Literatura científica selecionada sobre o tema "Graphe de code"
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Artigos de revistas sobre o assunto "Graphe de code"
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Azkarate, Igor, Mikel Ayani, Juan Carlos Mugarza e Luka Eciolaza. "Petri Net-Based Semi-Compiled Code Generation for Programmable Logic Controllers". Applied Sciences 11, n.º 15 (3 de agosto de 2021): 7161. http://dx.doi.org/10.3390/app11157161.
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Industrial discrete event dynamic systems (DEDSs) are commonly modeled by means of Petri nets (PNs). PNs have the capability to model behaviors such as concurrency, synchronization, and resource sharing, compared to a step transition function chart or GRAphe Fonctionnel de Commande Etape Transition (GRAFCET) which is a particular case of a PN. However, there is not an effective systematic way to implement a PN in a programmable logic controller (PLC), and so the implementation of such a controller outside a PLC in some external software that will communicate with the PLC is very common. There have been some attempts to implement PNs within a PLC, but they are dependent on how the logic of places and transitions is programmed for each application. This work proposes a novel application-independent and platform-independent PN implementation methodology. This methodology is a systematic way to implement a PN controller within industrial PLCs. A great portion of the code will be validated automatically prior to PLC implementation. Net structure and marking evolution will be checked on the basis of PN model structural analysis, and only net interpretation will be manually coded and error-prone. Thus, this methodology represents a systematic and semi-compiled PN implementation method. A use case supported by a digital twin (DT) is shown where the automated solution required by a manufacturing system is carried out and executed in two different devices for portability testing, and the scan cycle periods are compared for both approaches.
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MÜLLER, T., e J. S. SERENI. "Identifying and Locating–Dominating Codes in (Random) Geometric Networks". Combinatorics, Probability and Computing 18, n.º 6 (11 de agosto de 2009): 925–52. http://dx.doi.org/10.1017/s0963548309990344.
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We model a problem about networks built from wireless devices using identifying and locating–dominating codes in unit disk graphs. It is known that minimizing the size of an identifying code is -complete even for bipartite graphs. First, we improve this result by showing that the problem remains -complete for bipartite planar unit disk graphs. Then, we address the question of the existence of an identifying code for random unit disk graphs. We derive the probability that there exists an identifying code as a function of the radius of the disks, and we find that for all interesting ranges of r this probability is bounded away from one. The results obtained are in sharp contrast to those concerning random graphs in the Erdős–Rényi model. Another well-studied class of codes is that of locating–dominating codes, which are less demanding than identifying codes. A locating–dominating code always exists, but minimizing its size is still -complete in general. We extend this result to our setting by showing that this question remains -complete for arbitrary planar unit disk graphs. Finally, we study the minimum size of such a code in random unit disk graphs, and we prove that with probability tending to one, it is of size (n/r)2/3+o(1) if r ≤ /2−ϵ is chosen such that nr2 → ∞, and of size n1+o(1) if nr2 ≪ lnn.
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Hudry, Olivier, Junnila Ville e Antoine Lobstein. "On Iiro Honkala’s Contributions to Identifying Codes". Fundamenta Informaticae 191, n.º 3-4 (22 de julho de 2024): 165–96. http://dx.doi.org/10.3233/fi-242178.
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A set C of vertices in a graph G = (V, E) is an identifying code if it is dominating and any two vertices of V are dominated by distinct sets of codewords. This paper presents a survey of Iiro Honkala’s contributions to the study of identifying codes with respect to several aspects: complexity of computing an identifying code, combinatorics in binary Hamming spaces, infinite grids, relationships between identifying codes and usual parameters in graphs, structural properties of graphs admitting identifying codes, and number of optimal identifying codes.
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Saenpholphat, Varaporn, e Ping Zhang. "Conditional resolvability in graphs: a survey". International Journal of Mathematics and Mathematical Sciences 2004, n.º 38 (2004): 1997–2017. http://dx.doi.org/10.1155/s0161171204311403.
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For an ordered setW={w1,w2,…,wk}of vertices and a vertexvin a connected graphG, the code ofvwith respect toWis thek-vectorcW(v)=(d(v,w1),d(v,w2),…,d(v,wk)), whered(x,y)represents the distance between the verticesxandy. The setWis a resolving set forGif distinct vertices ofGhave distinct codes with respect toW. The minimum cardinality of a resolving set forGis its dimensiondim(G). Many resolving parameters are formed by extending resolving sets to different subjects in graph theory, such as the partition of the vertex set, decomposition and coloring in graphs, or by combining resolving property with another graph-theoretic property such as being connected, independent, or acyclic. In this paper, we survey results and open questions on the resolving parameters defined by imposing an additional constraint on resolving sets, resolving partitions, or resolving decompositions in graphs.
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José, Marco, e Gabriel Zamudio. "Symmetrical Properties of Graph Representations of Genetic Codes: From Genotype to Phenotype". Symmetry 10, n.º 9 (8 de setembro de 2018): 388. http://dx.doi.org/10.3390/sym10090388.
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It has long been claimed that the mitochondrial genetic code possesses more symmetries than the Standard Genetic Code (SGC). To test this claim, the symmetrical structure of the SGC is compared with noncanonical genetic codes. We analyzed the symmetries of the graphs of codons and their respective phenotypic graph representation spanned by the RNY (R purines, Y pyrimidines, and N any of them) code, two RNA Extended codes, the SGC, as well as three different mitochondrial genetic codes from yeast, invertebrates, and vertebrates. The symmetry groups of the SGC and their corresponding phenotypic graphs of amino acids expose the evolvability of the SGC. Indeed, the analyzed mitochondrial genetic codes are more symmetrical than the SGC.
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Tang, C. S., e Tyng Liu. "The Degree Code—A New Mechanism Identifier". Journal of Mechanical Design 115, n.º 3 (1 de setembro de 1993): 627–30. http://dx.doi.org/10.1115/1.2919236.
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An important step in the structural synthesis of mechanisms requires the identification of isomorphism between the graphs which represents the mechanism topology. Previously used methods for identifying graph isomorphism either yield incorrect results for some cases or their algorithms are computationally inefficient for this application. This paper describes a new isomorphism identification method which is well suited for the automated structural synthesis of mechanisms. This method uses a new and compact mathematical representation for a graph, called the Degree Code, to identify graph isomorphism. Isomorphic graphs have identical Degree Codes; nonisomorphic graphs have distinct Degree Codes. Therefore, by examining the Degree Codes of the graphs, graph isomorphism is easily and correctly identified. This Degree Code algorithm is simpler and more efficient than other methods for identifying isomorphism correctly. In addition, the Degree Code can serve as an effective nomenclature and storage system for graphs or mechanisms. Although this identification scheme was developed specifically for the structural synthesis of mechanisms, it can be applied to any area where graph isomorphism is a critical issue.
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Leslie, Martin. "Hypermap-homology quantum codes". International Journal of Quantum Information 12, n.º 01 (fevereiro de 2014): 1430001. http://dx.doi.org/10.1142/s0219749914300010.
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We introduce a new type of sparse CSS quantum error correcting code based on the homology of hypermaps. Sparse quantum error correcting codes are of interest in the building of quantum computers due to their ease of implementation and the possibility of developing fast decoders for them. Codes based on the homology of embeddings of graphs, such as Kitaev's toric code, have been discussed widely in the literature and our class of codes generalize these. We use embedded hypergraphs, which are a generalization of graphs that can have edges connected to more than two vertices. We develop theorems and examples of our hypermap-homology codes, especially in the case that we choose a special type of basis in our homology chain complex. In particular the most straightforward generalization of the m × m toric code to hypermap-homology codes gives us a [(3/2)m2, 2, m] code as compared to the toric code which is a [2m2, 2, m] code. Thus we can protect the same amount of quantum information, with the same error-correcting capability, using less physical qubits.
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Schlingemann, D. "Stabilizer codes can be realized as graph codes". Quantum Information and Computation 2, n.º 4 (junho de 2002): 307–23. http://dx.doi.org/10.26421/qic2.4-4.
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We establish the connection between a recent new construction technique for quantum error correcting codes, based on graphs, and the so-called stabilizer codes: Each stabilizer code can be realized as a graph code and vice versa.
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Hwang, Yongsoo, e Jun Heo. "On the relation between a graph code and a graph state". Quantum Information and Computation 16, n.º 3&4 (março de 2016): 237–50. http://dx.doi.org/10.26421/qic16.3-4-3.
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A graph state and a graph code respectively are defined based on a mathematical simple graph. In this work, we examine a relation between a graph state and a graph code both obtained from the same graph, and show that a graph state is a superposition of logical qubits of the related graph code. By using the relation, we first discuss that a local complementation which has been used for a graph state can be useful for searching locally equivalent stabilizer codes, and second provide a method to find a stabilizer group of a graph code.
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Al-Kadhimi, Aymen M., Ammar E. Abdulkareem e Charalampos C. Tsimenidis. "Performance Enhancement of LDPC Codes Based on Protograph Construction in 5G-NR Standard". Tikrit Journal of Engineering Sciences 30, n.º 4 (1 de novembro de 2023): 1–10. http://dx.doi.org/10.25130/tjes.30.4.1.
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To meet the high throughput demands, the 3rd Generation Partnership Project has specified the low-density parity check (LDPC) codes in the fifth generation-new radio 5G-NR standard with rate and length compatibility and scalability. This paper presents an extensive performance evaluation and enhancement of LPDC using the protograph-based construction defined in the 5G-NR standard. Firstly, the protograph-LDPC with layered offset min-sum (OMS) decoding, polar with successive cancellation list (SCL), and block turbo code are implemented and compared. Puncturing and shortening are applied to maintain block length at 1024 and code rate at 1/2 for all codes for comparison fairness. The results showed that P-LDPC outperforms its counterparts in terms of bit/ frame error rate (BER/ FER) behavior for given signal-to-noise ratios. Then, different P-LDPC settings were realized to study the effects of base graph selection (Graph1 or Graph2), code rate change (1/3 - 2/3), and block lengths increase (260 – 4160 bits). The simulation outcomes proved that BER performed better for lower coding rates or higher block lengths. Furthermore, P-LDPC behavior was examined over a Rayleigh flat-fading channel to achieve a 12.5 dB coding gain at 0.001 BER compared with uncoded transmission.
Teses / dissertações sobre o assunto "Graphe de code"
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Bertrand, Sébastien. "Modèle de maintenabilité logicielle par analyse statique du graphe de code du programme". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0414.
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Le coût élevé de la maintenance des logiciels exige de travailler sur leur maintenabilité. Bien qu’émergente de la structure du code source, son évaluation est subjective, car elle dépend des développeurs et du contexte. Les modèles de maintenabilité actuels tendent à réduire la maintenabilité à un score unidimensionnel basé sur des métriques, souvent mal définies, qui représentent mal la structure du code. Nos travaux se sont basés sur l’analyse statique des graphes de code pour évaluer la maintenabilité. Ils ont permis de développer Javanalyser, un outil libre qui génère automatiquement le graphe de code d’un programme Java. Ces graphes ont permis de formaliser 33 métriques statiques sous forme de requêtes déclarative et ont permis de reproduire avec succès une étude de Schnappinger et al. Notre extension de l’étude confirme l’importance de la taille du programme comme facteur influençant la maintenabilité, sans toutefois négliger l’impact des autres métriques. Ce travail ouvre la voie à une compréhension plus approfondie de la maintenabilité, grâce à une représentation multidimensionnelle permettant de tenir compte de la variabilité entre les développeursThe high cost of software maintenance requires a focus on software maintainability. Although it emerges from the structure of the source code, its evaluation is subjective, as it depends on developers and the context. Current maintainability models tend to reduce maintainability to a one-dimensional score based on metrics, often poorly defined, which inadequately represent the structure of the code. Our work is based on the static analysis of code graphs to evaluate maintainability. It led to the development of Javanalyser, an open-source tool that automatically generates the code graph of a Java program. These graphs enabled the formalization of 33 static metrics as declarative queries, and allowed the successful replication of a study by Schnappinger et al. Our extension of the study confirmed the importance of size as a factor influencing maintainability, while also recognizing the impact of other metrics. This work opens the way to a deeper understanding of maintainability through a multidimensional representation that takes into account the variability between developers
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Roux, Antoine. "Etude d’un code correcteur linéaire pour le canal à effacements de paquets et optimisation par comptage de forêts et calcul modulaire". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS337.
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La transmission fiable de données sur un canal de transmission est un problème récurrent en Informatique. En effet, quel que soit le canal de transmission employé, on observe obligatoirement de la détérioration de l’information transmise, voire sa perte pure et simple. Afin de palier à ce problème, plusieurs solutions ont été apportées, notamment via l’emploi de codes correcteurs. Dans cette thèse, nous étudions un code correcteur développé en 2014 et 2015 pour l’entreprise Thales durant ma deuxième année de Master en apprentissage. Il s’agit d’un code actuellement utilisé par Thales pour fiabiliser une transmission UDP passant par un dispositif réseau, l’Elips-SD. L’Elips-SD est une diode réseau qu’on place sur une fibre optique et qui garantit physiquement que la transmission est unidirectionnelle. Le cas d’utilisation principal de cette diode est de permettre le suivi de la production d’un site sensible, ou encore de superviser son fonctionnement, tout en garantissant à ce site une protection face aux intrusions extérieures. A l’opposé, un autre cas d’utilisation est la transmission de données depuis un ou plusieurs sites non-sécurisés vers un site sécurisé, dont on souhaite s’assurer qu’aucune information ne pourra par la suite fuiter. Le code correcteur que nous étudions est un code correcteur linéaire pour le canal à effacements de paquets, qui a reçu la certification OTAN de la Direction Générale des Armées. Nous l’avons babtisé "Fauxtraut", anagramme de "Fast algorithm using Xor to repair altered unidirectionnal transmissions". Afin d’étudier ce code correcteur, de présenter son fonctionnement et ses performances, et les différentes modifications apportées durant cette thèse, nous établissons tout d’abord un état de l’art des codes correcteurs, en nous concentrant principalement sur les codes linéaires non-MDS, tels que les codes LDPC. Puis nous présentons le fonctionnement de Fauxtraut, et analysons son comportement (complexité, consommation mémoire, performances) par la théorie et par des simulations. Enfin, nous présenterons différentes versions de ce code correcteur développées durant cette thèse, qui aboutissent à d’autres cas d’utilisation, tels que la transmission d’information sur un canal unidirectionnel à erreurs ou sur un canal bidirectionnel, à l’image de ce que permet de faire le protocole H-ARQ. Dans cette partie, nous étudierons notamment le comportement de notre code correcteur via la théorie des graphes : calculer la probabilité de décoder convenablement ou non revient à connaître la probabilité d’apparition de cycles dans le sous-graphe de graphes particuliers, les graphes de Rook et les graphes bipartis complets. Le problème s’énonce simplement et s’avère compliqué, et nous espérons qu’il saura intéresser des chercheurs du domaine. Nous présentons une méthode permettant de calculer exactement cette probabilité pour de petits graphes (qui aboutit à un certain nombre de formules closes), et une fonction tendant asymptotiquement vers cette probabilité pour de plus grands graphes. Nous étudierons aussi la manière de paramétrer automatiquement notre code correcteur par le calcul modulaire et la combinatoire, utilisant la fonction de Landau, qui retourne un ensemble de nombres entiers dont la somme est fixée et le plus commun multiple est maximal. Dans une dernière partie, nous présentons un travail effectué durant cette thèse ayant conduit à une publication dans la revue Theoretical Computer Science. Il concerne un problème non-polynomial de la théorie des graphes : le couplage maximal dans les graphes temporels. Cet article propose notamment deux algorithmes de complexité polynomiale : un algorithme de 2-approximation et un algorithme de kernelisation pour ce problème. L’algorithme de 2- approximation peut notamment être utilisé de manière incrémentale : arêtes du flot de liens nous parviennent les unes après les autres, et on construit la 2-approximation au fur et à mesure de leur arrivéeReliably transmitting information over a transmission channel is a recurrent problem in Informatic Sciences. Whatever may be the channel used to transmit information, we automatically observe erasure of this information, or pure loss. Different solutions can be used to solve this problem, using forward error correction codes is one of them. In this thesis, we study a corrector code developped in 2014 and 2015 for Thales society during my second year of master of apprenticeship. It is currently used to ensure the reliability of a transmission based on the UDP protocole, and passing by a network diode, Elips-SD. Elip-SD is an optical diode that can be plugged on an optical fiber to physically ensure that the transmission is unidirectional. The main usecase of such a diode is to enable supervising a critical site, while ensuring that no information can be transmitted to this site. At the opposite, another usecase is the transmission from one or multiple unsecured emitters to one secured receiver who wants to ensure that no information can be robbed. The corrector code that we present is a linear corrector code for the binary erasure channel using packets, that obtained the NATO certification from the DGA ("Direction Générale de Armées" in French). We named it Fauxtraut, for "Fast algorithm using Xor to repair altered unidirectional transmissions". In order to study this code, presenting how it works, its performance and the modifications we added during this thesis, we first establish a state of the art of forward error correction, focusing on non-MDS linear codes such as LDPC codes. Then we present Fauxtraut behavior, and analyse it theorically and with simulations. Finally, we present different versions of this code that were developped during this thesis, leading to other usecases such as transmitting reliable information that can be altered instead of being erased, or on a bidirectionnal channel, such as the H-ARQ protocole, and different results on the number of cycles in particular graphs. In the last part, we present results that we obtained during this thesis and that finally lead to an article in the Technical Computer Science. It concerns a non-polynomial problema of Graphs theorie : maximum matching in temporal graphs. In this article, we propose two algorithms with polynomial complexity : a 2-approximation algorithm and a kernelisation algorithm forthis problema
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Richa, Elie. "Qualification des générateurs de code source dans le domaine de l'avionique : le test automatisé des chaines de transformation de modèles". Thesis, Paris, ENST, 2015. http://www.theses.fr/2015ENST0082/document.
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Dans l’industrie de l’avionique, les Générateurs Automatiques de Code (GAC) sont de plus en plus utilisés pour produire des parties du logiciel embarqué. Puisque le code généré fait partie d’un logiciel critique, les standards de sûreté exigent une vérification approfondie du GAC: la qualification. Dans cette thèse en collaboration avec AdaCore, nous cherchons à réduire le coût des activités de test par des méthodes automatiques et efficaces.La première partie de la thèse aborde le sujet du test unitaire qui assure une exhaustivité élevée mais qui est difficile à réaliser pour les GACs. Nous proposons alors une méthode qui garantit le même niveau d’exhaustivité en n’utilisant que des tests d’intégration de mise en œuvre plus facile. Nous proposons tout d’abord une formalisation du langage ATL de définition du GAC dans la théorie des Transformations Algébriques de Graphes. Nous définissons ensuite une traduction de postconditions exprimant l’exhaustivité du test unitaire en des préconditions équivalentes qui permettent à terme de produire des tests d’intégration assurant le même niveau d’exhaustivité. Enfin, nous proposons d’optimiser l’algorithme complexe de notre analyse à l’aide de stratégies de simplification dont nous mesurons expérimentalement l’efficacité.La seconde partie du travail concerne les oracles de tests du GAC, c’est à dire le moyen de valider le code généré par le GAC lors d’un test. Nous proposons un langage de spécification de contraintes textuelles capables d’attester automatiquement de la validité du code généré. Cette approche est déployée expérimentalement à AdaCore pour le projet QGen, un générateur de code Ada/C à partir de Simulink®In the avionics industry, Automatic Code Generators (ACG) are increasingly used to produce parts of the embedded software. Since the generated code is part of critical software, safety standards require a thorough verification of the ACG called qualification. In this thesis in collaboration with AdaCore, we seek to reduce the cost of testing activities by automatic and effective methods.The first part of the thesis addresses the topic of unit testing which ensures exhaustiveness but is difficult to achieve for ACGs. We propose a method that guarantees the same level of exhaustiveness by using only integration tests which are easier to carry out. First, we propose a formalization of the ATL language in which the ACG is defined in the Algebraic Graph Transformation theory. We then define a translation of postconditions expressing the exhaustiveness of unit testing into equivalent preconditions that ultimately support the production of integration tests providing the same level of exhaustiveness. Finally, we propose to optimize the complex algorithm of our analysis using simplification strategies that we assess experimentally.The second part of the work addresses the oracles of ACG tests, i.e. the means of validating the code generated by the ACG during a test. We propose a language for the specification of textual constraints able to automatically check the validity of the generated code. This approach is experimentally deployed at AdaCore for a Simulink® to Ada/C ACG called QGen
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Richa, Elie. "Qualification des générateurs de code source dans le domaine de l'avionique : le test automatisé des chaines de transformation de modèles". Electronic Thesis or Diss., Paris, ENST, 2015. http://www.theses.fr/2015ENST0082.
Texto completo da fonteResumo:
Dans l’industrie de l’avionique, les Générateurs Automatiques de Code (GAC) sont de plus en plus utilisés pour produire des parties du logiciel embarqué. Puisque le code généré fait partie d’un logiciel critique, les standards de sûreté exigent une vérification approfondie du GAC: la qualification. Dans cette thèse en collaboration avec AdaCore, nous cherchons à réduire le coût des activités de test par des méthodes automatiques et efficaces.La première partie de la thèse aborde le sujet du test unitaire qui assure une exhaustivité élevée mais qui est difficile à réaliser pour les GACs. Nous proposons alors une méthode qui garantit le même niveau d’exhaustivité en n’utilisant que des tests d’intégration de mise en œuvre plus facile. Nous proposons tout d’abord une formalisation du langage ATL de définition du GAC dans la théorie des Transformations Algébriques de Graphes. Nous définissons ensuite une traduction de postconditions exprimant l’exhaustivité du test unitaire en des préconditions équivalentes qui permettent à terme de produire des tests d’intégration assurant le même niveau d’exhaustivité. Enfin, nous proposons d’optimiser l’algorithme complexe de notre analyse à l’aide de stratégies de simplification dont nous mesurons expérimentalement l’efficacité.La seconde partie du travail concerne les oracles de tests du GAC, c’est à dire le moyen de valider le code généré par le GAC lors d’un test. Nous proposons un langage de spécification de contraintes textuelles capables d’attester automatiquement de la validité du code généré. Cette approche est déployée expérimentalement à AdaCore pour le projet QGen, un générateur de code Ada/C à partir de Simulink®In the avionics industry, Automatic Code Generators (ACG) are increasingly used to produce parts of the embedded software. Since the generated code is part of critical software, safety standards require a thorough verification of the ACG called qualification. In this thesis in collaboration with AdaCore, we seek to reduce the cost of testing activities by automatic and effective methods.The first part of the thesis addresses the topic of unit testing which ensures exhaustiveness but is difficult to achieve for ACGs. We propose a method that guarantees the same level of exhaustiveness by using only integration tests which are easier to carry out. First, we propose a formalization of the ATL language in which the ACG is defined in the Algebraic Graph Transformation theory. We then define a translation of postconditions expressing the exhaustiveness of unit testing into equivalent preconditions that ultimately support the production of integration tests providing the same level of exhaustiveness. Finally, we propose to optimize the complex algorithm of our analysis using simplification strategies that we assess experimentally.The second part of the work addresses the oracles of ACG tests, i.e. the means of validating the code generated by the ACG during a test. We propose a language for the specification of textual constraints able to automatically check the validity of the generated code. This approach is experimentally deployed at AdaCore for a Simulink® to Ada/C ACG called QGen
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Robillard, Benoît. "Verification formelle et optimisation de l’allocation de registres". Electronic Thesis or Diss., Paris, CNAM, 2010. http://www.theses.fr/2010CNAM0730.
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La prise de conscience générale de l'importance de vérifier plus scrupuleusement les programmes a engendré une croissance considérable des efforts de vérification formelle de programme durant cette dernière décennie. Néanmoins, le code qu'exécute l'ordinateur, ou code exécutable, n'est pas le code écrit par le développeur, ou code source. La vérification formelle de compilateurs est donc un complément indispensable à la vérification de code source.L'une des tâches les plus complexes de compilation est l'allocation de registres. C'est lors de celle-ci que le compilateur décide de la façon dont les variables du programme sont stockées en mémoire durant son exécution. La mémoire comporte deux types de conteneurs : les registres, zones d'accès rapide, présents en nombre limité, et la pile, de capacité supposée suffisamment importante pour héberger toutes les variables d'un programme, mais à laquelle l'accès est bien plus lent. Le but de l'allocation de registres est de tirer au mieux parti de la rapidité des registres, car une allocation de registres de bonne qualité peut conduire à une amélioration significative du temps d'exécution du programme.Le modèle le plus connu de l'allocation de registres repose sur la coloration de graphe d'interférence-affinité. Dans cette thèse, l'objectif est double : d'une part vérifier formellement des algorithmes connus d'allocation de registres par coloration de graphe, et d'autre part définir de nouveaux algorithmes optimisants pour cette étape de compilation. Nous montrons tout d'abord que l'assistant à la preuve Coq est adéquat à la formalisation d'algorithmes d'allocation de registres par coloration de graphes. Nous procédons ainsi à la vérification formelle en Coq d'un des algorithmes les plus classiques d'allocation de registres par coloration de graphes, l'Iterated Register Coalescing (IRC), et d'une généralisation de celui-ci permettant à un utilisateur peu familier du système Coq d'implanter facilement sa propre variante de cet algorithme au seul prix d'une éventuelle perte d'efficacité algorithmique. Ces formalisations nécessitent des réflexions autour de la formalisation des graphes d'interférence-affinité, de la traduction sous forme purement fonctionnelle d'algorithmes impératifs et de l'efficacité algorithmique, la terminaison et la correction de cette version fonctionnelle. Notre implantation formellement vérifiée de l'IRC a été intégrée à un prototype du compilateur CompCert.Nous avons ensuite étudié deux représentations intermédiaires de programmes, dont la forme SSA, et exploité leurs propriétés pour proposer de nouvelles approches de résolution optimale de la fusion, l'une des optimisations opéréeslors de l'allocation de registres dont l'impact est le plus fort sur la qualité du code compilé. Ces approches montrent que des critères de fusion tenant compte de paramètres globaux du graphe d'interférence-affinité, tels que sa largeur d'arbre, ouvrent la voie vers de nouvelles méthodes de résolution potentiellement plus performantesThe need for trustful programs led to an increasing use of formal verication techniques the last decade, and especially of program proof. However, the code running on the computer is not the source code, i.e. the one written by the developper, since it has to betranslated by the compiler. As a result, the formal verication of compilers is required to complete the source code verication. One of the hardest phases of compilation is register allocation. Register allocation is the phase within which the compiler decides where the variables of the program are stored in the memory during its execution. The are two kinds of memory locations : a limited number of fast-access zones, called registers, and a very large but slow-access stack. The aim of register allocation is then to make a great use of registers, leading to a faster runnable code.The most used model for register allocation is the interference graph coloring one. In this thesis, our objective is twofold : first, formally verifying some well-known interference graph coloring algorithms for register allocation and, second, designing new graph-coloring register allocation algorithms. More precisely, we provide a fully formally veri ed implementation of the Iterated Register Coalescing, a very classical graph-coloring register allocation heuristics, that has been integrated into the CompCert compiler. We also studied two intermediate representations of programs used in compilers, and in particular the SSA form to design new algorithms, using global properties of the graph rather than local criteria currently used in the litterature
6
Robillard, Benoît. "Verification formelle et optimisation de l’allocation de registres". Thesis, Paris, CNAM, 2010. http://www.theses.fr/2010CNAM0730/document.
Texto completo da fonteResumo:
La prise de conscience générale de l'importance de vérifier plus scrupuleusement les programmes a engendré une croissance considérable des efforts de vérification formelle de programme durant cette dernière décennie. Néanmoins, le code qu'exécute l'ordinateur, ou code exécutable, n'est pas le code écrit par le développeur, ou code source. La vérification formelle de compilateurs est donc un complément indispensable à la vérification de code source.L'une des tâches les plus complexes de compilation est l'allocation de registres. C'est lors de celle-ci que le compilateur décide de la façon dont les variables du programme sont stockées en mémoire durant son exécution. La mémoire comporte deux types de conteneurs : les registres, zones d'accès rapide, présents en nombre limité, et la pile, de capacité supposée suffisamment importante pour héberger toutes les variables d'un programme, mais à laquelle l'accès est bien plus lent. Le but de l'allocation de registres est de tirer au mieux parti de la rapidité des registres, car une allocation de registres de bonne qualité peut conduire à une amélioration significative du temps d'exécution du programme.Le modèle le plus connu de l'allocation de registres repose sur la coloration de graphe d'interférence-affinité. Dans cette thèse, l'objectif est double : d'une part vérifier formellement des algorithmes connus d'allocation de registres par coloration de graphe, et d'autre part définir de nouveaux algorithmes optimisants pour cette étape de compilation. Nous montrons tout d'abord que l'assistant à la preuve Coq est adéquat à la formalisation d'algorithmes d'allocation de registres par coloration de graphes. Nous procédons ainsi à la vérification formelle en Coq d'un des algorithmes les plus classiques d'allocation de registres par coloration de graphes, l'Iterated Register Coalescing (IRC), et d'une généralisation de celui-ci permettant à un utilisateur peu familier du système Coq d'implanter facilement sa propre variante de cet algorithme au seul prix d'une éventuelle perte d'efficacité algorithmique. Ces formalisations nécessitent des réflexions autour de la formalisation des graphes d'interférence-affinité, de la traduction sous forme purement fonctionnelle d'algorithmes impératifs et de l'efficacité algorithmique, la terminaison et la correction de cette version fonctionnelle. Notre implantation formellement vérifiée de l'IRC a été intégrée à un prototype du compilateur CompCert.Nous avons ensuite étudié deux représentations intermédiaires de programmes, dont la forme SSA, et exploité leurs propriétés pour proposer de nouvelles approches de résolution optimale de la fusion, l'une des optimisations opéréeslors de l'allocation de registres dont l'impact est le plus fort sur la qualité du code compilé. Ces approches montrent que des critères de fusion tenant compte de paramètres globaux du graphe d'interférence-affinité, tels que sa largeur d'arbre, ouvrent la voie vers de nouvelles méthodes de résolution potentiellement plus performantesThe need for trustful programs led to an increasing use of formal verication techniques the last decade, and especially of program proof. However, the code running on the computer is not the source code, i.e. the one written by the developper, since it has to betranslated by the compiler. As a result, the formal verication of compilers is required to complete the source code verication. One of the hardest phases of compilation is register allocation. Register allocation is the phase within which the compiler decides where the variables of the program are stored in the memory during its execution. The are two kinds of memory locations : a limited number of fast-access zones, called registers, and a very large but slow-access stack. The aim of register allocation is then to make a great use of registers, leading to a faster runnable code.The most used model for register allocation is the interference graph coloring one. In this thesis, our objective is twofold : first, formally verifying some well-known interference graph coloring algorithms for register allocation and, second, designing new graph-coloring register allocation algorithms. More precisely, we provide a fully formally veri ed implementation of the Iterated Register Coalescing, a very classical graph-coloring register allocation heuristics, that has been integrated into the CompCert compiler. We also studied two intermediate representations of programs used in compilers, and in particular the SSA form to design new algorithms, using global properties of the graph rather than local criteria currently used in the litterature
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Stange, Yuri. "Visualization of Code Flow". Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-162108.
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Visual representation of Control Flow Graphs (CFG) is a feature available in many tools, such as decompilers. These tools often rely on graph drawing frameworks which implement the Sugiyama hierarchical style graph drawing method, a well known method for drawing directed graphs. The main disadvantage of the Sugiyama framework, is the fact that it does not take into account the nature of the graph to be visualized, specically loops are treated as second class citizens. The question this paper attempts to answer is; how can we improve the visual representation of loops in the graph? A method based on the Sugiyama framework was developed and implemented in Qt. It was evaluated by informally interviewing test subjects, who were allowed to test the implementation and compare it to the normal Sugiyama. The results show that all test subjects concluded that loops, as well as the overall representation of the graph was improved, although with reservations. The method presented in this paper has problems which need to be adressed, before it can be seen as an optimal solution for drawing Control Flow Graphs.Visuell representation av flödesscheman (eng. Control Flow Graph, CFG) är en funktion tillgänglig hos många verktyg, bland annat dekompilerare. Dessa verktyg använder sig ofta av grafritande ramverk som implementerar Sugiyamas metod för uppritning av hierarkiska grafer, vilken är en känd metod för uppritning av riktade grafer. Sugiyamas stora nackdelär att metoden inte tar hänsyn till grafens natur, loopar i synnerhet behandlas som andra klassens medborgare. Frågeställningen hos denna rapport är; Hur kan vi förbättra den visuella representationen av loopar i en graf? En metod som bygger vidare på Sugiyama-ramverket utvecklades och implementerades i Qt. Metoden testades genom att hålla informella kvalitativa intervjuer med testpersoner, vilka fick testa implementeringen och jämföra den med den vanliga Sugiyama-metoden. Resultaten visar att alla testpersonerna stämmer in på att loopar, så väl som den overskådliga representionen av grafen förbättrades, dock med vissa reservationer. Metoden som presenteras i denna rapport har vissa problem, vilka bör adresseras innan den kan ses som en optimal lösning för uppritning av flödesscheman.
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Li, Chao. "Semidefinite programming, binary codes and a graph coloring problem". Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/863.
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"Experts in information theory have long been interested in the maximal size, A(n, d), of a binary error-correcting code of length n and minimum distance d, The problem of determining A(n, d) involves both the construction of good codes and the search for good upper bounds. For quite some time now, Delsarte's linear programming approach has been the dominant approach to obtaining the strongest general purpose upper bounds on the efficiency of error-correcting codes. From 1973 forward, the linear programming bound found many applications, but there were few significant theoretical advances until Schrijver proposed a new code upper bound via semidefinite programming in 2003. Using the Terwilliger algebra, a recently introduced extension of the Bose-Mesner algebra, Schrijver formulated a new SDP strengthening of the LP approach. In this project we look at the dual solutions of the semidefinite programming bound for binary error-correcting codes. We explore the combinatorial meaning of these variables for small n and d, such as n = 4 and d = 2. To obtain information like this, we wrote a computer program with both Matlab and CVX modules to get solution of our primal SDP formulation. Our program efficiently generates the primal solutions with corresponding constraints for any n and d. We also wrote a program in C++ to parse the output of the primal SDP problem, and another Matlab script to generate the dual SDP problem, which could be used in assigning combinatorial meaning to the values given in the dual optimal solution. Our code not only computes both the primal and dual optimal variable values, but allows the researcher to display them in meaningful ways and to explore their relationship and dependence on arameters. These values are expected to be useful for later study of the combinatorial meaning of such solutions."
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Saeed, Mohamed Ahmed. "Approche algébrique sur l'équivalence de codes". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR034/document.
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Le problème d’´équivalence de code joue un rôle important dans la théorie de code et la cryptographie basée sur le code. Cela est dû à son importance dans la classification des codes ainsi que dans la construction et la cryptanalyse des cryptosystèmes à base de codes. Il est également lié à un problème ouvert d’isomorphisme de graphes, un problème bien connu dans le domaine de la théorie de la complexité. Nous prouvons pour les codes ayant un hull trivial qu’il existe une réduction polynomiale de l’équivalence par permutation de codes à l’isomorphisme de graphes. Cela montre que cette sous-classe d’équivalence de permutation n’est pas plus dure que l’isomorphisme de graphes. Nous introduisons une nouvelle méthode pour résoudre le problème d’équivalence de code. Nous développons des approches algébriques pour résoudre le problème dans ses deux versions : en permutation et en diagonale. Nous construisons un système algébrique en établissant des relations entre les matrices génératrices et les matrices de parité des codes équivalents. Nous nous retrouvons avecun système plusieurs variables d’équations linéaires et quadratiques qui peut être résolu en utilisant des outils algébriques tels que les bases de Groebner et les techniques associées. Il est possible en théorie de résoudre l’équivalence de code avec des techniques utilisant des bases de Groebner. Cependant, le calcul en pratique devient complexe à mesure que la longueur du code augmente. Nous avons introduit plusieurs améliorations telles que la linéarisation par bloc et l’action de Frobenius. En utilisant ces techniques, nous identifions de nombreux cas où le problème d’équivalence de permutation peut être résolu efficacement. Notre méthode d’équivalence diagonale résout efficacement le problème dans les corps de petites tailles, à savoir F3 et F4. L’augmentation de la taille du corps entraîne une augmentation du nombre de variables dans notre système algébrique, ce qui le rend difficile à résoudre. Nous nous intéressons enfin au problème d’isomorphisme de graphes en considérant un système algébrique quadratique pour l’isomorphisme de graphes. Pour des instances tirées aléatoirement, le système possède des propriétés intéressantes en termes de rang de la partie linéaire et du nombre de variables. Nousrésolvons efficacement le problème d’isomorphisme de graphes pour des graphes aléatoires avec un grand nombre de sommets, et également pour certains graphes réguliers tels que ceux de Petersen, Cubical et Wagner.123Code equivalence problem plays an important role in coding theory and code based cryptography.That is due to its significance in classification of codes and also construction and cryptanalysis of code based cryptosystems. It is also related to the long standing problem of graph isomorphism, a well-known problem in the world of complexity theory. We introduce new method for solving code equivalence problem. We develop algebraic approaches to solve the problem in its permutation and diagonal versions. We build algebraic system by establishing relations between generator matrices and parity check matrices of the equivalent codes. We end up with system of multivariables of linear and quadratic equations which can be solved using algebraic tools such as Groebner basis and related techniques. By using Groebner basis techniques we can solve the code equivalence but the computation becomes complex as the length of the code increases. We introduced several improvements such as block linearization and Frobenius action. Using these techniques we identify many cases where permutation equivalence problem can be solved efficiently. Our method for diagonal equivalence solves the problem efficiently in small fields, namely F3 and F4. The increase in the field size results in an increase in the number of variables in our algebraic system which makes it difficult to solve. We introduce a new reduction from permutation code equivalence when the hull is trivial to graph isomorphism. This shows that this subclass of permutation equivalence is not harder than graph isomorphism.Using this reduction we obtain an algebraic system for graph isomorphism with interesting properties in terms of the rank of the linear part and the number of variables. We solve the graph isomorphism problem efficiently for random graphs with large number of vertices and also for some regular graphs such as Petersen, Cubical and Wagner Graphs
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Lestringant, Pierre. "Identification d'algorithmes cryptographiques dans du code natif". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S067/document.
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Cette thèse traite de la conception de méthodes automatisées ou semi-automatisées pour détecter et identifier des algorithmes cryptographiques dans des programmes compilés en langage machine. La première méthode proposée a pour but l'identification de primitives symétriques. L'implémentation en langage machine d'une primitive symétrique, assimilée à une suite d'instructions, est représentée par un graphe. Sous cette forme, le code est modifié à l'aide de règles de réécriture tout en préservant une certaine notion de sémantique lors d'une phase dite de normalisation. L'objectif est de faire émerger des expressions communes à différentes implémentations d'une même primitive. Ces expressions servent alors de base à la création de signatures efficaces. La recherche de ces signatures s'effectue à l'aide d'un algorithme énumérant les isomorphismes de sous-graphe. La seconde méthode, conçue en complément de la première, produit une représentation synthétique facilitant l'identification des modes opératoires. Cette représentation se définit comme le plus petit sous-graphe préservant les distances entre des sous-ensembles de nœuds précédemment identifiés comme étant les paramètres d'entrée et de sortie des primitives impliquéesThis thesis is about the design of automatic or semi-automatic methods to detect and identify cryptographic algorithms inside programs compiled into machine code. Two methods are presented. The objective of the first method is to identify cryptographic primitives. A machine code implementation of a cryptographic primitive, regarded as a sequence of instructions, is represented by a graph structure. During a normalization phase, a set of rewrite rules is used to modify this graph representation while preserving a specific notion of semantics. The goal is to converge towards expressions which are shared across several implementations of the same primitive. We use these expressions as a basis to create efficient signatures. A subgraph isomorphism enumeration algorithm is used to search for signatures. The second method is built on top of the first one. It produces a synthetic representation designed to help in the identification of modes of operation. This synthetic representation is defined as the smallest subgraph which preserve distances between sets of vertices previously identified as the input and output parameters of the primitives involved within the mode of operation
Livros sobre o assunto "Graphe de code"
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Blahut, Richard E., e Ralf Koetter, eds. Codes, Graphs, and Systems. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0895-3.
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Foo, Simon. Convolutional codes on cayley graphs. Ottawa: National Library of Canada, 2002.
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3
Tonchev, Vladimir. Combinatorial configurations: Designs, codes, graphs. Harlow, Essex, England: Longman Scientific & Technical, 1988.
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4
Tonchev, Vladimir D. Combinatorial configurations: Designs, codes, graphs. Harlow: Longman Scientific & Technical, 1988.
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5
Lint, Jacobus Hendricus van, 1932-, ed. Designs, graphs, codes, and their links. Cambridge: Cambridge University Press, 1991.
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Morris, Anthony Robert. Self dual codes generated by graphs. Birmingham: University of Birmingham, 1994.
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Cameron, Peter J. Designs, graphs, codes and their links. Cambridge: C. U. P., 1991.
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1971-, Kim Saejoon, ed. Fundamentals of codes, graphs, and iterative decoding. Boston: Kluwer Academic Publishers, 2003.
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Cull, Paul. Perfect codes, NP-completeness, and towers of Hanoi graphs. Corvallis, OR: Oregon State University, Dept. of Computer Science, 1998.
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Cull, Paul. Perfect codes, NP-completeness, and towers of Hanoi graphs. Corvallis, OR: Oregon State University, Dept. of Computer Science, 1998.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Graphe de code"
1
Johnsson, Thomas. "Target code generation from G-machine code". In Graph Reduction, 119–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/3-540-18420-1_53.
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Mohan, Anshuman, Wei Xiang Leow e Aquinas Hobor. "Functional Correctness of C Implementations of Dijkstra’s, Kruskal’s, and Prim’s Algorithms". In Computer Aided Verification, 801–26. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-81688-9_37.
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AbstractWe develop machine-checked verifications of the full functional correctness of C implementations of the eponymous graph algorithms of Dijkstra, Kruskal, and Prim. We extend Wang et al.’s CertiGraph platform to reason about labels on edges, undirected graphs, and common spatial representations of edge-labeled graphs such as adjacency matrices and edge lists. We certify binary heaps, including Floyd’s bottom-up heap construction, heapsort, and increase/decrease priority.Our verifications uncover subtle overflows implicit in standard textbook code, including a nontrivial bound on edge weights necessary to execute Dijkstra’s algorithm; we show that the intuitive guess fails and provide a workable refinement. We observe that the common notion that Prim’s algorithm requires a connected graph is wrong: we verify that a standard textbook implementation of Prim’s algorithm can compute minimum spanning forests without finding components first. Our verification of Kruskal’s algorithm reasons about two graphs simultaneously: the undirected graph undergoing MSF construction, and the directed graph representing the forest inside union-find. Our binary heap verification exposes precise bounds for the heap to operate correctly, avoids a subtle overflow error, and shows how to recycle keys to avoid overflow.
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Reinders, James, Ben Ashbaugh, James Brodman, Michael Kinsner, John Pennycook e Xinmin Tian. "Where Code Executes". In Data Parallel C++, 25–59. Berkeley, CA: Apress, 2020. http://dx.doi.org/10.1007/978-1-4842-5574-2_2.
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Maitra, Deepankar. "Introduction to Graphs". In Beginner's Guide to Code Algorithms, 101–17. New York: CRC Press, 2021. http://dx.doi.org/10.1201/9781003214335-8.
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Ródenas-López, Manuel A., Pedro M. Jiménez-Vicario e Andrea Giordano. "Poetics of Code/Code of Poetics. Generative Design Applied to ‘Arte Concreta’ Masterpieces". In Graphic Imprints, 23–37. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93749-6_3.
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Shokrollahi, M. Amin. "Codes and Graphs". In STACS 2000, 1–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/3-540-46541-3_1.
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Brouwer, Andries E., Arjeh M. Cohen e Arnold Neumaier. "Graphs Related to Codes". In Distance-Regular Graphs, 345–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74341-2_11.
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Karrenberg, Ralf. "Dynamic Code Variants". In Automatic SIMD Vectorization of SSA-based Control Flow Graphs, 127–39. Wiesbaden: Springer Fachmedien Wiesbaden, 2015. http://dx.doi.org/10.1007/978-3-658-10113-8_7.
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Djordjevic, Ivan, William Ryan e Bane Vasic. "Graph-Based Codes". In Coding for Optical Channels, 179–206. Boston, MA: Springer US, 2010. http://dx.doi.org/10.1007/978-1-4419-5569-2_5.
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Fay, Colin, Sébastien Rochette, Vincent Guyader e Cervan Girard. "Optimizing {shiny} Code". In Engineering Production-Grade Shiny Apps, 267–88. Boca Raton: Chapman and Hall/CRC, 2021. http://dx.doi.org/10.1201/9781003029878-23.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Graphe de code"
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Nikolentzos, Giannis, Polykarpos Meladianos, Stratis Limnios e Michalis Vazirgiannis. "A Degeneracy Framework for Graph Similarity". In Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. California: International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/360.
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The problem of accurately measuring the similarity between graphs is at the core of many applications in a variety of disciplines. Most existing methods for graph similarity focus either on local or on global properties of graphs. However, even if graphs seem very similar from a local or a global perspective, they may exhibit different structure at different scales. In this paper, we present a general framework for graph similarity which takes into account structure at multiple different scales. The proposed framework capitalizes on the well-known k-core decomposition of graphs in order to build a hierarchy of nested subgraphs. We apply the framework to derive variants of four graph kernels, namely graphlet kernel, shortest-path kernel, Weisfeiler-Lehman subtree kernel, and pyramid match graph kernel. The framework is not limited to graph kernels, but can be applied to any graph comparison algorithm. The proposed framework is evaluated on several benchmark datasets for graph classification. In most cases, the core-based kernels achieve significant improvements in terms of classification accuracy over the base kernels, while their time complexity remains very attractive.
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Hsu, Cheng-Ho, e Kin-Tak Lam. "A Method for the Identification of Displacement Isomorphism of Planetary Gear Trains". In ASME 1992 Design Technical Conferences. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/detc1992-0419.
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Abstract The purpose of this paper is to present an efficient method for the identification of the displacement isomorphism of planetary gear trains. For every planetary gear train, the kinematic structure is characterized by its displacement graph and rotation graph. A mathematical representation, called the Structural Code, is introduced to represent the topological structure of the displacement graph and rotation graph of a planetary gear train. Based on the Structural Codes of displacement graphs and rotation graphs, the linear and rotational displacement isomorphism of planetary gear trains can be identified in an unambiguous way. Finally, an interactive computer program is developed for the automatic identification of the displacement isomorphism of planetary gear trains.
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Schatz, Y., e B. Domer. "Optimizing IFC-structured Data Graph for Code Compliance Checking". In The 29th EG-ICE International Workshop on Intelligent Computing in Engineering. EG-ICE, 2022. http://dx.doi.org/10.7146/aul.455.c208.
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Construction code compliance checking requires applying specific computerinterpretable rules on datasets. A proposed solution is to represent IFC data as an RDF graph and perform rule-checking using a rule engine. However, the generated graph has a complicated structure since it follows the IFC data model. Consequently, the definition of compliance rules can be challenging, and rules are sensitive to variations of input graphs structure. A methodology is proposed to optimize graphs by giving them a predefined or "standardized" structure. A case study shows that optimization allows the formulation of more straightforward and easier-to-write compliance rules, applicable to all standardized graphs regardless of the initially used BIM authoring tool. In addition, graph size is significantly reduced.
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Zhou, Kaixiong, Qingquan Song, Xiao Huang, Daochen Zha, Na Zou e Xia Hu. "Multi-Channel Graph Neural Networks". In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/188.
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The classification of graph-structured data has be-come increasingly crucial in many disciplines. It has been observed that the implicit or explicit hierarchical community structures preserved in real-world graphs could be useful for downstream classification applications. A straightforward way to leverage the hierarchical structure is to make use the pooling algorithms to cluster nodes into fixed groups, and shrink the input graph layer by layer to learn the pooled graphs.However, the pool shrinking discards the graph details to make it hard to distinguish two non-isomorphic graphs, and the fixed clustering ignores the inherent multiple characteristics of nodes. To compensate the shrinking loss and learn the various nodes’ characteristics, we propose the multi-channel graph neural networks (MuchGNN). Motivated by the underlying mechanisms developed in convolutional neural networks, we define the tailored graph convolutions to learn a series of graph channels at each layer, and shrink the graphs hierarchically to en-code the pooled structures. Experimental results on real-world datasets demonstrate the superiority of MuchGNN over the state-of-the-art methods.
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Gupta, Rajeev, Madhusudhanan Krishnamoorthy e Vipindeep Vangala. "Better Graph Embeddings for Enterprise Graphs". In CODS-COMAD 2024: 7th Joint International Conference on Data Science & Management of Data (11th ACM IKDD CODS and 29th COMAD). New York, NY, USA: ACM, 2024. http://dx.doi.org/10.1145/3632410.3632412.
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Kataoka, Tetsuya, e Akihiro Inokuchi. "Hadamard Code Graph Kernels for Classifying Graphs". In International Conference on Pattern Recognition Applications and Methods. SCITEPRESS - Science and and Technology Publications, 2016. http://dx.doi.org/10.5220/0005634700240032.
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El-Gayyar, M. S., H. M. El-Eashy e M. Zaki. "Structural Synthesis and Enumeration of Epicyclic Gear Mechanisms Up to 12-Links Using Acyclic Graph Method". In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91136.
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In this paper, a new approach for graphical enumeration of epicyclic gear mechanisms is presented using the concept of acyclic graph. A new graphical code has been introduced to specify the priorities of all vertices of associated displacement graph. This graphical code is used to identify open graph, redundant links and isomorphic graphs. A computer program has been developed for automatic enumeration of displacement graphs as well as automatic detection of isomorphic graphs and open graphs and graphs with a redundant link without using adjacency matrices. This simplified methodology has been applied for the enumeration of epicyclic gear mechanisms with up to 12-links having up to 9 coaxial links. An atlas for 11 and 12-link mechanisms has been constructed using the proposed methodology.
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Jongsma, T. J., e W. Zhang. "An Efficient Algorithm for Finding Optimum Code Under the Condition of Incident Degree". In ASME 1992 Design Technical Conferences. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/detc1992-0409.
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Abstract This paper deals with the identification of kinematic chains. A kinematic chain can be represented by a weighed graph. The identification of kinematic chains is thereby transformed into the isomorphism problem of graph. When a computer program has to detect isomorphism between two graphs, the first step is to set up the corresponding connectivity matrices for each graph, which are adjacency matrices when considering adjacent vertices and the weighed edges between them. Because these adjacency matrices are dependent of the initial labelling, one can not conclude that the graphs differ when these matrices differ. The isomorphism problem needs an algorithm which is independent of the initial labelling. This paper provides such an algorithm.
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Zhang, Yangkang, Chenye Meng, Zejian Li, Pei Chen, Guang Yang, Changyuan Yang e Lingyun Sun. "Learning Object Consistency and Interaction in Image Generation from Scene Graphs". In Thirty-Second International Joint Conference on Artificial Intelligence {IJCAI-23}. California: International Joint Conferences on Artificial Intelligence Organization, 2023. http://dx.doi.org/10.24963/ijcai.2023/192.
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This paper is concerned with synthesizing images conditioned on a scene graph (SG), a set of object nodes and their edges of interactive relations. We divide existing works into image-oriented and code-oriented methods. In our analysis, the image-oriented methods do not consider object interaction in spatial hidden feature. On the other hand, in empirical study, the code-oriented methods lose object consistency as their generated images miss certain objects in the input scene graph. To alleviate these two issues, we propose Learning Object Consistency and Interaction (LOCI). To preserve object consistency, we design a consistency module with a weighted augmentation strategy for objects easy to be ignored and a matching loss between scene graphs and image codes. To learn object interaction, we design an interaction module consisting of three kinds of message propagation between the input scene graph and the learned image code. Experiments on COCO-stuff and Visual Genome datasets show our proposed method alleviates the ignorance of objects and outperforms the state-of-the-art on visual fidelity of generated images and objects.
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Zhu, Hua, Hong Huang, Kehan Yin, Zejun Fan, Hai Jin e Bang Liu. "CausalNET: Unveiling Causal Structures on Event Sequences by Topology-Informed Causal Attention". In Thirty-Third International Joint Conference on Artificial Intelligence {IJCAI-24}. California: International Joint Conferences on Artificial Intelligence Organization, 2024. http://dx.doi.org/10.24963/ijcai.2024/790.
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Causal discovery on event sequences holds a pivotal significance across domains such as healthcare, finance, and industrial systems. The crux of this endeavor lies in unraveling causal structures among event types, typically portrayed as directed acyclic graphs (DAGs). Nonetheless, prevailing methodologies often grapple with untenable assumptions and intricate optimization hurdles. To address these challenges, we present a novel model named CausalNET. At the heart of CausalNET is a special prediction module based on the Transformer architecture, which prognosticates forthcoming events by leveraging historical occurrences, with its predictive prowess amplified by a trainable causal graph engineered to fathom causal relationships among event types. Further, to augment the predictive paradigm, we devise a causal decay matrix to encapsulate the reciprocal influence of events upon each other within the topological network. During training, we alternatively refine the prediction module and fine-tune the causal graph. Comprehensive evaluation on a spectrum of real-world and synthetic datasets underscores the superior performance and scalability of CausalNET, which marks a promising step forward in the realm of causal discovery. Code and Appendix are available at https://github.com/CGCL-codes/CausalNET.
Relatórios de organizações sobre o assunto "Graphe de code"
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Wang, Yanli, Sam Sham e Mark C. Messner. Report on FY19 Testing in Support of Grade 91 Core Block Code Case. Office of Scientific and Technical Information (OSTI), setembro de 2019. http://dx.doi.org/10.2172/1569371.
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Shashkov, Mikhail Jurievich, e Konstantin Lipnikov. Dependency graph for code analysis on emerging architectures. Office of Scientific and Technical Information (OSTI), agosto de 2017. http://dx.doi.org/10.2172/1374308.
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Boutin, Debra, e Victoria Horan. Identifying Codes on Directed De Bruijn Graphs. Fort Belvoir, VA: Defense Technical Information Center, dezembro de 2014. http://dx.doi.org/10.21236/ada623527.
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Tripakis, Stavros, Dai Bui, Bert Rodiers e Edward A. Lee. Compositionality in Synchronous Data Flow: Modular Code Generation from Hierarchical SDF Graphs. Fort Belvoir, VA: Defense Technical Information Center, outubro de 2009. http://dx.doi.org/10.21236/ada538756.
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Zhai, Liangliang, e Xuanlong Ma. Perfect Codes in Proper Order Divisor Graphs of Finite Groups. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, dezembro de 2020. http://dx.doi.org/10.7546/crabs.2020.12.04.
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Rickard, N. D. STRUCTURAL DESIGN CRITERIA FOR REPLACEABLE GRAPHITE CORE ELEMENTS. Office of Scientific and Technical Information (OSTI), setembro de 1989. http://dx.doi.org/10.2172/10197186.
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Kang, Grace, Sifat Muin, Jorge Archbold, Bitanoosh Woods e Khalid Mosalam. Expected Earthquake Performance of Buildings Designed to the California Building Code. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, julho de 2019. http://dx.doi.org/10.55461/lotg8562.
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The brochure explains the intent of the California Building Code, the expected performance of code-compliant new buildings when they are subjected to moderate and large earthquakes, possible consequences to residents, businesses, and communities, and initial proactive actions that can be taken. “This publication combines information from the earthquake engineering community as well as policy and community officials, and it incorporates input from SSC’s commissioners and staff, whose valuable feedback reflected their diverse range of expertise and experience,” said Grace Kang, PEER Director of Communications. “The brochure is an educational tool intended to raise public awareness and provide basic information for decision-makers. It can be used to initiate and catalyze discussion.”
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Robert L. Bratton e Tim D. Burchell. Status of ASME Section III Task Group on Graphite Support Core Structures. Office of Scientific and Technical Information (OSTI), agosto de 2005. http://dx.doi.org/10.2172/911242.
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Duffy, Stephen. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components. Office of Scientific and Technical Information (OSTI), setembro de 2013. http://dx.doi.org/10.2172/1095244.
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BOGER, R. M. Test Plan for Rotary Mode Core Sample Truck Grapple Hoist Level Wind System. Office of Scientific and Technical Information (OSTI), agosto de 1999. http://dx.doi.org/10.2172/797723.
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