In recent years, Web services has represented a more loosely coupled distributed application structure and provided more effective ways for applications to interoperate in open and dynamic environment. Web services co...
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In recent years, Web services has represented a more loosely coupled distributed application structure and provided more effective ways for applications to interoperate in open and dynamic environment. Web services composition is one of the most popular topics in service computing area. The traditional composition methods are always centralized control and services are composed passively, therefore, it is difficult to adapt the open and dynamic environment and there are defects about autonomy and self-adaptation. In this paper an Agent organization based adaptive Web services composition method is proposed and adaptive algorithms are introduced. The capability of self-adaptation of Agents can be guaranteed with these algorithms.
In recent years,Web services has represented a more loosely coupled distributed application structure and provided more effective ways for applications to interoperate in open and dynamic *** services composition is o...
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In recent years,Web services has represented a more loosely coupled distributed application structure and provided more effective ways for applications to interoperate in open and dynamic *** services composition is one of the most popular topics in service computing area. The traditional composition methods are always centralized control and services are composed passively,therefore,it is difficult to adapt the open and dynamic environment and there are defects about autonomy and *** this paper an Agent organization based adaptive Web services composition method is proposed and adaptive algorithms are *** capability of self-adaptation of Agents can be guaranteed with these algorithms.
Traditionally, video adaptive algorithms aim to select the representation that better fits to the current download rate. In recent years, a number of new approaches appeared that take into account the buffer occupancy...
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Traditionally, video adaptive algorithms aim to select the representation that better fits to the current download rate. In recent years, a number of new approaches appeared that take into account the buffer occupancy and the probability of video rebuffering as important indicators of the representation to be selected. We propose an optimization of the existing algorithm based on rebuffering probability and argue that the algorithm should avoid the situations when the client buffer is full and the download is stopped, since these situations decrease the efficiency of the algorithm. Reducing full buffer states does not increase the rebuffering probability thanks to a clever management of the client buffer, which analyses the buffer occupancy and downloads higher bitrate representations only in the case of high buffer occupancy.
Quality-critical production processes influence the final product quality significantly. There is an increasing demand for highly accurate product quality monitoring systems to reduce time- and cost-intensive product ...
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Quality-critical production processes influence the final product quality significantly. There is an increasing demand for highly accurate product quality monitoring systems to reduce time- and cost-intensive product inspections. This paper proposes a data-driven product quality monitoring system for execution on devices with low computational power in production environments. Particularly for quality-critical processes, the developed monitoring approach promises to deliver high accuracy. It is based on building a regression model to describe a quality indicator dependent on sensor data. The developed approach is addressed to highly variable production processes with a minimal set of reference data in which the quality assessment must be available in a timely manner. This small set of reference data is used for model building. Therefore, it is estimated that the regression model tends to deliver limited predictive power. The authors consider semi-optimal models explicitly and design a quality classifier sensitive to the prediction model’s predictive power. The presented approach is evaluated on historical data for a use case from powder metallurgy. Furthermore, the approach for product quality monitoring under consideration of semi-optimal regression models provides a one hundred percent accuracy in an exemplary test case. It is shown that the model’s predictive power in quality monitoring must be considered to design monitoring systems with high accuracy.
Much research has been conducted on energy management for memory and disks. Most studies use control algorithms that dynamically transition devices to low power modes after they are idle for a certain threshold period...
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ISBN:
(纸本)9781581138047
Much research has been conducted on energy management for memory and disks. Most studies use control algorithms that dynamically transition devices to low power modes after they are idle for a certain threshold period of time. The control algorithms used in the past have two major limitations. First, they require painstaking, application-dependent manual tuning of their thresholds to achieve energy savings without significantly degrading performance. Second, they do not provide performance guarantees. In one case, they slowed down an application by *** paper addresses these two limitations for both memory and disks, making memory/disk energy-saving schemes practical enough to use in real systems. Specifically, we make three contributions: (1) We propose a technique that provides a performance guarantee for control algorithms. We show that our method works well for all tested cases, even with previously proposed algorithms that are not performance-aware. (2) We propose a new control algorithm, Performance-directed Dynamic (PD), that dynamically adjusts its thresholds periodically, based on available slack and recent workload characteristics. For memory, PD consumes the least energy, when compared to previous hand-tuned algorithms combined with a performance guarantee. However, for disks, PD is too complex and its self-tuning is unable to beat previous hand-tuned algorithms. (3) To improve on PD, we propose a simple, optimization-based, threshold-free control algorithm, Performance-directed Static (PS). PS periodically assigns a static configuration by solving an optimization problem that incorporates information about the available slack and recent traffic variability to different chips/disks. We find that PS is the best or close to the best across all performanceguaranteed disk algorithms, including hand-tuned versions.
The paper proposes enhancements to adaptive video streaming over HTTP using a wireless bandwidth management architecture. The architecture enforces distributed control over video bitrate adaptation by providing additi...
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ISBN:
(纸本)9781509013296
The paper proposes enhancements to adaptive video streaming over HTTP using a wireless bandwidth management architecture. The architecture enforces distributed control over video bitrate adaptation by providing additional network-side control information to video clients in order to assist them in their decision-making. The architecture and included distributed decision algorithms are network and service aware thanks to a cross-layer signaling framework. The paper presents an MPEG-DASH based testbed implementation of the architecture and studies its performance in the context of two network-assisted video adaptation use cases. The results, obtained in an experimental evaluation conducted using the testbed, attest the benefits of the proposed solution against a state-of-the-art client-side approach.
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