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  • 1051.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Monitorering av andning and blodtrycksförändringar baserat på EKG och hjärtljud2007In: Medicinteknik dagarna,2007, 2007Conference paper (Other academic)
  • 1052.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Noninvasive investigation of blood pressure changes using the pulse wave transit time: A novel approach in the monitoring of hemodialysis patients2005In: Journal of Artificial Organs, ISSN 1434-7229, E-ISSN 1619-0904, Vol. 8, no 3, p. 192-197Article in journal (Refereed)
    Abstract [en]

    Severe blood pressure changes are well known in hemodialysis. Detection and prediction of these are important for the well-being of the patient and for optimizing treatment. New noninvasive methods for this purpose are required. The pulse wave transit time technique is an indirect estimation of blood pressure, and our intention is to investigate whether this technique is applicable for hemodialysis treatment. A measurement setup utilizing lower body negative pressure and isometric contraction was used to simulate dialysis-related blood pressure changes in normal test subjects. Systolic blood pressure levels were compared to different pulse wave transit times, including and excluding the cardiac preejection period. Based on the results of these investigations, a pulse wave transit time technique adapted for dialysis treatment was developed and tried out on patients. To determine systolic blood pressure in the normal group, the total pulse wave transit time was found most suitable (including the cardiac preejection period). Correlation coefficients were r = 0.80 ± 0.06 (mean ± SD) overall and r = 0.81 ± 0.16 and r = 0.09 ± 0.62 for the hypotension and hypertension phases, respectively. When applying the adapted technique in dialysis patients, large blood pressure variations could easily be detected when present. Pulse wave transit time is correlated to systolic blood pressure within the acceptable range for a trend-indicating system. The method's applicability for dialysis treatment requires further studies. The results indicate that large sudden pressure drops, like those seen in sudden hypovolemia, can be detected. © The Japanese Society for Artificial Organs 2005.

  • 1053.
    Ahlström, Christer
    et al.
    Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Kircher, Katja
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences. Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    A Generalized Method to Extract Visual Time-Sharing Sequences From Naturalistic Driving Data2017In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 18, no 11, p. 2929-2938Article in journal (Refereed)
    Abstract [en]

    Indicators based on visual time-sharing have been used to investigate drivers visual behaviour during additional task execution. However, visual time-sharing analyses have been restricted to additional tasks with well-defined temporal start and end points and a dedicated visual target area. We introduce a method to automatically extract visual time-sharing sequences directly from eye tracking data. This facilitates investigations of systems, providing continuous information without well-defined start and end points. Furthermore, it becomes possible to investigate time-sharing behavior with other types of glance targets such as the mirrors. Time-sharing sequences are here extracted based on between-glance durations. If glances to a particular target are separated by less than a time-based threshold value, we assume that they belong to the same information intake event. Our results indicate that a 4-s threshold is appropriate. Examples derived from 12 drivers (about 100 hours of eye tracking data), collected in an on-road investigation of an in-vehicle information system, are provided to illustrate sequence-based analyses. This includes the possibility to investigate human-machine interface designs based on the number of glances in the extracted sequences, and to increase the legibility of transition matrices by deriving them from time-sharing sequences instead of single glances. More object-oriented glance behavior analyses, based on additional sensor and information fusion, are identified as the next future step. This would enable automated extraction of time-sharing sequences not only for targets fixed in the vehicles coordinate system, but also for environmental and traffic targets that move independently of the drivers vehicle.

  • 1054.
    Ahlström, Christer
    et al.
    Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Kircher, Katja
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences. Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Changes in glance behaviour when using a visual eco-driving system - A field study2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 58, p. 414-423Article in journal (Refereed)
    Abstract [en]

    While in-vehicle eco-driving support systems have the potential to reduce greenhouse gas emissions and save fuel, they may also distract drivers, especially if the system makes use of a visual interface. The objective of this study is to investigate the visual behaviour of drivers interacting with such a system, implemented on a five-inch screen mounted above the middle console. Ten drivers participated in a real world, on-road driving study where they drove a route nine times (2 pre-baseline drives, 5 treatment drives, 2 post-baseline drives). The route was 96 km long and consisted of rural roads, urban roads and a dual-lane motorway. The results show that drivers look at the system for 5-8% of the time, depending on road type, with a glance duration of about 0.6 s, and with 0.05% long glances (amp;gt;2s) per kilometre. These figures are comparable to what was found for glances to the speedometer in this study. Glance behaviour away from the windscreen is slightly increased in treatment as compared to pre- and post-baseline, mirror glances decreased in treatment and post-baseline compared to pre-baseline, and speedometer glances increased compared to pre-baseline. The eco-driving support system provided continuous information interspersed with additional advice pop-ups (announced by a beep) and feedback pop-ups (no auditory cue). About 20% of sound initiated advice pop-ups were disregarded, and the remaining cases were usually looked at within the first two seconds. About 40% of the feedback pop-ups were disregarded. The amount of glances to the system immediately before the onset of a pop-up was clearly higher for feedback than for advice. All in all, the eco-driving support system under investigation is not likely to have a strong negative impact on glance behaviour. However, there is room for improvements. We recommend that eco-driving information is integrated with the speedometer, that optional activation of sound alerts for intermittent information is made available, and that the pop-up duration should be extended to facilitate self-regulation of information intake. (C) 2016 Elsevier Ltd. All rights reserved.

  • 1055.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Kircher, Albert
    Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    A Gaze-Based Driver Distraction Warning System and Its Effect on Visual Behavior2013In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 14, no 2, p. 965-973Article in journal (Refereed)
    Abstract [en]

    Driver distraction is a contributing factor to many crashes; therefore, a real-time distraction warning system should have the potential to mitigate or circumvent many of these crashes. The objective of this paper is to investigate the usefulness of a real-time distraction detection algorithm called AttenD. The evaluation is based on data from an extended field study comprising seven drivers who drove on an average of 4351 +/- 2181 km in a naturalistic setting. Visual behavior was investigated both on a global scale and on a local scale in the surroundings of each warning. An increase in the percentage of glances at the rear-view mirror and a decrease in the amount of glances at the center console were found. The results also show that visual time sharing decreased in duration from 9.94 to 9.20 s due to the warnings, that the time from fully attentive to warning decreased from 3.20 to 3.03 s, and that the time from warning to full attentiveness decreased from 6.02 to 5.46 s. The limited number of participants does not allow any generalizable conclusions, but a trend toward improved visual behavior could be observed. This is a promising start for further improvements of the algorithm and the warning strategy.

  • 1056.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering.
    Liljefeldt, Olle
    Hult, Peter
    Linköping University, Department of Biomedical Engineering.
    Ask, Per
    Linköping University, Department of Biomedical Engineering.
    Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction.2005In: Medicinteknikdagarna, 2005, Vol. 12, p. 812-815Conference paper (Other academic)
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0 34 0 25, 0 50 0 33, 0 46 0 35, and 0 94 0 64 dB/Hz in the frequency bands 20–40, 40–70, 70–150, and 150–300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

  • 1057.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Liljefeldt, Olle
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction2005In: IEEE Signal Processing Letters, ISSN 1070-9908, E-ISSN 1558-2361, Vol. 12, no 12, p. 812-815Article in journal (Refereed)
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0.34/spl plusmn/0.25, 0.50/spl plusmn/0.33, 0.46/spl plusmn/0.35, and 0.94/spl plusmn/0.64 dB/Hz in the frequency bands 20-40, 40-70, 70-150, and 150-300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

  • 1058.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Johansson, Anders
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    A method for accurate localization of the first heart sound and possible applications2008In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 29, no 3, p. 417-428Article in journal (Refereed)
    Abstract [en]

    We have previously developed a method for localization of the first heart sound (S1) using wavelet denoising and ECG-gated peak-picking. In this study, an additional enhancement step based on cross-correlation and ECG-gated ensemble averaging (EA) is presented. The main objective of the improved method was to localize S1 with very high temporal accuracy in (pseudo-) real time. The performance of S1 detection and localization, with and without EA enhancement, was evaluated on simulated as well as experimental data. The simulation study showed that EA enhancement reduced the localization error considerably and that S1 could be accurately localized at much lower signal-to-noise ratios. The experimental data were taken from ten healthy subjects at rest and during invoked hyper- and hypotension. For this material, the number of correct S1 detections increased from 91% to 98% when using EA enhancement. Improved performance was also demonstrated when EA enhancement was used for continuous tracking of blood pressure changes and for respiration monitoring via the electromechanical activation time. These are two typical applications where accurate localization of S1 is essential for the results.

  • 1059.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nystrom, Marcus
    Lund University, Sweden .
    Holmqvist, Kenneth
    Lund University, Sweden .
    Fors, Carina
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Sandberg, David
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Anund, Anna
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Kecklund, Goran
    Stockholm University, Sweden .
    Akerstedt, Torbjorn
    Stockholm University, Sweden .
    Fit-for-duty test for estimation of drivers sleepiness level: Eye movements improve the sleep/wake predictor2013In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 26, p. 20-32Article in journal (Refereed)
    Abstract [en]

    Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a drivers sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R = 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS andgt;= 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers.

  • 1060.
    Ahlström, Daniel
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Minimizing memory requirements for deterministic test data in embedded testing2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Embedded and automated tests reduce maintenance costs for embedded systems installed in remote locations. Testing multiple components of an embedded system, connected on a scan chain, using deterministic test patterns stored in a system provide high fault coverage but require large system memory. This thesis presents an approach to reduce test data memory requirements by the use of a test controller program, utilizing the observation of that there are multiple components of the same type in a system. The program use deterministic test patterns specific to every component type, which is stored in system memory, to create fully defined test patterns when needed. By storing deterministic test patterns specific to every component type, the program can use the test patterns for multiple tests and several times within the same test. The program also has the ability to test parts of a system without affecting the normal functional operation of the rest of the components in the system and without an increase of test data memory requirements. Two experiments were conducted to determine how much test data memory requirements are reduced using the approach presented in this thesis. The results for the experiments show up to 26.4% reduction of test data memory requirements for ITC´02 SOC test benchmarks and in average 60% reduction of test data memory requirements for designs generated to gain statistical data.

  • 1061.
    Ahlström, Gerd
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nursing Science.
    Carlsson, C
    Att visa upp sin värld: Hur personer med stora varaktiga funktionshinder uppfattar sin livssituation relaterat till de etiska principerna i LSS2002Report (Other academic)
  • 1062.
    Ahlström, Gerd
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nursing Science.
    Wennberg, S
    Coping with illness-related problems in persons with progressive muscular diseases: the Swedish version of the Ways of Coping Questionnaire2002In: Scandinavian Journal of Caring Sciences, ISSN 0283-9318, E-ISSN 1471-6712, Vol. 16, p. 368-375Article in journal (Refereed)
  • 1063. Ahlström, H.
    et al.
    Johansson, L.
    Smedby, Örjan
    Uppsala University.
    Magnusson, A.
    Raland, H.
    Wahlberg, J.
    Computed Tomography Angiography (CTA) and Magnetic Resonance Angiography (MRA) in the diagnosis of renal transplant artery stenosis1996Conference paper (Refereed)
  • 1064. Ahlström, H.
    et al.
    Smedby, Örjan
    Uppsala University.
    Löfberg, AM.
    Bergkvist, D.
    Ljungman, C.
    Magnetic Resonance Angiography of Peripheral Run-off Vessels1995Conference paper (Other academic)
  • 1065.
    Ahlström, Hanna
    Linköping University, Department of Educational Science (IUV).
    Barn med Asperger syndrom2003Independent thesis Basic level (professional degree)Student thesis
    Abstract [sv]

    Det här examensarbetet handlar om barn med Asperger syndrom. Syftet med arbetet var att ta reda på vad Asperger syndrom är och hur man som lärare kan hjälpa dessa elever på bästa sätt. Jag är intresserad av elever som har det svårt och antar att jag någon gång under min tid som lärare kommer att stöta på dessa elever.

    Arbetet inleds med en teorigenomgång där jag främst går igenom de utmärkande dragen hos barn med Asperger syndrom. Där går jag också bl a igenom orsaker till Asperger och diagnostisering. Andra delen av arbetet är praktiska råd till lärare som arbetar med elever som har Asperger syndrom, vad läraren bör tänka på. Skolans främsta uppgifter, hur klassrummet bör se ut och arbetsmetoder är saker som jag går igenom där.

    Det som jag kommer fram till där är att det är mycket viktigt med struktur och ordning. Alla barn mår bra av att veta hur dagen ser ut, men för barn med Asperger så är det mycket viktigt att dagen följer vissa rutiner. För att barnen ska kunna ha det så bra som möjligt så är det bra att ha mål utsatta för eleven, både kortsiktiga och långsiktiga. Det är också viktigt med ett personligt dagsschema, så eleven vet vad som kommer att hända under dagen.

  • 1066.
    Ahlström, Henrik
    et al.
    Linköping University, Department of Science and Technology.
    Skoglund, Karl-Johan
    Linköping University, Department of Science and Technology.
    Encryption in Delocalized Access Systems2008Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    The recent increase in performance of embedded processors has enabled the use of computationally heavy asymmetric cryptography in small and power efficient embedded systems. The goal of this thesis is to analyze whether it is possible to use this type of cryptography to enhance the security in access systems.

    This report contains a literature study of the complications related to access systems and their functionality. Also a basic introduction to cryptography is included.

    Several cryptographic algorithms were implemented using the public library LibTomCrypt and benchmarked on an ARM7-processor platform. The asymmetric coding schemes were ECC and RSA. The tested symmetric algorithms included AES, 3DES and Twofish among others. The benchmark considered both codesize and speed of the algorithms.

    The two asymmetric algorithms, ECC and RSA, are possible to be used in an ARM7 based access system. Although, both technologies can be configured to finish the calculations within a reasonable time-frame of 10 Sec, ECC archives a higher security level for the same execution time. Therefore, an implementation of ECC would be preferable since it is faster and requires less resources. Some further suggestions of improvements to the implementation is discussed in the final chapters.

  • 1067.
    Ahlström, Jenni
    et al.
    Linköping University, Department of Management and Economics.
    Larsson, Lina
    Linköping University, Department of Management and Economics.
    Konsten att belöna goda prestationer: en studie i projektorienterad miljö2002Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [sv]

    Bakgrund: I de kunskapsintensiva företagen av idag krävs en ny utformning av belöningssystem. Eftersom de mänskliga resurserna utgör en viktig del i konkurrenskraften är det också alla medarbetare i företaget som ska beröras av ett belöningssystem. Utmaningen ligger i att företagets övergripande målsättning med belöningssystemet måste fogas samman med medarbetarnas uppfattning om vad som motiverar för att det ska få avsedd effekt.

    Syfte: Syftet med uppsatsen är att analysera utformningen av belöningssystem i en komplex projektorienterad miljö, med hänsyn tagen till såväl företagsledningens önskemål om beteenden och prestationer att premiera som till vilka belöningar sommotiverar medarbetarna.

    Genomförande: Intervjuer har genomförts med 7 chefer och 8 medarbetare på ABB Power Systems. Dessutom har en enkätundersökning bland medarbetare inom enheten genomförts.

    Resultat: Studien visar att önskvärda prestationer och beteenden kan specificeras i måluppfyllelse respektive goda insatser. I en projektorienterad miljö bör det finnas utrymme för att belöna såväl enskilda individer som grupper. Belöningar som utdelas ska variera både i förhållande till vad de består av och med avseende på deras värde.

  • 1068.
    Ahlström, Johannes
    Linköping University, Department of Computer and Information Science.
    Permutationer av omskrivningsregler: Egenskaper hos omskrivningsregler till lättläst svenska2013Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [sv]

    Studien ar en analysering av omskrivningsregler framtagna av Decker (2003), dessa omskrivningsregler har implementerats i ett verktyg som heter CogFLUX. Syftet med dessa omskrivningsregler ar att forenkla det svenska spraket och gora det mer lattlast. CogFLUX tar en given text som input och omskrivningsregler valjs ut och appliceras pa texterna med hjalp av verktyget. Detta verktyg returnerar sedan en omskriven text och de tre olika lasbarhetsmatten LIX, OVIX och NR for texten. Syftet med studien har varit att se huruvida olika permutationer av en given uppsattning omskrivningsregler ger olika resultat matt med lasbarhetsmatten samt om det finns kombinationer av omskrivningsregler som fungerar battre an andra. Utvardering har skett pa tre olika texttyper pa vardera ca 5000 ord. Resultaten har visat att olika permutationer av omskrivningsregler inte ger nagon matbar effekt matt med lasbarhetsmatt. Av totalt atta applicerade omskrivningsregler har fyra visat sig vara effektiva och forenkla texter matt med lasbarhetsmatten.

  • 1069.
    Ahlström, Linus
    Linköping University, Department of Electrical Engineering.
    Algoritmer för objektdetektering i SAR och IR-bilder2003Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    The first part of the thesis consists of a brief introduction to the general principles of target detection and the sensor-systems used. In the following part there is a theoretical description of the algorithms this thesis focuses on. The detection algorithms described in this paper are called Cell Average, Ordered Statistics, 2parameter and Gammadetector. Two different discriminators called Extended Fractal Features and Quadratic Gamma Discriminator are also described. The algorithms are tested on three different types of data, simulated SAR-pictures, authentic SAR-targets and IR-pictures. The last part account for the results, both those achieved with pictures and those results achieved when doing statistical tests, in this case MonteCarlo- simulations and Reciever Operating Characteristics-curves. The results show that the Gamma- detector and the QGD-algorithm perform best on the tests done in this thesis.

  • 1070.
    Ahlström, Louise
    et al.
    Linköping University, Department of Management and Economics.
    Hjelm, Caroline
    Linköping University, Department of Management and Economics.
    Ett varumärkets styrka och dess distribution: en studie genomförd med utgångspunkt från varumärken som säljer en livsstil2001Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [en]

    Background: A strong brand is becoming an increasingly important factor when surviving on a competitive market. A strong brand can therefore be considered a strategically important resource. The relationship between a brand's strength and its distribution can decide the future of a brand in the long run. Lifestyle branding is becoming a more popular way of differentiating ones brand from the competition.

    Purpose: The purpose of this thesis is to identify factors which according to the lifestyle brand owners are central when measuring the strength of a brand. Furthermore it will also identify functions of the distribution channel over which the brand owner wishes to have control. The goal is to try to capture these dimensions in a measuring model. The model is aimed at being used by lifestyle brand owners in order to identify a position of the relationship of a brands strength and its distribution.

    Procedure: We chose to conduct a qualitative study and performed five interviews. Our chosen method was one of induction. By combining empirical data with existing theories of brand strength and distribution we have identified factors and functions which according to the brand owner are considered central.

    Results: When evaluating a brands strength the factors which could be considered are quality, recognition, recall, loyalty, and market share. To evaluate the distribution one can consider the control the brand owner has over the following functions of distribution; assortment, exposure, price, and knowledge of the personnel. We conclude that an increase of brand strength will provoke an increase of control over distribution. This relation also works in the opposite direction.

  • 1071.
    Ahlström, Magnus
    et al.
    Saab AB.
    Söderlund, Jonas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Management and Economics, Business Administration.
    Utbildning om och i ett projekt2003In: I teori och praktik, Linköping: CUP, LiUTryck , 2003Chapter in book (Other academic)
  • 1072.
    Ahlström, Martin
    Linköping University, Department of Computer and Information Science.
    User-centred redesign of a business systemusing the Star Life Cycle method2008Independent thesis Advanced level (degree of Master), 20 points / 30 hpStudent thesis
    Abstract [en]

    The purpose with this thesis was to study user activities in a business system, MediusFlow. The overall objective was to identify user related problems and to analyse which of the usability data gathering methods to use in the future development process of the company Medius.

    The outcome of this study indicated that a cognitive related user problem was the most important problem to solve. A Star Life Cycle method was preferred. Two low-fidelity prototypes were developed to exemplify an alternative design solution to the identified cognitive user problem. Furthermore, the two best methods to use when gathering user related requirements were heuristic evaluation and expert review.

    In addition a company specific Style Guide was created with generic guidelines as a foundation for development of future applications within Medius.

  • 1073.
    Ahlström, Mattias
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Development of an Attractive Network for Regional Bus Traffic in Dalarna County2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Även om direktbusstrafiken i Dalarnas län redan i dagsläget trafikerar relativt raka och snabba linjesträckningar anser länstrafikbolaget Dalatrafik att det finns potential till att ytterligare sänka restiderna för att locka fler resenärer. Fyra av länets viktigaste direktbusslinjer har därför studerats och för var och en av dessa har ett antal förändringsåtgärder tagits fram. Målet med förändringsåtgärderna har varit att, i första hand, åstadkomma en rakare linjesträckning och utreda hur mycket restiden skulle komma att förändras om bussen istället kör den nya vägen. Utifrån befintlig resandestatistik över hur många resenärer som reser på varje sträcka har den totala tidsbesparingen för samtliga förändringsåtgärder per linje beräknats och detta har givits ett monetärt värde. Genom täckningsanalyser har befolkningen inom upptagningsområdet kring varje hållplats beräknats, detta för att visa hur tillgängligheten till respektive linje förändras efter ett eventuellt införande av de föreslagna åtgärderna.

  • 1074. Ahlström, Monica
    et al.
    Blomé, Ulrika
    Broqvist, Mari
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Medicine and Health Sciences.
    Göransson, Ingrid
    Nilsson, Anna-Karin
    Pettersson, Ulla
    Ett praktiskt försök: nationell prioriteringsmodell tillämpad i Landstinget i Kalmar Län2008Report (Other academic)
    Abstract [sv]

    Idag finns en nationell modell för hur öppna vertikala prioriteringar kan genomföras. Den är resultatet av de samlade erfarenheterna av att omsätta riksdagens riktlinjer för prioriteringar i praktiskt prioriteringsarbete. Modellen är framtagen av Socialstyrelsen, PrioriteringsCentrum samt flera vårdförbund och landsting gemensamt. Också FSA och LSR har ställt sig bakom den. Fram tills nu har det dock saknats praktisk erfarenhet av att tillämpa modellen inom arbetsterapi och sjukgymnastik. Men sedan drygt två år tillbaka har de båda rehabiliteringsenheterna Samrehab och Rehab Söder i Landstinget i Kalmar län med stöd av PrioriteringsCentrum bedrivit ett prioriteringsarbete i enlighet med modellen. Det är deras erfarenheter denna rapport handlar om.

    Prioriteringsarbetet har med nära stöd av verksamhetsledningarna letts av en projektgrupp bestående av arbetsterapeuter och sjukgymnaster från de båda enheterna som fungerat som handledare, ansvarat för metodutveckling och utbildning samt kontinuerligt utvärderat arbetet. Själva tillämpningen av den nationella modellen har ett antal utvecklingsgrupper inom olika specialistområden stått för. De har valt ut och rangordnat tillstånd och olika åtgärder som de ansett angelägna att ta fram prioriteringar för.

    Ett av syftena med prioriteringsarbetet i Samrehab och Rehab Söder var att få till stånd länsövergripande prioriteringar inom vissa verksamheter och/eller för vissa sjukdomstillstånd för en mer likvärdig vård. Idag finns elva sådana prioriteringsordningar presenterade på landstingets intranät och ytterligare ett tiotal är under bearbetning. Utöver vinsterna med det förbättrade samarbetet mellan länsdelarna har alltså den interna öppenheten i prioriteringarna ökat. Alla anställda kan lätt få fram prioriteringsordningarna via basenheternas hemsidor när man behöver det. Andra vinster av prioriteringsarbetet är att kännedomen och kunskapen om riksdagens riktlinjer för prioriteringar har ökat, att en större del av basenheternas verksamhet idag är faktabaserad än innan prioriteringsarbetet startade samt att den kliniska erfarenheten har tillvaratagits och dokumenterats på ett mer systematiskt sätt än tidigare. Det har dessutom skett en utveckling av den nationella modellen som har blivit mer konkret vad det gäller svårighetsgrad och nytta. En majoritet av deltagarna i utvecklingsgrupperna har haft en positiv inställning till att arbeta med prioriteringar utifrån modellen och upplever också att de erhållit ett språk som gör det möjligt att kommunicera prioriteringar med politiker och landstingsledning.

    I rapporten presenteras också de frågor kring modellens olika steg som dykt upp under arbetets gång. Tre frågor har dominerat; syftet med prioriteringsarbetet, tolkningen av modellen samt dokumentationen av prioriteringsarbetet.

     

    Syftet har inte alltid upplevts som helt klart och sambandet mellan prioriteringsarbetet och annat kvalitetsarbete som t ex framtagande av behandlingsriktlinjer har varit otydligt. När det gäller tolkningen av modellen har t ex graderingen av svårighetsgrad och patientnytta gett upphov till frustration. Också den skriftliga presentationen av prioriteringsordningarna har stundtals upplevts som krånglig och svår att förmedla till övriga medarbetare på ett användbart sätt.

    Alla de åtgärder som projektgruppen vidtagit för att underlätta de svårigheter som dykt upp delar de här med sig av i rapporten. Likaså pekar de ut viktiga förutsättningar för ett prioriteringsarbete (som t ex tid, kompetens, kontinuitet och legitima deltagare). Syftet med att pröva om den nationella modellen för öppna vertikala prioriteringar är användbar i Samrehabs och Rehab Söders prioriteringsarbete är uppnådd och det har inte framkommit något som ger anledning att ifrågasätta modellens grundstruktur. Förslag har dock givits bl a avseende bedömning av svårighetsgrad och patientnytta för att ytterligare underlätta tillämpningen.

    Nu planerar enheterna att gå vidare med sitt prioriteringsarbete, dels genom att fortsätta att ta fram behandlingsriktlinjer som kombineras med prioriteringar men också genom att ytterligare utveckla prioriteringsstödet för de enskilda medarbetarna i deras dagliga patientarbete. Om andra verksamheter i Sverige  följer efter detta exempel från Kalmar län med att öppet redovisa hur de hanterar prioriteringar i sin verksamhet kommer ytterligare nya erfarenheter att hjälpa metodutvecklingen på traven.

  • 1075.
    Ahlström, Per
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Signalprediktering i vitt gaussiskt brus med hjälp av ett adaptivt signalanpassat filter1976Report (Other academic)
    Abstract [sv]

    Ett signalanpassat filter har ett impulssvar som är den exiterandesignalens spegelbild . Ett dylikt filter maximerar vid en viss tidpunkt signalbrusförhållandet på utgången.

    Ett adaptivt transversalfilter styrt av en gradientkännande algoritm, vilken maximerar signalbrusförhållandet på filterutgången, har studerats. Det spegelvända impulssvaret har använts som prediktion av signalen. Denna prediktion har, vid simulering gjord på dator, ej visat sig vara bättre än en klassisk prediktion med en ren summering av brusstörda upplagor av signalen. Inte ens då dylika summerade upplagor av den brusstörda signalenanvänts som insignal till filtret har signalprediktionen via filtrets impulssvar uppvisat ett lägre kvadratiskt medelfel än d en klassiska.

  • 1076.
    Ahlström, Petter
    Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems. Linköping University, The Institute of Technology.
    Affärsstrategier för seniorbostadsmarknaden2005Licentiate thesis, monograph (Other academic)
    Abstract [sv]

    Den demografiska utvecklingen i Sverige går mot en befolkningssammansättning med allt högre medelålder. Enligt svenska befolkningsprognoser kommer nästan var fjärde svensk år 2025 att vara över 65 år. Den äldre andelen av befolkningen utgör en välbeställd grupp med relativt stora realekonomiska tillgångar. Attitydundersökningar på morgondagens pensionärer talar för att denna grupp ställer högre krav på boendeutformning, kringservice, vård och omsorg än tidigare generationer. Flera studier visar på en ökad betalningsvilja och betalningsförmåga för alternativa service- och boendeformer. Samtidigt försöker olika marknadsaktörer att positionera ett produkt- och tjänsteutbud inom en bostadsmarknadens nischer, här definierad som seniorbostadsmarknaden. På seniorbostadsmarknaden har ett särskilt segment identifierats där utöver seniorboende även service-, vård- och omsorgsrelaterade kringtjänster bjuds ut. Mot den bakgrunden har avhandlingens problemställning formulerats enligt följande: vad skapar en stark marknadsposition för en aktör på seniorbostadsmarknaden med integrerad service, vård och omsorg?

    Utgångspunkten har varit ett sannolikt scenario där privata initiativ i allt större utsträckning kommer att bidra till framtida boendelösningar riktade till samhällets seniora och äldrebefolkningsgrupper. Syftet med avhandlingen har varit dels att identifiera de framgångsfaktorer som kan antas ligger till grund för en stark marknadsposition, dels att skapa en typologi över olika affärsstrategier. Genom en branschanalys har det i avhandlingen påvisats att seniorbostadsmarknaden är en nischmarknad med marginell omfattning. Avhandlingens empiriska undersökning har designats som en fältstudie. Fältstudien har i sin tur bl.a. genomförts i form av en förstudie och en intervjustudie. Intervjustudien ägde rum under hösten 2004 med platsbesök och intervjuer av verksamhetsföreträdare för elva utvalda fallstudieorganisationer. Utifrån ett antal i förhand uppställda kriterier har marknadsaktörernas framgångsfaktorer identifierats. Den bearbetnings- och analysmodell som konstruerats för detta syfte och som använts för att analysera fältstudiens empiri är baserad på studier inom strategiområdet. Modellen har bl.a. inspirerats av forskare som Miles & Snow (1978), Porter (1980) och Gupta & Govindarajan (1984). Vidare bygger den på antagandena om resursers och kompetensers betydelse för strategiformuleringen. Service management, och då särskilt tjänsters sammansättning, är ett annat område som beaktas. Analysmodellen har byggts upp kring fem dimensioner: omgivning, strategi, resurser, tjänstekoncept och konkurrens. De identifierade framgångsfaktorerna har baserats på intervjustudiens två mest framgångsrika aktörer. Resultatet har formulerats i ett antal strategiska vägval vilka kan sammanfattas i begreppen: differentiering, fokus, integration, samverkan, kontroll, verksamhetsutveckling, kärnkompetens och resurser. I avhandlingen påvisas att aktörer som bedriver framgångsrik verksamhet på seniorbostadsmarknaden till stora delar följer det Porter (1980) definierat som en differentieringsstrategi med fokus. Avhandlingen har också utmynnat i en affärsstrategisk typologi för seniorbostadsmarknaden. Dessa tentativa slutsatser har formulerats i fyra strategiska idealtyper: förvaltare, konceptbyggare, entreprenörer och idealister.

  • 1077.
    Ahlström, Petter
    Linköping University, Department of Management and Engineering, Economic Information Systems. Linköping University, The Institute of Technology.
    Strategier och styrsystem för seniorboendemarknaden2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The demographic trend in Sweden features a population with a rising average age. According to forecasts, nearly one Swede out of four will be 65 or older by the year 2025. Many individuals in this category of older persons, or seniors, can look forward to an active, healthy and relatively long old age. Studies have shown that tomorrow’s seniors and retirees will be relatively well off as social groups. In addition, attitude and generation surveys have indicated that these groups have high demands and expectations for their old age, future housing and related services. Society will thus face a considerable challenge, which includes maintaining a basic commitment to continue guaranteeing the standard of quality in housing and services for the elderly that is presently taken for granted. Necessary societal priorities, however, may require individuals to take more initiative and assume greater financial responsibility than before in some of these areas. In the 2000’s a new market segment has been established and shown vigorous growth. That segment is the senior housing market, where various housing concepts are offered to the target group, seniors, or persons aged 55+. The number of senior housing units in Sweden has soared in the last few years, from about 10 000 in 2000 to some 28 000 in 2007. In this study, the concept of senior housing, with features of integrated service and care, has been of special interest. What characterizes this housing concept is that housing and related services have been adapted and specially designed for living as an aging individual.

    This dissertation (”the survey”) is reported in the form of a monograph consisting of two separate studies. The research question that has guided the first study is, “What creates a strong market position for a player on the senior-housing market with integrated service, health care and other forms of service and care?” The research question for the second study is, “What production strategies and control systems can be identified for some of the most successful concept-builders?” The two studies are related in that the latter is based on the results of the former. The studies were conducted over a period from 2002 to 2008. The research was done as an exploratory field study. The field-study approach has given priority to breadth and inclusion of many aspects. The instrument of measurement has consisted of set interview questions with open-ended alternative responses. The underlying interviews, together with secondary data, have been presented as a number of case studies. In the survey, a number of successful players have been selected on the basis of the criteria considered typical of successful actors on the senior housing market. Both Swedish and North American organizations have participated in the survey.

    The empirical material of the survey has been analyzed on the basis of the theoretical conceptual frameworks developed for the two respective studies. The first study has been analyzed with a framework based on the concepts of environment, strategy, resources, service and competitiveness. The results have been formulated in a number of strategic choices that are summarized in the concepts of differentiation, focus, integration, collaboration, control, business development, core competence and resources. In this connection, it has been possible to show that actors who operate a successful business follow largely what Porter (1980) has defined as a strategy of differentiation. Moreover, a business-strategy typology of actors on the senior housing market has also been constructed. Also, the tentative conclusions of the first study have been formulated in four strategic ideal types: administrators, concept-builders, entrepreneurs and idealists.

    The point of departure for the second study has been the ideal type referred to as the concept-builder. The conceptual framework has therefore been developed further, based in part on the theoretical framework of Nilsson and Rapp (2005). With certain additions, these foundations have been used to construct a detailed theoretical framework for the study. The conceptual framework has been designed to describe and analyze the causal relationships relating to strategic congruence and integrated control. In this regard, additions and adjustments have been made to include strategies and control systems for the construction of buildings and the production of services. The results of the second study include a case description and an analysis of successful concept-builders. One reason for their success is assumed to be their ability to achieve strategic congruence and integrated control. In light of the findings from the analysis of the data, the conceptual framework has been somewhat modified. This adjustment has consisted in classification along the dimensions of IT, organizational culture and fundamental values. In this connection it has been possible to demonstrate the importance of the physical planning of housing for the production of services. Emphasis has been placed on designing the physical facility and housing right from the beginning so as to facilitate the service-producing operation in a later stage of the life cycle.

    One finding of the survey is that with North American concept-builders there is a high degree of consistency between strategies and control systems. The factors underlying this consistency can be summarized as market knowledge, industry experience, understanding the economies of scale attainable through clustering, organization on a small scale, a clear concept of business, a sense of value creation, a focus on objectives, farreaching delegation of authority and responsibility to the operating level, skilled management, value-oriented operations and a well-developed organizational culture. Through the survey, a number of customer-controlled operations have been illustrated in the case studies. It is apparent that compared to the past, there has been a shift in industry attitude in North America, creating a situation that differs from Swedish conditions in some respects. The North American concept-builders have defined their businesses as hotel operations for seniors. This has automatically shifted the focus toward one where residents have become customers and older people in general are regarded as assets.

  • 1078.
    Ahlström, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Nilsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Affärsstrategier och seniorbostadsmarknaden2005In: Fastighetsnytt, ISSN 1104-8913, Vol. 12 nr 5, p. 36-37Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

      Artikeln beskriver några av resultaten från licentiatavhandlingen "Affärsstrategier för seniorbostadsmarknaden" av Petter Ahlström.      

  • 1079.
    Ahlström, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Nilsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Boende för äldre - utmaningar och möjligheter2007Report (Other academic)
    Abstract [sv]

    Det projekt som här avrapporteras är initierat och finansierat av Sveriges Kommuner och Landstings FoU-fond för fastighetsfrågor. I rapporten diskuteras och analyseras ett antal faktorer som kan antas påverka kommunernas kostnader, i vid bemärkelse, för service, vård och omsorg. Analysen inriktas på hur utformningen av dagens och framtidens boende för äldre kan antas påverka kostnadsläget. Rapporten omfattar 88 sidor.        

  • 1080.
    Ahlström, Petter
    et al.
    Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems. Linköping University, The Institute of Technology.
    Nilsson, Fredrik
    Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems. Linköping University, The Institute of Technology.
    Interaktivt forskningssamarbete med seniorbostadsentreprenörer2003In: The 17th Nordic Conference on Business Studies in Reykjavik, 2003Conference paper (Refereed)
  • 1081.
    Ahlström, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Nilsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Olve, Nils-Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Att mobilisera och vårda samverkan i forskning2007In: Högskolor och samhälle i samverkan 2007 HSS07,2007, 2007Conference paper (Other academic)
    Abstract [en]

    Kunskapsutveckling är en långsiktig process där kontaktskapande och kontaktvård ofta har stor omfattning jämfört med den konkreta forskningsinsatsen. Utmaningen är att mobilisera och vårda en allians där forskare och praktiker samverkar. Ibland kan även finansiärer ha en aktiv roll. Intresse för forskningsinsatsen är en viktig utgångspunkt för samverkan men inte sällan finns det ytterligare orsaker till att ett samarbete kommer till stånd och består. Teoretisk inspiration för att diskutera detta kan hämtas från studier av s.k. imaginära och virtuella organisationer. I uppsatsen diskuteras detta mot bakgrund av erfarenheter från faktiska forskningsprojekt.     

  • 1082.
    Ahlström, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Nilsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Olve, Nils-Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Att mobilisera och vårda samverkan i forskning2008In: Gemensamt kunskapande - den interaktiva forskningens praktik, Växjö: Växjö University Press , 2008, 1, p. 115-132Chapter in book (Other academic)
    Abstract [sv]

    I en tid då universitetens kunskapsmonopol är på väg att brytas får en nära samverkan mellan forskare, finansiär och studieobjekt en allt större betydelse (Nowotny et al., 2002, "Re-thinking Science"). Denna typ av samverkan är en central utgångspunkt i interaktiv forskning där ett vanligt syfte är att bedriva praktiknära studier med stor utomvetenskaplig relevans. I denna uppsats diskuteras hur samverkan mobiliseras och vårdas. Frågor som behandlas är hur forskarnas och praktikernas intressen ska förenas samt vad forskarna kan göra för att skapa rimliga förväntningar hos praktikerna och sprida sina resultat. Diskussionen baseras på egna erfarenheter där ett antal minifall får illustrera vad vi uppfattar vara typiska utmaningar i den här typen av samarbeten.   

  • 1083.
    Ahlström, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Nilsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Olve, Nils-Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Economic Information Systems.
    Mobilising and nurturing collaboration in research - the value of a focused imagination2007In: International Journal of Action Research, ISSN 1861-1303, E-ISSN 1861-9916, Vol. 3, no No 3, p. 297-327Article in journal (Refereed)
    Abstract [en]

       Establishing and nurturing contacts are important and time-consuming elements of interactive research. It is usually the researcher who has to establish and nurture collaboration with practitioners, a task that is not normally part of traditional research. A mutual interest in the subject of the research is a prerequisite for collaboration, but there are quite often other factors that explain why collaboration begins and endures. On the basis of the experience gained in a number of interactive research projects, we address the conditions required for an effective and lasting interplay between collaborating partners. Theoretical inspiration has been provided by studies of so-called imaginary organisations.        

  • 1084.
    Ahlström, Tobias
    et al.
    Linköping University, Department of Electrical Engineering.
    Danev, Danyo
    Linköping University, Department of Electrical Engineering.
    Superimposed Codes for CDMA over Fiber Optic Channels2004In: Ninth International Workshop on Algebraic and Combinatorial Coding Theory,2004, 2004, p. 14-19Conference paper (Refereed)
  • 1085.
    Ahlsén, Carl
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Felczak, Michael
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Hinder & möjligheter med dagvattenhantering: Fallstudier över Linköping och Norrköping kommuns arbete med alternativ dagvattenhantering2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    More frequent and intensified rainfalls are expected to occur due to climate change in the nearfuture. This together with a higher proportion of paved areas increases the pressure on today’sstorm water systems (Risinger, 2014; Boverket, 2013; Stahre, 2006). Traditional storm watersystems (i.e. underground pipe systems) have during last decades started to be questioned(Olshammar & Baresel, 2012). The precipitation over Sweden is expected to increase 10-20% over the next century (SMHI, 2009). Increased precipitation may cause temporary capacityloss in pipe-based storm water system with flooding in sensitive areas as a result (Östlund &Lagerblad, 2011). To decrease the potential stress on traditional storm water systems,sustainable urban drainage systems have started to be developed (Viklander & Bäckström,2008). The era of traditional storm water systems has reached a breaking point and moresustainable storm water systems has become more desired as a complement to today’ssystems (Cettner et al, 2014; Semadeni-Davies et al., 2007). In order to build an increaseunderstanding sustainable storm water management it is decisive to investigate what obstaclesthat municipalities has to tackle, regarding storm water management. This study aims toanalyze problems that may occur concerning storm water management including whatchallenges and possibilities that municipalities have to face. The study is based on qualitativeinterviews with informants in the municipalities of Linköping and Norrköping to see how theyare working with storm water and sustainable storm water management. The conclusions ofthe study is mainly, the need for a more pronounced governance, a more explicit demandconcerning laws and regulations, in particular the Swedish planning and building act, acommon vision about how storm water management practices should be handled and finallyquestions concerning how storm water should be handled in an early stage in the planningprocess. This is the main factors to facilitate the work with sustainable urban drainage system.

  • 1086.
    Ahlsén, Elisabeth
    et al.
    Göteborgs Universitet.
    Eklund, Robert
    Linköping University, Department of Culture and Communication, Language and Culture. Linköping University, Faculty of Arts and Sciences.
    Språk, hjärnan och kognition2012In: Kognitionsvetenskap / [ed] Jens Allwood & Mikael Jensen, Lund: Studentlitteratur, 2012, 1, p. 437-552Chapter in book (Other academic)
    Abstract [sv]

    Kognitionsvetenskap är den första boken på svenska som beskriver kärnan i kognitionsvetenskap - att förstå hur människor tänker. Den spänner därmed över ett brett tvärvetenskapligt fält som inrymmer filosofi, lingvistik, psykologi, antropologi, datavetenskap och neuro­vetenskap. Författarna beskriver hur ämnet har vuxit fram och hur man kan studera kognition utifrån filosofiska, psykologiska och neurovetenskapliga aspekter. Även språkvetenskapliga och sociala aspekter på tänkande presenteras. Författarna tar dessutom upp relationen mellan mänskligt tänkande och djurs tänkande, samt utvecklingen av kognition från barndom till vuxen ålder. Avslutningsvis berörs flera aspekter av tänkande i förhållande till teknologi, både som stöd för tänkande och som simulering av tänkande.

    Boken vänder sig till studenter som läser introduktionskurs eller grundkurs i kognitionsvetenskap, men är även lämplig för beteendevetenskapliga eller språkinriktade utbildningar. Den kan även vara av intresse för alla som vill förstå mer om mänskligt tänkande.

  • 1087.
    Ahlsén, Hanna
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    The Effects of Abiotic Stress on Alternative Splicing in Non-specific Lipid Transfer Proteins in Marchantia polymorpha2018Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Due to global warming, our planet will experience more extreme weather conditions. Plants can protect themselves against these abiotic stress conditions with their stress response, which includes alternative splicing of certain genes. Alternative splicing is a post-transcriptional process where a single gene gives rise to different mRNAs, which in turn produces different proteins. In plants, this is usually done by intron retention. One type of protein that may be involved in this stress response are the non-specific lipid transfer proteins (LTPs). Indeed, evidence of intron retention has been found in the LTP genes in the liverwort Marchantia polymorpha, called MpLTPd. To investigate whether this alternative splicing is caused by abiotic stress or not, I subjected the moss to two different types of stress trials, drought and cold, and compared the general expression of the intron in MpLTPd2 and MpLTPd3 from the stressed samples to samples from a moss grown under normal conditions. I found that the expression of the intron did change in the stressed moss, but none of the differences were significant. This suggests that alterative splicing in MpLTPd2 and MpLTPd3 is not caused by cold and drought and that the intron-containing protein plays no role in the protection of M. polymorpha against abiotic stress.

  • 1088.
    Ahlsén, Olle
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies.
    Att löta en ring, eller ser jag mönster i cirklar?: En undersökning av en underutnyttjad snickeriteknik2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Var, när, hur och vad jag kom fram till.

    Utifrån egna erfarenheter från olika uppgifter under min treåriga utbildning och utifrån de ytterligare trevare jag gjort inom ramen för mitt examensarbete, så har jag undersökt lötade ringars tekniska, estetiska och berättande möjligheter.

    Med olika hållbarhetstester är styrkan prövad och med ett antal varierade dekorativa bearbetningar inom lötningstekniken är de estetiska möjligheterna synliggjord.

  • 1089.
    Ahlvin, Anna
    et al.
    Linköping University. Region Östergötland, Public Dental Health Care.
    Warnberg Gerdin, Elisabeth
    Regional Örebro County, Sweden.
    Bågesund, Mats
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Public Dental Health Care.
    Ordell, Sven
    Region Östergötland, Public Dental Health Care.
    Self-perceived oral health among 19-year-olds in a Swedish County - A comparative study between 2004 and 20112016In: Swedish Dental Journal, ISSN 0347-9994, Vol. 40, no 1, p. 53-65Article in journal (Refereed)
    Abstract [en]

    For decades, Swedish dental professionals have collected clinical epidemiological data from the dental records. To supplement the epidemiology, Ostergotland County Council decided to examine patient perceptions of oral health: self-rated knowledge, self-perceived oral health, and opinions about oral health. The aim was to compare self-perceived oral health among 19-year-olds to determine differences between genders, various municipalities and between 2004 and 2011. This study analysed the responses from two cross-sectional surveys of the entire population of 19-year-olds in Ostergotland County, Sweden, performed in 2004 and 2011. Of the 2,413 (53 %) (50 % men, 50 % women) 19-year-olds who responded to the questionnaire in 2004 and the 3,803 (67 %) (50 % men, 50 % women) in 2011, most 19-year-olds (88.1 % [2004] and 87.5 % [am]) reported satisfaction with their oral health. Around half of the respondents rated their knowledge on periodontitis as low. Boys rated their knowledge about avoiding periodontitis higher than girls (p<0.05 in 2004 and p<0.001 in 2011). In 2004, 84.7 % reported shooting pain. In 2011 that figure was 83.7 %. The respondents expressed some uncertainty about the benefits of fluoride toothpaste (7.5 % in 2004 and 9.3 % in 2011), especially the boys (10.3 % in 2004 and 10.5 % in 2011). Girls reported both a higher social impact and greater concern about aesthetics related to their oral health. They also reported headache (27.5 %) nearly twice as often as boys (14.2 %) (p>0.001). Responses between the municipalities did not differ, with the exception of items regarding periodontitis. Thus, this study found indications that perceptions of oral health and knowledge in Ostergotland County complied with Swedish Dental Act. The study also found patient perceptions of oral health among 19-year-olds to be good.

  • 1090.
    Ahlén, Mattias
    et al.
    Linköping University, Department of Thematic Studies.
    Ericsson, Per
    Linköping University, Department of Thematic Studies.
    Lester Bangs har aldrig varit i Tranås: Den kulturella navigationen hos rockkritiker i svensk dagspress2002Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [sv]

    "Lester Bangs har aldrig varit i Tranås" är en kultursociologisk studie i syfte att testa hållbarheten i begreppet"kulturell navigation", samt att genom kvalitativ metod visa på skillnader och likheter i Svenska musikkritikers kulturella navigationsvägar. Genom intervjuer med sju musikkritiker, alla från svensk dagspress, strävar uppsatsen efter att visa på varje individs specifika kulturella navigation för att nå en offentlig tyckarposition. Ledordet för intervjuer och för arbetet i stort har varit "Hur?". Hur navigerar en individ genom kulturen för att skaffa sig det kapital som är gångbart på ett specifikt fält?

    Begreppen kapital och fält är hämtade ur Pierre Bourdieus sociologiska teori och med analysstöd av dessa begrepp ger uppsatsen dessutom några ledtrådar till "Varför" musikkritikerna navigerat som de gjort. Här finns exempelvis intressanta skillnader mellan storstadstidningens skribenter och landsbygdstidningens skribenter. Det kulturella navigationsbegreppet diskuteras och etableras i uppsatsen till förmån för frågan "hur?". Uppsatsen lämnar därmed arbetet med att förfina och underbygga begreppet, så att det också kan börja förklara "varför", till eventuella fortsättningsarbeten.

  • 1091.
    Ahmad, Ban
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Vieglins, Gustav
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A energy and cost comparison between a BBR and a passive apartment building2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Idag ställer samhället och konsumenterna allt större krav på klimatsmarta boenden för att minska energianvändningen. Trots det byggs fortfarande till stor del traditionella hus efter Boverkets byggregler. På uppdrag av WSP studerar denna rapport hur energiåtgången hos ett befintligt flerbostadshus i Stockholm, byggt efter BBR, hade sett ut om det uppförts för att fylla kravspecifikationen för passivhus enligt FEBY12. Samt hur livscykelkostnaderna hade skiljt sig för de två husen.

    Studien inleddes med en datainsamling av för det befintliga flerbostadshusets areor samt Uvärdena och följs upp med simuleringar av flerbostadshuset i beräkningsprogrammet Energihuskalkyl. Datorberäkningarna jämfördes med manuella beräkningar för att säkerställa värmeförlusttalet samt andelen köpt energi. Varefter flerbostadshuset anpassades med Kingspans detaljbibliotek för att uppfylla FEBY12s passivhuskrav och följdes upp med samma dator- och manuella beräkningar. Där de båda resultaten presenteras och jämförs.

    I rapportens andra del undersöks och jämförs de två flerbostadshusens livscykelkostnader, sett till investerings-, drifts- och underhållskostnader. Då beställaren sekretessbelagt de verkliga kostnaderna antogs de verkliga kostnaderna för det befintliga huset från Statistiska Centralbyrån. För att beräkna det teoretiska passivhusets investeringskostnader beräknades materialkostnaderna för de båda husen efter de givna ritningarna. Där skillnaden i materialkostnaderna adderades till investeringskostnaden för det passiva flerbostadshuset.

    Underhållskostnaderna antogs till detsamma för det passiva flerbostadshuset samtidigt som att driftskostnaderna sänktes procentuellt med den minskade mängden köpt energi från energiberäkningarna.

  • 1092.
    Ahmad, Faiyaz
    et al.
    NHLBI, Translat Med Branch, NIH, Bethesda, MD 20892 USA .
    Lindh, Rebecka
    Lund University, Department Expt Med Science, S-22184 Lund, Sweden .
    Tang, Yan
    NHLBI, Translat Med Branch, NIH, Bethesda, MD 20892 USA .
    Ruishalme, Iida
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Öst, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Sahachartsiri, Bobby
    NHLBI, Translat Med Branch, NIH, Bethesda, MD 20892 USA .
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Degerman, Eva
    Lund University, Department Expt Med Science, S-22184 Lund, Sweden .
    C Manganiello, Vincent
    NHLBI, Translat Med Branch, NIH, Bethesda, MD 20892 USA .
    Differential regulation of adipocyte PDE3B in distinct membrane compartments by insulin and the beta(3)-adrenergic receptor agonist CL316243: effects of caveolin-1 knockdown on formation/maintenance of macromolecular signalling complexes2009In: BIOCHEMICAL JOURNAL, ISSN 0264-6021, Vol. 424, no 3, p. 399-410Article in journal (Refereed)
    Abstract [en]

    In adipocytes, PDE3B (phosphodiesterase 3B) is an important regulatory effector in signalling pathways controlled by insulin and cAMP-increasing hormones. Stimulation of 3T3-L1 adipocytes with insulin or the beta(3)-adrenergic receptor agonist CL316243 (termed CL) indicated that insulin preferentially phosphorylated/activated PDE3B associated with internal membranes (endoplasmic reticulum/Golgi), whereas CL preferentially phosphorylated/activated PDE3B associated with caveolae. siRNA (small interfering RNA)-mediated KD (knockdown) of CAV-1 (caveolin-1) in 3T3-L1 adipocytes resulted in down-regulation of expression of membrane-associated PDE3B. Insulin-induced activation of PDE3B was reduced, whereas CL-mediated activation was almost totally abolished. Similar results were obtained in adipocytes from Cav-1-deficient mice. siRNA-mediated KID of CAV-1 in 3T3-L1 adipocytes also resulted in inhibition of CL-stimulated phosphorylation of HSL (hormone-sensitive lipase) and perilipin A, and of lipolysis. Superose 6 gel-filtration chromatography of solubilized membrane proteins from adipocytes stimulated with insulin or CL demonstrated the reversible assembly of distinct macromolecular complexes that contained P-32-phosphorylated PDE3B and signalling molecules thought to be involved in its activation. Insulin- and CL-induced macromolecular complexes were enriched in cholesterol, and contained certain common signalling proteins [14-3-3, PP2A (protein phosphatase 2A) and cav-1]. The complexes present in insulin-stimulated cells contained tyrosine-phosphorylated IRS-1 (insulin receptor substrate 1) and its downstream signalling proteins, whereas CL-activated complexes contained beta(3)-adrenergic receptor, PKA-RII [PKA (cAMP-dependent protein kinase)-regulatory subunit] and HSL. Insulin- and CL-mediated macromolecular complex formation was significantly inhibited by CAV-1 KID. These results suggest that cav-1 acts as a molecular chaperone or scaffolding molecule in cholesterol-rich lipid rafts that may be necessary for the proper stabilization and activation of PDE3B in response to CL and insulin.

  • 1093.
    Ahmad, Fareed
    et al.
    Hannover Medical Sch, Germany.
    Shankar, Esaki M.
    University of Malaya, Malaysia; University of Malaya, Malaysia; School Basic Appl Science, India.
    Yong, Yean K.
    University of Malaya, Malaysia.
    Tan, Hong Y.
    University of Malaya, Malaysia.
    Ahrenstorf, Gerrit
    Hannover Medical Sch, Germany.
    Jacobs, Roland
    Hannover Medical Sch, Germany.
    Larsson, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Schmidt, Reinhold E.
    Hannover Medical Sch, Germany.
    Kamarulzaman, Adeeba
    University of Malaya, Malaysia; University of Malaya, Malaysia.
    Ansari, Abdul W.
    University of Malaya, Malaysia; University of Malaya, Malaysia.
    Negative Checkpoint Regulatory Molecule 2B4 (CD244) Upregulation Is Associated with Invariant Natural Killer T Cell Alterations and Human Immunodeficiency Virus Disease Progression2017In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 8, article id 338Article in journal (Refereed)
    Abstract [en]

    The CD1d-restricted invariant natural killer T (iNKT) cells are implicated in innate immune responses against human immunodeficiency virus (HIV). However, the determinants of cellular dysfunction across the iNKT cells subsets are seldom defined in HIV disease. Herein, we provide evidence for the involvement of the negative checkpoint regulator (NCR) 2B4 in iNKT cell alteration in a well-defined cohort of HIV-seropositive anti-retroviral therapy (ART) naive, ART-treated, and elite controllers (ECs). We report on exaggerated 2B4 expression on iNKT cells of HIV-infected treatment-naive individuals. In sharp contrast to CD4-iNKT cells, 2B4 expression was significantly higher on CD4+ iNKT cell subset. Notably, an increased level of 2B4 on iNKT cells was strongly correlated with parameters associated with HIV disease progression. Further, iNKT cells from ARTnaive individuals were defective in their ability to produce intracellular IFN-gamma Together, our results suggest that the levels of 2B4 expression and the downstream co-inhibitory signaling events may contribute to impaired iNKT cell responses.

  • 1094.
    Ahmad, Ijaz
    et al.
    University of Oulu, Finland.
    Kumar, Tanesh
    University of Oulu, Finland.
    Liyanage, Madhusanka
    University of Oulu, Finland.
    Okwuibe, Jude
    University of Oulu, Finland.
    Ylianttila, Mika
    University of Oulu, Finland.
    Gurtov, Andrei
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Faculty of Science & Engineering.
    5G Security: Analysis of Threats and Solutions2017In: 2017 IEEE CONFERENCE ON STANDARDS FOR COMMUNICATIONS AND NETWORKING (CSCN), IEEE , 2017, p. 193-199Conference paper (Refereed)
    Abstract [en]

    5G will provide broadband access everywhere, entertain higher user mobility, and enable connectivity of massive number of devices (e.g. Internet of Things (IoT)) in an ultrareliable and affordable way. The main technological enablers such as cloud computing, Software Defined Networking (SDN) and Network Function Virtualization (NFV) are maturing towards their use in 5G. However, there are pressing security challenges in these technologies besides the growing concerns for user privacy. In this paper, we provide an overview of the security challenges in these technologies and the issues of privacy in 5G. Furthermore, we present security solutions to these challenges and future directions for secure 5G systems.

  • 1095.
    Ahmad, Ijaz
    et al.
    Univ Oulu, Finland.
    Liyanage, Madhusanka
    Univ Oulu, Finland.
    Ylianttila, Mika
    Univ Oulu, Finland.
    Gurtov, Andrei
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Faculty of Science & Engineering.
    Analysis of Deployment Challenges of Host Identity Protocol2017In: 2017 EUROPEAN CONFERENCE ON NETWORKS AND COMMUNICATIONS (EUCNC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    Host Identity Protocol (HIP), a novel internetworking technology proposes separation of the identity-location roles of the Internet Protocol (IP). HIP has been successful from the technological perspectives for network security and mobility, however, it has very limited deployment. In this paper we assess HIP to find the reasons behind its limited deployment and highlight the challenges faced by HIP for its commercial use. We propose technological development and outline deployment strategies for the wide use of HIP. Furthermore, this paper investigates the use of HIP in Software Defined Networks (SDN) to evaluate its performance in new disruptive networking technologies. In a nutshell, this paper presents revealing challenges for the deployment of innovative networking protocols and a way ahead for successful and large scale deployment.

  • 1096.
    Ahmad, M. Rauf
    Linköping University, Department of Mathematics.
    A note on the (n, p)-asymptotics of ATS for high dimensional multivariate data2010Report (Other academic)
  • 1097.
    Ahmad, M. Rauf
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    A two-sample test statistic for high-dimensional multivariate data under non-normality2011Report (Other academic)
    Abstract [en]

    Ahmad, Ohlson, and von Rosen (2011a) present asymptotic distribution of a one-sample test statistic under non-normality, when the data are high dimensional, i.e., when the dimension of the vector, p, may exceed the sample size, n. This paper extends the case to a two-sample statistic to test the difference of mean vectors of two independent multivariate distributions, again under high-dimensional set up. Using the asymptotic theory of U-statistics, and under mild assumptions on the traces of the unknown covariance matrices, the statistic is shown to follow an approximate normal distribution when n and p are large. However, no relationship between n and p is assumed. An extension to the paired case is given, which, being essentially a one-sample statistic, supplements the asymptotic results obtained in Ahmad, Ohlson, and von Rosen (2011a).

  • 1098.
    Ahmad, M. Rauf
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Robustness of a one-sample statistic for mean testing of high dimensional longitudinal data2010Report (Other academic)
  • 1099.
    Ahmad, M. Rauf
    et al.
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    Ohlson, Martin
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    von Rosen, Dietrich
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    A U-statistics Based Approach to Mean Testing for High Dimensional Multivariate Data Under Non-normality2011Report (Other academic)
    Abstract [en]

    A test statistic is considered for testing a hypothesis for the mean vector for multivariate data, when the dimension of the vector, p, may exceed the number of vectors, n, and the underlying distribution need not necessarily be normal. With n, p large, and under mild assumptions, the statistic is shown to asymptotically follow a normal distribution. A by product of the paper is the approximate distribution of a quadratic form, based on the reformulation of well-known Box's approximation, under high-dimensional set up.

  • 1100.
    Ahmad, M. Rauf
    et al.
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    Ohlson, Martin
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    von Rosen, Dietrich
    Department of Energy and Technology, Swedish Univerity of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
    Some Tests of Covariance Matrices for High Dimensional Multivariate Data2011Report (Other academic)
    Abstract [en]

    Test statistics for sphericity and identity of the covariance matrix are presented, when the data are multivariate normal and the dimension, p, can exceed the sample size, n. Using the asymptotic theory of U-statistics, the test statistics are shown to follow an approximate normal distribution for large p, also when p >> n. The statistics are derived under very general conditions, particularly avoiding any strict assumptions on the traces of the unknown covariance matrix. Neither any relationship between n and p is assumed. The accuracy of the statistics is shown through simulation results, particularly emphasizing the case when p can be much larger than n. The validity of the commonly used assumptions for high-dimensional set up is also briefly discussed.

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