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  • 1
    Electronic Resource
    Electronic Resource
    Data partitioning and load balancing in parallel disk systems (1998)
    Springer
    The VLDB journal 7 (1998), S. 48-66 
    Details
    ISSN: 0949-877X
    Keywords: Key words:Parallel disk systems – Performance tuning – File striping – Data allocation – Load balancing – Disk cooling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. Parallel disk systems provide opportunities for exploiting I/O parallelism in two possible ways, namely via inter-request and intra-request parallelism. In this paper, we discuss the main issues in performance tuning of such systems, namely striping and load balancing, and show their relationship to response time and throughput. We outline the main components of an intelligent, self-reliant file system that aims to optimize striping by taking into account the requirements of the applications, and performs load balancing by judicious file allocation and dynamic redistributions of the data when access patterns change. Our system uses simple but effective heuristics that incur only little overhead. We present performance experiments based on synthetic workloads and real-life traces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007780050053
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Evaluating the performance of algebraic operations on storage schemes for large sparse matrices (1988)
    Springer
    Engineering with computers 4 (1988), S. 121-134 
    Details
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract We study the performance of algebraic operations on large sparse matrices stored on secondary storage and show how the traditional algorithms can be fine-tuned in order to minimize the number of page accesses. We develop cost equations for performing multiplication, transposition, and Gaussian elimination on various secondary storage schemes for sparse matrices and show how these can be incorporated into a selection model which chooses the optimal sequence of storage schemes for a given mix of operations. Furthermore, we present the results of a number of experiments and compare our analytical results with experimental results obtained on synthetically generated data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01199294
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  • 3
    Electronic Resource
    Electronic Resource
    Web++ architecture, design and performance (2000)
    Springer
    World wide web 3 (2000), S. 65-77 
    Details
    ISSN: 1573-1413
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We describe the design of a system for fast and reliable HTTP service which we call Web++. Web++ achieves high reliability by dynamically replicating web data among multiple web servers. Web++ selects the available server that is expected to provide the fastest response time. Furthermore, Web++ guarantees data delivery given that at least one server containing the requested data is available. After detecting a server failure, Web++ client requests are satisfied transparently to the user by another server. Furthermore, the Web++ architecture is flexible enough for implementing additional performance optimizations. We describe implementation of one such optimization, batch resource transmission, whereby all resources embedded in an HTML page that are not cached by the client are sent to the client in a single response. Web++ is built on top of the standard HTTP protocol and does not require any changes either in existing web browsers or the installation of any software on the client side. In particular, Web++ clients are dynamically downloaded to web browsers as signed Java applets. We implemented a Web++ prototype; performance experiments indicate that the Web++ system with 3 servers improves the response time perceived by clients on average by 36.6%, and in many cases by as much as 59%, when compared with the current web performance. In addition, we show that batch resource transmission can improve the response time on average by 39% for clients with fast network connections and 21% for the clients with 56 Kb modem connections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019285730656
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  • 4
    Electronic Resource
    Electronic Resource
    MultidimensionalB-trees: Analysis of dynamic behavior (1981)
    Springer
    BIT 21 (1981), S. 401-418 
    Details
    ISSN: 1572-9125
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The MultidimensionalB-tree (MDBT) is a new method for multiple attribute indexing which uses B-trees to maintain the filial sets at each level and imposes an ordering on these filial sets in order to ensure efficient searching for various associative queries. In this paper, we show that the MDBT provides an attractive alternative to other indexing structures when frequent changes to the database occur. We present algorithms for maintaining the MDBT structure when insertions or deletions are posted which also account for some storage reclamation. Procedures for evaluating the average and worst-case times of our algorithms are given, showing that the maintenance of the MDBT structure can be done at a relatively low cost.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01932838
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  • 5
    Electronic Resource
    Electronic Resource
    A heuristic file reorganization algorithm based on record clustering (1989)
    Springer
    BIT 29 (1989), S. 428-447 
    Details
    ISSN: 1572-9125
    Keywords: H.0 ; H.2.2 ; H.3.3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The problem of file organization which we consider involves altering the placement of records on pages of a secondary storage device. In addition, we want this reorganization to be done in-place, i.e., using the file's original storage space for the newly reorganized file. The motivation for such a physical change is to improve the database system's performance. For example, by placing frequently and jointly accessed records on the same page or pages, we can try to minimize the number of page accesses made in answering a set of queeries. The optimal assignment (or reassignment) of records to clusters is exactly what record clustering algorithms attempt to do. However, record clustering algorithms usually do not solve the entire problem, i.e., they do not specify how to efficiently reorganize the file to reflect the clustering assignment which they determine. Our algorithm is a companion to general record clustering algorithms since it actually transforms the file. The problem of optimal file reorganization isNP-hard. Consequently, our reorganization algorithm is based on heuristics. The algorithm's time and space requirements are reasonable and its solution is near optimal. In addition, the reorganization problem which we consider in this paper is similar to the problem of join processing when indexes are used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02219229
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  • 6
    Electronic Resource
    Electronic Resource
    Adaptive Algorithms for Join Processing in Distributed Database Systems (1997)
    Springer
    Distributed and parallel databases 5 (1997), S. 233-269 
    Details
    ISSN: 1573-7578
    Keywords: distributed query processing ; join algorithms ; adaptive algorithms ; bipartite graphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Distributed query processing algorithms usually perform data reduction by using a semijoin program, but the problem with these approaches is that they still require an explicit join of the reduced relations in the final phase. We introduce an efficient algorithm for join processing in distributed database systems that makes use of bipartite graphs in order to reduce data communication costs and local processing costs. The bipartite graphs represent the tuples that can be joined in two relations taking also into account the reduction state of the relations. This algorithm fully reduces the relations at each site. We then present an adaptive algorithm for response time optimization that takes into account the system configuration, i.e., the additional resources available and the data characteristics, in order to select the best strategy for response time minimization. We also report on the results of a set of experiments which show that our algorithms outperform a number of the recently proposed methods for total processing time and response time minimization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008617911992
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  • 7
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    Tankyrase 1 Inhibitors with Drug-like Properties Identified by Screening a DNA-Encoded Chemical Library (2015)
    American Chemical Society (ACS)
    Details
    Publication Date: 2015-06-11
    Description: Journal of Medicinal Chemistry DOI: 10.1021/acs.jmedchem.5b00432
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society (ACS)
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  • 8
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    Quartz Solubility in the Two-Phase Region of the NaCl-H2O System: An Experimental Study With Application to the Piccard Hydrothermal Field, Mid-Cayman Rise (2018)
    American Geophysical Union
    Details
    Publication Date: 2018-09-11
    Description: Hydrothermal experiments were performed at elevated temperature (420–500 °C) and pressure (31.0–51.0 MPa) in the NaCl-H2O system to measure quartz solubility in coexisting vapor and liquid and extend the calibrated range of the Si-Cl geothermobarometer. In the vapor, the density-based equations for quartz solubility of Fournier (1983, http://doi.org/10.1016/0016-7037(83)90279-X) and Von Damm et al. (1991, http://doi.org/10.2475/ajs.291.10.977) agree well with the experimental data, while the equation of Fournier (1983) also accurately predicts SiO2(aq) concentrations in the liquid. Importantly, the equations of Fournier (1983) and Von Damm et al. (1991) were calibrated based on quartz solubility in single phase fluids (no coexisting vapor-liquid) at higher pressure than investigated here. The new experimental data therefore extend the pressure range of the density-equations and demonstrate that quartz solubility in either vapor or liquid can be treated independently as a function of temperature, pressure, and fluid density. The Si-Cl geothermobarometer indicates that fluids venting from Piccard reach 540 ± 15 °C, 62.5 ± 3.0 MPa. These are the hottest and deepest conditions yet recorded by an actively venting seafloor hydrothermal fluid. Based on the calculated enthalpy differences between the subsurface fluid and that venting at the seafloor, approximately one third of the heat extracted at depth is lost during conductive cooling of the hydrothermal fluid. Incorporating the heat lost during conductive cooling into the overall budget at Piccard yields a flux of 100 ± 37 MW and an associated hydrothermal fluid flux of 1.2 ± 0.4 × 109 kg/year. The newly calibrated Si-Cl geothermobarometer provides important constraints for accurate determination of heat and mass fluxes at axial vent sites. ©2018. American Geophysical Union. All Rights Reserved.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by American Geophysical Union
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  • 9
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    Efficient Maintenance of Continuous Queries for Trajectories (2007)
    Springer
    Details
    Publication Date: 2007-08-17
    Print ISSN: 1384-6175
    Electronic ISSN: 1573-7624
    Topics: Geography
    Published by Springer
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  • 10
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    Privacy-preserving detection of anomalous phenomena in crowdsourced environmental sensing using fine-grained weighted voting (2017)
    Springer
    Details
    Publication Date: 2017-07-05
    Print ISSN: 1384-6175
    Electronic ISSN: 1573-7624
    Topics: Geography
    Published by Springer
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