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| 2. |
- Afanasov, Mikhail, et al.
(författare)
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Programming Support for Time-sensitive Adaptation in Cyberphysical Systems
- 2018
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Ingår i: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 14:4, s. 27-32
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Tidskriftsartikel (refereegranskat)abstract
- Cyberphysical systems (CPS) integrate embedded sensors,actuators, and computing elements for controlling physicalprocesses. Due to the intimate interactions with thesurrounding environment, CPS software must continuouslyadapt to changing conditions. Enacting adaptation decisionsis often subject to strict time requirements to ensure controlstability, while CPS software must operate within the tightresource constraints that characterize CPS platforms. Developersare typically left without dedicated programmingsupport to cope with these aspects. This results in either toneglect functional or timing issues that may potentially ariseor to invest significant efforts to implement hand-crafted solutions.We provide programming constructs that allow developersto simplify the specification of adaptive processingand to rely on well-defined time semantics. Our evaluationshows that using these constructs simplifies implementationswhile reducing developers’ effort, at the price of a modestmemory and processing overhead.
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| 3. |
- Afanasov, Mikhail, et al.
(författare)
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Software Adaptation in Wireless Sensor Networks
- 2018
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Ingår i: ACM Transactions on Autonomous and Adaptive Systems. - : Association for Computing Machinery (ACM). - 1556-4665 .- 1556-4703. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- We present design concepts, programming constructs, and automatic verification techniques to support the development of adaptive Wireless Sensor Network (WSN) software. WSNs operate at the interface between the physical world and the computing machine and are hence exposed to unpredictable environment dynamics. WSN software must adapt to these dynamics to maintain dependable and efficient operation. However, developers are left without proper support to develop adaptive functionality in WSN software. Our work fills this gap with three key contributions: (i) design concepts help developers organize the necessary adaptive functionality and understand their relations, (ii) dedicated programming constructs simplify the implementations, (iii) custom verification techniques allow developers to check the correctness of their design before deployment. We implement dedicated tool support to tie the three contributions, facilitating their practical application. Our evaluation considers representative WSN applications to analyze code metrics, synthetic simulations, and cycle-accurate emulation of popular WSN platforms. The results indicate that our work is effective in simplifying the development of adaptive WSN software; for example, implementations are provably easier to test and to maintain, the run-time overhead of our dedicated programming constructs is negligible, and our verification techniques return results in a matter of seconds.
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| 4. |
- Asad, H. A., et al.
(författare)
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On Securing Persistent State in Intermittent Computing
- 2020
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Ingår i: ENSsys 2020 - Proceedings of the 8th International Workshop on Energy Harvesting and Energy-Neutral Sensing Systems. - New York, NY, USA : Association for Computing Machinery, Inc. ; , s. 8-14, s. 8-14, s. 8-14
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Konferensbidrag (refereegranskat)abstract
- We present the experimental evaluation of different security mechanisms applied to persistent state in intermittent computing. Whenever executions become intermittent because of energy scarcity, systems employ persistent state on non-volatile memories (NVMs) to ensure forward progress of applications. Persistent state spans operating system and network stack, as well as applications. While a device is off recharging energy buffers, persistent state on NVMs may be subject to security threats such as stealing sensitive information or tampering with configuration data, which may ultimately corrupt the device state and render the system unusable. Based on modern platforms of the Cortex M*series, we experimentally investigate the impact on typical intermittent computing workloads of different means to protect persistent state, including software and hardware implementations of staple encryption algorithms and the use of ARM TrustZone protection mechanisms. Our results indicate that i) software implementations bear a significant overhead in energy and time, sometimes harming forward progress, but also retaining the advantage of modularity and easier updates; ii) hardware implementations offer much lower overhead compared to their software counterparts, but require a deeper understanding of their internals to gauge their applicability in given application scenarios; and iii) TrustZone shows almost negligible overhead, yet it requires a different memory management and is only effective as long as attackers cannot directly access the NVMs.
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| 5. |
- Azzarà, Andrea, et al.
(författare)
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Virtual Resources for the Internet of Things
- 2015. - 12
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Ingår i: 2015 IEEE 2nd World Forum on Internet of Things (WF-IoT). - 9781509003662 ; , s. 245-250
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Konferensbidrag (refereegranskat)abstract
- We present Virtual Resources: a software architecture to resolve the tension between effective development and efficient operation of Internet of Things (IoT) applications. Emerging IoT architectures exhibit recurring traits: resource-limited sensors and actuators with RESTful interfaces at one end; full-fledged Cloud-hosted applications at the opposite end. The application logic resides entirely at the latter, creating performance issues such as excessive energy consumption and high latencies. To ameliorate these, Virtual Resources allows developers to push a slice of the application logic to intermediate IoT devices, creating a continuum between physical resources and Cloud-hosted applications. With Virtual Resources, for example, developers can push processing of sensed data to IoT devices close to the physical sensors, reducing the data to transmit and thus saving energy. We describe the key concepts of Virtual Resources and their realization in a CoAP prototype atop resource-constrained devices. Experimental results from cycle-accurate emulation indicate that Virtual Resources enable better performance than Cloud-centric architectures, while retaining the RESTful interaction pattern. For example, energy consumption in representative scenarios improves up to 40% and control loop latencies reduce up to 60%.
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| 6. |
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| 7. |
- Baccour, Nouha, et al.
(författare)
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Radio Link Quality Estimation in Wireless Sensor Networks: a Survey
- 2012. - 13
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Ingår i: ACM Transactions on Sensor Networks. - : Association for Computing Machinery (ACM). - 1550-4859 .- 1550-4867. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Radio link quality estimation inWireless SensorNetworks (WSNs) has a fundamental impact on the network performance and also affects the design of higher-layer protocols. Therefore, for about a decade, it has been attracting a vast array of research works. Reported works on link quality estimation are typically based on different assumptions, consider different scenarios, and provide radically different (and sometimes contradictory) results. This article provides a comprehensive survey on related literature, covering the characteristics of low-power links, the fundamental concepts of link quality estimation inWSNs, a taxonomy of existing link quality estimators, and their performance analysis. To the best of our knowledge, this is the first survey tackling in detail link quality estimation in WSNs. We believe our efforts will serve as a reference to orient researchers and system designers in this area.
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| 8. |
- Baresi, Luciano, et al.
(författare)
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Building Software for the Internet of Things
- 2015. - 9
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Ingår i: IEEE Internet Computing. - 1089-7801 .- 1941-0131. ; 19:2, s. 6-8
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Tidskriftsartikel (refereegranskat)abstract
- The guest editors present a special issue on building software for the Internet of Things (IoT).
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| 9. |
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| 10. |
- Boano, Carlo Alberto, et al.
(författare)
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Making Sensornet MAC Protocols Robust Against Interference
- 2010. - 10
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Konferensbidrag (refereegranskat)abstract
- Radio interference may lead to packet losses, thus negatively affecting the performance of sensornet applications. In this paper, we experimentally assess the impact of external interference on state-of-the-art sensornet MAC protocols. Our experiments illustrate that specific features of existing protocols, e.g., hand-shaking schemes preceding the actual data transmission, play a critical role in this setting. We leverage these results by identifying mechanisms to improve the robustness of existing MAC protocols under interference. These mechanisms include the use of multiple hand-shaking attempts coupled with packet trains and suitable congestion backoff schemes to better tolerate interference. We embed these mechanisms within an existing X-MAC implementation and show that they considerably improve the packet delivery rate while keeping the power consumption at a moderate level.
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