| 1. |
- Pérez-Penichet, Carlos, et al.
(författare)
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Poster abstract : Augmenting WSNs with interoperable 802.15.4 sensor tags
- 2017
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Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- The sensing capabilities of most sensor networks are fixed at the time of deployment. Adding new sensing capabilities to such networks is a costly and cumbersome process. We present Passive Sensor Tags, battery-free sensing devices that could be used to extend the sensing capabilities of an existing network. Sensor tags feature our new 802.15.4 receiver design which is suitable for micro-power operation, making battery-free tags possible. Because our tags can both transmit and receive 802.15.4 frames there is no need for any modification to the deployed hardware. We present preliminary measurements of transmission and reception range.
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| 2. |
- Al Nahas, Beshr, 1985, et al.
(författare)
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Low-power listening goes multi-channel
- 2014
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Ingår i: Proceedings - IEEE International Conference on Distributed Computing in Sensor Systems, DCOSS 2014. ; , s. 2-9
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Konferensbidrag (refereegranskat)abstract
- Exploiting multiple radio channels for communication has been long known as a practical way to mitigate interference in wireless settings. In Wireless Sensor Networks, however, multi-channel solutions have not reached their full potential: the MAC layers included in TinyOS or the Contiki OS for example are mostly single-channel. The literature offers a number of interesting solutions, but experimental results were often too few to build confidence. We propose a practical extension of low-power listening, MiCMAC, that performs channel hopping, operates in a distributed way, and is independent of upper layers of the protocol stack. The above properties make it easy to deploy in a variety of scenarios, without any extra configuration/scheduling/channel selection hassle. We implement our solution in Contiki and evaluate it in a 97-node~testbed while running a complete, out-of-the-box low-power IPv6 communication stack (UDP/RPL/6LoWPAN). Our experimental results demonstrate increased resilience to emulated WiFi interference (e.g., data yield kept above 90% when Contiki MAC drops in the 40% range). In noiseless environments, MiCMAC keeps the overhead low in comparison to Contiki MAC, achieving performance as high as 99% data yield along with sub-percent duty cycle and sub-second latency for a 1-minute inter-packet interval data collection. © 2014 IEEE.
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| 3. |
- Shen, Qianyao, et al.
(författare)
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CNN-Based Estimation of Water Depth from Multispectral Drone Imagery for Mosquito Control
- 2023
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Ingår i: 2023 IEEE International Conference on Image Processing, ICIP 2023 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728198354 - 9781728198361 ; , s. 3250-3254
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Konferensbidrag (refereegranskat)abstract
- We present a machine learning approach that uses a custom Convolutional Neural Network (CNN) for estimating the depth of water pools from multispectral drone imagery. Using drones to obtain this information offers a cheaper, timely, and more accurate solution compared to alternative methods, such as manual inspection. This information, in turn, represents an asset to identify potential breeding sites of mosquito larvae, which grow only in shallow water pools. As a significant part of the world's population is affected by mosquito-borne viral infections, including Dengue and Zika, identifying mosquito breeding sites is key to control their spread. Experiments with 5-band drone imagery show that our CNN-based approach is able to measure shallow water depths accurately up to a root mean square error of less than 0.5 cm, outperforming state-of-the-art Random Forest methods and empirical approaches.
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| 4. |
- Piumwardane, Dilushi, et al.
(författare)
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Unlocking the Potential of Low-cost High-resolution Sensing with Analog Backscatter
- 2024
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Ingår i: 2024 IEEE International Conference on RFID (RFID). - : Institute of Electrical and Electronics Engineers (IEEE). - 9798350373592 - 9798350373608 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Analog backscatter enables sensing and communication while consuming significantly lower power than digital backscatter. An analog backscatter tag maps sensor readings directly to backscatter transmissions avoiding power hungry blocks such as ADCs. The sensor value variations are backscattered atop a carrier as changes in frequency and amplitude. Frequency variations are commonly used in backscatter, to avoid the strong self-interference from the carrier. The range of the sensor output linearly maps to the range of base-band frequency variation. Hence a sensor with a wider output range requires a larger base-band frequency range to encode sensor data. This increases the tag oscillator's switching frequency and hence the tag's power consumption. We propose to use higher order harmonic frequencies which allows us to reduce the tag switching frequency and read sensor data even when the carrier masks the fundamental frequency. Our system design lowers the cost and power consumption of the analog backscatter system making it suitable for mobile-based sensing applications. We present experimental results demonstrating the viability of our approach and implement a complete system that includes a lowcost radio receiver. Using a carrier with 0 dBm power, we detect the 15th harmonic up to three meters resulting in 15 times more frequency resolution than the fundamental while reducing the tag oscillator's power consumption by more than 43%. The 7th harmonic is visible up to 18 meters. Increasing the carrier power enables the detection of additional harmonic frequencies.
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| 5. |
- He, Zhitao
(författare)
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Enabling Scalable Security in Internet of Things
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The popular notion of Internet of Things (IoT) implies two salient features: 1. a diversity of small things, i.e., constrained devices; 2. their seamless integration with the Internet. Pioneering work in Wireless Sensor Networks (WSNs) have laid a solid technological foundation for autonomous, low power wireless communication among battery-powered, microcontroller-based devices. On the other hand, as devices are being connected to the Internet in large numbers, industry experts and regulators have associated IoT with enormous security risk. Sensitive personal information, highly complex business workflows, and critical infrastructure for public safety are at stake. In this dissertation, we first explore the scalability of IoT. Approaching from the particular angle of radio interference, we study unstable and faulty network behavior when links between low power radios are disrupted. Our low cost and practical interference generation tools fill a gap between protocol design and test. We then underline the threat of novel attacks at the physical layer, which lead to denial of service and battery draining of low power radios. Launched from low cost hardware, the attacks we devise are power-efficient and hard to detect; and they reach longer ranges than jamming. Finally, we take a step closer to realization of secure and large-scale IoT deployment by enabling certificate enrollment, a key component in a public key infrastructure, for small devices. We show that automated enrollment of device certificates becomes feasible when a memory and power efficient IoT protocol stack is leveraged. Spanning between the physical layer and the application layer, our work has enriched the knowledge domain of IoT and advanced the technological frontier of scalable and secure IoT deployment.
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| 6. |
- Krentz, Konrad-Felix, et al.
(författare)
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Multi-Armed Bandit-based Channel Hopping : Implementation on Embedded Devices
- 2022
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Ingår i: Machine Learning for Networking. - Cham : Springer. - 9783030989781 - 9783030989774 ; , s. 29-47
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Konferensbidrag (refereegranskat)abstract
- Simulations have shown multi-armed bandit (MAB) algorithms to be suitable for optimizing channel hopping in IEEE 802.15.4 networks. Thus far, however, there appears to be no practical implementation of this approach, presumably because typical IEEE 802.15.4 nodes lack both floating-point units (FPUs) and big amounts of random access memory (RAM). In this paper, we propose fixed-point arithmetic and implementation shortcuts to circumvent these constraints. We focus on two specific multi-armed bandit (MAB) algorithms, namely sliding-window upper confidence bound (SW-UCB) and its predecessor discounted UCB (D-UCB). SW-UCB is particularly promising since it requires only tractable fixed-point arithmetic, while yielding high packet delivery ratios (PDRs) according to prior work. D-UCB, on the other hand, additionally opens up an implementation shortcut that saves RAM. Our implementations of SW-UCB and D-UCB are integrated into Contiki-NG, yet can also be used out-of-tree in a simulation environment. We show our SW-UCB (resp. D-UCB) implementation to attain PDRs of 98.6% (resp. 99.2%) under appropriate parameter settings in the context of intra-body communication. Also, we demonstrate D-UCB to incur a moderate RAM, program memory, and processing overhead on CC2538 SoCs, whereas we find SW-UCB too RAM-consuming for these chips. Finally, using Monte Carlo simulations, we show our SW-UCB and D-UCB implementations to perform equally well as floating-point counterparts.
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| 7. |
- Krentz, Konrad-Felix, et al.
(författare)
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Reducing Trust Assumptions with OSCORE, RISC-V, and Layer 2 One-Time Passwords
- 2023
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Ingår i: <em>Lecture Notes in Computer Science </em>Volume 13877 Pages 389 - 405 2023. - Cham : Springer Science and Business Media Deutschland GmbH. - 9783031301216 - 9783031301223 ; , s. 389-405
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Konferensbidrag (refereegranskat)abstract
- In the Internet of things (IoT), traffic often goes via middleboxes, such as brokers or virtual private network (VPN) gateways, thereby increasing the trusted computing base (TCB) of IoT applications considerably. A remedy is offered by the application layer security protocol Object Security for Constrained RESTful Environments (OSCORE). It allows for basic middlebox functions without breaking end-to-end security. With OSCORE, however, traffic is routed to IoT devices largely unfiltered. This opens up avenues for remote denial-of-sleep attacks where a remote attacker injects OSCORE messages so as to cause IoT devices to consume more energy. The state-of-the-art defense is to let a trusted middlebox perform authenticity, freshness, and per-client rate limitation checks before forwarding OSCORE messages to IoT devices, but this solution inflates the TCB and hence negates the idea behind OSCORE. In this paper, we suggest filtering OSCORE messages in a RISC-V-based trusted execution environment (TEE) running on a middlebox that remains widely untrusted. To realize this approach, we also put forward the tiny remote attestation protocol (TRAP), as well as a Layer 2 integration that prevents attackers from bypassing our TEE. Experimental results show our remote denial-of-sleep defense to be lightweight enough for low-end IoT devices and to keep the TCB small. © 2023, The Author(s)
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| 8. |
- N. Sathi, Vipin, et al.
(författare)
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A PUF-Based Indirect Authentication and Key Establishment Protocol for Wearable Devices
- 2023
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Ingår i: IEEE International Conference on Communications (ICC). - : Institute of Electrical and Electronics Engineers Inc.. - 9781538674628 - 9781538674635 ; , s. 615-621
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Konferensbidrag (refereegranskat)abstract
- Microwave communication through the fat tissue in the human body enables a new channel for wearable devices to communicate with each other. The wearable devices can communicate to the external world through a powerful device in their network called central control unit (CU); for example, a smartphone. Some wearable devices may be out of the range of the CU temporarily due to body movements or permanently due to low signal strength, in a fat channel communication network. Such devices can connect to the CU with the help of their neighbor device in the same network. In this paper, we propose a protocol to ensure secure indirect authentication and key establishment between the out-of-range device and the CU in a fat channel communication network, via an untrusted intermediate device in the network. The proposed protocol is lightweight and resistant to denial-of-sleep attacks on the intermediate device. We analyze the security and the computation overhead of the proposed protocol.
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| 9. |
- Pérez-Penichet, Carlos, et al.
(författare)
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On limits of constructive interference in backscatter systems
- 2017
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Ingår i: GIoTS 2017 - Global Internet of Things Summit, Proceedings. - : IEEE. - 9781509058730
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Konferensbidrag (refereegranskat)abstract
- Backscatter communication reduces the energy consumption of resource-constrained sensors and actuators by several orders of magnitude as it avoids the resource-consuming need to generate a radio wave. Many backscatter systems and applications suffer from low communication range. By exploiting the collective power of several tags that transmit the same data simultaneously, constructive interference may help to remedy this problem and increase the communication range. When several tags backscatter the same signal simultaneously it is not necessarily true that constructive interference occurs. As our theoretical results and previous work indicate the interference might also be destructive. Our experimental results on real hardware suggest that exploiting constructive interference to increase the communication range requires careful coordination which is difficult in decentralized settings.
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| 10. |
- Pérez-Penichet, Carlos
(författare)
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Seamless Integration of Battery-Free Communications in Commodity Wireless Networks
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ubiquitous sensing applications have countless potential benefits to society. However, batteries have long been an obstacle to their full development. Harvesting energy from the environment is a promising alternative to battery power, but traditional radio transceivers consume too much for most harvesters. This work is motivated by backscatter communications, a technique that reduces the energy that devices spend exchanging data by up to three orders of magnitude relative to regular radios. This reduction enables sensing devices that operate indefinitely without having to replace batteries; instead they leverage energy harvesting. My goal is to enable the seamless integration of battery-free devices with widespread low-power commodity networks such as Bluetooth or ZigBee/IEEE 802.15.4. Making this integration seamless is critical for the broad adoption of the new class of devices.At a high level, my dissertation outlines a series of challenges to the seamless integration of the new devices with regular low-power networks. We then propose ways to address these challenges, and demonstrate how we could integrate ultra-low-power battery-free devices with regular networks, while avoiding hardware modifications and minimizing any disruption that the addition may cause to existing and co-located communication devices.This work advances the state of the art by: First, demonstrating how to augment an existing sensor network with new sensors without any hardware modification to the pre-existing hardware. The existing network provides the unmodulated carrier that the battery-free nodes need to communicate. Second, we demonstrate a radio receiver that, if implemented in silicon, can directly receive low-power commodity wireless signals when assisted by an unmodulated carrier, and with a power consumption of a few hundred microwatts. The receiver makes battery-free devices directly compatible with regular networks. We introduce simulation models and a first-of-its-kind tool to simulate battery-free communications that integrate with regular networks. Finally, we demonstrate how to efficiently provide unmodulated carrier support for battery-free devices in the previous scenarios without unnecessarily spending energy and spectrum and without undue disturbance to co-located devices.
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