Sverre Holm

Mest siterte publikasjoner

• J.-F. Synnevåg, A. Austeng, and S. Holm, "Adaptive beamforming applied to medical ultrasound imaging," IEEE Trans. Ultrason., Ferroelect., Freq. Contr. (Special issue on high resolution ultrasonic imaging), vol. 54(8), Aug. 2007, pp. 1606-1613.
• W. Chen and S. Holm, "Fractional Laplacian time-space models for linear and nonlinear lossy media exhibiting arbitrary frequency dependency," J. Acoust. Soc. Amer., pp. 1424-1430, Apr. 2004.
• J.-F. Synnevåg, A. Austeng, and S. Holm, ”Benefits of Minimum-Variance Beamforming in Medical Ultrasound Imaging”, IEEE Trans. Ultrason., Ferroelect., Freq. Contr., Sept. 2009.
• A. Austeng and S. Holm, "Sparse 2D Arrays for 3D Phased Array Imaging - Design Methods," IEEE Trans. Ultrasonics, Ferroelectrics and Frequency Control, Aug. 2002, pp. 1073-1086.
• W. Chen and S. Holm, "Modified Szabo’s wave equation models for lossy media obeying frequency power law," J. Acoust. Soc. Amer., pp. 2570-2574, Nov. 2003.

• Aparicio Sosa, Joaquin; Alvarez, Fernando J.; Hernandez, Alvaro & Holm, Sverre (2022). A Survey on Acoustic Positioning Systems for Location-Based Services. IEEE Transactions on Instrumentation and Measurement. ISSN 0018-9456. doi: 10.1109/TIM.2022.3210943. Vis sammendrag

  Positioning systems have become increasingly popular in the last decade for location-based services, such as navigation, and asset tracking and management. As opposed to outdoor positioning, where the global navigation satellite system became the standard technology, there is no consensus yet for indoor environments despite the availability of different technologies, such as radio frequency, magnetic field, visual light communications, or acoustics. Within these options, acoustics emerged as a promising alternative to obtain high-accuracy low-cost systems. Nevertheless, acoustic signals have to face very demanding propagation conditions, particularly in terms of multipath and Doppler effect. Therefore, even if many acoustic positioning systems have been proposed in the last decades, it remains an active and challenging topic. This article surveys the developed prototypes and commercial systems that have been presented since they first appeared around the 1980s to 2022. We classify these systems into different groups depending on the observable that they use to calculate the user position, such as the time-of-flight, the received signal strength, or the acoustic spectrum. Furthermore, we summarize the main properties of these systems in terms of accuracy, coverage area, and update rate, among others. Finally, we evaluate the limitations of these groups based on the link budget approach, which gives an overview of the system’s coverage from parameters such as source and noise level, detection threshold, attenuation, and processing gain.

• Chandrasekaran, Sri Nivas; Näsholm, Sven Peter & Holm, Sverre (2022). Wave equations for porous media described by the Biot model. Journal of the Acoustical Society of America. ISSN 0001-4966. 151(4), s. 2576–2586. doi: 10.1121/10.0010164. Fulltekst i vitenarkiv
• Svensson, Siri Fløgstad; Fuster i Garcia, Elies; Latysheva, Anna; Fraser-Green, Jorunn; Nordhøy, Wibeke & Darwish, Omar Isam [Vis alle 11 forfattere av denne artikkelen] (2021). Decreased tissue stiffness in glioblastoma by MR elastography is associated with increased cerebral blood flow. European Journal of Radiology. ISSN 0720-048X. 147. doi: 10.1016/j.ejrad.2021.110136. Fulltekst i vitenarkiv
• Aparicio, Joaquin & Holm, Sverre (2021). Obtaining range measurements from ambient noise cross-correlations for the self-calibration of nodes. CEUR Workshop Proceedings. ISSN 1613-0073. 3097. Fulltekst i vitenarkiv
• Lino, Paolo; Maione, Guido; Garrappa, Roberto & Holm, Sverre (2021). An approach to optimal integer and fractional-order modeling of electro-injectors in compression-ignition engines. Control Engineering Practice. ISSN 0967-0661. 115(104890). doi: 10.1016/j.conengprac.2021.104890.
• Svensson, Siri Fløgstad; De Arcos, José; Darwish, Omar Isam; Fraser-Green, Jorunn; Storås, Tryggve & Holm, Sverre [Vis alle 9 forfattere av denne artikkelen] (2021). Robustness of MR Elastography in the Healthy Brain: Repeatability, Reliability, and Effect of Different Reconstruction Methods. Journal of Magnetic Resonance Imaging. ISSN 1053-1807. 53(5), s. 1510–1521. doi: 10.1002/jmri.27475. Fulltekst i vitenarkiv
• Holm, Sverre; Holm, Thomas & Martinsen, Ørjan Grøttem (2021). Simple circuit equivalents for the constant phase element. PLOS ONE. ISSN 1932-6203. 16(3). doi: 10.1371/journal.pone.0248786. Fulltekst i vitenarkiv
• Fang, Jun; Näsholm, Sven Peter; Chen, Wen & Holm, Sverre (2020). The fractional constitutive models for nonlocal material based on scattering wave equations. Mechanics of Time-Dependent Materials. ISSN 1385-2000. doi: 10.1007/s11043-020-09482-w.
• Holm, Sverre (2020). Time domain characterization of the Cole-Cole dielectric model. Journal of Electrical Bioimpedance. ISSN 1891-5469. 11(1), s. 101–105. doi: 10.2478/JOEB-2020-0015. Fulltekst i vitenarkiv Vis sammendrag

  The Cole-Cole model for a dielectric is a generalization of the Debye relaxation model. The most familiar form is in the frequency domain and this manifests itself in a frequency dependent impedance. Dielectrics may also be characterized in the time domain by means of the current and charge responses to a voltage step, called response and relaxation functions respectively. For the Debye model they are both exponentials while in the Cole-Cole model they are expressed by a generalization of the exponential, the Mittag-Leffler function. Its asymptotes are just as interesting and correspond to the Curie-von Schweidler current response which is known from real-life capacitors and the Kohlrausch stretched exponential charge response.

• Yang, Xu; Cai, Wei; Liang, Yingjie & Holm, Sverre (2020). A novel representation of time-varying viscosity with power-law and comparative study. International Journal of Non-Linear Mechanics. ISSN 0020-7462. 119, s. 1–10. doi: 10.1016/j.ijnonlinmec.2019.103372.
• Esmonde, Harry & Holm, Sverre (2020). Fractional derivative modelling of adhesive cure. Applied Mathematical Modelling. ISSN 0307-904X. 77(2), s. 1041–1053. doi: 10.1016/j.apm.2019.08.021.
• Holm, Sverre (2019). Dispersion analysis for wave equations with fractional Laplacian loss operators. Fractional Calculus and Applied Analysis. ISSN 1311-0454. 22(6), s. 1596–1606. doi: 10.1515/fca-2019-0082.
• Parker, Kevin; Szabo, Thomas & Holm, Sverre (2019). Towards a consensus on rheological models for elastography in soft tissues. Physics in Medicine and Biology. ISSN 0031-9155. 64(21). doi: 10.1088/1361-6560/ab453d. Vis sammendrag

  A rising wave of technologies and instruments are enabling more labs and clinics to make a variety of measurements related to tissue viscoelastic properties. These instruments include elastography imaging scanners, rheological shear viscometers, and a variety of calibrated stress–strain analyzers. From these many sources of disparate data, a common step in analyzing results is to fit the measurements of tissue response to some viscoelastic model. In the best scenario, this places the measurements within a theoretical framework and enables meaningful comparisons of the parameters against other types of tissues. However, there is a large set of established rheological models, even within the class of linear, causal, viscoelastic solid models, so which of these should be chosen? Is it simply a matter of best fit to a minimum mean squared error of the model to several data points? We argue that the long history of biomechanics, including the concept of the extended relaxation spectrum, along with data collected from viscoelastic soft tissues over an extended range of times and frequencies, and the theoretical framework of multiple relaxation models which model the multi-scale nature of physical tissues, all lead to the conclusion that fractional derivative models represent the most succinct and meaningful models of soft tissue viscoelastic behavior. These arguments are presented with the goal of clarifying some distinctions between, and consequences of, some of the most commonly used models, and with the longer term goal of reaching a consensus among different sub-fields in acoustics, biomechanics, and elastography that have common interests in comparing tissue measurements.

• Chandrasekaran, Sri Nivas & Holm, Sverre (2019). A multiple relaxation interpretation of the extended Biot model. Journal of the Acoustical Society of America. ISSN 0001-4966. 146(1), s. 330–339. doi: 10.1121/1.5116139.
• Kvam, Johannes; Holm, Sverre & Angelsen, Bjørn Atle Johan (2019). Exploiting Ballou's rule for better tissue classification. Journal of the Acoustical Society of America. ISSN 0001-4966. 145(4), s. 2103–2112. doi: 10.1121/1.5096533.
• Patz, Samuel; Fovargue, Daniel; Schregel, Katharina; Nazari, Navid; Palotai, Miklos & Barbone, Paul E. [Vis alle 12 forfattere av denne artikkelen] (2019). Imaging localized neuronal activity at fast time scales through biomechanics. Science Advances. ISSN 2375-2548. 5(4). doi: 10.1126/sciadv.aav3816.

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• Holm, Sverre (2021). Den innbilte konflikten. Om naturvitenskap og Gud. Veritas forlag. ISBN 978-82-8385-036-9. 359 s.
• Holm, Sverre (2019). Waves with Power-Law Attenuation. Springer Nature. ISBN 978-3-030-14927-7. 312 s. Vis sammendrag

  This book integrates concepts from physical acoustics with those from linear viscoelasticity and fractional linear viscoelasticity. Compressional waves and shear waves in applications such as medical ultrasound, elastography, and sediment acoustics often follow power law attenuation and dispersion laws that cannot be described with classical viscous and relaxation models. This is accompanied by temporal power laws rather than the temporal exponential responses of classical models. The book starts by reformulating the classical models of acoustics in terms of standard models from linear elasticity. Then, non-classical loss models that follow power laws and which are expressed via convolution models and fractional derivatives are covered in depth. In addition, parallels are drawn to electromagnetic waves in complex dielectric media. The book also contains historical vignettes and important side notes about the validity of central questions. While addressed primarily to physicists and engineers working in the field of acoustics, this expert monograph will also be of interest to mathematicians, mathematical physicists, and geophysicists.

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• Holm, Sverre (2022). Gud og vitenskap – Kan jeg tro på begge deler?
• Holm, Sverre (2022). En innbilt konflikt mellom naturvitenskap og gudstro?
• Holm, Sverre (2022). Gode grunner til at konflikten mellom vitenskap og Gud er innbilt.
• Aparicio, Joaquin; Thio, Vincent Martello Kwie Hoe & Holm, Sverre (2022). Range evaluation between indoor microphones obtained from acoustic ambient noise cross-correlations.
• Holm, Sverre (2021). Naturvitenskap og Gud er ikke konkurrenter. Dagen : kristelig dagblad. ISSN 0805-4738.
• Holm, Sverre (2021). Ber kirken ta oppgjør med kirkehets i skolen. [Avis]. Dagen.
• Holm, Sverre (2021). – Trist at folk tror det er en konflikt mellom tro og vitenskap. [Avis]. Vårt Land. Vis sammendrag

  TROSFORSVAR: Flere kristne filosofer og forskere reagerer på biolog Kristian Gundersens anmeldelse av Sverre Holms trosforsvar: – Vitenskapen kan ikke besvare spørsmål om moral eller menneskeverd.

• Kvellestad, Anders; Normann, Ben David & Holm, Sverre (2021). Om Gud, fysikk og de dype spørsmålene. Avisa Vårt land. Vis sammendrag

  EKSISTENS: Vi er både er fysikere og troende – og vi har like lite tro på julenissen, spøkelser eller «en usynlig magisk mann» som det Wetteland har.

• Holm, Sverre (2021). En anmeldelse av en innbilt bok. Avisa Vårt land. Vis sammendrag

  LITTERATUR: Jeg skulle ønske at Vårt Land hadde anmeldt min bok «Den innbilte konflikten», heller enn å anmelde en innbilt bok om Guds eksistens og Bibelen.

• Holm, Sverre (2021). Gudstru og vitskap (Kompass). [Radio]. NRK P1.
• Holm, Sverre (2021). The Roots of Mathematics and Natural Laws: Materialism vs Theism.
• Holm, Sverre (2021). Hensikt eller tilfeldighet?
• Holm, Sverre (2021). Gode grunner til at naturvitenskap og Gud ikke er i konflikt.
• Holm, Sverre (2021). Abels forgård: Gud og gullkabler. [Radio]. NRK P2. Vis sammendrag

  Dagens makker er professor i signalbehandling, og hisset for noen år siden på seg mektige krefter i NRK da han skrev om lydkvaliteten på DAB-radio. Og i høst klarte han kunststykket å hisse på seg både ateister og konservative kristne med sin bok om forholdet mellom Naturvitenskap og Gud. Ukas makker: fysikkprofessor Sverre Holm

• Holm, Sverre (2021). Fractionality in time-varying systems.
• Holm, Sverre (2021). Fractional wave equations appear naturally in complex media.
• Aparicio, Joaquin & Holm, Sverre (2021). Evaluation of acoustic ambient noise cross-correlations in indoor environments.
• Holm, Sverre (2021). Non-integer derivatives in selected areas of physics.
• Holm, Sverre (2021). Non-integer derivatives in acoustics and other areas of physics.
• Holm, Sverre (2021). Lysloven på Kanariøyene.
• Holm, Sverre (2021). Long delayed radio echoes – the illusive secret of the ionosphere. Vis sammendrag

  The first radio echoes with long delays were reported in 1927 by Jørgen Hals in Oslo, Norway on 9.54 MHz signals from the Netherlands. His first report exists at the National Library in Oslo and was later reported in Nature [Størmer, 1928]. Controlled experiments where delays ranged from 3 to 30 seconds confirmed the phenomenon and convinced most skeptics that the phenomenon was real [van der Pol, 1928]. About 15 different hypotheses have been presented over time for their cause [Shlionskiy 1985]. The five most likely ones will be presented here. They involve phenomena with long-distance travel such as around the world many times or reflection from plasma clouds. Another scenario is where the speed of propagation is substantially slower than normal as if there is mode conversion to mechanical waves in the ionosphere with or without nonlinearity [Vidmar, Crawford 1985]. The only one of the five which is understood well is when a signal is ducted in the magnetosphere and reflected from the opposite hemisphere. It may occur for frequencies up to 4 MHz and will give delays of up to 0.5 seconds. The further north, the longer the delay. Therefore, such medium delay echoes may sometimes be confused with round-the-world echoes of 138 ms, which however seldom occur at such low frequencies. There are examples of such echoes from Tasmania and St. Petersburg in the scientific literature. Amateur operator reports from New York, Georgia, California, Newfoundland, Denmark, and the UK [Martinez, 2007] from the last decades will be presented and analyzed and audio from some of them will be demonstrated. The delay is predictable from geomagnetic latitude using a simplified dipole model for the geomagnetic field line [Holm 2009]. The effect occurs during the dark hours and is most likely during winter months of years of low solar activity. A good report of such a phenomenon should involve a digital recording of audio using CW and not SSB signals. Delay measurement with amateur radio equipment is a challenge and needs to compensate for the usual delay between the onsets of the transmitter and sidetone signals.

• Holm, Sverre (2020). Justification for power laws and fractional models.
• Holm, Sverre (2020). Power-laws and fractional calculus.
• Holm, Sverre (2020). Waves with Power-Law Attenuation.
• Holm, Sverre (2020). Waves with Power-Law Attenuation. Vis sammendrag

  My book with title «Waves with Power-Law Attenuation» came out in June 2019 (https://www.springer.com/gp/book/9783030149260). It integrates concepts from physical acoustics with those from linear viscoelasticity and fractional linear viscoelasticity. Compressional waves and shear waves in applications such as medical ultrasound, elastography, and sediment acoustics often follow power law attenuation and dispersion laws in frequency that cannot be described with classical viscous and relaxation models. This is accompanied by temporal power laws rather than the temporal exponential responses of classical models. The book starts by reformulating the classical models of acoustics in terms of standard models from linear elasticity. Then, non-classical loss models that follow power laws and which are expressed via convolution models and fractional derivatives are covered in depth. This couples fractional derivatives and power laws and it is possible to give their multiple relaxation process interpretation. Other causes of power law attenuation and dispersion such as interaction with hierarchical models of polymer chains and non-Newtonian viscosity are also studied. Similar fractional and multiple relaxation models are as well inherent in the grain shearing and extended Biot descriptions of sediment acoustics. Finally power-law attenuation due to multiple scattering in fractal structures is covered.

• Holm, Sverre (2020). Abel’s 1823 Paper on Fractional Derivatives and Waves with Power-Law Attenuation. Vis sammendrag

  In 1823 Niels Henrik Abel published a paper with title "Oplösning af et par opgaver ved hjelp af bestemte integraler," (Solution of a couple of problems by means of definite integrals), Magazin for Naturviden-skaberne, Aargang I, Bind 2, Christiania, which did not appear in French translation until 1881. Here he presented a complete framework for fractional-order calculus with appropriate notation for non-integer-order integration and differentiation. This seems to have been unknown until discussed in Podlubny, Magin, Trymorush, "Niels Henrik Abel and the birth of fractional calculus," Fractional Calculus and Applied Analysis, pp. 1068-1075, 2017. I will give an introduction to non-integer order calculus and Abel's derivation of it. This will be done by going through his 1823 paper showing how he assumes a generalization of both Cauchy's formula for repeated integration and the fundamental theorem of calculus. In addition I will show how fractional calculus can be used to derive fractional-order partial differential wave equations. They have solutions with power-law attenuation which matches measurements in the complex media of medical ultrasound and elastography as well as in sediment acoustics and seismics.

• Chandrasekaran, Sri Nivas & Holm, Sverre (2019). Erratum: A multiple relaxation interpretation of the extended Biot model (Journal of the Acoustical Society of America (2019) 146 (330-339) DOI: 10.1121/1.5116139). Journal of the Acoustical Society of America. ISSN 0001-4966. 146(6), s. 4322–4323. doi: 10.1121/1.5139414.
• Aparicio, Joaquin; Alvarez, Fernando; Hernandez, Alvaro & Holm, Sverre (2019). A review of techniques for ultrasonic indoor localization systems.
• Holm, Sverre (2019). Troende naturforskere gjennom 400 år ved seks av dem.
• Holm, Sverre (2019). Troende naturforskere gjennom 400 år ved seks av dem.
• Holm, Sverre (2019). Er naturvitenskap Teorien om Alt?
• Holm, Sverre (2019). Troende naturforskere gjennom 400 år ved åtte av dem.

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