Localization of sources of brain electrical activity from electroencephalographic and magnetoencephalographic recordings is an ill-posed inverse problem. Therefore, the best one can hope for is to derive a source loca...
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We present a programming methodology and runtime performance case study comparing the declarative data flow coordination language S-Net with Intel's Concurrent Collections (CnC). As a coordination language S-Net a...
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ISBN:
(纸本)9781479941155
We present a programming methodology and runtime performance case study comparing the declarative data flow coordination language S-Net with Intel's Concurrent Collections (CnC). As a coordination language S-Net achieves a near-complete separation of concerns between sequential software components implemented in a separate algorithmic language and their parallel orchestration in an asynchronous data flow streaming network. We investigate the merits of S-Net and CnC with the help of a relevant and non-trivial linear algebra problem: tiled Cholesky decomposition. We describe two alternative S-Net implementations of tiled Cholesky factorization and compare them with two CnC implementations, one with explicit performance tuning and one without, that have previously been used to illustrate Intel CnC. Our experiments on a 48-core machine demonstrate that S-Net manages to outperform CnC on this problem.
As computing becomes ubiquitous, researchers and engineers aim to exploit the potential of the pervasive systems in order to introduce new types of services and address inveterate and emerging problems. This process w...
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As computing becomes ubiquitous, researchers and engineers aim to exploit the potential of the pervasive systems in order to introduce new types of services and address inveterate and emerging problems. This process will, eventually, lead us to the era of urban computing and the Internet of Things; the ultimate goal being to improve our quality of life. But these concepts typically require direct and constant interaction of computing systems with the physical world in order to be realized, which inevitably leads to the introduction of a range of safety and privacy issues that must be addressed. One such important aspect is the fine-grained control of access to the resources of these pervasive embedded systems, in a secure and scalable manner. This paper presents an implementation of such a secure policy-based access control scheme, focusing on the use of well-established, standardized technologies and considering the potential resource-constraints of the target heterogeneous embedded devices. The proposed framework adopts a DPWS-compliant approach for smart devices and introduces XACML-based access control mechanisms. The proof-of-concept implementation is presented in detail, along with a performance evaluation on typical embedded platforms.
In this paper we identify basic design issues of Mobile Crowdsensing Systems (MCS) and investigate some characteristic challenges. We define the basic components of an MCS - the Task, the Server and the Crowd - and in...
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In this paper we identify basic design issues of Mobile Crowdsensing Systems (MCS) and investigate some characteristic challenges. We define the basic components of an MCS - the Task, the Server and the Crowd - and investigate the functions describing/governing their interactions. We identify three qualitatively different types of Tasks; a) those whose added utility is proportional to the size of the Task, b) those whose added utility is proportional to the progress of the Task and c) those whose added utility is reversely proportional to the progress of the Task. For a given type of Task, and a finite Budget, the Server makes offers to the agents of the Crowd based on some Incentive Policy. On the other hand, each agent that receives an offer decides whether it will undertake the Task or not, based on the inferred cost (computed via a Cost function) and some Join Policy. In their policies, the Crowd and the Server take into account several aspects, such as the number and quality of participating agents, the progress of execution of the Task and possible network effects, present in real-life systems. We evaluate the impact and the performance of selected characteristic policies, for both the Crowd and the Server, in terms of Task execution and Budget efficiency of the Crowd. Experimental findings demonstrate key performance features of the various policies and indicate that some policies are more effective in enabling the Server to efficiently manage its Budget while providing satisfactory incentives to the Crowd and effectively executing the system Tasks. Interestingly, incentive policies that take into account the current crowd participation achieve a better trade-off between Task completion and budget expense.
The intense environmental concern regarding the CO 2 footprint of the energy sector entails the higher Renewable Energy Sources (RES) share in the energy mix of the global production profile. Currently, energy is pro...
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The intense environmental concern regarding the CO 2 footprint of the energy sector entails the higher Renewable Energy Sources (RES) share in the energy mix of the global production profile. Currently, energy is produced and distributed under a centralized framework preventing small electricity producers from participating in the electricity market, unless they are part of larger energy associations, the administration of which necessitates the exploitation of new energy and ICT technologies. The VIMSEN project introduces a highly dynamic and distributed market framework, in which new market players will emerge and the current energy market ecosystem will be modified. The framework is primarily based on the concept of Virtual Micro-Grids (VMGs) and on the active participation of renewable energy prosumers. This position paper aims to analyze the VIMSEN ecosystem in a conceptual way and introduce novel market actors as well as their responsibilities that enable the implementation of beyond state-of-the-art ICT frameworks and business models in future liberalized energy markets.
In the bounded storage model the memory of the adversarial parties is restricted, instead of their computational power. This different restriction allows the construction of protocols with information-theoretical (ins...
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In the bounded storage model the memory of the adversarial parties is restricted, instead of their computational power. This different restriction allows the construction of protocols with information-theoretical (instead of only computational) security. We present the first protocol for oblivious transfer in the bounded storage model with errors, i.e., where the public random sources available to the two parties are not exactly the same, but instead are only required to have a small Hamming distance between themselves, and the memory of the (adversarial) receiver is limited. Oblivious transfer protocols were known previously only for the error-free variant of the bounded storage model, which is harder to realize.
Next-generation wireless networks integrate multiple wireless access technologies to provide seamless wireless connectivity for mobile nodes (MNs). When MNs move in wireless heterogeneous networks, they may suffer fro...
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ISBN:
(纸本)9781479973958
Next-generation wireless networks integrate multiple wireless access technologies to provide seamless wireless connectivity for mobile nodes (MNs). When MNs move in wireless heterogeneous networks, they may suffer from the great degradation of received signal strength (RSS) and further quality of services (QoS), if randomly selecting an access point (AP). We address vertical handoff with game theory to enable MNs to trigger the handoff and select an appropriate network from multiple wireless access technologies. On the other hand, the existing vertical handoff schemes lack of jointly considering the behaviors of MNs and APs for approaching the reality. To solve this problem, we propose a repeated game based scheme for vertical handoff. Each sub-game is formulated as a non-cooperative strategic game between a MN and an AP in which the Nash equilibrium is the solution of each strategic game. The proposed repeated game is to optimize the utility functions of the whole network by finding an equilibrium point. We perform the performance analysis, which shows that proposed scheme can achieve better bandwidth utilization and throughput of the network compared to the AP random selection scheme.
In recent years, there has been an increasing interest in Software Defined Networking (SDN)/OpenFlow, which is a novel network architecture splitting control and data planes. The SDN-enabled products have also been wi...
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In recent years, there has been an increasing interest in Software Defined Networking (SDN)/OpenFlow, which is a novel network architecture splitting control and data planes. The SDN-enabled products have also been widely deployed in many production networks aiming to bypass the limitations of current Internet architecture. There are several efforts on building Software Defined Routing Platform (SDRP), which integrates SDN/OpenFlow within IP routing. However, to the best of our knowledge, there are a few successful works on realizing SDRP despite of the flexibility and rich features of SDN. In this paper, we investigate state-of-the-art works towards SDRP. We have evaluated the performance of a mainstream SDRP named RouteFlow. Our evaluations have been conducted using both the emulator Mininet and a real testbed with physical switches. Different to other works, we focus on the resilience aspect of the routing platform. The evaluation results show that RouteFlow is resilient against both single and multiple link failures. Additionally, OSPF provided by RouteFlow achieves a shorter failover time than the legacy OSPF. In the case of RIPv2, RouteFlow's protocol has a comparable performance value with the distributed one.
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