SwePub - sökning: WFRF:(Bengtsson Lars 1963)

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1.	Bohlin, Robert, 1972, et al. (författare) Data Flow and Communication Framework Supporting Digital Twin for Geometry Assurance 2018 Ingår i: ASME 2017 International Mechanical Engineering Congress and Exposition. ; 2 Konferensbidrag (refereegranskat)abstract Faster optimization algorithms, increased computer power and amount of available data, can leverage the area of simulation towards real-time control and optimization of products and production systems. This concept — often referred to as Digital Twin — enables real-time geometry assurance and allows moving from mass production to more individualized production. To master the challenges of a Digital Twin for Geometry Assurance the project Smart Assembly 4.0 gathers Swedish researchers within product development, automation, virtual manufacturing, control theory, data analysis and machine learning. The vision of Smart Assembly 4.0 is the autonomous, self-optimizing robotized assembly factory, which maximizes quality and throughput, while keeping flexibility and reducing cost, by a sensing, thinking and acting strategy. The concept is based on active part matching and self-adjusting equipment which improves geometric quality without tightening the tolerances of incoming parts. The goal is to assemble products with higher quality than the incoming parts. The concept utilizes information about individual parts to be joined (sensing), selects the best combination of parts (thinking) and adjust locator positions, clamps, weld/rivet positions and sequences (acting). The project is ongoing, and this paper specifies and highlights the infrastructure, components and data flows necessary in the Digital Twin in order to realize Smart Assembly 4.0. The framework is generic, but the paper focuses on a spot weld station where two robots join two sheet metal parts in an adjustable fixture.
2.	Magnusson, Maria K, 1972, et al. (författare) Macrophage and dendritic cell subsets in IBD: ALDH cells are reduced in colon tissue of patients with ulcerative colitis regardless of inflammation 2016 Ingår i: Mucosal Immunology. - : Elsevier BV. - 1935-3456 .- 1935-3456 .- 1933-0219. ; 9:1, s. 171-182 Tidskriftsartikel (refereegranskat)abstract Disruption of the homeostatic balance of intestinal dendritic cells (DCs) and macrophages (MQs) may contribute to inflammatory bowel disease. We characterized DC and MQ populations, including their ability to produce retinoic acid, in clinical material encompassing Crohn's ileitis, Crohn's colitis and ulcerative colitis (UC) as well as mesenteric lymph nodes (MLNs) draining these sites. Increased CD14+DRint MQs characterized inflamed intestinal mucosa while total CD141+ or CD1c+ DCs numbers were unchanged. However, CD103+ DCs, including CD141+CD103+ and CD1c+CD103+ DCs, were reduced in inflamed intestine. In MLNs, two CD14- DC populations were identified: CD11cintHLADRhi and CD11chiHLADRint cells. A marked increase of CD11chiHLADRint DC, particularly DRintCD1c+ DCs, characterized MLNs draining inflamed intestine. The fraction of DC and MQ populations expressing aldehyde dehydrogenase (ALDH) activity, reflecting retinoic acid synthesis, in UC colon, both in active disease and remission, were reduced compared to controls and inflamed Crohn's colon. In contrast, no difference in the frequency of ALDH+ cells among blood precursors was detected between UC patients and non-inflamed controls. This suggests that ALDH activity in myeloid cells in the colon of UC patients, regardless of whether the disease is active or in remission, is influenced by the intestinal environment.
3.	Aaboen, Lise, 1978, et al. (författare) Nourishment for the piggy bank : facilitation of external financing in incubators 2011 Ingår i: International Journal of Technology Transfer and Commercialisation. - : Inderscience. - 1470-6075 .- 1741-5284. ; 10 3-4, s. 354-374 Tidskriftsartikel (refereegranskat)abstract In this paper, we argue that incubators facilitate access to external financing for their incubatees. Incubators use a wide range of activities to facilitate the accessing of external financing from public and private sources. We have grouped these into two sets of activities. The general activities aim to develop the conditions for external financing through information, education of incubatees, network-building and lobbying activities. The specific activities aim to assist the individual incubatee in their pursuit of external finance through help in application procedures, establishing need for capital, making contacts with the best public or private investor, etc. Based on the survey data, we have also shown that it is more common for incubatees to attract external capital compared to non-incubator firms. The incubatees seem especially successful in attracting public capital. The incubatees also attract more private external capital, however, the observed frequency of private capital in the incubatees are low.
4.	Ahrenberg, Lars, 1948-, et al. (författare) Studying Disability Related Terms with Swe-Clarin Resources 2019 Konferensbidrag (refereegranskat)abstract In Swedish, as in other languages, the words used to refer to disabilities and people with disabilities are manifold. Recommendations as to which terms to use have been changed several times over the last hundred years. In this exploratory paper we have used textual resources provided by Swe-Clarin to study such changes quantitatively. We demonstrate that old and new recommendations co-exist for long periods of time, and that usage sometimes converges.
5.	Bengtsson, Jonas, 1961, et al. (författare) Can a failed ileal pouch anal anastomosis be left in situ? 2007 Ingår i: Colorectal disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 9:6, s. 503-8 Tidskriftsartikel (refereegranskat)abstract OBJECTIVE: Failure after ileal pouch-anal anastomosis (IPAA) is reported with a frequency of 10-20%. The failed IPAA can be excised or defunctioned. Indications for excision and further management of an indefinitely diverted pouch are poorly described. The aim of the present investigation was to investigate pouch-related problems and the histopathological pattern of the pouch mucosa in this group of patients. METHOD: In a cohort of 620 patients having IPAA with a median follow-up of 14 years, 56 patients with failure were identified. The patients with defunctioned pouches were assessed with regard to pouch-related problems and endoscopy with biopsies was performed. Biopsies were stained with haematoxylin-eosin, PAS for neutral mucins and Alcian blue/high iron diamine for sialomucins/sulphomucins. Morphological changes were grouped into three types modified according to Veress and assessed for dysplasia. RESULTS: Twenty-two patients with an indefinitely diverted pouch were found. The follow-up time after surgery for failure was 10 years. Thirteen patients completed the follow-up. Except for two patients with pelvic/perineal pain, there were no clinical problems. The majority of patients displayed mild to moderate macroscopic signs of inflammation. Morphologically, findings ranged from a preserved mucosal pattern to intense inflammatory reaction. No case of dysplasia or carcinoma was found. CONCLUSION: Most patients with an indefinitely diverted pouch had no complaints regarding the pouch. There was no case of dysplasia. Indefinite diversion may be preferable to pouch excision, especially given the associated morbidity.
6.	Bengtsson, Jonas, 1961, et al. (författare) Long-term function and manovolumetric characteristics after ileal pouch-anal anastomosis for ulcerative colitis 2007 Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 94:3, s. 327-32 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: Long-term pouch function and physiological characteristics after ileal pouch-anal anastomosis (IPAA) are poorly described. The aim of this study was to undertake a prospective investigation of long-term pouch function and manovolumetric characteristics. METHODS: Forty-two patients with a median follow-up of 16 years after IPAA were included. Function was assessed using a questionnaire and a score was calculated ranging from 0 to 15 (15 being the worst). Manovolumetry was performed and pouchitis recorded. A paired analysis was conducted, as the results were compared with previous data for each patient. RESULTS: The median functional score was 3.5 (range 0-10) at 2 years and 5 (range 1-11) at 16 years (P = 0.013). Resting anal canal pressures were higher (P < 0.001) and squeeze pressures lower (P = 0.008) at long-term follow-up. Ileal pouch volumes at distension pressures of 10, 20 and 40 cm H(2)O were diminished at 16 years (P < 0.001, P = 0.005 and P = 0.058 respectively). The volume and pressure for first sensation and urge to defaecate were reduced. Increased age correlated positively with a poor functional score. A history of pouchitis did not affect functional or physiological characteristics. CONCLUSION: Ileal pouch function declines in the long term. The reasons are unclear, but the ageing process may have an impact.
7.	Bengtsson, Lars, 1963 (författare) 24-channel dual microcontroller-based voltage controller for ion optics remote control 2018 Ingår i: Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 890, s. 96-101 Tidskriftsartikel (refereegranskat)abstract The design of a 24-channel voltage control instrument for Wenzel Elektronik N1130 NIM modules is described. This instrument is remote controlled from a LabVIEW GUI on a host Windows computer and is intended for ion optics control in electron affinity measurements on negative ions at the CERN-ISOLDE facility. Each channel has a resolution of 12 bits and has a normally distributed noise with a standard deviation of <1 mV. The instrument is designed as a standard 2-unit NIM module where the electronic hardware consists of a printed circuit board with two asynchronously operating microcontrollers.
8.	Bengtsson, Lars, 1963 (författare) A microcontroller-based lock-in amplifier for sub-milliohm resistance measurements 2012 Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 83:7 Tidskriftsartikel (refereegranskat)abstract This paper presents a novel approach to the design of a digital ohmmeter with a resolution of <60 μΩ based on a general-purpose microcontroller and a high-impedance instrumentation amplifier only. The design uses two digital I/O-pins to alternate the current through the sample resistor and combined with a proper firmware routine, the design is a lock-in detector that discriminates any signal that is out of phase/frequency with the reference signal. This makes it possible to selectively detect the μV drop across sample resistors down to 55.6 μΩ using only the current that can be supplied by the digital output pins of a microcontroller. This is achieved without the need for an external reference signal generator and does not rely on the computing processing power of a digital signal processor.
9.	Bengtsson, Lars, 1963 (författare) An Ion Beam Guidance Control Tool 2019 Ingår i: Proceedings of the 5th International Conference on Sensors and Electronic Instrumentation Advances. - : International Frequency Sensor Association (IFSA) Publishing. - 9788409144136 Konferensbidrag (refereegranskat)abstract A versatile tool for ion beam line up is proposed. This tool will be used at the CERN-ISOLDE facility in negative ion experiments. Apertures in the ion optics are used to guide the beam and traditionally the current is measured on the apertures in order to detect the presence of an ion beam. By slitting the aperture into four separate pieces, the aperture current can also be used to determine the direction of the misalignment and the size of the ion beam diameter. A 4-channel pico ammeter with optical LED indication of the ion beam position is suggested in an analog/digital hybrid design. The design utilizes two charge/current-to-digital chips in a microcontroller design.
10.	Bengtsson, Lars, 1963 (författare) Analysis of Direct Sensor-to-Embedded Systems Interfacing: A Comparison of Target's Performance 2012 Ingår i: International Journal of Intelligent Mechatronics and Robotics. - : IGI Global. - 2156-1664 .- 2156-1656. ; 2:1, s. 41-56 Tidskriftsartikel (refereegranskat)abstract This paper is concerned with the direct interfacing of resistive sensors to different embedded targets. We use the idea of “direct sensor-to-microcontroller” technique where analog sensors are interfaced directly to inherently digital controllers and we compare the performance of this technique when applied to a typical microcontroller (PIC18), a CPLD and an FPGA. Experimental results show that 5 V systems, like the PIC18 controller, have an advantage over 3.3 V systems in terms of better precision performance, while the CPLD outperforms both the microcontroller and the FPGA in terms of accuracy. The accuracy depends mainly on the output impedance of the system’s I/O ports and the precision depends mainly on trigger level noise. The PIC18 controller also has the best performance in terms of linearity and sensitivity. A lot of works have been published concerning direct interfacing to microcontrollers, but little attention has been paid to alternative targets like CPLD and FPGA. This work will benchmark these different kinds of targets and prove that the direct interfacing technique can also be applied to CPLDs and FPGAs.
11.	Bengtsson, Lars, 1963 (författare) Atomic laser resonance ionization mass spectrometry 1990 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)
12.	Bengtsson, Lars, 1963 (författare) Avancerad Elektrisk Mätteknik 1996 Bok (övrigt vetenskapligt/konstnärligt)abstract Boken är avsedd för fortsättnigskurser i elektrisk mätteknik på högskolenivå. Den lämpar sig också väl som kompletteringslitteratur för kurser i signalbehandling. Innehållet är framför allt koncentrerat till analog och digital frekvensanalys, brusreducerande mätmetoder och AD/DA-omvandlingsmetoder. Ett kapitel tar upp signalbehandling och sambanden mellan analys i tid och rum. Fouriertransformen och faltningsintegralen gås igenom i detalj. Boken avslutas dels med ett kapitel om snabba förlopp i transmissionsledningar, dels med ett kapitel om GPIB-bussen. I appendix finns även en beskrivning av RS-232-kommunikation.
13.	Bengtsson, Lars, 1963 (författare) Direct analog-to-microcontroller interfacing 2012 Ingår i: Sensors and Actuators A. - : Elsevier BV. - 0924-4247. ; A 179, s. 105-113 Tidskriftsartikel (refereegranskat)abstract This paper will demonstrate how signals from analog sensors can be directly interfaced to any digital embedded system even though they may not be equipped with an on-chip ADC (Analog-to-Digital Converter), comparator or OP amp (Operational Amplifier). With only two resistors and one capacitor, we will present a solution that allows analog voltages to be measured directly using only a few digital I/O-pins. The digital target system requirements are minimized and limited to only two digital I/O-pins (with tristate capability). No ADC, comparators, timers or capture modules are necessary. The extremely modest hardware requirements make it a suitable solution also for CPLDs/FPGAs (Complex Programmable Logic devices/Field Programmable Gate Arrays). Since this solution will allow even the simplest embedded system to be interfaced to analog voltage sensors, it has the potential of reducing design costs considerably. The proposed design is for DC or low-frequency signals and compared to other similar solution, this design needs no embedded analog blocks at all.
14.	Bengtsson, Lars, 1963 (författare) Electrical interferences in electrical measurement systems demystified 2012 Ingår i: International Journal of Electrical Engineering Education. - 0020-7209. ; 49:2, s. 101-113 Tidskriftsartikel (refereegranskat)abstract This paper is concerned with the practical aspects of protecting an electrical measurement system against different kinds of interfering cross-talk. We categorize different kinds of cross-talk, describe their origin and how to decoupled them in order to protect the system. This presentation is a primer for students or application engineers concerned with the practical operation of an electrical measurement system. We explain cross-talk phenomena with a minimum of electromagnetic theory, focusing more on understanding the origin of cross-talk in terms of basic electric and magnetic circuits rather than advanced electromagnetic wave equations, and how to decouple them. Compared to a typical textbook presentation on the subject, this work categorizes all kinds of electromagnetic interferences (EMI), using a minimum of mathematic equations, and clearly explain their origin and illustrates clearly how each one is decoupled.
15.	Bengtsson, Lars, 1963 (författare) Electrical Measurement Systems and Methods 2014 Bok (övrigt vetenskapligt/konstnärligt)abstract This book treats a wide range of aspects on electrical measurement systems and the methods used to acquire data from electronic systems. That includes sensors and sensor design, amplifiers such as differential and charge amplifiers, ADCs and DACs, digital oscilloscopes, cable theory and probes, noise and noise coupling, common and normal mode signals. This first part (chapters 1-8) doesn’t require any advanced mathematics and is aimed towards undergraduates. The second part (chapters 9-17) is on an advanced level (master level) and treats transform theory (Fourier, Laplace, z) and how to handle signals in frequency space. We cover the sampling theorem (Nyquist), resolution bandwidth, frequency spectrum distortions like aliasing and leakage and how to apply windows in a frequency spectrum. We also cover systems and signal processing in time-space, including convolution and correlation, filter theory and filter design (both analog and digital). The last chapters concern the statistical aspects on measurement systems and signals, like point and interval estimations, curve fitting and uncertainty estimations according to the GUM method.
16.	Bengtsson, Lars, 1963 (författare) Electrical Measurement Techniques : For the physics laboratory 2024 Bok (övrigt vetenskapligt/konstnärligt)abstract This book highlights electrical engineering aspects of at typical physics laboratory. To perform a sound experiment in a physics laboratory, it is paramount that readers understand the equipment and methods used to collect the data. This includes sensors (e.g. thermocouples and vacuum gauges) amplifiers (e.g. instrumentation amplifiers and lock-in amplifiers), oscilloscopes and probes (active probes and current probes), transmission cables (50-ohm termination) and noise shielding (grounding), spectrum analyzers (FFT and heterodyne technique), ADCs and digital signal processing, convolution and correlation, data analysis such as curve fitting, and uncertainty calculations (uncertainty 'budgets'). The readers need to know about electromagnetic crosstalk, time-to-digital converters, student-t distributions, PID controllers, spectral leakage and windows. This book helps readers understand all of that.
17.	Bengtsson, Lars, 1963 (författare) Elektriska Mätsystem och Mätmetoder 2012 Bok (övrigt vetenskapligt/konstnärligt)abstract Behandlar elektrisk mätteknik, både teoretiskt och praktiskt. Del 1 innehåller t ex givare, förstärkare, AD-DA-omvandlare, digitala oscilloskop, ledningsteori ochstörningskoppling. Del 2, innehåller transformteori, frekvensanalys, sampling, vikning, läckage, filterteori och korrelation, punkt- och intervallskattning samt osäkerhetsanalys med en så kallade GUM-metoden.
18.	Bengtsson, Lars, 1963 (författare) Elektriska mätsystem och mätmetoder 2003 Bok (övrigt vetenskapligt/konstnärligt)abstract Elektrisk mätteknik spänner över ett brett teknikområde och har utvecklats till något av ett tvärtekniskt ingenjörsämne. Den här boken tar fasta på detta och behandlar en lång rad aspekter på elektriska mätsystem och mätmetoder. Boken innehåller t ex en detaljerad genomgång av givare, förstärkare och AD-omvandlare. Mätinstrument med inbyggda signalbehandlingsfunktioner som t ex frekvensanalys, korrelation och medelvärdesbildning utgör en stor del av innehållet. Även filter, både analoga och digitala behandlas. Mätinstrumentens och anslutningskablarnas inverkan på mätvärdet behandlas detaljerat liksom elektromagnetisk störningskoppling och EMC-aspekter på mätsystem, smat databehandling i form av mätosäkerhetsanalyser och kurvanpassning. I boken finns också en presentation av det grafiska programspråket LabVIEW.
19.	Bengtsson, Lars, 1963 (författare) Elektriska mätsystem och mätmetoder : Lösniingar 2001 Bok (övrigt vetenskapligt/konstnärligt)abstract Kompletta lösningar till övningsuppgifterna i boken "Elektriska mätsystem och mätmetoder".
20.	Bengtsson, Lars, 1963 (författare) Elektronikkonstruktion 2018 Bok (övrigt vetenskapligt/konstnärligt)abstract Boken beskriver framställning av kretskort, vilket inkluderar schemaritning, routning, generering av prduktionsfiler, beställning, lödning, test och verifiering.
21.	Bengtsson, Lars, 1963 (författare) Embedded FPGA systems : VHDL programming and soft CPU systems 2018 Bok (övrigt vetenskapligt/konstnärligt)abstract This textbook introduces the reader to VHDL which is a Hardware Description Language, i.e. a means to describe digital electronic circuits in a text editor and how to compile this text into electronics. The first part is concluded by writing VHDL code for a simple CPU (a "soft CPU"). In the second part, a commercial soft CPU is downloaded to the FPGA target circuit and programmed in C.
22.	Bengtsson, Lars, 1963 (författare) Embedded Measurement Systems 2013 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The subject of Embedded Measurement Systems (EMS) is the merging of embedded systems and electrical measurement systems. This indicates that EMSs are hardware-software systems dedicated to measuring one or a few physical quantities. Applications are numerous; EMSs measure the temperature in refrigerators, freezers, irons, ovens and automobile combustion engines, they sense vibrations in tilt alarms and game consoles, they measure airflow in engines and ventilation systems, they measure shock impact in crash detectors and are used as shock and temperature loggers for transport goods, they measure air pressure in airplane cabins, humidity in air-conditioned environments, they measure liquid levels in fuel tanks, they detect smoke in fire alarms, they measure the viscosity of lubricant oil in engines, they measure the rotation speed of spinning wheels (in any engine), they measure torque in engines and are used as heart rate and ECG detectors in medicine etc. The commercial demand for ever cheaper products and worldwide environmental legislations force vendors to continuously look for more cost-efficient and less power-consuming solutions for their embedded measurement systems. This thesis is concerned most of all with the implementation of cost-efficient/low-power measurement systems in embedded controllers. This includes some novel ideas in voltage, time and resistance measurements with embedded controllers and it will demonstrate how these quantities, analog in nature, can be measured accurately and precisely by inherently digital embedded controllers.
23.	Bengtsson, Lars, 1963 (författare) Embedded Vernier TDC with sub-nano second resolution using fractional-N PLL 2017 Ingår i: Measurement. - : Elsevier BV. - 0263-2241. ; 108, s. 48-54 Tidskriftsartikel (refereegranskat)abstract A novel implementation technique for Vernier-based time-to-digital converters is reported. It is based on fractional-N phase-locked loops which allows the design of Vernier clocks with very close frequencies. The Vernier registers comparing counter values have been implemented in hardware in order to guarantee minimum detection latency of the moment of coincidence. Two Vernier clocks with close frequencies increment two 24-bit counters in a Cyclone V FPGA. A Vernier TDC with a demonstrated time resolution of 476 ps is reported. It is also established that the time resolution limit that can be achieved with the suggested design is 10 ps.
24.	Bengtsson, Lars, 1963 (författare) Generation and measurement of pulses and delays with RISC-controllers 1997 Ingår i: Measurement Science and Technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 8, s. 679-683 Tidskriftsartikel (refereegranskat)abstract An instrument for the generation of pulses and delays has beendeveloped for applications in laserspectroscopy experiments. The pulses from achopped laserbeam are counted, and when a preset value is reached, two signalsare generated: one delayed trigger pulse with constant length and one delayed‘shutter pulse’ (referred to as the ‘shutter window’ below) which opens a light shutterand allows one light pulse to enter the experimental region and excite the sample.The delays of the trigger pulse and the shutter window and the width of the shutterwindow can all be set independently to any value from 0 up to 50 ms with 0.05 mssteps. A separate microcontroller measures the width of the shutter window with anaccuracy of 1micro seconds. The pulse delays and the width of the shutter window are setwith thumbwheel potentiometers connected as voltage dividers. A microcontrollerreads the set values with a four-channel, 12-bit AD converter. This techniquesaves a lot of hardware wiring as well as software writing when compared to thealternative of using separate, BCD-coded thumbwheels for each timesetting.In total, the instrument consists of two independent RISC-controllers: onePIC16C55 for counting chopper pulses and generating pulses and delays, and onePIC16C74 for measuring (and displaying) the width of the shutter window. Thewidth of the shutter window is measured with 1micro second resolution by taking fulladvantage of two different peripherial I/O devices in the PIC16C74: the 16-bit ‘inputcapture’ module and the external interrupt facility.
25.	Bengtsson, Lars, 1963 (författare) Implementation of Control algorithms in Small Embedded Systems 2020 Ingår i: Engineering. - : Scientific Research Publishing, Inc.. - 1947-3931 .- 1947-394X. ; 12:9, s. 623-639 Tidskriftsartikel (refereegranskat)abstract This work describes how a control algorithm can be implemented in a small (8-bit) microcontroller for the main purpose of merging embedded systems and control theory in electrical engineering undergraduate classes. Two different methods for discretizing the control expression are compared: Euler transformation and bilinear transformation. The sampling rate’s impact on the algorithm is discussed and theoretical results are verified by an application to a temperature control system in a heating plant. Four control algorithms are compared: PID and PI algorithms discretized with Euler and bilinear transformation, respectively. It is shown that for the heating plant used in this work, a bilinear PI algorithm implemented in a small 8-bit microcontroller outperforms a commercial controller from Panasonic. It is also demonstrated that all the derived algorithms can be implemented using integer calculations only, obviating the need for expensive and time-consuming floating-point calculations. This work bridges the gap between control theory equations and the implementation of control systems in small embedded systems with no inherent floating-point processing power.
26.	Bengtsson, Lars, 1963 (författare) Implementation of high-resolution time-to-digital converter in 8-bit microcontrollers 2012 Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 83:article no. 045107 Tidskriftsartikel (refereegranskat)abstract This paper will demonstrate how a time-to-digital converter (TDC) with sub-nanosecond resolution can be implemented into an 8-bit microcontroller using so called “direct” methods. This means that a TDC is created using only five bidirectional digital input–output-pins of a microcontroller and a few passive components (two resistors, a capacitor, and a diode). We will demonstrate how a TDC for the range 1–10 μs is implemented with 0.17 ns resolution. This work will also show how to linearize the output by combining look-up tables and interpolation.
27.	Bengtsson, Lars, 1963 (författare) Implementation of Vernier TDCs in 8-bit Microcontrollers 2014 Ingår i: Instrumentation and Measurement Technology Conference (I2MTC) Proceedings, 2014 IEEE International. - 9781467363860 ; , s. 1-4 Konferensbidrag (refereegranskat)abstract This paper discusses the aspects of implementing a TDC with Vernier resolution in a microcontroller system. Results will show that the proposed solution have a potential time resolution corresponding exactly to the theoretically expected resolution (equal to the time difference in the Vernier clocks’ period), but also that there is an inherent sample-to-sample uncertainty due to the fact that microcontrollers cannot compare two (running) timer registers in hardware. The moment of coincidence of the Vernier clocks must be detected in software and that will generate an uncertainty in the coincidence detection that depends on the microcontroller architecture. In the design example proposed, a time resolution of 2 ns is achieved using a PIC microcontroller clocked with a 20 MHz. However, the proposed method is general and resolution is limited only to the frequency matching of the two Vernier clocks.
28.	Bengtsson, Lars, 1963 (författare) Interpolation of Microcontroller ADC by self-induced dithering 2013 Ingår i: International Journal on Smart Sensing and Intelligent Systems. - 1178-5608. ; 6:4, s. 1366-1382 Tidskriftsartikel (refereegranskat)abstract The resolution of ADCs (Analog- to -Digital Converters) can be improved by dithering, i.e. by intentionally injecting white noise into the analog signal. This work describes the theory behind dithering, how to optimize the magnitude of the noise and also a design that illustrates how dithering can be implemented to increase the resolution of a microcontroller’s ADC. In order to demonstrate the potential of the design, the resolution of the 10-bit ADC of a PIC18F458 microcontroller is increased to 12 bits by dithering. This is possible by oversampling and decimation. The great advantage of the proposed design is that the noise is generated by the microcontroller itself, obviating the need of an external noise source
29.	Bengtsson, Lars, 1963 (författare) LabView från början : Version 6i 2001 Bok (övrigt vetenskapligt/konstnärligt)abstract LabVIEW är ett programmeringsspråk med grafiskt gränssnitt där inte bara in/utmatning av variabler sker i grafisk miljö, utan även själva programmeringen. Boken behandlar LabVIEW från grunden. Trots att inga förkunskaper behövs kommer vi fram till avancerad programskrivning för t ex mätdatainsamling, signal- och databehandling samt programstyrda hemsidor och e-mailfunktioner. Boken innehåller ca 140 övningar med lösningar.
30.	Bengtsson, Lars, 1963 (författare) LabView från början : Version 7 2004 Bok (övrigt vetenskapligt/konstnärligt)abstract LabVIEW är ett programmeringsspråk med grafiskt gränssnitt där inte bara in/utmatning av variabler sker i grafisk miljö, utan även själva programmeringen. Som programmerare behöver man alltså inte lägga någon tid på rätt kommandosyntax, utan all kraft kan läggas på struktureringen av programmet. Boken behandlar LabVIEW från grunden. Trots att inga förkunskaper behövs kommer vi fram till avancerad programskrivning för t ex mätdatainsamling, signal- och databehandling samt programstyrda hemsidor och e-mailfunktioner. Boken innehåller ca 140 övningar med lösningar.
31.	Bengtsson, Lars, 1963 (författare) LabView från början 2000 Bok (övrigt vetenskapligt/konstnärligt)abstract LabVIEW är ett programspråk med grafiskt gränssnitt där inte bara in/utmatning av variabler sker i grafisk miljö, utan även själva programmeringen. Boken behandlar LabVIEW från grunden. Trots att inga förkunskaper behövs kommer vi fram till avancerad programskrivning för t ex mätdatainsamling, signal- och databehandling samt programstyrda hemsidor och e-mail. Boken innehåller ca 140 övningar med lösningar.
32.	Bengtsson, Lars, 1963 (författare) Lookup Table Optimization for Sensor Linearization in Small Embedded Systems 2012 Ingår i: Journal of Sensor Technology. - : Scientific Research Publishing, Inc.. - 2161-122X .- 2161-1238. ; 2:4, s. 177-184 Tidskriftsartikel (refereegranskat)abstract This paper treats the problem of designing an optimal size for a lookup table used for sensor linearization. In small em- bedded systems the lookup table must be reduced to a minimum in order to reduce the memory footprint and intermedi- ate table values are estimated by linear interpolation. Since interpolation introduces an estimation uncertainty that in- creases with the sparseness of the lookup table there is a trade-off between lookup table size and estimation precision. This work will present a theory for finding the minimum allowed size of a lookup table that does not affect the overall precision, i.e. the overall precision is determined by the lookup table entries’ precision, not by the interpolation error.
33.	Bengtsson, Lars, 1963, et al. (författare) LowLevel C programming for Designers 2015 Bok (övrigt vetenskapligt/konstnärligt)abstract This book is concerned with C programming from an embedded systems engieer's point of view. That inlcudes writing device drivers for hardware with limited resources in terms of available instruction and data memory. A 32-bit soft CPU is implemented on an FPGA and theory is illustrated by detailed examples and cases.
34.	Bengtsson, Lars, 1963 (författare) Mikrocontrollers : Från assembler till RTOS 2011 Bok (övrigt vetenskapligt/konstnärligt)abstract En lärobok om inbyggda system som fokuserar på praktisk konstruktion av mikrodatorer baserade på så kallade "controllers". Behandlar t ex RFID, CAN-buss och implementering av real-tidsOS (RTOS) i små inbyggda system.
35.	Bengtsson, Lars, 1963 (författare) Mikrodatorteknik 1995 Bok (övrigt vetenskapligt/konstnärligt)abstract Första delen behandlar Microchips "Base-line"-kretsar och andra delen behandlar "Midrange"-kretsarna. De flesta funktioner belyses med konstruktionsexempel. Exempel och övningar är mycket hårdvarunära och boken behandlar konstruktion av mikrodatorer från grunden. Boken är avsedd för kurser i mikrodatorteknik på högskolan eller annan högre teknisk utbildning, men kan även användas som självstudiematerial eftersom de flesta exempel ges med detaljerade och verifierade lösningar av såväl hård- som mjukvaran. Tidigare erfarenhet av assemblerprogrammering är inte nödvändig men grundläggande kunskaper i digitalteknik förutsätts. Boken kan med fördel också läsas av rutinerade assemblerprogrammerare som vill veta hur prestanda hos de nya RISC-baserade PIC-controllerna står sig i konkurrensen med de mer etablerade enchipscontrollerna, t ex HC11 och 8751, som bygger på traditionell CISC-arkitektur.
36.	Bengtsson, Lars, 1963 (författare) Negative Ion Instrumentation for the Detection of the Electron Affinity of Astatine 2019 Ingår i: Sensors & Transducers Journal. - 1726-5479. ; 237:9-10, s. 122-128 Tidskriftsartikel (refereegranskat)abstract For the purpose of measuring the electron affinity of Astatine, a versatile tool for ion beam line up is proposed. Apertures in the ion optics are used to guide the beam and traditionally the current is measured on the apertures in order to detect the presence of an ion beam. By slitting the aperture into four separate pieces, the aperture current can also be used to determine the direction of the misalignment and the size of the ion beam diameter. A 4-channel pico ammeter with optical LED indication of the ion beam position is suggested in an analog/digital hybrid design. The design utilizes two charge/current-to-digital chips in a microcontroller design. This work is an important contribution to an ongoing project with the objective to determine the electron affinity of Astatine which is a potential α-radiation agent in radioimmunotherapy.
37.	Bengtsson, Lars, 1963 (författare) New design ideas for TDR-based liquid level detectors 2017 Ingår i: I2MTC 2017 - 2017 IEEE International Instrumentation and Measurement Technology Conference. 22-25 May 2017. Turin, Italy. Proceedings. - : IEEE. - 1091-5281. - 9781509035960 Konferensbidrag (refereegranskat)abstract This work suggests some new solutions to TDR-based liquid level detectors. A 3D-printed waveguide cylinder has been designed in order to increase the sensitivity of the level measurement. By wrapping the probing waveguide-pair around a cylinder, an inclination angle ϕ is introduced which increases the time-of-flight by a factor of 1/sinϕ and hence the level resolution is increased (by the same factor). This work also illustrates how nanosecond pulses (for TDR systems) can be generated by applying a technique usually found in FIMs (Field Ion Microscopes). A time resolution of 2 ns/mm (of liquid level) is reported and a generic nanosecond pulse generator isdemonstrated.
38.	Bengtsson, Lars, 1963 (författare) Novel 3D visualization of Laplace and Fourier transforms 2018 Ingår i: Trends in Technical & Scientific Research. ; 1:2, s. 001-003 Tidskriftsartikel (refereegranskat)abstract This paper will demonstrate how to illustrate poles and zeros of a filter’s transfer function as a 3D surface and how this facilitates an understanding of the relationship between the filter’s amplitude response and the poles’/zeros’ locations in s-space. The transfer function, in Laplace representation, is plotted as a function of the real and imaginary parts of the complex frequency s. This is exemplified for a Chebyshev-II low pass filter.
39.	Bengtsson, Lars, 1963 (författare) Programming Embedded Systems : 8-bit microcontrollers 2014 Bok (övrigt vetenskapligt/konstnärligt)abstract This book treats 8-bit microcontrollers; how to program them and how to design prototypes of embedded systems based on microcontrollers. Two microcontrollers from Microchip are used; a mid-range controller (PIC16F818) and an advanced controller (PIC18F4580). The first part treats assembler programming of mid-range controllers, but he main focus of this book is on C programming of advanced 8-bit controllers and the “embedded” aspects of C programming. All projects are designed as prototypes on a breadboard with inexpensive and widely available components. The software theory covers for example interrupt handling in C, multi-file projects and modularization of C programs (interface and implementation files, header file protection, generic functions etc). The hardware part covers all the integrated I/O units that a typical 8-bit controller has, like timers, ADCs, capture/compare/pwm modules, analog comparators and reference voltage, serial interfaces (RS-232 and SPI). We also introduce you to a lot of external hardware, like alpha numeric displays, graphical displays, keyboards, RS-232-to-USB conversion, RFID, DACs, sensors, stepper motors, servo motors, thumbwheels, ultra sound rangers, IR remote controllers, radio links and GPS chips. This book uses Microchip’s MPLAB® X IDE (Integrated Development Environment) and the XC8 C compiler. Both can be downloaded free of charge from Microchip’s home page.
40.	Bengtsson, Lars, 1963 (författare) Question-to-Learn Science in Higher Education: A Quantitative Study 2020 Ingår i: Higher Education Research. - : Science Publishing Group. - 2578-9341 .- 2578-935X. ; 5:3, s. 83-93 Tidskriftsartikel (refereegranskat)abstract This work reports the results of a case study where traditional activities in an engineering/science classroom, such as demonstrations and self-paced activities, were compared with ‘writing across the curriculum” (WAC) activities. One group did writing-to-learn assignments and one group did our seminal construct ‘question-to-learn’ where they designed exam problems for their peers. A model is presented which describes the parameters that influence the exam score outcome. Some of these variables were carefully controlled during the project (labs, textbook, lecturer) and some other parameters were measured (lecture attendance, time-on-task and previous knowledge) in order to minimize data corruption due to confounding variables. The main parameter of interest, the ‘predictor’ of the exam score was the extra-curricular activity. A pre-test and a post-test were also conducted in order to establish the students relative gain. We also tested the hypothesis of using the quality of the students’ WAC outputs as a predictor of academic achievements. Data is analyzed both with parametric and non-parametric methods and results show that there was no significant difference between the groups on exam scores and that the relationship between WAC quality and exam scores is not significant. The main reason for the non-significant results is concluded to be due to low participation rates and too low “dosage”.
41.	Bengtsson, Lars, 1963 (författare) RISC-baserad 50 MHz räknare med alfanumerisk display 1995 Ingår i: Allt om elektronik. ; 6, s. 35-37 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract Denna artikel presenterar en konstruktion som använder en RISC-kontroller (PIC16C54) som frekvensräknare. Frekvensen räknas på controllerns RTCC-ingång och signalfrekvensen, uttryckt i kHz visas på en alfanumerisk display.
42.	Bengtsson, Lars, 1963 (författare) Signalbehandling 2003 Ingår i: Tabeller och Formler. - Stockholm : Liber AB. - 9147050926 ; , s. 355-360 Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract Denna formel- och tabellsamling innehåller grundläggande definitioner, tabeller och formler inom det naturvetenskapliga och tekniska området. Boken är lämplig för högskoleingenjörsutbildning och grundläggande utbildningar för civilingenjörer. Författarnas inriktning har varit att ge boken en sådan bredd att den också kan användas som referenslitteratur på gymnasiet.
43.	Bengtsson, Lars, 1963 (författare) Signalbehandling 1996 Bok (övrigt vetenskapligt/konstnärligt)abstract I den här boken behandlas den del av signalbehandlingen som handlar om analoga och digital filter. Bokens innehåll är koncentrerat av analoga och digital filter. Filtersyntes disuteras endast undantagsvis. Den matematiska nivån ligger på högskolenivå och framför allt Laplace-, Fourier- och z-transformerna är mycket centrala begrepp i den teoretiska behandlingen av analoga och digitala filter.
44.	Bengtsson, Lars, 1963 (författare) Single-Chip Implementation of Level-Crossing ADC for ECG sampling 2017 Ingår i: Journal of Electrical & Electronic Systems. - : OMICS Publishing Group. - 2332-0796. ; 6:1 Tidskriftsartikel (refereegranskat)abstract This work demonstrates for the first time the implementation of a level-crossing analog-to-digital converter (LC-ADC) in a single, commercially available IC (that costs less than $2). The implementation utilizes adaptive threshold levels in order to prevent overload distortions for fast-changing signals. The entire design is based on a 20-pin PIC16F1769 microcontroller from Microchip and no external components are required. In fact, the only external circuitry required is a single jumper wire. This is due to the fact that the new generation of microcontrollers have integrated core-independent hardware, analog as well as digital. This design takes full advantage of the core-independent logic and analog blocks in a PIC16F17xx circuit to implement the LC-ADC technique that so far has required multiple-circuit designs or ASIC implementation. The design is demonstrated on a standard electrocardiogram (ECG) signal.
45.	Bengtsson, Lars, 1963 (författare) Single-chip Implementation of LVDT Signal Conditioning 2018 Ingår i: American Journal of Sensor Technology. - 2373-3454 .- 2373-3462. ; 5:1, s. 7-16 Tidskriftsartikel (refereegranskat)abstract The aim of this work was to prove that the signal conditioning electronics for linear variable transformers (LVDTs) can be implemented in inexpensive, general-purpose 8-bit microcontrollers, making expensive dedicated signal conditioning chips redundant. A low-cost, high-resolution signal conditioning solution for LVDTs is presented. Apart from a few external passive components, the entire solution is implemented in a low-cost, analog-digital hybrid microcontroller. The excitation sinusoid is generated by filtering out the fundamental frequency of a (self-sustained) pwm-generated square wave and the secondary coils’ signals are demodulated with classic peak detector circuits implemented in the microcontroller using a combination of its embedded analog and digital building blocks. A resolution of 1 μm over a range of ±6.35 mm for a commercial LVDT is reported and an uncertainty of 6 μm in the absolute value is deduced. The entire solution is implemented as surface mounted components on a small printed circuit board and the LVDT core displacement is displayed on an LCD display. Due to the simplicity and low-cost components required, this signal conditioning proposal has the potential to have a significant impact on commercial LVDT signal conditioning chips in the future since it is significantly less expensive than the present state-of-the-art signal conditioning chips offered by the main commercial suppliers and other solutions previously suggested in scientific literature.
46.	Bengtsson, Lars, 1963 (författare) Take-Home Exams in Higher Education: A systematic Review 2019 Ingår i: Education Sciences. - : MDPI AG. - 2227-7102. ; 9:4 Forskningsöversikt (refereegranskat)abstract This work describes a systematic review of the research on take-home exams in tertiary education. It was found that there is some disagreement in the community about the virtues of take-home exams but also a lot of agreement. It is concluded that take-home exams may be the preferred choice of assessment method on the higher taxonomy levels because they promote higher-order thinking skills and allow time for reflection. They are also more consonant with constructive alignment theories and turn the assessment into a learning activity. Due to the obvious risk of unethical student behavior, take-home exams are not recommended on the lowest taxonomy level. It is concluded that there is still a lot of research missing concerning take-home exams in higher education and some of this research may be urgent due to the emergence of massive online open courses (MOOCs) and online universities where non-proctored exams prevail.
47.	Bengtsson, Lars, 1963 (författare) Teaching Transforms: a vector approach 2015 Ingår i: International journal of mathematical education in science and technology. - 0020-739X. ; 46:5, s. 752-765 Tidskriftsartikel (refereegranskat)abstract This article treats the problem of introducing transform theory (Fourier, Laplace, z) to undergraduate students and we suggest a vector approach which means that signals (functions of time) should be treated as vectors from the beginning and that transforms are introduced as a scalar product; the transform should be presented as a tool to analyse the signal exactly in the same way as the dot product is used to analyse an ‘arrow’ vector in a Cartesian space. Hence, the transform becomes a tool to find the signal's magnitude in the directions of the basis vectors.
48.	Bengtsson, Lars, 1963, et al. (författare) The use of autoionizing states for efficient detection of Sr in resonance ionization mass spectrometry 1991 Ingår i: Institute of Physics Conference Series. - 0951-3248. ; 114:9, s. 377-380 Tidskriftsartikel (refereegranskat)abstract An efficient excitation scheme for RIMS of Sr has been investigated. Two-colour excitation has been used for excitation of the atoms to an autoionization level with both transitions in the visible region. The first step excitation was at 460.733 nm (5s2 1S0 -> 5s5p 1P1) and the second step leading to ionization was at 405.32 nm which connects the first excited state with a 1D2 autoionizing state at 46380 cm-1. This type of RIMS excitation scheme ensures selectively in both steps as well as an efficient degree of ionization. The choice of the visible wavelength helps also to minimize the influence of spectral interference as well as wing excitations of matrix species.
49.	Bengtsson, Lars, 1963, et al. (författare) Transformer : Från jw till wavelets 2007 Bok (övrigt vetenskapligt/konstnärligt)abstract Den här boken beskriver idéerna och matematiken bakom de vanligaste transformerna, Laplace-, Fourier- och z-transformen, sett framför allt ur elektroingnejörens perspektiv. Boken knyter också ihop transformernan, dles med den vanliga jw-metoden, och dels med en introduktion till wavelet-transform. Boken har ett stort antal övningar med fullständiga lösningar och lämpar sig väl som kursbok i transformkuresr eller som bredvidläsningsbok i signalbehandlingsnära kurser.
50.	Bengtsson, Lars, 1963, et al. (författare) Transformer 2007 Bok (övrigt vetenskapligt/konstnärligt)abstract Den här boken beskriver idéerna och matematiken bakom de vanligaste transformerna, Laplace-, Fourier- och z-transformen, sett framför allt ur elektroingnejörens perspektiv. Boken knyter också ihop transformernan, dles med den vanliga jw-metoden, och dels med en introduktion till wavelet-transform. Boken har ett stort antal övningar med fullständiga lösningar och lämpar sig väl som kursbok i transformkuresr eller som bredvidläsningsbok i signalbehandlingsnära kurser.

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