the management of privacy and security in the context of data stream management systems (DSMS) remains largely an unaddressed problem to date. Unlike in traditional DBMSs where access control policies are persistently...
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ISBN:
(纸本)9781424418367;1424418364
the management of privacy and security in the context of data stream management systems (DSMS) remains largely an unaddressed problem to date. Unlike in traditional DBMSs where access control policies are persistently stored on the server and tend to remain stable, in streaming applications the contexts and withthem the access control policies on the real-time data may rapidly change. A person entering a casino may want to immediately block others from knowing his current whereabouts. We thus propose a novel ";stream-centric"; approach, where security restrictions are not persistently stored on the DSMS server, but rather streamed together withthe data. Here, the access control policies are expressed via security constraints (called security punctuations, or short, sps) and are embedded into data streams. the advantages of the sp model include flexibility, dynamicity and speed of enforcement. DSMSs can adapt to not only data-related but also security-related selectivities, which helps reduce the waste of resources, when few subjects have access to data. We propose a security-aware query algebra and new equivalence rules together with cost estimations to guide the security-aware query plan optimization. We have implemented the sp framework in a real DSMS. Our experimental results show the validity and the performance advantages of our sp model as compared to alternative access control enforcement solutions for DSMSs.
Data warehouses (DWs) have traditionally been loaded with data at regular time intervals, e.g., monthly, weekly, or daily, using fast bulk loading techniques. Recently, the trend is to insert all (or only some) new so...
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ISBN:
(纸本)9781424418367;1424418364
Data warehouses (DWs) have traditionally been loaded with data at regular time intervals, e.g., monthly, weekly, or daily, using fast bulk loading techniques. Recently, the trend is to insert all (or only some) new source data very quickly into DWs, called near-realtime DWs (right-time DWs). this is done using regular INSERT statements, resulting in too low insert speeds. there is thus a great need for a solution that makes inserted data available quickly, while still providing bulk-load insert speeds. this paper presents RiTE ("Right-Time ETL"), a middleware system that provides exactly that. A data producer (ETL) can insert data that becomes available to data consumers on demand. RiTE includes an innovative main-memory based catalyst that provides fast storage and offers concurrency control. A number of policies controlling the bulk movement of data based on user requirements for persistency, availability, freshness, etc. are supported. the system works transparently to both producer and consumers. the system is integrated with an open source DBMS, and experiments show that it provides "the best of both worlds", i.e., INSERT-like data availability, but with bulk-load speeds (up to 10 times faster).
Network traffic monitoring have been gaining attentions due to its importance in telecom industry. However, the monitoring systems deployed in telecom operators are usually too slow because of their disk-based process...
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ISBN:
(纸本)9781424418367;1424418364
Network traffic monitoring have been gaining attentions due to its importance in telecom industry. However, the monitoring systems deployed in telecom operators are usually too slow because of their disk-based processing approach. To address this problem, an online network traffic monitoring system, named SMART, is designed and developed. the system converts different formats of raw Netflow data (Netflow IPv5, IPv7 and IPv9) to user-defined control flows through combination and filtering. It can compute top-k frequent flows with sliding window, detects burst on arbitrary attributes, and presents results visually to users. the system could be used to replace the traditional offline monitoring system used in Shanghai Telecom. In its daily operation, it is shown that the processing speed achieves 30,000 flows per second. the basis of advanced streaming algorithms and design of robust system architecture enable SMART to achieve good performance.
Proportional data (normalized histograms) have been frequently occurring in various areas, and they could be mathematically abstracted as points residing in a geometric simplex. A proper distance metric on this simple...
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ISBN:
(纸本)9781595937933
Proportional data (normalized histograms) have been frequently occurring in various areas, and they could be mathematically abstracted as points residing in a geometric simplex. A proper distance metric on this simplex is of importance in many applications including classification and information retrieval. In this paper, we develop a novel framework to learn an optimal metric on the simplex. Major features of our approach include: 1) its flexibility to handle correlations among bins/dimensions;2) widespread applicability without being limited to ad hoc backgrounds;and 3) a "real" global solution in contrast to existing traditional local approaches. the technical essence of our approach is to fit a parametric distribution to the observed empirical data in the simplex. the distribution is parameterized by affinities between simplex vertices, which is learned via maximizing likelihood of observed data. then, these affinities induce a metric on the simplex, defined as the earth mover's distance equipped with ground distances derived from simplex vertex affinities.
Many projects have failed badly and become very costly to the organizations concerned. Project Management systems (PMS) are expected to help project managers and the team members to manage their projects more effectiv...
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ISBN:
(纸本)0889865744
Many projects have failed badly and become very costly to the organizations concerned. Project Management systems (PMS) are expected to help project managers and the team members to manage their projects more effectively and reduce the risks of failure. this study examines the typical problems in PMS, which have led to ineffective project management. A prototype of a web-based PMS with strong control mechanisms has been developed to address these problems. Further analysis, implications and future direction of PMS are also discussed.
this paper assesses the real usefulness of CRCs in today's satellite network-to-link adaptation layers under the lights of enhanced error control and framing techniques, focusing on the DVB-S and DVB-S2 standards....
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ISBN:
(纸本)1563478161
this paper assesses the real usefulness of CRCs in today's satellite network-to-link adaptation layers under the lights of enhanced error control and framing techniques, focusing on the DVB-S and DVB-S2 standards. Indeed, the outer block codes of their FEC schemes (Reed-Solomon and BCH. respectively) can provide very accurate error-detection information to the receiver in addition to their correction capabilities, at virtually no cost. this handy feature could be used to manage on a frame-by-frame basis what CRCs do locally, on the frames' contents, saving the bandwidth and processing load associated withthem, and paving the way for enhanced transport of IP over DVB-S2. Mathematical and experimental results clearly show that if FEC has been properly configured for combined error correction and detection, having an uncorrected event after FEC decoding is likely to be an extremely improbable event. Under such conditions, it seems possible and attractive to optimize the way global error-control is done over satellite links by reducing the role of CRCs, or even by removing them from the overall encapsulation process.
A new technique for power management problem of complex systems will be introduced in this paper. We model a power-managed distributed computing system. We use the Normal distribution to optimization. Experimental res...
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A new technique for power management problem of complex systems will be introduced in this paper. We model a power-managed distributed computing system. We use the Normal distribution to optimization. Experimental results show that the proposed technique can achieve more than 13% power saving compared to other existing DPM techniques.
In the course of modernisation within public authorities, governmental processes are being improved and made more cost efficient. this can be done by adapting techniques already successfully used in the private sector...
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In the course of modernisation within public authorities, governmental processes are being improved and made more cost efficient. this can be done by adapting techniques already successfully used in the private sector. Legal restrictions in data access as well as the cooperation of authorities in non-hierarchical networks, however, require a different approach to this subject. In this paper, the execution of workflows arising in e-Government, is analysed and problem areas that arise out of the distributedness and heterogeneity of communicating systems are described. Furthermore a distributed architecture for workflow systems and protocols solving these problems are proposed.
A distributed algorithm for the multihop wireless sensor networks is proposed to construct a novel energy efficient tree topology. the topology is constructed, without taking location information of the sensor nodes a...
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