The key problem in unstructured P2P system is how to control "Flood".Some studies focus on constructing more efficient topology while others focus on better query algorithms.This paper presents HICUS(Hierarc...The key problem in unstructured P2P system is how to control "Flood".Some studies focus on constructing more efficient topology while others focus on better query algorithms.This paper presents HICUS(Hierarchical Interest-driven Community-based Unstructured System) motivated by a basic thought-whether the resources correlate with topology distinguishes structured and unstruc-tured P2P essentially.By introducing hierarchical "interest",HICUS organizes a quasi-structured topology through a pure distributed way,and provides a new platform for query algorithms.We study the procedure and performance of topology organization,and the simulations show that HICUS forms a small-world which can significantly improve the routing efficiency.展开更多
A quasicrystal has a structure intermediate between crystals and compound glasses. The disorder in glass makes its diffraction diffuse, so it is surprising that quasicrystals diffract more sharply than crystals. The g...A quasicrystal has a structure intermediate between crystals and compound glasses. The disorder in glass makes its diffraction diffuse, so it is surprising that quasicrystals diffract more sharply than crystals. The greater sharpness is computed to be due to the hierarchic structure with unit cell alignment in 3-dimensional space. Electron microscope phase contrast images map the comparatively heavy Mn atoms in icosahedral Al<sub>6</sub>Mn, where the transition metal locates the centers of unit cells inside clusters and superclusters. Because the solid is aperiodic, each diffracted beam is a product of multiple interplanar spacings combined, and this contrasts with the unique relationship between spacing and incident angle in Bragg diffraction from crystals. Simulated quasi-structure factors add the relative phase shifts that are in geometric series from cell to cluster to superclusters of increasing order. The scattering becomes coherent in best fit, angular configuration between the aperiodic solid and a longitudinally periodic X-ray or electron probe. The quasi-structure factors express angular divergence in each diffracted beam from its corresponding Bragg condition, and the divergence provides a special metric, essential for atomic measurement in the geometric solids. The fit is reinforced at all levels from the unit cell to cluster to high order superclusters. The optics operates under a new quasi-Bragg law in a new geometric space. In this paper, we proceed to examine the effect of specimen size on line resolution in diffraction, first analytically and secondly in simulation. The line resolution follows a power law on the supercluster order, matching its atomic population.展开更多
基金Supported by the National Natural Science Foundation of China (No.60602018 and 60772033)
文摘The key problem in unstructured P2P system is how to control "Flood".Some studies focus on constructing more efficient topology while others focus on better query algorithms.This paper presents HICUS(Hierarchical Interest-driven Community-based Unstructured System) motivated by a basic thought-whether the resources correlate with topology distinguishes structured and unstruc-tured P2P essentially.By introducing hierarchical "interest",HICUS organizes a quasi-structured topology through a pure distributed way,and provides a new platform for query algorithms.We study the procedure and performance of topology organization,and the simulations show that HICUS forms a small-world which can significantly improve the routing efficiency.
文摘A quasicrystal has a structure intermediate between crystals and compound glasses. The disorder in glass makes its diffraction diffuse, so it is surprising that quasicrystals diffract more sharply than crystals. The greater sharpness is computed to be due to the hierarchic structure with unit cell alignment in 3-dimensional space. Electron microscope phase contrast images map the comparatively heavy Mn atoms in icosahedral Al<sub>6</sub>Mn, where the transition metal locates the centers of unit cells inside clusters and superclusters. Because the solid is aperiodic, each diffracted beam is a product of multiple interplanar spacings combined, and this contrasts with the unique relationship between spacing and incident angle in Bragg diffraction from crystals. Simulated quasi-structure factors add the relative phase shifts that are in geometric series from cell to cluster to superclusters of increasing order. The scattering becomes coherent in best fit, angular configuration between the aperiodic solid and a longitudinally periodic X-ray or electron probe. The quasi-structure factors express angular divergence in each diffracted beam from its corresponding Bragg condition, and the divergence provides a special metric, essential for atomic measurement in the geometric solids. The fit is reinforced at all levels from the unit cell to cluster to high order superclusters. The optics operates under a new quasi-Bragg law in a new geometric space. In this paper, we proceed to examine the effect of specimen size on line resolution in diffraction, first analytically and secondly in simulation. The line resolution follows a power law on the supercluster order, matching its atomic population.
