A key issue to reduce the number of deadline misses and improve energy savings in embeddedreal-timesystems is to accurately estimate the execution time of tasks as a function of the processor frequency. Existing exe...
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ISBN:
(纸本)9781479961238
A key issue to reduce the number of deadline misses and improve energy savings in embeddedreal-timesystems is to accurately estimate the execution time of tasks as a function of the processor frequency. Existing execution time models however, use to rely on off-line analysis or on the assumption that the memory access time (quantified in processor cycles) is constant, ignoring that memory system components are not affected by the processor clock. In this paper, we propose the Processor-Memory (Proc-Mem) model, which dynamically predicts the execution time of the applications running in a multicore processor when varying the processor frequency. Proc-Mem approach is compared with a typical Constant Memory Access time model, namely CMAT. Results show that the deviation of Proc-Mem is always lower than 6% with respect to the measured execution time, while the deviation of the CMAT model always exceeds 30%. these results turn in important energy savings for a similar number of deadline misses. Energy savings are on average by 22.9%, and up to 47.8% in the studied mixes.
Smart grid technology is progressing worldwide. Various Countries are investing to transform their traditional power grid to Smart grid. they have started realigning their organization to support a Smart grid vision. ...
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Smart grid technology is progressing worldwide. Various Countries are investing to transform their traditional power grid to Smart grid. they have started realigning their organization to support a Smart grid vision. At this initial stage some software models are required to quantify; evaluate, monitor the progress and plan for the realization of a smart grid. this paper provides a detailed description of the steps involved in the design of an embedded data acquisition based on Linux. embedded board based on Linux operating system such as BeagleBone is used to develop a modern web page for data collection using PHP and Mysql.
this study designs and implements an embedded system-based distributed private cloud (EBDPC), which is a real-time analyzing device used in a wireless sensor network (WSN) monitoring system application. the proposed s...
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ISBN:
(纸本)9781479961238
this study designs and implements an embedded system-based distributed private cloud (EBDPC), which is a real-time analyzing device used in a wireless sensor network (WSN) monitoring system application. the proposed system consists of several low cost embeddedsystems for the detection, classification, and measurement of six types of power quality events, including impulse, voltage sag, voltage swell, interruption, harmonics, and flicker. Fast Fourier Transform (FFT) methods are used for automatic signal classification and characterization, and real-time notification for disturbance detection. A light-weighted load balance algorithm is also included in the proposed system for handling a great amount of data collected from electric sensors. the system has been successfully applied to detecting, classifying, and measuring disturbances in a power quality monitoring WSN.
Since the beginning of the ubiquitous computing era, context-aware applications have been envisioned and pursued, with location and especially proximity information being one of the primary building blocks. To date, t...
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ISBN:
(纸本)9781467377027
Since the beginning of the ubiquitous computing era, context-aware applications have been envisioned and pursued, with location and especially proximity information being one of the primary building blocks. To date, there is still a lack of feasible solutions to perform proximity tests between mobile entities in a privacy-preserving manner, i.e., one that does not disclose one's location in case the other party is not in proximity. In this paper, we present our novel approach based on location tags built from surrounding Wi-Fi signals originating only from mobile devices. Since the set of mobile devices at a given location changes over time, this approach ensures the user's privacy when performing proximity tests. To improve the robustness of similarity calculations, we introduce a novel extension of the commonly used cosine similarity measure to allow for weighing its components while preserving the signal strength semantics. Our system is evaluated extensively in various settings, ranging from office scenarios to crowded mass events. the results show that our system allows for robust short-range proximity detection while preserving the participants' privacy.
One approach for real-time scheduling on multicore platforms involves task partitioning, which statically assigns tasks to cores, enabling subsequent core-local scheduling. No past partitioning schemes explicitly cons...
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ISBN:
(纸本)9781479961238
One approach for real-time scheduling on multicore platforms involves task partitioning, which statically assigns tasks to cores, enabling subsequent core-local scheduling. No past partitioning schemes explicitly consider cache effects. We present a partitioning scheme called LWFG, which minimizes cache misses by partitioning tasks that share memory onto the same core and by evenly distributing the total working set size across cores. Our implementation reveals that LWFG improves execution efficiency and reduces mean maximum tardiness over past works by as much as 15% and 60%, respectively.
the coarse-grained reconfigurable architecture (CGRA) is proven to be energy efficient in many domains, such as multi-media and signal processing. However, the continuous updating of configuration context limits the p...
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the coarse-grained reconfigurable architecture (CGRA) is proven to be energy efficient in many domains, such as multi-media and signal processing. However, the continuous updating of configuration context limits the performance of reconfigurable systems severely. Configuration context cache is usually introduced in CGRAs to solve this problem. this paper proposes several methods to improve the performance of the configuration context cache. Firstly, the configuration context is classified into three levels. Secondly, a three-level hierarchical cache structure, based on the Pre-fetch and Hybrid-Priority strategies, is adopted to reduce the cache accessing time. Finally, a novel Two-Side-View design, including the physical view and the logic view, is implemented to reduce the cache size. the experimental results show that the proposed structure is 2.23 times and 2.06 times better than the up-to-date centralized and distributed structures. the proposed cache structure has been integrated in a reconfigurable computing processor called REMUS-II. When processing multi-media applications, REMUS-II can realize 1080p HiP@30fps decoding at frequency of 200MHz.
Virtualization techniques are gaining significant interests in embeddedreal-time system design. However, existing virtualization platforms lack strong performance isolation among virtual machines. In this work we pro...
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ISBN:
(纸本)9781479939534
Virtualization techniques are gaining significant interests in embeddedreal-time system design. However, existing virtualization platforms lack strong performance isolation among virtual machines. In this work we propose a method to monitor and control the shared memory accesses of individual virtual machines on multi-core processors with Xen hypervisor, to enhance the performance isolation among virtual machines and improve the timing predictability of real-timeapplications. Experiments withthe SPEC2006 benchmark programs are conducted to validate the proposed method.
In recent years, IT Service Providers have been rapidly introducing automation to their service delivery model. Driven by market pressure to reduce cost and maintain quality of services, they are looking for technolog...
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ISBN:
(纸本)9781467378574
In recent years, IT Service Providers have been rapidly introducing automation to their service delivery model. Driven by market pressure to reduce cost and maintain quality of services, they are looking for technologies that will allow rapid progress towards attainment of truly automated service delivery. Software monitoring systems are designed to actively collect and signal event occurrences and, when necessary, automatically generate incident tickets. Repeating events generate similar tickets, which in turn have a vast number of repeated problem resolutions likely to be found in earlier tickets. In our work, we develop techniques to recommend an appropriate resolution for incoming events by making use of similarities between the events and historical resolutions of similar events. the traditional KNN (K Nearest Neighbor) algorithm has been first applied to recommend resolutions for incoming tickets. Massive heterogeneous applications as well as various monitoring software are running on clients' servers to accomplish required tasks and to monitor system health via different metrics. It leads to generation of correlated tickets that have different symptom descriptions but similar resolutions. Furthermore, change of servers' environments can also induce similar situations in which ticket descriptions differ before and after change but could have similar resolutions. these correlated tickets cause performance degradation in ticket resolution recommendation. therefore, we propose using SCL (structural corresponding learning) based feature adaptation to uncover feature mapping in different time intervals. Moreover, to put more insights into the periodic regularities existing in our ticket datasets, we apply our algorithm on tickets grouped by different time interval granularities. Extensive empirical evaluations on real-world ticket data sets demonstrate the effectiveness and efficiency of our proposed methods.
In order to support the end-to-end timing analysis at various abstraction levels and development phases, the end-to-end timing models should be extracted from models of the applications in such a way that they are int...
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ISBN:
(纸本)9781479931873
In order to support the end-to-end timing analysis at various abstraction levels and development phases, the end-to-end timing models should be extracted from models of the applications in such a way that they are interoperable. We discuss the challenges and issues that are faced when the timing models are extracted at various abstraction levels during model-and component-based development of vehicular distributed embeddedsystems. We also present preliminary guidelines and solutions to address these challenges.
A task migration method is proposed for energy savings in multiprocessor real-timesystems. the method is based on the portioned scheduling technique which classifies each task into a fixed task or a migratable task. ...
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ISBN:
(纸本)9781479961238
A task migration method is proposed for energy savings in multiprocessor real-timesystems. the method is based on the portioned scheduling technique which classifies each task into a fixed task or a migratable task. the energy-aware migration with specified parameters is formulated as a linear programming problem, and optimal solution is given. Furthermore, the method is extended to more general case with a complete migration algorithm. Simulation results showed significant energy savings over existing methods.
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