2017
[12]
M. Baddeley, R. Nejabati, G. Oikonomou, S. Gormus, M. Sooriyabandara, D. Simeonidou, "Isolating SDN control traffic with layer-2 slicing in 6TiSCH industrial IoT networks", in Proc. IEEE NFV-SDN, pp. 247-251, 2017
@INPROCEEDINGS{Baddeley-2018-nfv-sdn, author = {Michael Baddeley and Reza Nejabati and George Oikonomou and Sedat Gormus and Mahesh Sooriyabandara and Dimitra Simeonidou}, booktitle = {Proc. IEEE NFV-SDN}, title = {Isolating SDN control traffic with layer-2 slicing in 6TiSCH industrial IoT networks}, year = {2017}, month = nov, pages = {247-251}, publisher = {IEEE}, doi = {10.1109/NFV-SDN.2017.8169876}, gsid = {3676551668416552782}, oa-url = {https://research-information.bristol.ac.uk/en/publications/isolating-sdn-control-traffic-with-layer2-slicing-in-6tisch-industrial-iot-networks(9873c63c-8204-4f73-8c80-68fa3eedd9e9).html}, abstract = {Recent standardization efforts in IEEE 802.15.4-2015 Time Scheduled Channel Hopping (TSCH) and the IETF 6TiSCH Working Group (WG), aim to provide deterministic communications and efficient allocation of resources across constrained Internet of Things (IoT) networks, particularly in Industrial IoT (IIoT) scenarios. Within 6TiSCH, Software Defined Networking (SDN) has been identified as means of providing centralized control in a number of key situations. However, implementing a centralized SDN architecture in a Low Power and Lossy Network (LLN) faces considerable challenges: not only is controller traffic subject to jitter due to unreliable links and network contention, but the overhead generated by SDN can severely affect the performance of other traffic. This paper proposes using 6TiSCH tracks, a Layer-2 slicing mechanism for creating dedicated forwarding paths across TSCH networks, in order to isolate the SDN control overhead. Not only does this prevent control traffic from affecting the performance of other data flows, but the properties of 6TiSCH tracks allows deterministic, low-latency SDN controller communication. Using our own lightweight SDN implementation for Contiki OS, we firstly demonstrate the effect of SDN control traffic on application data flows across a 6TiSCH network. We then show that by slicing the network through the allocation of dedicated resources along a SDN control path, tracks provide an effective means of mitigating the cost of SDN control overhead in IEEE 802.15.4-2015 TSCH networks.}, }
Recent standardization efforts in IEEE 802.15.4-2015 Time Scheduled Channel Hopping (TSCH) and the IETF 6TiSCH Working Group (WG), aim to provide deterministic communications and efficient allocation of resources across constrained Internet of Things (IoT) networks, particularly in Industrial IoT (IIoT) scenarios. Within 6TiSCH, Software Defined Networking (SDN) has been identified as means of providing centralized control in a number of key situations. However, implementing a centralized SDN architecture in a Low Power and Lossy Network (LLN) faces considerable challenges: not only is controller traffic subject to jitter due to unreliable links and network contention, but the overhead generated by SDN can severely affect the performance of other traffic. This paper proposes using 6TiSCH tracks, a Layer-2 slicing mechanism for creating dedicated forwarding paths across TSCH networks, in order to isolate the SDN control overhead. Not only does this prevent control traffic from affecting the performance of other data flows, but the properties of 6TiSCH tracks allows deterministic, low-latency SDN controller communication. Using our own lightweight SDN implementation for Contiki OS, we firstly demonstrate the effect of SDN control traffic on application data flows across a 6TiSCH network. We then show that by slicing the network through the allocation of dedicated resources along a SDN control path, tracks provide an effective means of mitigating the cost of SDN control overhead in IEEE 802.15.4-2015 TSCH networks.
[11]
S. Duquennoy, A. Elsts, B. Nahas, G. Oikonomou, "TSCH and 6TiSCH for Contiki: challenges, design and evaluation", in Proc. IEEE DCOSS, pp. 11-13, 2017
@INPROCEEDINGS{Elsts-2017-dcoss-b, title = {TSCH and 6TiSCH for Contiki: challenges, design and evaluation}, author = {Simon Duquennoy and Atis Elsts and {Al Nahas}, Beshr and George Oikonomou}, year = {2017}, month = {3}, booktitle = {Proc. IEEE DCOSS}, publisher = {IEEE}, pages = {11-13}, gsid = {11516234474205003432}, doi = {10.1109/DCOSS.2017.29}, oa-url = {https://research-information.bristol.ac.uk/en/publications/tsch-and-6tisch-for-contiki(f9e8cc62-0f9a-495a-9a38-208a5d1450b9).html}, abstract = {Synchronized communication has recently emerged as a prime option for low-power critical applications. Solutions such as Glossy or Time Slotted Channel Hopping (TSCH) have demonstrated end-to-end reliability upwards of 99.99%. In this context, the IETF Working Group 6TiSCH is currently standardizing the mechanisms to use TSCH in low-power IPv6 scenarios. This paper identifies a number of challenges when it comes to implementing the 6TiSCH stack. It shows how these challenges can be addressed with practical solutions for locking, queuing, scheduling and other aspects. With this implementation as an enabler, we present an experimental validation and comparison with state-of-the-art MAC protocols. We conduct fine-grained energy profiling, showing the impact of link-layer security on packet transmission. We evaluate distributed time synchronization in a 340-node testbed, and demonstrate that tight synchronization (hundreds of microseconds) can be achieved at very low cost (0.3% duty cycle, 0.008% channel utilization). We finally compare TSCH against traditional MAC layers: low-power listening (LPL) and CSMA, in terms of reliability, latency and energy. We show that with proper scheduling, TSCH achieves by far the highest reliability, and outperforms LPL in both energy and latency.}, }
Synchronized communication has recently emerged as a prime option for low-power critical applications. Solutions such as Glossy or Time Slotted Channel Hopping (TSCH) have demonstrated end-to-end reliability upwards of 99.99%. In this context, the IETF Working Group 6TiSCH is currently standardizing the mechanisms to use TSCH in low-power IPv6 scenarios. This paper identifies a number of challenges when it comes to implementing the 6TiSCH stack. It shows how these challenges can be addressed with practical solutions for locking, queuing, scheduling and other aspects. With this implementation as an enabler, we present an experimental validation and comparison with state-of-the-art MAC protocols. We conduct fine-grained energy profiling, showing the impact of link-layer security on packet transmission. We evaluate distributed time synchronization in a 340-node testbed, and demonstrate that tight synchronization (hundreds of microseconds) can be achieved at very low cost (0.3% duty cycle, 0.008% channel utilization). We finally compare TSCH against traditional MAC layers: low-power listening (LPL) and CSMA, in terms of reliability, latency and energy. We show that with proper scheduling, TSCH achieves by far the highest reliability, and outperforms LPL in both energy and latency.
[10]
@INPROCEEDINGS{Elsts-2017-dcoss, title = {Scheduling high-rate unpredictable traffic in IEEE 802.15.4 TSCH networks}, keywords = {Time slotted channel hopping, scheduling, Internet of Things}, author = {Atis Elsts and Xenofon Fafoutis and James Pope and George Oikonomou and Robert Piechocki and Ian Craddock}, year = {2017}, month = {3}, booktitle = {Proc. IEEE DCOSS}, gsid = {11148583356626153925}, publisher = {IEEE}, pages = {3-10}, doi = {10.1109/DCOSS.2017.20}, oa-url = {https://research-information.bristol.ac.uk/en/publications/scheduling-highrate-unpredictable-traffic-in-ieee-802154-tsch-networks(74903df9-1c10-438c-8a05-7a4ccad936ac).html}, abstract = {The upcoming Internet of Things (IoT) applications include real-time human activity monitoring with wearable sensors. Compared to the traditional environmental sensing with low-power wireless nodes, these new applications generate a constant stream of a much higher rate. Nevertheless, the wearable devices remain battery powered and therefore restricted to low-power wireless standards such as IEEE 802.15.4 or Bluetooth Low Energy (BLE). Our work tackles the problem of building a reliable autonomous schedule for forwarding this kind of dynamic data in IEEE 802.15.4 TSCH networks. Due to the a priori unpredictability of these data source locations, the quality of the wireless links, and the routing topology of the forwarding network, it is wasteful to reserve the number of slots required for the worst-case scenario; under conditions of high expected datarate, it is downright impossible. The solution we propose is a hybrid approach where dedicated TSCH cells and shared TSCH slots coexist in the same schedule. We show that under realistic assumptions of wireless link diversity, adding shared slots to a TSCH schedule increases the overall packet delivery rate and the fairness of the system.}, }
The upcoming Internet of Things (IoT) applications include real-time human activity monitoring with wearable sensors. Compared to the traditional environmental sensing with low-power wireless nodes, these new applications generate a constant stream of a much higher rate. Nevertheless, the wearable devices remain battery powered and therefore restricted to low-power wireless standards such as IEEE 802.15.4 or Bluetooth Low Energy (BLE). Our work tackles the problem of building a reliable autonomous schedule for forwarding this kind of dynamic data in IEEE 802.15.4 TSCH networks. Due to the a priori unpredictability of these data source locations, the quality of the wireless links, and the routing topology of the forwarding network, it is wasteful to reserve the number of slots required for the worst-case scenario; under conditions of high expected datarate, it is downright impossible. The solution we propose is a hybrid approach where dedicated TSCH cells and shared TSCH slots coexist in the same schedule. We show that under realistic assumptions of wireless link diversity, adding shared slots to a TSCH schedule increases the overall packet delivery rate and the fairness of the system.
[9]
@INPROCEEDINGS{Elsts-2017-SenseApp, title = {Microsecond-accuracy time synchronization using the IEEE 802.15.4 TSCH Protocol}, author = {Atis Elsts and Simon Duquennoy and Xenofon Fafoutis and George Oikonomou and Robert Piechocki and Ian Craddock}, year = {2017}, month = {2}, doi = {10.1109/LCN.2016.042}, oa-url = {http://research-information.bristol.ac.uk/en/publications/microsecondaccuracy-time-synchronization-using-the-ieee-802154-tsch-protocol(2e47abe7-60e9-48a7-9f09-9fe7f4859ccb).html}, booktitle = {Proc. IEEE SenseApp}, publisher = {IEEE}, gsid = {11807852472963901506}, abstract = {Time-Slotted Channel Hopping from the IEEE 802.15.4-2015 standard requires that network nodes are tightly time-synchronized. Existing implementations of TSCH on embedded hardware are characterized by tens-of-microseconds large synchronization errors; higher synchronization accuracy would enable reduction of idle listening time on receivers, in this way decreasing the energy required to run TSCH. For some applications, it would also allow to replace dedicated time synchronization mechanisms with TSCH. We show that time synchronization errors in the existing TSCH implementations on embedded hardware are caused primarily by imprecise clock drift estimations, rather than by real unpredictable drift variance. By estimating clock drift more precisely and by applying adaptive time compensation on each node in the network, we achieve microsecond accuracy time synchronization on point-to-point links and a <2 microsecond end-to-end error in a 7-node line topology. Our solution is implemented in the Contiki operating system and tested on Texas Instruments CC2650-based nodes, equipped with common off-the-shelf hardware clock sources (20 ppm drift). Our implementation uses only standard TSCH control messages and is able to keep radio duty cycle below 1%.} }
Time-Slotted Channel Hopping from the IEEE 802.15.4-2015 standard requires that network nodes are tightly time-synchronized. Existing implementations of TSCH on embedded hardware are characterized by tens-of-microseconds large synchronization errors; higher synchronization accuracy would enable reduction of idle listening time on receivers, in this way decreasing the energy required to run TSCH. For some applications, it would also allow to replace dedicated time synchronization mechanisms with TSCH. We show that time synchronization errors in the existing TSCH implementations on embedded hardware are caused primarily by imprecise clock drift estimations, rather than by real unpredictable drift variance. By estimating clock drift more precisely and by applying adaptive time compensation on each node in the network, we achieve microsecond accuracy time synchronization on point-to-point links and a <2 microsecond end-to-end error in a 7-node line topology. Our solution is implemented in the Contiki operating system and tested on Texas Instruments CC2650-based nodes, equipped with common off-the-shelf hardware clock sources (20 ppm drift). Our implementation uses only standard TSCH control messages and is able to keep radio duty cycle below 1%.
[8]
@INPROCEEDINGS{Elsts-2017-gsiot, title = {Internet of things for smart homes: lessons learned from the SPHERE case study}, author = {Atis Elsts and George Oikonomou and Xenofon Fafoutis and Robert Piechocki}, year = {2017}, month = {3}, booktitle = {Proc. GIoTS}, publisher = {IEEE}, doi = {10.1109/GIOTS.2017.8016226}, gsid = {6103776013711544890}, oa-url = {https://research-information.bristol.ac.uk/en/publications/internet-of-things-for-smart-homes(f86c4eb4-87ec-428a-8d50-9427166d97fd).html}, abstract = {Building large-scale low-power Internet of Things (IoT) systems remains a challenge, as these systems have to meet the requirements of reliability, robustness, and energy- efficiency while running on resource-restricted microcontrollers without memory protection. In this paper we present the case study of IoT in SPHERE (Sensor Platform for HEalthcare in a Residential Environment), a project with the objective to develop a multipurpose, multi-modal sensor platform for monitoring people’s health inside their homes. Atypically for academic projects, in 2017 the SPHERE software is going to be deployed in a 100-home study in volunteer homes, therefore it has to satisfy many real-world requirements. We discuss the requirements for IoT networking in this project, the IoT architecture (built on top of Contiki OS), software engineering challenges and lessons learned, as well as some of the general aspects that still make embedded low-power IoT software development difficult.}, }
Building large-scale low-power Internet of Things (IoT) systems remains a challenge, as these systems have to meet the requirements of reliability, robustness, and energy- efficiency while running on resource-restricted microcontrollers without memory protection. In this paper we present the case study of IoT in SPHERE (Sensor Platform for HEalthcare in a Residential Environment), a project with the objective to develop a multipurpose, multi-modal sensor platform for monitoring people’s health inside their homes. Atypically for academic projects, in 2017 the SPHERE software is going to be deployed in a 100-home study in volunteer homes, therefore it has to satisfy many real-world requirements. We discuss the requirements for IoT networking in this project, the IoT architecture (built on top of Contiki OS), software engineering challenges and lessons learned, as well as some of the general aspects that still make embedded low-power IoT software development difficult.
[7]
X. Fafoutis, A. Vafeas, B. Janko, S. Sherratt, J. Pope, A. Elsts, E. Mellios, G. Hilton, G. Oikonomou, R. Piechocki, I. Craddock, "Designing Wearable Sensing Platforms for Healthcare in a Residential Environment", EAI Endorsed Transactions on Pervasive Health and Technology, European Alliance for Innovation, 17(12), 2017
@article{Fafoutis-2017-eai, title = {Designing Wearable Sensing Platforms for Healthcare in a Residential Environment}, author = {Xenofon Fafoutis and Antonis Vafeas and Balazs Janko and Simon Sherratt and James Pope and Atis Elsts and Evangelos Mellios and Geoffrey Hilton and George Oikonomou and Robert Piechocki and Ian Craddock}, year = {2017}, month = {9}, doi = {10.4108/eai.7-9-2017.153063}, volume = {17}, journal = {EAI Endorsed Transactions on Pervasive Health and Technology}, issn = {2411-7145}, publisher = {European Alliance for Innovation}, number = {12}, gsid = {1445270239734662268}, oa-url = {https://research-information.bristol.ac.uk/en/publications/designing-wearable-sensing-platforms-for-healthcare-in-a-residential-environment(5a9756d4-c840-479d-a989-2e8bbaa9f0ff).html}, abstract = {Wearable technologies are valuable tools that can encourage people to monitor their own well-being and facilitate timely health interventions. In this paper, we present SPW-2; a low-profile versatile wearable sensor that employs two ultra low power accelerometers and an optional gyroscope. Designed for minimum maintenance and a long-term operation outside the laboratory, SPW-2 is able to oer a battery lifetime of multiple months. Measurements on its wireless performance in a real residential environment with thick brick walls, demonstrate that SPW-2 can fully cover a room and - in most cases - the adjacent room, as well.}, }
Wearable technologies are valuable tools that can encourage people to monitor their own well-being and facilitate timely health interventions. In this paper, we present SPW-2; a low-profile versatile wearable sensor that employs two ultra low power accelerometers and an optional gyroscope. Designed for minimum maintenance and a long-term operation outside the laboratory, SPW-2 is able to oer a battery lifetime of multiple months. Measurements on its wireless performance in a real residential environment with thick brick walls, demonstrate that SPW-2 can fully cover a room and - in most cases - the adjacent room, as well.
[6]
A. Mavromatis, G. Papadopoulos, X. Fafoutis, A. Goulianos, G. Oikonomou, P. Chatzimisios, T. Tryfonas, "Link quality and path based clustering in IEEE 802.15.4-2015 TSCH networks", in Proc. IEEE ISCC, pp. 798-803, 2017
@INPROCEEDINGS{Mavromatis-2017-iscc, title = {Link quality and path based clustering in IEEE 802.15.4-2015 TSCH networks}, author = {Alexandros Mavromatis and Georgios Papadopoulos and Xenofon Fafoutis and Angelos Goulianos and George Oikonomou and Periklis Chatzimisios and Theo Tryfonas}, year = {2017}, month = {9}, pages = {798--803}, doi = {10.1109/ISCC.2017.8024625}, booktitle = {Proc. IEEE ISCC}, publisher = {IEEE}, gsid = {10353404964759799904}, oa-url = {https://research-information.bristol.ac.uk/en/publications/link-quality-and-path-based-clustering-in-ieee-8021542015-tsch-networks(11a32dd8-50b3-462a-8204-fe34240a47b0).html}, abstract = {Advance clustering techniques have been widely used in Wireless Sensor Networks (WSNs) since they can potentially reduce latency, improve scheduling, decrease end-to-end delay and optimise energy consumption within a dense network topology. In this paper, we present a novel clustering algorithm for high density IEEE 802.15.4-2015 Time-Slotted Channel Hopping (TSCH). In particular, the proposed methodology merges a variety of solutions into an integrated clustering design. Assuming an homogeneous network distribution, the proposed configuration deploys a hierarchical down-top approach of equally numbered sub-groups, in which the formation of the separate sub-groups is adapted to the network density and the node selection metric is based on the link quality indicator. The presented algorithm is implemented in Contiki Operating System (OS) and several test vectors have been designed in order to evaluate the performance of the proposed algorithm in a COOJA simulation environment. Performance results demonstrate the capability of the clustering structure since compared to the default scheme it significantly improves the energy efficiency up to 35%, packet drops more than 40% as well the packet retransmission rate. Last but not least, the outcome of this study indicates a major increase in the network lifetime, i.e., up to 50%.}, }
Advance clustering techniques have been widely used in Wireless Sensor Networks (WSNs) since they can potentially reduce latency, improve scheduling, decrease end-to-end delay and optimise energy consumption within a dense network topology. In this paper, we present a novel clustering algorithm for high density IEEE 802.15.4-2015 Time-Slotted Channel Hopping (TSCH). In particular, the proposed methodology merges a variety of solutions into an integrated clustering design. Assuming an homogeneous network distribution, the proposed configuration deploys a hierarchical down-top approach of equally numbered sub-groups, in which the formation of the separate sub-groups is adapted to the network density and the node selection metric is based on the link quality indicator. The presented algorithm is implemented in Contiki Operating System (OS) and several test vectors have been designed in order to evaluate the performance of the proposed algorithm in a COOJA simulation environment. Performance results demonstrate the capability of the clustering structure since compared to the default scheme it significantly improves the energy efficiency up to 35%, packet drops more than 40% as well the packet retransmission rate. Last but not least, the outcome of this study indicates a major increase in the network lifetime, i.e., up to 50%.
[5]
@INPROCEEDINGS{Margelis-2017-icc, title = {Physical layer secret-key generation with discreet cosine transform for the Internet of Things}, author = {George Margelis and Xenofon Fafoutis and George Oikonomou and Robert Piechocki and Theo Tryfonas and Paul Thomas}, year = {2017}, month = {7}, doi = {10.1109/ICC.2017.7997419}, isbn = {9781467390002}, booktitle = {Proc. IEEE ICC}, publisher = {IEEE}, gsid = {7131705677557939788}, oa-url = {https://research-information.bristol.ac.uk/en/publications/physical-layer-secretkey-generation-with-discreet-cosine-transform-for-the-internet-of-things(3d03e451-0462-4711-9bd4-c8be5232af9e).html}, abstract = {The confidentiality of communications in the Internet of Things (IoT) is critical, with cryptography currently being the most widely employed method of ensuring it. Establishing cryptographically secure communication links between two transceivers requires the pre-agreement on some key, unknown to an external attacker. In recent years there has been growing attention in techniques that generate a shared random key through observation of the channel and its effects on the exchanged messages. In this work we present SKYGlow, a novel scheme for secret-key generation, designed for IoT devices, such as IEEE 802.15.4 and Bluetooth Low Energy (BLE) transceivers. SKYGlow employs the Discreet Cosine Transform (DCT) of channel observations and Slepian-Wolf coding for information reconciliation. Real-life experiments have resulted in the creation of 128-bit secret keys with only 65 packet exchanges and with an entropy of 0.9978 bits, making our scheme much more energy-efficient compared with others in the existing literature.}, }
The confidentiality of communications in the Internet of Things (IoT) is critical, with cryptography currently being the most widely employed method of ensuring it. Establishing cryptographically secure communication links between two transceivers requires the pre-agreement on some key, unknown to an external attacker. In recent years there has been growing attention in techniques that generate a shared random key through observation of the channel and its effects on the exchanged messages. In this work we present SKYGlow, a novel scheme for secret-key generation, designed for IoT devices, such as IEEE 802.15.4 and Bluetooth Low Energy (BLE) transceivers. SKYGlow employs the Discreet Cosine Transform (DCT) of channel observations and Slepian-Wolf coding for information reconciliation. Real-life experiments have resulted in the creation of 128-bit secret keys with only 65 packet exchanges and with an entropy of 0.9978 bits, making our scheme much more energy-efficient compared with others in the existing literature.
[4]
P. Woznowski, A. Burrows, T. Diethe, X. Fafoutis, J. Hall, S. Hannuna, M. Camplani, N. Twomey, M. Kozlowski, B. Tan, N. Zhu, A. Elsts, A. Vafeas, A. Paiement, L. Tao, M. Mirmehdi, T. Burghardt, D. Damen, P. Flach, R. Piechocki, I. Craddock, G. Oikonomou, "SPHERE: A sensor platform for healthcare in a residential environment", in Designing, Developing, and Facilitating Smart Cities, Springer, pp. 315-333, 2017
@INCOLLECTION{Woznowski-2017-sphere, title = {SPHERE: A sensor platform for healthcare in a residential environment}, author = {Woznowski, {Przemyslaw R.} and Burrows, Alison and Diethe, Tom and Fafoutis, Xenofon and Hall, Jake and Hannuna, Sion and Camplani, Massimo and Twomey, Niall and Kozlowski, Michal and Tan, Bo and Zhu, Ni and Elsts, Atis and Vafeas, Antonis and Paiement, Adeline and Tao, Lili and Mirmehdi, Majid and Burghardt, Tilo and Damen, Dima and Flach, Peter and Piechocki, Robert and Craddock, Ian and Oikonomou, George}, editor = {Angelakis, Vangelis and Tragos, Elias and P{\"o}hls, Henrich C. and Kapovits, Adam and Bassi, Alessandro}, booktitle = {Designing, Developing, and Facilitating Smart Cities}, publisher = {Springer}, gsid = {18162269616817626173}, pages = {315--333}, isbn = {978-3-319-44924-1}, doi = {10.1007/978-3-319-44924-1_14}, year = {2017}, abstract = {It can be tempting to think about smart homes like one thinks about smart cities. On the surface, smart homes and smart cities comprise coherent systems enabled by similar sensing and interactive technologies. It can also be argued that both are broadly underpinned by shared goals of sustainable development, inclusive user engagement and improved service delivery. However, the home possesses unique characteristics that must be considered in order to develop effective smart home systems that are adopted in the real world.}, }
It can be tempting to think about smart homes like one thinks about smart cities. On the surface, smart homes and smart cities comprise coherent systems enabled by similar sensing and interactive technologies. It can also be argued that both are broadly underpinned by shared goals of sustainable development, inclusive user engagement and improved service delivery. However, the home possesses unique characteristics that must be considered in order to develop effective smart home systems that are adopted in the real world.
[3]
@INPROCEEDINGS{Fafoutis-2017-ewsn, title = {Demo: SPES-2 – A Sensing Platform for Maintenance-Free Residential Monitoring}, author = {Xenofon Fafoutis and Atis Elsts and Antonis Vafeas and George Oikonomou and Robert Piechocki}, booktitle = {Proc. EWSN 2017}, year = {2017}, gsid = {17625986834348170975}, oa-url = {http://dl.acm.org/citation.cfm?id=3108009.3108060}, abstract = {SPES-2 is a sensing board for room-level monitoring in a home environment. It constitutes a vital modality of the SPHERE architecture: a multi-modal sensing platform for healthcare in a residential environment. SPES-2 uses an optimised implementation of the IEEE 802.15.4-2015 TSCH (Time-Slotted Channel Hopping) standard to operate efficiently and reliably in unknown environments for more than one year without battery replacement, providing continuous information about the ambient characteristics of the room (such as temperature, humidity and light levels), as well as presence information captured through a motion sensor.} }
SPES-2 is a sensing board for room-level monitoring in a home environment. It constitutes a vital modality of the SPHERE architecture: a multi-modal sensing platform for healthcare in a residential environment. SPES-2 uses an optimised implementation of the IEEE 802.15.4-2015 TSCH (Time-Slotted Channel Hopping) standard to operate efficiently and reliably in unknown environments for more than one year without battery replacement, providing continuous information about the ambient characteristics of the room (such as temperature, humidity and light levels), as well as presence information captured through a motion sensor.
[2]
X. Fafoutis, L. Marchegiani, G. Papadopoulos, R. Piechocki, T. Tryfonas, G. Oikonomou, "Privacy Leakage of Physical Activity Levels in Wireless Embedded Wearable Systems", Signal Processing Letters, IEEE, 24(2), pp. 136-140, 2017
@article{Fafoutis-2016-spl, title = {Privacy Leakage of Physical Activity Levels in Wireless Embedded Wearable Systems}, author = {Xenofon Fafoutis and Letizia Marchegiani and Georgios Papadopoulos and Robert Piechocki and Theo Tryfonas and George Oikonomou}, year = {2017}, doi = {10.1109/LSP.2016.2642300}, oa-url = {http://research-information.bristol.ac.uk/en/publications/privacy-leakage-of-physical-activity-levels-in-wireless-embedded-wearable-systems(4394b8d7-d8fb-4c6e-a91e-06fb9cab6c30).html}, journal = {Signal Processing Letters}, issn = {1070-9908}, publisher = {IEEE}, volume = {24}, number = {2}, pages = {136--140}, gsid = {18301989522027990431}, abstract = {With the ubiquity of sensing technologies in our personal spaces, the protection of our privacy and the confidentiality of sensitive data becomes a major concern. In this paper, we focus on wearable embedded systems that communicate data periodically over the wireless medium. In this context, we demonstrate that private information about the physical activity levels of the wearer can leak to an eavesdropper through the physical layer. Indeed, we show that the physical activity levels strongly correlate with changes in the wireless channel that can be captured by measuring the signal strength of the eavesdropped frames. We practically validate this correlation in several scenarios in a real residential environment, using data collected by our prototype wearable accelerometer-based sensor. Lastly, we propose a privacy enhancement algorithm that<br/>mitigates the leakage of this private information.} }
With the ubiquity of sensing technologies in our personal spaces, the protection of our privacy and the confidentiality of sensitive data becomes a major concern. In this paper, we focus on wearable embedded systems that communicate data periodically over the wireless medium. In this context, we demonstrate that private information about the physical activity levels of the wearer can leak to an eavesdropper through the physical layer. Indeed, we show that the physical activity levels strongly correlate with changes in the wireless channel that can be captured by measuring the signal strength of the eavesdropped frames. We practically validate this correlation in several scenarios in a real residential environment, using data collected by our prototype wearable accelerometer-based sensor. Lastly, we propose a privacy enhancement algorithm that
mitigates the leakage of this private information.
[1]
P. Cooper, K. Maraslis, T. Tryfonas, G. Oikonomou, "An intelligent hot-desking model harnessing the power of occupancy sensing", Journal of Facilities, Emerald Group Publishing Limited, 35(13/14), pp. 766-786, 2017
@ARTICLE{Cooper-2017-jof, title = {An intelligent hot-desking model harnessing the power of occupancy sensing}, author = {Peter Cooper and Konstantinos Maraslis and Theo Tryfonas and George Oikonomou}, journal = {Journal of Facilities}, publisher = {Emerald Group Publishing Limited}, year = {2017}, volume = {35}, number = {13/14}, pages = {766-786}, doi = {doi.org/10.1108/F-01-2016-0014}, oa-url = {https://research-information.bristol.ac.uk/en/publications/an-intelligent-hotdesking-model-harnessing-the-power-of-occupancy-sensing(d9032bd5-17e7-4cf5-9ebe-c8138abcbc86).html}, gsid = {17022844007095112637}, abstract = {In this paper a model is developed to harness the power of occupancy sensing in an Intelligent Hot-Desking system utilizing experimental data from a commercial office in central London. To achieve that, the model uses that data as an input in order to undertake the task of allocating the office desks to the employees in a way that will maximise their productivity based on the type of project that each employee is working on each time. In this way, and by taking into account other parameters that are involved as well, the synergy that this situation can create, can increase productivity significantly compared to the situation where employees have their desks fixed under any circumstances and also allow for expenses cut since the desks can now be less than the employees. Not only is this approach able to optimize desk utilization based on quality occupancy data, but also speculates how and by how much overall productivity increases, while proving that its benefits outweigh the costs of adopting such a system. Furthermore, this paper explores the barriers towards Intelligent Hot-Desking, including how an increase in occupancy data collection in the private sector could have key advantages for the business as an organization and the city as a whole. Ultimately, it provides a valuable and feasible use case for the use of occupancy data in smart buildings, a dataset that is perceived to be valuable yet underexplored.} }
In this paper a model is developed to harness the power of occupancy sensing in an Intelligent Hot-Desking system utilizing experimental data from a commercial office in central London. To achieve that, the model uses that data as an input in order to undertake the task of allocating the office desks to the employees in a way that will maximise their productivity based on the type of project that each employee is working on each time. In this way, and by taking into account other parameters that are involved as well, the synergy that this situation can create, can increase productivity significantly compared to the situation where employees have their desks fixed under any circumstances and also allow for expenses cut since the desks can now be less than the employees. Not only is this approach able to optimize desk utilization based on quality occupancy data, but also speculates how and by how much overall productivity increases, while proving that its benefits outweigh the costs of adopting such a system. Furthermore, this paper explores the barriers towards Intelligent Hot-Desking, including how an increase in occupancy data collection in the private sector could have key advantages for the business as an organization and the city as a whole. Ultimately, it provides a valuable and feasible use case for the use of occupancy data in smart buildings, a dataset that is perceived to be valuable yet underexplored.
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