| 1. |
- Corneo, Lorenzo
(författare)
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Networked Latency Sensitive Applications - Performance Issues between Cloud and Edge
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing demand for industrial automation has motivated the development of applications with strict latency requirements, namely, latency-sensitive applications. Such latency requirements can be satisfied by offloading computationally intensive tasks to powerful computing devices over a network at the cost of additional communication latency. Two major computing paradigms are considered for this: (i) cloud computing and (ii) edge computing. Cloud computing provides computation at remote datacenters, at the cost of longer communication latency. Edge computing aims at reducing communication latency by bringing computation closer to the users. This doctoral dissertation mainly investigates relevant issues regarding communication latency trade-offs between the aforementioned paradigms in the context of latency-sensitive applications.This work advances the state of the art with three major contributions. First, we design a suite of scheduling algorithms which are performed on an edge device interposed between a co-located sensor network and remote applications running in cloud datacenters. These algorithms guarantee the fulfillment of latency-sensitive applications' requirements while maximizing the battery life of sensing devices. Second, we estimate under what conditions latency-sensitive applications can be executed in cloud environments. From a broader perspective, we quantify round-trip times needed to access cloud datacenters all around the world. From a narrower perspective, we collect latency measurements to cloud datacenters in metropolitan areas where over 70% of the world's population lives. This Internet-wide large-scale measurements campaign allows us to draw statistically relevant conclusions concerning the readiness of the cloud environments to host latency-sensitive applications. Finally, we devise a method to quantify latency improvements that hypothetical edge server deployments could bring to users within a network. This is achieved with a thorough analysis of round-trip times and paths characterization resulting in the design of novel edge server placement algorithms. We show trade-offs between number of edge servers deployed and latency improvements experienced by users.This dissertation contributes to the understanding of the communication latency in terms of temporal and spacial distributions, its sources and implications on latency-sensitive applications.
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| 2. |
- 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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| 3. |
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| 4. |
- Eriksson, Joakim
(författare)
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Scalable and Interoperable Low-Power Internet of Things Networks
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internet of Things (IoT) is the concept of connecting devices to the Internet. IoT devices can be anything from small temperature sensors to self-driving cars. The devices are typically resource-constrained, connected wirelessly, and often battery-powered. In this thesis, we address energy efficiency and the tools required for estimating power consumption, interoperability between different implementations of IoT protocols, and scalability of the IoT networks in mesh configurations. The contributions are made in the five included research papers addressing these challenges. Firstly, we present and evaluate network-wide energy estimation support in our simulation tool COOJA/MSPSim. Due to the timing accuracy of the simulation and emulation, we get energy consumption estimates very close to hardware-based estimates. The second contribution evaluates the capabilities of simulation tools for interoperability testing. We show that it is possible to set up simulations of networks with multiple implementations of the same open standards (6LoWPAN/RPL) and that it is possible to get results beyond pure interoperability, including power consumption and network quality. Finally, we show that, by carefully managing neighbor updates, it is possible to scale IoT networks even when the IoT devices' memory limitations severely constrain the size of the neighbor table.The experimental systems research that resulted in this thesis also provided significant contributions to the open-source ecosystem around Contiki, an operating system for resource-constrained IoT devices. This software, Contiki and COOJA/MSPSim, has been a cornerstone in our capability to perform sound systems research and has been widely used by other research groups in resource-constrained IoT research in academia and many companies for developing commercial IoT devices.
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| 5. |
- Orfanidis, Charalampos
(författare)
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Robustness in low power wide area networks
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the past few years we have witnessed an emergence of Wide Area Networks in the Internet of Things area. There are several new technologies like LoRa, Wi-SUN, Sigfox, that offer long range communication and low power for low-bitrate applications. These new technologies enable new application scenarios, such as smart cities, smart agriculture, and many more. However, when these networks co-exist in the same frequency band, they may cause problems to each other since they are heterogeneous and independent. Therefore it is very likely to have frame collisions between the different networks.In this thesis we first explore how tolerant these networks are to Cross Technology Interference (CTI). CTI can be described as the interference from heterogeneous wireless technologies that share the same frequency band and is able to affect the robustness and reliability of the network. In particular, we select two of them, LoRa and Wi-SUN and carry out a series of experiments with real hardware using several configurations. In this way, we quantify the tolerance of cross technology interference of each network against the other as well as which configuration settings are important.The next thing we explored is how well channel sensing mechanisms can detect the other network technologies and how they can be improved. For exploring these aspects, we used the default Clear Channel Assessment (CCA) mechanism of Wi-SUN against LoRa interference and we evaluated how accurate it is. We also improved this mechanism in order to have higher accuracy detection against LoRa interference.Finally, we propose an architecture for WSNs which will enable flexible reconfiguration of the nodes. The idea is based on Software Defined Network (SDN) principles and could help on our case by reconfiguring a node in order to mitigate the cross-technology interference from other networks.
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| 6. |
- Corneo, Lorenzo, et al.
(författare)
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(How Much) Can Edge Computing Change Network Latency?
- 2021
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Ingår i: 2021 IFIP Networking Conference (IFIP Networking). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665445016 - 9783903176393 ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- Edge computing aims to enable applications with stringent latency requirements, e.g., augmented reality, and tame the overwhelming data streams generated by IoT devices. A core principle of this paradigm is to bring the computation from a distant cloud closer to service consumers and data producers. Consequentially, the issue of edge computing facilities’ placement arises. We present a comprehensive analysis suggesting where to place general-purpose edge computing resources on an Internet-wide scale. We base our conclusions on extensive real-world network measurements. We perform extensive traceroute measurements from RIPE Atlas to datacenters in the US, resulting in a graph of 11K routers. We identify the affiliations of the routers to determine the network providers that can act as edge providers. We devise several edge placement strategies and show that they can improve cloud access latency by up to 30%.
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| 7. |
- Corneo, Lorenzo, et al.
(författare)
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Surrounded by the Clouds : A Comprehensive Cloud Reachability Study
- 2021
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Ingår i: Proceedings Of The World Wide Web Conference 2021 (WWW 2021). - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450383127 ; , s. 295-304, s. 295-304
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Konferensbidrag (refereegranskat)abstract
- In the early days of cloud computing, datacenters were sparsely deployed at distant locations far from end-users with high end-toend communication latency. However, today's cloud datacenters have become more geographically spread, the bandwidth of the networks keeps increasing, pushing the end-users latency down. In this paper, we provide a comprehensive cloud reachability study as we perform extensive global client-to-cloud latency measurements towards 189 datacenters from all major cloud providers. We leverage the well-known measurement platform RIPE Atlas, involving up to 8500 probes deployed in heterogeneous environments, e.g., home and offices. Our goal is to evaluate the suitability of modern cloud environments for various current and predicted applications. We achieve this by comparing our latency measurements against known human perception thresholds and are able to draw inferences on the suitability of current clouds for novel applications, such as augmented reality. Our results indicate that the current cloud coverage can easily support several latency-critical applications, like cloud gaming, for the majority of the world's population.
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| 8. |
- Khan, Talha, et al.
(författare)
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BATTERY LIFE-TIME OPTIMIZATION FOR LOW POWER DEVICES
- 2022
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Patent (populärvet., debatt m.m.)abstract
- A network node determines a voltage response characteristic of the battery in a low powered user equipment and controls the activity pattern of the user equipment to align its activity pattern with the voltage response characteristic of the battery to extend the useful life of the battery in the user equipment.
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| 9. |
- Khan, Talha, et al.
(författare)
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BATTERY LIFE-TIME PREDICTION FOR LOW POWER DEVICES
- 2022
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Patent (populärvet., debatt m.m.)abstract
- A network node is configured to monitor battery usage on behalf of the low power device and to predict the SOC and remaining life-time for the batteries in the low power devices. The network nodes are fully powered and have the computational capacity to use more complex and accurate models that are not feasible for implementation in resource-limited devices. The network node can calculate the SOC and remaining life-time for a low power device and may also change the transmission and reception patterns for the device to extend the life-time of the battery.
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