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排序方式: 共有445条查询结果,搜索用时 15 毫秒
91.
Software and Systems Modeling - The Discrete Event System Specification (DEVS) is a modular and hierarchical Modeling and Simulation (M&S) formalism based on systems theory that provides a... 相似文献
92.
Carlos Alberto Fraga Pimentel Filho Benjamin Bustos Arnaldo de Albuquerque Araújo Silvio Jamil Ferzoli Guimarães 《Multimedia Tools and Applications》2017,76(21):22019-22042
Sketch-based image retrieval (SBIR) lets one express a precise visual query with simple and widespread means. In the SBIR approaches, the challenge consists in representing the image dataset features in a structure that allows one to efficiently and effectively retrieve images in a scalable system. We put forward a sketch-based image retrieval solution where sketches and natural image contours are represented and compared, in both, the compressed-domain of wavelet and in the pixel domain. The query is efficiently performed in the wavelet domain, while effectiveness refinements are achieved using the pixel domain to verify the spatial consistency between the sketch strokes and the natural image contours. Also, we present an efficient scheme of inverted lists for sketch-based image retrieval using the compressed-domain of wavelets. Our proposal of indexing presents two main advantages, the amount of the data to compute the query is smaller than the traditional method while it presents a better effectiveness. 相似文献
93.
Detecting objects in complex scenes while recovering the scene layout is a critical functionality in many vision-based applications. In this work, we advocate the importance of geometric contextual reasoning for object recognition. We start from the intuition that objects' location and pose in the 3D space are not arbitrarily distributed but rather constrained by the fact that objects must lie on one or multiple supporting surfaces. We model such supporting surfaces by means of hidden parameters (i.e. not explicitly observed) and formulate the problem of joint scene reconstruction and object recognition as the one of finding the set of parameters that maximizes the joint probability of having a number of detected objects on K supporting planes given the observations. As a key ingredient for solving this optimization problem, we have demonstrated a novel relationship between object location and pose in the image, and the scene layout parameters (i.e. normal of one or more supporting planes in 3D and camera pose, location and focal length). Using a novel probabilistic formulation and the above relationship our method has the unique ability to jointly: i) reduce false alarm and false negative object detection rate; ii) recover object location and supporting planes within the 3D camera reference system; iii) infer camera parameters (view point and the focal length) from just one single uncalibrated image. Quantitative and qualitative experimental evaluation on two datasets (desk-top dataset [1] and LabelMe [2]) demonstrates our theoretical claims. 相似文献
94.
Silvio A. Araujo Ademir A. Constantino Kelly C. Poldi 《International Transactions in Operational Research》2011,18(1):115-127
This paper deals with the one‐dimensional integer cutting stock problem, which consists of cutting a set of available objects in stock in order to produce ordered smaller items in such a way as to minimize the waste of material. The case in which there are various types of objects available in stock in limited quantities is studied. A new heuristic method based on the evolutionary algorithm concept is proposed to solve the problem. This heuristic is empirically analyzed by solving randomly generated instances and the results are compared with other methods from the literature. 相似文献
95.
Yguaratã Cerqueira Cavalcanti Paulo Anselmo da Mota Silveira Neto Daniel Lucrédio Tassio Vale Eduardo Santana de Almeida Silvio Romero de Lemos Meira 《Software Quality Journal》2013,21(1):39-66
Duplicate bug report entries in bug trackers have a negative impact on software maintenance and evolution. This is due, among other factors, to the increased time spent on report analysis and validation, which in some cases takes over 20 min. Therefore, a considerable amount of time is lost in duplicate bug report analysis. In order to understand the possible factors that cause bug report duplication and its impact on software development, this paper presents an exploratory study in which bug tracking data from private and open source projects were analyzed. The results show, for example, that all projects we investigated had duplicate bug reports and a considerable amount of time was wasted by this duplication. Furthermore, features such as project lifetime, staff size, and the number of bug reports do not seem to be significant factors for duplication, while others, such as the submitters’ profile and the number of submitters, do seem to influence the bug report duplication. 相似文献
96.
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98.
Josè M. Prieto Patrizia Iacopini Pierluigi Cioni Silvio Chericoni 《Food chemistry》2007,104(3):889-895
The essential oil obtained from aerial parts of Satureja montana L. and Origanum vulgare L. (Labiatae) along with four of its main components, p-cymene, carvacrol, thymol and γ-terpinene were tested in models of in vitro peroxynitrite-induced formation of both 3-nitrotyrosine and malondialdehyde, two biomarkers of the oxidative stress of recognised pathological and toxicological significance. The essential oils showed a significant activity, thus decreasing 3-nitrotyrosine formation (IC50 values of 43.9 μg/ml for S. montana and 19.2 μg/ml for O. vulgare), and also inhibited the peroxynitrite induced malondialdehyde formation (IC50 values of 27.2 μg/ml and 17.0 μg/ml respectively). Thymol and carvacrol inhibited 3-nitrotyrosine formation (IC50 values of 81.3 μM and 106.3 μM; ascorbic acid IC50 = 400 μM) and reduced malondialdehyde formation (IC50 values of 43.9 μM and 70.1 μM respectively; trolox IC50 = 240 μM). On the contrary, p-cymene and γ-terpinene were completely inactive in both assays under the concentration of 300 μg/ml. These results support, in particular for origanum, the nutraceutical value of these spices and the potential of thymol and carvacrol in preventing the formation of toxic products by the action of reactive nitrogen species. 相似文献
99.
Silvio Ghilardi Enrica Nicolini Silvio Ranise Daniele Zucchelli 《Annals of Mathematics and Artificial Intelligence》2007,50(3-4):231-254
The theory of arrays, introduced by McCarthy in his seminal paper “Towards a mathematical science of computation,” is central
to Computer Science. Unfortunately, the theory alone is not sufficient for many important verification applications such as
program analysis. Motivated by this observation, we study extensions of the theory of arrays whose satisfiability problem
(i.e., checking the satisfiability of conjunctions of ground literals) is decidable. In particular, we consider extensions
where the indexes of arrays have the algebraic structure of Presburger arithmetic and the theory of arrays is augmented with
axioms characterizing additional symbols such as dimension, sortedness, or the domain of definition of arrays. We provide
methods for integrating available decision procedures for the theory of arrays and Presburger arithmetic with automatic instantiation
strategies which allow us to reduce the satisfiability problem for the extension of the theory of arrays to that of the theories
decided by the available procedures. Our approach aims to re-use as much as possible existing techniques so as to ease the
implementation of the proposed methods. To this end, we show how to use model-theoretic, rewriting-based theorem proving (i.e.,
superposition), and techniques developed in the Satisfiability Modulo Theories communities to implement the decision procedures
for the various extensions.
相似文献
100.
Silvio Barbarelli Gaetano Florio Mario Amelio Nino Michele Scomaienchi Antonino Cutrupi ManuelSanchez Blanco Giacomo Lo Zupone 《能源与动力工程:英文版》2014,(3):476-486
Tidal currents are a resource of great potentiality and not yet fully explored. Several efforts have been made to exploit these resources, but the costs associated to the deployment of tidal plants in marine environments are usually too high. The aim of this work is to present a system able to handle with the above mentioned problems, through the development of a particular hydrokinetic turbine design. In previous works, the authors described a basic turbine configuration achieving interesting performances, although some operational inconveniences were detected. Those problems have been existing so the solution should be optimized and redesigned. As a result, a new design of the turbine is proposed, consisting of a double rotor spinning in opposite directions in order to balance the induced mechanical torque. From preliminary evaluations related to the Messina Strait tidal cycles (Punta Pezzo site, RC, Italy), a single 12 m diameter turbine can supply a power of about 500 kW with a peak current speed of 3 m/s and deliver up to 450 MWh/year. 相似文献