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  • 1.
    Khan, Sajid
    et al.
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore.
    Shah, Ambika Prasad
    Institute for Microelectronics, Technische Universität Wien.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gupta, Neha
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore.
    Pandey, Jai Gopal
    Integrated System Group, CSIR-CEERI.
    Vishvakarma, Santosh Kumar
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore.
    A symmetric D flip-flop based PUF with improved uniqueness2020Ingår i: Microelectronics and reliability, ISSN 0026-2714, E-ISSN 1872-941X, Vol. 106, artikel-id 113595Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Physically unclonable functions (PUF) emerged as security primitives that generate high entropy, temper resilient bits for security applications. However, the implementation area budget limits their use in lightweight applications such as IoT, RFID, and biomedical applications. In the form of SRAM or D flip-flop, intrinsic PUFs are abundantly available in almost all of the designs. Being an integral part of the design, they can be used with compromised performance. In this work, to address the usage of intrinsic PUF, a D flip-flop based lightweight PUF is proposed. The proposed architecture is implemented on 40 nm CMOS technology. The simulation results show that it offers a uniqueness of 0.502 and the worst-case reliability of 95.89% at high temperature 125 °C and 97.89% at a supply voltage of 1.2 V. To evaluate the performance of various PUF architectures, A novel term, the uniqueness-to-reliability ratio, is proposed. When compared to the conventional D flip-flop, it offers 4.491 times more uniqueness and 127.74 times more uniqueness-to-reliability ratio with the same layout area. Since it uses the symmetrical structure, unlike other architectures, the proposed architecture does not require any post-processing schemes for bias removal, which further saves the silicon area. To verify the functional correctness of the simulation results, an FPGA implementation of the conventional and proposed D Flip-flop is also presented.

  • 2.
    Belay, Birhanu
    et al.
    Department of Computer Science, University of Kaiserslautern, Germany. Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Habtegebrial, Tewodros
    Department of Computer Science, University of Kaiserslautern, Germany.
    Meshesha, Million
    School of Information Science, Addis Ababa University, Ethiopia.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Belay, Gebeyehu
    Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Stricker, Didier
    Department of Computer Science, University of Kaiserslautern, Germany. German Research Center for Artificial Intelligence, DFKI, Germany.
    Amharic OCR: An End-to-End Learning2020Ingår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 3, artikel-id 1117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we introduce an end-to-end Amharic text-line image recognition approach based on recurrent neural networks. Amharic is an indigenous Ethiopic script which follows a unique syllabic writing system adopted from an ancient Geez script. This script uses 34 consonant characters with the seven vowel variants of each (called basic characters) and other labialized characters derived by adding diacritical marks and/or removing parts of the basic characters. These associated diacritics on basic characters are relatively smaller in size, visually similar, and challenging to distinguish from the derived characters. Motivated by the recent success of end-to-end learning in pattern recognition, we propose a model which integrates a feature extractor, sequence learner, and transcriber in a unified module and then trained in an end-to-end fashion. The experimental results, on a printed and synthetic benchmark Amharic Optical Character Recognition (OCR) database called ADOCR, demonstrated that the proposed model outperforms state-of-the-art methods by 6.98% and 1.05%, respectively.

  • 3.
    Palm, Emanuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Approaching Non-Disruptive Distributed Ledger Technologies via the Exchange Network Architecture2020Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 8, s. 12379-12393Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rise of distributed ledger technologies, such as R3 Corda, Hyperledger Fabric and Ethereum, has lead to a surge of interest in digitalizing different forms of contractual cooperation. By allowing for ledgers of collaboration-critical data to be reliably maintained between stakeholders without intermediaries, these solutions might enable unprecedented degrees of automation across organizational boundaries, which could have major implications for supply chain integration, medical journal sharing and many other use cases. However, these technologies tend to break with prevailing business practices by relying on code-as-contracts and distributed consensus algorithms , which can impose disruptive requirements on contract language, cooperation governance and interaction privacy. In this paper, we show how our Exchange Network architecture could be applied to avoid these disruptors. To be able to reason about the adequacy of our architecture, we present six requirements for effective contractual collaboration, which notably includes negotiable terms and effective adjudication . After outlining the architecture and our implementation of it, we describe how the latter meets our requirements by facilitating (1) negotiation, (2) user registries, (3) ownership ledgers and (4) definition sharing, as well as by only replicating ledgers between stakeholder pairs. To show how our approach compares to other solutions, we also consider how Corda, Fabric and Ethereum meet our requirements. We conclude that digital negotiation and ownership could replace many proposed uses of code-as-contracts for better compatibility with current contractual practices, as well as noting that distributed consensus algorithms are not mandatory for digital cooperation.

  • 4.
    Pamidi, Taraka Rama Krishna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Shankar, Vijay
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Comparison of two different ultrasound reactors for the treatment of cellulose fibers2020Ingår i: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 62, artikel-id 104841Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The pulp and paper industry is in continuous need for energy-efficient production processes. In the refining process of mechanical pulp, fibrillation is one of the essential unit operations that count for up to 80% of the total energy use. This initial study explores the potential and development of new type of scalable ultrasound reactor for energy efficient mechanical pulping. The developed reactor is of continuous flow type and based on both hydrodynamic and acoustic cavitation in order to modify the mechanical properties of cellulose fibers. A comparison of the prototype tube reactor is made with a batch reactor type where the ultrasonic horn is inserted in the fluid. The pulp samples were sonicated by high-intensity ultrasound, using tuned sonotrodes enhancing the sound pressure and cavitation intensity by a controlled resonance in the contained fluid. The resonant frequency of the batch reactor is 20.8 kHz and for the tube reactor it is 22.8 kHz. The power conversion efficiency for the beaker setup is 25% and 36% in case of the tube reactor in stationary mode. The objective is to verify the benefit of resonance enhanced cavitation intensity when avoiding the effect of Bjerkenes forces. The setup used enables to keep the fibers in the pressure antinodes of the contained fluid. In case of the continuous flow reactor the effect of hydrodynamic cavitation is also induced. The intensity of the ultrasound in both reactors was found to be high enough to produce cavitation in the fluid suspension to enhance the fiber wall treatment. Results show that the mechanical properties of the fibers were changed by the sonification in all tests. The continuous flow type was approximately 50% more efficient than the beaker. The effect of keeping fibers in the antinode of the resonant mode shape of the irradiation frequency was also significant. The effect on fiber properties for the tested mass fraction was determined by a low-intensity ultrasound pulse-echo based measurement method, and by a standard pulp analyzer.

  • 5.
    Borngrund, Carl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Dump truck object detection dataset including scale-models2020Dataset
    Abstract [sv]

    Detektering av föremål är en viktig del i de flesta självkörande fordonssystemen och för att nå en hög prestanda behövs data. För att kunna detektera föremål i bilder brukar man använda sig av neurala nätverk. Nätet brukar ta bildinformation som input och resultatet är samma bild där nätet har detekterat, lokaliserat och klassificerat alla föremålen i bilden.När man tränar ett nät för att utföra denna uppgift brukar stora dataset användas, tyvärr är det inte alltid praktiskt att samla stora mängder data. Detta har lett till att man använder olika tekniker vilket låter oss uppnå bra prestanda med mindre mängd data. Exempel på dessa tekniker är Transfer learning och Domain adaptation. Då det är en väldigt tidskrävande process att arbeta med arbetsfordon ville vi se ifall det var möjligt att använda skalenliga modeller i olika miljöer för att träna ett nätverk och sedan se ifall nätverket kunde detektera liknande föremål på fullskaliga arbetsfordon utan någon extra träning.Detta mindre datasetet innehåller bilder på en skalenliga dumper i olika miljöer som tränings- och valideringsdata. Testdatat innehåller bilder på en fullskalig dumper av liknande modell. Målet med datasetet är att använda transfer learning eller domain adaptation för att detektera och klassificera tre olika klasser av föremål, hjul, förarhytt och flak.

  • 6.
    Paniagua, Cristina
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Efficient Device-to-Device Service Invocation Using Arrowhead Orchestration2020Ingår i: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 7, nr 1, s. 429-439Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Internet of Things (IoT) enables interaction from real-world physical objects using sensors to the virtual world of computers and the Internet. The use of service-oriented architecture (SOA) is one step in the creation of basic and complex interactions between several sensors and actuators. However, the use of SOA-enabled technologies alone does not meet all requirements of how sensor and actuator systems could be integrated to create distributed monitoring and control applications. The centralized, traditional method of communication in wireless sensor networks via a gateway presents drawbacks that have to be addressed; device-to-cloud communication adds higher latency and higher power consumption and is less robust than the device-to-device (D2D) communication approach. Moreover, all these characteristics reduce the scalability of the network, thus limiting the use of IoT in the industry. In this article, the proposed method utilizes the arrowhead framework orchestration system to generate service composition within a (wireless) network formed by IoT devices. The aim is to achieve efficient D2D service invocation to reduce the drawbacks of today's widely used device-to-cloud approach. The method in this article performs efficient service composition for industrial IoT, including mapping SOA service composition in very small resource-constrained devices using the arrowhead orchestration. The results presented in this article at the service level can increase performance and robustness in fog computing on resource-constrained devices.

  • 7.
    Adewumi, Oluwatosin
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Inner For-Loop for Speeding Up Blockchain Mining2020Ingår i: Open Computer Science, ISSN 2299-1093, Vol. 10, nr 1, s. 42-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the authors propose to increase the efficiency of blockchain mining by using a population-based approach. Blockchain relies on solving difficult mathematical problems as proof-of-work within a network before blocks are added to the chain. Brute force approach, advocated by some as the fastest algorithm for solving partial hash collisions and implemented in Bitcoin blockchain, implies exhaustive, sequential search. It involves incrementing the nonce (number) of the header by one, then taking a double SHA-256 hash at each instance and comparing it with a target value to ascertain if lower than that target. It excessively consumes both time and power. In this paper, the authors, therefore, suggest using an inner for-loop for the population-based approach. Comparison shows that it’s a slightly faster approach than brute force, with an average speed advantage of about 1.67% or 3,420 iterations per second and 73% of the time performing better. Also, we observed that the more the total particles deployed, the better the performance until a pivotal point. Furthermore, a recommendation on taming the excessive use of power by networks, like Bitcoin’s, by using penalty by consensus is suggested.

  • 8.
    Chouhan, Shailesh Singh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Halonen, Kari
    Department of Electronics and Nanoengineering, Aalto University, Espoo, Finland.
    A 40 nW CMOS-Based Temperature Sensor with Calibration Free Inaccuracy within ±0.6 ◦C2019Ingår i: Electronics, ISSN 2079-9292, Vol. 8, nr 11, artikel-id 1275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, a temperature equivalent voltage signal was obtained by subtracting output voltages received from two individual temperature sensors. These sensors work in the subthreshold region and generate the output voltage signals that are proportional and complementary to the temperature. Over the temperature range of −40 ∘" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">∘C to +85 ∘" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">∘C without using any calibration method, absolute temperature inaccuracy less than ±0.6 ∘" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">∘C was attained from the measurement of five prototypes of the proposed temperature sensor. The implementation was done in a standard 0.18 μ" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">μ m CMOS technology with a total area of 0.0018 mm 2" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">2. The total power consumption is 40 nW for a supply voltage of 1.2 V measured at room temperature.

  • 9.
    Gustafsson, Lennart
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A Case of Near-Optimal Sensory Integration Based on Kohonen Self-Organizing Maps2019Ingår i: Neural Computation, ISSN 0899-7667, E-ISSN 1530-888X, Vol. 31, nr 7, s. 1419-1429Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This letter shows by digital simulation that a simple rule applied to one-dimensional self-organized maps for integrating sensory perceptions from two identical sources yielding position information as integers, corrupted by independent noise sources, yields almost statistically optimal results for position estimation as determined by maximum likelihood estimation. There is no learning of the corrupting noise sources nor is any information about the statistics of the noise sources available to the integrating process. The simple rule employed yields a measure of the quality of the estimated position of the source. The letter also shows that if the Bayesian estimates, which are rational numbers, are rounded in order to comply with the stipulation that integers be identified, the Bayesian estimation will have a larger variance than the proposed integration.

  • 10.
    Röijezon, Ulrik
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Prellwitz, Maria
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Ahlmark, Daniel Innala
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A haptic navigation aid for individuals with visual impairments: Indoor and outdoor feasibility evaluations of the LaserNavigator2019Ingår i: Journal of Visual Impairment & Blindness, ISSN 0145-482X, E-ISSN 1559-1476, Vol. 113, nr 2, s. 194-201Artikel i tidskrift (Refereegranskat)
  • 11.
    Sharma, Vishal
    et al.
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore .
    Gopal, Maisagalla
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore .
    Singh, Pooran
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore .
    Vishvakarma1, Santosh Kumar
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore .
    Chouhan, Shailesh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A robust, ultra low-power, data-dependent-power-supplied 11T SRAM cell with expanded read/write stabilities for internet-of-things applications2019Ingår i: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 98, nr 2, s. 331-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the increased requirement of on-chip data computations in internet of things based applications, the embedded on-chip SRAM memory has been under its renovation stage to overcome the classical problems like stability and poor energy efficiency. In this work, a data-dependent-power-supply mechanism for a new 11T SRAM cell is proposed with ultra-low leakage and improved read/write stability against the process–voltage–temperature variations. The proposed cell consumes static power in the fraction of picowatt range and has considerable enhancement in the value of write static noise margin (WSNM). In addition, the use of associated read decoupling approach, with the column-based read buffer, further improves the read stability of the proposed cell and make it comparable with the hold stability value. The percentage reduction in the leakage power of proposed 11T cell is 99.97%">99.97% 99.97% , 99.93%">99.93% 99.93% and 99.97%">99.97% 99.97% , while the WSNM 1 is 6.98×">6.98× 6.98× , 3.12×">3.12× 3.12× and 1.46×">1.46× 1.46× , and WSNM 0 is 5.55×">5.55× 5.55× , 1.25×">1.25× 1.25× and 1.16×">1.16× 1.16× larger when operating at 0.4 V and compared to the conventional 6T and threshold voltage techniques based VTH_9T and data aware write assist (DAWA) 12T SRAM cell structures respectively. Iread/Ileak">I read /I leak  Iread/Ileak ratio for the proposed cell has improved by 6.55×">6.55× 6.55× , 6.22×">6.22× 6.22× and 5.11×">5.11× 5.11× when compared with the 6T, VTH_9T and DAWA12T SRAM to increase the memory density. Further, the post-layout Monte Carlo simulation results (2000 samples) confirm the robustness of the proposed cell against the process variations.

  • 12.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Shankar, Vijay
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Acoustic design principles for energy efficient excitation of a high intensity cavitation zone2019Ingår i: Proceedings of the 23rd International Congress on Acoustics, integrating 4th EAA Euroregio 2019: ICA 2019, 9 - 13 September / [ed] Martin Ochmann, Aachen, Germany, 2019, s. 948-955Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Energy-efficient process intensification is a key aspect for a sustainable industrial production. To improve energy conversion efficiency high intensity cavitation is a promising method, especially in cases where the material to be treated is valuable and on the micro meter scale. Transient collapsing cavitation bubbles gives powerful effects on objects immersed in fluids, like cellulose fibers, mineral particles, enzymes, etc. The cavitation process needs optimization and control, since optimal conditions is multivariate challenge. This study focuses on different design principles to achieve high intensity cavitation in a specific volume in a continuous flow. This study explores some potential design principles to obtain energy efficient process intensification. The objective is to tune several different resonance phenomena to create a powerful excitation of a flowing suspension (two-phase flow and cavitation bubbles). The reactor is excited by sonotrodes, connected to two coupled resonant tube structures, at the critical frequency. Finally cavitation bubbles are initiated by a flow through a venturi nozzle. The acoustically optimised reactor geometry is modelled in Comsol Multiphysics®, and excited by dedicated ultrasound signals at three different frequencies. The effect of the high intensity cavitation is experimentally evaluated by calorimetric method, foil tests and degree of fibrillation on cellulose fibers.

  • 13.
    Khan, Sajid
    et al.
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, India.
    Shah, Ambika Prasad
    Institute for Microelectronics, Technische Universität Wien, Vienna, Austria.
    Gupta, Neha
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, India.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pandey, Jai Gopal
    Integrated System Group, CSIR-CEERI, Pilani, Rajasthan, India.
    Vishvakarma, Santosh Kumar
    Nanoscale Devices, VLSI Circuit & System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, India.
    An ultra-low power, reconfigurable, aging resilient RO PUF for IoT applications2019Ingår i: Microelectronics Journal, ISSN 0959-8324, Vol. 92, artikel-id 104605Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Physically Unclonable Functions (PUF) have emerged as security primitives which can generate high entropy, temper resilient bits for security applications. However, the power budget of the ring oscillator (RO) PUF limits the use of RO PUF in IoT applications, in this concern a low power variant of RO PUF is much needed. In this paper, we have presented an ultra-low power, lightweight, configurable RO PUF based on the 4T XOR architecture. The proposed architecture is aging resilient; hence it produces a stable PUF output over the years. Also, it has a large number of challenge-response-pair (CRP) compared to the other architectures, which makes it suitable for chip identification as well as cryptographic key generation. The proposed PUF is implemented on 40 nm CMOS technology, and for the validation of design, we have also implemented on FPGA. The simulation results show that it has a uniqueness of 0.489 and worst-case reliability of 96.43% and 93.15% at 125 °C and 1.2 V, respectively. Compared to the conventional RO PUF it consumes 98.06% and 95.47% less dynamic and leakage power, respectively.

  • 14.
    Bhoi, Bandan Kumar
    et al.
    Department of Electronics and Telecommunication, Veer Surendra Sai, University of Technology, Burla, India.
    Misa, Neeraj Kumar
    Department of Electronics and Communication Engineering, Bharat Institute of Engineering and Technology, Hyderabad, India.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Acharya, Sarthak
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Analyzing Design Parameters of Nano-Magnetic Technology Based Converter Circuit2019Ingår i: VLSI Design and Test: 23rd International Symposium, VDAT 2019, Indore, India, July 4–6, 2019, Revised Selected Papers / [ed] Dr. Anirban Sengupta, Dr. Sudeb Dasgupta, Virendra Singh, Rohit Sharma, Santosh Kumar Vishvakarma, Springer, 2019, s. 34-46Konferensbidrag (Refereegranskat)
    Abstract [en]

    Digital circuits need improvement in computation speed, reducing circuit complexity and power consumption. Emerging Technology NML can be such an architecture at nano-scale and thus emerges as a viable alternative for the digital CMOS VLSI. This technology has the capability to compute the logic as well as storage into the same device, which points out that it great potential for emerging technology. Since Nano-magnetic, technology fast approaches its minimal feature size, high device density and operate at room temperature. NML based circuits synthesis has to opt for novel half subtraction and Binary-to-Gray architecture for achieving minimal complexity and high-speed performance. This manuscript pro-poses area efficient binary half-subtraction and Binary-to-Gray converter architecture. Circuits’ synthesize are performed by MagCAD tool and simulate by Modelsim simulator. The circuit’s performance are estimated over other existing designs. The proposed converter consume 73.73%, and 94.49% less area than the converter designed using QCA and CMOS technique respectively. This is a significant contribution to this paper. Simulation results of converter show that the critical path delay falls within 0.15 µs.

  • 15.
    Kovács, G
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. MTA SZTE Research Group on Artificial Intelligence, Szeged, Hungary.
    Szekrényes, István
    Institute of Philosophy, University of Debrecen, Debrecen, Hungary.
    Applying Neural Network Techniques for Topic Change Detection in the HuComTech Corpus2019Ingår i: The Temporal Structure of Multimodal Communication / [ed] László Hunyadi, István Szekrényes, Switzerland: Springer Nature , 2019, s. 147-162Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In the age of The Internet we are generating documents (both written and spoken) at an unprecedented rate. This rate of document creation—as well as the number of already existing documents—makes manual processing time-consuming and costly to the point of infeasibility. This is the reason why we are in need of automatic methods that are suitable for the processing of written as well as spoken documents. One crucial part of processing documents is partitioning said documents into different segments based on the topic being discussed. A self-evident application of this would be for example partitioning a news broadcast into different news stories. One of the first steps of doing so would be identifying the shifts in the topic framework, or in other words, finding the time-interval where the announcer is changing from one news story to the next. Naturally, as the transition between news stories are often accompanied by easily identifiable audio—(e.g. signal) and visual (e.g. change in graphics) cues, this would not be a particularly different task. However, in other cases the solution to this problem would be far less obvious. Here, we approach this task for the case of spoken dialogues (interviews). One particular difficulty of these dialogues is that the interlocutors often switch between languages. Because of this (and in the hope of contributing to the generality of our method) we carried out topic change detection in a content-free manner, focusing on speaker roles, and prosodic features. For the processing of said features we will employ neural networks, and will demonstrate that using the proper classifier combination methods this can lead to a detection performance that is competitive with that of the state-of-the-art.

  • 16.
    Paniagua, Cristina
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Architectural approach for Autonomous System of Systems Interoperability2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The current technological environment is evolving increasingly fast, and the development of new devices, technologies, and architectures has opened an emergent era where the digital and physical world work together. The implementation and use of systems based on a service-oriented architecture (SOA) in conjunction with the Internet of Things (IoT) and cyberphysical systems (CPS) have been extended during the last decades in numerous scenarios in industry and other domains. However, some of the major barriers to this approach are the lack of interoperability and the amount of engineering effort required for their integration.

     

    The research presented in this thesis targets issues related to digitalization and automation. It is framed by the Industry 4.0 paradigm, which promotes the rise of efficiency and sustainability on industrial production. The interoperability between heterogeneous systems and different domains is one of the main challenges of Industry 4.0. The quest for solutions that help to increase interoperability is an important part of this research.

     

    This thesis proposes a set of architectural design principles and tools in order to reduce engineering effort by means of finding solutions that enable autonomous integration and increase interoperability without human intervention. The research is focused on the IoT field, taking into account resource-constrained devices, system of systems integration, and data models.

     

    A detailed investigation of various interoperability mismatch problems is presented in this thesis. The proposed solution is an adapter system that can aid in the generation of new service consumer interfaces at both compile-time and run-time. The proposed approach requires a new point of view in the service description field that can provide a holistic description of the information required for the generation of consumer interfaces.

    In addition, aspects related to interoperability, such as the multiple IoT frameworks in the current market, naming conventions, syntactic modeling and translation, and security, are also partially analyzed.

     

    On a separate track, service composition in resource-constrained devices

     is analyzed in terms of latency, using the orchestration provided by the Arrowhead Framework.

  • 17.
    Alberti, Michele
    et al.
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Pondenkandath, Vinaychandran
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Würsch, Marcel
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Bouillon, Manuel
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Seuret, Mathias
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Ingold, Rolf
    Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Document Image and Voice Analysis Group (DIVA), University of Fribourg, Fribourg, Switzerland.
    Are You Tampering with My Data?2019Ingår i: Computer Vision – ECCV 2018 Workshops: Proceedings, Part II / [ed] Laura Leal-Taixé & Stefan Roth, Springer, 2019, s. 296-312Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose a novel approach towards adversarial attacks on neural networks (NN), focusing on tampering the data used for training instead of generating attacks on trained models. Our network-agnostic method creates a backdoor during training which can be exploited at test time to force a neural network to exhibit abnormal behaviour. We demonstrate on two widely used datasets (CIFAR-10 and SVHN) that a universal modification of just one pixel per image for all the images of a class in the training set is enough to corrupt the training procedure of several state-of-the-art deep neural networks, causing the networks to misclassify any images to which the modification is applied. Our aim is to bring to the attention of the machine learning community, the possibility that even learning-based methods that are personally trained on public datasets can be subject to attacks by a skillful adversary.

  • 18.
    Kovács, György
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. MTA-SZTE Research Group on Artificial Intelligence, Szeged, Hungary.
    Balogh, Vanda
    Institute of Informatics, University of Szeged, Szeged, Hungary.
    Mehta, Purvnashi
    MindGarage, Kaiserslautern, Germany.
    Shridhar, Kumar
    MindGarage, Kaiserslautern, Germany.
    Alonso, Pedro
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Author Profiling Using Semantic and Syntactic Features: Notebook for PAN at CLEF 20192019Ingår i: CLEF 2019 Working Notes: Working Notes of CLEF 2019 - Conference and Labs of the Evaluation Forum / [ed] Linda Cappellato, Nicola Ferro, David E. Losada, Henning Müller, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present an approach for the PAN 2019 Author Profiling challenge. The task here is to detect Twitter bots and also to classify the gender of human Twitter users as male or female, based on a hundred select tweets from their profile. Focusing on feature engineering, we explore the semantic categories present in tweets. We combine these semantic features with part of speech tags and other stylistic features – e.g. character floodings and the use of capital letters – for our eventual feature set. We have experimented with different machine learning techniques, including ensemble techniques, and found AdaBoost to be the most successful (attaining an F1-score of 0.99 on the development set). Using this technique, we achieved an accuracy score of 89.17% for English language tweets in the bot detection subtask

  • 19.
    Garcia Represa, Jaime
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Autonomous Production Workstation Operation, Reconfiguration and Synchronization2019Ingår i: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 39, s. 226-234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The decoupling of production line’s workstations and its equipment from the higher layers in an automation architecture has thepotential to provide the following benefits: 1. Dynamic workstation reconfiguration; 2. Autonomous synchronization of workstationequipment; 3. Autonomous workstation operation.Each of these benefits will improve the automation flexibility at each workstation and for the whole production line.Introducing IoT equipment into workstations and making use of Service Oriented Architecture (SOA) fundamentals such as lookup,late binding and loose coupling are shown here to provide the above benefits. In addition, the cost of such an implementationand deployment seems to be significantly less than the comparable cost for legacy technology.An implementation, using the SOA approach on a workstation, at the Volvo Trucks production facility in Gothenburg was madepossible thanks to the Arrowhead framework, which has been shown to provide all three listed improvements.The analysis of the above-mentioned demonstration clearly shows how the workstation reconfiguration is made simple usingthe arrowhead ServiceRegistry system. Autonomous synchronization is achieved through the look-up and late binding capabilitiesprovided by the arrowhead Orchestration system in cooperation with the ServiceRegistry system. Finally, autonomous workstationoperation is provided through the support of the arrowhead Workflow Manager and Workflow Executor systems.All these benefits were achieved at a significantly reduced cost compared to comparable legacy implementation.

  • 20.
    Hartman, Andreas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bandlimited Distortionless Material Design by an Approximation of the Heaviside Condition2019Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The distortionless propagation of signals in a medium offers a way to preserve the signal integrity. There exists a condition for distortionless propagation on a transmission line known as the Heaviside condition. This paper proposes the use of the Heaviside condition to characterize and design magneto-dielectric materials that provide distortionless propagation in a specified finite frequency band. Plane wave propagation in a magneto-dielectric material is modeled by a transmission line model, thereby assuming transverse electromagnetic mode propagation. Then, the Heaviside condition is employed to derive the frequency-dependent permittivity and permeability functions of the material in rational form, so they satisfy the condition in a specified frequency interval. A procedure to design such materials is described. A numerical example of the design process is provided and an illustration of the effectiveness of modeled material in fulfilling the Heaviside condition in a specified frequency interval both in the time and frequency domains is given, indicating the validity of the approximation. The design procedure is as such a suitable preliminary design guide for deriving a realizable description of a magnetodielectric, exhibiting the distortionless property in the desired frequency interval, with certain specified requirements put on the loss, or the permeability and permittivity values satisfied. The obtained results may initiate further investigations into the bandwidth restrictions of the approximation, on closed-form design solutions, and the practical realization of such materials.

  • 21.
    Maergner, Paul
    et al.
    Department of Informatics, DIVA Group, University of Fribourg, Fribourg, Switzerland.
    Pondenkandath, Vinaychandran
    Department of Informatics, DIVA Group, University of Fribourg, Fribourg, Switzerland.
    Alberti, Michele
    Department of Informatics, DIVA Group, University of Fribourg, Fribourg, Switzerland.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Riesen, Kaspar
    Institute for Information Systems, University of Applied Sciences and Arts Northwestern Switzerland, Olten, Switzerland.
    Ingold, Rolf
    Department of Informatics, DIVA Group, University of Fribourg, Fribourg, Switzerland.
    Fischer, Andreas
    Department of Informatics, DIVA Group, University of Fribourg, Fribourg, Switzerland.Institute of Complex Systems, University of Applied Sciences and Arts Western Switzerland, Fribourg, Switzerland.
    Combining graph edit distance and triplet networks for offline signature verification2019Ingår i: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 125, s. 527-533Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Offline signature verification is a challenging pattern recognition task where a writer model is inferred using only a small number of genuine signatures. A combination of complementary writer models can make it more difficult for an attacker to deceive the verification system. In this work, we propose to combine a recent structural approach based on graph edit distance with a statistical approach based on deep triplet networks. The combination of the structural and statistical models achieve significant improvements in performance on four publicly available benchmark datasets, highlighting their complementary perspectives.

  • 22.
    Pamidi, Taraka Rama Krishna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Comparison of Cavitation Effect in Case of Fixed and Free Fibers in an Ultrasound Beaker2019Ingår i: Proceedings of the 23rd International Congress on Acoustics, integrating 4th EAA Euroregio 2019: ICA 2019, 9 - 13 September / [ed] Martin Ochmann, Aachen, Germany, 2019, s. 8217-8224Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In this study, we investigate the impact of high-intensity ultrasound treatment on the mechanical properties of pulp fibers. The pulp fiber samples are sonicated in an acoustically optimised beaker where high-intensity ultrasound is generated using a tuned sonotrode device. The idea is to create a controlled resonance to efficiently enhance the sound pressure in the beaker. Input power is 90Watt. The objective is to define the difference between freely suspended fibers in a beaker compared to keeping fibers in a fixed position. The hypothesis is that fiber treatment at a specific input power will be more efficient in the case when fibers are kept in a high pressure zone. Since the fiber wall is a layered structure, it is likely to delaminate internally which will affect the mechanical properties of the fiber. The effect on fiber properties is verified by measuring the ultrasound attenuation spectra for the treated fibers. The attenuation measurements are based on measurements of a low-intensity ultrasound pulse-echo technique. On a macroscopic scale, changes in the attenuation spectra relates to a change in mechanical properties of the fiber wall, since the suspended fibers more or less retain their diameter and length distributions.

  • 23.
    Al-Maqdasi, Zainab
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hajlane, Abdelghani
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Materials Science and Nano-engineering, Mohammed VI Polytechnic University, Benguerir, Morocco.
    Renbi, Abdelghani
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ouarga, Ayoub
    Materials Science and Nano-engineering, Mohammed VI Polytechnic University, Benguerir, Morocco.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Joffe, Roberts
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Conductive Regenerated Cellulose Fibers by Electroless Plating2019Ingår i: Fibers, ISSN 2079-6439, Vol. 7, nr 5, artikel-id 38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Continuous metallized regenerated cellulose fibers for advanced applications (e.g. multi-functional composites) are produced by electroless copper plating. Copper is successfully deposited on the surface of cellulose fibers using commercial cyanide-free electroless copper plating package commonly available for manufacturing of printed wiring boards. The deposited copper is found to enhance the thermal stability, electrical conductivity and resistance to moisture uptake of the fibers. On the other hand, involved chemistry results in altering the molecular structure of the fibers as is indicated by the degradation of their mechanical performance (tensile strength and modulus).

  • 24.
    Adewumi, Oluwatosin
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Foteini
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Conversational Systems in Machine Learning from the Point of View of the Philosophy of Science—Using Alime Chat and Related Studies2019Ingår i: Philosophies, ISSN 2409-9287, Vol. 4, nr 3, artikel-id 41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This essay discusses current research efforts in conversational systems from the philosophy of science point of view and evaluates some conversational systems research activities from the standpoint of naturalism philosophical theory. Conversational systems or chatbots have advanced over the decades and now have become mainstream applications. They are software that users can communicate with, using natural language. Particular attention is given to the Alime Chat conversational system, already in industrial use, and the related research. The competitive nature of systems in production is a result of different researchers and developers trying to produce new conversational systems that can outperform previous or state-of-the-art systems. Different factors affect the quality of the conversational systems produced, and how one system is assessed as being better than another is a function of objectivity and of the relevant experimental results. This essay examines the research practices from, among others, Longino’s view on objectivity and Popper’s stand on falsification. Furthermore, the need for qualitative and large datasets is emphasized. This is in addition to the importance of the peer-review process in scientific publishing, as a means of developing, validating, or rejecting theories, claims, or methodologies in the research community. In conclusion, open data and open scientific discussion fora should become more prominent over the mere publication-focused trend.

  • 25.
    Nilsson, Joakim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Imperial Coll, Dept Phys, London SW7 2AZ, England.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Correction: Maximal Q Factor for an On-Chip, Fuse-Based Trimmable Capacitor2019Ingår i: Electronics, ISSN 2079-9292, Vol. 8, nr 6, artikel-id 688Artikel i tidskrift (Refereegranskat)
  • 26.
    Martin del Campo Barraza, Sergio
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Schnabel, Stephan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Marklund, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Detection of particle contaminants in rolling element bearings with unsupervised acoustic emission feature learning2019Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 132, s. 30-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The detection of contaminants in the lubricant of rolling element bearings using acoustic emission signals is a challenging problem, in particular at high rotational speeds. This problem calls for new analysis methods beyond the conventional amplitude- and frequency-based methods. Feature learning is successfully used in the machine learning field to characterize complex signals. Here we use an unsupervised feature learning approach to distinguish acoustic emission signals. We investigate the repetition rates of features identified with shift-invariant dictionary learning and find that the signature of contaminated lubricant is significantly stronger than the effect on conventional condition indicators like the RMS and the enveloped RMS at rotational speeds above 300 rpm and up to 3000 rpm.

  • 27.
    Khan, Sajid
    et al.
    Nanoscale Devices, VLSI Circuit and System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore, India.
    Gupta, Neha
    Nanoscale Devices, VLSI Circuit and System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore, India.
    Vishvakarma, Abhinav
    Nanoscale Devices, VLSI Circuit and System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore, India.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pandey, Jai Gopal
    Integrated Systems Group, CSIR- Central Electronics Engineering Research Institute (CEERI)Pilani, India.
    Vishvakarma, Santosh Kumar
    Nanoscale Devices, VLSI Circuit and System Design Lab, Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore, India.
    Dual-Edge Triggered Lightweight Implementation of AES for IoT Security2019Ingår i: VLSI Design and Test: 23rd International Symposium, VDAT 2019, Indore, India, July 4–6, 2019, Revised Selected Papers / [ed] Sengupta A., Dasgupta S., Singh V., Sharma R., Kumar Vishvakarma S., Springer, 2019, s. 298-307Konferensbidrag (Refereegranskat)
    Abstract [en]

    Internet of Things (IoT) is now a growing part of our life. More than 10 billion devices are already connected, and more are expected to be deployed in the next coming years. To provide a practical solution for security, privacy and trust is the main concern for deploying IoT in such a large scale. For security and privacy in IoT, cryptography is the required solutions. AES algorithm is a well known, highly secure and symmetric key algorithm, but the area and power budget of AES makes it unsuitable for IoT Security. In this paper, we have presented a lightweight implementation of AES, with dual-edge triggered S-box. The proposed architecture has been implemented on FPGA as well as in ASIC on 180 nm technology. The proposed architecture uses a 32-bit data path to encrypt 128-bit plain-text with 128-bit cipher-key. ASIC implementation of the proposed architecture results in low-power (122.7 μ" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">μμW at 1 V) consumption with a reduction in the hardware overhead by 30% and a throughput of 23 Mbps at 10 MHz clock frequency.

  • 28.
    Hartman, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Electromagnetic Modeling with Complex Dielectrics: A Partial Element Equivalent Circuit Approach2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Wireless communication systems have become an integral part of many complex systems in diverse areas of society, for the exchange of data in business and industrial settings. With the advent of Internet of Things (IoT) and wireless sensor network architectures, the tighter demands on interoperability between different devices are putting heavy requirements their ability to exchange data wirelessly among them reliably. However, many environments pose a challenging setting for a wireless communication system to operate within. Consequently, electromagnetic modeling could be used as a crucial part of the analysis and design of a wireless communication system in these environments.

    In this thesis, means for the electromagnetic modeling of complex materials are considered. Specifically, the incorporation of dielectrics that exhibit loss, dispersion, and anisotropic properties into electromagnetic codes is addressed. The work has been executed within the partial element equivalent circuit (PEEC) method framework.

    First, a PEEC implementation that incorporates dispersive and lossy dielectrics, represented by equivalent circuit models explicitly included in the PEEC equations, is developed. This provides a descriptor system form of the PEEC model that includes dielectrics with permittivities that can be represented as finite sums of Debye and Lorentz permittivity models and can be integrated by any time integration scheme of choice. Additionally, the description admits the application of model-order reduction techniques, reducing the model complexity of a large-scale PEEC model that consists of frequency-dispersive dielectrics.

    Next, the incorporation of anisotropic dielectrics in PEEC simulations is considered. A PEEC cell for anisotropic dielectrics, with a general permittivity tensor, is derived. It turns out to be an extension of the standard dielectric PEEC cell for an isotropic dielectric by adding a voltage-dependent current source in parallel with the excess capacitance of the dielectric cell. A cross-coupling excess capacitance concept that defines the dependent current source for the anisotropic PEEC cell is defined and given for orthogonal PEEC meshes. As a result, the PEEC cell for an anisotropic dielectric is possible to extend to handle lossy and dispersive anisotropic dielectrics straightforwardly. The developed PEEC model has been applied to model a patch antenna mounted on an anisotropic substrate. The simulation results are in agreement with other simulation technique results. Consequently, the anisotropic model permits electromagnetic modeling of structures and devices that consist of a broader class of materials.

    The modeling of dielectrics in different ambient temperature conditions is also considered for the PEEC analysis of its impact on antennas. Dielectrics with temperature dependent permittivity have been modeled with PEEC by standard approaches found in the literature. This has proved useful for frequency-domain simulations in PEEC. The utility has been demonstrated by investigating the impact due to temperature-dependent dielectrics on printed antennas. These types of investigations could provide valuable in-formation in the design of printed antennas in harsh environments.

    Finally, the problem of designing magneto-dielectric materials that intrinsically provide distortionless propagation for TEM mode signals is investigated. The frequency dependent permittivity and permeability of a slab are related to the per-unit length (p.u.l.) parameters of a two-conductor transmission line. The p.u.l. parameters are specified to approximate the Heaviside condition in a specified and finite frequency interval, while simultaneously enforcing that the corresponding permittivity and permeability represent a passive material. Consequently, the passivity condition ensures the designed material is possible to realize in practice while the Heaviside condition secures that the material is distortionless. The design method has been employed to design a passive material that approximates the Heaviside condition in a narrow frequency interval. Verification in both time and frequency domains indicates that the designed material closely resembles a distortionless material in the specified frequency interval. These results indicate that an approximation of the Heaviside condition could be a potential aid in the design of distortionless materials for bandlimited applications. Further investigations on design method improvements, limitations on the approximation in terms of both accuracy and bandwidth, and the construction of such materials in practice could lead to new distortionless cable or material designs.

  • 29.
    Pamidi, Taraka Rama Krishna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Energy Efficient Fibrillation of Cellulose Fibers using an Ultrasound Reactor2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The pulp and paper industry is in continuous need for energy-efficient production processes. Therefore, there is a focus in reducing electrical energy use in the production of paper.  The most energy demanding processes are related to fibrillation, which in some cases use up to 80% of required electrical power, with a net efficiency of 1%. The presented work focus on ultrasound controlled cavitation in concentrating the processing energy to provide an energy efficient development of cellulose fibers. The objectives are to develop a scalable cavitation reactor to obtain energy-efficient fibrillation of cellulose fibers aiming at reducing the energy use by 50%. Our goal is to develop a methodology based on multiphysic simulation for the design of an alternative refiner based on ultrasound cavitation. The reactor concept is of a flow through type where cavitation bubbles are initiated in the fiber suspension by the pressure release when the pulp flow through a venturi nozzle. The induced cavitation bubbles are collapsed by high intensity ultrasound at resonant frequencies. The collapsing bubbles and their associated shock waves modify the fiber wall properties which enables fibrillation.  Energy efficient fibrillation of cellulose fibers is therefore possible to achieve through an optimized combination of hydrodynamic and ultrasonic controlled cavitation. Initial results shows a positive effect on fiber quality. However, further optimization of process parameters like temperature and static pressure is required.

  • 30.
    Onur, Tuğba Özge
    et al.
    Department of Electrical-Electronics Engineering, Bulent Ecevit University, Zonguldak, Turkey.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Svanström, Erika
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Estimation of the Propagation of Flexural Waves in Thin Plates Using a Single Low Cost Sensor2019Ingår i: Iranian Journal of Science and Technology, Transactions of Electrical Engineering, ISSN 2228-6179, Vol. 43, nr 3, s. 405-413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper demonstrates how flexural wave propagation in a thin plate can be modeled by estimating the combined effect of the excitation source signal and the impulse response of the ultrasonic sensor. The wave propagation in the plate is modeled using the wave equation for the flexural wave mode. A theoretical model for flexural wave propagation in thin plates has been derived, and it has been compared with measurements excited by tapping gently on the surface. The combined effects of the excitation source signal and the impulse response of the low-cost piezoelectric sensor are modeled using finite-impulse response and/or infinite-impulse response filters. Thereafter, the performances of the selected filters are compared on estimating the wave propagation in a thin quartz glass plate. Results indicate that the most accurate estimation of wave propagation has been obtained using a linear phase filter which attributes all dispersions to the flexural wave.

  • 31.
    Kovács, György
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. MTA-SZTE Research Group on Artificial Intelligence.
    Tóth, László
    Institute of Informatics, University of Szeged, Szeged, Hungary.
    Van Compernolle, Dirk
    Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Examining the combination of multi-band processing and channel dropout for robust speech recognition2019Ingår i: Proceedings of the Annual Conference of the International Speech Communication Association, 2019, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    A pivotal question in Automatic Speech Recognition (ASR) is the robustness of the trained models. In this study, we investigate the combination of two methods commonly applied to increase the robustness of ASR systems. On the one hand, inspired by auditory experiments and signal processing considerations, multi-band band processing has been used for decades to improve the noise robustness of speech recognition. On the other hand, dropout is a commonly used regularization technique to prevent overfitting by keeping the model from becoming over-reliant on a small set of neurons. We hypothesize that the careful combination of the two approaches would lead to increased robustness, by preventing the resulting model from over-rely on any given band. To verify our hypothesis, we investigate various approaches for the combination of the two methods using the Aurora-4 corpus. The results obtained corroborate our initial assumption, and show that the proper combination of the two techniques leads to increased robustness, and to significantly lower word error rates (WERs). Furthermore, we find that the accuracy scores attained here compare favourably to those reported recently on the clean training scenario of the Aurora-4 corpus.

  • 32.
    Dadhich, Siddharth
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Torbjörn
    Volvo CE, Bolindervägen 5, 63185 Eskilstuna, Sweden.
    Field test of neural-network based automatic bucket-filling algorithm for wheel-loaders2019Ingår i: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 97, s. 1-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Automation of earth-moving industries (construction, mining and quarry) require automatic bucket-filling algorithms for efficient operation of front-end loaders. Autonomous bucket-filling is an open problem since three decades due to difficulties in developing useful earth models (soil, gravel and rock) for automatic control. Operators make use of vision, sound and vestibular feedback to perform the bucket-filling operation with high productivity and fuel efficiency. In this paper, field experiments with a small time-delayed neural network (TDNN) implemented in the bucket control-loop of a Volvo L180H front-end loader filling medium coarse gravel are presented. The total delay time parameter of the TDNN is found to be an important hyperparameter due to the variable delay present in the hydraulics of the wheel-loader. The TDNN network successfully performs the bucket-filling operation after an initial period (100 examples) of imitation learning from an expert operator. The demonstrated solution show only 26% longer bucket-filling time, an improvement over manual tele-operation performance.

  • 33.
    Sharma, Vishal
    et al.
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore, India.
    Bisht, Pranshu
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore, India.
    Dalal, Abhishek
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore, India.
    Gopal, Maisagalla
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore, India.
    Vishvakarma, Santosh Kumar
    Nanoscale Devices, VLSI Circuit and System Design Lab, Department of Electrical Engineering, Indian Institute of Technology, Indore, India.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Half-select free bit-line sharing 12T SRAM with double-adjacent bits soft error correction and a reconfigurable FPGA for low-power applications2019Ingår i: AEU - International Journal of Electronics and Communications, ISSN 1434-8411, E-ISSN 1618-0399, Vol. 104, nr May, s. 10-22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work presents a half-select free 12T SRAM cell with Data-Dependent Feedback Cutting approach to improve the write ability and isolated read path to enhance the read stability. The enhanced read and write ability is 1.95×" role="presentation"> and 2.84×" role="presentation"> larger respectively than that of the conventional 6T cell at 0.4 V. The half-select free behavior of proposed cell using the cross-point read/write structure facilitates the bit-interleaving memory architecture to effectively reduce the multi-bits soft error occurrence. The incorporated PMOS stacking effect in inverter pairs of the proposed cell offers the reduced leakage power which is 0.59×" role="presentation"> to that of 6T, at 0.4 V supply. To further minimize the leakage power at array level, the bit lines between two adjacent cells have been shared that consumes only 0.38×" role="presentation"> leakage power than that of the conventional 6T array for a 1 KB macro. Moreover, a Reconfigurable FPGA architecture is proposed for low power applications. The simulated static and active power consumption of 12T SRAM based reconfigurable FPGA is 0.22×" role="presentation"> and 0.45×" role="presentation"> when compared with the regular 12T FPGA. Finally, a Double Adjacent-bits Error Detection and Correction (DAEDC) scheme is suggested for the proposed bit-interleaved 12T SRAM array, to reduce the soft error effects.

  • 34.
    Pondenkandath, Vinaychandran
    et al.
    University of Fribourg.
    Alberti, Michele
    University of Fribourg.
    Diatta, Michaël
    University of Fribourg.
    Ingold, Rolf
    University of Fribourg.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Historical Document Synthesis with Generative Adversarial Networks2019Ingår i: 2019 International Conference on Document Analysis and Recognition Workshops (ICDARW), IEEE, 2019, Vol. 5, s. 146-151Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This work tackles a particular image-to-image translation problem, where the goal is to transform an image from a source domain (modern printed electronic document) to a target domain (historical handwritten document). The main motivation of this task is to generate massive synthetic datasets of "historic" documents which can be used for the training of document analysis systems. By completing this task, it becomes possible to consider the generation of a tremendous amount of synthetic training data using only one single deep learning algorithm. Existing approaches for synthetic document generation rely on heuristics, or 2D and 3D geometric transformation-functions and are typically targeted at degrading the document. We tackle the problem of document synthesis and propose to train a particular form of Generative Adversarial Neural Networks, to learn a mapping function from an input image to an output image. With several experiments, we show that our algorithm generates an artificial historical document image that looks like a real historical document - for expert and non-expert eyes - by transferring the "historical style" to the classical electronic document.

  • 35.
    Saini, Rajkumar
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Dobson, Derek
    FamilySearch, USA.
    Morrey, Jon
    FamilySearch, USA.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Foteini
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    ICDAR 2019 Historical Document Reading Challenge on Large Structured Chinese Family Records2019Ingår i: ICDAR 2019: ICDAR 2019 HDRC Chinese, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a large historical database of Chinese family records with the aim to develop robust systems for historical document analysis. In this direction, we propose a Historical Document Reading Challenge on Large Chinese Structured Family Records (ICDAR 2019 HDRCCHINESE).The objective of the competition is to recognizeand analyze the layout, and finally detect and recognize thetextlines and characters of the large historical document image dataset containing more than 10000 pages. Cascade R-CNN, CRNN, and U-Net based architectures were trained to evaluatethe performances in these tasks. Error rate of 0.01 has been recorded for textline recognition (Task1) whereas a Jaccard Index of 99.54% has been recorded for layout analysis (Task2).The graph edit distance based total error ratio of 1.5% has been recorded for complete integrated textline detection andrecognition (Task3).

  • 36.
    Nilsson, Jacob
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Interoperability automation considered as machine learning tasks2019Konferensbidrag (Övrigt vetenskapligt)
  • 37.
    Paniagua, Cristina
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Interoperability Mismatch Challenges in Heterogeneous SOA-based Systems2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Industry 4.0, systems with a heterogeneous imple-mentation, different architecture, protocols, and semantics have to be integrated into collaborative environments. The interoper-ability between them has become a major challenge in this new ecosystem of the industry, thereby generating several research questions about how to manage the information exchange and collaboration between systems with so vastly different properties.This paper presents a detailed investigation of the different mismatch problems that can happen in the information ex-change in heterogeneous SOA-based environments where the interoperability is crucial. The proposed solution in this paper is an Adapter System that can aid generatation of new service consumer interfaces at both compile-time and run-time. The interfaces are based on Service Contracts, thereby allowing heterogeneous systems to communicate and interchange services.The proposed approach requires a new point of view in the service description field that can provide a holistic description of the information required for creating both run-time and compile-time consumer interfaces.

  • 38.
    Martin del Campo Barraza, Sergio
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Schnabel, Stephan
    Kinematic Frequencies of Rotating Equipment Identified with Sparse Coding and Dictionary Learning2019Ingår i: Proceedings of the Annual Conference of the Prognostics and Health Management Society 2019 / [ed] N. Scott Clements, Scottsdale, AZ, USA, 2019, Vol. 11Konferensbidrag (Refereegranskat)
    Abstract [en]

    The detection of faults and operational abnormalities in rotating machine elements like rolling element bearings and gears requires information about kinematic properties, such as ball-pass and gear mesh frequencies. Typically, condition monitoring experts obtain such information from the manufacturers for diagnostics purposes. However, the reliability of such information can be compromised during installation and maintenance, for example, if components are replaced and do not match the documented specifications. Thus, methods enabling verification and online extraction of such kinematic properties are needed to improve diagnostic reliability. Unsupervised machine learning methods, like sparse coding with dictionary learning, enable automatic modeling and characterization of repeating signal structures in the time domain, which are naturally generated by rotating equipment. Sparse coding with dictionary learning represents a vibration signal as a linear superposition of noise and atomic waveforms. The activation rate of the atomic waveforms typically possesses a cyclic nature in rotating environments, similar to how bearing kinematic frequencies correlate with faults in a rolling element bearing. However, there is no explicit relationship between the activation rates of the atoms and the bearing kinematic frequencies. This motivates this investigation of the possibility to extract bearing kinematic frequencies from sparse representations. Former work describes the use of dictionary learning for the detection of anomalies in rolling element bearings. In this paper, we describe how a similar unsupervised machine learning method can be used to extract kinematic frequencies of bearings and gears, for example for anomaly detection purposes and comparisons with an expected signature. We study the activation rates and changes of atoms learned from vibration signals in two case studies. The first case is based on data from a well-known controlled experiment with faults seeded in the bearings. The second case is based on a public dataset recorded from the high-speed shaft of a wind turbine with a bearing failure. Furthermore, we compare the activation rates and weights of the atoms to the bearing kinematic frequencies and harmonics. Sparse coding with dictionary learning offers a possibility for self-learningof the kinematic frequencies of a bearing, which can be useful for the further improvement of automated anomaly detection methods in condition monitoring.

  • 39.
    Karvonen, Niklas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nilsson, Joakim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kleyko, Denis
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Jimenez, Lara Lorna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Low-Power Classification using FPGA: An Approach based on Cellular Automata, Neural Networks, and Hyperdimensional Computing2019Ingår i: 2019 18th IEEE International Conference On Machine Learning And Applications (ICMLA) / [ed] M. Arif Wani, Taghi M. Khoshgoftaar, Dingding Wang, Huanjing Wang, Naeem (Jim) Seliya, IEEE, 2019, s. 370-375Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Field-Programmable Gate Arrays (FPGA) are hardware components that hold several desirable properties for wearable and Internet of Things (IoT) devices. They offer hardware implementations of algorithms using parallel computing, which can be used to increase battery life or achieve short response-times. Further, they are re-programmable and can be made small, power-efficient and inexpensive. In this paper we propose a classifier targeted specifically for implementation on FPGAs by using principles from hyperdimensional computing and cellular automata. The proposed algorithm is shown to perform on par with Naive Bayes for two benchmark datasets while also being robust to noise. It is also synthesized to a commercially available off-the-shelf FPGA reaching over 57.1 million classifications per second for a 3-class problem using 40 input features of 8 bits each. The results in this paper show that the proposed classifier could be a viable option for applications demanding low power-consumption, fast real-time responses, or a robustness against post-training noise.

  • 40.
    Nilsson, Joakim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Imperial Coll, Dept Phys, London SW7 2AZ, England.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Maximal Q Factor for an On-Chip, Fuse-Based Trimmable Capacitor2019Ingår i: Electronics, ISSN 2079-9292, Vol. 8, nr 1, artikel-id 62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a circuit for realising a fuse-programmable capacitor on-chip. The trimming mechanism is implemented using integrated circuit fuses which can be blown in order to lower the resulting equivalent capacitance. However, for integrated circuits, the non-zero fuse resistance for active fuses and finite fuse resistance for blown fuses limit the Q factor of the resulting capacitor. In this work, we present a method on how to arrange the fuses in order to achieve maximal worst-case Q factor for the given circuit topology given the process parameters and requirements on capacitance. We also analyse and discuss the accuracy and limitations of the topology with regard to fuse resistance and parasitic elements such as bond pads.

  • 41.
    Albertsson, Kim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. CERN.
    Gleyze, Sergei
    University of Florida.
    Huwiler, Marc
    EPFL.
    Ilievski, Vladimir
    EPFL.
    Moneta, Lorenzo
    CERN.
    Shekar, Saurav
    ETH Zurich.
    Estrade, Victor
    CERN.
    Vashistha, Akshay
    CERN. Karlsruhe Institute of Technology.
    Wunsch, Stefan
    CERN. Karlsruhe Institute of Technology.
    Mesa, Omar Andres Zapata
    University of Antioquia. Metropolitan Institute of Technology.
    New Machine Learning Developments in ROOT/TMVA2019Ingår i: 23rd International Conference on Computing in High Energy and Nuclear Physics (CHEP 2018), EDP Sciences, 2019, Vol. 214, artikel-id 06014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Toolkit for Multivariate Analysis, TMVA, the machine learning package integrated into the ROOT data analysis framework, has recently seen improvements to its deep learning module, parallelisation of multivariate methods and cross validation. Performance benchmarks on datasets from high-energy physics are presented with a particular focus on the new deep learning module which contains robust fully-connected, convolutional and recurrent deep neural networks implemented on CPU and GPU architectures. Both dense and convo-lutional layers are shown to be competitive on small-scale networks suitable for high-level physics analyses in both training and in single-event evaluation. Par-allelisation efforts show an asymptotical 3-fold reduction in boosted decision tree training time while the cross validation implementation shows significant speed up with parallel fold evaluation.

  • 42.
    Antonini, Giulio
    et al.
    University of L'Aquila (Italy).
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Miroshnikova, Elena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    On the passivity of the Delay-Rational Green’s-function-based model for Transmission Lines2019Ingår i: Analysis, Probability, Applications, and Computation: Proceedings of the 11th ISAAC Congress / [ed] Karl‐Olof Lindahl,Torsten Lindström, Luigi G. Rodino, Joachim Toft, Patrik Wahlberg, 2019, s. 71-81Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study the delay-rational Green’s-function-based (DeRaG) model for transmission lines. This model is described in terms of impedance representation and it contains a rational and a hyperbolic part. The crucial property of transmission lines models is to be passive. The passivity of the rational part has been studied by the authors in a previous work. Here, we extend the results to the rational part of the DeRaG model. Moreover, we prove the passivity of the hyperbolic part. 

  • 43.
    Romano, Daniele
    et al.
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, L’Aquila, Italy .
    Kovačević-Badstübner, Ivana
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich, Switzerland.
    Parise, Mauro
    Unit of Electrical Engineering, University Campus Bio-Medico of Rome, Rome, Italy.
    Grossner, Ulrike
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich, Switzerland.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, L’Aquila, Italy.
    Rigorous dc Solution of Partial Element Equivalent Circuit Models Including Conductive, Dielectric, and Magnetic Materials2019Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a rigorous derivation of the dc solution of three-dimensional partial element equivalent circuit (PEEC) formulation extended to include simultaneously conductive, dielectric, and magnetic materials. The circuit interpretation of Maxwell’s equations provided by the PEEC method allows to reformulate the dc modeling task in such a way that physical phenomena are fully exploited. Indeed, since the displacements currents are identically zero in dielectrics, Kirchhoff’s current law is enforced in terms of charge conservation internally to dielectrics or at the interface between dielectrics and other materials. A well-posed problem is achieved by adding the charges as new unknowns and identifying the disconnected objects. Two numerical examples are presented demonstrating the accuracy of the proposed method when compared to the dc solution as extracted by the fast Fourier transform of the impulse response and a finite element method simulation.

  • 44.
    Acharya, Sarthak
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Chouhan, Shailesh Singh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Scalability of Copper-Interconnects down to 3μm on Printed Boards by Laser-assisted-subtractive process2019Ingår i: Proceedings of: 2019 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), IEEE, 2019, s. 206-209Konferensbidrag (Refereegranskat)
    Abstract [en]

    As per the latest roadmap of iNEMI, the global electronics market is emphasizing to identify disruptive technologies that can contribute towards denser, robust and tighter integration on the board level. Therefore, reduction in packaging factor of printed board can accommodate greater number of ICs to support miniaturization. This paper has shown an experimental method to pattern the metallic layer on a Printed circuit Board (PCB) to the smallest feature size. To investigate this, a commercially available FR-4 PCB with photosensitive material coat and a Copper (Cu) layer on it, is used. A reverse-mode Laser assisted writing is implemented to pattern the desired copper tracks. Soon after, a well-controlled development and chemical etching of the Laser-activated regions are done using Sodium Hydroxide solution followed by an aqueous solution of Sodium Persulfate. Current PCB interconnects used by the industries are of the order (~20 μm). Whereas the present work is a contribution towards achieving Copper interconnects with feature size 3.0μm. This miniaturization corresponds to 70% reduction in the feature size from 20 μm to 3μm. The natural adhesion of the Cu layer has remained intact even after the etching, shows the efficiency of the method adopted. Also, variation in the parameters such as etching time, etchant solution concentrations, temaperature, gain and exposure time of Laser beam and their corresponding effects are discussed. Other highlights of this subtractive method includes its cost-efficiency, lesser production time and repeatability.

  • 45.
    Nilsson, Mattias
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Spatiotemporal Pattern Recognition with Neuromorphic Processor for Edge Applications2019Ingår i: Online Proceedings of SAIS 2019, 2019Konferensbidrag (Refereegranskat)
  • 46. Shridhar, Kumar
    et al.
    Dash, Ayushman
    Sahu, Amit
    Grund Pihlgren, Gustav
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Alonso, Pedro
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pondenkandath, Vinaychandran
    Kovács, G
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Simistira Liwicki, Foteini
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Subword Semantic Hashing for Intent Classification on Small Datasets2019Ingår i: 2019 International Joint Conference on Neural Networks (IJCNN), 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    n this paper, we introduce the use of Semantic Hashing as embedding for the task of Intent Classification and achieve state-of-the-art performance on three frequently used benchmarks. Intent Classification on a small dataset is a challenging task for data-hungry state-of-the-art Deep Learning based systems. Semantic Hashing is an attempt to overcome such a challenge and learn robust text classification. Current word embedding based methods [11], [13], [14] are dependent on vocabularies. One of the major drawbacks of such methods is out-of-vocabulary terms, especially when having small training datasets and using a wider vocabulary. This is the case in Intent Classification for chatbots, where typically small datasets are extracted from internet communication. Two problems arise with the use of internet communication. First, such datasets miss a lot of terms in the vocabulary to use word embeddings efficiently. Second, users frequently make spelling errors. Typically, the models for intent classification are not trained with spelling errors and it is difficult to think about ways in which users will make mistakes. Models depending on a word vocabulary will always face such issues. An ideal classifier should handle spelling errors inherently. With Semantic Hashing, we overcome these challenges and achieve state-of-the-art results on three datasets: Chatbot, Ask Ubuntu, and Web Applications [3]. Our benchmarks are available online.

  • 47.
    Palm, Emanuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Paniagua, Cristina
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Syntactic Translation of Message Payloads Between At Least Partially Equivalent Encodings2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recent years have seen a surge of interest in using IoT systems for an increasingly diverse set of applications, with use cases ranging from medicine to mining. Due to the disparate needs of these applications, vendors are adopting a growing number of messaging protocols, encodings and semantics, which result in poor interoperability unless systems are explicitly designed to work together. Key efforts, such as Industry 4.0, put heavy emphasis on being able to compose arbitrary IoT systems to create emergent applications, which makes mitigating this barrier to interoperability a significant objective. In this paper, we present a theoretical method for translating message payloads in transit between endpoints, complementing previous work on protocol translation. The method involves representing and analyzing encoding syntaxes with the aim of identifying the concrete translations that can be performed without risk of syntactic data loss. While the method does not facilitate translation between all possible encodings or semantics, we believe that it could be extended to enable such translation.

  • 48.
    Derhamy, Hasan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    System of System Composition based on Decentralized Service Oriented Architecture2019Ingår i: IEEE Systems Journal, ISSN 1932-8184, E-ISSN 1937-9234, Vol. 13, nr 4, s. 3675-3686Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As society has progressed through periods of evolution and revolution, technology has played a key role as an enabler. In the same manner, mechanical machines of the 1800s drove the industrial revolution, now digitalized machines are driving another industrial revolution. Manufacturers are increasing the digital footprint on the factory floor. It is challenging to harness the vast amounts of data generated, stored, analyzed, archived, and returned. Data centralization has several well-known challenges, such as collection bottlenecks, secure retrieval, single point of failure, and data scheme fragility as data heterogeneity increases. This paper proposes a method of information distribution based on the principle of data at its source . It proposes that contextual data be used at runtime through the creation of dynamic queries that build compositions of different systems. Such system of systems (SoS) compositions handle the flow of data across its life cycle and present it as information to the initiating system. The proposal starts by creating a graph model of the Arrowhead framework. Then, building on the graph model, the query-based approach for specifying, validating, and forming the SoS is proposed. The proposed graph model allows for unambiguous description of systems and their interrelations, including security relations. The proposed composer operates on the edge computing hardware and gives the production floor the ability to extract information without impacting the overall operation of the factory.

  • 49.
    Paniagua, Cristina
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Luleå University of technology (Sweden).
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik. Luleå University of technology (Sweden).
    Hegedus, Csaba
    AITIA International Inc. Budapest, Hungary.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik. Luleå University of technology (Sweden).
    System of Systems integration via a structurednaming convention2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    During the last decade, technology changes and digitization have introduced numerous improvements and challenges in multiple areas of the industry, automation, and design of new architecture. However, the definitions of new naming conventions and identifiers that can be adapted to the new paradigm have not yet been considered.This paper analyzes aspects and characteristics that have to be included in the design of a naming convention consistent with the current Industry 4.0 requirements. As a result, this paper proposes a new naming convention for the Arrowhead Framework following the requisites and characteristics defined in the system of systems (SoS) integration.The proposed Arrowhead naming convention represents a renovated vision of the identification of services, systems, devices, and networks. A powerful tool in the quest of interoperability, security, service discovery, topology, and dynamic orchestration, as well as, a structured manner of defining meaningfully identifiers as help for developers

  • 50.
    Nilsson, Jacob
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    System of Systems Interoperability Machine Learning Model2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Increasingly flexible and efficient industrial processes and automation systems are developed by integrating computational systems and physical processes, thereby forming large heterogeneous systems of cyber-physical systems. Such systems depend on particular data models and payload formats for communication, and making different entities interoperable is a challenging problem that drives the engineering costs and time to deployment. Interoperability is typically established and maintained manually using domain knowledge and tools for processing and visualization of symbolic metadata, which limits the scalability of the present approach. The vision of next generation automation frameworks, like the Arrowhead Framework, is to provide autonomous interoperability solutions. In this thesis the problem to automatically establish interoperability between cyber-physical systems is reviewed and formulated as a mathematical optimisation problem, where symbolic metadata and message payloads are combined with machine learning methods to enable message translation and improve system of systems utility. An autoencoder based implementation of the model is investigated and simulation results for a heating and ventilation system are presented, where messages are partially translated correctly by semantic interpolation and generalisation of the latent representations. A maximum translation accuracy of 49% is obtained using this unsupervised learning approach. Further work is required to improve the translation accuracy, in particular by further exploiting metadata in the model architecture and autoencoder training protocol, and by considering more advanced regularization methods and utility optimization.

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