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1.
Complete Mining of Frequent Patterns from Graphs: Mining Graph Data   总被引:16,自引:0,他引:16  
Basket Analysis, which is a standard method for data mining, derives frequent itemsets from database. However, its mining ability is limited to transaction data consisting of items. In reality, there are many applications where data are described in a more structural way, e.g. chemical compounds and Web browsing history. There are a few approaches that can discover characteristic patterns from graph-structured data in the field of machine learning. However, almost all of them are not suitable for such applications that require a complete search for all frequent subgraph patterns in the data. In this paper, we propose a novel principle and its algorithm that derive the characteristic patterns which frequently appear in graph-structured data. Our algorithm can derive all frequent induced subgraphs from both directed and undirected graph structured data having loops (including self-loops) with labeled or unlabeled nodes and links. Its performance is evaluated through the applications to Web browsing pattern analysis and chemical carcinogenesis analysis.  相似文献   
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A reduction of depth variation in a shallow trench isolation process is desired for obtaining more stable electrical performances of silicon devices. By applying an optimized run-to-run control system to a silicon trench etching process, trench depth variation of the process was reduced. Cp/Cpk of the trench depth of product wafers were improved from 1.10/0.83 to 1.39/1.34 by the control.  相似文献   
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Recordings were made from neurons in intact pre- and paravertebral guinea-pig sympathetic ganglia using intracellular microelectrodes. Fast excitatory synaptic responses were evoked by stimulation of preganglionic and peripheral nerve trunks. Suramin (0.1-1 mM) did not affect passive or active membrane properties, nor the amplitude or decay time-course of either synaptic potentials or synaptic currents. Synaptic responses were reversibly reduced in amplitude by hexamethonium (98.7 +/- 0.8%, 50-1000 microM) and d-tubocurarine (95.3 +/- 2.6%, 10-280 microM). ATP (0.5-1 mM) and alpha,beta-methylene ATP (1-40 microM) applied in the bathing solution produced no significant changes in resting membrane potential or input resistance. Prolonged application (up to 25 min) of either compound was also without effect on synaptic responses. These substances also did not affect ganglion cells axotomized one to five days in vivo. These data suggest that activation of P2X-purinoceptors is not involved in the generation of fast excitatory synaptic responses in intact guinea-pig sympathetic ganglia. It appears that dissociation of these neurons must markedly increase their sensitivity to purine nucleotides.  相似文献   
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We have studied the effect of shear stress on thin films of Pt(dpg)2 and chromic compounds, spiropyrans, by using the sapphire-anvil cell. From Raman spectra under hydrostatic pressure and shear deformation, the shear stress effect on Pt(dpg)2 was quantitatively estimated. Then, it was observed that the color of spiropyran (1′,3′-dihydro- 1′,3′,3′-trimethyl-6-nitro-spiro [2H-1-benzopyran-2,2′-[2H]indole]) was changed by shear stress.  相似文献   
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When polycyclic aromatic hydrocarbons are heattreated with an excess amount of sulfur in evacuated closed tubing, they react with sulfur, liberating hydrogen sulfide; after removing unreacted sulfur, dark-colored compounds in the form of an amorphous solid are obtained. These compounds possess semiconductive properties; the electrical resistivity is greatly reduced from that of the original hydrocarbons. The ESR absorption of these compounds is characterized by the large g-value, which is due to sulfur-centered unpaired electrons.From these findings, with the results of chemical analysis, we can assume that the polycyclic aromatic nuclei crosslink with each other through the sulfur-bridges, which are good electron transport paths, and yield the aromaticity of the molecule. The sulfur-bridged polycyclic aromatic hydrocarbons can be considered as the structural model of chars and cokes. The ESR studies of a violanthrene-sulfur compound were carried out during its heat-treatment up to 1000°C.  相似文献   
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Elimination of the data processing bottleneck in high-throughput sequencing will require both improved accuracy of data processing software and reliable measures of that accuracy. We have developed and implemented in our base-calling program phred the ability to estimate a probability of error for each base-call, as a function of certain parameters computed from the trace data. These error probabilities are shown here to be valid (correspond to actual error rates) and to have high power to discriminate correct base-calls from incorrect ones, for read data collected under several different chemistries and electrophoretic conditions. They play a critical role in our assembly program phrap and our finishing program consed.  相似文献   
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