum in postharvest fruits. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7600012.bard.

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Background to the topic- Penicilliumas a postharvest pathogen and producer of the mycotoxin PAT. Penicilliumspp. are destructive phytopathogens, capable of causing decay in many deciduous fruits, during postharvest handling and storage; and the resulting losses can amount to 10% of the stored produce and the accumulation of large amounts of the mycotoxinpatulin. The overall goal of this proposal is to identify critical host and pathogen factors that modulate P. expansummycotoxin genes and pathways which are required for PAT production and virulence. Our preliminary results indicated that gluconic acid are strongly affecting patulin accumulation during colonization. P. expansumacidifies apple fruit tissue during colonization in part through secretion of gluconic acid (GLA). Several publications suggested that GLA accumulation is an essential factor in P. expansumpathogenicity. Furthermore, down regulation of GOX2 significantly reduced PAT accumulation and pathogenicity. PAT is a polyketide and its biosynthesis pathway includes a 15-gene cluster. LaeA is a global regulator of mycotoxin synthesis. It is now known that patulin synthesis might be subjected to LaeA and sometimes by environmental sensing global regulatory factors including the carbon catabolite repressor CreA as well as the pH regulator factor PacC and nitrogen regulator AreA. The mechanisms by which LaeA regulates patulin synthesis was not fully known and was part of our work. Furthermore, the regulatory system that controls gene expression in accordance with ambient pH was also included in our work. PacC protein is in an inactive conformation and is unable to bind to the promoter sites of the target genes; however, under alkaline growth conditions activated PacC acts as both an activator of alkaline-expressed genes and a repressor of acid-expressed genes. The aims of the project- This project aims to provide new insights on the roles of LaeA and PacC and their signaling pathways that lead to GLA and PAT biosynthesis and pathogenicity on the host. Specifically, our specific aims were: i) To elucidate the mechanism of pH-controlled regulation of GLA and PAT, and their contribution to pathogenesis of P. expansum. We are interested to understanding how pH and/or GLA impact/s under PacC regulation affect PAT production and pathogenesis. ii) To characterize the role of LaeA, the global regulator of mycotoxin production, and its effect on PAT and PacC activity. iii) To identify the signaling pathways leading to GLA and PAT synthesis. Using state- of-the-art RNAseq technologies, we will interrogate the transcriptomes of laeAand pacCmutants, to identify the common signaling pathways regulating synthesis of both GLA and PAT. Major conclusions, solutions, achievements- In our first Aim our results demonstrated that ammonia secreted at the leading edge of the fungal colony induced transcript activation of the global pH modulator PacC and PAT accumulation in the presence of GLA. We assessed these parameters by: (i) direct exogenous treatment of P. expansumgrowing on solid medium; (ii) direct exogenous treatment on colonized apple tissue; (iii) growth under self-ammonia production conditions with limited carbon; and (iv) analysis of the transcriptional response to ammonia of the PAT biosynthesis cluster. Ammonia induced PAT accumulation concurrently with the transcript activation of pacCand PAT biosynthesis cluster genes, indicating the regulatory effect of ammonia on pacCtranscript expression under acidic conditions. Transcriptomic analysis of pH regulated processes showed that important genes and BARD Report - Project 4773 Page 2 of 10 functionalities of P. expansumwere controlled by environmental pH. The differential expression patterns of genes belonging to the same gene family suggest that genes were selectively activated according to their optimal environmental conditions to enable the fungus to cope with varying conditions and to make optimal use of available enzymes. Concerning the second and third Aims, we demonstrated that LaeA regulates several secondary metabolite genes, including the PAT gene cluster and concomitant PAT synthesis invitro. Virulence studies of ΔlaeAmutants of two geographically distant P. expansumisolates (Pe-21 from Israel and Pe-T01 from China) showed differential reduction in disease severity in freshly harvested fruit ranging from no reduction for Ch-Pe-T01 strains in immature fruit to 15–25% reduction for both strains in mature fruit, with the ΔlaeAstrains of Is-Pe-21 always showing a greater loss in virulence. Results suggest the importance of LaeA regulation of PAT and other secondary metabolites on pathogenicity. Our work also characterized for the first time the role of sucrose, a key nutritional factor present in apple fruit, as a negative regulator of laeAexpression and consequent PAT production in vitro. This is the first report of sugar regulation of laeAexpression, suggesting that its expression may be subject to catabolite repression by CreA. Some, but not all of the 54 secondary metabolite backbone genes in the P. expansumgenome, including the PAT polyketide backbone gene, were found to be regulated by LaeA. Together, these findings enable for the first time a straight analysis of a host factor that potentially activates laeAand subsequent PAT synthesis.
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