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  • 1.
    Aare, Magnus
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Evaluation of head response to ballistic helmet impacts, using FEM2003Conference paper (Refereed)
  • 2.
    Aare, Magnus
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Halldin, Peter
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Proposed global injury thresholds for oblique helmet impacts2003Conference paper (Refereed)
  • 3.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Berndtsson, Andreas
    Abtahi, Shirin
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Development and preliminary evaluation of an Android based heart rate variability biofeedback system2014In: Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE, IEEE conference proceedings, 2014, 3382-3385 p.Conference paper (Refereed)
    Abstract [en]

    The reduced Heart Rate Variability (HRV) is believed to be associated with several diseases such as congestive heart failure, diabetes and chronic kidney diseases (CKD). In these cases, HRV biofeedback may be a potential intervention method to increase HRV which in turn is beneficial to these patients. In this work, a real-time Android biofeedback application based on a Bluetooth enabled ECG and thoracic electrical bioimpedance (respiration) measurement device has been developed. The system performance and usability have been evaluated in a brief study with eight healthy volunteers. The result demonstrates real-time performance of system and positive effects of biofeedback training session by increased HRV and reduced heart rate. Further development of the application and training protocol is ongoing to investigate duration of training session to find an optimum length and interval of biofeedback sessions to use in potential interventions.

  • 4.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Ji, Guangchao
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rodby, Kristian
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    A knitted garment using intarsia technique for Heart Rate Variability biofeedback: Evaluation of initial prototype2015In: Engineering in Medicine and Biology Society (EMBC), 2015 37th Annual International Conference of the IEEE, IEEE , 2015, Vol. 2015, 3121-3124 p.Conference paper (Refereed)
    Abstract [en]

    Heart rate variability (HRV) biofeedback is a method based on paced breathing at specific rate called resonance frequency by giving online feedbacks from user respiration and its effect on HRV. Since the HRV is also influence by different factors like stress and emotions, stress related to an unfamiliar measurement device, cables and skin electrodes may cover the underling effect of such kind of intervention. Wearable systems are usually considered as intuitive solutions which are more familiar to the end-user and can help to improve usability and hence reducing the stress. In this work, a prototype of a knitted garment using intarsia technique is developed and evaluated. Results show the satisfactory level of quality for Electrocardiogram and thoracic electrical bioimpedance i.e. for respiration monitoring as a part of HRV biofeedback system. Using intarsia technique and conductive yarn for making the connection instead of cables will reduce the complexity of fabrication in textile production and hence reduce the final costs in a final commercial product. Further development of garment and Android application is ongoing and usability and efficiency of final prototype will be evaluated in detail.

  • 5.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Aslamy, Benjamin
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Boujabir, Imaneh
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    An Affordable ECG and Respiration Monitoring System Based on Raspberry PI and ADAS1000: First Step towards Homecare Applications2015In: 16th Nordic-Baltic Conference on Biomedical Engineering: 16. NBC & 10. MTD 2014 joint conferences. October 14-16, 2014, Gothenburg, Sweden, Springer, 2015, 5-8 p.Conference paper (Refereed)
    Abstract [en]

    Homecare is a potential solution for problems associated with an aging population. This may involve several physiological measurements, and hence a flexible but affordable measurement device is needed. In this work, we have designed an ADAS1000-based four-lead electrocardiogram (ECG) and respiration monitoring system. It has been implemented using Raspberry PI as a platform for homecare applications. ADuM chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 and IEC 60950 for patient safety. The result proved the potential of Raspberry PI for the design of a compact, affordable, and medically safe measurement device. Further work involves developing a more flexible software for collecting measurements from different devices (measuring, e.g., blood pressure, weight, impedance spectroscopy, blood glucose) through Bluetooth or user input and integrating them into a cloud-based homecare system.

  • 6.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Löfgren, Nils
    Elimination of ECG Artefacts in Foetal EEG Using Ensemble Average Subtraction and Wavelet Denoising Methods: A Simulation2014In: XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013, Springer, 2014, 551-554 p.Conference paper (Refereed)
    Abstract [en]

    Biological signals recorded from surface electrodes contain interference from other signals which are not desired and should be considered as noise. Heart activity is especially present in EEG and EMG recordings as a noise. In this work, two ECG elimination methods are implemented; ensemble average subtraction (EAS) and wavelet denoising methods. Comparison of these methods has been done by use of simulated signals achieved by adding ECG to neonates EEG. The result shows successful elimination of ECG artifacts by using both methods. In general EAS method which remove estimate of all ECG components from signal is more trustable but it is also harder for implementation due to sensitivity to noise. It is also concluded that EAS behaves like a high-pass filter while wavelet denoising method acts as low-pass filter and hence the choice of one method depends on application.

  • 7.
    Akay, Altug
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Dragomir, A.
    Erlandsson, Björn-Erik
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    A novel data-mining platform leveraging social media to monitor outcomes of Januvia2013In: Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE, IEEE conference proceedings, 2013, 7484-7487 p.Conference paper (Refereed)
    Abstract [en]

    A novel data-mining method was developed to gauge the experiences of the diabetes mellitus drug Januvia. Self-organizing maps were used to analyze forum posts numerically to infer user opinion of drug Januvia. Graph theory was used to discover influential users. The result is a word list compilation correlating positive and negative word cluster groups and a web of influential users on Januvia. The implications could open new research avenues into rapid data collection, feedback, and analysis that would enable improved solutions for public health.

  • 8.
    Almén, Lena
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Design Measures for Construction Site Safety2012In: The Conference of the Nordic Ergonomics Society, 2012Conference paper (Refereed)
    Abstract [en]

    Abstract:Since the 1st of January 2009, all Clients in Sweden are required to appoint a Health and Safety Coordinator for the design and planning phase of their building projects. Telephone interviews were carried out with the Coordinators of 42 building projects during 2010. They were asked to give examples of occupational hazards in the projects and to report how these were handled in the design and planning phase. Trauma risks as well as MSD-risks were identified in the design and planning phase. The hazards were mostly generally described and seldomly taken care of by design changes.

  • 9.
    Almén, Lena
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Larsson, Tore J.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    The Health and Safety Coordinators´Potential to Prevent Injuries on Construction Sites2012In: Working on Safety, 2012Conference paper (Refereed)
    Abstract [en]

    The risk of occupational disease and serious injury in the building and construction industry is high. The earlier in the construction process, the greater are the possibilities to reduce hazards.

    According to the Swedish legislation, Architects and Design Engineers shall, within the framework of their assignment, ensure that aspects of health and safety are considered during the construction of a building as well as in the use of the finished building.

    Since the 1st of January 2009, Clients (natural or legal persons for whom projects are carried out) in Sweden are obliged to appoint a Health and Safety Coordinator for the design and planning of the building. The Coordinators must have the educational skills and experience needed to perform their duties.

    The aim of this study was to find out what persons are appointed to be coordinators, how they perceive their duties and, potentially, what could facilitate the Health and Safety Coordinators’ activities and construction site safety.

    Telephone interviews were carried out with 40 Health and Safety Coordinators for the design and planning phase of 42 building projects during 2010.

    The Coordinators education and experiences varied to a large degree. Their description of duties also varied greatly, from no duties, to administrative duties, to active injury prevention.

    According to the Coordinators, the following factors had a positive influence on their possibilities to act for injury prevention:

    • The Coordinator is appointed early in the process
    • The Coordinator has authority in the project
    • The Client prioritizes occupational safety
    • There is knowledge of construction methods in the design team
  • 10.
    Alsmo, Thomas
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Causes of Poor Air Quality in Swedish Schools2006Conference paper (Refereed)
    Abstract [en]

    This literature survey distinguishes between building and other factors influencing air quality. It does not identify building factors sufficient to account for occupant complaints. It concludes that buildings are often blamed for adverse health effects without sufficient grounds. The risk is there will be too much focusing on the wrong underlying problem when remedying so-called sick buildings. The study shows the importance of ensuring that factors independent of the school building, including the choices of environments and activities, are important for the indoor environment.

  • 11.
    Alvarez, Victor S
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering.
    Importance of Windscreen Modelling Approach for Head Injury Prediction2016In: 2016 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 2016Conference paper (Refereed)
    Abstract [en]

    The objective of this study is to evaluate the capability of two modelling approaches in capturing  both accelerations and deformations from head impacts, and to evaluate the effect of modelling approach on  brain injury prediction. The first approach is a so‐called smeared technique, in which the properties of the two  glass  sheets and  the intermediate  polyvinyl  butyral  (PVB) are  combined and  divided into  two  coinciding  shell layers, of which one can fracture. The second approach consists of three shell layers, representing the glass and  PVB,  separated by  the  distance of  their  thickness, using a non‐local  failure criterion  to initiate  fracture in  the  glass.  The  two  modelling  approaches  are  compared  to  impact  experiments  of  flat  circular  windscreens,  measuring  deformations  and  accelerations  as  well  as  accelerations  from  impacts  against  full  vehicle  windscreens.  They  are  also  used  to  study  head‐to‐windscreen  impacts  using  a  detailed  Finite  Element  (FE)  model,  varying  velocity,  impact  direction  and  impact  point.  Only  the  non‐local  failure  model  is  able  to  adequately  capture  both  the accelerations and  deformations  of an  impactor. The FE  head model  simulations  also reveal that the choice of modelling approach has a large effect on the both localisation of the strain in the  brain and the characteristics of the strain‐time curve, with a difference in peak strain between 8% and 40%.  

  • 12.
    Andersson, Karin
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Work environment, Lean and Agriculture2014In: PROCEEDINGS: 11th International Symposium on Human Factors in Organisational Design and Management & 46th Annual Nordic Ergonomics Society Conference: Volume I + II, IEA Press , 2014, 661-666 p.Conference paper (Refereed)
    Abstract [en]

    Lean has become the predominant management concept in industry, but its effect on the work environment is debated. Lean has now reached farms and garden nurseries. This paper aims to identify consequences for the physical and psychosocial work environment when Lean was applied in micro-businesses in the agricultural sector. Observations, a questionnaire and interviews were used as methods. It was concluded that the psychosocial work environment became more structured and less stressful. The physical work environment was partly improved by less transportation on the farm. However, consideration of the physical work environment was insufficient.

  • 13. Andersson, Per
    et al.
    Björkholm, Peter
    Haasl, Sjoerd
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Johannisson, Pontus
    Johnsson, Christer
    Stigwall, Johan
    Södermalm, Svante
    MEMS-based inertial navigation instrumentation for high-dynamic applications2009In: COMS 2009, 2009Conference paper (Refereed)
  • 14.
    Asplund, Maria
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Hamedi, Mahiar
    Inganäs, Olle
    Forchheimer, Robert
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Neural microcontacts with wire electrodes and woven logic2007Conference paper (Refereed)
  • 15.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Buendia, Ruben
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Cole Function and Conductance-Based Parasitic Capacitance Compensation for Cerebral Electrical Bioimpedance Measurements2012In: Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE, San Diego: IEEE press , 2012, 3368-3371 p.Conference paper (Refereed)
    Abstract [en]

    One of the most common measurement artifacts present in Electrical Bioimpedance Spectroscopy measurements (EBIS) comes from the capacitive leakage effect resulting from parasitic stray capacitances. This artifact produces a deviation in the measured impedance spectrum that is most noticeable at higher frequencies. The artifact taints the spectroscopy measurement increasing the difficulty of producing reliable EBIS measurements at high frequencies. In this work, an approach for removing such capacitive influence from the spectral measurement is presented making use of a novel method to estimate the value of the parasitic capacitance equivalent that causes the measurement artifact. The proposed method has been tested and validated theoretically and experimentally and it gives a more accurate estimation of the value of the parasitic capacitance than the previous methods. Once a reliable value of parasitic capacitance has been estimated the capacitive influence can be easily compensated in the EBIS measured data. Thus enabling analysis of EBIS data at higher frequencies, i.e. in the range of 300-500 kHz like measurements intended for cerebral monitoring, where the characteristic frequency is remarkably higher than EBIS measurements i.e. within the range 30 to 50 kHz, intended for body composition assessment.

  • 16.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Electrical Bioimpedance cerebral monitoring. Preliminary results from measurements on stroke patients2012In: Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE, IEEE , 2012, 126-129 p.Conference paper (Refereed)
    Abstract [en]

    Electrical Bioimpedance Spectroscopy (EBIS) is currently used in different tissue characterization applications. In this work we aim to use EBIS to study changes in electrical properties of the cerebral tissues after an incident of hemorrhage/ischemic stroke. To do so a case-control study was conducted using six controls and three stroke cases. The preliminary results of this study show that by using Cole-based analysis on EBIS measurements and analyzing the Cole parameters R0 and R∞, it is possible to detect changes on electrical properties of cerebral tissue after stroke. 

  • 17.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Study of the dynamics of transcephalic cerebral impedance data during cardio-vascular surgery2013In: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT), Institute of Physics (IOP), 2013, Vol. 434, no 1, 012045- p.Conference paper (Refereed)
    Abstract [en]

    Postoperative neurological deficits are one of the risks associated with cardio vascular surgery, necessitating development of new techniques for cerebral monitoring. In this study an experimental observation regarding the dynamics of transcephalic Electrical Bioimpedance (EBI) in patients undergoing cardiac surgery with and without extracorporeal circulation (ECC) was conducted to investigate the potential use of electrical Bioimpedance for cerebral monitoring in cardio vascular surgery. Tetrapolar transcephalic EBI measurements at single frequency of 50 kHz were recorded prior to and during cardio vascular surgery. The obtained results show that the transcephalic impedance decreases in both groups of patients as operation starts, however slight differences in these two groups were also observed with the cerebral impedance reduction in patients having no ECC being less common and not as pronounced as in the ECC group. Changes in the cerebral impedance were in agreement with changes of haematocrit and temperature. The origin of EBI changes is still unexplained however these results encourage us to continue investigating the application of electrical bioimpedance cerebral monitoring clinically.

  • 18.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Ishihara, Shigekazu
    An Analysis on Affective Design of Servicescapes2009In: Proceedings of 12 th QMOD and Toulon-Verona Conference on Quality and Service Sciences, 2009Conference paper (Refereed)
  • 19.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Jörgen, Eklund
    KTH, School of Technology and Health (STH), Ergonomics.
    Identifying trigger feeling factors2010In: International Conference on Kansei Engineeringand Emotional Research (KEER), Paris, France, 2010Conference paper (Refereed)
    Abstract [en]

    Trigger mechanism design in power hand tools is of great importance for communicating with the operator and for providing feedback on operational functioning. Therefore, for a successful power hand tool design, knowledge about how the trigger mechanism feels is required.

    This study aims to define and investigate the design factors related with trigger tactile feeling for electrical right angled nutrunners. A Kansei Engineering (Affective Engineering) study has been conducted for a comparison between users´ (operators that work at an automotive assembly plant) and product developers´ (product development group of a power hand tool manufacturer) to find common and differing semantic expression dimensions for that. 124 Kansei words (descriptors) were collected from literature, interviews and workshops. These words were reduced to 52 by affinity analysis and evaluated by operators and product developers using semantic differential technique.

    From the operator group`s responses six factors (explain 87% of variation ) were extracted as, “professional performance”, “safety and tactile feeling”, “usability”, “smooth operation”, ”communication and durability”, “convenient and comfortable” to define trigger feeling. Correspondingly, five factors (explain 89% of variation) “robust and appealing”, “ergonomics and operator performance”, “controllability and predictability”, “creativity and modern” and“powerful” were distinguished for the product development group. Results showed that the start phase and especially quick start of trigger mechanism is more important to operators, while end feedback is more important to product developers. Soft start of the trigger is correlated with ergonomics, optimal, clear operation and performance for product developers while soft start together with end feedback are associated with well-built, convenient and safe trigger characteristics for operators. According to the results from average ratings the Kansei word “ergonomic” has been rated as the most important descriptor for trigger feeling together with “user-friendly”, “easy to use”, “long life time” and “comfortable” for both groups. By developing a questionnaire using the factors and variables identified; this questionnaire can be used to assess views of operators about trigger functioning and to know how do operators feel about new types of trigger mechanisms.

  • 20. Aydoǧan, R.
    et al.
    Lo, J. C.
    Meijer, Sebastian A.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Health Care Logistics.
    Jonker, C. M.
    Modeling network controller decisions based upon situation awareness through agent-based negotiation2014In: 44th International Simulation and Gaming Association Conference, ISAGA 2013 and 17th IFIP WG 5.7 Workshop on Experimental Interactive Learning in Industrial Management, Springer-Verlag Tokyo Inc., 2014, 191-200 p.Conference paper (Refereed)
    Abstract [en]

    The Dutch railway traffic control is in an urgent need for innovation and therefore turns to gaming simulation as a platform to test and train future configurations of the system. The presence of relevant participants is necessary to keep the fidelity of the gaming simulation high. Network controllers are often needed in such games, but are expensive, scarce, and often have limited action, thus making their involvement less than desirable. To overcome this, the current paper introduces the use of intelligent software agents to replace some roles. The cognitive construct of situation awareness is required to model the evaluation of an offer in a negotiation setting, in which a situation awareness model (SAM) is introduced for evaluating offers in complex and dynamic systems.

  • 21.
    Ayllon, David
    et al.
    Department of Signal Theory and Communications.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Gil-Pita, Roberto
    Department of Signal Theory and Communications.
    Cole equation and parameter estimation from electrical bioimpedance spectroscopy measurements: A comparative study2009In: EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20, Buenos Aires: IEEE Engineering in Medicine and Biology , 2009, 3779-3782 p.Conference paper (Refereed)
    Abstract [en]

    Since there are several applications of Electrical Bioimpedance (EBI) that use the Cole parameters as base of the analysis, to fit EBI measured data onto the Cole equation is a very common practice within Multifrequency-EBI and spectroscopy. The aim of this paper is to compare different fitting methods for EBI data in order to evaluate their suitability to fit the Cole equation and estimate the Cole parameters. Three of the studied fittings are based on the use of Non-Linear Least Squares on the Cole model, one using the real part only, a second using the imaginary part and the third using the complex impedance. Furthermore, a novel fitting method done on the impedance plane, without using any frequency information has been implemented and included in the comparison. Results show that the four methods perform relatively well but the best fitting in terms of standard error of estimate is the fitting obtained from the resistance only. The results support the possibility of measuring only the resistive part of the bioimpedance to accurately fit Cole equation and estimate the Cole parameters, with entailed advantages.

  • 22. Azar, J.C.
    et al.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Medical Engineering.
    Automated Tracking of the Carotid Artery in Ultrasound Image Sequences Using a Self Organizing Neural Network2010In: Proceedings of 20th International Conference on Pattern Recognition (ICPR 2010), Istanbul, Turkey, Istanbul, Turkey, 2010, 2548-2551 p.Conference paper (Refereed)
    Abstract [en]

    An automated method for the segmentation and tracking of moving vessel walls in 2D ultrasound image sequences is introduced. The method was tested on simulated and real ultrasound image sequences of the carotid artery. Tracking was achieved via a self organizing neural network known as Growing Neural Gas. This topology-preserving algorithm assigns a net of nodes connected by edges that distributes itself within the vessel walls and adapts to changes in topology with time. The movement of the nodes was analyzed to uncover the dynamics of the vessel wall. By this way, radial and longitudinal strain and strain rates have been estimated. Finally, wave intensity signals were computed from these measurements. The method proposed improves upon wave intensity wall analysis, WIWA, and opens up a possibility for easy and efficient analysis and diagnosis of vascular disease through noninvasive ultrasonic examination.

  • 23.
    Azhari, Mohammad
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Health Care Logistics.
    Raghothama, Jayanth
    KTH, School of Technology and Health (STH), Health Systems Engineering, Health Care Logistics.
    Meijer, Sebastiaan
    KTH, School of Technology and Health (STH), Health Systems Engineering, Health Care Logistics.
    A Design and Implementation of Interactive Visualizations and Simulation in Transportation2014In: The Shift from Teaching to Learning: Individual, Collective and Organizational Learning Through Gaming Simulation: Proceedings of the 45th Conferenceof the International Simulation and Gaming Association, 2014Conference paper (Refereed)
    Abstract [en]

    Transportation Planners have a long history of using Geographical Information Systems, Simulation Models and Visualizations for decision support. A frame-work that integrates all three can provide enhanced decision support, opportuni-ties for training and planning future scenarios. In the current paper, we describe the concept of such a framework and the first steps toward its development.

  • 24.
    Baltoglou, Georgios
    et al.
    KTH, School of Technology and Health (STH).
    Karapistoli, E.
    Chatzimisios, P.
    IPTV QoS and QoE measurements in wired and wireless networks2012In: 2012 IEEE Global Communications Conference (GLOBECOM), IEEE , 2012, 1757-1762 p.Conference paper (Refereed)
    Abstract [en]

    Internet Protocol Television or IPTV is a multimedia content delivery service that is increasingly proliferating in the consumers lives and a hot-topic for telecommunication companies to gain a share on consumers' entertainment budget. This alternate method of distributing television content over IP requires a high level of network performance and guaranteed Quality of Service (QoS) in order for the end user to have an assured and high-quality viewing experience. Yet, the quality margins of IPTV are commonly put to test in almost all cases where customers re-distribute the service within their premisses. In this paper, our main motivation is to investigate how such real-life networks perform in terms of distributing this inelastic and high-bandwidth type of service utilizing traffic measurements. Furthermore, our goal is to verify and analyze whether these studied networks are well suited for multicast IPTV traffic.

  • 25.
    Baltoglou, Georgios
    et al.
    KTH, School of Technology and Health (STH).
    Karapistoli, Eirini
    Chatzimisios, Periklis
    Real-World IPTV Network Measurements2011In: 2011 IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATIONS (ISCC), 2011Conference paper (Refereed)
    Abstract [en]

    Internet Protocol Television or IPTV is defined as an alternate method of distributing television content over IP by a telecom carrier or an Internet service provider (ISP) and it is increasingly gaining market share in modern communication networks. IPTV poses specific requirements on the network infrastructure and at the same time it requires that several network performance characteristics are maintained under defined levels in order for the end user to have an assured viewing experience. In this paper, our main motivation is to investigate how a real life network performs in terms of distributing this inelastic and high-bandwidth type of service utilizing traffic measurements. Furthermore, our goal is to verify and analyze whether the studied network is suited for multicast IPTV traffic.

  • 26.
    Batool, Nazre
    KTH, School of Technology and Health (STH).
    Detection and Spatial Analysis of Hepatic Steatosis in Histopathology Images using Sparse Linear Models2016In: 2016 SIXTH INTERNATIONAL CONFERENCE ON IMAGE PROCESSING THEORY, TOOLS AND APPLICATIONS (IPTA), IEEE, 2016Conference paper (Refereed)
    Abstract [en]

    Hepatic steatosis is a defining feature of nonalcoholic fatty liver disease, emerging with the increasing incidence of obesity and metabolic syndrome. The research in image-based analysis of hepatic steatosis mostly focuses on the quantification of fat in biopsy images. This work furthers the image-based analysis of hepatic steatosis by exploring the spatial characteristics of fat globules in whole slide biopsy images after performing fat detection. An algorithm based on morphological filtering and sparse linear models is presented for fat detection. Then the spatial properties of detected fat globules in relation to the hepatic anatomical structures of central veins and portal tracts are explored. The test dataset consists of 38 high resolution images from 21 patients. The experimental results provide an insight into the size distributions of fat globules and their location with respect to the anatomical structures.

  • 27. Beillas, P.
    et al.
    Petit, P.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering.
    Kirscht, S.
    Chawla, A.
    Jolivet, E.
    Faure, F.
    Praxl, N.
    Bhaskar, A.
    Specifications of a software framework to position and personalise human body models2015In: 2015 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, International Research Council on the Biomechanics of Injury , 2015, 594-595 p.Conference paper (Refereed)
  • 28.
    Bergholm, Fredrik
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsolle, A.
    Acquiring instantaneous multispectral imagery using a single image sensor with multiple filter mosaic2007Conference paper (Other academic)
  • 29.
    Berglund, Martina
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Karltun, Johan
    Högskolan i Jönköping, JTH.
    Schedulers’ work content – a quantified analysis2006Conference paper (Refereed)
  • 30. Bora, K.
    et al.
    Chowdhury, Manish
    KTH, School of Technology and Health (STH).
    Mahanta, L. B.
    Kundu, M. K.
    Das, A. K.
    Pap smear image classification using convolutional neural network2016In: ACM International Conference Proceeding Series, Association for Computing Machinery , 2016Conference paper (Refereed)
    Abstract [en]

    This article presents the result of a comprehensive study on deep learning based Computer Aided Diagnostic techniques for classification of cervical dysplasia using Pap smear images. All the experiments are performed on a real indigenous image database containing 1611 images, generated at two diagnostic centres. Focus is given on constructing an effective feature vector which can perform multiple level of representation of the features hidden in a Pap smear image. For this purpose Deep Convolutional Neural Network is used, followed by feature selection using an unsupervised technique with Maximal Information Compression Index as similarity measure. Finally performance of two classifiers namely Least Square Support Vector Machine (LSSVM) and Softmax Regression are monitored and classifier selection is performed based on five measures along with five fold cross validation technique. Output classes reflects the established Bethesda system of classification for identifying pre-cancerous and cancerous lesion of cervix. The proposed system is also compared with two existing conventional systems and also tested on a publicly available database. Experimental results and comparison shows that proposed system performs efficiently in Pap smear classification.

  • 31.
    Brenning, Magnus
    et al.
    KTH, School of Technology and Health (STH).
    Olander, Björn
    KTH, School of Technology and Health (STH).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering.
    Vennberg, Johan
    KTH, School of Technology and Health (STH).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering. 2Laboratory for communication networks, School of Electrical Engineering, KTH.
    NeTraWeb - A Web-Based Traffic Flow Performance Meter2006In: 4th Swedish National Computer Networking Workshop SNCNW 2006, 2006Conference paper (Refereed)
    Abstract [en]

    This paper presents a web-based traffic flow performance meter. The NeTraWeb tool configures and automates the measurement activities, including storage and presentation of the main performance parameters.

  • 32. Broomé, Michael
    et al.
    Maksuti, Elira
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Waldenström, Anders
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Simulation of arterial hypertension and progressive arteriosclerosis with a 0-D multipurpose cardiovascular model2013In: CMBE13: 3rd International Conference on Computational & Mathematical Biomedical Engineering, 2013, 433-436 p.Conference paper (Refereed)
    Abstract [en]

    The effects of systemic vascular resistance and progressive stiffening/arteriosclerosis inthe vascular tree on arterial blood pressure is explored in a 0D cardiovascular simulationmodel. Pulse pressure is both sensitive and specific for increases in stiffness and meanarterial pressure both sensitive and specific for changes in vascular resistance.

  • 33. Brown, Shannon
    et al.
    Ortiz-Catalan, Max
    Petersson, Joel
    Rodby, Kristian
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering. University of Borås, Sweden.
    Intarsia-Sensorized Band and Textrodes for Real-Time Myoelectric Pattern Recognition2016In: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS / [ed] Patton, J Barbieri, R Ji, J Jabbari, E Dokos, S Mukkamala, R Guiraud, D Jovanov, E Dhaher, Y Panescu, D Vangils, M Wheeler, B Dhawan, AP, Institute of Electrical and Electronics Engineers (IEEE), 2016, 6074-6077 p., 7592114Conference paper (Refereed)
    Abstract [en]

    Surface Electromyography (sEMG) has applications in prosthetics, diagnostics and neuromuscular rehabilitation. Self-adhesive Ag/AgCl are the electrodes preferentially used to capture sEMG in short-term studies, however their long-term application is limited. In this study we designed and evaluated a fully integrated smart textile band with electrical connecting tracks knitted with intarsia techniques and knitted textile electrodes. Real-time myoelectric pattern recognition for motor volition and signal-to-noise ratio (SNR) were used to compare its sensing performance versus the conventional Ag-AgCl electrodes. After a comprehending measurement and performance comparison of the sEMG recordings, no significant differences were found between the textile and the Ag-AgCl electrodes in SNR and prediction accuracy obtained from pattern recognition classifiers.

  • 34.
    Brown, Shannon
    et al.
    Högskolan i Borås.
    Ortiz-Catalan, Max
    Chalmers University of Technology.
    Petersson, Joel
    Högskolan i Borås.
    Rödby, Kristian
    Högskolan i Borås.
    Seoane, Fernando
    KTH, School of Technology and Health (STH). Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Intarsia-sensorized band and textrodes for real-time myoelectric pattern recognition2016In: Engineering in Medicine and Biology Society (EMBC), 2016 IEEE 38th Annual International Conference of the, Institute of Electrical and Electronics Engineers (IEEE), 2016, 6074-6077 p.Conference paper (Refereed)
  • 35.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Lean administration: En litteraturgenomgång av lean när konceptet implementeras i kommuner2011In: FALF2011: Det nya arbetslivet, Luleå: FALF , 2011Conference paper (Refereed)
    Abstract [sv]

    Lean blir allt vanligare i svensk offentlig förvaltning. Litteraturstudier har tidigare genomförts inom sjukvård och service. Denna litteraturgenomgång fokuserar istället på kommuner. Fokus ligger på vilka former som lean-konceptet tar, hur det implementeras, vilka effekter som uppnås, samt vilka svårigheter som man stött på. Sökningar gjordes i två omgångar i fyra olika databaser under i maj 2010. Endast empiriska artiklar i peer-reviewadetidsskrifter inkluderades; studier som inom vård- eller industriliknande kontexterexkluderades. Totalt resulterade sökningen och urvalsprocessen i fem publikationer, som beskriver lean i elva verksamheter. Slutsatserna från genomgången av dessa är de studerade lean-implementeringar i hög grad utgår från en ansats som påminner om värdeflödeskartläggningar. Fokus för lean-arbetet ligger på verktyg och system för förbättringsarbete. De upplevda problemen i lean-arbetet är framför allt associerade med implementeringsansatsen, snarare än konceptet eller kontexten. Verksamheternas arbete med lean har gett mestadels positiva verksamhetseffekter, framför allt rörande effektivitet och produktivitet. Hur kunderna, och framför allt personalen, påverkats är dock osäkrare.

  • 36.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Lean Working Environments: An Empirical Study of 24 CompaniesImplementing Lean2010In: NES2010: Proactive Ergonomics: Implementation of ergonomics in planning of jobs, tasks, systems and environments., Stavanger, 2010Conference paper (Refereed)
    Abstract [en]

    This paper studies the perceived effects on the working conditions in 24 medium sized manufacturing companies, approximately 1.5 year into their implementation of Lean. This is studied quantitatively based on four stakeholders’ perceptions (the workers, the managers, the production supervisors and the white-collar workers), based on three factors; changes in the working environment, work with safety for the personnel and level of stress. The results indicate that the physical work environments have improved and the workers and production supervisors report a slight increase in stress. Lastly, all groups report an increase in the work with safety for the personnel.

  • 37.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Halvarsson, Agneta
    Linköpings universitet, HELIX VINN Excellence Centre.
    Lindskog, Pernilla
    KTH, School of Technology and Health (STH), Ergonomics.
    Implementing Lean in Swedish Municipalities and Hospitals: Initial effects on the work system2011In: FALF2011:Det nya arbetslivet, Luleå: FALF , 2011Conference paper (Refereed)
    Abstract [en]

    This paper is the first preliminary product of a three year interactive research project, studying the effects of Lean when introduced in Swedish municipalities and hospitals. Focus of the paper is the implementation process (more specifically, employee participationand facilitated learning) and changes in the work system (focusing on work content, organization and work environment). The empirical data has been collected through interviews and group interviews in three municipalities and one hospital. These results, together with the discussion and analysis, shows firstly that the implementation processes of the studied units are characterized by a medium or high level of opportunities for employee participation and learning, although this is produced in different ways. Second, the changes in the work systems mostly affect the organization of the work, through reorganization and redistribution of the work tasks, rather than changes in how the work tasks are performed.This has lead to more orderly and structured work processes. Lastly, the employees’ reactions to these changes have been mostly positive, although not exclusively so. However, it is important to stress that the employee reactions are most likely as much a result of the implementation process, as of the changes in the work systems. Longitudinal studies are therefore needed to study the long term changes in the work system and the effects on employee health, which will be the next step of this research project.

  • 38.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Lindskog, Pernilla
    KTH, School of Technology and Health (STH), Ergonomics.
    Halvarsson, Agneta
    Linköpings universitet, HELIX VINN Excellence Centre.
    Patient Quality Effects from Lean Healthcare: An Empirical Investigation2012In: NES2012 Proceedings.: Ergonomics for sustainability and growth / [ed] Ann-Beth Antonsson, Göran Hägg, Stockholm: KTH Royal Institute of Technology, 2012Conference paper (Refereed)
    Abstract [en]

    The use of Lean in healthcare settings has become common in Swedish hospitals. However, the effects from Lean on patients have not been studied extensively. This paper contributes to our understanding of this question, based on 24 semi-structured interviews in three municipal care units and three units in hospitals. The results indicate that there may be a positive link between Lean activities and quality of care. However, it is plausibly a weak link, heavily modulated by non-Lean factors. Thus, we need more empirical research to understand the causal link between patient safety and quality of care from Lean Healthcare.

  • 39.
    Buendia, Ruben
    et al.
    School of Engineering, University of Borås.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Cole parameter estimation from total right side electrical bioimpedance spectroscopy measurements: Influence of the number of frequencies and the upper limit2011In: 2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), 2011, 1843-1846 p.Conference paper (Refereed)
    Abstract [en]

    Applications based on measurements of Electrical Bioimpedance Spectroscopy (EBIS) analysis are proliferating. The most spread and known application of EBIS is the non-invasive assessment of body composition. Fitting to the Cole function to obtain the Cole parameters, R<sub>0</sub> and R<sub>&#x221E;</sub>, is the core of the EBIS analysis to obtain the body fluid distribution. An accurate estimation of the Cole parameters is essential for the Body Composition Assessment (BCA) and the estimation process depends on several factors. One of them is the upper frequency limit used for the estimation and the other is the number of measured frequencies in the measurement frequency range. Both of them impose requirements on the measurement hardware, influencing largely in the complexity of the bioimpedance spectrometer. In this work an analysis of the error obtained when estimating the Cole parameters with several frequency ranges and different number of frequencies has been performed. The study has been done on synthetic EBIS data obtained from experimental Total Right Side (TRS) measurements. The results suggest that accurate estimations of R<sub>0</sub> and R<sub>&#x221E;</sub> for BCA measurements can be achieved using much narrower frequency ranges and quite fewer frequencies than electrical bioimpedance spectrometers commercially available nowadays do.

  • 40.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Harris, Matthew
    Phillips Research.
    Caffarel, Jeniffer
    Phillips Research.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Hook Effect correction & resistance-based Cole fitting prior Cole model-based analysis: Experimental validation2010In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2010, IEEE Engineering in Medicine and Biology , 2010, 6563-6566 p.Conference paper (Refereed)
    Abstract [en]

    The analysis of measurements of Electrical Bioimpedance (EBI) is on the increase for performing non-invasive assessment of health status and monitoring of pathophysiological mechanisms. EBI measurements might contain measurements artefacts that must be carefully removed prior to any further analysis. Cole model-based analysis is often selected when analysing EBI data and might lead to miss-conclusion if it is applied on data contaminated with measurement artefacts. The recently proposed Correction Function to eliminate the influence of the Hook Effect from EBI data and the fitting to the real part of the Cole model to extract the Cole parameters have been validated on experimental measurements. The obtained results confirm the feasible experimental use of these promising pre-processing tools that might improve the outcome of EBI applications using Cole model-based analysis.

  • 41.
    Burmeister, Jens
    et al.
    University of Dresden, Germany.
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lundberg, Stefan
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Contention-Based Wireless Sensor Networks: A case study for ambient assisted living2010In: Active Ageing, Smart Solutions, New Markets, 2010Conference paper (Refereed)
    Abstract [en]

    Wireless personal area networks have emerged as an important communication infrastructure in areas such as at-home healthcare and home automation, independent living and assistive technology. Initiatives towards interoperability and standardization are taken by several players. Zigbee Alliance has launched a profile for “Zigbee wireless sensor applications for health, wellness and fitness” [1]. The Continua Health Alliance promotes “an interoperable personal healthcare ecosystem”. They have published “design guidelines for the telehealth ecosystem” including the interface to personal area network health devices and electronic health record devices ([2], [3]). These examples show that wireless personal area networks, including body sensor networks, are becoming more mature and are considered to be a realistic alternative as communication infrastructure for demanding services. However, to transmit vital sign parameters from ECGs, pulse-oximeters, EEGs etc in wireless networks is also a challenge, especially if multiple sensors compete for access. Contention-based access networks offer simplicity and utilization advantages, but the drawback is unpredictable performance due to loss of transmitted packets.

    We have used the SHIMMER wireless sensor platform developed at Intel [4] in the living lab at the Centre for Health and Building at KTH in a case study to identify and evaluate performance problems. The full-scale living lab consists of two apartments especially equipped with modern technique for healthcare at home and assisted living.

    Our paper focuses on continuous monitoring of the heart activity using a wireless ECG based on the wireless personal area network (WPAN) standard IEEE 802.15.4. Results from performance tests in the living lab will be presented e.g. influence of equipment such as micro wave ovens. Since contention-based wireless access has no guarantees for the quality of the delivered service it is interesting to determine to what extent the received ECG signal is sensitive to loss of information. We have recorded ECG signals as well as emulated packet loss in existing ECG records from official databases. The result of two cardiologists´ assessment of ECGs with different loss ratio levels and patterns will be reported in the paper. One interesting conclusion is that a diagnosis is fully possible for ECGs with packet loss ratio up to at least 5%. This project is part of research at the School of Technology and Health at KTH.

  • 42. Campo, A. B.
    et al.
    Dirckx, J. J.
    Widman, Erik
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Waz, A. T.
    Dudzik, G.
    Abramski, K. M.
    Application of a new four-channel vibrometer for determination of atherosclerosis: Further advances towards a handheld device2016In: 2016 IEEE International Symposium on Medical Measurements and Applications, MeMeA 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    Cardiovascular diseases (CD) are the leading cause of death worldwide and their prevalence is expected to rise. Important in the etiology of CD is the stiffening of the large arteries (arteriosclerosis) and plaque formation (atherosclerosis) in the common carotid artery (CCA). Increasing evidence shows that both arteriosclerosis and atherosclerosis can be detected by assessing pulse wave velocity (PWV) in the CCA, and several techniques focus on the detection of PWV in this structure. In previous studies, laser Doppler vibrometry (LDV) was proposed as an approach to detect arterial stiffness. In the present work, a compact four-channel LDV system is introduced for PWV detection. Four phantom arteries were assessed mimicking real life cardiovascular pathologies. Due to the high sensitivity and the increased spatial and temporal resolution of the LDV system, PWV could be assessed, and even local changes in phantom architecture could be detected. The system could potentially be used to detect arteriosclerosis and arterial plaque during cardiovascular screening.

  • 43.
    Chowdhury, Manish
    et al.
    KTH, School of Technology and Health (STH).
    Jörgens, Daniel
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Wang, Chunliang
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization. KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Segmentation of Cortical Bone using Fast Level Sets2017In: MEDICAL IMAGING 2017: IMAGE PROCESSING / [ed] Styner, MA Angelini, ED, SPIE - International Society for Optical Engineering, 2017, UNSP 1013327Conference paper (Refereed)
    Abstract [en]

    Cortical bone plays a big role in the mechanical competence of bone. The analysis of cortical bone requires accurate segmentation methods. Level set methods are usually in the state-of-the-art for segmenting medical images. However, traditional implementations of this method are computationally expensive. This drawback was recently tackled through the so-called coherent propagation extension of the classical algorithm which has decreased computation times dramatically. In this study, we assess the potential of this technique for segmenting cortical bone in interactive time in 3D images acquired through High Resolution peripheral Quantitative Computed Tomography (HR-pQCT). The obtained segmentations are used to estimate cortical thickness and cortical porosity of the investigated images. Cortical thickness and Cortical porosity is computed using sphere fitting and mathematical morphological operations respectively. Qualitative comparison between the segmentations of our proposed algorithm and a previously published approach on six images volumes reveals superior smoothness properties of the level set approach. While the proposed method yields similar results to previous approaches in regions where the boundary between trabecular and cortical bone is well defined, it yields more stable segmentations in challenging regions. This results in more stable estimation of parameters of cortical bone. The proposed technique takes few seconds to compute, which makes it suitable for clinical settings.

  • 44.
    Chowdhury, Manish
    et al.
    KTH, School of Technology and Health (STH).
    Klintström, Benjamin
    KTH, School of Technology and Health (STH). Linköping University, Sweden.
    Klintström, E.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization. Linköping University, Sweden.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Granulometry-based trabecular bone segmentation2017In: 20th Scandinavian Conference on Image Analysis, SCIA 2017, Springer, 2017, Vol. 10270, 100-108 p.Conference paper (Refereed)
    Abstract [en]

    The accuracy of the analyses for studying the three dimensional trabecular bone microstructure rely on the quality of the segmentation between trabecular bone and bone marrow. Such segmentation is challenging for images from computed tomography modalities that can be used in vivo due to their low contrast and resolution. For this purpose, we propose in this paper a granulometry-based segmentation method. In a first step, the trabecular thickness is estimated by using the granulometry in gray scale, which is generated by applying the opening morphological operation with ball-shaped structuring elements of different diameters. This process mimics the traditional sphere-fitting method used for estimating trabecular thickness in segmented images. The residual obtained after computing the granulometry is compared to the original gray scale value in order to obtain a measurement of how likely a voxel belongs to trabecular bone. A threshold is applied to obtain the final segmentation. Six histomorphometric parameters were computed on 14 segmented bone specimens imaged with cone-beam computed tomography (CBCT), considering micro-computed tomography (micro-CT) as the ground truth. Otsu’s thresholding and Automated Region Growing (ARG) segmentation methods were used for comparison. For three parameters (Tb.N, Tb.Th and BV/TV), the proposed segmentation algorithm yielded the highest correlations with micro-CT, while for the remaining three (Tb.Nd, Tb.Tm and Tb.Sp), its performance was comparable to ARG. The method also yielded the strongest average correlation (0.89). When Tb.Th was computed directly from the gray scale images, the correlation was superior to the binary-based methods. The results suggest that the proposed algorithm can be used for studying trabecular bone in vivo through CBCT.

  • 45.
    Chowdhury, Manish
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Rota Bulò, S.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Kundu, M.K.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    An Efficient Radiographic Image Retrieval System Using Convolutional Neural Network2016In: 2016 23rd International Conference on Pattern Recognition (ICPR), Institute of Electrical and Electronics Engineers (IEEE), 2016, 3134-3139 p., 7900116Conference paper (Refereed)
    Abstract [en]

    Content-Based Medical Image Retrieval (CBMIR) is an important research field in the context of medical data management. In this paper we propose a novel CBMIR system for the automatic retrieval of radiographic images. Our approach employs a Convolutional Neural Network (CNN) to obtain high- level image representations that enable a coarse retrieval of images that are in correspondence to a query image. The retrieved set of images is refined via a non-parametric estimation of putative classes for the query image, which are used to filter out potential outliers in favour of more relevant images belonging to those classes. The refined set of images is finally re-ranked using Edge Histogram Descriptor, i.e. a low-level edge-based image descriptor that allows to capture finer similarities between the retrieved set of images and the query image. To improve the computational efficiency of the system, we employ dimensionality reduction via Principal Component Analysis (PCA). Experiments were carried out to evaluate the effectiveness of the proposed system on medical data from the “Image Retrieval in Medical Applications” (IRMA) benchmark database. The obtained results show the effectiveness of the proposed CBMIR system in the field of medical image retrieval.

  • 46. Cippitelli, E.
    et al.
    Gasparrini, S.
    Gambi, E.
    Spinsante, S.
    Wåhslén, Jonas
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Time synchronization and data fusion for RGB-Depth cameras and inertial sensors in AAL applications2015In: 2015 IEEE International Conference on Communication Workshop, ICCW 2015, IEEE conference proceedings, 2015, 265-270 p.Conference paper (Refereed)
    Abstract [en]

    Ambient Assisted Living applications often need to integrate data from multiple sensors, to provide consistent information on the observed phenomena. Data fusion based on samples from several sensors requires accurate time synchronization with sufficient resolution, depending on the sensor sampling frequency. This work presents a technical platform for the efficient and accurate synchronization of the data captured from RGB-Depth cameras and wearable inertial sensors, that can be integrated in AAL solutions. A case study of sensor data fusion for Timed Up and Go test is also presented and discussed.

  • 47.
    Cloots, Rudy J.H.
    et al.
    Eindhoven University of Technology, Department of Mechanical Engineering.
    van Dommelen, JAW
    Eindhoven University of Technology, Department of Mechanical Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Geers, Marc
    Eindhoven University of Technology, Department of Mechanical Engineering.
    Traumatic Brain Injury at Multiple Length Scales: Relating Diffuse Axonal Injury to Discrete Axonal Impairment2010In: 2010 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF INJURY PROCEEDINGS, 2010, 119-130 p.Conference paper (Refereed)
  • 48.
    Cuba-Gyllensten, Illapha
    et al.
    KTH, School of Technology and Health (STH). Philips Research Europe, High Tech. Campus 34, 5656AE, Eindhoven, Netherlands; ACTLab., Signal Processing Systems, TU Eindhoven, 5600MB Eindhoven, Netherlands.
    Abtahi, Farhad
    Philips Research Europe, High Tech. Campus 34, 5656AE, Eindhoven, Netherlands.
    Bonomi, Alberto G.
    KTH, School of Technology and Health (STH).
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institute, Sweden.
    Amft, O.
    ACTLab., Signal Processing Systems, TU Eindhoven, 5600MB Eindhoven, Netherlands.
    Removing respiratory artefacts from transthoracic bioimpedance spectroscopy measurements2013In: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT), Institute of Physics Publishing (IOPP), 2013, Vol. 434, no 1Conference paper (Refereed)
    Abstract [en]

    Transthoracic impedance spectroscopy (TIS) measurements from wearable textile electrodes provide a tool to remotely and non-invasively monitor patient health. However, breathing and cardiac processes inevitably affect TIS measurements, since they are sensitive to changes in geometry and air or fluid volumes in the thorax. This study aimed at investigating the effect of respiration on Cole parameters extracted from TIS measurements and developing a method to suppress artifacts. TIS data were collected from 10 participants at 16 frequencies (range: 10 kHz - 1 MHz) using a textile electrode system (Philips Technologie Gmbh). Simultaneously, breathing volumes and frequency were logged using an electronic spirometer augmented with data from a breathing belt. The effect of respiration on TIS measurements was studied at paced (10 and 16 bpm) deep and shallow breathing. These measurements were repeated for each subject in three different postures (lying down, reclining and sitting). Cole parameter estimation was improved by assessing the tidal expiration point thus removing breathing artifacts. This leads to lower intra-subject variability between sessions and a need for less measurements points to accurately assess the spectra. Future work should explore algorithmic artifacts compensation models using breathing and posture or patient contextual information to improve ambulatory transthoracic impedance measurements.

  • 49. Cunico, F. J.
    et al.
    Marquez, Juan Carlos
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Hilke, H.
    Skrifvars, M.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Studying the performance of conductive polymer films as textile electrodes for electrical bioimpedance measurements2013In: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT), 2013, Vol. 434, no 1, 012027- p.Conference paper (Refereed)
    Abstract [en]

    With the goal of finding novel biocompatible materials suitable to replace silver in the manufacturing of textile electrodes for medical applications of electrical bioimpedance spectroscopy, three different polymeric materials have been investigated. Films have been prepared from different polymeric materials and custom bracelets have been confectioned with them. Tetrapolar total right side electrical bioimpedance spectroscopy (EBIS) measurements have been performed with polymer and with standard gel electrodes. The performance of the polymer films was compared against the performance of the gel electrodes. The results indicated that only the polypropylene 1380 could produce EBIS measurements but remarkably tainted with high frequency artefacts. The influence of the electrode mismatch, stray capacitances and large electrode polarization impedance are unclear and they need to be clarified with further studies. If sensorized garments could be made with such biocompatible polymeric materials the burden of considering textrodes class III devices could be avoided.

  • 50. Daudi, M.
    et al.
    Hauge, Jannicke
    KTH, School of Technology and Health (STH). University of Bremen, Germany.
    Thoben, K. -D
    Effects of decision synchronization on trust in collaborative networks2016In: 17th IFIP WG 5.5 Working Conference on Virtual Enterprises, PRO-VE 2016, Springer-Verlag New York, 2016, 215-227 p.Conference paper (Refereed)
    Abstract [en]

    In collaborative networks, individual and organizational entities encounter many disagreements over many decisions rights. These disagreements procreate conflicting preferences, which in turn, affect trustworthy amongst partners. To that end, it becomes necessary that partners assume a degree of fairness on decision rights by calibrating positions which they initially consider a final. This calibration involves synchronizing partners’ conflicting preferences to a compromise. The objective of this paper, therefore, is to analyze and evaluate the effect of both, compromised and uncompromised preferences on trust. To achieve this, a corresponding behavioral trust model is proposed and evaluated empirically using a logistics collaboration scenario. This evaluation applies a multi-agent systems simulation method. The simulation involves 360 observations with three preferences set as predictor variables. Results show that irrespective of a degree to which conflicting preferences are synchronized, a magnitude of the generated effect on trust, depends as well on other factors like transport cost and extent to which vehicles are loaded. Additionally, if other factors are kept constant, compromised preferences affects trust more positively than uncompromised ones.

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