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  • 1. Abourraja, Mohamed Nezar
    et al.
    Oudani, Mustapha
    Samiri, Mohamed Yassine
    Boudebous, Dalila
    El Fazziki, Abdelaziz
    Najib, Mehdi
    Bouain, Abdelhadi
    Rouky, Naoufal
    A multi-agent based simulation model for rail–rail transshipment: An engineering approach for gantry crane scheduling2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, s. 13142-13156Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Le Havre Port Authority is putting into service a multimodal hub terminal with massified hinterland links (trains and barges) in order to restrict the intensive use of roads, to achieve a more attractive massification share of hinterland transportation and to provide a river connection to its maritime terminals that do not currently have one. This paper focuses on the rail-rail transshipment yard of this new terminal. In the current organizational policy, this yard is divided into two equal operating areas, and, in each one, a crane is placed, and it is equipped with reach stackers to enable container moves across both operating areas. However, this policy causes poor scheduling of crane moves, because it gives rise to many crane interference situations. For the sake of minimizing the occurrence of these undesirable situations, this paper proposes a multi-agent simulation model including an improved strategy for crane scheduling. This strategy is inspired by the ant colony approach and it is governed by a new configuration for the rail yard's working area that eliminates the use of reach stackers. The proposed simulation model is based on two planner agents, to each of which a time-horizon planning is assigned. The simulation results show that the model developed here is very successful in significantly reducing unproductive times and moves (undesirable situations), and it outperforms other existing simulation models based on the current organizational policy.

  • 2.
    Ahmad, Sarosh
    et al.
    Govt Coll Univ Faisalabad GCUF, Dept Elect Engn & Technol, Faisalabad 38000, Pakistan.;Univ Carlos III Madrid, Dept Signal Theory & Commun, Madrid 28911, Spain..
    Khan, Shahid
    COMSATS Univ Islamabad, Dept Elect & Comp Engn, Abbottabad Campus, Abbottabad 22060, Pakistan.;Univ Lorraine, Inst Super Elect & Automat, F-57070 Lorraine, France..
    Manzoor, Bilal
    Univ Engn & Technol UET, Dept Telecom Engn, Taxila 47050, Pakistan..
    Soruri, Mohammad
    Univ Birjand, Tech Fac Ferdows, Birjand 9717434765, Iran..
    Alibakhshikenari, Mohammad
    Univ Carlos III Madrid, Dept Signal Theory & Commun, Madrid 28911, Spain..
    Dalarsson, Mariana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Falcone, Francisco
    Univ Publ Navarra, Elect Elect & Commun Engn Dept, Pamplona 31006, Spain.;Univ Publ Navarra, Inst Smart Cities, Pamplona 31006, Spain..
    A Compact CPW-Fed Ultra-Wideband Multi-Input-Multi-Output (MIMO) Antenna for Wireless Communication Networks2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 25278-25289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, a compact coplanar waveguide (CPW) technique based ultra-wideband multiple-input-multiple-output (MIMO) antenna is proposed. The design is characterized by a broad impedance bandwidth starting from 3 GHz to 11 GHz. The overall size of the MIMO design is 60 x 60 mm(2) (1.24 x 1.24 lambda(2)(g) @ 3 GHz) with a thickness of 1.6 mm. To make the design ultra-wideband, the proposed MIMO antenna design has four jug-shaped radiating elements. The design is printed on a FR-4 substrate (relative permittivity of epsilon(r) = 4.4 and loss tangent of tan delta = 0.025). The polarization diversity phenomenon is realized by placing four antenna elements orthogonally. This arrangement increases the isolation among the MIMO antenna elements. The simulated results of the ultra-wideband MIMO antenna are verified by measured results. The proposed MIMO antenna has a measured diversity gain greater than 9.98, envelope correlation coefficient (ECC) less than 0.02, and good MIMO performance where the isolation is more than -20dB between the elements. The group delay, channel capacity loss (CCL), and the total active reflection coefficient (TARC) multiplexing efficiency and mean effective gain results are also analyzed. The group delay is found to be less than 1.2ns, CCL values calculated to be less than 0.4 bits/sec/Hz, while the TARC is below -10dB for the whole operating spectrum. The proposed design is a perfect candidate for ultra-wideband wireless communication systems and portable devices.

  • 3.
    Alibakhshikenari, Mohammad
    et al.
    Univ Carlos III Madrid, Dept Signal Theory & Commun, Madrid 28911, Spain..
    Ali, Esraa Mousa
    Amman Arab Univ, Fac Aviat Sci, Amman 11953, Jordan..
    Soruri, Mohammad
    Univ Birjand, Tech Fac Ferdows, Birjand 9717434765, Iran..
    Dalarsson, Mariana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Naser-Moghadasi, Mohammad
    Islamic Azad Univ, Sci & Res Branch, Dept Elect & Comp Engn, Tehran 1477893855, Iran..
    Virdee, Bal S.
    London Metropolitan Univ, Sch Comp & Digital Media, Ctr Commun Technol, London N7 8DB, England..
    Stefanovic, Caslav
    Univ Carlos III Madrid, Dept Signal Theory & Commun, Madrid 28911, Spain..
    Pietrenko-Dabrowska, Anna
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, PL-80233 Gdansk, Poland..
    Koziel, Slawomir
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, PL-80233 Gdansk, Poland.;Reykjavik Univ, Engn Optimizat & Modeling Ctr, IS-101 Reykjavik, Iceland..
    Szczepanski, Stanislaw
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, PL-80233 Gdansk, Poland..
    Limiti, Ernesto
    Univ Roma Tor Vergata, Elect Engn Dept, I-00133 Rome, Italy..
    A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 3668-3692Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Antennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside electronic devices. Although on-chip antennas have a limited range, they are suitable for cell phones, tablet computers, headsets, global positioning system (GPS) devices, and WiFi and WLAN routers. Typically, on-chip antennas are handicapped by narrow bandwidth (less than 10%) and low radiation efficiency. This survey provides an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeter-waves (mmWave) and terahertz (THz) integrated-circuit (IC) applications. The technologies discussed here include metamaterial (MTM), metasurface (MTS), and substrate integrated waveguides (SIW). The antenna designs described here are implemented on various substrate layers such as Silicon, Graphene, Polyimide, and GaAs to facilitate integration on ICs. Some of the antennas described here employ innovative excitation mechanisms, for example comprising open-circuited microstrip-line that is electromagnetically coupled to radiating elements through narrow dielectric slots. This excitation mechanism is shown to suppress surface wave propagation and reduce substrate loss. Other techniques described like SIW are shown to significantly attenuate surface waves and minimise loss. Radiation elements based on the MTM and MTS inspired technologies are shown to extend the effective aperture of the antenna without compromising the antenna's form factor. Moreover, the on-chip antennas designed using the above technologies exhibit significantly improved impedance match, bandwidth, gain and radiation efficiency compared to previously used technologies. These features make such antennas a prime candidate for mmWave and THz on-chip integration. This review provides a thorough reference source for specialist antenna designers.

  • 4.
    Almas, Muhammad Shoaib
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Vanfretti, Luigi
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik. Statnett.
    A Hybrid Synchrophasor and GOOSE-Based Power System Synchronization Scheme2016Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 4, s. 4659-4668Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design and real-time hardware-in-the-loop implementation of a hybrid synchrophasors and GOOSE-based automatic synchronization algorithm are presented in this paper. Automatic synchronization is performed by utilizing the synchrophasor measurements from two commercial phasor measurement units (PMUs), while the coordinated control commands to automatic voltage regulator and/or turbine governor control and trip command to the circuit breaker are issued using IEC 61850-8-1 GOOSE messages. The algorithm is deployed inside the PMU using the protection logic equations, and direct communication between the PMUs is established to minimize the communication latencies. In addition, the algorithm is tested using a standard protection relay test-set, and automatic test sequences are executed to validate its performance. It is concluded that the hybrid synchrophasor and GOOSE-based automatic synchronization scheme ensures minimum communication latencies, reduces equipment cost, facilitates interoperability, and performs automatic reconnection adequately.

  • 5.
    Alsayfi, Majed S.
    et al.
    Taibah Univ, Coll Comp Sci & Engn, Dept Comp Sci, Medina 42353, Saudi Arabia.;King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Dahab, Mohamed Y.
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Eassa, Fathy E.
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Salama, Reda
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Informat Technol, Jeddah 21589, Saudi Arabia..
    Haridi, Seif
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Al-Ghamdi, Abdullah S.
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Informat Syst, Jeddah 21589, Saudi Arabia..
    Securing Real-Time Video Surveillance Data in Vehicular Cloud Computing: A Survey2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 51525-51547Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vehicular ad hoc networks (VANETs) have received a great amount of interest, especially in wireless communications technology. In VANETs, vehicles are equipped with various intelligent sensors that can collect real-time data from inside and from surrounding vehicles. These real-time data require powerful computation, processing, and storage. However, VANETs cannot manage these real-time data because of the limited storage capacity in on board unit (OBU). To address this limitation, a new concept is proposed in which a VANET is integrated with cloud computing to form vehicular cloud computing (VCC) technology. VCC can manage real-time services, such as real-time video surveillance data that are used for monitoring critical events on the road. These real-time video surveillance data include highly sensitive data that should be protected against intruders in the networks because any manipulation, alteration, or sniffing of data will affect a driver's life by causing improper decision-making. The security and privacy of real-time video surveillance data are major challenges in VCC. Therefore, this study reviewed the importance of the security and privacy of real-time video data in VCC. First, we provide an overview of VANETs and their limitations. Second, we provide a state-of-the-art taxonomy for real-time video data in VCC. Then, the importance of real-time video surveillance data in both fifth generation (5G), and sixth generation (6G) networks is presented. Finally, the challenges and open issues of real-time video data in VCC are discussed.

  • 6.
    Amizhtan, S. K.
    et al.
    Indian Inst Technol Madras, Dept Elect Engn, Chennai 600036, Tamil Nadu, India..
    Amalanathan, A. J.
    Indian Inst Technol Madras, Dept Elect Engn, Chennai 600036, Tamil Nadu, India..
    Sarathi, R.
    Indian Inst Technol Madras, Dept Elect Engn, Chennai 600036, Tamil Nadu, India..
    Srinivasan, Balaji
    Indian Inst Technol Madras, Dept Elect Engn, Chennai 600036, Tamil Nadu, India..
    Gardas, Ramesh L.
    Indian Inst Technol Madras, Dept Chem, Chennai 600036, Tamil Nadu, India..
    Edin, Hans Ezz
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Taylor, Nathaniel
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Impact of Surfactants on the Electrical and Rheological Aspects of Silica Based Synthetic Ester Nanofluids2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 18192-18200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study reports experimental investigations of the effects of different surfactants (CTAB, Oleic acid and Span 80) on silica based synthetic ester nanofluids. The positive and negative potential observed for the ionic (CTAB) and non-ionic surfactant (Span 80) from zeta potential analysis indicates an improved stability. The optimization of nanofillers and surfactants is performed considering the corona inception voltage measured using ultra high frequency (UHF) technique and fluorescent fiber. Rheological analysis shows no significant variation of properties with shear rate, implying Newtonian behavior even with the addition of surfactant. In addition, the permittivity of the nanofluid is not much affected by adding surfactant but a marginal variation is noticed in the loss tangent with the effect of temperature. The fluorescence spectroscopy shows no change in the emission wavelength with the addition of silica nanofiller and surfactants. Flow electrification studies indicate an increase in the streaming current with the rotation speed and temperature, with a higher current magnitude observed in the case of nanofluids.

  • 7.
    Apiola, Mikko
    et al.
    Univ Turku, Dept Comp, Turku 20500, Finland..
    Lopez-Pernas, Sonsoles
    Univ Politecn Madrid, ETSI Sistemas Informat, Dept Sistemas Informat, Madrid 28031, Spain..
    Saqr, Mohammed
    Univ Eastern Finland, Sch Comp, Joensuu 80101, Finland..
    Pears, Arnold
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Daniels, Mats
    Uppsala Univ, Dept Informat Technol, S-75105 Uppsala, Sweden..
    Malmi, Lauri
    Aalto Univ, Dept Comp Sci, Aalto 00076, Finland..
    Tedre, Matti
    Univ Eastern Finland, Sch Comp, Joensuu 80101, Finland..
    From a National Meeting to an International Conference: A Scientometric Case Study of a Finnish Computing Education Conference2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 66576-66588Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Computerisation and digitalisation are shaping the world in fundamental and unpredictable ways, which highlights the importance of computing education research (CER). As part of understanding the roots of CER, it is crucial to investigate the evolution of CER as a research discipline. In this paper we present a case study of a Finnish CER conference called Koli Calling, which was launched in 2001, and which has become a central publication venue of CER. We use data from 2001 to 2020, and investigate the evolution of Koli Calling's scholarly communities and zoom in on it's publication habits and internalisation process. We explore the narrative of the development and scholarly agenda behind changes in the conference submission categories from the perspective of some of the conference chairs over the years. We then take a qualitative perspective, analysing the conference publications based on a comprehensive bibliometric analysis. The outcomes include classification of important research clusters of authors in the community of conference contributors. Interestingly, we find traces of important events in the historical development of CER. In particular, we find clusters emerging from specific research capacity building initiatives and we can trace how these connect research spanning the world CER community from Finland to Sweden and then further to the USA, Australia and New Zealand. This paper makes a strategic contribution to the evolution of CER as a research discipline, from the perspective of one central event and publication venue, providing a broad perspective on the role of the conference in connecting research clusters and establishing an international research community. This work contributes insights to researchers in one specific CER community and how they shape the future of computing education

  • 8.
    Arfaoul, Ghada
    et al.
    Orange Labs, F-75015 Paris, France..
    Bisson, Pascal
    Thales, F-45400 Fleury Les Aubrais, France..
    Blom, Rolf
    RISE SICS, Secur Lab, S-16480 Stockholm, Sweden..
    Borgaonkar, Ravishankar
    Univ Oxford, Dept Comp Sci, Oxford OX1 2JD, England..
    Englund, Hakan
    Ericsson AB, Ericsson Res, S-16480 Stockholm, Sweden..
    Felix, Edith
    Thales, F-45400 Fleury Les Aubrais, France..
    Klaedtke, Felix
    NEC Labs Europe, D-69115 Heidelberg, Germany..
    Nakarmi, Prajwol Kumar
    Ericsson AB, Ericsson Res, S-16480 Stockholm, Sweden..
    Näslund, Mats
    KTH.
    O'Hanlon, Piers
    Univ Oxford, Dept Comp Sci, Oxford OX1 2JD, England..
    Papay, Juri
    Univ Southampton, IT Innovat Ctr, Southampton SO16 7NS, Hants, England..
    Suomalainen, Jani
    VTT Tech Res Ctr Finland, Espoo 02044, Finland..
    Surridge, Mike
    Univ Southampton, IT Innovat Ctr, Southampton SO16 7NS, Hants, England..
    Wary, Jean-Philippe
    Orange Labs, F-75015 Paris, France..
    Zahariev, Alexander
    Nixu Corp, Espoo 02150, Finland..
    A Security Architecture for 5G Networks2018Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 6, s. 22466-22479Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    5G networks will provide opportunities for the creation of new services, for new business models, and for new players to enter the mobile market. The networks will support efficient and cost-effective launch of a multitude of services, tailored for different vertical markets having varying service and security requirements, and involving a large number of actors. Key technology concepts are network slicing and network softwarization, including network function virtualization and software-defined networking. The presented security architecture builds upon concepts from the 3G and 4G security architectures but extends and enhances them to cover the new 5G environment. It comprises a toolbox for security relevant modeling of the systems, a set of security design principles, and a set of security functions and mechanisms to implement the security controls needed to achieve stated security objectives. In a smart city use case setting, we illustrate its utility; we examine the high-level security aspects stemming from the deployment of a large number of IoT devices and network softwarization.

  • 9.
    Avula, Ramana R.
    et al.
    Department of Electrification and Reliability, RISE Research Institutes of Sweden, Sweden.
    Oechtering, Tobias J.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Månsson, Daniel
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektromagnetism och fusionsfysik.
    Adversarial Inference Control in Cyber-Physical Systems: A Bayesian Approach With Application to Smart Meters2024Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 24933-24948Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With the emergence of cyber-physical systems (CPSs) in utility systems like electricity, water, and gas networks, data collection has become more prevalent. While data collection in these systems has numerous advantages, it also raises concerns about privacy as it can potentially reveal sensitive information about users. To address this issue, we propose a Bayesian approach to control the adversarial inference and mitigate the physical-layer privacy problem in CPSs. Specifically, we develop a control strategy for the worst-case scenario where an adversary has perfect knowledge of the user’s control strategy. For finite state-space problems, we derive the fixed-point Bellman’s equation for an optimal stationary strategy and discuss a few practical approaches to solve it using optimization-based control design. Addressing the computational complexity, we propose a reinforcement learning approach based on the Actor-Critic architecture. To also support smart meter privacy research, we present a publicly accessible “Co-LivEn” dataset with comprehensive electrical measurements of appliances in a co-living household. Using this dataset, we benchmark the proposed reinforcement learning approach. The results demonstrate its effectiveness in reducing privacy leakage. Our work provides valuable insights and practical solutions for managing adversarial inference in cyber-physical systems, with a particular focus on enhancing privacy in smart meter applications.

  • 10.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Network Life time Maximization for Cellular-Based M2M Networks2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, s. 18927-18940, artikkel-id 8045999Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High energy efficiency is critical for enabling massive machine-type communications (MTC) over cellular networks. This paper is devoted to energy consumption modeling, battery lifetime analysis, lifetime-aware scheduling, and transmit power control for massive MTC over cellular networks. We consider a realistic energy consumption model for MTC and model network battery-lifetime. Analytic expressions are derived to demonstrate the impact of scheduling on both the individual and network battery lifetimes. The derived expressions are subsequently employed in the uplink scheduling and transmit power control for mixed-priority MTC traffic in order to maximize the network lifetime. Besides the main solutions, low complexity solutions with limited feedback requirement are investigated, and the results are extended to existing LIE networks. In addition, the energy efficiency, spectral efficiency, and network lifetime tradeoffs in resource provisioning and scheduling for MTC over cellular networks are investigated. The simulation results show that the proposed solutions can provide substantial network lifetime improvement and network maintenance cost reduction in comparison with the existing scheduling schemes.

  • 11.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Network Lifetime Maximization for Cellular-Based M2M Networks2017Inngår i: IEEE Access, E-ISSN 2169-3536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High energy efficiency is critical for enabling massivemachine-type communications (MTC) over cellular networks.This work is devoted to energy consumption modeling,battery lifetime analysis, lifetime-aware scheduling and transmitpower control for massive MTC over cellular networks. Weconsider a realistic energy consumption model for MTC andmodel network battery-lifetime. Analytic expressions are derivedto demonstrate the impact of scheduling on both the individualand network battery lifetimes. The derived expressions aresubsequently employed in uplink scheduling and transmit powercontrol for mixed-priority MTC traffic in order to maximizethe network lifetime. Besides the main solutions, low-complexitysolutions with limited feedback requirement are investigated,and the results are extended to existing LTE networks. Also,the energy efficiency, spectral efficiency, and network lifetimetradeoffs in resource provisioning and scheduling for MTC overcellular networks are investigated. The simulation results showthat the proposed solutions can provide substantial networklifetime improvement and network maintenance cost reductionin comparison with the existing scheduling schemes.

  • 12.
    Azizi, Ali
    et al.
    Iran University of Science and Technology, Department of Electrical Engineering, Tehran, Iran.
    Jahromi, Mehdi Zareian
    Amirkabir University of Technology, Department of Electrical Engineering, Tehran, Iran.
    Dehghanian, Pooria
    Texas A&M University, Department of Electrical and Computer Engineering, College Station, TX, USA.
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Mirez, Jorge
    Universidad Nacional de Ingeniería (UNI), Group of Mathematical Modeling and Numerical Simulations, Lima, Peru.
    Sood, Vijay K.
    Ontario Tech University, Department of Electrical, Computer and Software Engineering, Oshawa, ON, Canada.
    Decentralized Multi-Objective Energy Management With Dynamic Power Electronic Converters and Demand Response Constraints2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 146297-146312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Energy management plays a pivotal role in enhancing the economic efficiency of power systems. However, it is noteworthy that a substantial number of microgrids (MGs) exhibit inherent unbalances that impose a range of critical issues, including voltage instability, elevated losses, power quality violations, safety concerns, and inefficiencies in energy management. Fast-acting power electronic converters present a relevant and efficacious solution for balancing such complex networks. This paper investigates the application of such converters within the realm of 3-phase unbalanced networks, wherein the proposed algorithm not only ameliorates network imbalances but also yields substantial reductions in operational costs, power losses, voltage deviations, and emissions. Demand response (DR) program has been applied to the model to enhance the system efficiency. The uncertainty about electric demand and renewable energy sources is considered in the simulation model for precise results. By implementing DR programs and penetrating distributed generators (DGs), the proposed model has been shown to reduce network losses and operation costs by 23% and 80%, respectively. Also, the total up-to-down voltage deviation of the voltage profile has been significantly reduced by 400%.

  • 13. Barco-Jimenez, John
    et al.
    Obando, German
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Pantoja, Andres
    Bravo, Eduardo Caicedo
    Aguado, Jose A.
    In-line Distributed Dispatch of Active and Reactive Power based on ADMM and Consensus Considering Battery Degradation in Microgrids2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 31479-31495Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents a distributed in-line strategy to manage an isolated microgrid by optimizing active and reactive power dispatch. The proposed objective function leads to minimize the operation costs and addresses some technical requirements such as diminishing power losses and voltage deviation. Additionally, the strategy deals with temporal multi-scale goals, i.e., robustness to demand disturbances and variation of renewable resources (a short-term objective), and preservation of the health of battery-based storage systems (a long-term objective). The technique uses alternating directions method of multipliers (ADMM), accelerated consensus, and a novel battery degradation model (Quadratic AH-Throughput model). We test the proposed solution in a case study that includes renewable resources and lead-acid and lithium batteries. To obtain the results of the case study, we employ a co-simulation scheme that uses Matlab and DIgSILENT. Finally, the performance of the method is compared with a centralized optimization technique.

  • 14.
    Basloom, Huda Saleh
    et al.
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21514, Saudi Arabia..
    Dahab, Mohamed Yehia
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21514, Saudi Arabia.;Agr Res Ctr ARC, Giza 12619, Egypt..
    Alghamdi, Ahmed Mohammed
    Univ Jeddah, Coll Comp Sci & Engn, Dept Software Engn, Jeddah 21493, Saudi Arabia..
    Eassa, Fathy Elbouraey
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21514, Saudi Arabia..
    Al-Ghamdi, Abdullah Saad Al-Malaise
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Informat Syst, Jeddah 21589, Saudi Arabia..
    Haridi, Seif
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Errors Classification and Static Detection Techniques for Dual-Programming Model (OpenMP and OpenACC)2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 117808-117826Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recently, incorporating more than one programming model into a system designed for high performance computing (HPC) has become a popular solution to implementing parallel systems. Since traditional programming languages, such as C, C++, and Fortran, do not support parallelism at the level of multi-core processors and accelerators, many programmers add one or more programming models to achieve parallelism and accelerate computation efficiently. These models include Open Accelerators (OpenACC) and Open Multi-Processing (OpenMP), which have recently been used with various models, including Message Passing Interface (MPI) and Compute Unified Device Architecture (CUDA). Due to the difficulty of predicting the behavior of threads, runtime errors cannot be predicted. The compiler cannot identify runtime errors such as data races, race conditions, deadlocks, or livelocks. Many studies have been conducted on the development of testing tools to detect runtime errors when using programming models, such as the combinations of OpenACC with MPI models and OpenMP with MPI. Although more applications use OpenACC and OpenMP together, no testing tools have been developed to test these applications to date. This paper presents a testing tool for detecting runtime using a static testing technique. This tool can detect actual and potential runtime errors during the integration of the OpenACC and OpenMP models into systems developed in C++. This tool implement error dependency graphs, which are proposed in this paper. Additionally, a dependency graph of the errors is provided, along with a classification of runtime errors that result from combining the two programming models mentioned earlier.

  • 15.
    Bogodorova, Tetiana
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Vanfretti, Luigi
    Model Structure Choice for a Static VAR Compensator Under Modeling Uncertainty and Incomplete Information2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, artikkel-id UNSP 22657Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To simulate the complex behavior of power systems, operators frequently rely on models. The task of model identification and validation becomes important in this context. The validity of the models has a direct influence on operator's decisions and actions. In other words, erroneous or imprecise models lead to erroneous predictions of the systems' behavior which may result in unwanted operator's actions. This paper addresses the challenge of model structure choice for modeling and parameter identification in power systems. Three types of model structures are analyzed: 1) physical principle-based modeling; 2) black-box modeling (NARX, transfer function, Hammerstein Wiener model); and 3) combination of physical and black-box modeling. This analysis has been performed using real grid measurements and available knowledge about a static VAR compensator (SVC) connected to the U.K.'s transmission network and operated by National Grid. The SVC's modeling is presented in the context of a generalized modeling and identification algorithm, that is offered as a guideline for engineers. The model validity issues of the identified SVC models that include modeling uncertainty are discussed.

  • 16.
    Bogodorova, Tetiana
    et al.
    KTH.
    Vanfretti, Luigi
    Peric, Vedran S.
    Turitsyn, Konstantin
    Identifying Uncertainty Distributions and Confidence Regions of Power Plant Parameters2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Power system operators, when obtaining a model's parameter estimates; require additional information to guide their decision on a model's acceptance. This information has to establish a relationship between the estimates and the chosen model in the parameter space. For this purpose, this paper proposes to extend the usage of the particle filter (PF) as a method for the identification of power plant parameters; and the parameters' confidence intervals, using measurements. Taking into consideration that the PF is based on the Bayesian filtering concept, the results returned by the filter contain more information about the model and its parameters than usually considered by power system operators. In this paper the samples from the multi-modal posterior distribution of the estimate are used to identify the distribution shape and associated confidence intervals of estimated parameters. Three methods [rule of thumb, least-squares cross validation, plug-in method (HSJM)] for standard deviation (bandwidth) selection of the Gaussian mixture distribution are compared with the uni-modal Gaussian distribution of the parameter estimate. The applicability of the proposed method is demonstrated using field measurements and synthetic data from simulations of a Greek power plant model. The distributions are observed for different system operation conditions that consider different types of noise. The method's applicability for model validation is also discussed.

  • 17. Bonetto, Riccardo
    et al.
    Rossi, Michele
    Tomasin, Stefano
    Fischione, Carlo
    KTH, Skolan för elektro- och systemteknik (EES), Nätverk och systemteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Joint Optimal Pricing and Electrical Efficiency Enforcement for Rational Agents in Microgrids2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, s. 19782-19798Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In electrical distribution grids, the constantly increasing number of power generation devices based on renewables demands a transition from a centralized to a distributed generation paradigm. In fact, power injection from distributed energy resources (DERs) can be selectively controlled to achieve other objectives beyond supporting loads, such as the minimization of the power losses along the distribution lines and the subsequent increase of the grid hosting capacity. However, these technical achievements are only possible if alongside electrical optimization schemes, a suitable market model is set up to promote cooperation from the end users. In contrast with the existing literature, where energy trading and electrical optimization of the grid are often treated separately, or the trading strategy is tailored to a specific electrical optimization objective, in this paper, we consider their joint optimization. We also allow for a modular approach, where the market model can support any smart grid optimization goal. Specifically, we present a multi-objective optimization problem accounting for energy trading, where: 1) DERs try to maximize their profit, resulting from selling their surplus energy; 2) the loads try to minimize their expense; and 3) the main power supplier aims at maximizing the electrical grid efficiency through a suitable discount policy. This optimization problem is proved to be non-convex, and an equivalent convex formulation is derived. Centralized solutions are discussed and a procedure to distribute the solution is proposed. Numerical results to demonstrate the effectiveness of the so obtained optimal policies are finally presented, showing the proposed model results in economic bene fits for all the users (generators and loads) and in an increased electrical efficiency for the grid.

  • 18. Cantillo-Luna, Sergio
    et al.
    Moreno-Chuquen, Ricardo
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Sood, Vijay K.
    Badsha, Shahriar
    Konstantinou, Charalambos
    Blockchain for Distributed Energy Resources Management and Integration2022Inngår i: IEEE Access, E-ISSN 2169-3536, s. 1-1Artikkel i tidsskrift (Fagfellevurdert)
  • 19. Chen, D.
    et al.
    Zhou, X.
    Li, J.
    He, J.
    Yu, X.
    Zhang, Longbin
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Qi, W.
    A Muscle Teleoperation System of a Robotic Rollator Based on Bilateral Shared Control2020Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 151160-151170, artikkel-id 9167436Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The approach that achieves the teleoperation between human muscle signals and the mobile robot is increasingly applied to transfer human muscle stiffness to enhance robotic performance. In this paper, we develop a mobile rollator control system applying a muscle teleoperation interface and a shared control method to enhance the obstacle avoidance in an effective way. In order to control intuitively, haptic feedback is utilized in the teleoperation interface and is integrated with EMG stiffness to provide a large composition force. Then the composition force is implemented with an artificial potential field method to keep the robotic rollator away from the obstacle in advance. This algorithm is superior to the traditional APF algorithm regardless of the required time and trajectory length. The experimental results demonstrate the effectiveness of the proposed muscle teleoperation system.

  • 20.
    Cheng, Lihong
    et al.
    School of Electro-Mechanical Engineering, Xidian University, Xi’an, China.
    Feng, Lei
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Mekatronik.
    Model abstraction for discrete-event systems using a SAT solver2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 17334-17347Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Model abstraction for finite state automata is beneficial to reduce the complexity of discrete-event systems (DES), enhances the readability and facilitates the control synthesis and verification of DES. Supremal quasi-congruence computation is an effective way for reducing the state space of DES. Effective algorithms on the supremal quasi-congruence relation have been developed based on the graph theory. This paper proposes a new approach to translate the supremal quasi-congruence computation into a satisfiability (SAT) problem that determines whether there exists an assignment for Boolean variables in the state-to-coset allocation matrix. If the result is satisfied, then the supremal quasi-congruence relation exists and the minimum equivalence classes is obtained. Otherwise, it indicates that there is no such supremal quasi-congruence relation, and a new set of observable events needs to be modified or reselected for the original system model. The satisfiability problem on the computation of supremal quasi-congruence relation is solved by different methods, which are respectively implemented by mixed integer linear programming (MILP) in MATLAB, binary linear programming (BLP) in CPLEX, and a SAT-based solver (Z3Py). Compared with the MILP and BLP methods, the SAT method is more efficient and stable. The computation time of model abstraction for large-scale systems by Z3Py solver is significantly reduced.

  • 21.
    Chomtong, P.
    et al.
    King Mongkuts Univ Technol North Bangkok, Fac Tech Educ, Dept Teacher Training Elect Engn, Bangkok 10140, Thailand..
    Krachodnok, P.
    Suranaree Univ Technol, Inst Engn, Sch Telecommun Engn, Nakhon Ratchasima 30000, Thailand..
    Konpang, J.
    Rajamangala Univ Technol Krungthep, Fac Engn, Dept Elect & Telecommun Engn, Bangkok 10120, Thailand..
    Somjit, Nutapong
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik. Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England.; Chiang Mai Univ, Fac Engn, Dept Elect Engn, Chiang Mai 50200, Thailand..
    Mahatthanajatuphat, C.
    King Mongkuts Univ Technol North Bangkok, Fac Engn, Dept Elect & Comp Engn, Bangkok 10140, Thailand..
    Akkaraekthalin, P.
    King Mongkuts Univ Technol North Bangkok, Fac Engn, Dept Elect & Comp Engn, Bangkok 10140, Thailand..
    Miniaturized Multiband EBG Reflector Using DICPW Structure for Wireless Communication Systems2024Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 30398-30415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wireless communication technology evolves to meet current needs, focusing on antenna size reduction for smaller, multi-frequency devices. This research introduces a novel approach to miniaturizing a multiband Electromagnetic Band Gap (EBG) reflector using a Double Interdigitated Coplanar Waveguide (DICPW) structure. The mushroom-patterned EBG unit cell, employing a double interdigital technique based on a Coplanar Waveguide (CPW), achieves a significantly slower wave on the transmission line. The unit cell size can be reduced from lambda/2 to lambda /8, allowing control over the second to fourth resonance frequencies. Engineered for a fundamental frequency of 1.8 GHz (LTE), the proposed EBG unit cell supports frequency ranges of 2.45 GHz (WLAN), 4.3 GHz (Altimeter), and 5.2 GHz (WLAN). Integrating this EBG reflector with a dipole antenna at the same frequency results in directional radiation patterns and gains of 8.29 dBi, 8.76 dBi, 8.55 dBi, and 8.22 dBi at resonance frequencies. The innovative reflector, with improved gain and compact dimensions, is relevant to cube satellite and wireless communication systems with versatile multiband frequency requirements.

  • 22.
    Chomtong, P.
    et al.
    King Mongkuts Univ Technol North Bangkok, Fac Tech Educ, Dept Teacher Training Elect Engn, Bangkok 10800, Thailand..
    Krachodnok, P.
    Suranaree Univ Technol, Inst Engn, Sch Telecommun Engn, Nakhon Ratchasima 30000, Thailand..
    Mahatthanajatuphat, C.
    King Mongkuts Univ Technol North Bangkok, Fac Engn, Dept Elect & Comp Engn, Bangkok 10800, Thailand..
    Somjit, Nutapong
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik. Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England; Chiang Mai Univ, Fac Engn, Dept Elect Engn, Chiang Mai 50200, Thailand..
    Akkaraekthalin, P.
    King Mongkuts Univ Technol North Bangkok, Fac Engn, Dept Elect & Comp Engn, Bangkok 10800, Thailand..
    Dual-Mode Characteristic Based on Miniaturized Metamaterial for Multiband Operation Utilizing Double-Layer Interdigital and Trisection Step-Impedance Techniques2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 126232-126250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a dual-mode characteristic for miniaturized metamaterial with a unit cell design based on an interdigital coplanar waveguide (ICPW) combined with trisection step-impedance to enable the three resonant frequency responses of 1.8 GHz, 3.7 GHz, and 5.8 Hz. In addition, the unit cell dimensions can be reduced from 2/2 to 2/8 due to the fact that the ICPW technique based on the CPW structure enhances the capacitive load between the transmission line and the side ground, thereby increasing the slow-wave on the transmission line. In addition, the trisection step-impedance will be incorporated and applied to the transmission line and cooperate with the unit cell structure's capacitive load to effectively resonate at the desired frequency location. Moreover, the unit cell structure designed with the method above must be utilized as a double layer in which the structure on both sides is identical. The back structure will property the rod, which will cause the permittivity and permeability to be negative and closer to zero. This property of the proposed material allows for its utilization as a director at its first resonant frequency and as a reflector at the subsequent second and third resonant frequencies. The proposed metamaterial employs FR-4 printed circuit boards with a dielectric constant (epsilon(r)) of 4.4, a substrate thickness of 1.6 mm, a conductor thickness of 0.035 mm, and a loss tangent (tan delta) of 0.04. The unit cell size is approximately 14 mmx14 mm. The unit cell will then be arranged as a 7 x 7 array with an overall dimension of 98 x 98 mm(2) to evaluate an antenna's performance. An antenna used for testing the proposed unit cell is a dipole antenna that propagates at a single frequency corresponding to the unit cell's resonant frequency. At all resonant frequencies, the impedance matching of the dipole is less than -10 dB. At 1.8 GHz, 3.7 GHz, and 5.8 GHz, the dipole antenna gain is 2 dBi, 2.06 dBi, and 1.95 dBi, respectively. Moreover, the dipole antenna's characteristics were simulated using the CST program in conjunction with the unit cell array. Based on the simulation and measurement results, the antenna with the unit cell array exhibits an impedance bandwidth of less than -10 dB at frequencies of 1.8, 3.7, and 5.8 GHz. The gains obtained from the simulation results are 5.49 dBi, 8.21 dBi, and 7.87 dBi, while the measurement results show gains of 5.73 dBi, 8.19 dBi, and 7.79 dBi, respectively. The simulated and measured outcomes demonstrate a substantial correspondence.

  • 23.
    Chomtong, P.
    et al.
    King Mongkut's University of Technology North Bangkok, Faculty of Technical Education, Department of Teacher Training in Electrical Engineering, Bangkok, Thailand.
    Somjit, Nutapong
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik. School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT Leeds, U.K; Chiang Mai University, Muang, Faculty of Engineering, Department of Electrical Engineering, Chiang Mai, Thailand.
    Krachodnok, P.
    Institute of Engineering, Suranaree University of Technology, School of Telecommunication Engineering, Nakhon Ratchasima, Thailand.
    Mahatthanajatuphat, C.
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    Tawatchai, S.
    Aeronautical Electronics Engineering from Civil Aviation Training Center (CATC), Bangkok, Thailand.
    Akkaraekthalin, P.
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    A Miniaturized Multiband FSS Director Using Double Layer With ICPW Technique Structure for Wireless Communication Systems2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 81527-81544Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a multiband director based on the frequency selective surface (FSS) unit cell structure using the double layer with interdigital CPW (ICPW) technique. The unit cell consists of the front and the back. The front part has been designed using an ICPW technique based on a coplanar waveguide structure to enhance the capacitance between the transmission line and the semi-ground. The overall structural dimension of the unit cell can be designed to be smaller than the conventional range of λ/2 to λ/8, due to the influence of the slow wave effect on the capacitance of the structure. The back part is the inverted layer of the front, which alternates between substrate and copper. It is composed of a square loop resonator with a double meandering line. The capacitance generated by a double meander line enhances the capacitance in the front part, which influences the control of all resonant frequencies and increases the slow wave on the double-layer unit cell structure, resulting in a significantly reduced dimension. The resonance frequencies for the designs are 1.8 GHz (LTE), 3.7 GHz (Wi-MAX) and 5.2 GHz (WLAN), respectively. According to simulation results, the FSS can transmit all resonant frequencies. It has an overall dimension of 10.93 mm × 11.48 mm. In addition, the FSS unit cell has been arranged as a 7 × 7 array for use as a director. The dimensions are 73.48 mm × 77.38 mm. The FSS director will be evaluated utilizing an omnidirectional dipole antenna at the same resonant frequency as the FSS unit cell. According to both the simulated and measured outcomes, the impedance matching value is below -10 dB at the three resonant frequencies. The FSS director equipped with a dipole antenna exhibits bidirectional propagation characteristics across all resonant frequencies. The antenna gains for simulation are 3.45 dBi, 3.05 dBi, and 3.72 dBi, while the antenna gains for measurement are 3.05 dBi, 2.98 dBi, and 3.12 dBi. The findings indicate a high level of concurrence.

  • 24.
    Chudpooti, Nonchanutt
    et al.
    King Mongkut's University of Technology North Bangkok, Faculty of Applied Science, Department of Industrial Physics and Medical Instrumentation, Bangkok, Thailand.
    Sangpet, Patchadaporn
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    Pechrkool, Tanaporn
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    Duangrit, Nattapong
    National Astronomical Research Institute of Thailand (Public Organization), Centre of Observatory Operations and Engineering (COOE), Division for Radio Observatories Operations and Engineering (CROE), Chiang Mai, Thailand.
    Thaiwirot, Wanwisa
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    Akkaraekthalin, Prayoot
    King Mongkut's University of Technology North Bangkok, Faculty of Engineering, Department of Electrical and Computer Engineering, Bangkok, Thailand.
    Somjit, Nutapong
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik. School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT Leeds, U.K; Chiang Mai University, Muang, Faculty of Engineering, Department of Electrical Engineering, Chiang Mai, Thailand.
    An Additive 3D-Printed Hemispherical Lens With Flower-Shaped Stub Slot Ultra-Wideband Antenna for High-Gain Radiation2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 91225-91233Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a 3D-printed hemispherical lens integrated with a planar ultra-wideband (UWB) antenna. The flower-shaped stub slot UWB antenna is made of 0.8-mm FR-4. The operating frequency of the UWB covers 3.10 GHz - 11.6 GHz with a nominal gain at zero degrees of 1.74 dBi. To enhance the UWB antenna's high-gain radiation, a 3D-printed additive hemispherical lens is designed and fabricated from acrylonitrile butadiene styrene (ABS). The electrical properties, i.e., relative permittivity and loss tangent, of ABS are 2.66, and 0.003, respectively. Four different lens radii (8 mm, 10 mm, 12 mm, and 14 mm) are chosen to investigate the gain of the antenna. In all four cases, the 3D-printed lens is fixed in place in front of the UWB antenna with an optimum gap of 3 mm chosen to reduce the wave reflection between the lens and source antenna. Based on the measurement results, the reflection coefficient, S11, of four conditions still covers the UWB frequency range. The nominal gain at zero-degree values for lens radii of 8 mm, 10 mm, 12 mm, and 14 mm are 3.43 dBi, 4.22 dBi, 4.73 dBi, and 5.18 dBi, respectively. The proposed additive 3D-printed dielectric lens antenna also offers many advantages, i.e., ease of design and assembly, low-cost fabrication, and size reduction for high-gain antennas. Furthermore, the high-gain antenna provides a narrow half power beamwidth, which can be implemented to increase the resolution of the imaging system.

  • 25.
    Ciftci, Baris
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Gross, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Augustin, Tim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Wang, Xiongfei
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Nee, Hans-Peter
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Wireless Communication in Modular Multilevel Converters and Electromagnetic Interference Characterization2022Inngår i: IEEE Access, E-ISSN 2169-3536, s. 38189-38201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The wireless control of modular multilevel converter (MMC) submodules was recently proposed. The success of the control depends on specialized control methods suitable for wireless communication and a properly designed wireless communication network in the MMC valve hall while aiming for low latency and high reliability. The wireless communication in the hall can be affected by the electromagnetic interference (EMI) of MMC submodules, voltage and current transients. In this article, firstly, a wireless communication network based on 5G New Radio is designed for an example full-scale MMC valve hall. After that, the radiated EMI characteristics of the MMC submodules with different voltage and current ratings and two dc circuit breakers are measured. The effects of EMI on wireless communication in the multi-GHz frequency band are tested. The interference from the components is confined below 500 MHz, and the wireless communication with 5825 MHz center frequency is not affected by the interference.

    Fulltekst (pdf)
    fulltext
  • 26.
    de Giorgio, Andrea
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Artificial intelligence control in 4D cylindrical space for industrial robotic applications2020Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 174833-174844Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper argues that an efficient artificial intelligence control algorithm needs the built-in symmetries of an industrial robot manipulator to be further characterized and exploited. The product of this enhancement is a four-dimensional (4D) discrete cylindrical grid space that can directly replace complex robot models. A* is chosen for its wide use among such algorithms to study the advantages and disadvantages of steering the robot manipulator within the 4D cylindrical discrete grid. The study shows that this approach makes it possible to control a robot without any specific knowledge of the robot kinematic and dynamic models at planning and execution time. In fact, the robot joint positions for each grid cell are pre-calculated and stored as knowledge, then quickly retrieved by the pathfinding algorithm when needed. The 4D cylindrical discrete space has both the advantages of the configuration space and the three-dimensional Cartesian workspace of the robot. Since path optimization is the core of any search algorithms, including A*, the 4D cylindrical grid provides for a search space that can embed further knowledge in form of cell properties, including the presence of obstacles and volumetric occupancy of the entire industrial robot body for obstacle avoidance applications. The main trade-off is between a limited capacity for pre-computed grid knowledge and the path search speed. This innovative approach encourages the use of search algorithms for industrial robotic applications, opens up to the study of other robot symmetries present in different robot models and lays a foundation for the application of dynamic obstacle avoidance algorithms.

    Fulltekst (pdf)
    fulltext
  • 27.
    Della Penda, Demia
    et al.
    Ericsson AB, S-16480 Kista, Sweden..
    Abrardo, Andrea
    Univ Siena, Dept Informat Engn, I-53100 Siena, Italy.;Consorzio Nazl Interuniv Telecomunicaz, I-43124 Parma, Italy..
    Moretti, Marco
    Consorzio Nazl Interuniv Telecomunicaz, I-43124 Parma, Italy.;Univ Pisa, Dept Informat Engn, I-56122 Pisa, Italy..
    Johansson, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Reglerteknik.
    Distributed Channel Allocation for D2D-Enabled 5G Networks Using Potential Games2019Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 11195-11208Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Frequency channel allocation is a key technique for improving the performance of cellular networks. In this paper, we address the channel allocation problem for a 5G multi-cell system. We consider a heterogeneous network in which cellular users, micro-cell users, and device-to-device (D2D) communications coexist within the radio footprint of the macro cell. We maximize the aggregate transmission rate, exploiting channel diversity and managing both the inter-cell interference, typical of cellular networks and the intra-cell interference generated by the nonorthogonal transmissions of the small-cell and D2D users. By modeling the allocation problem as a potential game, whose Nash equilibria correspond to the local optima of the objective function, we propose a new decentralized solution. The convergence of our scheme is enforced by using a better response dynamic based on a message passing approach. The simulation results assess the validity of the proposed scheme in terms of convergence time and achievable rate under different settings.

  • 28.
    D’Orto, Manolo
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Sjöblom, Svante
    Chien, Lung Sheng
    Axner, Lilit
    ENCCS, Uppsala University.
    Gong, Jing
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, Parallelldatorcentrum, PDC.
    Comparing Different Approaches for Solving Large Scale Power-flow Problems with the Newton-Raphson Method2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 56604-56615Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper focuses on using the Newton-Raphson method to solve the power-flow problems. Since the most computationally demanding part of the Newton-Raphson method is to solve the linear equations at each iteration, this study investigates different approaches to solve the linear equations on both central processing unit (CPU) and graphical processing unit (GPU). Six different approaches have been developed and evaluated in this paper: two approaches of these run entirely on CPU while other two of these run entirely on GPU, and the remaining two are hybrid approaches that run on both CPU and GPU. All six direct linear solvers use either LU or QR factorization to solve the linear equations. Two different hardware platforms have been used to conduct the experiments. The performance results show that the CPU version with LU factorization gives better performance compared to the GPU version using standard library called cuSOLVER even for the larger power-flow problems. Moreover, it has been proven that the best performance is achieved using a hybrid method where the Jacobian matrix is assembled on GPU, the preprocessing with a sparse high performance linear solver called KLU is performed on the CPU in the first iteration, and the linear equation is factorized on the GPU and solved on the CPU. Maximum speed up in this study is obtained on the largest case with 25000 buses. The hybrid version shows a speedup factor of 9.6 with a NVIDIA P100 GPU while 13.1 with a NVIDIA V100 GPU in comparison with baseline CPU version on an Intel Xeon Gold 6132 CPU.

  • 29.
    Eassa, Fathy Elbouraey
    et al.
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Alghamdi, Ahmed Mohammed
    Univ Jeddah, Coll Comp Sci & Engn, Dept Software Engn, Jeddah 21493, Saudi Arabia..
    Haridi, Seif
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Khemakhem, Maher Ali
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Al-Ghamdi, Abdullah S. Al-Malaise
    King Abdulaziz Univ, Fac Comp & Informat Technol, Dept Informat Syst, Jeddah 21589, Saudi Arabia..
    Alsolami, Eesa A.
    Univ Jeddah, Coll Comp Sci & Engn, Dept Cybersecur, Jeddah 21493, Saudi Arabia..
    ACC_TEST: Hybrid Testing Approach for OpenACC-Based Programs2020Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 80358-80368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years, OpenACC has been used in many supercomputers and attracted many non-computer science specialists for parallelizing their programs in different scientific fields, including weather forecasting and simulations. OpenACC is a high-level programming model that supports parallelism and is easy to learn to use by adding high-level directives without considering too many low-level details. Testing parallel programs is a difficult task, made even harder if using programming models, especially if they have been badly programmed. If so, it will be challenging to detect their runtime errors as well as their causes, whether the error is from the user source code or from the programming model directives. Even when these errors are detected and the source code modified, we cannot guarantee that the errors have been corrected or are still hidden. There are many tools and studies that have investigated several programming models for identifying and detecting related errors. However, OpenACC has not been targeted clearly in any testing tool or previous studies, even though OpenACC has many benefits and features that could lead to increasing use in achieving parallel systems with less effort. In this paper, we enhance ACC_TEST with the ability to test OpenACC-based programs and detect runtime errors by using hybrid-testing techniques that enhance error coverage occurring in OpenACC as well as overheads and testing time.

  • 30.
    Emadeddin, Ahmad
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektromagnetism och fusionsfysik.
    Jonsson, B. Lars G.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektromagnetism och fusionsfysik.
    A Fully Integrated Filtering Vivaldi Antenna With High Selectivity and Wide Out-of-Band Suppression2024Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 2690-2700Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper introduces a novel filtering approach that employs integrated periodic structures with a conventional Vivaldi antenna to achieve a fully integrated bandpass filtering antenna. The approach results in a wide out-of-band suppression, high passband selectivity, adjustable operational bandwidth, and low insertion loss. The proposed filtering approach maintains the original size of the conventional Vivaldi antenna (base antenna) without requiring additional modifications. To validate the approach, we present two filtering Vivaldi antennas: filtering antenna I (center frequency: 18GHz, fractional bandwidth: 21%, insertion loss: 0.32dB) and filtering antenna II (center frequency: 6.5GHz, fractional bandwidth: 12%, insertion loss: 0.6dB). Their wide out-of-band gain suppression (typically >= 15dB) covers the conventional Vivaldi antenna's frequency range (4-24GHz). A prototype of the filtering antenna I is manufactured. Its measurement results validate the proposed approach and show good agreement with the simulated reflection coefficient, realized gain, and radiation patterns. The features of the proposed filtering antenna approach, make it suitable for various applications requiring efficient frequency filtering.

  • 31.
    Falk Olson, Gustaf
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Wu, Yixuan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Ikram Ul Haq, Omer
    ABB Corporate Research, Västerås, Sweden.
    Peretti, Luca
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Enabling Variable Phase-Pole Drives with the Harmonic Plane Decomposition2024Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 40049-40063Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Magnet-free variable phase-pole machines are competitive alternatives in electric vehicles where torque-speed operating region, reliability, cost, and energy efficiency are key metrics. However, their modeling and control have so far relied on existing fixed-phase and pole-symmetrical models, limiting their drive capabilities especially when switching the number of poles on the fly. This paper establishes the harmonic plane decomposition theory as a space-discrete Fourier transformation interpretation of the Clarke transformation, decomposing all pole-pair fields into a fixed number of orthogonal subspaces with invariant parameters. The model remains unaltered for all phase-pole configurations, guaranteeing continuity even under phase-pole transitions. Relations of the state and input space vectors, and model parameters to those of the vector space decomposition theory used for multiphase machines are established via the use of the complex winding factor. Experiments confirm the modeling theory and demonstrate its practical usefulness by performing a field-oriented-controlled phase-pole transition. Non-trivial configurations with more than one slot/pole/phase and a fractional phase number are also demonstrated.

    Fulltekst (pdf)
    fulltext
  • 32. Fawad,
    et al.
    Khan, Muhammad Jamil
    Riaz, Muhammad Ali
    Shahid, Humayun
    Khan, Mansoor Shaukat
    Amin, Yasar
    Loo, Jonathan
    Tenhunen, Hannu
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system, Integrerade komponenter och kretsar.
    Texture Representation Through Overlapped Multi-Oriented Tri-Scale Local Binary Pattern2019Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 66668-66679Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper ideates a novel texture descriptor that retains its classification accuracy under varying conditions of image orientation, scale, and illumination. The proposed Overlapped Multi-oriented Tri-scale Local Binary Pattern (OMTLBP) texture descriptor also remains insensitive to additive white Gaussian noise. The wavelet decomposition stage of the OMTLBP provides robustness to photometric variations, while the two subsequent stages - overlapped multi-oriented fusion and multi-scale fusion - provide resilience against geometric transformations within an image. Isolated encoding of constituent pixels along each scale in the joint histogram enables the proposed descriptor to capture both micro and macro structures within the texture. Performance of the OMTLBP is evaluated by classifying a variety of textured images belonging to Outex, KTH-TIPS, Brodatz, CUReT, and UIUC datasets. The experimental results validate the superiority of the proposed method in terms of classification accuracy when compared with the state-of-the-art texture descriptors for noisy images.

  • 33.
    Flatken, Markus
    et al.
    Institute for Software Technology (SC), Software for Space Systems and Interactive Visualization, German Aerospace Center (DLR), Braunschweig, Germany.
    Podobas, Artur
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Chien, Wei Der
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Beräkningsvetenskap och beräkningsteknik (CST).
    Markidis, Stefano
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Beräkningsvetenskap och beräkningsteknik (CST).
    Gerndt, Andreas
    Institute for Software Technology (SC), Software for Space Systems and Interactive Visualization, German Aerospace Center (DLR), Braunschweig, Germany.
    et al.,
    VESTEC: Visual Exploration and Sampling Toolkit for Extreme Computing2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 87805-87834Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Natural disasters and epidemics are unfortunate recurring events that lead to huge societal and economic loss. Recent advances in supercomputing can facilitate simulations of such scenarios in (or even ahead of) real-time, therefore supporting the design of adequate responses by public authorities. By incorporating high-velocity data from sensors and modern high-performance computing systems, ensembles of simulations and advanced analysis enable urgent decision-makers to better monitor the disaster and to employ necessary actions (e.g., to evacuate populated areas) for mitigating these events. Unfortunately, frameworks to support such versatile and complex workflows for urgent decision-making are only rarely available and often lack in functionalities. This paper gives an overview of the VESTEC project and framework, which unifies orchestration, simulation, in-situ data analysis, and visualization of natural disasters that can be driven by external sensor data or interactive intervention by the user. We show how different components interact and work together in VESTEC and describe implementation details. To disseminate our experience three different types of disasters are evaluated: a Wildfire in La Jonquera (Spain), a Mosquito-Borne disease in two regions of Italy, and the magnetic reconnection in the Earth magnetosphere.

  • 34.
    Fodor, Gábor
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. Ericsson Research, Sweden.
    Parkvall, S.
    Sorrentino, S.
    Wallentin, P.
    Lu, Q.
    Brahmi, N.
    Device-to-device communications for national security and public safety2014Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 2, s. 1510-1520, artikkel-id 6985517Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Device-to-device (D2D) communications have been proposed as an underlay to long-term evolution (LTE) networks as a means of harvesting the proximity, reuse, and hop gains. However, D2D communications can also serve as a technology component for providing public protection and disaster relief (PPDR) and national security and public safety (NSPS) services. In the United States, for example, spectrum has been reserved in the 700-MHz band for an LTE-based public safety network. The key requirement for the evolving broadband PPDR and NSPS services capable systems is to provide access to cellular services when the infrastructure is available and to efficiently support local services even if a subset or all of the network nodes become dysfunctional due to public disaster or emergency situations. This paper reviews some of the key requirements, technology challenges, and solution approaches that must be in place in order to enable LTE networks and, in particular, D2D communications, to meet PPDR and NSPS-related requirements. In particular, we propose a clustering-procedure-based approach to the design of a system that integrates cellular and ad hoc operation modes depending on the availability of infrastructure nodes. System simulations demonstrate the viability of the proposed design. The proposed scheme is currently considered as a technology component of the evolving 5G concept developed by the European 5G research project METIS.

  • 35.
    Fodor, Gábor
    et al.
    Ericsson Research, Sweden.
    Roger, Sandra
    Rajatheva, Nandana
    Ben Slimane, Slimane
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Svensson, Tommy
    Popovski, Petar
    B. da Silva Jr., Jose Mairton
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Ali, Samad
    An Overview of Device-to-Device Communications Technology Components in METIS2016Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 4, s. 3288-3299Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the standardization of network-assisted deviceto-device (D2D) communications by the 3 rd Generation Partnership Project progresses, the research community has started to explore the technology potential of new advanced features that will largely impact the performance of 5G networks. For 5G, D2D is becoming an integrative term of emerging technologies that take advantage of the proximity of communicating entities in licensed and unlicensed spectra. The European 5G research project Mobile and Wireless Communication Enablers for the 2020 Information Society (METIS) has identified advanced D2D as a key enabler for a variety of 5G services, including cellular coverage extension, social proximity and communicating vehicles. In this paper, we review the METIS D2D technology components in three key areas of proximal communications – network-assisted multi-hop, full-duplex, and multi-antenna D2D communications – and argue that the advantages of properly combining cellular and ad hoc technologies help to meet the challenges of the information society beyond 2020.

  • 36. Gautam, Sumit
    et al.
    Kumar, Sumit
    Chatzinotas, Symeon
    Ottersten, Björn
    Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Esch-sur-Alzette, Luxembourg.
    Experimental evaluation of RF waveform designs for Wireless Power Transfer using Software Defined Radio2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 132609-132622Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility to harvest energy from ambient radio-frequency (RF) sources has intrigued humankind for the past several decades. In this context, there has been a tremendously growing research interest in the field of wireless power transfer (WPT) using the RF range of the electromagnetic (EM) spectrum. In this paper, we experimentally investigate the aspect of real-time energy harvesting (EH) via different types of waveform designs such as orthogonal frequency division multiplexing (OFDM), square, triangular, sinusoidal, and sawtooth. We make use of a Software Defined Radio (SDR) and a Powercast P21XXCSR-EVB EH module to carry out the experiments on a practical device to assess performance. Specifically, we are interested in obtaining some insights based on the comparison between the aforementioned waveform designs from the perspectives of the separation distance between the USRP and P21XXCSR-EVB EH module, and power emission via USRP. In this vein, we perform additional subsequent experiments after reporting the practical effectiveness of the OFDM waveform, which also follows our intuitive analysis. Correspondingly, we study the effect on WPT with variable USRP transmit power, the separation distance between the USRP and EH antennas, number of OFDM sub-carriers, and multipath setting. As an application of OFDM, the effectiveness of fifth generation-new radio (5G-NR) and long-term evolution (LTE) waveforms are also tested for the WPT mechanism. The demonstration of the EH is provided in terms of the above-mentioned investigation metrics while seeking the best waveform to support WPT. 

  • 37.
    Geraci, Giovanni
    et al.
    Univ Pompeu Fabra, Dept Informat & Commun Technol, Barcelona 08018, Spain..
    Garcia-Rodriguez, Adrian
    Nokia Bell Labs, Dublin D15 Y6NT, Ireland..
    Giordano, Lorenzo Galati
    Nokia Bell Labs, Dublin D15 Y6NT, Ireland..
    Lopez-Perez, David
    Nokia Bell Labs, Dublin D15 Y6NT, Ireland..
    Björnson, Emil
    Linköping Univ, Dept Elect Engn, S-58183 Linköping, Sweden..
    Understanding UAV Cellular Communications: From Existing Networks to Massive MIMO2018Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 6, s. 67853-67865Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to bestow the reader with a timely study of UAV cellular communications, bridging the gap between the 3GPP standardization status quo and the more forward-looking research. Special emphasis is placed on the downlink command and control (C&C) channel to aerial users, whose reliability is deemed of paramount technological importance for the commercial success of UAV cellular communications. Through a realistic side-by-side comparison of two network deployments - a present-day cellular infrastructure versus a next-generation massive MIMO system - a plurality of key facts are cast light upon, with the three main ones summarized as follows: 1) UAV cell selection is essentially driven by the secondary lobes of a base station's radiation pattern, causing UAVs to associate to far-flung cells; 2) over a 10 MHz bandwidth, and for UAV heights of up to 300 m, massive MIMO networks can support 100 kbps C&C channels in 74% of the cases when the uplink pilots for channel estimation are reused among base station sites, and in 96% of the cases without pilot reuse across the network; and 3) supporting UAV C&C channels can considerably affect the performance of ground users on account of severe pilot contamination, unless suitable power control policies are in place.

  • 38.
    Getman, Yaroslav
    et al.
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Phan, Nhan
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Al-Ghezi, Ragheb
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Voskoboinik, Ekaterina
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Singh, Mittul
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland.;Silo AI, Helsinki 00180, Finland..
    Grosz, Tamas
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Kurimo, Mikko
    Aalto Univ, Dept Informat & Commun Engn, Espoo 02150, Finland..
    Salvi, Giampiero
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH. Norwegian Univ Sci & Technol, Dept Signal Proc, N-7034 Trondheim, Norway.;KTH Royal Inst Technol, EECS, S-11428 Stockholm, Sweden..
    Svendsen, Torbjorn
    Norwegian Univ Sci & Technol, Dept Signal Proc, N-7034 Trondheim, Norway..
    Strombergsson, Sofia
    Karolinska Inst, Dept Clin Sci Intervent & Technol, S-14152 Huddinge, Sweden..
    Smolander, Anna
    Tampere Univ, Fac Social Sci, Logoped, Welf Sci, Tampere 33100, Finland..
    Ylinen, Sari
    Tampere Univ, Fac Social Sci, Logoped, Welf Sci, Tampere 33100, Finland..
    Developing an AI-Assisted Low-Resource Spoken Language Learning App for Children2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 86025-86037Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Computer-assisted Language Learning (CALL) is a rapidly developing area accelerated by advancements in the field of AI. A well-designed and reliable CALL system allows students to practice language skills, like pronunciation, any time outside of the classroom. Furthermore, gamification via mobile applications has shown encouraging results on learning outcomes and motivates young users to practice more and perceive language learning as a positive experience. In this work, we adapt the latest speech recognition technology to be a part of an online pronunciation training system for small children. As part of our gamified mobile application, our models will assess the pronunciation quality of young Swedish children diagnosed with Speech Sound Disorder, and participating in speech therapy. Additionally, the models provide feedback to young non-native children learning to pronounce Swedish and Finnish words. Our experiments revealed that these new models fit into an online game as they function as speech recognizers and pronunciation evaluators simultaneously. To make our systems more trustworthy and explainable, we investigated whether the combination of modern input attribution algorithms and time-aligned transcripts can explain the decisions made by the models, give us insights into how the models work and provide a tool to develop more reliable solutions.

  • 39.
    Gevari, Moein Talebian
    et al.
    Uppsala Univ, Dept Elect Engn, Div Solid State Elect, Angstrom Lab, S-75237 Uppsala, Sweden.;Sabanci Univ, Fac Engn & Nat Sci, TR-34956 Istanbul, Turkey.;Sabanci Univ, Nanotechnol Res & Applicat Ctr, TR-34956 Istanbul, Turkey..
    Aydemir, Gizem
    Sorbonne Univ, Inst Intelligent Syst & Robot ISIR, F-75005 Paris, France.;Yildiz Tech Univ, Dept Mechatron Engn, TR-34349 Istanbul, Turkey..
    Gharib, Ghazaleh
    Sabanci Univ, Fac Engn & Nat Sci, TR-34956 Istanbul, Turkey.;Sabanci Univ, Nanotechnol Res & Applicat Ctr, TR-34956 Istanbul, Turkey..
    Kutlu, Ozlem
    Sabanci Univ, Fac Engn & Nat Sci, TR-34956 Istanbul, Turkey..
    Uvet, Huseyin
    Yildiz Tech Univ, Dept Mechatron Engn, TR-34349 Istanbul, Turkey..
    Ghorbani, Morteza
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning. Sabanci Univ, Nanotechnol Res & Applicat Ctr, TR-34956 Istanbul, Turkey.;Sabanci Univ, Ctr Excellence Funct Surfaces & Interfaces Nano D, TR-34956 Istanbul, Turkey..
    Kosar, Ali
    Uppsala Univ, Dept Elect Engn, Div Solid State Elect, Angstrom Lab, S-75237 Uppsala, Sweden.;Sabanci Univ, Fac Engn & Nat Sci, TR-34956 Istanbul, Turkey.;Sabanci Univ, Ctr Excellence Funct Surfaces & Interfaces Nano D, TR-34956 Istanbul, Turkey..
    Local Carpet Bombardment of Immobilized Cancer Cells With Hydrodynamic Cavitation2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 14983-14991Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presents a method based on carpet bombardment of immobilized cells with cavitating flows. For this, immobilized cancer cell lines are exposed to micro scale cavitating flows from the tip of a micro nozzle under the effect of cavitation microbubbles. The deformation as a result of cavitation bubbles on exposed cells differs from one cell type to another. Therefore, the difference in cell deformation upon cavitation exposure (carpet bombardment) acts as a valuable indicator for cancer diagnosis. The developed system is tested on HCT-116 (Human Colorectal Carcinoma), MDA-MB-231 (Breast Adenocarcinoma), ONCO-DG-1 (Ovarian Adenocarcinoma) cell lines due to their clinical importance. The mechanical effects of cavitation are examined by considering the single-cell lysis effect (the cell membrane is ruptured, and the cell is destroyed) with the help of the Scanning Electron Microscopy (SEM) technique. Our study proposes a promising label-free method for the potential use in cancer diagnosis with cavitation bubble collapse, where microbubbles could be precisely controlled and directed to the desired locations, as well as the characterization of the biophysical properties of cancer cells. The proposed approach tool has the advantages of label-free approach, simple structure and low cost and is a substantial alternative for the existing tools.

  • 40.
    Ghasemifard, Fatemeh
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Analyzing Glide-Symmetric Holey Metasurfaces Using a Generalized Floquet Theorem2018Inngår i: IEEE Access, E-ISSN 2169-3536Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Ghorbani, Morteza
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning. Sabanci Univ, Nanotechnol Res & Applicat Ctr, TR-34956 Istanbul, Turkey.;Sabanci Univ, Ctr Excellence Funct Surfaces & Interfaces Nanodi, TR-34956 Istanbul, Turkey..
    The Hydrodynamic Cavitation Manifestation in Small Chips2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 110517-110524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cavitation is a phase change phenomenon generated by the static pressure reduction of a liquid medium at a constant temperature. This process has been considered as a disadvantageous mechanism in most turbomachinery systems, however, its potential in releasing energy at the bubble collapse stage has received lots of attention in recent decades. Particularly, the applicability of this phenomenon in micro scale gives rise to the research studies in different fields, i.e., wastewater treatment and medical imaging. In this study, microfluidic devices housing small microchannels have been fabricated to study the generation of the cavitating flow patterns bubbles. The main focuses in this work are on the surface and side wall roughness together with the size reduction effects on cavitation bubble generation. Accordingly, the microfluidic devices were fabricated using the techniques adopted from semiconductor based micro- fabrication. The experiments were performed at relatively higher upstream pressure, 4 to 7 MPa, to investigate the durability of the devices and flow patterns features. The results show that the side wall roughness elements are very effective in the small microchannels in terms of facile cavitating flow generation, while the size reduction in the diameter of the channel does not lead to intensified cavitating flow necessarily. The results show that the cavitation bubbles extended to the outlet of the side wall roughened microchannel even at the upstream pressure of 5.5 MPa, while the supercavitation flow regime was observed at high upstream pressure of 7 MPa.

  • 42.
    Goli, Zahra
    et al.
    Iran Univ Sci & Technol IUST, Sch Elect Engn, Tehran 1684613114, Iran..
    Razavizadeh, S. Mohammad
    Iran Univ Sci & Technol IUST, Elect Engn Dept, Tehran 1684613114, Iran..
    Farhadi, Hamed
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap. Ericsson Res, SE-16440 Stockholm, Sweden..
    Svensson, Tommy
    Chalmers Univ Technol, Dept Elect Engn, S-41296 Gothenburg, Sweden..
    Secure Simultaneous Information and Power Transfer for Downlink Multi-User Massive MIMO2020Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 150514-150526Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, downlink secure transmission in simultaneous information and power transfer (SWIPT) system enabled with massive multiple-input multiple-output (MIMO) is studied. A base station (BS) with a large number of antennas transmits energy and information signals to its intended users, but these signals are also received by an active eavesdropper. The users and eavesdropper employ a power splitting technique to simultaneously decode information and harvest energy. Massive MIMO helps the BS to focus energy to the users and prevent information leakage to the eavesdropper. The harvested energy by each user is employed for decoding information and transmitting uplink pilot signals for channel estimation. It is assumed that the active eavesdropper also harvests energy in the downlink and then contributes during the uplink training phase. Achievable secrecy rate is considered as the performance criterion and a closed-form lower bound for it is derived. To provide secure transmission, the achievable secrecy rate is then maximized through an optimization problem with constraints on the minimum harvested energy by the user and the maximum harvested energy by the eavesdropper. Numerical results show the effectiveness of using massive MIMO in providing physical layer security in SWIPT systems and also show that our closed-form expressions for the secrecy rate are accurate.

  • 43.
    Gong, Dawei
    et al.
    Zhejiang University, National Engineering Research Center for Optical Instruments, Hangzhou, China; Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China.
    Yan, Lingling
    Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China.
    Gu, Binbin
    Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China.
    Zhang, Ruili
    Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China.
    Mao, Xinli
    Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China.
    He, Sailing
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektromagnetism och fusionsfysik. Wenzhou Medical University, Taizhou Hospital of Zhejiang Province, Linhai, China; Zhejiang University, Centre for Optical and Electromagnetic Research, Hangzhou, JORCEP, China.
    A Computer-Assisted Diagnosis System for the Detection of Chronic Gastritis in Endoscopic Images Using A Novel Convolution and Relative Self-Attention Parallel Network2023Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 11, s. 116990-117003Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chronic gastritis mainly includes chronic non-atrophic gastritis (CNAG), autoimmune gastritis (AIG), and type B gastritis. Early detection of AIG and type B gastritis will help identify high-risk groups for gastric cancer and prevent the development of irreversible peripheral neuropathy. We aim to develop a computer-assisted diagnosis (CADx) system by presenting a novel Convolution and Relative Self-Attention Parallel Network (CRSAPNet). We collected 3576 endoscopic images of chronic gastritis from 205 patients. MBConv and Relative Self-Attention Parallel Block (CRSAPB) was proposed to concatenate local features (such as mucosal folds and mucosal vessels extracted by MBConv) and global features (such as atrophied area extracted by Relative Self-Attention) in parallel in the last two stages of CRSAPNet. The CADx system distinguished AIG from type B gastritis and CNAG. The CRSAPNet achieved the highest overall accuracy of 95.44% (94.65% precision, 93.51% recall, 94.08% F1-score for AIG) with the fewest parameters. We used Grad-CAM to visually analyze the heat maps. We only replaced the original blocks of the third stage of ResNet50 and ConvNeXt-T with CRSAPB, resulting in an overall accuracy improvement of 0.37%, and 4.19%, respectively. Furthermore, the CADx system classified the three types of chronic gastritis for the first time. The CRSAPNet achieved an overall accuracy of 91.62%, and the overall accuracies in the location of the gastric body and gastric fundus were 93.43% and 92.51%, respectively. A new state-of-the-art deep learning network is introduced to distinguish AIG from type B gastritis and CNAG, and a classification for three types of chronic gastritis is reported for the first time.

  • 44.
    Gu, Song
    et al.
    Chengdu Aeronaut Polytech, Dept Aeronaut Engn, Chengdu 610100, Sichuan, Peoples R China..
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Hao, Wei
    Chengdu Aeronaut Polytech, Dept Aeronaut Engn, Chengdu 610100, Sichuan, Peoples R China..
    Du, Yingjie
    Chengdu Aeronaut Polytech, Dept Aeronaut Engn, Chengdu 610100, Sichuan, Peoples R China..
    Wang, Jian
    Chengdu Aeronaut Polytech, Dept Aeronaut Engn, Chengdu 610100, Sichuan, Peoples R China..
    Zhang, Weirui
    Chengdu Aeronaut Polytech, Dept Aeronaut Engn, Chengdu 610100, Sichuan, Peoples R China..
    Online Video Object Segmentation via Boundary-Constrained Low-Rank Sparse Representation2019Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 53520-53533Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Graphcut-based algorithm is adopted in many video object segmentation systems because different terms can be probabilistically fused together in a framework. Constructing spatio-temporal coherences is an important stage in segmentation systems. However, many steps are involved when computing a key term with good discriminative power. If the cascade steps are adopted, the inaccurate output of the previous step will definitely affect the next step, leading to inaccurate segmentation. In this paper, a key term that is computed by a single framework referred to as boundary-constrained low-rank sparse representation (BCLRSR) is proposed to achieve the accurate segmentation. By treating the elements as linear combinations of dictionary templates, low-rank sparse optimization is adopted to achieve the spatio-temporal saliency. For adding the spatial information to the low-rank sparse model, a boundary constraint is adopted in the framework as a Laplacian regularization. A BCLRSR saliency is then obtained by the represented coefficients, which measure the similarity between the elements in the current frame and the ones in the dictionary. At last, the object is segmented by minimizing the energy function, which is formalized by the spatio-temporal coherences. The experiments on some public datasets show that our proposed algorithm outperforms the state-of-the-art methods.

  • 45.
    Gulgun, Ziya
    et al.
    Linköping Univ, Dept Elect Engn ISY, S-58183 Linköping, Sweden..
    Larsson, Erik G.
    Linköping Univ, Dept Elect Engn ISY, S-58183 Linköping, Sweden..
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Multiple Spoofer Detection for Mobile GNSS Receivers Using Statistical Tests2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 166382-166394Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We consider Global Navigation Satellite Systems (GNSS) spoofing attacks and devise a countermeasure appropriate for mobile GNSS receivers. Our approach is to design detectors that, operating after the signal acquisition, enable the victim receiver to determine with high probability whether it is under a spoofing attack or not. Namely, the binary hypothesis is that either the GNSS receiver tracks legitimate satellite signals, H-0, or spoofed signals, H-1. We assume that there exists an unknown number of multiple spoofers in the environment and the attack strategy (which legitimate signals are spoofed by which spoofers) is not known to the receiver. Based on these assumptions, we propose an algorithm that identifies the number of spoofers and clusters the spoofing data by using Bayesian information criterion (BIC) rule. Depending on the estimated and clustered data we propose a detector, called as generalized likelihood ratio (GLRT)-like detector. We compare the performance of the GLRT-like detector with a genie-aided detector in which the attack strategy and the number of spoofers is known by the receiver. In addition to this, we extend the GLRT-like detector for the case where the noise variance is also unknown and present the performance results.

  • 46.
    Guzman-Henao, Jhony Andres
    et al.
    Fac Ingn, Dept Mecatron & Electromecan, Inst Tecnol Metropolitano, Medellin 130015, Colombia..
    Bolanos, Ruben Ivan
    Fac Ingn, Dept Mecatron & Electromecan, Inst Tecnol Metropolitano, Medellin 130015, Colombia..
    Montoya, Oscar Danilo
    Univ Distrital Francisco Jose de Caldas, Fac Ingn, Bogota 110231, Colombia..
    Grisales-Norena, Luis Fernando
    Univ Talca, Dept Elect Engn, Curico 110231, Chile..
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    On Integrating and Operating Distributed Energy Resources in Distribution Networks: A Review of Current Solution Methods, Challenges, and Opportunities2024Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 55111-55133Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The growing demand for electric power and the need for an energy transition that contributes to the reduction of global greenhouse gas emissions have driven the development of various energy generation, storage, and offset technologies. These technologies are known as distributed energy resources. Their integration into distribution power systems not only contributes to improving operating aspects, but also allows supplying electricity to areas that do not have access to large-scale power systems. Therefore, the integration and management of these resources has become a topic of interest, and several studies seek to optimize their impact on technical, economic, and environmental aspects. However, this optimization poses specific challenges related to the type and number of variables related to the operation of a distribution power system. This review article aims to describe the main challenges posed by three-phase AC three-phase distribution power systems under scenarios involving the integration of distributed energy resources. In addition, it presents some approaches proposed by different authors to improve the technical, economic, and environmental aspects of power grids. It can be stated that the strategies presented in the literature fail to consider scenarios that simultaneously integrate different types of technologies and optimize them while following a multi-objective approach and considering three-phase systems in a context of variable generation and demand. Therefore, future work in this field should address these aspects in a holistic manner, taking into account the computation efforts and processing times required by intelligent algorithms.

  • 47.
    Gómez, Francisco José
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Aguilera, Miguel
    Instituto Costaricense de Electricidad (ICE), San José, Costa Rica.
    Vanfretti, Luigi
    Olsen, Svein Harald
    Statnett SF, Oslo, Norway.
    Multi-Domain Semantic Information and Physical Behavior Modeling of Power Systems and Gas Turbines Expanding the Common Information Model2018Inngår i: IEEE Access, E-ISSN 2169-3536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rapid increase of Intermittent Energy Resources (IER) there is a need to have dispatchable production available to ensure secure operation and increase opportunity for energy system flexibility. Gas turbine-based power plants offer flexible operation that is being improved with new technology advancements. Those plants provide in general, quick start together with significant ramping capability, which can be exploited to balance IERs. Consequently, to understand this potential source of flexibility, better models for gas turbines are required for power systems studies and analysis. In this work both the required semantic information and physical behavior models of such multi-domain systems are considered. First, UML class diagrams and RDF schemas based on the Common Information Model (CIM) standards are used to describe the semantic information of the electrical power grid. An extension that exploits the ISO 15926 standard is herein proposed to derive the multi-domain semantics required by integrated electrical power grid with detailed gas turbine dynamic models. Second, the Modelica language is employed to create the equation-based models which represent the behavior of a multi-domain physical system. A comparative simulation analysis between the power system domain model and the multi-domain model has been performed. Some differences between the turbine dynamics representation of the commonly used GGOV1 standard model and a more detailed gas turbine model are shown.

    Fulltekst (pdf)
    fulltext
  • 48. He, Mingjia
    et al.
    Ma, Xinwei
    Jin, Yuchuan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE).
    Station Importance Evaluation in Dynamic Bike-Sharing Rebalancing Optimization Using an Entropy-Based TOPSIS Approach2021Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 38119-38131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an eco-friendly travel mode, bike-sharing has prevailed around the world. However, the systems are imbalanced due to the asymmetric spatial and temporal distribution of user demand. Station prioritization strategies are needed to rebalance more shared bikes for more important stations. This paper proposes an evaluation method of station importance in dynamic bike-sharing rebalancing. Firstly, a short-term demand prediction model is applied to capture the temporal and spatial characteristics of bike-sharing trip data and predict bike-sharing demand at the station level. Based on the prediction results, the method of determining rebalancing quantity is proposed with consideration of bike-sharing usage throughout the rebalancing period. Then, three criteria are employed to evaluate the importance of bike-sharing stations, including rebalancing quantity, closeness to inventory threshold, and distance from the key station. An entropy-based Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS) approach is proposed to weigh different criteria and evaluate station importance. Furthermore, the experiments on bike-sharing data from Nanjing City demonstrate the effectiveness of the proposed methods. This research is helpful for operators and managers to dynamically rebalance shared bikes with high efficiency and improve the service quality of bike-sharing systems.

  • 49. He, Wang
    et al.
    Xu, Bo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Gustafsson, Mats
    Ying, Zhinong
    He, Sailing
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    RF Compliance Study of Temperature Elevation in Human Head Model Around 28 GHz for 5G User Equipment Application: Simulation Analysis2018Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The crowdedness of current cellular bands and the demand for higher transmission speed prompt the use of the millimeter-wave spectrum for the next-generation mobile communication. In the millimeter-wave frequencies, the dosimetric quantity for human exposure to electromagnetic fields changes from the specific absorption rate to incident power density. In this paper, we used 28-GHz beam-steering patch arrays, a dipole antenna, and plane waves to investigate the temperature elevation in a multi-layer model of human head and its correlation with power density metrics. The power density averaged over one square-centimeter in free space and the peak temperature elevation in tissue at 28 GHz have good correlation. The peak temperature elevation indicated by the power density averaged one square-centimeter also agrees well with the peak temperature elevation induced by the plane waves. The results show that the averaging area of a few square-centimeters may be a good candidate for the spatial-average power density. The findings provide valuable input to the ongoing revision and updating of relevant safety standards and guidelines.

  • 50.
    He, Wang
    et al.
    Zhejiang Univ, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China..
    Xu, Bo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH). KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion. Ericsson AB, Ericsson Res, S-16480 Stockholm, Sweden.;KTH Royal Inst Technol, Dept Electromagnet Engn, S-10044 Stockholm, Sweden..
    Yao, Yuanqing
    Zhejiang Univ, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China..
    Colombi, Davide
    Ericsson AB, Ericsson Res, S-16480 Stockholm, Sweden..
    Ying, Zhinong
    Sony Corp, Sony Res Ctr, S-22188 Lund, Sweden..
    He, Sailing
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion. KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). Zhejiang Univ, Ctr Opt & Electromagnet Res, Hangzhou 310058, Peoples R China.;KTH Royal Inst Technol, Dept Electromagnet Engn, S-10044 Stockholm, Sweden..
    Implications of Incident Power Density Limits on Power and EIRP Levels of 5G Millimeter-Wave User Equipment2020Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 148214-148225Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    User equipment (UE) is required to comply with the relevant radio frequency (RF) electromagnetic field (EMF) exposure limits, which are of relevance to establish the maximum permissible transmitted power and the maximum equivalent isotropically radiated power (EIRP). Recently, international RF EMF exposure guidelines, such as those published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) as well as by the IEEE, have been updated. In this paper, the implications of the revised incident power density limits are investigated in terms of maximum permissible transmitted power and the maximum EIRP for devices operating in close proximity of the user. A similar analysis is conducted according to the US Federal Communications Commission (FCC) regulation on RF exposure. EMF compliance of UE is studied by means of numerical modelling of patch antenna arrays of different array sizes taking into consideration of possible beam-steering operations, at frequencies ranging from 10 GHz to 100 GHz. The results are compared with the 3rd Generation Partnership Project (3GPP) requirements on the total radiated power (TRP) and EIRP levels. The present implications of the incident power density limits for 5G millimeter-wave UE will give valuable insights to mobile equipment manufacturers, network operators, and standardization bodies.

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