| 1. |
- She, Huimin, 1982-
(författare)
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Network-Calculus-based Performance Analysis for Wireless Sensor Networks
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recently, wireless sensor network (WSN) has become a promising technologywith a wide range of applications such as supply chain monitoringand environment surveillance. It is typically composed of multiple tiny devicesequipped with limited sensing, computing and wireless communicationcapabilities. Design of such networks presents several technique challengeswhile dealing with various requirements and diverse constraints. Performanceanalysis techniques are required to provide insight on design parametersand system behaviors. Based on network calculus, we present a deterministic analysis methodfor evaluating the worst-case delay and buffer cost of sensor networks. Tothis end, three general traffic flow operators are proposed and their delayand buffer bounds are derived. These operators can be used in combinationto model any complex traffic flowing scenarios. Furthermore, the methodintegrates a variable duty cycle to allow the sensor nodes to operate at lowrates thus saving power. In an attempt to balance traffic load and improveresource utilization and performance, traffic splitting mechanisms areintroduced for mesh sensor networks. Based on network calculus, the delayand buffer bounds are derived in non-splitting and splitting scenarios.In addition, analysis of traffic splitting mechanisms are extended to sensornetworks with general topologies. To provide reliable data delivery in sensornetworks, retransmission has been adopted as one of the most popularschemes. We propose an analytical method to evaluate the maximum datatransmission delay and energy consumption of two types of retransmissionschemes: hop-by-hop retransmission and end-to-end retransmission. We perform a case study of using sensor networks for a fresh food trackingsystem. Several experiments are carried out in the Omnet++ simulationenvironment. In order to validate the tightness of the two bounds obtainedby the analysis method, the simulation results and analytical results arecompared in the chain and mesh scenarios with various input traffic loads.From the results, we show that the analytic bounds are correct and tight.Therefore, network calculus is useful and accurate for performance analysisof wireless sensor network.
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| 2. |
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| 3. |
- Liu, Ming, et al.
(författare)
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System-on-an-FPGA Design for Real-time Particle Track Recognition and Reconstruction in Physics Experiments
- 2008
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Ingår i: 11TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN - ARCHITECTURES, METHODS AND TOOLS. - LOS ALAMITOS : IEEE COMPUTER SOC. ; , s. 599-605
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Konferensbidrag (refereegranskat)abstract
- In particle physics experiments, the momenta of charged particles are studied by observing their deflection in a magnetic field. Dedicated detectors measure the particle tracks and complex algorithms are required for track recognition and reconstruction. This CPU-intensive task is usually implemented as off-line software running on PC clusters. In this paper we present a system-on-chip design for the track recognition and reconstruction based on modern FPGA technologies. The basic principle of the algorithm is polled from software into the FPGA fabric. The fundamental architecture of the tracking processor is described in detail. Working as processing engines in compute nodes, the tracking processor contributes to recognize potential track candidates in real-time and promotes the selection efficiency of the data acquisition and trigger system. Our design study shows that the tracking module can be integrated in a single Xilinx Virtex-4 FX60 FPGA. The processing capability of the design is about 16.7K sub-events per second per module with our experimental setup, which achieves 20 times speedup compared to the software implementation.
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| 4. |
- She, Huimin, et al.
(författare)
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Analytical Evaluation of Retransmission Schemes in Wireless Sensor Networks
- 2009
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Ingår i: 2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE. - 9781424425167 ; , s. 38-42
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Konferensbidrag (refereegranskat)abstract
- Retransmission has been adopted as one of the most popular schemes for improving transmission reliability in wireless sensor networks. Many previous works have been done on reliable transmission issues in experimental ways, however, there still lack of analytical techniques to evaluate these solutions. Based on the traffic model, service model and energy model, we propose an analytical method to analyze the delay and energy metrics of two categories of retransmission schemes: hop-by-hop retransmission (HBH) and end-to-end retransmission (ETE). With the experiment results, the maximum packet transfer delay and energy efficiency of these two scheme are compared in several scenarios. Moreover, the analytical results of transfer delay are validated through simulations. Our experiments demonstrate that HBH has less energy consumption at the cost of lager transfer delay compared with ETE. With the same target success probability, ETE is superior on the delay metric for low bit-error-rate (BER) cases, while HBH is superior for high BER cases.
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| 5. |
- Haghbayan, M. -H, et al.
(författare)
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MapPro : Proactive runtime mapping for dynamic workloads by quantifying ripple effect of applications on networks-on-chip
- 2015
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Ingår i: Proceedings - 2015 9th IEEE/ACM International Symposium on Networks-on-Chip, NOCS 2015. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450333962
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Konferensbidrag (refereegranskat)abstract
- Increasing dynamic workloads running on NoC-based many-core systems necessitates efficient runtime mapping strategies. With an unpredictable nature of application profiles, selecting a rational region to map an incoming application is an NP-hard problem in view of minimizing congestion and maximizing performance. In this paper, we propose a proactive region selection strategy which prioritizes nodes that offer lower congestion and dispersion. Our proposed strategy, MapPro, quantitatively represents the propagated impact of spatial availability and dispersion on the network with every new mapped application. This allows us to identify a suitable region to accommodate an incoming application that results in minimal congestion and dispersion. We cluster the network into squares of different radii to suit applications of different sizes and proactively select a suitable square for a new application, eliminating the overhead caused with typical reactive mapping approaches. We evaluated our proposed strategy over different traffic patterns and observed gains of up to 41% in energy efficiency, 28% in congestion and 21% dispersion when compared to the state-of-the-art region selection methods. Copyright 2015 ACM.
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| 6. |
- Rahmani, Amir-Mohammad, et al.
(författare)
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Dynamic Power Management for Many-Core Platforms in the Dark Silicon Era : A Multi-Objective Control Approach
- 2015
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Ingår i: Low Power Electronics and Design (ISLPED), 2015 IEEE/ACM International Symposium on. - : IEEE conference proceedings. - 9781467380089 ; , s. 219-224
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Konferensbidrag (refereegranskat)abstract
- Power management of NoC-based many-core systems with runtime application mapping becomes more challenging in the dark silicon era. It necessitates a multi-objective control approach to consider an upper limit on total power consumption, dynamic behaviour of workloads, processing elements utilization, per-core power consumption, and load on network-on-chip. In this paper, we propose a multi-objective dynamic power management method that simultaneously considers all of these parameters. Fine-grained voltage and frequency scaling, including near-threshold operation, and per-core power gating are utilized to optimize the performance. In addition, a disturbance rejecter is designed that proactively scales down activity in running applications when a new application commences execution, to prevent sharp power budget violations. Simulations of dynamic workloads and mixed time-critical application profiles show that our method is effective in honoring the power budget while considerably boosting the system throughput and reducing power budget violation, compared to the state-of-the-art power management policies.
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| 7. |
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| 8. |
- Chen, Xiaowen, et al.
(författare)
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Reducing Virtual-to-Physical address translation overhead in Distributed Shared Memory based multi-core Network-on-Chips according to data property
- 2013
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Ingår i: Computers & electrical engineering. - : Elsevier BV. - 0045-7906 .- 1879-0755. ; 39:2, s. 596-612
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Tidskriftsartikel (refereegranskat)abstract
- In Network-on-Chip (NoC) based multi-core platforms, Distributed Shared Memory (DSM) preferably uses virtual addressing in order to hide the physical locations of the memories. However, this incurs performance penalty due to the Virtual-to-Physical (V2P) address translation overhead for all memory accesses. Based on the data property which can be either private or shared, this paper proposes a hybrid DSM which partitions a local memory into a private and a shared part. The private part is accessed directly using physical addressing and the shared part using virtual addressing. In particular, the partitioning boundary can be configured statically at design time and dynamically at runtime. The dynamic configuration further removes the V2P address translation overhead for those data with changeable property when they become private at runtime. In the experiments with three applications (matrix multiplication, 2D FFT, and H.264/AVC encoding), compared with the conventional DSM, our techniques show performance improvement up to 37.89%.
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| 9. |
- Raudvere, Tarvo, et al.
(författare)
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The ForSyDe semantics
- 2002
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Ingår i: Proceedings of Swedish System-on-Chip Conference.
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Konferensbidrag (refereegranskat)
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| 10. |
- She, Huimin, et al.
(författare)
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Traffic splitting with network calculus for mesh sensor networks
- 2007
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Ingår i: Proceedings of Future Generation Communication and Networking, FGCN 2007. - : IEEE Computer Society. - 9780769530482 ; , s. 371-376
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Konferensbidrag (refereegranskat)abstract
- In many applications of sensor networks, it is essential to ensure that messages are transmitted to their destinations as early as possible and the buffer size of each sensor node is as small as possible. In this paper, we firstly propose a mesh sensor network system model. Based on this system model, the expressions for deriving the delay bound and buffer requirement bound are presented using network calculus. In order to balance traffic load and improve resource utilization, three traffic splitting mechanisms are proposed The numerical results show that the delay bound and buffer requirement bound are lowered while applying those traffic splitting mechanisms. And thus the performance of the whole sensor network is improved.
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