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Li H.,Graduate University of China Academy of Science | Li H.,CAS Institute of Engineering Thermophysics | Yang K.,CAS Institute of Engineering Thermophysics | Xu J.,CAS Institute of Engineering Thermophysics
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2010

Three-dimensional numerical simulations of wall effect were performed for an S809 airfoil model mounted in a wind tunnel. Two turbulent models, Spalart-Allmaras and k-ε(Shear-Stress Transport), were used in the simulations. The results show that simulation agree well with the experimental data. It also turns out that the effect of wall boundary layer on the flow pattern over the airfoil model surface is significant and the strong three-dimensionality wall effect is introduced when the angles of attack of flow are relatively large.

Xu M.,China Agricultural University | Li P.,Graduate University of China Academy of Science | Xie F.,Agricultural University of Hebei | Huang D.,China Agricultural University | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

In order to assess variability of soil organic carbon(SOC) across different land-use types and management practices in agro-pastoral zone, two land-use types, permanent grassland and reclaimed cropland in Guyuan County, Hebei province of Northern China, were investigated with SOC density in 0-10, 10-20, 20-30, 30-40, 40-50 cm soil layers and correlations of SOC density with soil bulk density and SOC content as affected by land-use types and management practices change. The results showed that the carbon stored in soils for different land-use types and management practices ranged from 8.21-11.30 kg/m2. The SOC all declined at each successive increment from 0-50 cm depth across the five land-use types and management practices, with the relative distribution greatly skewed towards the top layers. SOC in 0-50 cm soil layers of permanent grassland under different management practices were higher than those in disturbed soils of reclaimed cropland (RC) and fallowing (FC). For permanent grassland, the management practice of GM has the the highest SOC density in 0-50 cm soil layer, the least SOC density was displayed by FG. For reclaimed grassland, after about 10 years FC, SOC were higher signifcantly in the 0-50 cm soil layer comparing to RC. The results also indicated that land-use types and mangement practices had significantly effect on soil bulk density and SOC content, then on SOC density. GM or grassland enclosure and under controlled grazing therefore was the most feasible and benign short-term grassland management option which could deposit even higher carbon dioxide in agro-pastoral ecotone, Northern China.

Peng P.,CAS Institute of Software | Peng P.,Graduate University of China Academy of Science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

We give a local algorithm to extract dense bipartite-like subgraphs which characterize cyber-communities in the Web [13]. We use the bipartiteness ratio of a set as the quality measure that was introduced by Trevisan [20]. Our algorithm, denoted as FindDenseBipartite (v,s,θ), takes as input a starting vertex v, a volume target s and a bipartiteness ratio parameter θ and outputs an induced subgraph of G. It is guaranteed to have the following approximation performance: for any subgraph S with bipartiteness ratio θ, there exists a subset S θ ⊆ S such that vol(S θ) ≥ vol(S)/9 and that if the starting vertex v ∈ S θ and s ≥ vol(S), the algorithm FindDenseBipartite (v,s,θ) outputs a subgraph (X,Y) with bipartiteness ratio O(√θ). The running time of the algorithm is O(s 2(Δ + logs)), where Δ is the maximum degree of G, independent of the size of G. © 2012 Springer-Verlag.

Long T.,Graduate University of China Academy of Science | Zhang W.,CAS Institute of Software
Proceedings - Asia-Pacific Software Engineering Conference, APSEC | Year: 2012

Different rules for proving properties have been studied for systems with different kinds of fairness constraints, such as justice, compassion and strengthened compassion. This work considers a kind of bounded fairness and propose a general form that includes these fairness constraints. The general form is referred to as mixed-fairness (m-fairness for short). A deductive rule for proving live ness properties under m-fairness is presented with examples illustrating the application of the deductive rule. © 2012 IEEE.

Peng P.,CAS Institute of Software | Peng P.,Graduate University of China Academy of Science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

We survey a recent new line of research on the small community phenomenon in networks, which characterizes the intuition and observation that in a broad class of networks, a significant fraction of nodes belong to some small communities. We propose the formal definition of this phenomenon as well as the definition of communities, based on which we are able to both study the community structure of network models, i.e., whether a model exhibits the small community phenomenon or not, and design new models that embrace this phenomenon in a natural way while preserving some other typical network properties such as the small diameter and the power law degree distribution. We also introduce the corresponding community detection algorithms, which not only are used to identify true communities and confirm the existence of the small community phenomenon in real networks but also have found other applications, e.g., the classification of networks and core extraction of networks. © 2012 Springer-Verlag.

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