| 1. |
- Choudhary, Vipin
(författare)
-
Nondestructive testing and antenna measurements using UWB radar in industrial applications
- 2021
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many industries are rapidly substituting the manual test operations and move towards automated operations using modern technologies.Modern technologies such as digital cameras, sonic sensors, infrared sensors, and radar and lidar systems are used for non-destructive testingoperations. Among all the different sensors, radar systems have theability to penetrate built structures (dielectric materials), which makes them flexible and suitable for a wide range of industrial and military applications in non-destructive sensing. Such examples are the detection of damages in goods manufacturing, monitoring the health of manystructures, object detection through the wall for security purposes, etc.In particular, ultra-wide-band (UWB) radar systems are beneficial inproviding high measurement accuracy and simultaneously reduced sensitivityto passive interference (such as rain, smoke, mist etc.), immunity to external radiation and noise.The objectives of this thesis are: I) to investigate electrically small concealed structures using synthetic aperture radar (SAR), II) to determinethe complex refractive index of objects using an UWB radar system,and III) to answer to the question how we can reduce the mutual coupling (cross talk) in an UWB radar system with collocated transmitand receive antennae. In objective I, the aim is non-destructive testing of built structures, such as in concrete slab manufacturing or for use in the renovation process. In addition electrically small periodic meshes,and their orientation, could not be distinguished in conventional SAR images. The proposed polarimetric analysis method demonstrates the usefulness of the singular value decomposition (SVD) using back projection algorithm (BPA) in extracting information about shape and for classifying an electrically small object. Further in this thesis for objective II, a new method for determining the complex refractive index (or equivalently the complex relative permittivity) of objects with planar interfaces is presented. The proposed method is relatively insensitive to hardware-impairments such as frequency-dependence of antennas and analog front end. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. Hence, the method is designed for industrial in-line measurements onobjects on conveyor belts. Furthermore, in the following parts of this thesis −objective III− we investigate and show how a microwave metamaterial based absorber can be used to improve the performance of aradar system for short range applications, when positioned between the transmit and receive antennas. As results, the error in estimated target distance is reduced and clutter reduction is improved.
|
|
| 2. |
- Hansson, Edvin, 1987-
(författare)
-
Internal Dosimetry in Nuclear Fuel Fabrication : Occupational Exposure to Uranium Aerosols
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The production of nuclear fuel can be associated with occupational exposure to ionizing radiation from radioactive decay of uranium. Such exposure must be sufficiently low and radiation doses adequately determined. Radiation doses from internal exposure, i.e., following intake (usually inhalation), cannot be estimated using dosimeters, but must be calculated based on indirect measurements in combination with biokinetic models.Such biokinetic models have been developed and refined for decades. Good knowledge of the material characteristics is crucial. However, the physicochemical properties of chemical compounds can vary between different production facilities. Aerosol size distributions and dissolution characteristics in lung fluid are of particular importance. The latter is important since dissolved material is absorbed to blood, whereupon a large fraction reaches the urine after filtering by the kidneys. This enables urine sampling as a method to monitor occupational exposure.The aim of this thesis was to investigate the physicochemical properties of uranium aerosols and their implication on internal dose assessments at a nuclear fuel fabrication plant in Sweden. Uranium aerosols were sampled and size fractionated using personal cascade impactors carried by workers at the factory’s different main workshops. Aerosols were studied using scanning electron microscopy in Paper I. In Paper II the activity size distributions were determined and in Paper III dissolution rates in simulated lung fluid were investigated. Paper IV is an internal dose assessment based on records of urine sample analyses from about 10 years of routine occupational exposure monitoring of uranium pelletizing workers at the site.For a median worker, the urinary daily excretion rate of uranium increased due to chronic exposure for about 1000 days, after which the excretion rate stabilized. This suggests that inhaled material dissolves in the respiratory tract rapidly enough to prevent a net buildup in the lung after several years of exposure. This could be modelled using the default recommendations for uranium oxide materials provided by the International Commission on Radiological Protection. However, the best model fit to measurement data was obtained using a different set of parameters, that showed some discrepancies with results from Papers II-III. For individual cases, excretion rates could vary between sampling occasions to a greater extent than predicted using the default recommendations, which could indicate a more rapid body clearance than expected. Whether this is an effect of experimental methods or simplifications in the biokinetic models should be further investigated in future work.
|
|
| 3. |
- Javadi, Mohammad Saleh, 1986-
(författare)
-
Computer Vision Algorithms for Intelligent Transportation Systems Applications
- 2018
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, Intelligent Transportation Systems (ITS) have emerged asan efficient way of enhancing traffic flow, safety and management. Thesegoals are realized by combining various technologies and analyzing the acquireddata from vehicles and roadways. Among all ITS technologies, computervision solutions have the advantages of high flexibility, easy maintenanceand high price-performance ratio that make them very popular fortransportation surveillance systems. However, computer vision solutionsare demanding and challenging due to computational complexity, reliability,efficiency and accuracy among other aspects. In this thesis, three transportation surveillance systems based on computervision are presented. These systems are able to interpret the imagedata and extract the information about the presence, speed and class ofvehicles, respectively. The image data in these proposed systems are acquiredusing Unmanned Aerial Vehicle (UAV) as a non-stationary sourceand roadside camera as a stationary source. The goal of these works is toenhance the general performance of accuracy and robustness of the systemswith variant illumination and traffic conditions. This is a compilation thesis in systems engineering consisting of threeparts. The red thread through each part is a transportation surveillancesystem. The first part presents a change detection system using aerial imagesof a cargo port. The extracted information shows how the space isutilized at various times aiming for further management and developmentof the port. The proposed solution can be used at different viewpoints andillumination levels e.g. at sunset. The method is able to transform the imagestaken from different viewpoints and match them together. Thereafter,it detects discrepancies between the images using a proposed adaptive localthreshold. In the second part, a video-based vehicle's speed estimationsystem is presented. The measured speeds are essential information for lawenforcement and they also provide an estimation of traffic flow at certainpoints on the road. The system employs several intrusion lines to extractthe movement pattern of each vehicle (non-equidistant sampling) as an inputfeature to the proposed analytical model. In addition, other parameters such as camera sampling rate and distances between intrusion lines are alsotaken into account to address the uncertainty in the measurements and toobtain the probability density function of the vehicle's speed. In the thirdpart, a vehicle classification system is provided to categorize vehicles into\private car", \light trailer", \lorry or bus" and \heavy trailer". This informationcan be used by authorities for surveillance and development ofthe roads. The proposed system consists of multiple fuzzy c-means clusterings using input features of length, width and speed of each vehicle. Thesystem has been constructed by using prior knowledge of traffic regulationsregarding each class of vehicle in order to enhance the classification performance.
|
|
| 4. |
- Mohseni, Farzad, 1981-
(författare)
-
Power to gas : Bridging renewable electricity to the transport sector
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Globally, transport accounts for a significant part of the total energy utilization and is heavily dominated by fossil fuels. The main challenge is how the greenhouse gas emissions in road transport can be addressed. Moreover, the use of fossil fuels in road transport makes most countries or regions dependent on those with oil and/or gas assets. With that said, the question arises of what can be done to reduce the levels of greenhouse gas emissions and furthermore reduce dependency on oil? One angle is to study what source of energy is used.Biomass is considered to be an important energy contributor in future transport and has been a reliable energy source for a long time. However, it is commonly known that biomass alone cannot sustain the energy needs in the transport sector by far.This work presents an alternative where renewable electricity could play a significant role in road transport within a relatively short time period. Today the amount of electricity used in road transport is negligible but has a potential to contribute substantially. It is suggested that the electricity should be stored, or “packaged” in a chemical manner, as a way of conserving the electrical energy. One way of doing so is to chemically synthesize fuels. It has been investigated how a fossil free transport system could be designed, to reach high levels of self-sufficiency. According to the studies, renewable electricity could have the single most important role in such a system. Among the synthetic fuels, synthetic methane (also called synthetic biogas) is the main focus of the thesis. Hydrogen is obtained through water electrolysis, driven by electricity (preferable renewable), and reacted with carbon dioxide to produce synthetic methane. The concept of the mentioned process goes under the name Power to Gas. The electricity to fuel efficiency of such a process reaches about 50 %, but if utilizing excess heat produced during the electrolysis and the reaction, the total process efficiency can reach much higher levels.The economics of the process is as important as the technology itself in terms of large scale implementation. The price of electricity and biogas are the most important influences on the economic viability. The minimum “spread” between purchase and selling price can be determined to obtain a general perception of the economic feasibility. In this case biogas must be sold about 2.6 times higher than purchased electricity per kWh.
|
|
| 5. |
- Luttropp, Agneta, 1945-
(författare)
-
Närhet : Samspel och delaktighet i förskolan för barn med utvecklingsstörning
- 2011
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose was to study if children with intellectual disability interact or participate differently with preschool staff and peers compared to their non-disabled peers and how preschool teachers experience interaction and participation for children with intellectual disability and children with typical development. The results from study I show that there are more similarities than differences between the groups. There are no differences between the groups neither in engagement nor in what kind of material the children use or in what setting they play. The results indicated that children with intellectual disability interacted in the same contexts as their peers. Significant differences were found, indicating that the children with intellectual disabilities communicate less and especially less with peers. Children with intellectual disability are more often close to a teacher than children with typical development. Teacher’s communication indicates that teachers communicate and initiate more often to children with intellectual disabilities. Results from study II showed that the main difference between the target child and the control child expressed from the teachers was in the area communication. Participation differed in structured and unstructured situations even if it is not significant. The child with intellectual disability was less involved in his/her live situation in unstructured situations. The results from Individual Plans showed that goals and methods about communication were more common as a goal than interaction even if the teachers expressed that interaction is the child’s main problem.
|
|
| 6. |
- Alves, Dimas irion, et al.
(författare)
-
Change Detection Method for Wavelength-Resolution SAR Images Based on Bayes’ Theorem : An Iterative Approach
- 2023
-
Ingår i: IEEE Access. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 11, s. 84734-84743
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an iterative change detection (CD) method based on Bayes’ theorem for very high-frequency (VHF) ultra-wideband (UWB) SAR images considering commonly used clutter-plus-noise statistical models. The proposed detection technique uses the information of the detected changes to iteratively update the data and distribution information, obtaining more accurate clutter-plus-noise statistics resulting in false alarm reduction. The Bivariate Rayleigh and Bivariate Gaussian distributions are investigated as candidates to model the clutter-plus-noise, and the Anderson-Darling goodness-of-fit test is used to investigate three scenarios of interest. Different aspects related to the distributions are discussed, the observed mismatches are analyzed, and the impact of the distribution chosen for the proposed iterative change detection method is analyzed. Finally, the proposed iterative method performance is assessed in terms of the probability of detection and false alarm rate and compared with other competitive solutions. The experimental evaluation uses data from real measurements obtained using the CARABAS II SAR system. Results show that the proposed iterative CD algorithm performs better than the other methods. Author
|
|
| 7. |
- Carlsen Misic, Martina, 1986-, et al.
(författare)
-
Clonidine as analgesia during retinopathy of prematurity screening in preterm infants (cloROP) : protocol for a randomised controlled trial
- 2022
-
Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:9
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction Preterm infants are at risk of negative consequences from stress and pain at the same time as they often are in need of intensive care that includes painful interventions. One of the frequent painful procedures preterm infants undergo is eye examination screening to detect early signs of ROP (retinopathy of prematurity). These examinations are both stressful and painful, and despite a multitude of research studies, no conclusive pain-relieving treatment has been demonstrated. The main aim of this trial is to investigate the analgesic effect of clonidine during ROP eye examinations.Methods and analysis The planned study is a multicentre randomised controlled trial with a crossover design. Infants will be recruited from two different neonatal intensive care units (NICUs) in Sweden. Infants born before gestation week 30 (and therefore eligible for ROP screening) and cared for in either of the NICUs will be eligible for inclusion in the study. The primary outcome will be Premature Infant Pain Profile–Revised score within 30 s after starting the examination. Secondary outcomes will be changes in the galvanic skin response parameters (area small peaks, area huge peaks, peaks per second and average rise time) within 30 s after starting the eye examination, together with the number and evaluation of adverse events reported within 72 hours after the examination and the examining physician’s assessment of how easy the infant was to examine.Ethics and dissemination Approval from the Swedish Ethical Review Authority and the Swedish Medical Products Agency has been obtained for the study. Parents of eligible infants will be getting both verbal and written information about the study including that participation is voluntary. Data will be collected and treated in accordance with the European general data protection regulations. The results will be reported on group level and published in a scientific journal.
|
|
| 8. |
- Carlsen Misic, Martina, 1986-, et al.
(författare)
-
Clonidine as analgesia during retinopathy of prematurity screening in preterm infants -cloROP
- 2024
-
Konferensbidrag (refereegranskat)abstract
- BackgroundPreterm infants are vulnerable and sensitive to stimuli, during their stay in neonatal intensive care they undergo frequent stressful and painful procedures. One of these painful procedures is the screening for retinopathy of prematurity, ROP. In Sweden all preterm infants born before gestation week 30 undergo ROP-screening. The screening involves regular eye examinations to detect ROP at the early stages and these examinations are both stressful and painful. Several studies have investigated different ways of pain management during eye examinations with inconsequent results. No study has investigated Clonidine as pain management during ROP-screening. AimThe aim of this clinical trial is to investigate the analgesic effect of clonidine during ROP eyeexaminations.MethodThis study is a multicenter randomized controlled clinical trial with a crossover design. Infants born before gestation week 30 and therefore undergoing ROP-screening, will be eligible for inclusion in the study. Infants will be recruited from two Swedish NICUs (neonatal intensive care units). The NICUs use different examination techniques, where NICU A uses indirect ophthalmoscopy while NICU B uses RetCam. A total of 50 infants will be recruited (25 at each NICU). During the first eye examination the infant will be randomized to either clonidine 4mcg/kg or sterile water in the equivalent dose 60 minutes before the eye examination. The order of the treatment is blinded for everyone except the nurse preparing the study solution. During the second eye examination the infant will receive the study solution, (intervention or placebo) that he/she did not receive the first time. The primary outcome of the study is pain assessment with the Premature Infant Pain Profile – Revised. The infants´ face and monitor showing oxygen saturation and heart rate will be videorecorded to be able to assess the pain afterwards. The secondary outcome is Galvanic Skin Response where three probes are attached to the infant’s foot sole to register changes in the sweat gland activity in response to stimuli such as pain or stress. The ophthalmologist performing the eye examination will also rate how easy it was to examine the infant by marking an X on a 10cm VAS scale with “very easy to examine” on one end and “very difficult to examine” on the other end. Data collection is ongoing with 19 infants included at the moment.
|
|
| 9. |
- Edlund, Jens, Docent/Associate Professor, 1967-, et al.
(författare)
-
A Multimodal Digital Humanities Study of Terrorism in Swedish Politics: An Interdisciplinary Mixed Methods Project on the Configuration of Terrorism in Parliamentary Debates, Legislation, and Policy Networks 1968–2018
- 2022
-
Ingår i: Intelligent Systems and Applications. Proceedings of the 2021 Intelligent Systems Conference, September 2–3, 2021 / Arai K. (eds). - Cham : Springer. - 2367-3370 .- 2367-3389. - 9783030821951 ; , s. 435-449
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the design of one of Sweden’s largest digital humanities projects, SweTerror, that through an interdisciplinary multi-modal methodological approach develops an extensive speech-to-text digital HSS resource. SweTerror makes a major contribution to the study of terrorism in Sweden through a comprehensive mixed methods study of the political discourse on terrorism since the late 1960s. Drawing on artificial intelligence in the form of state-of-the-art language and speech technology, it systematically analyses all forms of relevant parliamentary utterances. It explores and curates an exhaustive but understudied multi-modal collection of primary sources of central relevance to Swedish democracy: the audio recordings of the Swedish Parliament’s debates. The project studies the framing of terrorism both as policy discourse and enacted politics, examining semantic and emotive components of the parliamentary discourse on terrorism as well as major actors and social networks involved. It covers political responses to a range of terrorism-related issues as well as factors influencing policy-makers’ engagement, including political affiliations and gender. SweTerror also develops an online research portal, featuring the complete research material and searchable audio made readily accessible for further exploration. Long-term, the project establishes a model for combining extraction technologies (speech recognition and analysis) for audiovisual parliamentary data with text mining and HSS interpretive methods and the portal is designed to serve as a prototype for other similar projects.
|
|
| 10. |
- Eriksson, Mats, Professor, 1959-, et al.
(författare)
-
Neurophysiological and behavioural measures of pain during neonatal hip examination
- 2019
-
Konferensbidrag (refereegranskat)abstract
- Background: In Sweden, all newborns are examined before discharge from the maternity ward to rule out innate abnormalities. Parts of this procedure, such as the hip examination, appear to cause pain and discomfort. Pain in newborns can have both short- and long-term negative consequences and preventing and treating pain is therefore an important part of medical care. There are several ways to recognize and assess pain in newborn infants. Scales such as the Premature Infant Pain Profile-Revised (PIPP-R) are recommended, but recently physiological and neurophysiological measures, e.g. Near-infrared spectroscopy (NIRS) and Galvanic Skin Response (GSR) have been suggested to have pain-assessing properties.Aim: The aim of the study was to test the hypothesis that neonatal hip examination causes pain in newborns. Method: The infant was placed on an examination table and a video camera was placed so the face of the newborn was filmed. A pulse oximeter probe, NIRS optodes and GSR electrodes were attached to the infant. Heart auscultation was chosen to be used as a non-painful comparative to hip examination.Results: The results showed higher pain scoring for the hip examination than for the heart auscultation. NIRS, showed a significant difference in HbO2 on both sides of cortex. Mean PIPP-R went from 3.0 during the heart auscultation to 8.1 during the hip examination. GSR analyses showed significant increase in area under small peaks during the hip examination. Conclusion: We conclude that neonatal hip examinations are painful and that the pain should be treated, e.g. with oral sweet solution.
|
|
