In this paper, we discuss the performance of the affine projection CM algorithm, which can deal with the cases that the input signals are correlated and decrease the filtering error. We describe the derivation of algo...
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We analyze push and pull for data collection in wireless sensor networks. Most applications to date use the traditional push approach, where nodes transmit sensed data immediately to the sink. Using a pull approach, n...
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ISBN:
(纸本)9781450303446
We analyze push and pull for data collection in wireless sensor networks. Most applications to date use the traditional push approach, where nodes transmit sensed data immediately to the sink. Using a pull approach, nodes store the data in their local flash memory, and only engage in communication during dedicated collection phases. We show how one can transform an existing push-based collection protocol into a pull-based one, and compare the power consumption of both approaches on a 35-node testbed. Our results show that substantial energy gains are possible with pull, provided that the application can tolerate a long latency. Copyright 2010 ACM.
We propose a novel wavelength-division multiplexed passive optical network （WDM-PON） to simultaneously transmit unicast data and multicast services with upstream data re-modulation in optical network units （ONUs）....
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We propose a novel wavelength-division multiplexed passive optical network （WDM-PON） to simultaneously transmit unicast data and multicast services with upstream data re-modulation in optical network units （ONUs）. For each wavelength channel in the optical line terminal （OLT）, the downstream unicast data are applied to one arm of a dual-parallel Mach-Zehnder modulator （DPMZM） to generate baseband unicast non-return-to-zero （NRZ） signal. A radio frequency （RF） control signal is applied to the other arm to present two un-modulated sidebands for multicast data modulation in a differential phase-shift keying （DPSK） format. The flexible and dynamic multicast services are realized by simply switching the RF control signal on or off. The proposed scheme is experimentally demonstrated with 1.25-Gb/s downstream unicast, multicast, and upstream data.
The existing service migration methods bring the server cluster heavy burden, and their time spending is so high that seriously affects the service continuity. In order to enhance the survivability of IP network servi...
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The existing service migration methods bring the server cluster heavy burden, and their time spending is so high that seriously affects the service continuity. In order to enhance the survivability of IP network services, the paper puts forward an intent-perceptible service migration model (ISM). In this model, we design a novel trigger mechanism and object selecting method for service migration, and make the service migration intention perceptible for the client with the cooperation of the server. The evaluation results show that ISM model can not only ensure the service invulnerability by maintaining a high randomness of service migration, but also improve the service continuity by reducing the service gap time spending on service migration to the maximum extent. Therefore, ISM model can enhance IP network survivability efficiently.
Commercial, coin-sized iButton temperature logger devices are well-suited for densely instrumenting large outdoor areas. An efficient workflow for deploying and maintaining those devices is necessary when striving to ...
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ISBN:
(纸本)9781450303446
Commercial, coin-sized iButton temperature logger devices are well-suited for densely instrumenting large outdoor areas. An efficient workflow for deploying and maintaining those devices is necessary when striving to deploy and operate several hundreds of data logger devices. Additionally, a sophisticated data management is required for handling the emerging, large amounts of meta and measurement data. Therefore, we developed iAssist, a solution that integrates the handling of iButton data logger devices together with a GPS receiver and a digital camera for gathering accurate location information. iAssist efficiently supports the whole workflow consisting of deploying, relocating and reading tiny sensing systems. iAssist is especially tailored for outdoor operation asking for as little user interaction as possible. Copyright 2010 ACM.
Wireless Sensor networks (WSNs) are unique embedded computer systems for distributed sensing of a dispersed phenomenon. As WSNs are deployed in remote locations for longterm unattended operation, assurance of correct ...
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Many sensor network systems encounter considerable problems after deployment despite extensive simulation and testing during the development. A fundamental issue is unforeseen problems that rarely occur, which makes t...
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Due to their embedding into an unknown environment, wireless sensor networks are susceptible to adverse environmental conditions. A prime example is external interference, typically caused by 802.11, electric devices ...
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Embedded control systems in automobiles are typically implemented by a set of tasks deployed on multiple Electronic Control Units (ECUs) communicating via one or more buses like CAN or FlexRay. In the case of safety-c...
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ISBN:
(纸本)9781605589046
Embedded control systems in automobiles are typically implemented by a set of tasks deployed on multiple Electronic Control Units (ECUs) communicating via one or more buses like CAN or FlexRay. In the case of safety-critical systems, there are hard real-time bounds on the (i) response times of tasks/messages, and (ii) end-to-end latencies of certain task/message chains. These depend on various factors like the number of tasks (and messages) involved in the processing (and communication) sequence, parameters of these tasks/messages, scheduling policies, communication protocols, clock drifts, etc. Moreover, since the data transfer among tasks/messages is typically via asynchronous buffers that are overwritable and sticky, multiple semantics are possible for end-to-end latency. Hence, precise estimation of response times and end-to-end latencies in embedded systems is a non-trivial problem. In this paper, we propose a model-checking based technique to compute worst-case response times and end-to-end latencies. We consider a distributed system made of preemptively scheduled tasks and non-preemptively scheduled messages. Given a chain in the system, we estimate two different end-to-end latencies -LIFO and LILO- which are important in automotive domain. From a system description, we automatically synthesize a formal model based on a discrete event simulation formalism called Calendar Automata. It is then model-checked to compute response times and end-to-end latencies. Our technique is more scalable than the existing formal methods based techniques. We have illustrated this technique on reasonably large case-studies from the automotive domain.
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