Recently much attention has been paid to semantic overlay networks for information retrieval in large scale peer-to-peer networks,and much research work on semantic overlay protocols and searching algorithms has been ...
详细信息
Recently much attention has been paid to semantic overlay networks for information retrieval in large scale peer-to-peer networks,and much research work on semantic overlay protocols and searching algorithms has been done and the results indicate that semantic overlay is efficient for content searching in peer-to-peer ***,very limited work has been done to analyze and evaluate the characteristics of semantic overlay *** this paper we identify a natural property of semantic overlay networks,the community *** propose a mathematical model to evaluate the property of community structure of semantic P2P overlay networks.A heuristic algorithm is designed to optimize the community *** the evaluation model we compare the SemreX semantic overlay with the Gnutella *** demonstrate that a SemreX overlay network has the distinctive community structure feature,while a Gnutella-like network does *** also simulate a simple flooding protocol in both overlays to show that the overlay with community structure is more efficient for content searching.
Desktop virtualization is a very hot concept in both industry and academic communities. Since virtualized desktop system is based on multiple virtual machines (VM), it is necessary to design a distributed storage syst...
详细信息
Desktop virtualization is a very hot concept in both industry and academic communities. Since virtualized desktop system is based on multiple virtual machines (VM), it is necessary to design a distributed storage system to manage the VM images. In this paper, we design a distributed storage system, VMStore, by taking into account three important characteristics: high performance VM snapshot, booting optimization from multiple images and redundancy removal of images data. We adopt a direct index structure of blocks for VM snapshots to speed up VM booting performance significantly; provide a distribute storage structure with good bandwidth scalability by dynamically changing the number of storage nodes; and propose a data preprocessing strategy with intelligent object partitioning techniques, which would eliminate duplication more effectively. Performance analysis for VMStore focuses on two metrics: the speedup of VM booting and the overhead of de-duplication. Experimental results show the efficiency and effectiveness of VMStore.
Recent advance of virtualization technology provides a new approach to check-point/restart at the virtual machine(VM) *** contrast to traditional process-level checkpointing,checkpointing at the virtualization layer b...
详细信息
Recent advance of virtualization technology provides a new approach to check-point/restart at the virtual machine(VM) *** contrast to traditional process-level checkpointing,checkpointing at the virtualization layer brings up several advantages,such as compatibility,transparence,flexibility and ***,because the virtualization layer has little semantic knowledge about the operation {1. and the applications running atop,VM-layer checkpointing requires saving the entire operating {1. state rather than a single *** overhead may render the approach *** reduce the size of VM checkpoint,in this paper we propose a page eviction scheme and an incremental checkpointing mechanism to avoid saving unnecessary VM pages in the *** keep the {1. online transparently,we propose a live checkpointing mechanism by saving the memory image in a copy-on-write(COW) *** implement the performance optimization mechanisms in a prototype {1.,called *** results with a group of representative applications show that our page eviction scheme and incremental checkpointing can significantly reduce the checkpoint file size by up to 87% and shorten the total checkpointing/restart time by a factor of up to 71.,in comparison with the Xens default checkpointing *** observed application downtimes due to checkpointing can be reduced to as small as 300 ms.
Skyline query processing has recently received a lot of attention in database *** a set of multi-dimensional objects,the skyline query finds the objects that are not dominated by *** the best of our knowledge,the exis...
详细信息
Skyline query processing has recently received a lot of attention in database *** a set of multi-dimensional objects,the skyline query finds the objects that are not dominated by *** the best of our knowledge,the existing researches mainly focus on how to efficiently return the whole skyline ***,as the cardinality and dimensionality of input dataset increase,the number of skylines grows exponentially,and hence this "huge" skyline set is completely useless to *** by the above fact,in this paper,we present a novel type of l-SkyDiv query,which only returns l skylines having maximum diversity,to improve the usefulness of skyline ***,we prove that the l-SkyDiv query belongs to the NP-Hard problem theoretically,and propose three efficient heuristic algorithms whose time complexities are polynomial to fast implement the proposed ***,we present detailed theoretical analyses and extensive experiments,demonstrating that our algorithms are both efficient and effective.
We revisited ab initio evaluations of the energy barriers along the possible diffusion paths of the defects in rutile TiO2. By using a method carefully considering the cancellation of the self-interaction, Ti intersti...
详细信息
作者：
COONEY, JMJohn M. Cooney
Ph.D. was a manager in the Large Scale Chromatography Unit of Pharmacia Fine Chemicals AB Uppsala Sweden. He is a consultant with W.P.C. Associates and will be joining Fermentech Ltd. Storey's Gate Westminster London SW1P 3AY U.K.REFERENCES Sumner J.B.1951. Urcase p. 873-892. In:The Enzymes Part 2. J.B. Sumner and K. Myrbä ck (eds.). Academic Press
New York.Martin A.J.P. and Synge R.L.M.1945. Analytical chemistry of the proteins p. 1-83. InAdvances in Protein Chemistry Vol. 2. M.L. Anson and J.T. Edsall (eds.). Academic Press New York.Fankuchen I.1945. X-ray diffraction and protein structure p. 387-405. InAdvances in Protein Chemistry Vol. 2. M.L. Anson and J.T. Edsall (eds.). Academic Press New York.Tristram G.R.1949. Amino acid composition of purified proteins p. 83-153. InAdvances in Protein Chemistry Vol. 5. M.L. Anson J.T. Edsall and K. Bailey (eds.). Academic Press New York.|ISI|Sanger F.1952. The arrangement of amino acids in proteins p. 1-67. InAdvances in Protein Chemistry Vol. 7. M.L. Anson K. Bailey and J.T. Edsall (eds.). Academic Press New York.Tristram G.R.1953. The amino acid composition of proteins p. 181-233. InThe Proteins Vol. 1A. H. Neurath and K. Bailey (eds.). Academic Press New York.Low B.W.1953. The structure and configuration of amino acids peptides and proteins p. 235-391. InThe Proteins Vol. 1A. H. Neurath and K. Bailey (eds.). Academic Press New York.Sanger F.1949. Fractionation of oxidized insulin. Biochem. J.44: 126-128.|ISI|ChemPort|Sanger F. and Tuppy H.1951. The amino acid sequence in the phenylalanyl chain of insulin. 1. The identification of lower peptides from partial hydrolysates. Biochem. J.49: 463-481.|PubMed|ISI|ChemPort|Sanger F. and Tuppy H.1951. The amino acid sequence in the phenylalanyl chain of insulin. 2. The investigation of peptides from enzymic hydrolysates. Biochem. J.49: 481-490.|PubMed|ISI|ChemPort|Sanger F. and Thompson E.O.P.1953. The amino acid sequence in the glycyl chain of
暂无评论