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  • 51.
    Ghareh Baghi, Arash
    et al.
    Linköping University, Linköping, Sweden.
    Dutoit, Thierry
    Mons University, Mons, Belgium.
    Ask, Per
    Linköping University, Linköping, Sweden.
    Sörnmo, Leif
    Lund University, Lund, Sweden .
    Detection of systolic ejection click using time growing neural network2014Inngår i: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 36, nr 4, s. 477-483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a novel neural network for classification of short-duration heart sounds: the time growing neural network (TGNN). The input to the network is the spectral power in adjacent frequency bands as computed in time windows of growing length. Children with heart systolic ejection click (SEC) and normal children are the two groups subjected to analysis. The performance of the TGNN is compared to that of a time delay neural network (TDNN) and a multi-layer perceptron (MLP), using training and test datasets of similar sizes with a total of 614 normal and abnormal cardiac cycles. From the test dataset, the classification rate/sensitivity is found to be 97.0%/98.1% for the TGNN, 85.1%/76.4% for the TDNN, and 92.7%/85.7% for the MLP. The results show that the TGNN performs better than do TDNN and MLP when frequency band power is used as classifier input. The performance of TGNN is also found to exhibit better immunity to noise.

  • 52.
    Ghareh Baghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Linköping University, Linköping, Sweden.
    Ekman, I.
    Linköping University, Linköping, Sweden.
    Ask, P.
    Linköping University, Linköping, Sweden.
    Nylander, E.
    Linköping University, Linköping, Sweden.
    Janerot-Sjoberg, B.
    Karolinska University Hospital, Stockholm, Sweden.
    Assessment of aortic valve stenosis severity using intelligent phonocardiography2015Inngår i: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 198, s. 58-60Artikkel i tidsskrift (Annet vitenskapelig)
  • 53.
    Ghareh Baghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A Deep Machine Learning Method for Classifying Cyclic Time Series of Biological Signals Using Time-Growing Neural Network2018Inngår i: IEEE Transactions on Neural Networks and Learning Systems, ISSN 2162-237X, E-ISSN 2162-2388, Vol. 29, nr 9, s. 4102-4115, artikkel-id 8066455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel method for learning the cyclic contents of stochastic time series: the deep time-growing neural network (DTGNN). The DTGNN combines supervised and unsupervised methods in different levels of learning for an enhanced performance. It is employed by a multiscale learning structure to classify cyclic time series (CTS), in which the dynamic contents of the time series are preserved in an efficient manner. This paper suggests a systematic procedure for finding the design parameter of the classification method for a one-versus-multiple class application. A novel validation method is also suggested for evaluating the structural risk, both in a quantitative and a qualitative manner. The effect of the DTGNN on the performance of the classifier is statistically validated through the repeated random subsampling using different sets of CTS, from different medical applications. The validation involves four medical databases, comprised of 108 recordings of the electroencephalogram signal, 90 recordings of the electromyogram signal, 130 recordings of the heart sound signal, and 50 recordings of the respiratory sound signal. Results of the statistical validations show that the DTGNN significantly improves the performance of the classification and also exhibits an optimal structural risk. 

  • 54.
    Ghareh Baghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Babic, A.
    University of Bergen, Norway.
    An artificial intelligent-based model for detecting systolic pathological patterns of phonocardiogram based on time-growing neural network2019Inngår i: Applied Soft Computing, ISSN 1568-4946, E-ISSN 1872-9681, Vol. 83, artikkel-id 105615Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel hybrid model for classifying time series of heart sound signal using time-growing neural network. The proposed hybrid model takes segmental behaviour of heart sound signal into account by combining two different deep learning methods, the Static and the Moving Time-Growing Neural Network, which we call STGNN and MTGNN, respectively. Flexibility of the model in learning both deterministic and stochastic segments of signal allows it to learn those complicated characteristics of heart sound signal caused by any obstruction on semilunar heart valve. The model is trained to distinguish between a patient group and a reference group. The patient group is comprised of the subjects with the semilunar heart valve abnormalities including aortic stenosis, pulmonary stenosis and bicuspid aortic valve, whereas the reference group which is composed of the individuals with the heart abnormalities other than those of the reference group or the healthy ones. The model is validated using two different databases: one comprised of 140 children with various heart conditions, and the other one constituted of 50 elderly patients with aortic stenosis. Both the datasets were collected from the referrals to the University hospitals. The overall accuracy and sensitivity of the model are estimated to be 84.2% and 82.8%, respectively. The results show that the model exhibits sufficient capability to distinguish between the patient and the reference group in such a demanding clinical application. 

  • 55.
    Ghareh Baghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sepehri, A. A.
    CAPIS Biomedical Research and Development Centre, Mon, Belgium.
    Babic, A.
    Linköping University.
    Forth heart sound detection using backward time-growing neural network2020Inngår i: IFMBE Proceedings, Springer Verlag , 2020, s. 341-345Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel method for processing heart sound signal for screening forth heart sound (S4). The proposed method is based on time growing neural network with a new scheme, which we call the Backward Time-Growing Neural Network (BTGNN). The BTGNN is trained for detecting S4 in recordings of heart sound signal. In total, 83 children patients, referred to a children University hospital, participated in the study. The collected signals are composed of the subjects with and without S4 for training and testing the method. Performance of the method is evaluated using the Leave-One-Out and the repeated random sub sampling methods. The accuracy/sensitivity of the method is estimated to be 88.3%/82.4% and the structural risk is calculated to be 18.3% using repeated random sub sampling and the A-Test methods, respectively.

  • 56.
    Gharehbaghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Linköping University, Linköping, Sweden .
    Ask, P.
    Linköping University, Linköping, Sweden .
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Babic, A.
    Linköping University, Linköping, Sweden.
    A Novel Model for Screening Aortic Stenosis Using Phonocardiogram2015Inngår i: IFMBE Proceedings, Volume 48, Springer , 2015, Vol. 48, s. 48-51Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This study presents an algorithm for screening aortic stenosis, based on heart sound signal processing. It benefits from an artificial intelligent-based (AI-based) model using a multi-layer perceptron neural network. The AI-based model learns disease related murmurs using non-stationary features of the murmurs. Performance of the model is statistically evaluated using two different databases, one of children and the other of elderly volunteers with normal heart condition and aortic stenosis. Results showed a 95% confidence interval of the high accuracy/sensitivity thus exhibiting a superior performance to a cardiologist who relies on the conventional auscultation. The study suggests including the heart sound signal in the clinical decision making due to its potential to improve the screening accuracy.

  • 57.
    Gharehbaghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dutoit, T.
    Mons University, Mons, Belgium .
    Sepehri, A. A.
    CAPIS Biomedical Research and Department Center, Mons, Belgium.
    Kocharian, A.
    Tehran University of Medical Sciences, Tehran, Iran.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A Novel Method for Screening Children with Isolated Bicuspid Aortic Valve2015Inngår i: Cardiovascular Engineering and Technology, ISSN 1869-408X, E-ISSN 1869-4098, Vol. 6, nr 4, s. 546-556Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel processing method for heart sound signal: the statistical time growing neural network (STGNN). The STGNN performs a robust classification by merging supervised and unsupervised statistical methods to overcome non-stationary behavior of the signal. By combining available preprocessing and segmentation techniques and the STGNN classifier, we build an automatic tool for screening children with isolated BAV, the congenital heart malformation which can lead to serious cardiovascular lesions. Children with BAV (22 individuals) and healthy condition (28 individuals) are subjected to the study. The performance of the STGNN is compared to that of a time growing neural network (CTGNN) and a conventional support vector (CSVM) machine, using balanced repeated random sub sampling. The average of the accuracy/sensitivity is estimated to be 87.4/86.5 for the STGNN, 81.8/83.4 for the CTGNN, and 72.9/66.8 for the CSVM. Results show that the STGNN offers better performance and provides more immunity to the background noise as compared to the CTGNN and CSVM. The method is implementable in a computer system to be employed in primary healthcare centers to improve the screening accuracy. 

  • 58.
    Gharehbaghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    An Internet-Based Tool for Pediatric Cardiac Disease Diagnosis using Intelligent Phonocardiography2016Inngår i: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST, 2016, Vol. 169, s. 443-447Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper suggests an internet-based tool for cardiac diagnosis in children. The main focus of the paper is the intelligent algorithms for processing heart sounds that are implementable on an internet platform. The algorithms are based on the statistical classification methods, tailored for the heart sound signal processing. The algorithms, applied to 55 healthy and 45 children with congenital heart diseases. The accuracy of the algorithm is estimated to be 86.0 % in screening the children with pathological murmurs, and 95.7 %, 92.9 % and 91.4 % in detecting the children with aortic stenosis, pulmonary stenosis and mitral regurgitation, respectively, showing an acceptable performance to be employed as a decision support tool.

  • 59.
    Gharehbaghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sepehri, A. A.
    CAPIS Biomedical Research and Department Center, Mons, Belgium.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Babic, A.
    Linköping University, Sweden.
    A hybrid machine learning method for detecting cardiac ejection murmurs2017Inngår i: IFMBE Proceedings, Springer Verlag , 2017, s. 787-790Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel method for detecting cardiac ejection murmurs from other pathological and physiological heart murmurs in children. The proposed method combines a hybrid model and a time growing neural network for an improved detection even in mild condition. Children with aortic stenosis and pulmonary stenosis comprised the patient category against the reference category containing mitral regurgitation, ventricular septal defect, innocent murmur and normal (no murmur) conditions. In total, 120 referrals to a children University hospital participated to the study after giving their informed consent. Confidence interval of the accuracy, sensitivity and specificity is estimated to be 87.2% ̶ 88.8%, 83.4% ̶ 86.9% and 88.3% ̶ 90.0%, respectively. 

  • 60.
    Gharehbaghi, Arash
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sepehri, A. A.
    CAPIS Biomedical Research and Development Center, Mon, Belgium.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Babic, A.
    Linköping University, Sweden.
    Intelligent phonocardiography for screening ventricular septal defect using time growing neural network2017Inngår i: Studies in Health Technology and Informatics, vol 238, IOS Press , 2017, Vol. 238, s. 108-111Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This paper presents results of a study on the applicability of the intelligent phonocardiography in discriminating between Ventricular Spetal Defect (VSD) and regurgitation of the atrioventricular valves. An original machine learning method, based on the Time Growing Neural Network (TGNN), is employed for classifying the phonocardiographic recordings collected from the pediatric referrals to a children hospital. 90 individuals, 30 VSD, 30 with the valvular regurgitation, and 30 healthy subjects, participated in the study after obtaining the informed consents. The accuracy and sensitivity of the approach is estimated to be 86.7% and 83.3%, respectively, showing a good performance to be used as a decision support system. .

  • 61.
    Gholamhosseini, H.
    et al.
    Auckland University of Technology, Department of Electrical and Electronic Engineering, Auckland, New Zealand.
    Baig, M. M.
    Auckland University of Technology, Department of Electrical and Electronic Engineering, Auckland, New Zealand.
    Connolly, M. J.
    Freemasons' Department of Geriatric Medicine, University of Auckland and North Shore Hospital, Takapuna, Auckland, New Zealand.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A multifactorial falls risk prediction model for hospitalized older adults2014Inngår i: 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014, 2014, s. 3484-3487Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Ageing population worldwide has grown fast with more cases of chronic illnesses and co-morbidity, involving higher healthcare costs. Falls are one of the leading causes of unintentional injury-related deaths in older adults. The aim of this study was to develop a robust multifactorial model toward the falls risk prediction. The proposed model employs real-time vital signs, motion data, falls history and muscle strength. Moreover, it identifies high-risk individuals for the development falls in their activity of daily living (ADL). The falls risk prediction model has been tested at a controlled-environment in hospital with 30 patients and compared with the results from the Morse fall scale. The simulated results show the proposed algorithm achieved an accuracy of 98%, sensitivity of 96% and specificity of 100% among a total of 80 intentional falls and 40 ADLs. The ultimate aim of this study is to extend the application to elderly home care and monitoring.

  • 62.
    Gholamhosseini, H.
    et al.
    Auckland University of Technology, New Zealand.
    Baig, M.
    Auckland University of Technology, New Zealand.
    Maratas, J.
    Auckland University of Technology, New Zealand.
    Mirza, F.
    Auckland University of Technology, New Zealand.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Obesity Risk Assessment Model Using Wearable Technology with Personalized Activity, Calorie Expenditure and Health Profile2019Inngår i: Studies in Health Technology and Informatics, ISSN 0926-9630, E-ISSN 1879-8365, Vol. 261, s. 91-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a worldwide increase in the rate of obesity and its related long-term conditions, emphasizing an immediate need to address this modern-age global epidemic of healthy living. Moreover, healthcare spending on long-term or chronic care conditions such as obesity is increasing to the point that requires effective interventions and advancements to reduce the burden of the healthcare. This research focuses on the early risk assessment of overweight/obesity using wearable technology. We establish an individualised health profile that identifies the level of activity and current health status of an individual using real-time activity and vital signs. We developed an algorithm to assess the risk of obesity using the individual's current activity and calorie expenditure. The algorithm was deployed on a smartphone application to collect wearable device data, and user reported data. Based on the collected data, the proposed application assesses the risk of obesity/overweight, measures the current activity level and recommends an optimized calorie plan.

  • 63.
    Gholamhosseini, H.
    et al.
    Auckland University of Technology, Auckland, New Zealand.
    Baig, M.
    Auckland University of Technology, Auckland, New Zealand.
    Rastegar, S.
    Auckland University of Technology, Auckland, New Zealand.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Cuffless blood pressure estimation using pulse transit time and photoplethysmogram intensity ratio2018Inngår i: Studies in Health Technology and Informatics, vol 249, IOS Press , 2018, s. 77-83Konferansepaper (Fagfellevurdert)
    Abstract [en]

    High blood pressure (BP) is one of the common risk factors for heart disease, stroke, congestive heart failure, and kidney disease. An accurate, continuous and cuffless BP monitoring technique could help clinicians improve the rate of prevention, detection, and treatment of hypertension and related diseases. Pulse transit time (PTT) has attracted interest as an index of BP changes for cuffless BP measurement techniques. Currently, PPT-based BP measurement approaches have improved and are able to relieve the discomfort associated with an inflated cuff such as that used in auscultatory and oscillometric BP measurement techniques. However, PTT can only track the BP variation in high frequency (HF) which limits the true representation of BP changes. This paper presents a continuous and cuffless BP monitoring method based on multiparameter fusion. We used photoplethysmogram (PPG) and a two-lead electrocardiogram (ECG) and employed an algorithm based on PTT and the PPG intensity ratio (PIR) to continuously track BP in both high and low frequencies and estimate systolic and diastolic BP. 

  • 64.
    Gransjön Craftman, A.
    et al.
    Sophiahemmet University, Stockholm, Sweden.
    Marmstål Hammar, Lena
    Mälardalens högskola, Akademin för hälsa, vård och välfärd, Hälsa och välfärd. Karolinska Institutet, Stockholm, Sweden.
    von Strauss, E.
    Stockholm University, Stockholm, Sweden.
    Hillerås, P.
    Sophiahemmet University, Stockholm, Sweden .
    Westerbotn, M.
    Sophiahemmet University, Stockholm, Sweden .
    Unlicensed personnel administering medications to older persons living at home: A challenge for social and care services2015Inngår i: International Journal of Older People Nursing, ISSN 1748-3735, E-ISSN 1748-3743, Vol. 10, nr 3, s. 201-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Administration of medication to care recipients is delegated to home-care assistants working in the municipal social care, alongside responsibility for providing personal assistance for older people. Home-care assistants have practical administration skills, but lack formal medical knowledge. Aim: The aim of this study was to explore how home-care assistants perceive administration of medication to older people living at home, as delegated to them in the context of social care. Methods: Four focus groups consisting of 19 home-care assistants were conducted. Data were analysed using qualitative content analysis. Results: According to home-care assistants, health and social care depends on delegation arrangements to function effectively, but in the first place it relieves a burden for district nurses. Even when the delegation had expired, administration of medication continued, placing the statutes of regulation in a subordinate position. There was low awareness among home-care assistants about the content of the statutes of delegation. Accepting delegation to administer medications has become an implicit prerequisite for social care work in the municipality. Conclusions: Accepting the delegation to administer medication was inevitable and routine. In practice, the regulating statute is made subordinate and consequently patient safety can be threatened. The organisation of health and social care relies on the delegation arrangement to meet the needs of a growing number of older home-care recipients. Implications for practice: This is a crucial task which management within both the healthcare professions and municipal social care needs to address, to bridge the gap between statutes and practice, to create arenas for mutual collaboration in the care recipients' best interest and to ensure patient safety. 

  • 65.
    Granstedt, Fredrik
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Folke, Mia
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Bäcklund, Ylva
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Hök, Bertil
    Hök Instrument AB, Sweden.
    Gas sensor with electroacoustically coupled resonator2001Inngår i: Sensors and Actuators, ISSN 0925-4005, Vol. 78, s. 161-165Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new configuration for a gas sensor is demonstrated. The configuration consists of an electroacoustic element coupled to an acoustic resonator, such as Kundt's tube, exhibiting a resonance frequency that is related to the velocity of sound, which, in turn is a function of the molecular mass of the gas within the resonator. Electrical impedance measurements were performed, whereby a resonance peak attributable to the resonator was identified. Contributing effects to the quality factor, Q, of the resonance, was analyzed. Predictable shifts of the resonance frequency were observed when adding CO2 and He to air, and when varying the resonator length. Linearity within the experimental accuracy was confirmed. The new sensor configuration offers the potential advantages of smaller size, improved dynamic response, and lower cost. © 2001 Elsevier Science B.V. All rights reserved.

  • 66.
    Hagblad, Jimmie
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Lindberg, Lars-Göran
    Linköpings Universitet, IMT.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Assessment of the optical interference in a PPG-LDF system used for estimation of tissue blood flow2011Inngår i: IFMBE PROCEEDINGS: 15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2011; Aalborg; 14 June 2011 through 17 June 2011 / [ed] Kim Dremstrup, 2011Konferansepaper (Fagfellevurdert)
  • 67.
    Hagblad, Jimmie
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Lindberg, Lars-Göran
    Linköpings Universitet, IMT.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Long-term monitoring of blood flow at different depths using LDF and PPG - issues to considerManuskript (preprint) (Annet vitenskapelig)
  • 68.
    Hellstrom, Per Anders Rickard
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Implementation and Calibration of Force Sensing Resistors in Insoles2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction

    Many researchers have built pedobarography measurement systems [1]. Pedobarography, the study of forces interacting between the plantar surface of the feet and a supporting surface, can be used in many applications. Examples are analysis of gait and posture in for example orthotics design and monitoring of rehabilitation. Force sensing resistors (FSR) measure approximately the ground reaction force which is the force acting on the foot from the insole. Low sensor height, high linearity and good durability are three important sensor properties. FSRs are down to 0.2mm thick but can be non-linear and they can break easily if implemented wrongly. How can the FSRs be implemented in insoles and calibrated to overcome these sensor type shortcomings?

    Implementation

    Discrete FSRs are often placed at the heel, inside and outside of the metatarsal pad and the big toe pad. It is vital to protect the boundary of the active sensor area. If the boundary is exposed to too much mechanical strain it will rapidly break down. This is because the upper and lower layers of the sensor get short-circuited. First the sensor will show intermittent maximum values and later stop working at all. One solution is to remove insole material right under the sensor boundary to relieve it from mechanical strain [2].

    Calibration

    The FSR manufacturers recommend using at least four different loads for the calibration and be aware that static load makes the sensor drift over time. It is important to choose a similar calibration procedure as the application it will be used for, e.g. dynamic calibration if the application is measurement while walking. A load cell should be used for calibrating the FSR. Linear or exponential regression are not recommended. Three or fourth power polynomials have shown to produce acceptable errors [3].

    Discussion

    FSRs have two less than ideal properties regarding linearity and durability. The lifetime of the sensor can be increased by taking special care of not exposing the active sensor area boundary to mechnical stress. Calibration should be done dynamically if the application is e.g. measurment while walking. Three power, or higher, polynomials are recomended for the regression.

    References

    • [1] N. Hegde, et al., A Comparative Review of Footwear-Based Wearable Systems. Electronics 5(3), (2016).
    • [2] P. A. R. Hellström, Wireless Wearable Measurement System Based on Pedobarography for Monitoring of Health. Lic. Thes., (2016).
    • [3] J. M. Brimacombe, et al., Effect of calibration method on Tekscan sensor accuracy. J. Biomech. Eng. 131(3), (2009).
  • 69.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Carlén Eriksson, Lennie
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Scharff Willners, Jonatan
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Intelligent Wireless Body Area Network System for Human Motion Analysis2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Human motion analysis provides several important applications. Examples are fall risk assessment, sports biomechanics, physical activity monitoring and rehabilitation. This work in progress paper proposes an intelligent wireless body area network system for motion and gait symmetry analysis. A Bluetooth network with accelerometers, gyroscopes and in-shoe force sensing resistors gathers data and sends it to a web server after intelligent pre-processing and filtering. The system is flexible and adaptable for different use cases including combinations of gait analysis, gait symmetry and pressure measurements between foot and shoe.

  • 70.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Carried Weight Affects Walking Speed Monitoring with the IngVaL System2019Inngår i: The Sixteenth International Conference on Wearable Micro and Nano Technologies for Personalized Health, pHealth 2019, June 10-12, Studies in health technology and informatics, volume 261, pages 317-320, 2019 / [ed] Bernd Blobel, Mauro Giacomini, Nieuwe Hemweg 6B 1013 BG Amsterdam, The Netherlands: NLM (Medline) , 2019, Vol. 261, s. 317-320Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Earlier work has shown that the IngVaL pedobarography system can estimate walking speed during indoor walking using only three forefoot sensors. The aim of this study was to examine if monitoring of walking speed using data from these three forefoot sensors is affected of the weight a person carries, if the person performs a walk in a set speed on the treadmill. Shoe insoles with force sensing resistors were connected to an electronic unit for signal conditioning and sampling and then the data was sent via Bluetooth to a tablet. Fifteen test persons walked five times each carrying five different weights on the treadmill at 1 m/s. The force-time integrals for the sum of the three forefoot sensors were calculated. This study shows that the force-time integrals for the three forefoot sensors shows a linear relationship with the carried weight as long as the person is not fatigued.

  • 71.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    FOLKE, MIA
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Monitoring of Carried Weight During Walk Using a Wearable Pedobarography System2019Inngår i: The Fifth International Conference on Smart Portable, Wearable, Implantable and Disability-oriented Devices and Systems, SPWID 2019, July 28-August 2, pages 5-8, 2019 / [ed] Jaime Lloret, Universitat Politecnica de Valencia, Spain, IARIA, PO Box 7827, Wilmington, DE 19803, USA: International Academy, Research and Industry Association (IARIA), 2019, s. 5-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Personal health monitoring is advantageous in heavy work environments to reduce the risk of wear and tear and acute injuries. The study of forces between the plantar surface of the foot and a supporting structure, pedobarography, is a  promising candidate for monitoring carried weight during walk. The aim of this study was to evaluate the cost effective pedobarography measurement system, IngVaL. Two aspects are evaluated, namely, how well IngVaL can monitor carried weight during walk and if the novel implementation increased the durability. Fifteen test persons made five treadmill walks with a carried weight of 10, 20, 0, 15, and 5 kg. The equipoise analysis method was used. The Root Mean Square Error (RMSE) for estimation of the carried weight was 13.8 kg. A study with the earlier version of the measurement system had a RMSE of 23.3 kg. The earlier system, as well as commercial systems using this kind of sensors, have problems with sensor durability. The new sensor implementation, where the active sensor area boundary was no longer affected by mechanical stress, resulted in no broken sensors. This study shows an increased performance of carried weight estimation compared with earlier work, together with an improved sensor durability.

  • 72.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Wearable Weight Estimation System2015Inngår i: Procedia Computer Science, vol. 64, 2015, Vol. 64, s. 146-152Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Heavy working conditions, as well as sedentary behaviour, are risk factors for health. There is a lack of wearable measurement systems for monitoring carried loads while walking. Pedobarography, the study of force fields acting between the plantar surface of the foot and a supporting surface, is supposed to be useable for estimating carried loads. Purpose. The aim of this paper is to present a novel method for selecting appropriate measurement samples for weight estimation of carried load during walk and a wearable system, based on pedobarography, consisting of commercial off the shelf components. The main idea is to choose samples when half of the total weight is on the forward sensors and the other half is on the heel sensor “equipoise” in one foot while the other foot not touches the ground. Methods. The system consists of insoles with force sensing resistors, data acquisition with IOIO-OTG and analysis in Excel. Each subject was weighed on an electronic floor scale. Three walks were performed on level ground. The first walk without any added load and then with two increases of carried load. Equipoise was defined as having half the weight distributed on the heel and the other half over the metatarsal pad. An equipoise value of 0.5 represents equilibrium regarding the weight distribution on one foot, with the other foot in the air. Samples were chosen in the equipoise region of 0.5±0.1 and then the average of the samples collected during one minute estimated the total weight. Results. The system can detect increases in carried loads but has a tendency to overestimate them. The estimated value was always larger with increased weight but the system was not always linear. The average overestimation error was 16.7 kg. Discussion. This study shows that this type of wearable system is usable for estimating carried load during walk after calibration of the system to the body weight force distribution on the sensors. There is still need for future development to obtain real-time analysis and direct feedback. A smaller and lighter measurement system is also desirable. Conclusion. This study shows that the novel method, equipoise, is usable for selecting appropriate measurement samples for weight estimation of carried load during walk. This study also shows that the wearable system, consisting of commercial off the shelf components, can be used for these measurements. However, there is a tendency to overestimate the loads.

  • 73.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Åkerberg, Anna
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    FOLKE, MIA
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Mälardalens högskola, Akademin för hälsa, vård och välfärd.
    Evaluation of the IngVaL Pedobarography System for Monitoring of Walking Speed2018Inngår i: Healthcare Informatics Research, ISSN 2093-3681, E-ISSN 2093-369X, ISSN 2093-3681, Vol. 24, nr 2, s. 118-124Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives

    Walking speed is an important component of movement and is a predictor of health in the elderly. Pedobarography, the study of forces acting between the plantar surface of the foot and a supporting surface, is an approach to estimating walking speed even when no global positioning system signal is available. The developed portable system, Identifying Velocity and Load (IngVaL), is a cost effective alternative to commercially available pedobarography systems because it only uses three force sensing resistors. In this study, the IngVaL system was evaluated. The three variables investigated in this study were the sensor durability, the proportion of analyzable steps, and the linearity between the system output and the walking speed.

    Methods

    Data was collected from 40 participants, each of whom performed five walks at five different self-paced walking speeds. The linearity between the walking speed and step frequency measured with R2 values was compared for the walking speed obtained ‘A’ only using amplitude data from the force sensors, ‘B’ that obtained only using the step frequency, and ‘C’ that obtained by combining amplitude data for each of the 40 test participants.

    Results

    Improvement of the wireless data transmission increased the percentage of analyzable steps from 83.1% measured with a prototype to 96.6% for IngVaL. The linearity comparison showed that the methods A, B, and C were accurate for 2, 15, and 23 participants, respectively.

    Conclusions

    Increased sensor durability and a higher percentage of analyzed steps indicates that IngVaL is an improvement over the prototype system. The combined strategy of amplitude and step frequency was confirmed as the most accurate method.

  • 74.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Åkerberg, Anna
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Walking Intensity Estimation with a Portable Pedobarography System2016Inngår i: Studies in Health Technology and Informatics, IOS Press , 2016, Vol. 224, s. 27-32Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this pilot study was to investigate the possibility to find a correlation between the output from a portable pedobarography system and the walking intensity expressed as walking speed. The system uses shoe insoles with force sensing resistors and wireless transmission of the data via Bluetooth. The force-time integral, at the toe-off phase of the step, for the force sensors in the forward part of the right foot was used to measure impulse data for 10 subjects performing walks in three different walking speeds. This data was then corrected by multiplication with the step frequency. This pilot study indicates that the portable pedobarography system output shows a linear relationship with the walking intensity expressed as walking speed on an individual level.

  • 75.
    Hellstrom, Per Anders Rickard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Åkerberg, Anna
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Folke, Mia
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Posture Sensor as Feedback when Lifting Weights2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction

    When lifting a package or during strength training, right posture of the back is important to avoid back pain. Different sensor solutions to measure posture of the back are presented in research articles and patents. The aim of this study was to investigate the possibility of using Lumo Lift as a device of giving feedback of good posture when lifting weights.

    Method

    Lumo Lift (Lumo Body Tech, Inc, USA) is an activity tracker aimed to for example guide the carrier to good posture. The small device is attached to the clothes using a magnetic clasp. It is calibrated to the user's good posture and vibrates when the posture is inaccurate. In this study the angle, in which the Lumo Lift is allowed to tilt before the device vibrates, was investigated. The device was placed at the top of a ruler and calibrated in upright position. Thereafter the ruler was tilted and the angle when the equipment vibrated was noted. Two different speeds of the tilts were performed. One speed simulating the normal speed of an inaccurate tilting torso when lifting weights. And one slow speed. Two Lumo Lifts were tilted 20 times forward and backwards, respectively.

    Result

    In normal speed the measured angle was between 6 and 25 degrees, when tilted forward, except two times when one of the devices gave no vibration during the whole tilt of 90 degrees. When tilted backwards the angle was between 8 and 32 degrees. During slow tilt the angle varied from 5 to 13 degrees forward and 4 to 13 degrees backwards.

    Discussion and conclusion

    Angle tilted before vibration is too large in normal tilting speed. This study indicates that Lumo Lift is not suitable of giving posture feedback during lifting in daily life.

  • 76.
    Hellström, Per Anders Rickard
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Wearable Pedobarography System for Monitoring of Walk Related Parameters2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Health care costs have increased over the last decades due to an ageing population. Therefore, research in personal health monitoring (PHM) has increased in response to this. PHM has advantages such as mobility (monitoring of health at work or at home), early detection of health problems enabling preventive health measures and a reduction of health care cost. Human motion analysis, using for example pedobarography (PBG), is an important subcategory of PHM. PBG is used to study the force fields acting between the plantar surface of the foot and a supporting surface. Gait and posture analysis, prosthetics evaluation and monitoring of recovery from injury or disease are examples of PBG applications. Portable PBG can be performed using force sensing resistors built into the insole inside the shoe.

     In accordance with this, the research aim for this thesis is to design, build and evaluate a wireless wearable measurement system based on PBG for monitoring of walk related parameters. Monitoring of carried weight and walking speed were chosen as the applications for validation of the system. Motivations for choosing these applications are that there is a lack of a wearable system for monitoring of weight while walking and a possible combination with accelerometers to improve the estimation of walking speed. Both walking speed and weight are important factors for estimating energy expenditure. A portable system, that estimates weight while walking, enables monitoring of heavy working conditions.

    The main research contributions include design of a PBG measurement system with a sensor implementation resulting in good sensor durability, several novel methods for weight estimation during walk and a novel method for analysing walking intensity and relating it to walking speed. The research results show that the new PBG system, in combination with the novel analysing methods, are suitable for use in wearable systems for monitoring of health related walk parameters.

  • 77.
    Hellström, Per Anders Rickard
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Wireless Wearable Measurement System Based on Pedobarography for Monitoring of Health2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Health care costs have increased over the last decades due to an ageing population. Therefore, research in personal health monitoring (PHM) has increased in response to this. PHM has advantages such as mobility (monitoring of health at work or at home), early detection of health problems enabling preventive health measures and a reduction of health care cost. Human motion analysis, using for example inertial measurement units and pedobarography, is an important subcategory of PHM. Pedobarography (PBG) is the study of pressure fields acting between the plantar surface of the foot and a supporting surface. Gait and posture analysis, prosthetics evaluation and monitoring of recovery from injury or disease are examples of PBG applications. Portable PBG can be performed using force sensing resistors built into the insole inside the shoe.

    In accordance with this, the research goal for this licentiate thesis is to design, build and evaluate a wireless wearable measurement system based on pedobarography for monitoring of health. In order to fulfil the objectives of the research, literature studies were done and problems with existing in-shoe system solutions were identified. Thus, it was found that further opportunities existed for new designs of PBG systems which take these problems into account. Cross-sectional test case studies were used for validation. The research area is multidisciplinary and encompasses biomedical measurements, electronics and computer science.

    The main research contributions include design and implementation of a PBG measurement system consisting of commercial off the shelf components, a novel method for selecting measurement samples for weight estimation of carried load during walk, and a novel method for analysing walking intensity using force-time integrals at the toe-off phase of the step. The research results suggest that the new PBG system, in combination with the two novel analysing methods, are suitable for use in wearable systems for monitoring of health. Personal health measurements are done to help decision making related to health. Thus, the future work will strive towards designing different decision support systems.

  • 78.
    Hilmersson, Anette
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Multisensor Stress Monitoring For Non-Stationary Subjects2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Monitoring stress in real-time, in a non-laboratory environment can be benecial in several applications. One of these, which have been the motivation for this thesis, is to to perform this measurement during Attention decit hyperactivity disorder (ADHD) diagnosis. Monitoring several physiological responses to internal or external stimuli in a single soft-real-time system is nota solution widely used in an application like this. The thesis starts by studying several stress related responses in detail. Sensors for all of the responses are not implemented nor is it possible toimplement in to the desired system. After the study is was decided to implement two measurement modules. The first a Photo-plethysmogrophy (PPG) measurement module to measure heart rate and also estimate breathing. This module is prepared for estimating arterial blood oxygen levels but the calculation or verification have not been done. The second is Skin Conductance (SC) measurement module and in to both ofthese add a temperature sensor to measure the temperature of the skin. Time constraints limit the SC module to only be presented in theory. The PPG module on the other hand have been realisedin a prototype. This prototype performs the measurement in transmissive mode on the left earlobe, which leaves the hands free and it does not affect the hearing on that ear. The prototype giveout acceptable signal quality when good contact with the measurement site is achieved. The signalinterpretation, such as performing the signal analysis to count the beats per minute, is outside thescope of this thesis and will therefore not be presented but the signals can be seen in figures.

  • 79. Hirvikoski, Tatja
    et al.
    Nordenström, Anna
    Lindholm, Torun
    Mälardalens högskola, Institutionen för samhälls- och beteendevetenskap.
    Lindblad, Frank
    Ritzén, Martin
    Wedell, Anna
    Lajic, Svetlana
    Long-term effects of prenatal treatment with glucocorticoids in CAH2006Konferansepaper (Fagfellevurdert)
  • 80.
    Hollmark, Malin
    et al.
    Uppsala universitet, Industriell teknik.
    Lefevre Skjöldebrand, Anna
    Andersson, Christoffer
    Uppsala universitet, Industriell teknik.
    Lindblad, Ragnar
    Technology Ready to be Launched, but is there a Payer?: Challenges for Implementing eHealth in Sweden2015Inngår i: Studies in Health Technology and Informatics, ISSN 0926-9630, E-ISSN 1879-8365, Vol. 211, s. 57-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of a sustainable, high-quality, affordable health care is today a high priority for many actors in the society. This is to ensure that we will continue to afford to care for the growing portion of elderly in our population. One solution is to enable the individual's power over her own health or illness, and participation in her own care. There are evidently opportunities with the rapid development of eHealth and wearable sensors. Tracking and measuring vital data can help to keep people out of the hospital. Loads of data is generated to help us understand disease, to provide us with early diagnostics and warnings. It is providing us with possibilities to collect and capture the true health status of individuals. Successful technologies demonstrate savings, acceptance among users and improved access to healthcare. But there are also challenges. Implementing new technologies in health care is difficult. Researchers from around the world are reporting on similar problems, such as reimbursement, interoperability, usability and regulatory issues. This paper will discuss a few of these implementation challenges as well as a few of the efforts in meeting them. To conclude, eHealth solutions can contribute to patient empowerment and a sustainable health care. Our assumption is however, that as long as we do not face the implementation challenges and invest in overcoming the pressing obstacles, society will not be able, or willing, to pay for the solutions.

  • 81.
    Hök, Bertil
    et al.
    Hök Instrument AB, Sweden.
    Ljungblad, Jonas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Hök Instrument AB, Sweden.
    Kaisdotter Andersson (Jonsson), Annika
    Hök Instrument AB, Sweden.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Enlund, Mats
    Västerås Sjukhus, Västerås, Sweden.
    Unobtrusive and Highly Accurate Breath Alcohol Analysis Enabled by Improved Methodology and Technology2014Inngår i: Journal of Forensic Investigation, ISSN 2330-0396, Vol. 2, nr 4, s. 1-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study objective was to evaluate a novel method and technology for unobtrusive determination of breath alcohol in relation to current industrial accuracy standards. The methodology uses carbon dioxide as a tracer gas detected by sensor technology based on infrared spectroscopy. Part one of the investigation was to analyse the performance of hand-held prototype devices and included tests of resolution, unit-to-unit variation during calibration, response to alcohol containing gas pulses created with a wet gas simulator, and cross sensitivity to other substances. In part two of the study, 30 human participants provided 1465 breath tests in both unobtrusive and obtrusive use modes. The results of both parts of the study indicate that the prototype devices exceeded present industrial accuracy requirements. The proposed methodology and technology eliminate the previous contradiction between unobtrusiveness and high accuracy.

  • 82.
    Johansson-Pajala, Rose-Marie
    et al.
    Mälardalens högskola, Akademin för hälsa, vård och välfärd, Hälsa och välfärd.
    Thommes, K.
    Paderborn University, Paderborn, Germany.
    Hoppe, J. A.
    Paderborn University, Paderborn, Germany.
    Tuisku, O.
    Lappeenranta University of Technology, Lahti, Finland.
    Hennala, L.
    Lappeenranta University of Technology, Lahti, Finland.
    Pekkarinen, S.
    Lappeenranta University of Technology, Lahti, Finland.
    Melkas, H.
    Lappeenranta University of Technology, Lahti, Finland.
    Gustafsson, Christine
    Mälardalens högskola, Akademin för hälsa, vård och välfärd, Hälsa och välfärd.
    Improved Knowledge Changes the Mindset: Older Adults’ Perceptions of Care Robots2019Inngår i: Lecture Notes in Computer Science, vol. 11592, Springer Verlag , 2019, s. 212-227Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper explores Finnish, German and Swedish older adults’ perceptions of a future welfare service with increased use of welfare technologies, specifically care robots. The issues are the rapid digitalization and development of health and welfare technology, which presently is mainly technology driven (not need or user driven), and the demographic challenge. The aim of the study was to explore older adults’ perception of the future use of welfare technology or care robots. A qualitative approach with focus group discussions was employed, followed by thematic analysis. The results are presented in four overall themes: the impact on daily life for older adults and professional caregivers, codes of practice and terms of use, dissemination of information and knowledge, and conditions for successful implementation. There were significant differences in the informants’ attitudes toward and knowledge about care robots. However, the informants’ attitudes appeared to change during the focus groups and in general, became more positive. Authentic needs, which care robots could support, refer to independence, safety and security, and the ability to manage or ease daily life or working life. The results suggest that older adults, after receiving relevant information, were open to the idea of being supported by care robots in their daily lives. 

  • 83.
    Jonsson, Annika
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Bergstrand, Sara
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Lindgren, Margareta
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Ek, Anna-Christina
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Lindén, Maria
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Blodflödesmätningar for att studera uppkomst uppkomst och förebyggande av trycksår2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Bakgrund: Trycksar ar ett alltjamt vanligt forekommande problem inom dagens sjukvard. Antalet personer i riskzonen att utveckla trycksar okar i takt med att vi blir allt aldre och sjukare samtidigt som allt mer allvarligt skadade personer idag kan raddas till livet. Den primara orsaken till trycksar ar ischemi men antalet sekundara faktorer ar stort. Den yttre belastningen av vavnaden som orsakar ischemi innefattar bade normal- och skjuvkrafter. Skjuvkrafter ar krafter som appliceras tangentiellt mot vavnaden och som leder till att kapillarernas diameter minskar och att blodflodet genom dem darmed minskar eller upphor.

    Idag ar det framforallt tryckmatningar av olika slag som anvands i forskning rorande trycksaretiologi. Tryckmatningar gors ocksa vid utvardering av de specialmadrasser som anvands for att forebygga och underlatta lakningen av redan uppkomna trycksar. Eftersom ar ischemi ar den primara orsaken till trycksar anser vi att blodflodet en mer direkt parameter att studera.

    Metod: Forandringar av blodflodet i sakrum vid yttre belastning har studerats i tva separata studier. I den forsta studien anvandes de tva vedertagna metoderna laser Doppler och fotopletysmografi. Genom olika kombinationer av vaglangd pa ljuset och avstand mellan ljuskalla och detektor kunde ett flertal olika matdjup erhallas. I den andra studien anvandes en Laser Doppler Flowmeter med tva kanaler for att studera forandringar av blodflodet vid anlaggande av skjuvkraft.

    Resultat: Vara studier har visat att bade normalkrafter och skjuvkrafter kan minska blodflodet i vavnaden. Det som visade sig speciellt intressant efter de forsta preliminara analyserna av resultaten fran studien med flera matdjup ar att blodflodet pa olika djup, det vill saga i de olika vavnadslagren, paverkas olika. Resultatet fran den andra studien visar att belastning av skjuvkrafter paverkar framfor allt det ytliga blodflodet negativt.

    Sammanfattning: Det ar viktigt att observera att det vid belastning av huden i princip ar omojligt att separera paverkan fran tryck respektive skjuvkrafter. Dock visar vara resultat att bade tryck och skjuvkrafter kan paverka blodflodet negativt. Vidareutveckling av metoden for blodflodesmatning mojliggor studier av hur blodflodet i ett storre vavnadsomrade paverkas av yttre belastning. Matningar i ett storre omrade bor kunna ge nya ron om etiologin bakom trycksar samt vara anvandbara vid utvardering av trycksarmadrasser.

  • 84. Klevbo, Louise
    et al.
    Jonsson, Annika
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Ford, Nerrolyn
    Peripheral circulatory response to shear stress applied to the sacral regionManuskript (Annet vitenskapelig)
  • 85.
    Koshmak, Gregory
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Loutfi, A.
    Örebro University, Örebro, Sweden.
    Fall risk probability estimation based on supervised feature learning using public fall datasets2016Inngår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, Vol. 2016, 2016, s. 752-755, artikkel-id 7590811Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Risk of falling is considered among major threats for elderly population and therefore started to play an important role in modern healthcare. With recent development of sensor technology, the number of studies dedicated to reliable fall detection system has increased drastically. However, there is still a lack of universal approach regarding the evaluation of developed algorithms. In the following study we make an attempt to find publicly available fall datasets and analyze similarities among them using supervised learning. After preforming similarity assessment based on multidimensional scaling we indicate the most representative feature vector corresponding to each specific dataset. This vector obtained from a real-life data is subsequently deployed to estimate fall risk probabilities for a statistical fall detection model. Finally, we conclude with some observations regarding the similarity assessment results and provide suggestions towards an efficient approach for evaluation of fall detection studies.

  • 86.
    Kristoffersson, Annica
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Örebro University, Sweden.
    Kolkowska, Ella
    Örebro University, Sweden.
    Loutfi, Amy
    Örebro University, Sweden.
    Summative evaluation of a sensor-based cognitive assistive technology: Impact on quality of life and perceived utility2019Inngår i: Gerontechnology, ISSN 1569-1101, E-ISSN 1569-111X, Vol. 18, nr 2, s. 59-69Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background Current research shows that perceived improvement of quality of life (QoL) is among the most important factors influencing acceptance of technology by older adults. Research Aim/question(s) The purpose of this study was to assess the utility of a sensor-based cognitive assistive technology (CAT) deployed in real homes and its impact on older adults’ and their informal caregivers’ perceived QoL. Methods During a period of five months, we conducted a summative evaluation by deploying a CAT in the home of couples in which one of the partners had a self-perceived memory decline. We applied a mixed method approach. Quantitative and qualitative data was collected via subjective forms, observations and 28 interviews conducted prior to the deployment, when the CAT was deployed and one month after the CAT removal. Results The study showed that the CAT had a psychosocial impact on older adults with a self-perceived memory decline and their informal caregivers but no impact on subjective forms measuring physiological and mental health, anxiety, depression or QoL. Additionally, we found that the CAT lacked a number of functionalities and that the test persons experienced several problems of different nature when using it in their homes. This affected the users’ experienced impact of the CAT. Conclusions This study contributes to the literature on sensor networks’ impact on QoL. While previous studies often use general forms intended to assess QoL, this summative evaluation indicates that using such instruments without considering contextual factors is not meaningful. The study also outlines a number of factors that sensor network providers might consider in order to increase their products impact on QoL and their perceived utility.

  • 87.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, JanMälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Developments in Near-Infrared Spectroscopy2017Collection/Antologi (Fagfellevurdert)
    Abstract [en]

    Over the past few decades, exciting developments have taken place in the field of near-infrared spectroscopy (NIRS). This has been enabled by the advent of robust Fourier transform interferometers and diode array solutions, coupled with complex chemometric methods that can easily be executed using modern microprocessors. The present edited volume intends to cover recent developments in NIRS and provide a broad perspective of some of the challenges that characterize the field. The volume comprises six chapters overall and covers several sectors. The target audience for this book includes engineers, practitioners, and researchers involved in NIRS system design and utilization in different applications. We believe that they will greatly benefit from the timely and accurate information provided in this work.

  • 88.
    Lindborg, Ann-Louise
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Development of an eating aid - From the user needs to a product2015Inngår i: Studies in Health Technology and Informatics, vol. 211, 2015, s. 191-198Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, the development process of an eating aid is described. The assistive devices must be worth using. To achieve this, the starting point has been the users need. The development started from the needs of an individual person, the inventor of the aid. The development has been about increasing the positive experience of the aid and decrease negative experience through an iterative development process. The development includes several evaluations, described in the paper, and as a conclusion, it is important to include the users throughout the development process. 

  • 89.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Embedded Sensor Systems for Health2018Inngår i: World Congress on Medical Physics and Biomedical Engineering IUPESM 2018, 2018, nr 1Konferansepaper (Fagfellevurdert)
  • 90.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Embedded sensor systems for health-providing the tools in future healthcare2014Inngår i: Stud. Health Technol. Informatics, 2014, s. 161-163Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Wearable, embedded sensor systems for health applications are foreseen to be enablers in the future healthcare. They will provide ubiquitous monitoring of multiple parameters without restricting the person to stay at home or in the hospital. By following trend changes in the health status, early deteriorations will be detected and treatment can start earlier. Also health prevention will be supported. Such future healthcare requires technology development, including miniaturized sensors, smart textiles and wireless communication. The tremendous amount of data generated by these systems calls for both signal processing and decision support to guarantee the quality of data and avoid overflow of information. Safe and secure communications have to protect the integrity of the persons monitored.

  • 91.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Inbyggda sensorsystem for hälsa – forskningsprofilen ESS-H2013Inngår i: Medicinteknikdagarna: Medicinteknikdagarna 2013, 2013Konferansepaper (Fagfellevurdert)
  • 92.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Inbyggda Sensorsystem för hälsa - teknik som stödjer trendmonitorering i hemmet2018Inngår i: Medicinteknikdagarna 2018 MTD 2018, Umeå, Sweden, 2018Konferansepaper (Fagfellevurdert)
  • 93.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Gerdtman, C.
    Motion Control AB, Västerås, Sweden.
    Hök, B.
    Hök Instrument AB, Västerås, Sweden.
    Embedded sensor systems for health – Collaboration between industry, academia and healthcare2017Inngår i: IFMBE Proceedings, Springer Verlag , 2017, s. 964-967Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Embedded Sensor Systems for Health (ESS-H) is a research profile at Mälardalen University (MDH) in Sweden, where researchers are working together with several industrial partners, and healthcare organizations. The aim of the research profile is to develop novel embedded sensor systems promoting health. The sensor systems are developed with the aim to monitor health conditions and follow health trends of elderly at home, and also for monitoring of drivers and machine operators in order to achieve a safer work environment. Several companies are involved in the work in various ways; providing specialist competence, providing equipment and access to advanced laboratory settings, and also working as adjunct professors and providing industrial PhD students to the environment. Healthcare providers are involved in the work, providing end-user perspective to the work. This includes to provide real user-driven challenges, and involvement in all development phases. © Springer Nature Singapore Pte Ltd. 2018.

  • 94.
    Lindén, Maria
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Kristoffersson, Annica
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Embedded Sensor Systems for Health Plus (ESS-H+) An overview of scientific areas and interdisciplinary target2019Inngår i: Abstractbok, 2019, s. 17-17Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    ESS-H+ will continue the work in the KKS research profile Embedded Sensor Systems for Health (ESS-H) at Mälardalen University. ESS-H has during six years provided important collaboration between researchers, industrial partners and healthcare organizations within three focus areas (Health monitoring at home, Health monitoring at work, and Infrastructure and communication).

    The focus of the new research profile ESS-H+ is that monitoring of humans should be able to be performed anytime, anywhere. Our research challenges are focused to the areas of Reliable acquisition and management of physiological data, and Reliable distributed data analysis. Reliable acquisition and management of physiological data is a fundamental prerequisite for advancing anytime, anywhere health monitoring, towards enabling remote monitoring of more serious health conditions than what is safely possible today. Reliable distributed data analysis is a fundamental prerequisite for enabling large-scale deployment of anytime, anywhere health monitoring. Both research challenges are complex and require multi-disciplinary research.

    The following important research goals will be addressed within ESS-H+: 

    • Reliable data acquisition, and design of suitable sensor systems for achieving this. 
    • Development of analysis and classification algorithms for physiological parameters. 
    • Achieve efficient distributed data fusion and decision support. 
    • Better utilization of the compute power of sensor nodes, and increased communication reliability: safety as well as security. 
    • Efficient integration of scientific results, from different scientific areas, to an efficient and user-friendly embedded sensor system. 

    The research in ESS-H+ will include research within the scientific areas (Biomedical sensor technology, Biomedical signal processing, Intelligent decision support, and Reliable and secure data communication) but also a strong integration between these areas, our collaborating companies, and the end users. Our main challenge within ESS-H+ will be this interdisciplinary integration that aims towards fully operating systems, thud providing efficient integration of scientific results, from different scientific areas, to an efficient and user-friendly embedded sensor system.

  • 95.
    Lindén, Maria
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Öberg, ÅkeMälardalens högskola, Institutionen för datavetenskap och elektronik.
    Jacobsons Medicin och Teknik2006Collection/Antologi (Annet vitenskapelig)
  • 96.
    Ljungblad, Jonas
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Hök Instrument AB, Sweden.
    Hök, Bertil
    Hök Instrument AB, Sweden.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Development and Evaluation of Algorithms for Breath Alcohol Screening2016Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, nr 4, artikkel-id 469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Breath alcohol screening is important for traffic safety, access control and other areas of health promotion. A family of sensor devices useful for these purposes is being developed and evaluated. This paper is focusing on algorithms for the determination of breath alcohol concentration in diluted breath samples using carbon dioxide to compensate for the dilution. The examined algorithms make use of signal averaging, weighting and personalization to reduce estimation errors. Evaluation has been performed by using data from a previously conducted human study. It is concluded that these features in combination will significantly reduce the random error compared to the signal averaging algorithm taken alone.

  • 97.
    Lum, KinYun
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Tan, T. S.
    Universiti Teknologi Malaysia, Malaysia.
    Impedance matching wireless power transmission system for biomedical devices2015Inngår i: Studies in Health Technology and Informatics, vol 211, 2015, s. 225-232Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For medical application, the efficiency and transmission distance of the wireless power transfer (WPT) are always the main concern. Research has been showing that the impedance matching is one of the critical factors for dealing with the problem. However, there is not much work performed taking both the source and load sides into consideration. Both sides matching is crucial in achieving an optimum overall performance, and the present work proposes a circuit model analysis for design and implementation. The proposed technique was validated against experiment and software simulation. Result was showing an improvement in transmission distance up to 6 times, and efficiency at this transmission distance had been improved up to 7 times as compared to the impedance mismatch system. The system had demonstrated a near-constant transfer efficiency for an operating range of 2cm-12cm. 

  • 98.
    Mansoor Baig, Mirza
    et al.
    Auckland University of Technology, Auckland, New Zealand.
    GholamHosseini, Hamid
    Auckland University of Technology, Auckland, New Zealand.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Connolly, Martin J
    University of Auckland, North Shore Hospital, Auckland, New Zealand .
    Review of Vital Signs Monitoring Systems - – Patient’´s Acceptability, Issues and Challenges2014Inngår i: Neuroscience and Biomedical Engineering, ISSN 2213-3852, Vol. 2, nr 1, s. 2-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vital signs are often considered as critical information to assess initial health condition and underlying health issues. Vital signs can contribute towards early detection, early diagnosis and risk reduction of fatal incidents. Today’s advanced monitoring systems incorporate the balanced combination of clinical and technological aspects to give an innovative healthcare outcome. Vital signs monitoring systems are rapidly becoming the core of today’s healthcare deliveries. The paradigm shifted from traditional and manual recording to computer based electronic records and further to smartphones as versatile and innovative healthcare monitoring systems. In this paper, the vital signs monitoring systems are classified as wearable, wireless and mobile monitoring systems and patient acceptability of some of these systems has been evaluated using 30 participants. Moreover, a comprehensive review of related literature in the context of acceptability, mobility, reliability and efficiency of vital signs monitoring systems in healthcare delivery and handling physiological measurements is presented. The outcome of this study indicates that despite some limitations commented by patients and clinicians, these systems should be more compact and simple to operate and they should be available to healthcare professionals with minimum interruption to normal daily life activities (ADLs).

  • 99.
    Martin, Lene
    et al.
    Mälardalens högskola, Akademin för hälsa, vård och välfärd.
    Wanger, Peter
    Computer-assisted evaluation of the results of high-pass resolution perimetry. A knowledge-based system1991Inngår i: Perimetry Update 1990/91: Proceedings of the IXth International Perimetric Society Meeting / [ed] Mills RP and Heijl A, Amsterdam/New York: Kugler Publications , 1991, s. 297-301Konferansepaper (Fagfellevurdert)
  • 100.
    Martin-Ruiz, Maria Louisa
    et al.
    Universidad Politecnica de Madrid, Spain.
    Valero, Miguel Angel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Universidad Politecnica de Madrid, Spain.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nunez-Nagy, Susana
    Universidad de Alcala, Alcala de Henares, Madrid, Spain.
    Gutierrez Garcia, Angeles
    Universidad Autonoma de Madrid, Spain.
    Foundations of a Smart Toy Development for the Early Detection of Motoric Impairments at Childhood2015Inngår i: International Journal of Pediatric Research, ISSN 2469-5769, Vol. 1, nr 3, s. 1-5Artikkel i tidsskrift (Fagfellevurdert)
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