838 research outputs found
Grid multi-wing butterfly chaotic attractors generated from a new 3-D quadratic autonomous system
Due to the dynamic characteristics of the Lorenz system, multi-wing chaotic systems are still confined in the positive half-space and fail to break the threshold limit. In this paper, a new approach for generating complex grid multi-wing attractors that can break the threshold limit via a novel nonlinear modulating function is proposed from the firstly proposed double-wing chaotic system. The proposed method is different from that of classical multi-scroll chaotic attractors generated by odd-symmetric multi-segment linear functions from Chua system. The new system is autonomous and can generate various grid multi-wing butterfly chaotic attractors without requiring any external forcing, it also can produce grid multi-wing both on the xz-plane and yz-plane. Basic properties of the new system such as dissipation property, equilibrium, stability, the Lyapunov exponent spectrum and bifurcation diagram are introduced by numerical simulation, theoretical analysis and circuit experiment, which confirm that the multi-wing attractors chaotic system has more rich and complicated chaotic dynamics. Finally, a novel module-based unified circuit is designed which provides some principles and guidelines for future circuitry design and engineering application. The circuit experimental results are consistent with the numerical simulation results. 
Towards Ontology-Based Program Analysis
Program analysis is fundamental for program optimizations, debugging,
and many other tasks. But developing program analyses has been a
challenging and error-prone process for general users. Declarative
program analysis has shown the promise to dramatically improve the
productivity in the development of program analyses. Current
declarative program analysis is however subject to some major
limitations in supporting cooperations among analysis tools, guiding
program optimizations, and often requires much effort for repeated
program preprocessing.
In this work, we advocate the integration of ontology into declarative
program analysis. As a way to standardize the definitions of concepts
in a domain and the representation of the knowledge in the domain,
ontology offers a promising way to address the limitations of current
declarative program analysis. We develop a prototype framework named
PATO for conducting program analysis upon ontology-based program
representation. Experiments on six program analyses confirm the
potential of ontology for complementing existing declarative program
analysis. It supports multiple analyses without separate program
preprocessing, promotes cooperative Liveness analysis between two
compilers, and effectively guides a data placement optimization for
Graphic Processing Units (GPU)
2,2′-(1,3,5,7-TetraÂoxo-1,2,3,5,6,7-hexaÂhydroÂpyrrolo[3,4-f]isoindole-2,6-diÂyl)diacetic acid N,N-dimethylÂformamide disolvate
The asymmetric unit of the title compound, C14H8N2O8·2C3H7NO or L·2DMF (DMF = N,N-dimethylÂformamide), contains one half of the centrosymmetric molÂecule L and one solvent molÂecule, which is disordered between two orientations in a 0.555 (4):0.445 (4) ratio. InterÂmolecular O—H⋯O hydrogen bonds link one L and two DMF molÂecules into a centrosymmetric hydrogen-bonded cluster. The crystal packing is further stabilized by weak interÂmolecular C—H⋯O hydrogen bonds
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