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  • 1.
    Josefsson, Mattias
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    3D camera with built-in velocity measurement2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In today's industry 3D cameras are often used to inspect products. The camera produces both a 3D model and an intensity image by capturing a series of profiles of the object using laser triangulation. In many of these setups a physical encoder is attached to, for example, the conveyor belt that the product is travelling on. The encoder is used to get an accurate reading of the speed that the product has when it passes through the laser. Without this, the output image from the camera can be distorted due to a variation in velocity.

    In this master thesis a method for integrating the functionality of this physical encoder into the software of the camera is proposed. The object is scanned together with a pattern, with the help of this pattern the object can be restored to its original proportions.

  • 2. Imura, M
    et al.
    Kuroda, T
    Oshiro, O
    Chihara, K
    Brandberg, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    3-D flow visualization for construction of the model of the blood flow in the heart2000In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 39, no 5 B, 3246-3251 p.Article in journal (Refereed)
    Abstract [en]

    The authors have been developing a model of blood flow in the heart. The flow model of the heart enables us to estimate the entire blood flow of the heart from a couple of 2-D color Doppler images. Therefore, the load on patients is expected to be reduced. To develop the model of the heart, precise observation and an understanding of the blood flow are indispensable, because the flow is strongly related to the diagnosis of heart diseases. The visualization method must have the following features: (1) 3-D (2) objectivity (3) interactivity and (4) multi-aspect. The authors have developed visualization methods to meet the above-mentioned requirements and evaluated the proposed methods with the in-vitro flow data set. The results clearly reveal that the proposed system enables the researchers of the modeling group to obtain the state of entire flow, such as the occurrence of turbulence.

  • 3. Comina, German
    et al.
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Filippini, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    3D Printed Unibody Lab-on-a-Chip: Features Survey and Check-Valves Integration dagger2015In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 6, no 4, 437-451 p.Article in journal (Refereed)
    Abstract [en]

    The unibody lab-on-a-chip (ULOC) concept entails a fast and affordable micro-prototyping system built around a single monolithic 3D printed element (unibody). A consumer-grade stereo lithography (SL) 3D printer can configure ULOCs with different forms of sample delivery, transport, handling and readout, while minimizing material costs and fabrication time. ULOC centralizes all complex fabrication procedures and replaces the need for clean room resources, delivering prototypes for less than 1 US$, which can be printed in 10 min and ready for testing in less than 30 min. Recent examples of ULOC integration of transport, chemical sensing for optical readout and flow mixing capabilities are discussed, as well as the integration of the first check-valves for ULOC devices. ULOC valves are strictly unidirectional up to 100 psi, show an exponential forward flow behavior up to 70 psi and can be entirely fabricated with the ULOC approach.

  • 4.
    Lofgren, PM
    et al.
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Gu, CY
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Ji, W
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    3-d thermal and flow modeling of hot wall epitaxial chemical vapor deposition reactors, heated by induction2000In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 338-3, 153-156 p.Article in journal (Refereed)
    Abstract [en]

    A three dimensional computational model for temperature and flow predictions in hot wall chemical vapor deposition (CVD) reactors, heated by induction, is presented. It includes heating by a Radio Frequency (RF) coil, flow and heat transfer. Thermal radiation is modeled by a modified Monte Carlo method. Model predictions are compared to full scale experiments at Linkoping CVD reactor for epitaxial growth of silicon carbide (SIC). Both streamwise and spanwise temperature gradients are well predicted, with the temperature maximum location shifted slightly upstream compared to the measured. Additionally, the model succeeds in predicting a recirculation zone just downstream of the susceptor. It is demonstrated how thermal gradients can be greatly reduced by simple geometrical changes.

  • 5.
    Fredriksson, Alexandru G
    et al.
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Zajac, Jakub
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Eriksson, Jonatan
    Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Physiology.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Bolger, Ann F
    University of California San Francisco.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Carlhäll, Carljohan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    4-D blood flow in the human right ventricle2011In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 301, no 6, H2344-H2350 p.Article in journal (Refereed)
    Abstract [en]

    Right ventricular (RV) function is a powerful prognostic indicator in many forms of heart disease, but its assessment remains challenging and inexact. RV dysfunction may alter the normal patterns of RV blood flow, but those patterns have been incompletely characterized. We hypothesized that, based on anatomic differences, the proportions and energetics of RV flow components would differ from those identified in the left ventricle (LV) and that the portion of the RV inflow passing directly to outflow (Direct Flow) would be prepared for effective systolic ejection as a result of preserved kinetic energy (KE) compared with other RV flow components. Three-dimensional, time-resolved phase-contrast velocity, and balanced steady-state free-precession morphological data were acquired in 10 healthy subjects using MRI. A previously validated method was used to separate the RV and LV end-diastolic volumes into four flow components and measure their volume and KE over the cardiac cycle. The RV Direct Flow: 1) followed a smoothly curving route that did not extend into the apical region of the ventricle; 2) had a larger volume and possessed a larger presystolic KE (0.4 +/- 0.3 mJ) than the other flow components (P andlt; 0.001 and P andlt; 0.01, respectively); and 3) represented a larger part of the end-diastolic blood volume compared with the LV Direct Flow (P andlt; 0.01). These findings suggest that diastolic flow patterns distinct to the normal RV create favorable conditions for ensuing systolic ejection of the Direct Flow component. These flow-specific aspects of RV diastolic-systolic coupling provide novel perspectives on RV physiology and may add to the understanding of RV pathophysiology.

  • 6.
    Dyverfeldt, Petter
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bissell, Malenka
    University of Oxford, England.
    Barker, Alex J.
    Northwestern University, IL 60611 USA.
    Bolger, Ann F
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. University of Calif San Francisco, CA USA.
    Carlhäll, Carljohan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Francios, Christopher J.
    University of Wisconsin, WI 53706 USA.
    Frydrychowicz, Alex
    University Hospital Schleswig Holstein, Germany.
    Geiger, Julia
    University of Childrens Hospital Zurich, Switzerland.
    Giese, Daniel
    University Hospital Cologne, Germany.
    Hope, Michael D.
    University of Calif San Francisco, CA USA.
    Kilner, Philip J.
    University of London Imperial Coll Science Technology and Med, England.
    Kozerke, Sebastian
    University of Zurich, Switzerland; ETH, Switzerland.
    Myerson, Saul
    University of Oxford, England.
    Neubauer, Stefan
    University of Oxford, England.
    Wieben, Oliver
    University of Wisconsin, WI 53706 USA.
    Markl, Michael
    Northwestern University, IL 60611 USA; Northwestern University, IL 60611 USA.
    4D flow cardiovascular magnetic resonance consensus statement2015In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 17, no 72Article, review/survey (Refereed)
    Abstract [en]

    Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5x1.5x1.5 - 3x3x3 mm(3), typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.

  • 7.
    Fredriksson, Alexandru Grigorescu
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Örebrö University Hospital, Örebro, Sweden.
    Svalbring, Emil
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Eriksson, Jonatan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Alehagen, Urban
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Faculty of Medicine and Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Faculty of Science & Engineering. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Carlhäll, Carl-Johan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    4D flow MRI can detect subtle right ventricular dysfunction in primary left ventricular disease.2016In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 43, no 3, 558-565 p.Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To investigate whether 4D flow magnetic resonance imaging (MRI) can detect subtle right ventricular (RV) dysfunction in primary left ventricular (LV) disease.

    MATERIALS AND METHODS: 4D flow and morphological 3T MRI data were acquired in 22 patients with mild ischemic heart disease who were stratified into two groups based on LV end-diastolic volume index (EDVI): lower-LVEDVI and higher-LVEDVI, as well as in 11 healthy controls. The RV volume was segmented at end-diastole (ED) and end-systole (ES). Pathlines were emitted from the ED volume and traced forwards and backwards in time to ES. The blood volume was separated into flow components. The Direct Flow (DF) component was defined as RV inflow passing directly to outflow. The kinetic energy (KE) of the DF component was calculated. Echocardiographic conventional RV indices were also assessed.

    RESULTS: The higher-LVEDVI group had larger LVEDVI and lower LV ejection fraction (98 ± 32 ml/m(2) ; 48 ± 13%) compared to the healthy (67 ± 12, P = 0.002; 64 ± 7, P < 0.001) and lower-LVEDI groups (62 ± 10; 68 ± 7, both P < 0.001). The RV 4D flow-specific measures "DF/EDV volume-ratio" and "DF/EDV KE-ratio at ED" were lower in the higher-LVEDVI group (38 ± 5%; 52 ± 6%) compared to the healthy (44 ± 6; 65 ± 7, P = 0.018 and P < 0.001) and lower-LVEDVI groups (44 ± 6; 64 ± 7, P = 0.011 and P < 0.001). There was no difference in any of the conventional MRI and echocardiographic RV indices between the three groups.

    CONCLUSION: We found that in primary LV disease mild impairment of RV function can be detected by 4D flow-specific measures, but not by the conventional MRI and echocardiographic indices. J. Magn. Reson. Imaging 2015.

  • 8.
    Casas Garcia, Belén
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Lantz, Jonas
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Faculty of Science & Engineering. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    4D Flow MRI-Based Pressure Loss Estimation in Stenotic Flows: Evaluation Using Numerical Simulations2016In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 75, no 4, 1808-1821 p.Article in journal (Refereed)
    Abstract [en]

    Purpose: To assess how 4D flow MRI-based pressure and energy loss estimates correspond to net transstenotic pressure gradients (TPG(net)) and their dependence on spatial resolution. Methods: Numerical velocity data of stenotic flow were obtained from computational fluid dynamics (CFD) simulations in geometries with varying stenosis degrees, poststenotic diameters and flow rates. MRI measurements were simulated at different spatial resolutions. The simplified and extended Bernoulli equations, Pressure-Poisson equation (PPE), and integration of turbulent kinetic energy (TKE) and viscous dissipation were compared against the true TPG(net). Results: The simplified Bernoulli equation overestimated the true TPG(net) (8.74 +/- 0.67 versus 6.76 +/- 0.54 mmHg). The extended Bernoulli equation performed better (6.57 +/- 0.53 mmHg), although errors remained at low TPG(net). TPG(net) estimations using the PPE were always close to zero. Total TKE and viscous dissipation correlated strongly with TPG(net) for each geometry (r(2) &gt; 0.93) and moderately considering all geometries (r(2) = 0.756 and r(2) = 0.776, respectively). TKE estimates were accurate and minorly impacted by resolution. Viscous dissipation was overall underestimated and resolution dependent. Conclusion: Several parameters overestimate or are not linearly related to TPG(net) and/or depend on spatial resolution. Considering idealized axisymmetric geometries and in absence of noise, TPG(net) was best estimated using the extended Bernoulli equation. (C) 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

  • 9.
    Sundbom, Per
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Ahn, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Kornhall, B
    Skane University Hospital, Lund.
    Loebe, M
    Division of Transplant and Assist Devices at Methodist DeBakey Heart & Vascular Centre, Houston, Texas, USA.
    Granfeldt, Hans
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    (556) – Change in Acoustic Fingerprints at Increased Pump Speed During Echocardiographic Ramp Test2014Conference paper (Refereed)
    Abstract [en]

    Purpose

    The continuous flow mechanical circulatory support HeartMate II (Thoratec Corporation, Inc. Pleasanton, USA) (HMII), generates an auditory signal (acoustic fingerprint) that can be registered by routine auscultation. A temporary or permanent change in sound indicates a change in pump function. Previous mock loop studies have shown that changes in acoustic fingerprint are due to changes in speed, so the aim of this study was to see if the acoustic fingerprint changed during an echocardiographic ramp test.

    Methods

    Four stable, event-free patients included in the SoundMate study performed an echocardiographic ramp test. The speed was increased stepwise by 400 rpm between 8 000 and 12 000 rpm, and the left ventricular end diastolic diameter, flow, power consumption and blood pressure were measured. Sounds from HMII were recorded using an iPhone™ (Apple Inc. Cupertino, CA, USA) with the stethoscope application iStethPro™ (Dr. Peter J Bentley, UK) and the frequency map analyzed using the Audacity™ program (Unicode, Ash, Chinen and Crook, USA). The acoustic fingerprint is divided into regions (R1: 1 000-6 500, R2: 8 500-14 000, R3: 15 000-21 000 Hz) and peaks (P1: 0-1 000, P2: 6 500-8 500, P4: 21 000-23 000 Hz) in order to facilitate calculations and clarify changes in frequency.

    Results

    There were significant (p<005) changes in the acoustic fingerprint when increasing the pump speed between 8 000 and 12 000 rpm. In 2/4 patients there were no significant changes in P1, otherwise there were significant changes in all regions and peaks. During the ramp test the power increased in mean 7 W, flow 3,1 L/min and the blood pressure measured with Doppler increased by ~15 mmHg. The left ventricular size decreased with ~2 cm.

    Conclusion

    The acoustic fingerprint changes with pump speed. This implies that when using sound check for detection of pump dysfunction, a new baseline should be set after every adjustment of speed.

  • 10.
    Zuse, Ann
    et al.
    Institute of Medicinal and Pharmaceutical Chemistry, Westphalian Wilhelms-University, Hittorfstrasse 58-62, D-48149 Münster, Germany; Manitoba Institute of Cell Biology, CancerCare Manitoba, Department of Biochemistry and Medical Genetics, Winnipeg, Canada.
    Prinz, Helge
    Institute of Medicinal and Pharmaceutical Chemistry, Westphalian Wilhelms-University, Hittorfstrasse 58-62, D-48149 Münster, Germany.
    Müller, Klaus
    Institute of Medicinal and Pharmaceutical Chemistry, Westphalian Wilhelms-University, Hittorfstrasse 58-62, D-48149 Münster, Germany.
    Schmidt, Peter
    Zentaris GmbH, Weismüllerstrasse 50, D-60314 Frankfurt, Germany.
    Günther, Eckhard G.
    Zentaris GmbH, Weismüllerstrasse 50, D-60314 Frankfurt, Germany.
    Schweizer, Frank
    Department of Chemistry, Univ. Manitoba, Winnipeg, Canada.
    Prehn, Jochen H.M.
    Department of Physiology and RCSI Research Institute, St. Stephen's Green, Dublin, Ireland.
    Los, Marek Jan
    Manitoba Institute of Cell Biology, Cancer Care Manitoba; Manitoba Institute of Child Health; Department of Biochemistry and Medical Genetics; Department of Human Anatomy and Cell Science, University Manitoba, Winnipeg, Canada, .
    9-benzylidene-naphtho[2,3-b]thiophen-4-ones and benzylidene-9(10H)-anthracenones as novel tubulin interacting agents with high apoptosis-inducing activity2007In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 575, no 1-3, 34-45 p.Article in journal (Refereed)
    Abstract [en]

    Tubulin-binding 9-benzylidene-naphtho[2,3-b]thiophen-4-ones 1a and 1b and benzylidene-9(10H)-anthracenone 2 were evaluated for their ability to induce cell death. We examined the effect of the molecules on cell cycle progression, organization of microtubule networks, and apoptosis induction. As determined by flow cytometry, cancer cells were predominantly arrested in metaphase with 4N DNA before cell death occurred. By using indirect immunofluorescence techniques we visualized microtubule depolymerization recognizable by short microtubule fragments scattered around the nucleus. The incubation with 1a and 2 resulted in chromatin condensation, nuclear fragmentation, and cell shrinkage, which are, among others, typical features of apoptotic cell death. Furthermore, time- and dose-dependent induction of apoptosis in SH-SY5Y cells was detected via cleavage of Ac-DEVD-AMC, a fluorigenic substrate for caspase-3. We observed a lower apoptotic activity in neuroblastoma cells overexpressing Bcl-xL, suggesting activation of the mitochondrial apoptosis pathway. Western blot analysis demonstrated that caspase-3, an apoptosis mediator, was activated in a time-dependent manner after exposure of SH-SY5Y cells to drugs 1a and 2. Taken together, the agents investigated in the present study display strong apoptosis-inducing activity and therefore show promise for the development of novel chemotherapeutics.

  • 11.
    Hultman, Martin
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Fredriksson, Ingemar
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Perimed AB, Järfälla-Stockholm, Sweden.
    Larsson, Marcus
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Strömberg, Tomas
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    A 15.6 frames per second 1 megapixel Multiple Exposure Laser Speckle Contrast Imaging setup2017In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648Article in journal (Refereed)
    Abstract [en]

    A multiple exposure laser speckle contrast imaging (MELSCI) setup for visualizing blood perfusion was developed using a field programmable gate array (FPGA), connected to a 1000 frames per second (fps) 1-megapixel camera sensor. Multiple exposure time images at 1, 2, 4, 8, 16, 32 and 64 milliseconds were calculated by cumulative summation of 64 consecutive snapshot images. The local contrast was calculated for all exposure times using regions of 4 × 4 pixels. Averaging of multiple contrast images from the 64-millisecond acquisition was done to improve the signal-to-noise ratio. The results show that with an effective implementation of the algorithm on an FPGA, contrast images at all exposure times can be calculated in only 28 milliseconds. The algorithm was applied to data recorded during a 5 minutes finger occlusion. Expected contrast changes were found during occlusion and the following hyperemia in the occluded finger, while unprovoked fingers showed constant contrast during the experiment. The developed setup is capable of massive data processing on an FPGA that enables processing of MELSCI data in 15.6 fps (1000/64 milliseconds). It also leads to improved frame rates, enhanced image quality and enables the calculation of improved microcirculatory perfusion estimates compared to single exposure time systems.

    The full text will be freely available from 2018-08-07 12:43
  • 12.
    Ahmed, Tanvir
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering.
    Garrido, Mario
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Gustafsson, Oscar
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 512-point 8-parallel pipelined feedforward FFT for WPAN2011In: 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), IEEE , 2011, 981-984 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a 512-point feedforward FFT architecture for wireless personal area network (WPAN). The architecture processes a continuous flow of 8 samples in parallel, leading to a throughput of 2.64 GSamples/s. The FFT is computed in three stages that use radix-8 butterflies. This radix reduces significantly the number of rotators with respect to previous approaches based on radix-2. Besides, the proposed architecture uses the minimum memory that is required for a 512-point 8-parallel FFT. Experimental results show that besides its high throughput, the design is efficient in area and power consumption, improving the results of previous approaches. Specifically, for a wordlength of 16 bits, the proposed design consumes 61.5 mW and its area is 1.43 mm2.

  • 13.
    Curescu, C.
    et al.
    Ericsson Research, Torshamnsgatan 23, Kista, 164 83 Stockholm, Sweden.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    A bidding algorithm for optimized utility-based resource allocation in ad hoc networks2008In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 7, no 12, 1397-1414 p.Article in journal (Refereed)
    Abstract [en]

    This paper proposes a scheme for bandwidth allocation in wireless ad hoc networks. The quality-of-service (QoS) levels for each end-to-end flow are expressed using a resource-utility function, and our algorithms aim to maximize aggregated utility. The shared channel is modeled as a bandwidth resource defined by maximal cliques of mutual interfering links. We propose a novel resource allocation algorithm that employs an auction mechanism in which flows are bidding for resources. The bids depend both on the flow's utility function and the intrinsically derived shadow prices. We then combine the admission control scheme with a utility-aware on-demand shortest path routing algorithm where shadow prices are used as a natural distance metric. As a baseline for evaluation, we show that the problem can be formulated as a linear programming (LP) problem. Thus, we can compare the performance of our distributed scheme to the centralized LP solution, registering results very close to the optimum. Next, we isolate the performance of price-based routing and show its advantages in hotspot scenarios, and also propose an asynchronous version that is more feasible for ad hoc environments. Further experimental evaluation compares our scheme with the state of the art derived from Kelly's utility maximization framework and shows that our approach exhibits superior performance for networks with increased mobility or less frequent allocations. © 2008 IEEE.

  • 14.
    Hult, Peter
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Arts and Sciences.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    A bioacoustic method for timing of the different phases of the breathing cycle and monitoring of breathing frequency.2000In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 22, no 6, 425-433 p.Article in journal (Refereed)
    Abstract [en]

    It is well known that the flow of air through the trachea during respiration causes vibrations in the tissue near the trachea, which propagate to the surface of the body and can be picked up by a microphone placed on the throat over the trachea. Since the vibrations are a direct result of the airflow, accurate timing of inspiration and expiration is possible. This paper presents a signal analysis solution for automated monitoring of breathing and calculation of the breathing frequency. The signal analysis approach uses tracheal sound variables in the time and frequency domains, as well as the characteristics of the disturbances that can be used to discriminate tracheal sound from noise. One problem associated with the bioacoustic method is its sensitivity for acoustic disturbances, because the microphone tends to pick up all vibrations, independent of their origin. A signal processing method was developed that makes the bioacoustic method clinically useful in a broad variety of situations, for example in intensive care and during certain heart examinations, where information about both the precise timing and the phases of breathing is crucial.

  • 15.
    Hult, Peter
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    A bioacoustic method for timing of the different phases of the breathing cycle and monitoring of breathing frequency2000In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 22, no 6, 425-433 p.Article in journal (Refereed)
    Abstract [en]

    It is well known that the flow of air through the trachea during respiration causes vibrations in the tissue near the trachea, which propagate to the surface of the body and can be picked up by a microphone placed on the throat over the trachea. Since the vibrations are a direct result of the airflow, accurate timing of inspiration and expiration is possible. This paper presents a signal analysis solution for automated monitoring of breathing and calculation of the breathing frequency. The signal analysis approach uses tracheal sound variables in the time and frequency domains, as well as the characteristics of the disturbances that can be used to discriminate tracheal sound from noise. One problem associated with the bioacoustic method is its sensitivity for acoustic disturbances, because the microphone tends to pick up all vibrations, independent of their origin. A signal processing method was developed that makes the bioacoustic method clinically useful in a broad variety of situations, for example in intensive care and during certain heart examinations, where information about both the precise timing and the phases of breathing is crucial.

  • 16.
    Wallsten, Björn
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Johansson, Nils
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Krook, Joakim
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    A Cable Laid Is a Cable Played: On the Hibernation Logic behind Urban Infrastructure Mines2013In: The Journal of urban technology, ISSN 1063-0732, E-ISSN 1466-1853, Vol. 20, no 3, 85-103 p.Article in journal (Refereed)
    Abstract [en]

    Our societies are reliant on metals to such an extent that the total amounts of some of them in the built environment are comparable in size to the remaining amounts in known mountain ores. Because of concerns about mineral scarcity, the United Nations has assessed alternative sources for metal extraction and targeted urban areas in general and infrastructure systems in particular, since these are large, spatially concentrated and rich in metals. Referring to the possibility of recovering these metal stocks, infrastructure systems constitute what material flow researchers has conceptually termed “urban mines.” While most urban infrastructure is in use, significant amounts of cables and pipes have been disconnected and remain in their subsurface locations; they are “hibernating.” In this article, we analyze the occurrence of such hibernation in the Swedish city of Norrköping's urban infrastructure mine where, we know from a previous study, that every fourth kilo of infrastructure is discarded. Our applied perspective is different from the logic of system expansion as a way to meet increased demand often found in the field of infrastructure studies since we are interested in how systems are disconnected and left behind. This enables us to offer a refined understanding of the concepts of infrastructure “decline” and infrastructure “cold spots.” We argue that to prevent the increase of dormant infrastructures and to engage in the urban mining of already dormant infrastructures, we must develop a sensibility to the materiality of derelict infrastructure components and the underlying causes for why they form different kinds of spatial patterns.

  • 17.
    Rankin, Amy
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Dahlbäck, Nils
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Lundberg, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    A case study of factor influencing role improvisation in crisis response teams2013In: Cognition, Technology & Work, ISSN 1435-5558, E-ISSN 1435-5566, Vol. 15, no 1, 79-93 p.Article in journal (Refereed)
    Abstract [en]

    Common characteristics of crisis situations are ambiguous and unplanned for events. The need for improvised roles can therefore be an imperative factor for the success of an operation. The aim of this study is to deepen the understanding of the processes taking place during improvised work ‘‘as it happens’’. A case study of a crisis management team at work is presented and provides an in-depth analysis of the information and communication flow of persons acting in improvised roles, including con- textual factors influencing the task at hand. The analysis suggests that three main factors lay behind decreased per- formance by the team when some of its members were forced to take on roles for which they lacked professional training; lack of language skills, lack of domain knowledge and insufficient organizational structure of the tasks. Based on the observations from this case study, we suggest three ways of improving a team’s performance and hence resil- ience when forced to improvise due to lack of personnel in one or more required competence areas. These are training to take on the responsibility for tasks or roles outside ones professional area of specialization, developing formal routines for changes in roles and tasks and developing and using tools and routines for information sharing.

  • 18.
    Svensson, Marlene
    Linköping University, Department of Management and Engineering.
    A CFD Investigation of a Generic Bump and its Application to a Diverterless Supersonic Inlet2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This is a Master Thesis done at the Swedish Defence Research Agency with the purpose to design and investigate how different geometries of a compression surface integrated with an intake affects the performance such as distortion, boundary layer diversion, pressure recovery and deceleration of speed.

    The work was divided in two parts. In the first part, CFD calculations using the FOI developed Edge 4.1 code were made for the compression surfaces alone. In the second part the most promising design was integrated with an intake. Two more bumps with the intake were modelled and the three geometries were compared to the intake without bump. Surface flow, deceleration of Mach number, pressure recovery, mass flow, boundary layer diversion, lift and drag were the factors chosen to be examined, boundary layer diversion and pressure recovery being the two most vital.

  • 19.
    Lind, Malin
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Josefsson, Karl Johan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    A CFD Method for Simulation of Gas-Liquid Flow in Cooling Systems: An Eulerian-Eulerian Approach2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When designing modern engines it is important to construct a cooling system that cools the engine structure efficiently. Within the cooling system there is always a certain amount of air which can accumulate and form air pockets in critical areas, such as the water jacket, which can lead to wall degradation. A Computational Fluid Dynamics (CFD) method in STAR-CCM+ from CD-adapco, was derived at Volvo Cars in order to study the accumulation of air bubbles in the water jacket. The method was derived by investigating and evaluating already existing methods. The method initially considered as the best suited was the Eulerian-Eulerian approach. The method was validated against three simpler geometries where experimental data was available. The Eulerian-Eulerian approach treats both phases, liquid and gas, as continuous phases. The idea with the method is to solve the Navier-Stokes equation, the continuity equation and the energy equation for both phases using the Eulerian approach, therefore called Eulerian-Eulerian. The interaction between the two phases was important to model properly which was done by including several interaction models within STAR-CCM+. By tuning different coefficients, which were investigated by a thorough parameter study, the method resembled the experimental data in a satisfying way. The best suited mesh for these simpler geometries was a directed mesh. However, the mesh in the water jacket was automatically generated by STAR-CCM+ and the simpler cases were therefore validated with an automated mesh as well. To capture the experimental data the convection scheme for volume fraction had to be of second order when simulating with automated mesh. This resulted in convergence issues when implementing the method on the water jacket. Instead first order convection scheme, which did not present as satisfying results as second order, had to be implemented. Simulations of the water jacket were performed with two different velocities, that were 10 m/s and 19 m/s, and different flow split ratios for the three outlets. Air with volume fraction 0.1 was injected at the inlet during the first 0.5 s followed by 0.5-1.1 s of further simulation without injecting air. Increased velocity resulted in increased flow through of gas, whereas no big difference could be seen between the different outlet flow split ratios. At two different zones lower pressure was found which resulted in gas holdup. To be able to validate the results from the water jacket, experiments would be necessary to perform in order to provide experimental data for comparison. Velocity profiles from the derived two-phase method resemble the velocity profiles from the one-phase simulation from Volvo, which indicated that the two-phase method did not affect the solution in a remarkable way. Granted that the zones of lower pressure and gas holdup normally coincides, the pressure field from the one-phase simulation could be directly studied, which would lower the computational costs significantly.

  • 20.
    Desai, Avni
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Widgren, Maria
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    A Collaboration in Product Service System for Telecom Networks: An "Orange and Ericsson case" study2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of the research is to study the “Orange and Ericsson case” while developing the method Actors and System Map. The interaction between actors within Ericsson’s Device Connection Platform is investigated in order to identify improvement opportunities in the interaction between the provider and the customer. To answer the purpose the following research questions was formulated:

    RQ1)  What type of actors may be involved in a telecom related IPSO?

    RQ2)  How can the connections between actors in the telecom related IPSO be illustrated?

    RQ3)  How can the Actors and System Map method be refined?

    In order to answer the research questions different methodologies were used for the analysing process. The research started with a widespread literature study to collect knowledge related to the area of Product Service System (PSS) and methodologies for identifying how actors interact with one another. Studying different mapping methods the conclusion was made that Actors and System Map was most suitable for this study.

    In the methodology background the previous selected method, Actors and System Map from an Integrated Product Service Offering (IPSO) perspective, was examined in order to be able to refine and improve the mapping method. Actors Map provides a visual and clear overview of the actors involved while a System Map shows the information flows and activities between the actors.

    To understand the interaction between the two companies, the definition of IPSO and the importance of value-based selling for a service offering are described in the theory background. Also, different ways of looking at a business model within the telecommunication industry is presented.

    Obtaining information regarding making an Actors Map and a System Map an improved mapping method was refined. The adaption of the method was divided into eight steps. The refined Actors Maps of the DCP shows the actors involved, how they are connected and their main assignments from each respondent’s point of view at Ericsson. The refined System Map shows what kind of information is transferred between the actors within the companies and between Orange and Ericsson. Both maps delivered as a decision basis will help identification of non-value giving links and non-optimal distances in the information flow for both companies.

  • 21.
    Larsson, Torbjörn
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Patriksson, Michael
    Matematiska vetenskaper Chalmers tekniska högskola.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    A column generation procedure for the side constrained traffic equilibrium problem2004Article in journal (Refereed)
    Abstract [en]

    We present a column generation procedure for the side constrained traffic equilibrium problem. A dual stabilization scheme is introduced to improve the computational performance. Computational experiments for the case of linear side constraints are presented. The test problems are well known traffic equilibrium instances where side constraints of link flow capacity type and general linear side constraints are added. The computational results are promising especially for instances with a relatively small number of side constraints.

  • 22.
    Jung, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Yew Ng, Kok
    Monash University, Malaysia.
    Frisk, Erik
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Krysander, Mattias
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    A combined diagnosis system design using model-based and data-driven methods2016In: 2016 3RD CONFERENCE ON CONTROL AND FAULT-TOLERANT SYSTEMS (SYSTOL), IEEE , 2016, 177-182 p.Conference paper (Refereed)
    Abstract [en]

    A hybrid diagnosis system design is proposed that combines model-based and data-driven diagnosis methods for fault isolation. A set of residuals are used to detect if there is a fault in the system and a consistency-based fault isolation algorithm is used to compute all diagnosis candidates that can explain the triggered residuals. To improve fault isolation, diagnosis candidates are ranked by evaluating the residuals using a set of one-class support vector machines trained using data from different faults. The proposed diagnosis system design is evaluated using simulations of a model describing the air-flow in an internal combustion engine.

  • 23.
    Jung, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Ng, Kok Yew
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Frisk, Erik
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Krysander, Mattias
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    A combined diagnosis system design using model-based and data-driven techniques2016Conference paper (Refereed)
    Abstract [en]

    A hybrid diagnosis system design is proposed that combines model-based and data-driven diagnosis methods for fault isolation. A set of residuals are used to detect if there is a fault in the system and a consistency-based fault isolation algorithm is used to compute all diagnosis candidates that can explain the triggered residuals. To improve fault isolation, diagnosis candidates are ranked by evaluating the residuals using a set of one-class support vector machines trained using data from different faults. The proposed diagnosis system design is evaluated using simulations of a model describing the air-flow in an internal combustion engine.

  • 24.
    Hildebrand, Cisilia
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Hörtin, Stina
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A comparative study between Emme and Visum with respect to public transport assignment2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Macroscopic traffic simulations are widely used in the world in order to provide assistance in the traffic infrastructure development as well as for the strategic traffic planning. When studying a large traffic network macroscopic traffic simulation can be used to model current and future traffic situations. The two most common software used for traffic simulation in Sweden today are Emme and Visum, developed by INRO respective PTV.

    The aim of the thesis is to perform a comparison between the software Emme and Visum with respect to the assignment of public transport, in other words how passengers choose their routes on the existing public transport lines. However, in order to make a complete software comparison the run-time, analysis capabilities, multi-modality, capacity to model various behavioural phenomena like crowding, fares etc. this will not be done in this comparison. It is of interest to study the differences between the two software algorithms and why they might occur because the Swedish Transport Administration uses Emme and the Traffic Administration in Stockholm uses Visum when planning public transport. The comparison will include the resulting volumes on transit lines, travel times, flow through specific nodes, number of boarding, auxiliary volumes and number of transits. The goal of this work is to answer the following objective: What are the differences with modelling a public transport network in Emme and in Visum, based on that the passengers only have information about the travel times and the line frequency, and why does the differences occur?

    In order to evaluate how the algorithms work in a larger network, Nacka municipality (in Stockholm) and the new metro route between Nacka Forum and Kungsträdgården have been used. The motivation for choosing this area and case is due to that it is interesting to see what differences could occur between the programs when there is a major change in the traffic network.

    The network of Nacka, and parts of Stockholm City, has been developed from an existing road network of Sweden and then restricted by "cutting out" the area of interest and then removing all public transportation lines outside the selected area. The OD-matrix was also limited and in order not to loose the correct flow of travellers portal zones was used to collect and retain volumes.

    To find out why the differences occur the headway-based algorithms in each software were studied carefully. An example of a small and simple network (consisting of only a start and end node) has been used to demonstrate and show how the algorithms work and why volumes split differently on the existing transit lines in Emme and Visum. The limited network of Nacka shows how the different software may produce different results in a larger public transport network.

    The results show that there are differences between the program algorithms but the significance varies depending on which output is being studied and the size of the network. The Visum algorithm results in more total boardings, i.e. more passengers have an optimal strategy including a transit. The algorithms are very similar in both software programs, since they include more or less parts of the optimal strategy. The parameters used are taken more or less into consideration in Emme and Visum. For example Visum will first of all focus on the shortest total travel time and then consider the other lines with respect to the maximum waiting time. Emme however, first focuses on the shortest travel time and then considers the total travel time for other lines with half the waiting time instead of the maximum wait time. This results in that less transit lines will be attractive in Emme compared to Visum. The thesis concludes that varying the parameters for public transport in each software algorithm one can obtain similar results, which implies that it is most important to choose the best parameter values and not to choose the "best" software when simulating a traffic network.

  • 25.
    Schmidt, Susann
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary.
    Wissting, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    A comparative study of direct current magnetron sputtering and high power impulse magnetron sputtering processes for CNX thin film growth with different inert gases2016In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 64, 13-26 p.Article in journal (Refereed)
    Abstract [en]

    Reactive direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) discharges of carbon in different inert gas mixtures (N-2/Ne, N-2/Ar, and N-2/Kr) were investigated for the growth of carbon-nitride (CNX) thin films. Ion mass spectrometry showed that energies of abundant plasma cations are governed by the inert gas and the N-2-to-inert gas flow ratios. The population of ion species depends on the sputter mode; HiPIMS yields approximately ten times higher flux ratios of ions originating from the target to process gas ions than DCMS. Exceptional are discharges in Ne with N-2-to-Ne flow ratios &lt;20%. Here, cation energies and the amount of target ions are highest without influence on the sputter mode. CNX thin films were deposited in 14% N-2/inert gas mixtures at substrate temperatures of 110 degrees C and 430 degrees C. The film properties show a correlation to the substrate temperature, the applied inert gas and sputter mode. The mechanical performance of the films is mainly governed by their morphology and composition, but not by their microstructure. Amorphous and fullerene-like CN0.14 films exhibiting a hardness of similar to 15 GPa and an elastic recovery of similar to 90% were deposited at 110 degrees C in reactive Kr atmosphere by DCMS and HiPIMS.

  • 26.
    Sundquist, Marie
    et al.
    Department of Surgery, County Hospital, Kalmar, Sweden.
    Thorstenson, Sten
    Department of Cytology and Pathology, County Hospital, Kalmar, Sweden.
    Brudin, Lars
    Department of Physiology, County Hospital, Kalmar, Sweden.
    Stål, Olle
    Linköping University, Department of Biomedicine and Surgery, Oncology. Linköping University, Faculty of Health Sciences.
    Nordenskjöld, Bo
    Linköping University, Department of Biomedicine and Surgery, Oncology. Linköping University, Faculty of Health Sciences.
    A comparison between flow cytometric assessment of S-phase fraction and Nottingham histologic grade as prognostic instruments in breast cancer2000In: Breast Cancer Research and Treatment, ISSN 0167-6806, E-ISSN 1573-7217, Vol. 63, no 1, 11-15 p.Article in journal (Refereed)
    Abstract [en]

    Flow cytometric DNA analysis with assessment of S-phase fraction and DNA ploidy was compared to Nottingham histologic grade. The study population consisted of 654 patients who presented between 1987 and 1996 with primary operable breast cancer and whose tumours had been analysed for S-phase fraction and DNA ploidy at the time of surgery. Grade, tumour size, node status, steroid receptor status, age, S-phase fraction and DNA ploidy were analysed univariately and multi-variately in a Cox proportional hazard analysis. In the univariate analyses all parameters were statistically significantly associated with breast cancer mortality during the follow-up period of 2–11 years. The most powerful predictor of death from breast cancer in the multiple regression analysis was grade. Patients with grade 1 tumours have excellent prognosis. We conclude that tumour grade is a strong prognostic indicator applicable to all breast cancer patients, regardless of size and nodal status, and advocate its general use.

  • 27.
    Esamai, Fabian
    et al.
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Mining, Simeon
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Forsberg, Pia
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Lewis, David H.
    A comparison of brain, core and skin temperature in children with complicated and uncomplicated malaria2001In: Journal of Tropical Pediatrics, ISSN 0142-6338, E-ISSN 1465-3664, Vol. 47, no 3, 170-175 p.Article in journal (Refereed)
    Abstract [en]

    A prospective study was carried out in which brain, core and skin temperatures were studied in children with cerebral malaria (n = 23), uncomplicated malaria (n = 12) and normal children (n = 9) using the zero heat flow method. Patients with cerebral or uncomplicated malaria were admitted to the paediatric wards (mean age, 6 years 8 months ± 2 years 8 months). Normal children, children of the investigators, of the same age group, served as controls. Parasitaemia levels were similar in the cerebral and uncomplicated malaria cases. Higher brain than core temperatures would have been expected in cerebral malaria but not in uncomplicated malaria but this was not the case in this study. There was no statistical difference in brain, core and skin temperature between cerebral and uncomplicated malaria patients. However, there was a highly significant difference between normal children and cerebral and uncomplicated malaria patients. Brain temperature was 0.02–0.2°C below core temperature in all the groups with larger differences during the febrile period. Mean differences of brain minus core, brain minus skin and core minus skin between the two groups of patients were not statistically significant. There was no correlation between temperature and the level of coma or parasitaemia for cerebral and uncomplicated malaria patients. There was a positive correlation between brain and core temperature in both groups of patients during the febrile phase. Brain temperature remained lower than core temperature in cerebral and uncomplicated malaria as in normal children. Normal thermoregulation appears to be maintained in cerebral malaria.

  • 28.
    Vogel, K
    Swedish Natl Rd & Transport Res Inst, S-58195 Linkoping, Sweden.
    A comparison of headway and time to collision as safety indicators2003In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 35, no 3, 427-433 p.Article in journal (Refereed)
    Abstract [en]

    The two safety indicators "headway" and "time to collision (TTC)" are discussed and compared with respect to their usefulness in determining the safety of different traffic situations, like different locations in a junction. Over a 6-day-period traffic flow measures were taken in a four-way junction with stop signs on the minor road. It was found that for vehicles in a car following situation headway and TTC are independent of each other. The percentage of small headways is relatively constant across different locations in the junction, while the percentage of small TTC values varies between different locations. It is recommended to use headway for enforcement purposes, because small headways generate potentially dangerous situations. TTC, on the other hand, should be used when a certain traffic environment is to be evaluated in terms of safety, because it indicates the actual occurrences of dangerous situations. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 29.
    Thompson, M.S.
    et al.
    Center for Musculoskeletal Surgery, Charite-University of Medicine, Berlin, Germany.
    Flivik, G.
    Department of Orthopaedics, Lund University Hospital, Lund, Sweden.
    Juliusson, R.
    Department of Orthopaedics, Lund University Hospital, Lund, Sweden.
    Odgaard, A.
    Orthopaedic Research Laboratory, Aarhus University Hospital, Aarhus, Denmark.
    Ryd, Leif
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine .
    A comparison of structural and mechanical properties in cancellous bone from the femoral head and acetabulum2004In: Proceedings of the Institution of mechanical engineers. Part H, journal of engineering in medicine, ISSN 0954-4119, E-ISSN 2041-3033, Vol. 218, no 6, 425-429 p.Article in journal (Refereed)
    Abstract [en]

    Mechanical interlock obtained by penetration of bone cement into cancellous bone is critical to the success of cemented total hip replacement (THR). Although acetabular component loosening is an important mode of THR failure, the properties of acetabular cancellous bone relevant to cement penetration are not well characterized. Bone biopsies (9 mm diameter, 10 mm long) were taken from the articular surfaces of the acetabulum and femoral head during total hip replacement. After mechanical and chemical defatting the two groups of bone specimens were characterized using flow measurement, mechanical testing and finally serial sectioning and three-dimensional computer reconstruction. The mean permeabilities of the acetabular group (1.064 × 10-10 m2) and femoral group (1.155 × 10-10 m2) were calculated from the flow measurements, which used saline solution and a static pressure of 9.8 kPa. The mean Young's modulus, measured non-destructively, was 47.4 MPa for the femoral group and 116.4 MPa for the acetabular group. Three-dimensional computer reconstruction of the specimens showed no significant differences in connectivity and porosity between the groups. Results obtained using femoral head cancellous bone to investigate bone cement penetration and fixation are directly relevant to fixation in the acetabulum. © IMechE 2004.

  • 30.
    Bradshaw-Hajek, B H
    et al.
    University of S Australia, Australia .
    Miklavcic, Stan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ward, D A
    University of S Australia, Australia .
    A composite Level Set and Extended-Domain-Eigenfunction Method for simulating 2D Stokes flow involving a free surface2013In: Journal of Computational and Applied Mathematics, ISSN 0377-0427, E-ISSN 1879-1778, Vol. 237, no 1, 389-402 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, the Extended-Domain-Eigenfunction-Method (EDEM) is combined with the Level Set Method in a composite numerical scheme for simulating a moving boundary problem. The liquid velocity is obtained by formulating the problem in terms of the EDEM methodology and solved using a least square approach. The propagation of the free surface is effected by a narrow band Level Set Method. The two methods both pass information to each other via a bridging process, which allows the position of the interface to be updated. The numerical scheme is applied to a series of problems involving a gas bubble submerged in a viscous liquid moving subject to both an externally generated flow and the influence of surface tension.

  • 31.
    Svensson, Klas
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Rohdin, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A computational parametric study on the development of confluent round jet arrays2015In: European journal of mechanics. B, Fluids, ISSN 0997-7546, E-ISSN 1873-7390, Vol. 53, 129-147 p.Article in journal (Refereed)
    Abstract [en]

    In this study, Computational Fluid Dynamics (CFD) and response surface methodology is employed in a parametrical investigation of an in-line array of confluent round jets. Confluent round jet arrays are common within several fields of engineering, as detailed knowledge of the flow field development of confluent round jets is of great importance to design engineers working with, for example, chemical mixing, multiple jet burners, waste water disposal systems or ventilation supply devices. In this paper, five independent factors affecting flow field development are investigated with a multi-variable approach using a Box–Behnken design method.

    The results include decay of maximum velocity, turbulence intensity, location of merging and combined points and development of volumetric flow rate. Dimensionless nozzle spacing, S/d0S/d0, is an important design parameter and has a large impact on several properties, such as merging and combined points, decay of maximum velocity, and development of turbulence intensity. Other factors, such as the number of jets per row and inlet velocity, are also of importance. The analysis of decay in maximum velocity led to the definition of a new zone of development, referred to as the Confluent Core Zone (CCZ), as its behaviour is reminiscent of the potential core of a single jet. The CCZ has uniform velocity, lacks considerable decay in streamwise velocity and has a rather low turbulence intensity. The CCZ has a characteristic footprint in confluent round jet arrays, and its properties are investigated in detail.

    The development of volumetric flow can be divided into two regions. The initial region, close to the nozzles, features a high entrainment but decreasing entrainment rate. As the jets combine, the entrainment rate is lower, but rather constant. While S/d0S/d0 is generally an important design parameter, there is no direct correlation between S/d0S/d0 and entrainment rate of the combined jet.

  • 32.
    Svärd, Magnus
    et al.
    University of Edinburgh.
    Lundberg, Johan
    Uppsala University.
    Nordström, Jan
    Uppsala universitet, Avdelningen för teknisk databehandling.
    A computational study of vortex-airfoil interaction using high-order finite difference methods2010In: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 39, no 8, 1267-1274 p.Article in journal (Refereed)
    Abstract [en]

    Simulations of the interaction between a vortex and a NACA0012 airfoil are performed with a stable, high-order accurate (in space and time), multi-block finite difference solver for the compressible Navier–Stokes equations.

    We begin by computing a benchmark test case to validate the code. Next, the flow with steady inflow conditions are computed on several different grids. The resolution of the boundary layer as well as the amount of the artificial dissipation is studied to establish the necessary resolution requirements. We propose an accuracy test based on the weak imposition of the boundary conditions that does not require a grid refinement.

    Finally, we compute the vortex–airfoil interaction and calculate the lift and drag coefficients. It is shown that the viscous terms add the effect of detailed small scale structures to the lift and drag coefficients.

  • 33. Sparring Björkstén, Karin
    et al.
    Ekberg, Stefan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Säfström, Pia
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL.
    Dige, N
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    A computerized human reference brain for rCBF/SPET technetium-99m exametazime (HMPAO) investigation of elderly2004In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 24, no 4, 196-204 p.Article in journal (Refereed)
    Abstract [en]

    Using the bull's eye approach, a reference brain from the single photon emission tomography (SPET) images of 10 subjects aged 62-81 years with excellent mental and physical health was constructed. SPET images were acquired twice, 1 week apart, using a single detector rotating gamma camera collecting 64 planar images over a 360° orbit. The centre of each transaxial slice was first defined with an automatic edge detecting algorithm applied to an anterior-posterior and a side profile of the brain. Each slice was divided into 40 sectors. Maximum counts/pixel in each sector was picked. The 40 maximum count values from one transaxial slice were allowed to form a horizontal row in a new parametric image on the x-axis and slice number from the vertex to the basal parts of the brain on the y-axis. This new image was scaled to a 64 × 16 pixel matrix by interpolation, which meant a normalization of all studies to the same size. The parametric image in each subject was scaled with regard to intensity by a factor calculated by a normalization procedure using the least squares analysis. Mean and SD for each pixel were calculated, thereby constructing a 'mean parametric image', and a 'SD parametric image'. These two images are meant to be used as the reference brain for evaluation of patient studies. This method can be used for objective measurements of diffuse brain changes and for pattern recognition in larger groups of patients. Statistical multifactorial analysis of parameters used for acquisition and data processing is possible. © 2004 Blackwell Publishing Ltd.

  • 34.
    Ruggiero, Martino
    et al.
    DEIS University of Bologna, Italy.
    Gioia, Pari
    DEIS University of Bologna, Italy.
    Alessio, Guerri
    DEIS University of Bologna, Italy.
    Benini, Luca
    DEIS University of Bologna, Italy.
    Michela, Milano
    DEIS University of Bologna, Italy.
    Bertozzi, Davide
    ENDIF University of Ferrara, Italy.
    Andrei, Alexandru
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    A Cooperative, Accurate Solving Framework for Optimal Allocation, Scheduling and Frequency Selection on Energy-Efficient MPSoCs2006In: Intl. Symposium on System-on-Chip SOC06,2006, 2006Conference paper (Refereed)
    Abstract [en]

    Most problems addressed by the software optimization flow for multi-processor systems-on-chip (MPSoCs) are NP-complete, and have been traditionally tackled by means of heuristics and highlevel approximations. Complete approaches have been effectively deployed only under unrealistic simplifying assumptions. We propose a novel methodology to formulate and solve to optimality the allocation, scheduling and discrete voltage selection problem for variable voltage/frequency MPSoCs, minimizing the system energy dissipation and the overhead for frequency switching. We integrate the optimization and validation steps to increase the accuracy of cost models and the confidence in quality of results. Two demonstrators are used to show the viability of the proposed methodology.

  • 35.
    Andersson, Håkan
    et al.
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering. Construct Tools PC AB, Sweden.
    Nordin, Peter
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Borrvall, Thomas
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Simonsson, Kjell
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Hilding, Daniel
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Schill, Mikael
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    A co-simulation method for system-level simulation of fluid-structure couplings in hydraulic percussion units2017In: Engineering with Computers, ISSN 0177-0667, E-ISSN 1435-5663, Vol. 33, no 2, 317-333 p.Article in journal (Refereed)
    Abstract [en]

    This paper addresses a co-simulation method for fluid power driven machinery equipment, i.e. oil hydraulic machinery. In these types of machinery, the fluid-structure interaction affects the end-product performance to a large extent, hence an efficient co-simulation method is of high importance. The proposed method is based on a 1D system model representing the fluid components of the hydraulic machinery, within which structural 3D Finite Element (FE) models can be incorporated for detailed simulation of specific sub-models or complete structural assemblies. This means that the fluid system simulation will get a more accurate structural response, and that the structural simulation will get more correct fluid loads at every time step, compared to decoupled analysis. Global system parameters such as fluid flow, performance and efficiency can be evaluated from the 1D system model simulation results. From the 3D FE-models, it is possible to evaluate displacements, stresses and strains to be used in stress analysis, fatigue evaluation, acoustic analysis, etc. The method has been implemented using two well-known simulation tools for fluid power system simulations and FE-simulations, respectively, where the interface between the tools is realised by use of the Functional Mock-up Interface standard. A simple but relevant model is used to validate the method.

  • 36.
    Öberg, Per
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    A DAE Formulation for Multi-Zone Thermodynamic Models and its Application to CVCP Engines2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the automotive area there are ever increasing demands from legislators and customers on low emissions and good fuel economy. In the process of developing and investigating new technologies, that can meet these demands, modeling and simulation have become important as standard engineering tools. To improve the modeling process new concepts and tools are also being developed.

    A formulation of a differential algebraic equation (DAE) that can be used for simulation of multi-zone in-cylinder models is extended and analyzed. Special emphasis is placed on the separation between thermodynamic state equations and the thermodynamic properties. This enables implementations with easy reuse of model components and analysis of simulation results in a structured manner which gives the possibility to use the formulation in a large number of applications. The introduction and depletion of zones are handled and it is shown that the DAE formulation has a unique solution as long as the gas model fulfills a number of basic criteria. Further, an example setup is used to validate that energy, mass, and volume are preserved when using the formulation in computer simulations. In other words, the numerical solution obeys the thermodynamic state equation and the first law of thermodynamics, and the results are consistent and converge as tolerances are tightened. As example applications, the DAE formulation is used to simulate spark ignited SI and Diesel engines as well as simple control volumes and 1-dimensional pipes. It is thus shown that the DAE formulation is able to adapt to the different requirements of the SI and Diesel engine models.

    An interesting application is the SI engine with continuously variable cam phasing (CVCP), which is a technology that reduces the fuel consumption. It influences the amount of air and residual gases in the engine in a non trivial manner and this SI application is used to evaluate three control oriented models for cylinder air charge and residual mass fraction for a CVCP-engine both for static and transient conditions. The models are: a simple generalized flow restriction model created with physical insight and two variants of a model that is based on an energy balance at intake valve closing (IVC). The two latter models require measurement of cylinder pressure and one also requires an air mass flow measurement. Using the SI model as reference it is shown that transients in cam positions have a large impact on air charge and residual mass fraction, and the ability of the models to capture these effects is evaluated. The main advantages of the generalized flow restriction model are that it is simple and does not require measurement of the cylinder pressure but it is also the model with the largest errors for static operating points and highest sensitivity in transients. The two models that use an energy balance at IVC both handle the transient cycles well. They are, however, sensitive to the temperature at IVC. For static cycles it is therefore advantageous to use the model with air mass flow measurement since it is less sensitive to input data. During transients however, if the external measurement is delayed, it is better to use the model that does not require the air mass flow.

    The conclusion is that the DAE formulation is a flexible, robust, tool, and that it is well suited for multi-zone in-cylinder models as well as models for manifolds and pipes outside the cylinder.

    List of papers
    1. Control Oriented Modeling of the Gas Exchange Process in Variable Cam Timing Engines
    Open this publication in new window or tab >>Control Oriented Modeling of the Gas Exchange Process in Variable Cam Timing Engines
    2006 (English)In: SAE Technical Paper 2006-01-0660, SAE , 2006Conference paper, Published paper (Refereed)
    Abstract [en]

    Variable cam timing engines pose new questions for engine control system designers. The cam timing directly influences cylinder air charge and residual mass fraction. Three models that predict residual mass fraction are investigated for a turbocharged dual independent Variable Cam Timing (VCT) engine. The three models (Fox et. al. 1993, Ponti et. al. 2002, and Mladek et. al. 2000) that all have real time capabilities are evaluated and validated against data from a crank angle based reference model. None of these models have previously been validated to cover this engine type. It is shown that all three models can be extended to dual independent VCT engines and that they also give a good description of the residual gas fraction. However, it is shown that the two most advanced models, based on a thermodynamic energy balance, are very sensitive to the model inputs and proper care must therefore be taken when these models are used

    Place, publisher, year, edition, pages
    SAE, 2006
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-18306 (URN)
    Available from: 2009-05-18 Created: 2009-05-18 Last updated: 2009-10-14Bibliographically approved
    2. Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity
    Open this publication in new window or tab >>Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity
    2007 (English)In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 62, no 4, 573-584 p.Article in journal (Refereed) Published
    Abstract [en]

    The paper analyzes a set of control oriented models for the gas exchange phase in engines with continuously variable cam phasing (CVCP). These models describe the mass flow of fresh gases and the residual gases caught in the cylinder during the gas exchange phase. Simulations with CVCP transients are also performed to analyze the models performance during transients.

    Place, publisher, year, edition, pages
    IFP, 2007
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-18307 (URN)10.2516/ogst:2007041 (DOI)
    Available from: 2009-05-18 Created: 2009-05-18 Last updated: 2017-12-13Bibliographically approved
  • 37.
    Svärd, Carl
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nyberg, Mattias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Frisk, Erik
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Krysander, Mattias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    A Data-Driven and Probabilistic Approach to Residual Evaluation for Fault Diagnosis2011In: 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC), 2011, Institute of Electrical and Electronics Engineers (IEEE), 2011, 95-102 p.Conference paper (Refereed)
    Abstract [en]

    An important step in fault detection and isolation is residual evaluation where residuals, signals ideally zero in the no-fault case, are evaluated with the aim to detect changes in their behavior caused by faults. Generally, residuals deviate from zero even in the no-fault case and their probability distributions exhibit non-stationary features due to, e.g., modeling errors, measurement noise, and different operating conditions. To handle these issues, this paper proposes a data-driven approach to residual evaluation based on an explicit comparison of the residual distribution estimated on-line and a no-fault distribution, estimated off-line using training data. The comparison is done within the framework of statistical hypothesis testing. With the Generalized Likelihood Ratio test statistic as starting point, a more powerful and computational efficient test statistic is derived by a properly chosen approximation to one of the emerging likelihood maximization problems. The proposed approach is evaluated with measurement data on a residual for diagnosis of the gas-flow system of a Scania truck diesel engine. The proposed test statistic performs well, small faults can for example be reliable detected in cases where regular methods based on constant thresholding fail.

  • 38.
    Nilsson, Marcus
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Westring, Alexander
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A decision support system for an improved article placement2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Warehouse storage is an important part of a business’ supply chain. This is where articles temporary are stored before they either are carried on to the next step of the production or to be delivered to the customers of the company. The largest part of the stock keeping often devoted to the order picking. Order picking includes the activities that are occurring when an article is being picked from its stored position and is being transported to the next step of the flow of the materials. The most time- consuming part of the order picking process are often the time to pinpoint and to get the hold of an article. This implies quite likely that an enhancement of the productivity could be realized, inter alia, through cut the transport distances. SKF Mekan AB is an industrial corporation whose primary occupation is to manufacture bearing housings. Currently, the business has a flawed inventory for stock keeping. A great many of the articles stored in the inventory, entitled 104C, are placed in regard to their measures, without any thought in regard of how frequently the articles are picked. In addition, the article placement that is used today is outdated, which has resulted in that a lot of articles are lacking a specific placement in the inventory. The purpose of storing articles in the inventory 104C is to cope with fluctuations in the next step of the manufacturing, which is the processing factory. The aim of the study is to find out how the article placement looks in the current situation and how decisions concerning article placement are determined and what issues occurs due to this. A decision support system has been developed which purpose is to give SKF Mekan AB decision basis regarding where the different kinds of articles should be placed to attain an increased efficiency in business’ stock keeping. The decision support system is adaptable to the extent that the user can adjust the parameters that are determining the article placement. The study has been accomplished by means of observations and interviews. With the help of the observations, the layout of the warehouse and the article placement has been mapped out and with the help of the interviews; the results concerning work models and decision-making of article placement has been answered. Through the observations and the interviews appeared that 42.5 % of the stocked pallets were misplaced and that 15.6 % of the stocked pallets lacked a specific placement in the warehouse. This results in that the truck operators has a hard time localizing the pallets, which leads to inefficient labouring. This causes delays in the next step of the supply chain; i. e. the processing factory, meaning the personnel has to wait for the articles to be delivered. With the articles picking frequency and the principle of family grouping as point of reference for the article placement SKF Mekan AB should be able to eliminate non-value adding activities in the supply chain, which should lead to an increased potential of profitability.

  • 39.
    Levén, Pernilla
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Mohn, Henrik
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    A Diversity Perspective on Knowledge Transfer at Nordic Trading Floors: Does wearing suits and playing golf help the employees to learn?2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: This thesis is about knowledge transfer and diversity at Nordic trading floors. The research is focusing on knowledge transfer and how it is influenced by diversity and the ties between homogenous people.

    Purpose: The purpose of this study is to understand how the knowledge transfer could be more efficient at Nordic trading floors and whether employees prefer to share knowledge with employees to whom they either have a weak or strong social tie to. We also want to see how homogenous people impact the flow of knowledge transfer.

    Methodology: This research is conducted through a case study of respondents working at trading floors at two different banks in the Nordic countries. The data is mainly collected through quantitative surveys and qualitative interviews.

    Conclusions: Knowledge transfer at Nordic trading floors is implemented through different types of training and mentoring and by keeping up with strong social ties which is feeding the sociocultural arena. Homogenous people are contributing to knowledge transfer by spreading tacit knowledge while networking and socializing with each other. Wearing suits and playing golf might therefore help employees at Nordic trading floors to learn more.

  • 40.
    Hägglöf, Kristoffer
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Lindberg, Per Olov
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A dual algorithm for the convex multicommodity flow problemManuscript (preprint) (Other academic)
    Abstract [en]

    This paper introduces a new dual ascent algorithm for solving the convex multicommodity flow problem, CMFP for short. CMFPs arize in many different routing problems such as the design of packet switched computer networks and the computation of traffic network equilibria. The algorithm utilizes the structure of the dual convex multicommodity flow problem, DCMFP for short. The dual objective is a sum of a concave differentiable function and a piecewise linear concave function. The algorithm exploits the local structure of the dual objective in an ascent scheme. In this paper a thorough explanation of the CMFPs and DCMFPs are given along with an outline of the dual ascent algorithm proposed. The method are applied to CMFPs arizing in the traffic assignment setting.

  • 41.
    Burdakov, Oleg
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Holmberg, Kaj
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Olsson, Per-Magnus
    Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab. Linköping University, The Institute of Technology.
    A Dual Ascent Method for the Hop-constrained Shortest Path with Application to Positioning of Unmanned Aerial Vehicles2008Report (Other academic)
    Abstract [en]

    We study the problem of positioning unmanned aerial vehicles (UAVs) to maintain an unobstructed flow of communication from a surveying UAV to some base station through the use of multiple relay UAVs. This problem can be modeled as a hopconstrained shortest path problem in a large visibility graph. We propose a dual ascent method for solving this problem, optionally within a branch-and-bound framework. Computational tests show that realistic problems can be solved in a reasonably short time, and that the proposed method is faster than the classical dynamic programming approach.

  • 42.
    Amankwah, Henry
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Textorius, Björn
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    A Duality-Based Derivation of the Maximum Flow Formulation of the Open-Pit Design ProblemManuscript (preprint) (Other academic)
    Abstract [en]

    Open-pit mining is a surface mining operation whereby ore, or waste, is excavated from the surface of the land. The open-pit design problem is deciding on which blocks of an ore deposit to mine in order to maximize the total profit, while obeying digging constraints concerning pit slope and block precedence. The open-pit design problem can be formulated as a maximum flow problem in a certain capacitated network, as first shown by Picard in 1976. His derivation is based on a restatement of the problem as a quadratic binary program. We give an alternative derivation of the maximum flow formulation, which uses only linear programming duality.

  • 43. Vassiljev, A
    et al.
    Grimvall, Anders
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Mathematics, Statistics .
    Larsson, M
    A dual-porosity model for nitrogen leaching from a watershed2004In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 49, no 2, 313-322 p.Article in journal (Refereed)
    Abstract [en]

    The MASONW (MACRO + SOILN + Watershed) model describing nitrogen leaching in watersheds was developed and tested. The model is based on the MACRO and SOILN models. The dual-porosity model MACRO simulates water flow on the field scale. The SOILN model describes turnover and leaching of nitrogen. Two main features of a watershed have been added into these two models: (a) the existence of a river system, and (b) variable thickness of the aeration zone within a watershed. Good agreement between the output of the MASONW model and observed data for water discharge and nitrate concentrations were achieved in the Odense watershed (496 km2) in Denmark.

  • 44.
    Palmkvist, Kent
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Nordhamn, Erik
    n/a.
    Wanhammar, Lars
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A fast bit-serial lattice wave digital filter1992In: Proc. NUTEK Workshop on Digital Communications, 1992, 88-92 p.Conference paper (Other academic)
    Abstract [en]

    In this paper we discuss the implementation of maximally fast fixed-function digital filters. We demonstrate by means of an example that digital filters with sampling frequencies of more than hundred MHz can efficiently be implemented by using bit-serial PEs. The proposed approach lead to maximally fast filters that require little chip area and have low power consumption. Further, we show that the iteration period bound by Renfors et al. often can be lowered by applying equivalence transformations to the signal-flow graph.

  • 45.
    Nordberg, Klas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Computer Vision.
    Doherty, Patrick
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    Forssén, Per-Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Computer Vision.
    Wiklund, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Computer Vision.
    Andersson, Per
    A flexible runtime system for image processing in a distributed computational environment for an unmanned aerial vehicle2006In: International Journal of Pattern Recognition and Artificial Intelligence, ISSN 0218-0014, Vol. 20, no 5, 763-780 p.Article in journal (Refereed)
    Abstract [en]

    A runtime system for implementation of image processing operations is presented. It is designed for working in a flexible and distributed environment related to the software architecture of a newly developed UAV system. The software architecture can be characterized at a coarse scale as a layered system, with a deliberative layer at the top, a reactive layer in the middle, and a processing layer at the bottom. At a finer scale each of the three levels is decomposed into sets of modules which communicate using CORBA, allowing system development and deployment on the UAV to be made in a highly flexible way. Image processing takes place in a dedicated module located in the process layer, and is the main focus of the paper. This module has been designed as a runtime system for data flow graphs, allowing various processing operations to be created online and on demand by the higher levels of the system. The runtime system is implemented in Java, which allows development and deployment to be made on a wide range of hardware/software configurations. Optimizations for particular hardware platforms have been made using Java's native interface.

  • 46.
    Axin, Mikael
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    Eriksson, Björn
    Parker Hannifin, Borås, Sweden.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    A Flexible Working Hydraulic System for Mobile Machines2016In: International Journal of Fluid Power, ISSN 1439-9776, Vol. 17, no 2, 79-89 p.Article in journal (Other academic)
    Abstract [en]

    This paper proposes a novel working hydraulic system architecture for mobile machines. Load sensing, flow control and open-centre are merged into a generalized system description. The proposed system is configurable and the operator can realize the characteristics of any of the standard systems without compromising energy efficiency. This can be done non-discretely on-the-fly. One electrically controlled variable displacement pump supplies the system and conventional closed-centre spool valves are used. The pump control strategies are explained in detail. Experimental results demonstrate one solution to the flow matching problem and the static and dynamic differences between different control modes.

  • 47.
    Ramström, A Sofia
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Fagerberg, I.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    A flow cytometric assay for the study of dense granule storage and release in human platelets1999In: Platelets, ISSN 0953-7104, E-ISSN 1369-1635, Vol. 10, no 2-3, 153-158 p.Article in journal (Refereed)
    Abstract [en]

    The clinical manifestations of platelet dense (δ) granule defects are easy bruising, as well as epistaxis and bleeding after delivery, tooth extractions and surgical procedures. The observed symptoms may be explained either by a decreased number of granules or by a defect in the uptake/release of granule contents. We have developed a method to study platelet dense granule storage and release. The uptake of the fluorescent marker, mepacrine, into the platelet dense granule was measured using flow cytometry. The platelet population was identified by the size and binding of a phycoerythrin-conjugated antibody against GPIb. Cells within the discrimination frame were analysed for green (mepacrine) fluorescence. Both resting platelets and platelets previously stimulated with collagen and the thrombin receptor agonist peptide SFLLRN was analysed for mepacrine uptake. By subtracting the value for mepacrine uptake after stimulation from the value for uptake without stimulation for each individual, the platelet dense granule release capacity could be estimated. Whole blood samples from 22 healthy individuals were analysed. Mepacrine incubation without previous stimulation gave mean fluorescence intensity (MFI) values of 83±6 (mean ± 1 SD, range 69–91). The difference in MFI between resting and stimulated platelets was 28±7 (range 17–40). Six members of a family, of whom one had a known δ-storage pool disease, were analysed. The two members (mother and son) who had prolonged bleeding times also had MFI values disparate from the normal population in this analysis. The values of one daughter with mild bleeding problems but a normal bleeding time were in the lower part of the reference interval.

  • 48.
    Gutes, A.
    et al.
    Gutés, A., Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    Cespedes, F.
    Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    del, Valle M.
    del Valle, M., Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    Louthander, D.
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    A flow injection voltammetric electronic tongue applied to paper mill industrial waters2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 115, no 1, 390-395 p.Article in journal (Refereed)
    Abstract [en]

    A voltammetric electronic tongue with automated operation based on the flow injection (FIA) technique was applied to the characterization of wastewaters coming from the paper mill industry. A metallic multielectrode array - formed by platinum, gold and rhodium electrodes - was employed as the detection system, while the measurements were based on large amplitude pulse voltammetry (LAPV). LAPV consisted in scans of pulses from to 0 to 1.8 V at 0.2 V steps. Five current values were recorded for each pulse, so a set of 300 current values (three electrodes × 20 pulses × five values) was recorded for each sample. Samples were first discriminated using Principal Component Analysis (PCA), while Artificial Neural Networks were used for the characterization and prediction of chemical oxygen demand, conductivity and pH. The system may be used for the quick identification and monitoring of the quality of used waters in these industrial facilities. © 2005 Elsevier B.V. All rights reserved.

  • 49.
    Törnå, Jonas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A flow mapping of asphalt works2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpos of this study i to examin how the flow apperars as two different machine working team at Skanska coating in Norrköping. its also to explore possible improvements and benefits there are to extract. And investigate how the actions can activity in a constand development and increasing production effiency.

    The report is divided into three parts. part one deals with a background desciption of skanska, and explantion of potential benefits. after follows the section where and discussion section. the eassy completes with an analysis and discussion section. the discussion and analysis are based with an result from the study section.

  • 50.
    Olsson, John
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    A Flow System for Urea and Glucose Measurement with a Self Polishing Electronic TongueManuscript (preprint) (Other academic)
    Abstract [en]

    A self polishing voltammetric electronic tongue was evaluated for simultaneousl prediction of urea and glucose concentrations in phosphate buffer in a flow system. The voltammetric electronic tongue consisted of three working electrodes (gold, platinum and rhodium) and a counter electrode, also acting as reference electrode. The flowsystem contained five valves, controlled by a computer and a peristaltic pump. Two batches of sample standards were used; one for calibration and the other for validation. The system could predict concentrations of urea and glucose in the interval 0 – 20 mM in the validation batch. No significant difference between the two batches was seen. The self polishing approach makes the system in principle maintenance free. With a large potential use in hemodialysis.

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