| 1. |
- Byttner, Stefan
(författare)
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Real-time control of an SI engine using ion current based algorithms
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Reducing emissions and improving fuel efficiency in automobiles are today important issues. New sensor techniques are developed to extract detailed combustion information to enable closed loop engine control. This thesis is about a virtual sensor; measuring an ion current inside the cylinder by using the already existing spark plug, followed by signal processing for estimation of combustion parameters. First, the thesis aims to show that the ion current signal can be used for closed loop control of Exhaust Gas Recirculation (EGR). Use of EGR is very common in modern automobiles because of the potential reduction of NOx emissions and fuel consumption, but using too much EGR can have the reverse effect (e.g. increased fuel consumption and driveability problems). Algorithms for estimating combustion variability are proposed and a closed loop scheme for controlling an EGR valve is demonstrated for driving on the highway in a SAAB 9000. Estimation of the pressure peak position is treated for closed loop control of ignition timing. Such estimation can be performed with the ion current but may not work if a fuel additive is used. Different methods are compared and it is shown that using a fuel additive may even improve the estimation accuracy of the pressure peak position with about 25%. An algorithm is also proposed to estimate the pressure peak position even in presence of EGR. Strategies for transient control of the air-fuel ratio are also compared. Air-fuel ratio control is important because even small deviations from the stoichiometric value can result in significantly increased emissions. It is found that a neural network based controller had the best performance with approximately 23% lower RMS error than the adapted standard control module.
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| 2. |
- Florén, Henrik, 1972-
(författare)
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Managerial work and learning in small firms
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with how managerial work sets the agenda for managerial learning in small firms. Although studies of learning in organizations are numerous, research on managerial learning in the small-firm context is limited. In particular, our knowledge of managerial learning suffers from an insufficient understanding of what top managers in small firms do. The primary purpose of this thesis is to describe how the work of small-firm managers sets the agenda for managerial learning, and how their learning can be supported. Additionally, the thesis explores the use of so-called “Action Technologies” in supporting managerial learning in small firms.Drawing on an observational study of six owner-managers in small (17-43 employees) manufacturing firms, and a synthesis of earlier studies, this thesis shows that three features of managerial work shape managerial learning in small firms: The small firm’s top manager (i) operates in context with specific structural conditions that affect his/her behavior, (ii) have certain cognitive predispositions guiding his/her behavior, and (iii) have certain behavioral preferences directing his/her behavior.The main argument in this thesis is that managerial learning in small firms is made difficult due to features that make it hard to come to a point where learning (in terms of reflection and conceptualization) is given time and resources, as the manager has trouble in finding time for learning, and as learning risks to become low-priority. Learning is also difficult due to barriers related to the learning process: the work of the manager fosters a superficial learning orientation, makes it difficult to probe deeply into and to develop complicated understandings of issues at hand, and makes peer-learning rarely possible.Drawing on an action research project of managerial learning in four networks of small-firm owner-managers, the thesis also explores, in a concrete manner, how managerial learning might be supported in a way that circumvents the deficient situation for managerial learning in this kind of firm. More specifically, it seems that Action Technologies by their design constitute a learning context that supports the learning of the small-firm top manager by dissolving the barriers to learning identified above.
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| 3. |
- Frishammar, Johan
(författare)
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Towards a theory of managing information in new product development
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with various information aspects of new product development (NPD). In total, the thesis consists of 6 research articles appended in full, and an introductory text that integrates and theorizes with and from these papers.The first paper is a review article examining the literature on and role of information in NPD. The main argument put forward here is that information processing can be understood in terms of three steps: acquiring, sharing, and using information. The second paper is a largescale survey that examines the relationship between market and entrepreneurial orien-tation and performance in NPD. A market orientation is to a large extent about acquiring, disseminating and using market information, while an entrepreneurial orientation partly is about ignoring such information, and instead trying to be innovative, proactive, and take risks. The results show that a market orientation and innovativeness are positively related to NPD performance, and that neither product nor environmental characteristics moderate these relationships. The third paper is also a survey, and investigates the extent to which management of external information is associated with innovation performance. The main findings are that scanning the technological sector of the environment was positively associated with innovation performance, while scanning customers, suppliers, and competitors proved to be negatively correlated with innovation performance. Crossfunctional integration in the form of collaboration as well as using information from the industry environment also proved to be positively related to innovation performance.The last three papers have a centre of gravity in “management of information & environ-ment”, and not so much in new product development per se. Paper four describes and com-pares different information processing approaches (e.g. environmental scanning, marketing research) in order to identify their similarities and differences, but also their underlying con-cepts and the course of events they represent. The main conclusion is that differences exist primarily in terms of focus and scope. Paper five is a review and tentative integration of different perspectives in organization – environment research: the adaptive, the resource-dependence, the cognitive and the population-ecology perspective. The review identifies differences and similarities among these perspectives, suggests tentative conclusions on why the adaptive perspective is so frequently utilized at the expense of the other three, and suggests constructivism as a feasible avenue for combining and integrating these perspectives. Finally, the sixth and final paper deals with information use in the context of strategic decisionmaking. With a case study approach, the questions of why information is used, what kind of information is used, where it is obtained, and how it is obtained were addressed, and the results from this paper are mainly descriptive.The purpose of the introductory text is two-fold. In addition to providing integration of the appended papers, the main purpose is theory construction (i.e. elicitation of constructs and propositions). In the introduction, all six appended papers together with a new literature search and a new pilot case study are used to generate propositions about management of information, information sources, and the need for cross-functional integration in three different phases of the NPD process. In addition, suggestions regarding theoretical connections are made. The introduction text concludes with reflections, managerial implications, limitations, and future research.
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| 4. |
- Nilsson, Kenneth
(författare)
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Symmetry Filters Applied to Fingerprints : Representation, Feature extraction and Registration
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A common framework for feature extraction in fingerprints is proposed by use of certain symmetries. The proposal includes representation, filters, and filtering techniques for common features including minutiae points, singular points and the ridge and valley patterns.The filters are complex and are designed to identify certain symmetries called rotational symmetries and they are applied to the squared complex gradient field of an image. The filters are used as extractors for known fingerprint features. The filter response magnitude is a certainty measure for existence of a symmetry and its argument is the spatial orientation of that symmetry. This means that the position and the spatial orientation of the fingerprint feature are estimated in a single filtering step jointly. In the proposed framework the position and orientation of singular points are extracted using a multi-scale filtering technique. This strategy is taken to increase the signal-to-noise ratio in the extraction and can be done because singular points have a large spatial support from the orientation field. Experiments show that position is extracted by a precision of 5 ± 3 pixels1 and the orientation by a precision of 0 ± 4° with an EER of approximately 4%. The estimated position and orientation of singular points are used in an alignment experiment which yielded an unbiased alignment error with a standard deviation of 13 pixels 1.A one modality multi-expert registration experiment is presented using singular points and orientation images to estimate the registration parameters.1A fingerprint wavelength is in average 10 pixels.
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| 5. |
- Politis, Diamanto
(författare)
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Entrepreneurship, Career Experience and Learning - Developing Our Understanding of Entrepreneurship as an Experiential Learning Process
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Why are some individuals more successful in recognizing and exploiting new venture opportunities than others? The common view is that successful entrepreneurs have acquired and developed specific types of knowledge through their previous career experiences, which in turn facilitate their involvement in the entrepreneurial process from opportunity recognition to opportunity exploitation. If this is true, how can we understand the learning mechanisms that underlie this experiential learning process? The overall purpose of this dissertation is to develop concepts that enhances our understanding of entrepreneurship as an experiential learning process, and based on this development to empirically test a conceptual framework that explains how individuals develop entrepreneurial knowledge through experiences acquired in their careers. To meet the overall purpose five individual studies have been conducted. The empirical data consists of both personal interviews as well as a large-scale mail questionnaire on Swedish entrepreneurs. The overall findings imply that entrepreneurship should be conceived as a lifelong learning process that proceeds both before and after the initial start-up of a new venture. This means that the sequences of events whereby individuals enter an entrepreneurial career and learn how to recognize and exploit new ventures opportunities needs to be understood in the light of individuals? career experiences as a whole. Entrepreneurial learning is consequently not something that only occurs in typical entrepreneurial settings but also in the everyday working life of individuals well before they even think of being involved in new venture creation. Moreover, the overall findings suggest the need to reconsider the predominant view on entrepreneurial learning which presumes a direct link between a particular experience and the knowledge gained from this experience. The empirical results show that different types of career experiences lead to different types of entrepreneurial knowledge, and that the knowledge developed also depends on the entrepreneurs? preferred mode of transforming experience to knowledge, i.e. whether they prefer putting their emphasis on exploring new possibilities or exploiting their pre-existent knowledge. Consequently, there is a need to distinguish between the two concepts "experience" and "knowledge" if we are to understand entrepreneurship as an experiential learning process.
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| 6. |
- Premaratne, Hemakumar Lalith
(författare)
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Recognition of printed Sinhala characters by direction fields
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although substantial research has been carried out on Optical Character Recognition (OCR) where a printed or a handwritten document of script is read as an image and converted to the editable text format, for various languages during the last 30 years, majority of Brahmi descended south Asian scripts are yet to achieve a commercial OCR system.
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| 7. |
- Roxberg, Åsa
(författare)
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Vårdande och icke-vårdande tröst
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med avhandlingen är att, ur ett vårdvetenskapligt, och ett i detta inkluderat vårdteologiskt per- spektiv, belysa innebörden av fenomenet tröst och hur tröst förhåller sig till lidande och vård. Det görs i två empiriska intervjustudier med vårdare och äldre vårdtagare samt en tredje delstudie som analyse- rar tröst såsom den framstår i Jobs bok i Gamla testamentet. Dessa delstudier behandlar vårdares upp- levelse av tröst och att trösta, äldre vårdtagares upplevelse av tröst samt Jobs upplevelse av tröst.Metodologiskt har forskningen sin utgångspunkt i fenomenologi och hermeneutik. En fenomenolo- gisk-hermeneutisk metod, inspirerad av Paul Ricoeur, har använts för textanalyserna. I avhandlingen behandlas också det som är signifikant för poetisk och religiös text. De metaforer som förekommer i de empiriska delstudierna med vårdare och äldre analyseras för att ta tillvara det överskott av mening som metaforer, enligt Ricoeur, kan uttrycka.Resultatet visar fem övergripande innebörder: Den motsägelsefulla trösten, Den sammanbindande trösten, Den stumma trösten, Den okontrollerade trösten och Den vilsamma trösten. En vårdande tröst är motsägelsefull såtillvida att den innebär dels att den lidande överlämnar sitt lidande till någon an- nan, dels att lidandet kan ges tillbaka för att lidas. Tröst kan således vara att lida. En sammanbindande tröst är närvarande, d.v.s. är hos den lidande och utgår från dennes lidande. Denna tröst kännetecknas av djup gemenskap, en upplevelse av att vara förstådd på ett djupare sätt. Resultatet visar också en tröst som är stum. Denna tröst svarar inte an på den lidandes upplevelse av sitt lidande, är oformlig och saknar följsamhet för lidandet. Ett exempel på en stum och icke-vårdande tröst är vännernas tröst i Jobs bok. Denna tröst förmår inte trösta därför att den inte är där Job är, d.v.s. i hans upplevelse av sitt lidande. Vidare framstår en vårdande tröst som okontrollerad därför att den dels är spontan, dels bistår den lidande att släppa kontrollen över lidandet. Att släppa kontrollen innebär bl.a. att den lidande ger upp försöken att förstå lidandet för att istället låta det oförståeliga vara oförståeligt. Genom att ge upp det som på olika sätt binder lidandet infinner sig en tröstande och hälsobringande vila i eller från li- dandekampen.Resultatet som helhet tolkas ur ett vårdvetenskapligt perspektiv som vårdgemenskap, tro, hälsa och offer. Tröst som hälsa förstås utifrån en teoretisk modell, inspirerad av Katie Erikssons ontologiska hälsomodell. Filosofiskt-etiskt belyses forskningen utifrån företrädesvis Emmanuel Levinas. Resultatet diskuteras i förhållande till tidigare forskning och i förhållande till vårdvetenskap, samhälle och vård.
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| 8. |
- Soleimani Mohseni, Mohsen
(författare)
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Modelling and Intelligent Climate Control of Buildings
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of the work presented in this thesis is to examine the possibilities of different control techniques together with intelligent building technology to improve the indoor climate and/or the energy efficiency of buildings. In particular, the possibilities of measuring more variables and using them as input to the controllers are examined. The first part of the thesis deals with different ways to obtain dynamic models for climate systems in buildings. A large part of the thesis then deals with the feed-forward control strategy and how it affects the indoor climate and the energy use. The main conclusion, drawn from the simulations in this part is that a more extensive use of feed-forward from internal disturbances could be very advantageous in many temperature-control applications. It gives better controller performance, and, at the same time, it will often reduce the energy use. Different controllers (P, PI, PID and ON/OFF with and without dead-band) used for indoor climate control are also investigated in this thesis. The results show that simple controllers like an ON/OFF controller with dead-band or a P-controller often performs better than more advanced controllers in many temperature-control applications. Similar types of controllers have also been investigated when they are used in a demand-control ventilation (DCV) system. The results show that there is a large potential of reducing the outdoor air flow rate by using a DCV-system instead of a base/forced ventilation system. However, the differences between different controllers in a DCV-system are of less importance in these systems. A large part of this thesis is about the problem how to develop mathematical models for prediction of the indoor temperature using linear models as well as non-linear artificial neural network (ANN) models. The results show that neural network models give more accurate predictions of indoor temperature than linear models. ANN-models have also been used for estimation of the operative temperature in buildings. It is shown that the operative temperature can be estimated fairly well by using variables which are more easily measured and that ANN-models give better estimations than linear models. Finally, neural networks have also been used in a new method for (self) tuning of PI and PID controllers. By measuring a number of points at the step-response of a process and using them as input to a successfully trained neural network, the network can estimate the PI and PID parameters with good accuracy for the same process according to well-known tuning rules for PI and PID controllers.
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| 9. |
- Svensson, Ove, 1945-
(författare)
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Ungdomars spel om pengar : spelmarknaden, situationen och karriären
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Spel om pengar har blivit ett utbrett fenomen i Sverige under 1990-talet, med spelbutiker, spelhörnor i varuhusen, spelmaskiner och spel med kort och på roulette på pubar, pizzerior och restauranger, samt spel på Bingo-Lotto hemma i vardagsrummet. Förutom den ökade tillgången till legala spelformer blir det allt vanligare med spel i miljöer och sammanhang där det inte förekom spel tidigare. Konsekvenserna av detta har ännu inte blivit beskrivna och analyserade av spelforskningen. Det är emellertid sannolikt att ungdomar i ökad omfattning involveras i spel redan under de tidiga tonåren. Det huvudsakliga syftet med denna avhandling är att uppmärksamma och diskutera de sociala konsekvenserna av ungdomars ökade tillgång till spel i samhället, och bidra till en ökad förståelse av spelandet bland ungdomar.En kritisk genomgång av forskningslitteraturen kring spel är en viktig del av avhandlingen. Den försöker att organisera begrepp, teorier och forskningsresultat utifrån olika perspektiv och konstruera en handlingsteoretisk tankeram för att förstå ungdomars spelande.Avhandlingen baseras även på empiriska data som samlades in genom nationell undersökning av svenska folkets spelande. Den första fasen av undersökningen utgjordes av en telefonintervju med slumpmässigt urval av befolkningen i ålder 15 till 74 år. Den andra fasen utgjordes av face-to-face intervjuer med samtliga respondenter som hade spelproblem och en matchad kontrollgrupp, sammanlagt 324 individer varav 96 ungdomar. Spelproblem mättes vid den första fasen av undersökningen och sedan efter två år vid den andra fasen med SOGS-R.Avhandlingen uppmärksammar att spelandet blivit en institutionaliserad del av ekonomin och att många intressenter, inklusive staten, idrottsvärlden och föreningslivet blivit beroende av spelintäkter. Begränsningar och åldersrestriktioner sätter gränser för de ungas spelande, men de förhindrar inte spel, och allmänhetens inställning till spel kan närmast beskrivas som ambivalent eller positiv till spel.Ungdomar verkar se introduktionen i spel som en naturlig del av vuxenblivandet och tillägnelsen av vuxna vanor. De flesta ungdomar spelar oavsett ålder, kön eller socioekonomiska förhållanden för nöjes skull. Men omkring fem till tio procent utvecklar ett mer problematiskt spelande med negativa konsekvenser. En tankeram utvecklas i avhandlingen som relaterar de ungas spelande till, 1) personlig bakgrund och levnadsförhållande, 2) spelsituationen och upplevelsen av rummet, tiden och pengar, 3) konsekvenserna av spelandet i form av upplevelser av flow och begäret att upprepa spelhandlingarna, och 4) intentioner med spelandet.Trots lägre involvering i spel är spelproblem tre gånger så vanliga bland ungdomar i åldern 15 till 17 år än bland övriga deltagare i undersökningen. Det framgår dock av avhandlingen att spelproblemen för de flesta ungdomar är av övergående natur, åtminstone när det gäller mindre omfattande spelproblem.
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| 10. |
- Thorstensson, Carina
(författare)
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Exercise and Functional Performance in Middle-aged Patients with Knee Osteoarthritis
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall purpose of this thesis was to explore the impact of exercise and functional performance on development and treatment of knee osteoarthritis in the middle aged. In this thesis, I have studied a population based cohort of middle-aged subjects (35-54 years, 42 % women) with chronic knee pain at baseline, to evaluate the longitudinal effect of muscle weakness on knee osteoarthritis development, the relationship between muscle function and joint load and the effects of exercise on joint load. I have also studied the effect of exercise on pain and function in another middle-aged cohort (36-65 years, 51 % women) with moderate to severe knee osteoarthritis, and explored their conceptions of exercise as treatment. In the first study, 148 subjects with chronic knee pain underwent radiographic examination and tests of functional performance at baseline. 94 of them had no radiographic signs of knee osteoarthritis. Five years later they had new radiographs taken and 41/94 (44 %) had developed incident knee osteoarthritis. I found that reduced functional performance, assessed by maximum number of one-leg rises from a stool, predicted knee osteoarthritis development. The result was controlled for the previously known risk factors of age, BMI and pain. In the second study, I used 3-dimensional motion analysis to explore the possibility of altering joint load by exercise. The medial compartment joint load (peak adduction moment) during maximum number of one-leg rises was assessed in 13 subjects with early radiographic signs of knee osteoarthritis from the cohort in study one, before and after 8 weeks of exercise. Two subjects were lost to follow up for reasons not related to the knee. The peak adduction moment could be reduced by exercise, and a high maximum number of one-leg rises was associated with lower levels of peak adduction moment. The third study included 61 subjects with moderate to severe radiographic knee osteoarthritis. They were randomized to 6 weeks of intensive exercise or to a control group. The effects of exercise were assessed using questionnaires. No effects were seen on pain or self estimated function, however, the quality of life improved. The individual response to exercise ranged from clinically significant improvement to clinically significant worsening. As an attempt to understand this large inter individual response to exercise, I designed the fourth study, where I interviewed 16 of the 30 patients in the exercise group about their conceptions of exercise as treatment. The interviews were analysed using qualitative methodology, and it was revealed that all patients were aware of the general health benefits of exercise, but had doubts about exercise as treatment of osteoarthritis even if they had perceived pain relief and improvement in physical function from the exercise intervention. The pain experienced during exercise caused the patients to believe that exercise was harmful to their knees, and some of them would prefer not to exercise at all. They thought that exercise should be introduced early during the course of the disease, and all of them expressed the need of continuous encouragement and support to adhere to exercise. From this thesis I conclude that reduced muscle function is a risk factor of knee osteoarthritis development among middle aged subjects with knee pain. Reduced muscle function is associated with increased joint load, which seem to be modifiable by exercise. Initial pain when starting exercise, or occasional pain from exercise, should be treated by combining exercise with pain relief such as analgesics or acupuncture. Pain contributes to the difficulty patients have determining the degree of benefit or damage related to exercise, and thus causes feelings of anxiety and helplessness (paper IV). Pain also seems to interfere with the possibility of achieving increased functional performance (paper II, III, IV).
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