| 1. |
- Enlund, Desirée, PhD, 1984-, et al.
(author)
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The role of sensors in the production of smart city spaces
- 2022
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In: Big Data and Society. - : SAGE Publications Ltd. - 2053-9517. ; 9:2
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Journal article (peer-reviewed)abstract
- Smart cities build on the idea of collecting data about the city in order for city administration to be operated more efficiently. Within a research project gathering an interdisciplinary team of researchers ? engineers, designers, gender scholars and human geographers ? we have been working together using participatory design approaches to explore how paying attention to the diversity of human needs may contribute to making urban spaces comfortable and safe for more people. The project team has deployed sensors collecting data on air quality, sound and mobility in a smart city testbed in Norrköping, Sweden. While these sensors are meant to capture an accurate ?map? of the street and what is going on along it, our interdisciplinary conversations around the sensors have revealed the heterogeneity both of smart city planning and spatial formulations of the city. The discussions have given rise to questions regarding the work that goes into constructing the sensor box itself, as well as the work of deploying it, and how these influence the ?map? that the sensors produce. In this paper, we draw on Lefebvre to explore how the sensors themselves produce smart spaces. We analyze how the box depends on perceived space to function (e.g. requiring electricity), and simultaneously it produces conceptualizations of space that are influenced by the materiality of the box itself (e.g. sensors being affected by heat and noise). Further, we explore how the (in)visibility of sensor technology influences lived space.
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| 2. |
- Harrison, Katherine, 1977-, et al.
(author)
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Sustainability means inclusivity: Engaging citizens in early stage smart city development
- 2021
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In: PROCEEDINGS OF THE 2020 IEEE INTERNATIONAL SYMPOSIUM ON TECHNOLOGY AND SOCIETY (ISTAS). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665430401 - 9781665415071 ; , s. 413-416
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Conference paper (peer-reviewed)abstract
- The challenge of how cities can be designed and developed in an inclusive and sustainable direction is monumental. Smart city technologies currently offer the most promising solution for long-term sustainability. However, smart city projects have been criticised for ignoring diverse needs of the local population and increasing social divides. A sustainable urban environment depends as much on creating an inclusive space that is safe, accessible and comfortable for a diverse group of citizens as it does on deploying "smart" technologies for energy efficiency or environmental protection. This is because citizens will be more likely to adopt technologies promoting sustainability if they are well-aligned with their lived needs and experiences. In this paper, we present the rationale behind an ongoing interdisciplinary research project that aims to address exactly the problem outlined above by using a participatory design approach. Focusing on a smart city test site in Sweden where sensors are currently being deployed to collect data on noise, particles, vehicle numbers and types (amongst other), the goal is to bring local residents and government representatives into dialogue with technical developers by adopting a "meet-in-the-middle" approach. This paper comprises a brief presentation of early findings and a reflection on this approach.
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| 3. |
- Angelakis, Vangelis, 1977-, et al.
(author)
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A Fully Decentralized and Load-Adaptive Fractional Frequency Reuse Scheme
- 2011
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In: Modeling, Analysis & Simulation of Computer and Telecommunication Systems (MASCOTS), 2011 IEEE 19th International Symposium on. - 9781457704680 ; , s. 425-428
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Conference paper (peer-reviewed)abstract
- A new fully decentralized dynamic fractional frequency reuse (FFR)-based scheme for cellular OFDMA networks is introduced. FFR is a technique to mitigate inter-cell interference to improve the throughput of interference-limited users on the cell edge, to the expense of the rest of the cell's users and the aggregate throughput. The proposed scheme aims to limit the FFR-incurred loss of the center users' throughput, while still providing sufficient bandwidth for the cell edge users' communication. This is done by local information sharing and distributed optimization. The resulting flexibility of frequency reuse can be especially beneficial in scenarios with non-uniform and time-varying load. The optimization task is accomplished by solving a knapsack problem in each cell, where the goal is to maximize the center throughput while maintaining acceptable degradation on the cell edge with respect to the original FFR allocation. The performance improvement resulting from the distributed and dynamic FFR scheme is demonstrated by snapshot simulations on an 81-cells network with asymmetric cell load. The proposed scheme achieves up to a 62% gain in cell-center throughput with a cost of no more than 18% at the edges when compared to the classic FFR scheme. The overall system throughput improvement ranges from 22% to 58%.
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| 4. |
- Avgouleas, Ioannis, 1983-
(author)
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IoT Networking Resource Allocation and Cooperation
- 2017
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Licentiate thesis (other academic/artistic)abstract
- The Internet of Things (IoT) promises that "anything that can be connected, will be connected". It comprises of Information and Communication Technologies that interconnect billions of physical and visual things with some "basic" intelligence. The emerging IoT services will be able to react with minimal human intervention and further contribute to the big data era that requires real-time, ultrareliable, ubiquitous, scalable, and heterogeneous operation.This thesis is the result of our investigations on problems dealing with the evolution of such technologies. First, we explore the potential of using relay i.e., intermediate, nodes that assist users to transmit their packets in a a cellular network. Paper I provides insights into how adapting the cooperation of the relay's receiver and transmitter optimizes the network-wide throughput while the relay's queue stability is guaranteed.The next part of the thesis copes with the resource allocation of services on IoT devices equipped with multiple network interfaces. The resources are heterogeneous and can be split among dierent interfaces. Additionally, they are not interchangeable. In paper II, we develop optimization models for this resource allocation problem, prove the complexity of the models, and derive results that give intuition into the problems. Moreover, we propose algorithms that approximate the optimal solution and show under which circumstances this is possible.Finally, in paper III, we present a resource allocation problem specically for smart cities services. In comparison to the previous problem denition, resources are of one type but the IoT network device can oer capacities that vary over time. Furthermore, services have a tolerance regarding their preferred scheduling, namely, their allocation over time. We parametrize each service with a pricing function to indicate its tolerance to be served at the beginning of the scheduling window. We prove that the problem is computationally hard and provide numerical results to gain insight into how different pricing weight functions impact the allocations' distribution within the scheduling window.
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| 5. |
- Avgouleas, Ioannis M., 1983-
(author)
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Cooperation and Resource Allocation in Wireless Networking towards the IoT
- 2019
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Doctoral thesis (other academic/artistic)abstract
- The Internet of Things (IoT) should be able to react with minimal human intervention and contribute to the Artificial Intelligence (AI) era requiring real-time and scalable operation under heterogeneous network infrastructures. This thesis investigates how cooperation and allocation of resources can contribute to the evolution of future wireless networks supporting the IoT.First, we examine how to allocate resources to IoT services which run on devices equipped with multiple network interfaces. The resources are heterogeneous and not interchangeable, and their allocation to a service can be split among different interfaces. We formulate an optimization model for this allocation problem, prove its complexity, and derive two heuristic algorithms to approximate the solution in large instances of the problem.The concept of virtualization is promising towards addressing the heterogeneity of IoT resources by providing an abstraction layer between software and hardware. Network function virtualization (NFV) decouples traditional network operations such a routing from proprietary hardware platforms and implements them as software entities known as virtualized network functions (VNFs). In the second paper, we study how VNF demands can be allocated to Virtual Machines (VMs) by considering the completion-time tolerance of the VNFs. We prove that the problem is NP-complete and devise a subgradient optimization algorithm to provide near-optimal solutions. Our numerical results demonstrate the effectiveness of our algorithm compared to two benchmark algorithms.Furthermore, we explore the potential of using intermediate nodes, the so-called relays, in IoT networks. In the third paper, we study a multi-user random-access network with a relay node assisting users in transmitting their packets to a destination node. We provide analytical expressions for the performance of the relay's queue and the system throughput. We optimize the relay’s operation parameters to maximize the network-wide throughput while maintaining the relay's queue stability. A stable queue at relay guarantees finite delay for the packets. Furthermore, we study the effect of the wireless links' signal-to-interference-plusnoise ratio (SINR) threshold and the self-interference (SI) cancellation on the per-user and network-wide throughput.Additionally, caching at the network edge has recently emerged as an encouraging solution to offload cellular traffic and improve several performance metrics of the network such as throughput, delay and energy efficiency. In the fourth paper, we study a wireless network that serves two types of traffic: cacheable and non-cacheable traffic. In the considered system, a wireless user with cache storage requests cacheable content from a data center connected with a wireless base station. The user can be assisted by a pair of wireless helpers that exchange non-cacheable content as well. We devise the system throughput and the delay experienced by the user and provide numerical results that demonstrate how they are affected by the non-cacheable packet arrivals, the availability of caching helpers, the parameters of the caches, and the request rate of the user.Finally, in the last paper, we consider a time-slotted wireless system that serves both cacheable and non-cacheable traffic with the assistance of a relay node. The latter has storage capabilities to serve both types of traffic. We investigate how allocating the storage capacity to cacheable and non-cacheable traffic affects the system throughput. Our numerical results provide useful insights into the system throughput e.g., that it is not necessarily beneficial to increase the storage capacity for the non-cacheable traffic to realize better throughput at the non-cacheable destination node.
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| 6. |
- Avgouleas, Ioannis, 1983-, et al.
(author)
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Scheduling Services on an IoT Device Under Time-Weighted Pricing
- 2017
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In: Conference Proceedings IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC). - : IEEE conference proceedings. - 9781538635292 - 9781538635315 - 9781538635308 - 9781538635322 ; , s. 1-5
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Conference paper (peer-reviewed)abstract
- The emerging vision of smart cities necessitates the use of Internet of Things (IoT) network devices to implement sustainable solutions that will improve the operations of urban areas. A massive amount of smart cities services may demand allocation of computational resources, such as processing power or storage, that IoT devices offer. Within this context, we present an IoT network device comprising interfaces with one specific computational resource available. The efficient utilization of available IoT resources would improve the Quality of Service (QoS) of the IoT network that serves the smart city. All resource allocations must be completed within a given scheduling window and every service is parametrized by a pricing weight function to indicate its tolerance to be served at the beginning of the scheduling window. We propose a mathematical optimization formulation to minimize the total cost of allocating all demands within the scheduling window considering the tolerance level of each service at the same time. Moreover, we prove that the problem is computationally hard and we provide numerical results to gain insight into the impact of different pricing weight functions on the allocations’ distribution within the scheduling window.
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| 7. |
- Avgouleas, Ioannis, 1983-, et al.
(author)
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Virtual Network Functions Scheduling under Delay-Weighted Pricing
- 2019
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In: IEEE Networking Letters. - : IEEE. - 2576-3156. ; 1:4, s. 160-163
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Journal article (peer-reviewed)abstract
- We consider a cost minimization problem for High Volume Servers (HVS) equipped with Virtual Machines (VMs) to serve Virtual Network Functions (VNF) demands for resources. Given a scheduling period, a central scheduler decides which VM to use for each VNF demand. Each VM can be activated or disabled with different costs. Each VNF has a delay-weighted pricing function to indicate its completion time tolerance. We prove the NP-completeness of the problem and develop an algorithm based on Lagrangian relaxation and subgradient optimization to deal with this computational complexity. Finally, our numerical results demonstrate our algorithm’s effectiveness compared to two benchmarks.
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| 8. |
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Designing, developing, and facilitating smart cities : urban design to IoT solutions
- 2017
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Editorial collection (other academic/artistic)abstract
- This book discusses how smart cities strive to deploy and interconnect infrastructures and services to guarantee that authorities and citizens have access to reliable and global customized services. The book addresses the wide range of topics present in the design, development and running of smart cities, ranging from big data management, Internet of Things, and sustainable urban planning. The authors cover - from concept to practice – both the technical aspects of smart cities enabled primarily by the Internet of Things and the socio-economic motivations and impacts of smart city development. The reader will find smart city deployment motivations, technological enablers and solutions, as well as state of the art cases of smart city implementations and services. · Provides a single compendium of the technological, political, and social aspects of smart cities; · Discusses how the successful deployment of smart Cities requires a unified infrastructure to support the diverse set of applications that can be used towards urban development; · Addresses design, development and running of smart cities, including big data management and Internet of Things applications.
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| 9. |
- Elshatshat, Mohamed A., et al.
(author)
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Improving the Spectral Efficiency in Dense Heterogeneous Networks Using D2D-Assisted eICIC
- 2018
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In: 2018 IEEE 23rd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538661512 - 9781538661505 - 9781538661529 ; , s. 32-37
-
Conference paper (peer-reviewed)abstract
- Heterogeneous networks (HetNets) that consist of macro base stations (MBSs) and small base stations (SBSs) are a key architectural drive for achieving the high spectral efficiency (SE) in 5G and beyond. Moreover, device-to-device (D2D) communications underlaying mobile networks can provide reliable communications and add SE gains. A major challenge in HetNets is the inter-cell interference (ICI) due to the coexistence of multiple tiers of base stations (BSs). To tackle this challenge, the enhanced inter-cell interference coordination (eICIC) scheme was adopted by 3GPP. In eICIC the MBSs mute their transmission during the so-called ￜalmost blank subframesￜ (ABS). This muting strategy causes resources reduction to the MBS users (MUEs). We propose the use of D2D communications to forward the transmission from the SBS to the MUEs during ABS subframes, by using inactive UEs to relay the downlink transmission, when the destination UEs are outside the coverage of the BS. We use a heuristic resource allocation (RA) algorithm based on the traffic load at the SBSs that integrates eICIC with D2D communications to avoid the service degradation during the time-domain muting. Simulation results of a HetNet with D2D-eICIC show that the SE of our approach outperforms other interference management approaches.
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| 10. |
- Fountoulakis, Emmanouil, 1991-
(author)
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Performance Analysis and Optimization for Time Critical Networking
- 2019
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Licentiate thesis (other academic/artistic)abstract
- Future communication systems will be characterized by heterogeneous traffic and requirements. Time critical applications like cyberphysical systems, augmented and virtual reality, raise the need for a low-latency based network. At the same time, conventional devices requiring for high throughput will co-exist with time critical applications. Besides the new technologies, new scheduling and optimization techniques are needed to face these challenges. In this thesis, we investigate the issues arising from the deployment of these technologies. In Paper I, we explore the benefits of dynamic Transmission Time Interval (TTI) selection in a heterogeneous network environment. We consider packets with deadlines and we optimize jointly the TTI length and the channel allocation. After proving the NP-hardness of the problem, we propose a greedy algorithm taking decisions in polynomial time. The first work opens new questions regarding the deadline-constrained traffic such as how the minimum average drop rate can be achieved. In Paper II, we consider power-limited devices with deadline-constrained traffic. Lyapunov optimization methods are explored to solve the problem with time average objective and constraints. We develop a dynamic, polynomial time, algorithm that finds an approximation of the dropping rate minimization problem under average power constraints. Besides the new techniques, future communication systems will require the development of new technologies for a more exible and elastic network. Multi-access Edge Computing (MEC) and Virtual Network Function (VNF) technologies are considered two of the key technologies for next generation networks. In Paper III, we analyze the performance of a network that hosts VNF and consists of MEC servers and servers at the core. As a first step, we consider a simple end-to-end communication system and provide analytical expressions for the end-to-end delay and system throughput by applying tools from queueing theory. Based on the first step, we provide the methodology for analyzing scaled-up systems with arbitrary number of servers. Simulation results show that our analytical model performs well. Furthermore, this work provides insights for the design and performance optimization of such systems such as optimal ow control and resource allocation.
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