| 1. |
- Charalambous, Themistoklis, et al.
(author)
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Distributed Offline Load Balancing in MapReduce Networks
- 2013
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In: 2013 IEEE 52ND ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC). - : IEEE conference proceedings. ; , s. 835-840
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Conference paper (peer-reviewed)abstract
- In this paper we address the problem of balancing the processing load of MapReduce tasks running on heterogeneous clusters, i.e., clusters with different capacities and update cycles. We present a fully decentralized algorithm, based on ratio consensus, where each mapper decides the amount of workload data to handle for a single user job using only job specific local information, i.e., information that can be collected from directly connected neighboring mappers, regarding their current workload and capacity. In contrast to other algorithms in the literature, the proposed algorithm can be deployed in heterogeneous networks and can operate asynchronously in both directed and undirected communication topologies. The performance of the proposed algorithm is demonstrated via simulation experiments on large-scale strongly connected topologies.
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| 2. |
- Aminian, Behdad, et al.
(author)
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GISOO : A virtual testbed for wireless cyber-physical systems
- 2013
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In: Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE. - : IEEE. - 9781479902248 ; , s. 5588-5593
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Conference paper (peer-reviewed)abstract
- The increasing demand for wireless cyber-physical systems requires correct design, implementation and validation of computation, communication and control methods. Traditional simulation tools, which focus on either computation, communication or control, are insufficient when the three aspects interact. Efforts to extend the traditional tools to cover multiple domains, e.g., from simulating only control aspects to simulating both control and communication, often rely on simplistic models of a small subset of possible communication solutions. We introduce GISOO, a virtual testbed for simulation of wireless cyber-physical systems that integrates two state-of-the art simulators, Simulink and COOJA. GISOO enables users to evaluate actual embedded code for the wireless nodes in realistic cyber-physical experiments, observing the effects of both the control and communication components. In this way, a wide range of communication solutions can be evaluated without developing abstract models of their control-relevant aspects, and changes made to the networking code in simulations is guaranteed to be translated into production code without errors. A double-tank laboratory experimental setup controlled over a multi-hop relay wireless network is used to validate GISOO and demonstrate its features.
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| 3. |
- Björkbom, M., et al.
(author)
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Networked PID control : Tuning and outage compensation
- 2010
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In: IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics Society. - : IEEE. - 9781424452262 ; , s. 168-173
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Conference paper (peer-reviewed)abstract
- This paper deals with architecture and algorithm design of networked control systems (NCSs) to cope with network outages. A Networked PID controller and an internal model control based tuning scheme is proposed, using the jitter margin to ensure stability despite dropped packets. For longer periods of disconnection, an outage heuristic is proposed. The control design and outage heuristic need only the step response of the process and is as such simple to apply in practice. The effect of these outages on the stability and performance of the closed-loop control system are evaluated, and compared with alternative schemes via extensive simulations. The simple Networked PID with the outage heuristic is shown to perform well, compared to other techniques proposed in the NCS literature.
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| 4. |
- Ghadimi, Euhanna, et al.
(author)
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A metric for opportunistic routing in duty cycled wireless sensor networks
- 2012
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In: Sensor, Mesh and Ad Hoc Communications and Networks (SECON), 2012 9th Annual IEEE Communications Society Conference on. - : IEEE. - 2155-5486 .- 2155-5494. - 9781467319058 ; , s. 335-343
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Conference paper (peer-reviewed)abstract
- Opportunistic routing is widely known to have substantially better performance than traditional unicast routing in wireless networks with lossy links. However, wireless sensor networks are heavily duty-cycled, i.e. they frequently enter deep sleep states to ensure long network life-time. This renders existing opportunistic routing schemes impractical, as they assume that nodes are always awake and can overhear other transmissions. In this paper, we introduce a novel opportunistic routing metric that takes duty cycling into account. By analytical performance modeling and simulations, we show that our routing scheme results in significantly reduced delay and improved energy efficiency compared to traditional unicast routing. The method is based on a new metric, EDC, that reflects the expected number of duty cycled wakeups that are required to successfully deliver a packet from source to destination. We devise distributed algorithms that find the EDC-optimal forwarding, i.e. the optimal subset of neighbors that each node should permit to forward its packets. We compare the performance of the new routing with ETX-optimal single path routing in both simulations and testbed-based experiments.
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| 5. |
- Ghadimi, Euhanna, et al.
(author)
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The ADMM algorithm for distributed averaging : convergence rates and optimal parameter selection
- 2014
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In: CONFERENCE RECORD OF THE 2014 FORTY-EIGHTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS. - : IEEE conference proceedings. ; , s. 783-787
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Conference paper (peer-reviewed)abstract
- We derive the optimal step-size and overrelaxationparameter that minimizes the convergence time oftwo ADMM-based algorithms for distributed averaging. Ourstudy shows that the convergence times for given step-size andover-relaxation parameters depend on the spectral propertiesof the normalized Laplacian of the underlying communicationgraph. Motivated by this, we optimize the edge-weights of thecommunication graph to improve the convergence speed evenfurther. The performance of the ADMM algorithms with ourparameter selection are compared with alternatives from theliterature in extensive numerical simulations on random graphs.
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| 6. |
- Gonga, António, et al.
(author)
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Revisiting multi-channel communication to mitigate interference and link dynamics in wireless sensor networks
- 2012
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In: Proceedings - IEEE International Conference on Distributed Computing in Sensor Systems, DCOSS 2012. - : IEEE Computer Society. - 9780769547077 ; , s. 186-193
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Conference paper (peer-reviewed)abstract
- Multichannel communication has been proposed as alternative to adaptive (single-channel) routing protocols for mitigating the impact of interference and link dynamics in wireless sensor networks. While several studies have advocated features of both techniques (not without running up against contradicting arguments) a comprehensive study that aligns these results is still lacking. This paper aims at filling this gap. We present an experimental test bed setup used to perform extensive measurements for both single-channel and multichannel communication. We first analyze single-channel and multichannel communication over a single-hop in terms of packet reception ratio, maximum burst loss, temporal correlation of losses, and loss correlations across channels. Results show that multichannel communication with channel hopping significantly reduces link burstiness and packet loss correlation. For multi-hop networks, multi-channel communication and adaptive routing show similar end-to-end reliability in dense topologies, while multichannel communication can outperform adaptive routing in sparse networks with bursty links.
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| 7. |
- António, Gonga, et al.
(author)
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Multi-channel communication vs. adaptive routing for reliable communication in WSNs
- 2012
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In: IPSN'12 - ACM/IEEE Proceedings of the 11th International Conference on Information Processing in Sensor Networks, (Beijing;16 - 20 April 2012). - New York, NY, USA : ACM. - 9781450312271 ; , s. 125-126
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Conference paper (peer-reviewed)abstract
- Interference and link dynamics constitute great concerns for stability and performance of protocols in WSNs. In this paper we evaluate the impact of channel hopping and adaptive routing on delay and reliability focusing on delay critical applications.
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| 8. |
- Feyzmahdavian, Hamid Reza, et al.
(author)
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Contractive interference functions and rates of convergence of distributed power control laws
- 2012
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In: IEEE International Conference on Communications (ICC), Ottawa, Canada.. - : IEEE. - 9781457720512 ; , s. 4395-4399
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Conference paper (peer-reviewed)abstract
- The standard interference functions introduced by Yates have been very influential on the analysis and design of distributed power control laws. While powerful and versatile, the framework has some drawbacks: the existence of fixed-points has to be established separately, and no guarantees are given on the rate of convergence of the iterates. This paper introduces contractive interference functions, a slight reformulation of the standard interference functions that guarantees existence and uniqueness of fixed-points and geometric convergence rates. We show that many power control laws from the literature are contractive and derive, sometimes for the first time, convergence rate estimates for these algorithms. Finally, we show that although standard interference functions are not contractive, they are paracontractions with respect to a certain metric space. Extensions to two-sided scalable interference functions are also discussed.
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| 9. |
- Aytekin, Arda, 1986-, et al.
(author)
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Asynchronous incremental block-coordinate descent
- 2014
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In: 52nd Annual Allerton Conference on Communication, Control, and Computing (Allerton). - : IEEE conference proceedings. ; , s. 19-24
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Conference paper (peer-reviewed)abstract
- This paper studies a flexible algorithm for minimizing a sum of component functions, each of which depends on a large number of decision variables. Such formulations appear naturally in “big data” applications, where each function describes the loss estimated using the data available at a specific machine, and the number of features under consideration is huge. In our algorithm, a coordinator updates a global iterate based on delayed partial gradients of the individual objective functions with respect to blocks of coordinates. Delayed incremental gradient and delayed coordinate descent algorithms are obtained as special cases. Under the assumption of strong convexity and block coordinate-wise Lipschitz continuous partial gradients, we show that the algorithm converges linearly to a ball around the optimal value. Contrary to related proposals in the literature, our algorithm is delay-insensitive: it converges for any bounded information delay, and its step-size parameter can be chosen independently of the maximum delay bound.
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| 10. |
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