| 1. |
- Christiansson, Marie-Therese, 1966-, et al.
(author)
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Mötet mellan process och komponent : mot ett ramverk för en verksamhetsnära kravspecifikation vid anskaffning av komponentbaserade informationssystem
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Denna avhandling är en kvalitativ studie av hur organisationer kan förenkla och förbättra arbetet med kravspecificering vid anskaffning av komponentbaserade informationssystem. Avhandlingens utgångspunkt är att mer verksamhetsnära och användbara informationssystem kan anskaffas genom att använda en integrerad verksamhetsmodell där verksamhetsanalys och kravspecificering slås samman. Fyra kunskapsområden har studerats och analyserats för att generera ett ramverk som riktar uppmärksamhet mot relevant innehåll och utformning av en integrerad verksamhetsmodell, 1) verksamhetsprocesser 2) verksamhetsmodellering 3) mjukvarukomponenter och 4) specificering. Avhandlingens empiri representeras av en rekonstruktion av den komponent- och processorienterade anskaffning av ett komplett vårdinformationssystem som genomförts i Landstinget i Värmland. Analyser och respektive kunskapsområde har skett utifrån ansatsen Multi-Grounded Theory vilket innebär en reorigenerering utifrån en växelverkan mellan existerande teorier och empirisk grundning. Några exempel på kunskapsbidrag är ett vidareutvecklat processbegrepp samt en ny livscykelmodell för komponentbaserade informationssystem. Utifrån kunskapsbidragen inom respektive kunskapsområde har integrationssynpunkter identifierats som legat till grund för utveckling av ramverket för en verksamhetsnära kravspecifikation. I avhandlingen dras slutsatsen att genom att integrera arbetet med verksamhetsanalys och kravspecificering skapas bättre förutsättningar för att kravspecifikationer speglar de behov systemen är avsedda att uppfylla och att gapet mellan krav och lösning minskar genom ett bättre underlag för kommunikation mellan kund och systemleverantör. Ramverket pekar på att en verksamhetsnära kravspecifikation utformas i en integrerad processmodell som beskriver verksamhetsprocesser utifrån identifierade generiska processbegrepp samt ett scenario för användning och klassificering av funktionalitet. Kravspecifikationen bör, enligt ramverket, även innehålla en systemöversikt, kommersiella och leverantörsrelaterade krav, design- och arkitektoniska krav samt utförandekrav. Ramverket har prövats och vidareutvecklats utifrån en extern validering i form av en utvärderingsworkshop där ramverkets relevans och användbarhet diskuterats utifrån de erfarenheter och den dokumentation som genererats i Landstinget i Värmland.
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| 2. |
- Ryberg, Anders, 1973-
(author)
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Camera Modelling and Calibration with Machine Vision Applications
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Camera modelling and calibration are important parts of machine vision. They can be used for calculating geometric information from images. A camera model is a mathematical projection between a 3D object space and a 2D image. The camera calibration is a mathematical procedure calculating parameters of the camera model, usually based on several images of reference points. These fundamental parts of machine vision are improved in this thesis. One large part is the development of a generic camera model, GCM, that is accurate, computationally efficient and can be used for both conventional, fisheye and even catadioptric cameras. Different models were used in the past for conventional and omnidirectional cameras and this is a well-known problem, the solution of which is described in this thesis. The accuracy of camera models is improved by introducing new ways of compensating for different distortions, such as radial istortion, varying entrance pupil point and decentring distortion. Calibration is mproved by introducing newmeans of calculating start estimates of camera parameters, from analysing shapes, sizes and positions of the reference points in the images. These start estimates are needed in order to make the calibration converge. Methods for calculating better reference centre points than the centres of gravity are developed in order to increase the accuracy further. Non-trivial null spaces that occur during calibration are identified. Awareness of these improve the calibration. Calibrations with different camera models are implemented and tested for real cameras in order to compare their accuracy. Certain models are better for certain situations, but the overall performance and properties are favourable for the GCM. A stereo vision welding robot system is developed, using the new model. It determines the geometry of a 3D weld joint, so that a robot can follow it. The same system is implemented in a virtual environment using a simulation software. Such simulation is important since it makes it possible to develop robot vision systems off-line.
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| 3. |
- Andersson, Annika, et al.
(author)
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Comparison between automatic ribotyping and random amplified polymorphic DNA analysis of Bacillus cereus isolates from the dairy industry
- 1998
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In: International journal of food microbiology. - 0346-718X. ; 47:1-2, s. 147-51
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Journal article (peer-reviewed)abstract
- Discrimination by automatic ribotyping and random amplified polymorphic DNA PCR, RAPD, was compared for 40 different B. cereus dairy isolates, 4 different B. mycoides isolates and 6 culture collection strains. RAPD-PCR has previously shown to be useful for tracing contamination routes of B. cereus to milk. Automatic ribotyping using EcoRI and PvuII separated the B. cereus and B. mycoides isolates/strains into 36 different ribotypes. RAPD-typing with primer 1 (5?-CCGAGTCCA-3?) and primer 2 (5?-CCGGCGGCG-3?) generated 40 different RAPD-profiles. However, 17 isolates clustered into 8 groups, irrespective of the primer and restriction enzyme used and in all but one case, the isolates with the same pattern were isolated from the same dairy. To conclude RAPD-typing was only slightly more discriminatory than automatic ribotyping and therefore automatic ribotyping proved to be a useful, standardized and quick method to discriminate between B. cereus strains. As the two methods are based on completely different genetic properties, one of the methods can be used to confirm the results from the other method, when identity among isolates needs to be verified.
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| 4. |
- Bergkvist, Linda, 1979-
(author)
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Towards a Framework for Relational-Oriented Management of Information Systems Outsourcing : Key Conditions Connected to Actors, Relationships and Process
- 2014
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Doctoral thesis (other academic/artistic)abstract
- Currently, client and supplier firms are struggling with how they can make their information systems (IS) outsourcing engagements more valuable. This research points to the importance of successful practice and outcome in IS outsourcing for achieving engagements of value. To enhance the understanding of IS outsourcing over time, a process perspective is applied. Further, this research is based on the contention that IS outsourcing is more likely to be successful if challenges are managed in a proactive manner and with a relationship perspective. Thus, understanding challenges in IS outsourcing requires a symmetric view on client and supplier.The thesis is based on two studies presented as three steps of research: development, validation and reconsideration of a conceptual framework. The licentiate study centred on the step of development whereas the present doctoral study has a focus on the steps of validation and reconsideration. The purpose of this study includes investigating how the management of successful practice and outcome in IS outsourcing can be enabled. To address the purpose, the IS outsourcing process is studied in a client–supplier relationship. This includes that different actor perspectives, including strategic, operative, and systems, are considered for a better understanding of the practice of IS outsourcing, the challenges, and how different actors convey successful IS outsourcing.The thesis contributes a framework for relational-oriented management of IS outsourcing, which provides the structure for understanding what needs to be managed in terms of key conditions, when and how in connection to actors, relationships, and process. Theoretical propositions, enhancing the understanding of the complexity of IS outsourcing as well as the number of challenges involved, are also presented. In brief, these propositions relate to the circumstance that IS outsourcing requires management on different levels and with different kinds of results in mind.
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| 5. |
- Bjorklund, Robert, et al.
(author)
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Electrode specific information from voltammetric monitoring of biogas production
- 2010
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In: Talanta. - : Elsevier Science B.V., Amsterdam.. - 0039-9140 .- 1873-3573. ; 81:04-May, s. 1578-1584
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Journal article (peer-reviewed)abstract
- A sensor employing pulse voltammetry monitored the liquid phase of a biogas reactor during 32 days of gas production An electrode allay consisting of stainless steel, platinum and rhodium electrodes generated current responses for a sequence of voltage pulses Plots of individual current responses against time indicated the electrochemical changes occurring in the broth from the perspective of each electrode. The responses from stainless steel had a pronounced diurnal oscillation which followed the daily introduction and consumption of substrate The current responses for platinum were in a narrow range whereas those for rhodium exhibited several minima A disturbance in the reactor caused by omission of substrate led to decreases in both gas production and current responses for all the electrodes Multivariate data evaluation of all the current responses by principal component analysis indicated the daily fluctuations for concentrations of ions and redox active compounds in the broth
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| 6. |
- Christiansson, Lennart, et al.
(author)
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A new method of intrathecal PO2, PCO2, and pH measurements for continuous monitoring of spinal cord ischemia during thoracic aortic clamping in pigs
- 2000
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In: Surgery. - : Elsevier BV. - 0039-6060 .- 1532-7361. ; 127:5, s. 571-576
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Journal article (peer-reviewed)abstract
- BACKGROUND: Impaired spinal cord circulation during thoracic aortic clamping may result in paraplegia. Reliable and fast responding methods for intraoperative monitoring are needed to facilitate the evaluation of protective measures and efficiency of revascularization.METHODS: In 11 pigs, a multiparameter PO2, PCO2, and pH sensor (Paratrend 7, Biomedical Sensors Ltd, United Kingdom) was introduced into the intrathecal space for continuous monitoring of cerebrospinal fluid (CSF) oxygenation during thoracic aortic cross-clamping (AXC) distal to the left subclavian artery. A laser-Doppler probe was inserted into the epidural space for simultaneous measurements of spinal cord flux. Registrations were made before and 30 minutes after clamping and 30 and 60 minutes after declamping. The same measuring points were used for systemic hemodynamic and metabolic data acquisition.RESULTS: The mean CSF PO2 readings of 41 mm Hg (5.5 kPa) at baseline decreased within 3 minutes to 5 mm Hg (0.7 kPa) during AXC (P < .01). Spinal cord flux measurement responded immediately in the same way to AXC. Both methods indicated normalization of circulation during declamping. Significant (P < .01) changes were also observed in the CSF metabolic parameters PCO2 and pH.CONCLUSIONS: In this experimental model of spinal ischemia by AXC, online monitoring of intrathecal PO2, PCO2, and pH showed significant changes and correlated well with epidural laser-Doppler flowmetry (P < .01).
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| 7. |
- Christiansson, Lennart, et al.
(author)
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Aspects of the spinal cord circulation as assessed by intrathecal oxygen tension monitoring during various arterial interruptions in the pig
- 2001
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In: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 121:4, s. 762-772
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Journal article (peer-reviewed)abstract
- OBJECTIVE: We sought to study the effect of various modes of interruption of the spinal cord blood supply on intrathecal oxygenation.METHODS: In 24 pigs intrathecal PO (2), PCO (2), and pH were continuously monitored with a multiparameter catheter (Paratrend 7, Biomedical Sensors; Diametrics Medical, Inc, St Paul, Minn) during and after aortic crossclamping or selective interruption of segmental arteries and proximal collateral circulation.RESULTS: Proximal aortic clamping (n = 6) produced complete ischemia, whereas a second clamp close to the celiac trunk (n = 4) partly protected against spinal cord ischemia. This is explained by prevention of the steal phenomenon in the excluded part of the aorta. Adding clamps to the subclavian arteries (n = 6) created complete spinal ischemia as the collateral circulation was interrupted. In another group (n = 4) all segmental arteries below T5 were occluded with no reaction in the intrathecal variables. Additional selective clamping of supreme intercostal arteries (n = 4) showed the relative importance of the subclavian and vertebral collateral pathways.CONCLUSIONS: Continuous intrathecal PO (2) was monitored during various modes of interruption of the spinal cord blood supply. This provided insight into the ischemia mechanisms and relative importance of the segmental contribution and proximal collateral pathways of the spinal cord circulation in pigs. A short literature review is given, and aspects of comparative anatomy are discussed.
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| 8. |
- Christiansson, Lena, et al.
(author)
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Expanding environmental Perspectives
- 1994
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In: Expanding environmental perspectives : lessons of the past, prospects for the future. - 917966279X ; , s. 119-142
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Book chapter (other academic/artistic)
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| 9. |
- Christiansson, Lennart, et al.
(author)
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Increased FiO2 improves intrathecal oxygenation during thoracic aortic cross-clamping in pigs
- 2001
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In: Scandinavian Cardiovascular Journal. - 1401-7431 .- 1651-2006. ; 35:2, s. 147-150
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To investigate the effect of 100% oxygen ventilation on cerebrospinal fluid (CSF) oxygenation in 11 pigs during thoracic aortic cross-clamping.DESIGN: An aorto-aortic shunt was used for control of central hemodynamics and study of hypoperfusion by exsanguination. CSF PO2, PCO2 and pH were continuously monitored before and during clamping. The changes in hemodynamic parameters and intrathecal gas tensions in response to variations in proximal mean aortic pressure and fraction of inspired oxygen (FiO2) were recorded.RESULTS: Baseline CSF PO2 decreased from 4.8 +/- 1.9 to 2.6 +/- 2.2 kPa following aortic occlusion. Increasing FiO2 to 1.0 resulted in a significant increase in CSF PO2 to 4.1 +/- 3.0 with a return to 2.7 +/- 2.1 kPa after reducing FiO2 to 0.4 again. The same variations in FiO2 did not induce any significant changes in CSF PO2 during hypotension.CONCLUSION: Increased FiO2 during experimental thoracic aortic cross-clamping with stable proximal arterial pressure helps to maintain CSF PO2, whereas severe hypotension could not be compensated for by hyperoxemia.
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| 10. |
- Christiansson, Lennart, et al.
(author)
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Relationship between intrathecal oxygen tension and ultrastructural changes in the spinal cord during experimental aortic clamping
- 2000
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In: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 19:4, s. 413-420
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To investigate spinal cord ultrastructure related to cerebrospinal fluid (CSF) oxygenation.DESIGN: experimental aortic occlusion model with intrathecal oxygen tension monitoring.MATERIALS AND METHODS: Two groups of pigs underwent proximal (P) or double (D) aortic occlusion for 30 min followed by 1 h of reperfusion. In a third group (I) segmental arteries distal to T3 were clamped for 90 min. A thin pO(2), pCO(2) and pH sensor was placed intrathecally for continuous monitoring of CSF. Spinal cord segments were studied by electron microscopy (EM).RESULTS: In group P, CSF-pO(2)rapidly decreased during clamping and major changes in pH and pCO(2)were seen. EM demonstrated neuronal degeneration with loss of cellular integrity and severe affection of organelles. In the group D, CSF oxygenation decreased to about half, but with only moderate changes in the metabolic parameters. Group I showed no significant changes in CSF measurements. The latter groups were similar at EM, showing only mild mitochondrial changes.CONCLUSIONS: The level of CSF oxygenation during aortic cross-clamping or segmental artery interruption seems to correlate with ultrastructural changes in the spinal cord. This online intrathecal monitoring technique may provide valuable information on spinal cord circulation during thoracoabdominal aortic surgery.
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