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Gonzalo Peces, C., Eriksson, J. & Tsiftes, N. (2019). Sleepy Devices Versus Radio Duty Cycling: The Case of Lightweight M2M. IEEE Internet of Things Journal, 6(2), 2550-2562
Open this publication in new window or tab >>Sleepy Devices Versus Radio Duty Cycling: The Case of Lightweight M2M
2019 (English)In: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 6, no 2, p. 2550-2562Article in journal (Refereed) Published
Abstract [en]

Standard protocols for wireless Internet of Things (IoT) communication must be energy-efficient in order to prolong the lifetimes of IoT devices. Two energy-saving strategies for wireless communication are prevalent within the IoT domain: 1) sleepy devices and 2) radio duty cycling. In this paper, we conduct a comprehensive evaluation as to what types of application scenarios benefit the most from either type of energy-saving strategy. We select the lightweight machine to machine (LwM2M) protocol for this purpose because it operates atop the standard constrained application protocol, and has support for sleepy devices through its Queue Mode. We implement the Queue Mode at both the server side and client side, and design enhancements of Queue Mode to further improve the performance. In our experimental evaluation, we compare the performance and characteristics of Queue Mode with that of running LwM2M in a network stack with the standard time-slotted channel hopping as the duty cycling medium access control protocol. By analyzing the results with the support of an empirical model, we find that each energy-saving strategy has different advantages and disadvantages depending on the scenario and traffic pattern. Hence, we also produce guidelines that can help developers to select the appropriate energy-saving strategy based on the application scenario.

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
802.15.4, Internet of Things, LwM2M, TSCH
National Category
Computer Sciences
Identifiers
urn:nbn:se:ri:diva-39258 (URN)10.1109/JIOT.2018.2871721 (DOI)
Funder
Knowledge FoundationEU, Horizon 2020, 646184
Available from: 2019-06-28 Created: 2019-06-28 Last updated: 2019-07-02Bibliographically approved
Peces, C., Eriksson, J. & Tsiftes, N. (2019). Sleepy Devices vs. Radio Duty Cycling: The Case of Lightweight M2M. IEEE Internet of Things Journal, 6(2), 2550-2562, Article ID 8470064.
Open this publication in new window or tab >>Sleepy Devices vs. Radio Duty Cycling: The Case of Lightweight M2M
2019 (English)In: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 6, no 2, p. 2550-2562, article id 8470064Article in journal (Refereed) Published
Abstract [en]

Standard protocols for wireless IoT communication must be energy-efficient in order to prolong the lifetimes of IoT devices. Two energy-saving strategies for wireless communication are prevalent within the IoT domain: sleepy devices and radio duty cycling. In this paper, we conduct a comprehensive evaluation as to what types of application scenarios benefit the most from either type of energy-saving strategy. We select the Lightweight Machine to Machine (LwM2M) protocol for this purpose because it operates atop the standard Constrained Application Protocol (CoAP), and has support for sleepy devices through its Queue Mode. We implement the Queue Mode at both the server side and client side, and design enhancements of Queue Mode to further improve the performance. In our experimental evaluation, we compare the performance and characteristics of Queue Mode with that of running LwM2M in a network stack with the standard Time-Slotted Channel Hopping (TSCH) as the duty cycling MAC protocol. By analyzing the results with the support of an empirical model, we find that each energy-saving strategy has different advantages and disadvantages depending on the scenario and traffic pattern. Hence, we also produce guidelines that can help developers to select the appropriate energy-saving strategy based on the application scenario.

Keywords
Servers, Standards, Media Access Protocol, Performance evaluation, Internet of Things, Wireless communication
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36365 (URN)10.1109/JIOT.2018.2871721 (DOI)2-s2.0-85054219063 (Scopus ID)
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-07-01Bibliographically approved
Köckemann, U., Tsiftes, N. & Loutfi, A. (2018). Integrating Constraint-based Planning with LwM2M for IoT Network Scheduling. In: : . Paper presented at Workshop on AI for Internet of Things (AI4IoT), Stockholm, July 15, 2018.
Open this publication in new window or tab >>Integrating Constraint-based Planning with LwM2M for IoT Network Scheduling
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This paper describes the design and implementationof a network scheduler prototype for IoT networks within the e-healthcare domain. The network scheduler combines a constraint-based task planner with the Lightweight Machine-to-Machine (LwM2M) protocol to be able to reconfigure IoT networks at run-time based on recognized activities and changes in the environment. To support such network scheduling, we implement a LwM2M application layer for the IoT devices that provides sensor data, network stack information, and a set of controllable parameters that affect the communication performance and the energy consumption.

Keywords
LwM2M, Internet of Things, network scheduling, e-healthcare
National Category
Computer Sciences
Identifiers
urn:nbn:se:ri:diva-33949 (URN)
Conference
Workshop on AI for Internet of Things (AI4IoT), Stockholm, July 15, 2018
Funder
Knowledge Foundation
Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2018-06-28Bibliographically approved
Ahmed, M. U., Fotouhi, H., Köckemann, U., Lindén, M., Tomasic, I., Tsiftes, N. & Voigt, T. (2018). Run-Time Assurance for the E-care@home System. In: Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 225): . Paper presented at International Conference on IoT Technologies for HealthCare HealthyIoT 2017: Internet of Things (IoT) Technologies for HealthCare. 24 October 2017 through 25 October 2017 (pp. 107-110).
Open this publication in new window or tab >>Run-Time Assurance for the E-care@home System
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2018 (English)In: Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 225), 2018, p. 107-110Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents the design and implementation of the software for a run-time assurance infrastructure in the E-care@home system. An experimental evaluation is conducted to verify that the run-time assurance infrastructure is functioning correctly, and to enable detecting performance degradation in experimental IoT network deployments within the context of E-care@home. © 2018, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

Keywords
Health care, Care homes, Design and implementations, Experimental evaluation, IOT networks, Performance degradation, Runtimes, Internet of things
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33463 (URN)10.1007/978-3-319-76213-5_15 (DOI)2-s2.0-85042521264 (Scopus ID)9783319762128 (ISBN)
Conference
International Conference on IoT Technologies for HealthCare HealthyIoT 2017: Internet of Things (IoT) Technologies for HealthCare. 24 October 2017 through 25 October 2017
Note

 Funding details: 2015–2019, Knowledge Foundation; .

Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-07-20Bibliographically approved
Eriksson, J., Finne, N., Tsiftes, N., Duquennoy, S. & Voigt, T. (2018). Scaling RPL to Dense and Large Networks with Constrained Memory. In: Proceedings of the 2018 International Conference on Embedded Wireless Systems and Networks: . Paper presented at EWSN ’18 Proceedings of the 2018 International Conference on Embedded Wireless Systems and Networks Madrid, Spain — February 14 - 16, 2018 (pp. 126-134).
Open this publication in new window or tab >>Scaling RPL to Dense and Large Networks with Constrained Memory
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2018 (English)In: Proceedings of the 2018 International Conference on Embedded Wireless Systems and Networks, 2018, p. 126-134Conference paper, Published paper (Refereed)
Abstract [en]

The Internet of Things poses new requirements for reliable, bi-directional communication in low-power and lossy networks, but these requirements are hard to fulfill since most existing protocols have been designed for data collection. In this paper, we propose standard-compliant mechanisms that make RPL meet these requirements while still scaling to large networks of IoT devices under significant resource constraints. Our aim is to scale far beyond what can be stored in RAM on the nodes of the network. The only node that needs to have storage for all the routing entries is the RPL root node. Based on experimentation with largescale commercial deployments, we suggest two mechanisms to make RPL scale under resource constraints: (1) end-to-end route registration with DAO and (2) a policy for managing the neighbor table. By employing these mechanisms, we show that the bi-directional packet reception rate of RPL networks increases significantly.

Keywords
RPL, Scalability, Wireless Networking
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36441 (URN)
Conference
EWSN ’18 Proceedings of the 2018 International Conference on Embedded Wireless Systems and Networks Madrid, Spain — February 14 - 16, 2018
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2018-12-17Bibliographically approved
Tsiftes, N. & Voigt, T. (2018). Velox VM: A safe execution environment for resource-constrained IoT applications. Journal of Network and Computer Applications, 118, 61-73
Open this publication in new window or tab >>Velox VM: A safe execution environment for resource-constrained IoT applications
2018 (English)In: Journal of Network and Computer Applications, ISSN 1084-8045, E-ISSN 1095-8592, Vol. 118, p. 61-73Article in journal (Refereed) Published
Abstract [en]

We present Velox, a virtual machine architecture that provides a safe execution environment for applications in resource-constrained IoT devices. Our goal with this architecture is to support developers in writing and deploying safe IoT applications, in a manner similar to smartphones with application stores. To this end, we provide a resource and security policy framework that enables fine-grained control of the execution environment of IoT applications. This framework allows device owners to configure, e.g., the amount of bandwidth, energy, and memory that each IoT application can use. Velox's features also include support for high-level programming languages, a compact bytecode format, and preemptive multi-threading.

In the context of IoT devices, there are typically severe energy, memory, and processing constraints that make the design and implementation of a virtual machine with such features challenging. We elaborate on how Velox is implemented in a resource-efficient manner, and describe our port of Velox to the Contiki OS. Our experimental evaluation shows that we can control the resource usage of applications with a low overhead. We further show that, for typical I/O-driven IoT applications, the CPU and energy overhead of executing Velox bytecode is as low as 1–5% compared to corresponding applications compiled to machine code. Lastly, we demonstrate how application policies can be used to mitigate the possibility of exploiting vulnerable applications.

Keywords
Internet of things, Embedded systems, Virtual machine, Resource management, Policy enforcement, High-level programming
National Category
Computer Sciences
Identifiers
urn:nbn:se:ri:diva-33948 (URN)10.1016/j.jnca.2018.06.001 (DOI)2-s2.0-85048323589 (Scopus ID)
Funder
VINNOVAKnowledge Foundation
Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2019-01-10Bibliographically approved
Alirezaie, M., Renoux, J., Köckemann, U., Kristoffersson, A., Karlsson, L., Blomqvist, E., . . . Loutfi, A. (2017). An ontology-based context-aware system for smart homes: E-care@home. Sensors, 17(7), Article ID 1586.
Open this publication in new window or tab >>An ontology-based context-aware system for smart homes: E-care@home
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2017 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7, article id 1586Article in journal (Refereed) Published
Abstract [en]

Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

Keywords
Activity recognition, Ambient assisted living, Context awareness, Internet of Things, Ontologies, Smart homes, Assisted living, Automation, Intelligent buildings, Ontology, Semantics, User interfaces, Context- awareness, Environmental parameter, Integrating measurement, Ontology-based context, Semantic interpretation, Home health care
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-30269 (URN)10.3390/s17071586 (DOI)2-s2.0-85021911117 (Scopus ID)
Available from: 2017-08-10 Created: 2017-08-10 Last updated: 2019-06-20Bibliographically approved
Ahmed, M. U., Fotouhi, H., Köckemann, U., Lindén, M., Tomasic, I., Tsiftes, N. & Voigt, T. (2017). Run-Time Assurance for the E-care@home System. In: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST: . Paper presented at 4th EAI International Conference on IoT Technologies for HealthCare (HealthyIoT), Angers, France, 24-25 Oct 2017 (pp. 107-110). , 225
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2017 (English)In: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST, 2017, Vol. 225, p. 107-110Conference paper, Poster (with or without abstract) (Refereed)
National Category
Computer Sciences
Identifiers
urn:nbn:se:ri:diva-32953 (URN)10.1007/978-3-319-76213-5_15 (DOI)2-s2.0-85042521264 (Scopus ID)9783319762128 (ISBN)
Conference
4th EAI International Conference on IoT Technologies for HealthCare (HealthyIoT), Angers, France, 24-25 Oct 2017
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2019-01-31Bibliographically approved
Michel, M., Voigt, T., Tsiftes, N., Mottola, L. & Quoitin, B. (2016). Predictable MAC-level Performance in Low-power Wireless under Interference (9ed.). In: Proceedings of the 2016 International Conference on Embedded Wireless Systems and Networks: . Paper presented at International Conference on Embedded Wireless Systems and Networks (EWSN 2016), February 15-17, 2016, Graz, Austria (pp. 13-22).
Open this publication in new window or tab >>Predictable MAC-level Performance in Low-power Wireless under Interference
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2016 (English)In: Proceedings of the 2016 International Conference on Embedded Wireless Systems and Networks, 2016, 9, p. 13-22Conference paper, Published paper (Refereed)
Abstract [en]

Predictable performance is key for many WSN applications. Recent efforts use models of the environment, the employed hardware, and protocols to predict network performance. Towards this end, we present an intentionally simple model of ContikiMAC, Contiki’s default MAC layer, targeting worst-case bounds for packet delivery rate and latency. Our experiments reveal problems in the performance of ContikiMAC, which make the protocol perform much worse than predicted, and hence prohibit predictable performance with the current ContikiMAC implementation. We show that the reason for this performance degradation is that ContikiMAC loses phase-lock. To solve this problem, we add fine-grained timing information into the acknowledgment packets. We show that this mechanism solves these problems and enables predictable performance with ContikiMAC even under high external interference.

National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-24534 (URN)978-0-9949886-0-7 (ISBN)
Conference
International Conference on Embedded Wireless Systems and Networks (EWSN 2016), February 15-17, 2016, Graz, Austria
Projects
RELYonITE-care@Home
Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2019-06-25Bibliographically approved
Tsiftes, N., Duquennoy, S., Voigt, T., Ahmed, M. U., Köckemann, U. & Loutfi, A. (2016). The E-Care@Home Infrastructure for IoT-Enabled Healthcare (8ed.). In: Internet of Things Technologies for HealthCare: . Paper presented at 3rd EAI International Conference on IoT Technologies for HealthCare (HealthyIoT 2016), October 18-19, 2016, Västerås, Sweden (pp. 138-140). Springer, 187
Open this publication in new window or tab >>The E-Care@Home Infrastructure for IoT-Enabled Healthcare
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2016 (English)In: Internet of Things Technologies for HealthCare, Springer, 2016, 8, Vol. 187, p. 138-140Conference paper, Published paper (Refereed)
Abstract [en]

The E-Care@Home Project aims at providing a comprehensive IoT-based healthcare system, including state-of-the-art communication protocols and high-level analysis of data from various types of sensors. With this poster, we present its novel technical infrastructure, consisting of low-power IPv6 networking, sensors for health monitoring, and resource-efficient software, that is used to gather data from elderly patients and their surrounding environment.

Place, publisher, year, edition, pages
Springer, 2016 Edition: 8
Series
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering (LNICST), ISSN 1867-8211 ; 187
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-24571 (URN)10.1007/978-3-319-51234-1_22 (DOI)978-3-319-51233-4 (ISBN)978-3-319-51234-1 (ISBN)
Conference
3rd EAI International Conference on IoT Technologies for HealthCare (HealthyIoT 2016), October 18-19, 2016, Västerås, Sweden
Projects
E-Care@Home
Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2019-06-26Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3139-2564

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