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  • 1.
    Hozhabri, Melika
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Comparison of UWB Radar Back-Scattering by the Human Torso and a Phantom2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    An Ultra Wide Band(UWB) radar is used to measure the cross section of a human phantom indifferent polarizations of the receiver antenna. The choice of material and shape for the human phantom is discussed. The material used in the experiment(wet sand) dielectric properties measured by a retromodeling technique and then calculated by mixture formulas. The appropriate frequency choice for the application is discussed.

  • 2.
    Hozhabri, Melika
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Study of the Environment Effect by M-Sequence UWB Radar on Detection of a Walking Human2016Ingår i: 2016 IEEE Conference on Antenna Measurements & Applications (CAMA) CAMA 2016, 2016, artikel-id 7815740Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an experimental comparison study of human movement and presence detection in different environments using ultra-wide-band (UWB) M-Sequence radar. The benchmarking measurements are made in an anechoic chamber and repeated in an open office environment. The wave forms of the background noise and scattered amplitudes of a human body are measured and compared. The result is analyzed and discussed. A set of detection algorithms and filters which are developed to track the human movement and presence is presented and the tracking results in these two environments are compared to each other.

  • 3.
    Otterskog, Magnus
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    A multi-layered head phantom for microwave investigations of brain hemorrhages2016Ingår i: 2016 IEEE Conference on Antenna Measurements & Applications (CAMA) CAMA 2016, Syracuse, United States, 2016, artikel-id 7815764Konferensbidrag (Refereegranskat)
    Abstract [en]

    A head phantom for microwave investigations is developed. It consists of a skull bone with realistic dielectric properties of cancellous and cortical bone. The skull phantom is filled with liquids and semi-solids that dielectrically represent the white/gray matter and blood, respectively.

  • 4.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Antenna applicator concepts using diffraction phenomena for direct visualization of brain hemorrhages2016Ingår i: 2016 IEEE Conference on Antenna Measurements & Applications (CAMA) CAMA 2016, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Direct use of diffraction phenomena at an irregularity in a lossy object such as a head is described. The source is an external magnetic field directed into the skull, creating a circulating current inside the object by which surface waves are avoided. The receiving E-field probe is a 3D resonant structure being selectively sensitive to the desired deflected electric field component from the surface.

  • 5.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Antenna Applicators and Microwave Fields for Imaging of the Interior of Human Breasts and Heads2016Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Breast tumor detection with microwave applicators in open air2017Ingår i: 2017 IEEE Conference on Antenna Measurements & Applications (CAMA) CAMA 2017, 2017, s. 272-274Konferensbidrag (Refereegranskat)
    Abstract [en]

    A system for either direct use of diffraction phenomena or indirect use by computational methods for female breast tumor detection is described. The excitation device is a single external non-contacting, sectioned single turn loop, creating an axial magnetic field directed into the breast. A circulating current is created inside it and the diffracted field is directly sensed.

  • 7.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Breast tumour detection by two microwave antenna principles2017Ingår i: Proceedings of the 2017 19th International Conference on Electromagnetics in Advanced Applications, ICEAA 2017, Institute of Electrical and Electronics Engineers Inc. , 2017, s. 1258-1261Konferensbidrag (Refereegranskat)
    Abstract [en]

    A comparison between breast tumour detection with a traditional lossy coupling medium based system and a system without coupling medium is performed, by numerical modelling and experimentally. While a system with lossy coupling medium offers surface wave reduction and protection from surrounding sources and obstacles it also demands good permittivity matching of the coupling medium to the breast tissue under investigation, as well as a high performance measurement system with a dynamic range exceeding 100 dB. The system without coupling medium offers possible direct detection of inhomogeneities with transmission losses of about 50...60 dB. The proposed contacting antenna system however needs further development in order to reduce stray fields and adoption to realistic breast tissue properties.

  • 8.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Experiments and numerical modelling of contacting antenna applicators at a free space head model2015Ingår i: 2015 IEEE International Conference on Antenna Measurements & Applications (CAMA) CAMA 2015, 2015, artikel-id 7428125Konferensbidrag (Refereegranskat)
    Abstract [en]

    Microwave absorbing boluses or similar are impractical, particularly in stroke emergencies, since the creation of surface waves around the head dominating over the internal signal paths is then a problem. The performance of miniaturised ridged waveguide applicators in the frequency interval 1 to 3 GHz designed for the application of breast cancer detection are used in this study, slightly modified, on head models for investigation of disturbing surface waves.

  • 9.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    QUANTIFICATION OF INHOMOGENEITIES IN OBJECTS BY ELECTROMAGNETIC FIELDS2017Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    A system and method, as well as sub assemblies thereof, for detection of dielectric irregularities/inhomogeneities inside an object under study (OUS) be means of electromagnetic energy are disclosed. The system comprises a loop/cylinder emitter configured to be located close to the OUS with its axis of symmetry directed towards the OUS. A feeding line feeds the emitter with an alternating current at an operating frequency to cause a magnetic field therein, which in turn will induce a propagating electromagnetic field in the OUS. In order to reduce propagating fields outside of the OUS, the circumference of the emitter is smaller than the free-space wavelength corresponding to the operating frequency, and the feeding line has a characteristic impedance that is smaller than 20 Ohm.

  • 10.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Pichot, Christian
    Université Côte d'Azur, France.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Further Developments of Applicator Concepts for Detection of Body Part Inhomogeneities2019Ingår i: 2019 IEEE CAMA Conference on Antenna Measurement and Applications 2019 CAMA, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present significant improvements on in particular our transmitting applicator and its performance. This is a crucial component of our system for direct detection of internal inhomogeneities such as breast tumors and brain hemorrhages by a special transmitting applicator and specially polarized receiving applicators. The operating frequency is about 1 GHz. The transmitting applicator is unique by no need to contact the object under study (OUS) and does not generate any surface waves at it. The primary field has properties behaving as from a magnetic monopole. The overall system allows direct detection without a need for phase measurements, which provides the possibility of using a simple microwave generator and simple rectification and position registration of the received signals. The receiving 3D contacting applicator contains a high-permittivity ceramic and is resonant in order to provide the desired field polarization sensitivity. The desired system properties are achieved by optimized use of the orthogonality properties of the primary magnetic, induced electric, and diffracted electric fields.

  • 11.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A Zirconia Cylindrical TM010 Cavity for Permittivity Measurements at 1 GHz2018Ingår i: 2018 IEEE CAMA Conference on Antenna Measurement and Applications CAMA 2018, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The most accurate dielectric measurements are made by resonant cavity methods, the circular TM010 type being the simplest and most common. However, an airfilled such cavity at 1 GHz needs to be 250 mm in diameter. There is another problem as well: its limited applicability with very lossy samples, due to a too low Q value. This paper describes the development and properties of a metalized zirconia ceramic cavity for use at about 1 GHz. With its permittivity ε′ = 30 its diameter becomes 40 mm instead of 150 mm for the airfilled version. Additionally and importantly, the dynamic range of the loss factor ε″ is greatly expanded. The calibration procedure using numerical retromodelling is described and a measurement example of a ternary alcohol mixture is carried out. The accuracy is also estimated.

  • 12.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Overview of microwave based diagnostics for breast tumours and strokes2018Ingår i: World Congress on Medical Physics and Biomedical Engineering IUPESM 2018, 2018, nr 1Konferensbidrag (Refereegranskat)
  • 13.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Tomasic, Ivan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Risman, Per Olov
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Detection of Human Bodypart Abnormalities by Microwaves – A New Approach2019Ingår i: 42nd International Convention on Information and Communication Technology, Electronics and Microelectronics MIPRO 2019, 2019, s. 270-274Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present modified antenna-like devices - applicators - for direct detection of internal inhomogeneities such as breast tumours and brain haemorrhages, at a frequency about 1 GHz. This direct detection provides the possibility of using a simple microwave generator and simple rectification and position registration of the received signals. Direct readouts are thus possible, without any massive computing resources as with tomographic imaging. The transmitting applicator is non-contacting and in free air close to the object. It generates an essentially quasistatic axial magnetic field which induces a circular electric field in the tissue. The receiving 3D contacting applicator contains a high-permittivity ceramic and is resonant. Its mode field provides the desired polarisation sensitivity and filters out the main electric field. The overall system sensitivity for detection of internal inhomogeneities is accomplished by optimised use of the orthogonality of the primary magnetic, induced electric, and diffracted electric fields. When developments are completed, the system will replace or complement existing commercial technologies at a low cost.

  • 14.
    Risman, Per Olov
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    MICROWAVE ANTENNA APPLICATOR2015Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    A new and comparatively small type of open-ended microwave applicators has been disclosed. They are for example suitable for transmission into and reception from contacting objects such as protruding human bodyparts for inhomogeneity detection by tomographic methods. The applicators according to the invention are of the dielectric-filled open-ended ridged rectangular TE10 type, with an insert filling the ridge and having a higher permittivity than the surrounding space. The shape of the insert can be as a frustrum pyramid towards the opening. The overall design promotes narrow beamwidths and minimises nearfields and surface wave excitation.

  • 15.
    Risman, Per Olov
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Översikt av mikrovågsbaserad diagnostik för brösttumörer och stroke2017Ingår i: Medicinteknikdagarna 2017 MTD 2017, Västerås, Sweden, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Forskningsområdet mikrovågsavbildning inom medicinen introducerades redan på 1980-talet av Larsen och Jacobi [1]. Objektet var en hundnjure nedsänkt i en mikrovågsabsorberande vätska (bolus) för att undvika störningar och direkt koppling mellan de två roterande antennmatriserna. Man fann att intressant mikrovågskontrastverkan kunde uppnås i biologiska objekt. Fördelar jämfört med mammografi är ex.vis att strålningen är helt ofarlig och att man kan »se» närmare revbenen. Nackdelen är att detaljbilden blir sämre om objektet är stort. Ett relativt enkelt sådant system har utvecklats på MDH [2]. System av denna typ innefattar krav på omfattande matematiska beräkningar för att få fram en bild. Idag anses den ledande utvecklingen ske av Meaney [3] som nu även tar fram ett system på Chalmers i Göteborg. System för stroke- och hjärnblödningsdetektion är under utveckling hos EMTensor i Österrike [4,5] och Medfield diagnostics i Göteborg [6]. Problemen med direkt vågutbredning med s.k. ytvågor längs skallytan blir stora eftersom man inte kan sänka ned skallen i vätska. Absorberande s.k. bolusar och även viss metallisk avskärmning (»huva») används av EM Tensor. En forskningsgrupp under Abbosh [7] har i laboratoriemiljö helt utan störningar lyckats uppnå vissa resultat utan bolusanvändning. Typiska antenner är modifierade kommunikationsantenner och man använder ett spektrum av frekvenser. Återigen blir systemen beräkningsintensiva. På MDH utvecklas f.n. två olika system. Det första har tredimensionella antenner och speciella åtgärder för eliminering av ytvågorna [8] samt kräver matematiska beräkningar som alla de föregående. Det andra bygger på en annan princip: polariserad direktdetektion av den. s.k. diffraktionen från exv. hjärnblödningsområdet och användning av vad som inte är antenner i vanlig mening [9]. Endast mycket enkel bildbehandling krävs, inte heller statistisk träning krävs för framtagning av slutdata så som tillämpas i exv. oljeindustrin för bestämning av olja/vatten/gas med mikrovågsteknik. Sammanfattningsvis karaktäriseras området av ett flertal aktiviteter, varav några pågått i många år. Orsaker till tidsutdräkterna är dels givetvis de allmänna svårigheterna med mikrovågsavbildning, men en ytterligare orsak är att mikrovågsvetenskapen och tekniken i sig är tvärvetenskaplig. En konsekvens av detta är att man inte tillräckligt tidigt ägnat sig åt de speciella ytvågs- och diffraktionsfenomen som kan förbättra mätresultaten.

  • 16.
    Risman, Per Olov
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Arch-Trapped Propagation in Enclosed and Free Space Biological Objects2018Ingår i: 2018 IEEE CAMA Conference on Antenna Measurement and Applications CAMA 2018, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The tendency of arch-trapped microwave propagation at curved surfaces is a kind of diffraction which needs more attention in the development of measurement systems, from the oil industry to the investigations using antenna applicator systems for biological objects. We develop equations for propagation in very lossy substances in metal pipes. Similar such propagation occurs at the periphery of rounded objects in air, where also surface wave effects occur and can cause measurement problems. We show a modified contacting antenna applicator minimizing arch-trapped as well as surface waves.

  • 17.
    Risman, Per Olov
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik. ES (Embedded Systems).
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik. ES (Embedded Systems).
    Detection of Diffraction Effects by Brain Haemorrhages With a Special Microwave Transmission System2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Hitherto described microwave modalities for detection of internal inhomogeneities in human tissues such as breasts and heads are by image reconstruction, requiring time consuming computational resources. The method developed at MDH is instead based on the use of magnetic field transducer, creating an essentially circular electrical field. This is in turn diffracted by the dielectric inhomogeneity and that signal is received by an E-field sensor in an appropriate position.

  • 18.
    Risman, Per Olov
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Petrovic, Nikola
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Tomasic, Ivan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    New work on radiofrequency electric and electromagnetic leakage hazards for operators safety assessments2019Ingår i: Medicinteknikdagarna 2019 MTD 2019, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Various medical and industrial equipment types with electric fields having frequencies in the range 13 to 40 MHz have a long history. The relative simplicity of the generators and applicators (i.e. the assembly which is adapted for the treatment) have led to equipment manufacturing by many small companies having insufficient knowledge about human exposure hazards. The international regulations on maximum allowed exposure are not well-developed and mainly concern limits of the measured electric field, so-called reference levels, which are set to low values considered to be safe under all possible conditions. – Quite some scientific work on the field characteristics has been carried out since the 1970’s, the goal in many cases having been to motivate further research grants rather than assisting industry in improving safety by proposing more detailed regulations. In particular, researchers have used the electric field strengths as measured, without consideration of the field curvature and decay rate from the equipment, and by also using a too simplistic approach to the “power flux density” of the field emission. – As a consequence of the above, it is estimated that over 90 % of today’s operational equipment does not fulfill these simple regulations. In spite of that, very few incidents or accidents are reported. – New ongoing work by the International Electrotechnical Commission (IEC; committee 27) is now explaining this. The work is based on advanced numerical modelling of typical kinds of equipment and humans in different postures of arms and hands. Some results will be demonstrated and indicate that from five to more than twenty times stronger fields can be accepted under conditions of limited direct access to the energised equipment parts such as electrodes and rails, and proper design of the system grounding.

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