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- Tahvili, Sahar
(författare)
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A Decision Support System for Integration Test Selection
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Software testing generally suffers from time and budget limitations. Indiscriminately executing all available test cases leads to sub-optimal exploitation of testing resources. Selecting too few test cases for execution on the other hand might leave a large number of faults undiscovered. Test case selection and prioritization techniques can lead to more efficient usage of testing resources and also early detection of faults. Test case selection addresses the problem of selecting a subset of an existing set of test cases, typically by discarding test cases that do not add any value in improving the quality of the software under test. Test case prioritization schedules test cases for execution in an order to increase their effectiveness at achieving some performance goals such as: earlier fault detection, optimal allocation of testing resources and reducing overall testing effort. In practice, prioritized selection of test cases requires the evaluation of different test case criteria, and therefore, this problem can be formulated as a multi-criteria decision making problem. As the number of decision criteria grows, application of a systematic decision making solution becomes a necessity. In this thesis, we propose a tool-supported framework using a decision support system, for prioritizing and selecting integration test cases in embedded system development. The framework provides a complete loop for selecting the best candidate test case for execution based on a finite set of criteria. The results of multiple case studies, done on a train control management subsystem from Bombardier Transportation AB in Sweden, demonstrate how our approach helps to select test cases in a systematic way. This can lead to early detection of faults while respecting various criteria. Also, we have evaluated a customized return on investment metric to quantify the economic benefits in optimizing system integration testing using our framework.
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- Pitti, Helda, et al.
(författare)
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Cerebrovascular damage in subjective cognitive decline : A systematic review and meta-analysis
- 2022
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Ingår i: Ageing Research Reviews. - : Elsevier Ireland Ltd. - 1568-1637 .- 1872-9649. ; 82
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Tidskriftsartikel (refereegranskat)abstract
- Background: Subjective cognitive decline (SCD) has been postulated as an early marker of Alzheimer’s Disease (AD) but it can also be associated to other non-AD pathologies such as Vascular Dementia (VaD). Nevertheless, there is scarce data about SCD as a potential harbinger of cerebrovascular pathology. Thus, we conducted a systematic review and meta-analysis on the association between SCD and cerebrovascular damage measured by neuroimaging markers.Method: This study was performed following the PRISMA guidelines. The search was conducted in 3 databases (PubMed, Scopus and Web of Science) from origin to December 8th, 2021. Primary studies including cognitively unimpaired adults with SCD and neuroimaging markers of cerebrovascular damage (i.e., white matter signal abnormalities, WMSA) were selected. Qualitative synthesis and meta-analysis of studies with a case-control design was performed.Results: Of 241 articles identified, 21 research articles were selected. Eight case-control studies were included for the meta-analysis. A significant overall effect-size was observed for the mean WMSA burden in SCD relative to controls, where the WMSA burden was higher in SCD.Conclusion: Our findings show the potential usefulness of SCD as a harbinger of cerebrovascular disease in cognitively healthy individuals. Further research is needed in order to elucidate the role of SCD as a preclinical marker of vascular cognitive impairment.
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- Soini, Ylermi, et al.
(författare)
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Claudins 1, 11 and twist in meningiomas
- 2010
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Ingår i: Histopathology. - : Wiley. - 0309-0167 .- 1365-2559. ; 56:6, s. 821-824
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Tidskriftsartikel (refereegranskat)
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- Tahvildari, Babak, et al.
(författare)
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Switching between on and off states of persistent activity in lateral entorhinal layer III neurons
- 2007
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Ingår i: Hippocampus. - : Wiley. - 1050-9631 .- 1098-1063. ; 17:4, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- Persistent neural spiking maintains information during a, working memory task when a stimulus is no longer present. During I retention, this activity needs to be stable to distractors. More importantly, when retention is no longer relevant, cessation of the activity is necessary to enable processing and retention of subsequent information. Here, by means of intracellular recording with sharp microelectrode in in vitro rat brain slices, we demonstrate that single principal layer III neurons of the lateral entorhinal cortex (EC) generate persistent spiking activity with a novel ability to reliably toggle between spiking activity and a silent state. Our data indicates that in the presence of muscarmic receptor activation, persistent activity following an excitatory input may be induced and that a subsequent excitatory input can terminate this activity and cause the neuron to return to a silent state. Moreover, application of inhibitory hyperpolarizing stimuli is neither able to decrease the frequency of the persistent activity nor terminate it. The persistent activity can also be initiated and terminated by synchronized synaptic stimuli of layer II/III of the perirhinal cortex. The neuronal ability to switch On and Off persistent activity may facilitate the concurrent representation of temporally segregated information arriving in the EC and being directed toward the hippocampus.
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- Cabanettes, Frédéric, 1982-
(författare)
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Cam Roller Contact : The topographical aspect
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The automotive industry and the design of engines are strongly ruled by performance and legislation demands. First order aspects defining the main functions of a component are well known and new challenges appear at a lower scale. Wear reduction is defined as a second order problem and requires decreasing the scale of observation of components down to roughness. This thesis work and its aim lie within the scope of wear improvements and are focused on the injection cam/roller contact of heavy duty diesel engines. In order to reach the aim several material and methods are used: a valve train rig test, roughness characterisation and different manufacturing processes. It is shown by experiments that the flank and nose of injection cams are specific areas with specific roughness (higher density of summits Sds) compared to the rest of the cam. The wear is characterized by rounded-off of summits (Ssc). From those results and since wear processes are strongly linked to the pressure generated between the mating surfaces, the development of a rough contact model is of great interest. An elastic rough contact model is implemented and improved later on by an elasto-plastic description of materials. The simulations are validated by a wear test and are used to rank the ability of surfaces (both cam and roller) to face wear problems. The ratio of plastically deformed peaks shows that the flank and nose of the cam are reacting badly to pressures. Additionally the rough contact allows ranking/optimization of different machining processes with respect to their expected functional contact performance. Future work will be to use such a model to choose a good combination of surfaces (cam and roller) in order to reduce wear.
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- Ciavarella, Michele, et al.
(författare)
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Rolling of a cylinder with slip-dependent friction: The Carter solution revisited
- 2022
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Ingår i: Theoretical and Applied Fracture Mechanics. - : Elsevier BV. - 0167-8442. ; 121
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Tidskriftsartikel (refereegranskat)abstract
- The problem of a wheel under tractive rolling of Carter is revisited here by assuming a slip-dependent friction force. By assuming a change from static to dynamic friction coefficient occurs over a small distance, we develop effectively a fracture mechanics solution for the shear tractions, which describes some aspects of “falling friction” creepage forces which are commonly observed experimentally. Possible agreement with experiments is discussed, suggesting that friction may include also rate-dependent effects. A simple strip theory is used to estimate 3D effects, which reduce the strength of the singularity at the edges being the peak pressure lower there.
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- Emmitt, Stephen, 1961-
(författare)
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Research processes and practicalities
- 2013. - 1
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Ingår i: Architectural Technology. - Chichester, West Sussex : Wiley-Blackwell. - 9781118292068 - 1118292065 ; , s. 231-246
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Bokkapitel (refereegranskat)
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- Islander, Gunilla
(författare)
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In vitro contracture testing for the diagnosis of malignant hyperthermia susceptibility
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Malignant hyperthermia (MH) susceptibility is a rare inherited muscular disorder, which may cause a lethal increase in metabolism during anaesthesia with certain commonly used anaesthetic. Susceptible individuals are without any signs or symptoms. It is important to identify individuals at risk, since the MH reaction is preventable. Susceptibility to MH is diagnosed with an in vitro contracture test (IVCT) performed on viable skeletal muscle. The muscle is exposed to halothane/caffeine in an organ bath. An increase in baseline tension >=0.2g is abnormal. There have been few thorough validations of the IVCT and false diagnoses do occur, which make genetic research difficult. We have investigated 1) the reliability of a negative diagnosis, 2) the inheritance pattern suggested by IVCT and 3) the validation the IVCT results in 706 patients in 175 families. Fourteen patients diagnosed MH negative revealed no signs of MH when exposed to anaesthetics known to cause MH. Judged from outcome of IVCT in 101 families, there is more than one mode of inheritance. The IVCT was validated with comparisons within and between laboratories, between different types of tests and within and between monozygotic twins. We found that increase in baseline tension exceeding 0.5g were almost always reproducible within and between laboratories, between different types of tests and within and between monozygotic twins. Our conclusions are that 1. There are no indications of false negative diagnoses. 2. There could be more than one mode of inheritance. 3. For scientific purposes when a high specificity is needed the threshold could be increased to 0.5g. However the clinical diagnostic cut off limits should be unchanged.
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- Locke Grandér, Barbara
(författare)
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Natural Varroa mite-surviving Apis mellifera honeybee populations
- 2016
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Ingår i: Apidologie. - : Springer Science and Business Media LLC. - 0044-8435 .- 1297-9678. ; 47, s. 467-482
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Forskningsöversikt (refereegranskat)abstract
- The Varroa destructor mite is the largest threat to apiculture worldwide and has been responsible for devastating losses of wild honeybee populations in Europe and North America. However, Varroa mite-resistant populations of A. mellifera honeybees have been reported and documented around the world with a variety of explanations for their long-term survival with uncontrolled mite infestation. This review synthesizes the work on naturally occurring survival to Varroa mites and discusses what these honeybee populations can signify for apiculture.
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- Lodhi, Abdulaziz, 1945-
(författare)
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Monsoon Reflexions
- 2017
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Bok (populärvet., debatt m.m.)
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- Lodhi, Abdulaziz Yusuf, et al.
(författare)
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African Islam in Tanzania
- 1999
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Ingår i: Islam Outside The Arab World. - : Curzon, Richmond. - 0700711244 ; , s. 97-110
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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- Maier, O., et al.
(författare)
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ISLES 2015-A public evaluation benchmark for ischemic stroke lesion segmentation from multispectral MRI
- 2017
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Ingår i: Medical Image Analysis. - : Elsevier BV. - 1361-8415 .- 1361-8423. ; 35, s. 250-269
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic stroke is the most common cerebrovascular disease, and its diagnosis, treatment, and study relies on non-invasive imaging. Algorithms for stroke lesion segmentation from magnetic resonance imaging (MRI) volumes are intensely researched, but the reported results are largely incomparable due to different datasets and evaluation schemes. We approached this urgent problem of comparability with the Ischemic Stroke Lesion Segmentation (ISLES) challenge organized in conjunction with the MICCAI 2015 conference. In this paper we propose a common evaluation framework, describe the publicly available datasets, and present the results of the two sub-challenges: Sub-Acute Stroke Lesion Segmentation (SISS) and Stroke Perfusion Estimation (SPES). A total of 16 research groups participated with a wide range of state-of-the-art automatic segmentation algorithms. A thorough analysis of the obtained data enables a critical evaluation of the current state-of-the-art, recommendations for further developments, and the identification of remaining challenges. The segmentation of acute perfusion lesions addressed in SPES was found to be feasible. However, algorithms applied to sub-acute lesion segmentation in SISS still lack accuracy. Overall, no algorithmic characteristic of any method was found to perform superior to the others. Instead, the characteristics of stroke lesion appearances, their evolution, and the observed challenges should be studied in detail. The annotated ISLES image datasets continue to be publicly available through an online evaluation system to serve as an ongoing benchmarking resource (www.isles-challenge.org).
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- Maier, Petra, et al.
(författare)
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Corrosion Rates by Immersion and Calorimetry on the Example of Extruded Mg10Gd(1Nd)1La
- 2024
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Ingår i: Magnesium Technology 2024. - 2367-1696 .- 2367-1181. - 9783031502392 ; , s. 35-39
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Konferensbidrag (refereegranskat)abstract
- This study is a follow-up investigation of the influence of the alloying elements Nd and La on the corrosionCorrosionby immersionImmersion of an extruded and heat-treated Mg10Gd. The previous study made clear that the age-hardened condition has the lowest corrosion rateCorrosion Rate but high pitting corrosionPitting corrosion susceptibility. The extruded Mg10Gd(1Nd)1La shows the lowest pitting factors based on severe corrosion. In this study, the corrosionCorrosion morphology and corrosion rates are discussed based on calorimetric data and 3D-analysis by µCT and compared to the results from the immersion tests. Thermal power and enthalpy readings from the isothermal calorimetryCalorimetry offer information on the reaction kinetics. The corrosion rateCorrosion Rate values are discussed based on the evaluation method—in general agreement alloying with Nd reduces the corrosion rateCorrosion Rate. The pitting factor is found to be very dependent on the reference average penetration: weight or volume loss, or evaluation by 3D volume or by 2D cross-sections.
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- Maier, Petra, et al.
(författare)
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Different Analytical Methods to Determine the Influence of Pitting on the Residual Performance of Mg Alloys as Implant Materials
- 2024
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Ingår i: Magnesium Technology 2024. - 2367-1696 .- 2367-1181. - 9783031502392 ; , s. 3-5
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Konferensbidrag (refereegranskat)abstract
- Mg alloys are prone to pitting due to their non-uniform protective corrosionCorrosion layers, which can lead to an increase in stress intensity based on the notch effect, pit-to-crack transition, and thus premature failure. A small set of analytical methods to determine the extent of pitting and its effect on the resulting residual strengthResidual tensile strength is presented. Micrographs, 3D microscopy, or 3D analysis using CT are used to determine the amount and geometry of pitting—each with advantages and disadvantages. The influence of the corrosion pits on the mechanical propertiesMechanical Properties is tested by static, quasi-static, and cyclic test methods: by tensile, flexural, or fatigueFatigue testing—either after corrosionCorrosion or overlapping. Knowledge about the critical pit is of general interest. Stress corrosion is discussed by applying static tests like C-ring testing, which also plays a role in slow strain rate tensile testsTensile test and stress corrosion cracking is more or less influenced by corrosion pits.
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