| 1. |
- Locke, Adam E, et al.
(författare)
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Genetic studies of body mass index yield new insights for obesity biology.
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 518:7538, s. 197-401
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P < 5 × 10(-8)), 56 of which are novel. Five loci demonstrate clear evidence of several independent association signals, and many loci have significant effects on other metabolic phenotypes. The 97 loci account for ∼2.7% of BMI variation, and genome-wide estimates suggest that common variation accounts for >20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.
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| 2. |
- Shungin, Dmitry, et al.
(författare)
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New genetic loci link adipose and insulin biology to body fat distribution.
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 518:7538, s. 187-378
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Tidskriftsartikel (refereegranskat)abstract
- Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms.
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| 3. |
- Surendran, Praveen, et al.
(författare)
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Trans-ancestry meta-analyses identify rare and common variants associated with blood pressure and hypertension
- 2016
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 48:10, s. 1151-1161
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Tidskriftsartikel (refereegranskat)abstract
- High blood pressure is a major risk factor for cardiovascular disease and premature death. However, there is limited knowledge on specific causal genes and pathways. To better understand the genetics of blood pressure, we genotyped 242,296 rare, low-frequency and common genetic variants in up to 192,763 individuals and used -1/4155,063 samples for independent replication. We identified 30 new blood pressure- or hypertension-associated genetic regions in the general population, including 3 rare missense variants in RBM47, COL21A1 and RRAS with larger effects (>1.5 mm Hg/allele) than common variants. Multiple rare nonsense and missense variant associations were found in A2ML1, and a low-frequency nonsense variant in ENPEP was identified. Our data extend the spectrum of allelic variation underlying blood pressure traits and hypertension, provide new insights into the pathophysiology of hypertension and indicate new targets for clinical intervention.
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| 4. |
- Kapoor, Pooja Middha, et al.
(författare)
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Combined associations of a polygenic risk score and classical risk factors with breast cancer risk
- 2021
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 113:3, s. 329-337
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated the joint associations between a new 313-variant PRS (PRS313) and questionnaire-based breast cancer risk factors for women of European ancestry, using 72 284 cases and 80 354 controls from the Breast Cancer Association Consortium. Interactions were evaluated using standard logistic regression and a newly developed case-only method for breast cancer risk overall and by estrogen receptor status. After accounting for multiple testing, we did not find evidence that per-standard deviation PRS313 odds ratio differed across strata defined by individual risk factors. Goodness-of-fit tests did not reject the assumption of a multiplicative model between PRS313 and each risk factor. Variation in projected absolute lifetime risk of breast cancer associated with classical risk factors was greater for women with higher genetic risk (PRS313 and family history) and, on average, 17.5% higher in the highest vs lowest deciles of genetic risk. These findings have implications for risk prevention for women at increased risk of breast cancer.
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| 5. |
- Ried, Janina S., et al.
(författare)
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A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.
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| 6. |
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| 7. |
- Lehikoinen, Aleksi, et al.
(författare)
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Declining population trends of European mountain birds
- 2019
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 25:2, s. 577-588
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Tidskriftsartikel (refereegranskat)abstract
- Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south-western (Iberia) and south-central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (−7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant −10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations.
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| 8. |
- McKay, James D., et al.
(författare)
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Large-scale association analysis identifies new lung cancer susceptibility loci and heterogeneity in genetic susceptibility across histological subtypes
- 2017
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 49:7, s. 1126-1132
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Tidskriftsartikel (refereegranskat)abstract
- Although several lung cancer susceptibility loci have been identified, much of the heritability for lung cancer remains unexplained. Here 14,803 cases and 12,262 controls of European descent were genotyped on the OncoArray and combined with existing data for an aggregated genomewide association study (GWAS) analysis of lung cancer in 29,266 cases and 56,450 controls. We identified 18 susceptibility loci achieving genome-wide significance, including 10 new loci. The new loci highlight the striking heterogeneity in genetic susceptibility across the histological subtypes of lung cancer, with four loci associated with lung cancer overall and six loci associated with lung adenocarcinoma. Gene expression quantitative trait locus (eQTL) analysis in 1,425 normal lung tissue samples highlights RNASET2, SECISBP2L and NRG1 as candidate genes. Other loci include genes such as a cholinergic nicotinic receptor, CHRNA2, and the telomere-related genes OFBC1 and RTEL1. Further exploration of the target genes will continue to provide new insights into the etiology of lung cancer.
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| 9. |
- Skovsted, Christian B., et al.
(författare)
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Early Cambrian record of failed durophagy and shell repair in an epibenthic mollusc
- 2007
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 3:3, s. 314-317
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Tidskriftsartikel (refereegranskat)abstract
- Predation is arguably one of the main driving forces of early metazoan evolution, yet the fossil record of predation during the Ediacaran–Early Cambrian transition is relatively poor. Here, we present direct evidence of failed durophagous (shell-breaking) predation and subsequent shell repair in the Early Cambrian (Botoman) epibenthic mollusc Marocella from the Mernmerna Formation and Oraparinna Shale in the Flinders Ranges, South Australia. This record pushes back the first appearance of durophagy on molluscs by approximately 40 Myr.
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| 10. |
- Arts, Thomas, 1969, et al.
(författare)
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Testing Implementations of Formally Verified Algorithms
- 2005
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Ingår i: Proceedings of the 5th Conference on Software Engineering Research and Practice in Sweden.
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Konferensbidrag (refereegranskat)abstract
- Algorithms described in literature can often be used to solvepractical, industrial problems. In safety-critical industrialsettings, algorithms that have been formally verified should be evenmore attractive candidates for implementations. Nevertheless, weobserve little transfer of algorithms from research papers intoproducts. In this paper we describe a case study on the implementationof algorithms for the widely known and broadly studied problem ofleader election. Despite thousands of articles on that topic, itstill requires a lot of engineering to select the relevant articles,and get a correct algorithm implemented in an industrial setting.Modifications are necessary to meet all requirements. We proposeadaptation and testing of formal properties as a realistic and cheap way tocheck the correctness of the modifications, since performing a formalproof seems unrealistic for industrial systems. We show how we use theproperties stated in the articles to guide our tests.
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| 11. |
- Blomstrand, Peter, et al.
(författare)
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Left ventricular diastolic function, assessed by echocardiography and tissue Doppler imaging, is a strong predictor of cardiovascular events, superior to global left ventricular longitudinal strain, in patients with type 2 diabetes
- 2015
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Ingår i: European Heart Journal Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 16:9, s. 1000-1007
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The aim of the study was to determine whether left ventricular systolic function, in terms of global left ventricular longitudinal strain (GLS), and diastolic function, expressed as the ratio between early diastolic transmitral flow and mitral annular motion velocities (E/e'), can predict cardiovascular events in patients with diabetes mellitus type 2.Methods and results: We prospectively investigated 406 consecutive patients, aged 55-65 years, with diabetes mellitus, who participated in the CARDIPP study. Echocardiography, pulse pressure (pp), and glycosylated haemoglobin (HbA1c) were analysed. Twelve cases of myocardial infarction and seven cases of stroke were identified during the follow-up period of 67 +/- 17 months. Univariate Cox regression analysis showed that E/e' was a strong predictor of cardiovascular events (hazards ratio 1.12; 95% confidence interval 1.06-1.18, P < 0.001). E/e' was prospectively associated with cardiovascular events independent of age, sex, GLS, left ventricular ejection fraction (LVEF), pp, and HbA1c in multivariate analysis. Receiver operating characteristic curves showed that E/e' and HbA1c were the strongest predictors for cardiovascular events, both having an area under the curve (AUC) of 0.71 followed by LVEF with an AUC of 0.65 and GLS of 0.61. In a Kaplan-Meyer analysis, the cumulative probability of an event during the follow-up period was 8.6% for patients with an E/e' ratio >15 compared with 2.6% for patients with E/e' <= 15, P = 0.011.Conclusion: In middle-aged patients with type 2 diabetes, E/e' is a strong predictor of myocardial infarction and stroke, comparable with HbA1c and superior to GLS and LVEF.
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| 12. |
- Bradter, Ute, et al.
(författare)
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Decomposing the spatial and temporal effects of climate on bird populations in northern European mountains
- 2022
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:21, s. 6209-6227
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Tidskriftsartikel (refereegranskat)abstract
- The relationships between species abundance or occurrence versus spatial variation in climate are commonly used in species distribution models to forecast future distributions. Under “space-for-time substitution”, the effects of climate variation on species are assumed to be equivalent in both space and time. Two unresolved issues of space-for-time substitution are the time period for species' responses and also the relative contributions of rapid- versus slow reactions in shaping spatial and temporal responses to climate change. To test the assumption of equivalence, we used a new approach of climate decomposition to separate variation in temperature and precipitation in Fennoscandia into spatial, temporal, and spatiotemporal components over a 23-year period (1996–2018). We compiled information on land cover, topography, and six components of climate for 1756 fixed route surveys, and we modeled annual counts of 39 bird species breeding in the mountains of Fennoscandia. Local abundance of breeding birds was associated with the spatial components of climate as expected, but the temporal and spatiotemporal climatic variation from the current and previous breeding seasons were also important. The directions of the effects of the three climate components differed within and among species, suggesting that species can respond both rapidly and slowly to climate variation and that the responses represent different ecological processes. Thus, the assumption of equivalent species' response to spatial and temporal variation in climate was seldom met in our study system. Consequently, for the majority of our species, space-for-time substitution may only be applicable once the slow species' responses to a changing climate have occurred, whereas forecasts for the near future need to accommodate the temporal components of climate variation. However, appropriate forecast horizons for space-for-time substitution are rarely considered and may be difficult to reliably identify. Accurately predicting change is challenging because multiple ecological processes affect species distributions at different temporal scales.
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| 13. |
- Burdess, Anne, et al.
(författare)
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Early Experience With a Novel Dissection-Specific Stent-Graft to Prevent Distal Stent-Graft-Induced New Entry Tears After Thoracic Endovascular Repair of Chronic Type B Aortic Dissections
- 2022
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Ingår i: Annals of Vascular Surgery. - : Elsevier. - 0890-5096 .- 1615-5947. ; 81, s. 36-47
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aim was to report short and mid-term outcomes of a novel, investigational, dissection-specific stent-graft (DSSG), specifically designed to address the features of chronic type B aortic dissection (CTBAD) and reduce the risk of distal stent-graft-induced new entry tears (dSINE).Materials and Methods: A retrospective single center cohort study of all patients undergoing TEVAR with the DSSG for CTBAD from January 1, 2017 to January 31, 2020. The DSSG, which is a modified stent-graft based on the Cook Zenith Alpha Thoracic platform, has no proximal barbs, and a customized longer body length with substantial taper. The second and third distal Z-stents are sited internally to avoid any contact of the metal skeleton with the dissection membrane and have reduced radial force, while the most distal stent was removed creating a distal 30 mm unsupported Dacron graft.Results: Sixteen patients (13 males, 3 females) with a median age of 66 years (range 31–79 years) underwent elective TEVAR of CTBAD using the DSSG. Six patients (38%) had an underlying connective tissue disorder. The median tapering was 10 mm (range 4 mm–21 mm) and median length 270 mm (range 210–380 mm). Technical success was achieved in all but one case (96%). One patient died within 30 days, due to retrograde type A dissection with cardiac tamponade. The 30-day rate of stroke, spinal cord ischemia, and re-interventions was 0%. After median imaging follow-up time of 17 months (range 1–31 months), one patient developed a dSINE 4 months after the index procedure. After median survival follow-up of 23 months (range 2–35 months), one late death occurred due to traumatic brain injury, while no aortic-related death occurred during follow-up. Complete false lumen (FL) thrombosis was achieved in 9 patients while the remaining 6 showed partial FL thrombosis. No instances of diameter increase at the level oftreated aortic segment were noted with serial measurements showing either stable (n = 7) or decreased (n = 8) maximal transverse diameter.Conclusions: Use of a novel DSSG with low radial force for TEVAR in the setting of CTBAD is safe and feasible. This early real-world experience shows promising mid-term effectiveness with low rates of dSINE or unplanned re-interventions and satisfactory aortic remodeling during follow-up. Longer follow-up is needed, however, before any firm conclusions can be drawn.
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| 14. |
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| 15. |
- Cantwell, John, et al.
(författare)
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McGee's Counterexample to the Ramsey Test
- 2017
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Ingår i: Theoria. - : DPHT Stockholm. - 0040-5825 .- 1755-2567. ; 83:2, s. 154-168
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Tidskriftsartikel (refereegranskat)abstract
- Vann McGee has proposed a counterexample to the Ramsey Test. In the counterexample, a seemingly trustworthy source has testified that p and that if not-p, then q. If one subsequently learns not- p (and so learns that the source is wrong about p), then one has reason to doubt the trustworthiness of the source (perhaps even the identity of the source) and so, the argument goes, one has reason to doubt the conditional asserted by the source. Since what one learns is that the antecedent of the conditional holds, these doubts are contrary to the Ramsey Test. We argue that the counterexample fails. It rests on a principle of testimonial dependence that is not applicable when a source hedges his or her claims.
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| 16. |
- Couet, Joséphine, et al.
(författare)
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Short-lived species move uphill faster under climate change
- 2022
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 198:4, s. 877-888
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is pushing species ranges and abundances towards the poles and mountain tops. Although many studies have documented local altitudinal shifts, knowledge of general patterns at a large spatial scale, such as a whole mountain range, is scarce. From a conservation perspective, studying altitudinal shifts in wildlife is relevant because mountain regions often represent biodiversity hotspots and are among the most vulnerable ecosystems. Here, we examine whether altitudinal shifts in birds’ abundances have occurred in the Scandinavian mountains over 13 years, and assess whether such shifts are related to species’ traits. Using abundance data, we show a clear pattern of uphill shift in the mean altitude of bird abundance across the Scandinavian mountains, with an average speed of 0.9 m per year. Out of 76 species, 7 shifted significantly their abundance uphill. Altitudinal shift was strongly related to species’ longevity: short-lived species showed more pronounced uphill shifts in abundance than long-lived species. The observed abundance shifts suggest that uphill shifts are not only driven by a small number of individuals at the range boundaries, but the overall bird abundances are on the move. Overall, the results underscore the wide-ranging impact of climate change and the potential vulnerability of species with slow life histories, as they appear less able to timely respond to rapidly changing climatic conditions.
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| 17. |
- Cunha, Sara I., et al.
(författare)
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Endothelial ALK1 Is a Therapeutic Target to Block Metastatic Dissemination of Breast Cancer.
- 2015
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Ingår i: Cancer Research. - 1538-7445 .- 0008-5472. ; 75:12, s. 2445-2456
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Tidskriftsartikel (refereegranskat)abstract
- Exploration of new strategies for the prevention of breast cancer metastasis is justifiably at the center of clinical attention. In this study, we combined a computational biology approach with mechanism-based preclinical trials to identify inhibitors of activin-like receptor kinase (ALK) 1 as effective agents for blocking angiogenesis and metastasis in breast cancer. Pharmacologic targeting of ALK1 provided long-term therapeutic benefit in mouse models of mammary carcinoma, accompanied by strikingly reduced metastatic colonization as a monotherapy or part of combinations with chemotherapy. Gene-expression analysis of breast cancer specimens from a population-based nested case-control study encompassing 768 subjects defined endothelial expression of ALK1 as an independent and highly specific prognostic factor for metastatic manifestation, a finding that was corroborated in an independent clinical cohort. Overall, our results suggest that pharmacologic inhibition of endothelial ALK1 constitutes a tractable strategy for interfering with metastatic dissemination of breast cancer. Cancer Res; 75(12); 2445-56. ©2015 AACR.
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| 18. |
- Ebbestad, Jan Ove R., et al.
(författare)
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Predation on bellerophontiform molluscs in the Palaeozoic
- 2009
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Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 42:4, s. 469-485
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Tidskriftsartikel (refereegranskat)abstract
- Shell repair assumed to result from failed predation is documented in 66 specimens of Ordovician-Carboniferous bellerophontiform tergomyan and gastropod molluscs to examine the relationship between the distribution and appearance of injuries, shell morphology and the internal anatomy of the molluscs, as well as the attack strategies of the presumed predators. Furthermore, the distribution of repaired injuries from failed attacks along the apertural margin as a reflection of the nature of the margin and emarginations is investigated. Bellerophontiform molluscs are ideal for this study because of their distinctive isostrophic morphology and the possibility to directly compare broad and narrow conchs with either deep or shallow medial emarginations. The results show that taxa with a deep medial emargination in the form of a slit have significantly more medial injuries than lateral ones. Near-equal frequencies of lateral and medial injuries in specimens with a shallow emargination (slit or sinus) suggest random distribution. Shell form (narrow or broad) does not exert overall control on the distribution of injuries except, perhaps, in some broad explanate shells with an insignificant medial emargination. While this suggests that it is the type of medial emargination that governs distribution of injuries in these forms, it is not clear if this is a result of passive selection due to structural geometry or preferential targeting by predators (i.e. site-specific mode of attack). Predation strategies on bellerophontiform molluscs thus seem to be dependent on the morphological features of the shells rather than their interpretation as tergomyan or gastropod.
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| 19. |
- Ekberg, Karin, et al.
(författare)
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C-Peptide replacement therapy and sensory nerve function in type 1 diabetic neuropathy
- 2007
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Ingår i: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 30:1, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE - C-peptide replacement in animals results in amelioration of diabetes-induced functional and structural abnormalities in peripheral nerves. The present study was undertaken to examine whether C-peptide administration to patients with type 1 diabetes and peripheral neuropathy improves sensory nerve function. RESEARCH DESIGN AND METHODS - This was an exploratory, double-blinded, randomized, and placebo-controlled study with three study groups that was carried out at five centers in Sweden. C-peptide was given as a replacement dose (1.5 mg/day, divided into four subcutaneous doses) or a dose three times higher (4.5 mg/day) during 6 months. Neurological examination and neurophysiological measurements were performed before and after 6 months of treatment with C-peptide or placebo. RESULTS - The age of the 139 patients who completed the protocol was 44.2 ± 0.6 (mean ± SE) years and their duration of diabetes was 30.6 ± 0.8 years. Clinical neurological impairment (NIA) (score >7 points) of the lower extremities was present in 86% of the patients at baseline. Sensory nerve conduction velocity (SCV) was 2.6 ± 0.08 SD below body height-corrected normal values at baseline and improved similarly within the two C-peptide groups (P < 0.007). The number of patients responding with a SCV peak potential improvement >1.0 m/s was greater in C-peptide-treated patients than in those receiving placebo (P < 0.03). In the least severely affected patients (SCV < 2.5 SD below normal at baseline, n = 70) SCV improved by 1.0 m/s (P < 0.014 vs. placebo). NIA score and vibration perception both improved within the C-peptide-treated groups (P < 0.011 and P < 0.002). A1C levels (7.6 ± 0.1% at baseline) decreased slightly but similarly in C-peptide- and placebo-treated patients during the study. CONCLUSIONS - C-peptide treatment for 6 months improves sensory nerve function in early-stage type 1 diabetic neuropathy.
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| 20. |
- Eriksson, Monica, 1952-, et al.
(författare)
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A sense of coherence and health. The Salutogenesis in a societal context : Åland - a special case?
- 2007
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Ingår i: Journal of Epidemiology and Community Health. - 0143-005X .- 1470-2738. ; 61:8, s. 684-688
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Tidskriftsartikel (refereegranskat)abstract
- Background:Antonovsky's salutogenic concept of a sense of coherence (SOC) has proved most influential in the way that health is now perceived.Aim:To (1) describe the distribution of SOC among 40–70-year-old Ålanders; (2) examine the distribution of depression in Åland, Finland, and its relationship with SOC; and (3) discuss the findings within a salutogenic framework in a societal context.Design:A cross-sectional study design was adopted. Antonovsky's SOC Questionnaire (13 items) and the Beck Depression Inventory (13 items) were used. In addition, in a separate questionnaire, sociodemographic information about each participant was sought, together with a question specific to this study and designed to measure self-rated health.Setting:Åland, an autonomous island province of Finland.Results:The proportion of respondents reporting good health was high (64%). The overall mean (SD) SOC was 70.7 (11.7) points, whereas for farmers and fishermen it was 73.88 (8.8) and 74.33 (9.2) points, respectively. SOC was significantly and strongly related to the self-rated health score. The higher the SOC, the better was the health of the respondents. Furthermore, the study provided clear evidence of the potential of the SOC concept as a positive mental health indicator.Conclusion:The SOC seems to be a health-promoting resource that supports the development of a positive subjective state of health.
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| 21. |
- Fetscher, B., et al.
(författare)
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Making Random Judgments: Automatically Generating Well-Typed Terms from the Definition of a Type-System
- 2015
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. ; 9032, s. 383-405
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a generic method for randomly generating well-typed expressions. It starts from a specification of a typing judgment in PLT Redex and uses a specialized solver that employs randomness to find many different valid derivations of the judgment form. Our motivation for building these random terms is to more effectively falsify conjectures as part of the tool-support for semantics models specified in Redex. Accordingly, we evaluate the generator against the other available methods for Redex, as well as the best available custom well-typed term generator. Our results show that our new generator is much more effective than generation techniques that do not explicitly take types into account and is competitive with generation techniques that do, even though they are specialized to particular type-systems and ours is not.
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| 22. |
- Fraixedas, Sara, et al.
(författare)
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Substantial decline of Northern European peatland bird populations : Consequences of drainage
- 2017
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 214, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peatland species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habitat preferences of peatland bird species, hence helping to target conservation to the most relevant habitat types. There was a general decline of 40% in Northern European peatland bird population sizes in 1981–2014 (speed of decline 1.5%/year) largely driven by Finland, where populations declined almost 50% (2.0% annual decline). In Sweden and Norway, peatland bird populations declined by 20% during 1997–2014 (1.0% annual decline). In contrast, southern populations in Estonia and Latvia, where the majority of open peatlands are protected, showed a 40% increase during 1981–2014 (1.0% annual increase). The most important habitat characteristics preferred by common peatland species in Finland were openness and low tree height, while wetness proved to be an important feature for waders. Drainage of peatlands had clear negative effects on the densities of many species, with the only exception of rustic bunting, which specializes on edge habitats. Our findings call for more effective conservation actions in Northern European peatland habitats, especially in Finland where peatland drainage represents a major threat to biodiversity.
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| 23. |
- Garmabaki, Amir, et al.
(författare)
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Software Fault Detection in Control Systems
- 2017
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Ingår i: Risk, Reliability and Safety. - : CRC Press. - 9781138029972 - 9781315374987 ; , s. 2006-2012
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Konferensbidrag (refereegranskat)abstract
- Fault detection in the software of control systems is a difficult task. In largely interconnected systems, not only the individual performance of one channel, but also its interaction with other components, must be considered. In this conceptual paper, we outline a new maintenance concept for the detection of software faults in control systems. The concept includes two approaches, morning gymnastics test and envelope analysis. The morning gymnastics test generates data for a baseline of the current operational abilities in contrast to the specified abilities and should be applied when feasible in continuous production systems. The test integrates historical and new sets of data to track degradation trends. Envelope analysis can be performed to detect operational anomalies and is based on subsequent deep analysis to distinguish software and hardware faults from each other. By using the envelope analysis it is possible to identify failures and disturbances affecting the control system. Thus, the proposed maintenance concept may facilitate detection and identification of potential failures in critical automated system.
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| 24. |
- Grünwald, Jan, et al.
(författare)
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Ecological traits predict population trends of urban birds in Europe
- 2024
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Ingår i: Ecological Indicators. - 1470-160X. ; 160
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Tidskriftsartikel (refereegranskat)abstract
- The population dynamics of urban animals has been so far remarkably understudied. At the same time, urban species’ population trends can provide important information on the consequences of environmental changes in cities. We modelled long-term population trends of 93 bird species breeding in urban areas in 16 European countries as a function of species’ traits, characterising variability in their urbanization and ecology. We found that: (i) earlier colonisers have more negative population trends than recent colonisers; (ii) more urbanized open habitat species had more positive population trends than less urbanized open habitat species; (iii) highly urbanized birds breeding above the ground had more negative trends than highly urbanized ground breeders. These patterns can be explained by several processes occurring in cities as well as outside city borders. Namely, (i) pre-industrial colonisers might struggle to persist in rapidly changing urban areas, limiting their foraging and breeding opportunities of the birds. (ii) Open habitats are under pressure of intensive agricultural exploitation in rural areas, which may negatively affect populations of less urbanized birds. In contrast, urban areas do not experience such pressure keeping the trends of urbanized open habitat species more positive. (iii) Differences in population trends between highly urbanized ground and above-ground breeders suggest that the latter may lose their breeding opportunities in modern buildings that do not provide suitable breeding sites. Our results indicate that even once successful, city dwellers may not keep pace with changes in urban areas, but these areas may also provide suitable habitats for biodiversity.
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| 25. |
- Gullberg, Ebba, 1977-
(författare)
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Objects and objectivity : Alternatives to mathematical realism
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is centered around a set of apparently conflicting intuitions that we may have about mathematics. On the one hand, we are inclined to believe that the theorems of mathematics are true. Since many of these theorems are existence assertions, it seems that if we accept them as true, we also commit ourselves to the existence of mathematical objects. On the other hand, mathematical objects are usually thought of as abstract objects that are non-spatiotemporal and causally inert. This makes it difficult to understand how we can have knowledge of them and how they can have any relevance for our mathematical theories. I begin by characterizing a realist position in the philosophy of mathematics and discussing two of the most influential arguments for that kind of view. Next, after highlighting some of the difficulties that realism faces, I look at a few alternative approaches that attempt to account for our mathematical practice without making the assumption that there exist abstract mathematical entities. More specifically, I examine the fictionalist views developed by Hartry Field, Mark Balaguer, and Stephen Yablo, respectively. A common feature of these views is that they accept that mathematics interpreted at face value is committed to the existence of abstract objects. In order to avoid this commitment, they claim that mathematics, when taken at face value, is false. I argue that the fictionalist idea of mathematics as consisting of falsehoods is counter-intuitive and that we should aim for an account that can accommodate both the intuition that mathematics is true and the intuition that the causal inertness of abstract mathematical objects makes them irrelevant to mathematical practice and mathematical knowledge. The solution that I propose is based on Rudolf Carnap's distinction between an internal and an external perspective on existence. I argue that the most reasonable interpretation of the notions of mathematical truth and existence is that they are internal to mathematics and, hence, that mathematical truth cannot be used to draw the conclusion that mathematical objects exist in an external/ontological sense.
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| 26. |
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| 27. |
- Harnesk, Dan, et al.
(författare)
-
Action research supported implementation of a crisis competence centre
- 2009
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Ingår i: ISCRAM 2009. - Göteborg. - 9789163346040
-
Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to describe the development of a regional crisis competence centre in Sweden. The overall research approach utilizes action research methodology to support the development process. The overall development process is divided into three steps; early need finding, the organizational platform, and business development. This paper is devoted to the first phase - early need finding - which deals with the specific needs and demand of four municipality organizations and how these requirements can be converged into a organizational setting that correspond to national crisis management strategies as well as regional responsibilities in crisis management. The research approach is action based and the theoretical considerations to support progress in development activities are from the Actor Network Theory (ANT). The main conclusion from the research is that the formation of a crisis competence centre revolves around sharing competences, and compromising between internal and external objectives in the progress towards a common goal.
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| 28. |
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| 29. |
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| 30. |
- Harnesk, Dan, et al.
(författare)
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Materializing organizational information security
- 2012
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Ingår i: Nordic Contributions in IS Research. - Berlin, Heidelberg : Encyclopedia of Global Archaeology/Springer Verlag. - 9783642322693 - 9783642322709 ; , s. 76-94
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Konferensbidrag (refereegranskat)abstract
- In the context of situated elderly care this paper discusses the intertwined relationship between organizational security objectives, technology, and employees' security behavior. We use findings from a single case study to aid in our understanding of how managers sought to create a secure work environment by introducing behavioral security technology, and how employees appreciated the new security software in everyday routines. Theoretically the case study is informed by sociomateriality in that it employs the notion of technological affordances of behavioral security technology. Findings show that security technology material is an integral part of security management and security in use, and that both the technical actor and human actors contributed to cultivation of the information security practice in the elderly care center
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| 31. |
- Harnesk, Dan, et al.
(författare)
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Shaping security behaviour through discipline and agility: Implications for information security management
- 2011
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Ingår i: Information Management & Computer Security. - : Emerald. - 0968-5227 .- 1758-5805. ; 19:4, s. 262-276
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to broaden the understanding about security behaviour by developing a security behavior typology based on the concepts of discipline and agility.Design/methodology/approach: A case study was designed to analyze security behaviours in one public nursing centre. The inquiry was organized around the themes discipline and agility, culture,and security processes in order to get an in-depth understanding of the complex relationship between security management, referred to as discipline, and security in use, referred to as agility.Findings: The paper shows that security behaviour can be shaped by discipline and agility and that both can exist collectively if organizations consider the constitutional and existential aspects of information security management.Practical implications: This research makes a pivotal stand for the issue how security behaviours narrate a broad picture to enhance information security management. In particular, this will improve design of information security training and awareness programs.Originality/value: This research is relevant to information security management in organizations, particularly as behavioural and cultural aspects are becoming increasingly significant for maintaining and also designing systemic information security management.
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| 32. |
- Harnesk, Dan, et al.
(författare)
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Socio-technical design approach for crisis management information systems
- 2009
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Ingår i: International Journal of Information Systems for Crisis Response and Management. - : IGI Global. - 1937-9390 .- 1937-9420. ; 1:3
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Tidskriftsartikel (refereegranskat)abstract
- This article describes research in progress of a design approach for crisis management information systems. A qualitative study was designed to gather data from four municipalities in northern Sweden, which all have responsibility for crisis management in each local environment. The purpose with the article is to discuss broad but strongly related information issues to crisis management and from that suggest a socio-technical oriented approach for crisis management information systems design. The preliminary design approach suggests that a network of knowledge, IT management and information integration is a promising base for design in the area. Considering that responsible actors in crisis environments have great knowledge in crisis planning and operation indicate that such an environment can be understood as a network of knowledge that account for both the social and technical dimension during crises. Theories from IT management and information integration provide input to the technical dimension of the suggested design approach.
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| 33. |
- Hedenström, Mattias, et al.
(författare)
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Identification of lignin and polysaccharide modifications in Populus wood by chemometric analysis of 2D NMR spectra from dissolved cell walls
- 2009
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Ingår i: Molecular Plant. - : Elsevier BV. - 1674-2052 .- 1752-9867. ; 2:5, s. 933-942
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Tidskriftsartikel (refereegranskat)abstract
- 2D (13)C-(1)H HSQC NMR spectroscopy of acetylated cell walls in solution gives a detailed fingerprint that can be used to assess the chemical composition of the complete wall without extensive degradation. We demonstrate how multivariate analysis of such spectra can be used to visualize cell wall changes between sample types as high-resolution 2D NMR loading spectra. Changes in composition and structure for both lignin and polysaccharides can subsequently be interpreted on a molecular level. The multivariate approach alleviates problems associated with peak picking of overlapping peaks, and it allows the deduction of the relative importance of each peak for sample discrimination. As a first proof of concept, we compare Populus tension wood to normal wood. All well established differences in cellulose, hemicellulose, and lignin compositions between these wood types were readily detected, confirming the reliability of the multivariate approach. In a second example, wood from transgenic Populus modified in their degree of pectin methylesterification was compared to that of wild-type trees. We show that differences in both lignin and polysaccharide composition that are difficult to detect with traditional spectral analysis and that could not be a priori predicted were revealed by the multivariate approach. 2D NMR of dissolved cell wall samples combined with multivariate analysis constitutes a novel approach in cell wall analysis and provides a new tool that will benefit cell wall research.
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| 34. |
- Heldbjerg, Henning, et al.
(författare)
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Contrasting population trends of common starlings (Sturnus vulgaris) across Europe
- 2019
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Ingår i: Ornis Fennica. - 0030-5685. ; 96:4, s. 153-168
-
Tidskriftsartikel (refereegranskat)abstract
- The greatest loss of biodiversity in the EU has occurred on agricultural land. The Common Starling (Sturnus vulgaris) is one of the many numerous and widespread European farmland breeding bird species showing major population declines linked to European agricultural intensification. Here we present results based on monitoring data collected since 1975 in 24 countries to examine the influence of changing extent of grassland and cattle abundance (based on results of earlier studies showing the importance of lowland cattle grazed grassland for the species), wintering provenance and temperature on national breeding population trends of Starlings across Europe. Positive Starling population trends in Central-East Europe contrast with negative trends in North and West Europe. Based on this indicative approach, we found some support for the importance of cattle stock and no support for grassland, temperature or wintering provenance to explain Starling population trends in Europe. However, we acknowledge such a European-wide analysis may conceal regional differences in responses and suggest that currently accessible national land use data might be insufficient to describe the detailed current changes in animal husbandry and grassland management that may be responsible for changes in food availability and hence breeding Starling abundance and their differences across Europe. Reviewing results from local studies relating Starling population trends to local agricultural change offer contradictory results, suggesting complex interacting processes at work. We recommend combining national datasets on demography, land-use/agricultural practices and from autecological research to better explain the reasons for contrasting Starling trends across Europe, to enable us to predict how changing agriculture will affect Starlings and potentially suggest mitigation measures to restore local populations where possible.
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| 35. |
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| 36. |
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Hughes, John, 1958, et al.
(författare)
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Specification-Based Testing with QuickCheck
- 2003
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Ingår i: The fun of programming - edited by Jeremy Gibbons and Oege de Moor. - 1403907722 ; , s. 17-40
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 41. |
- Johansson, Yvonne, et al.
(författare)
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Malnutrition in a home-living older population : prevalence, incidence and risk factors. A prospective study
- 2009
-
Ingår i: JOURNAL OF CLINICAL NURSING. - : Wiley. - 0962-1067 .- 1365-2702. ; 18:9, s. 1354-1364
-
Tidskriftsartikel (refereegranskat)abstract
- To prospectively investigate and describe the prevalence and incidence of malnutrition among home-living older people, related to demographic and medical factors, self-perceived health and health-related quality of life. Another aim was to find predictors for developing risk of malnutrition. Risk factors for malnutrition have previously been identified as diseases, several medications, low functional status, symptoms of depression and inadequate nutrient intake. Most studies are cross-sectionally performed at hospitals or in nursing care settings. A prospective study with a sample of 579 home-living older people, randomly selected from a local national register. Examinations were performed at baseline and yearly follow-ups two to four times. Questionnaires validated and tested for reliability, to detect risk of malnutrition (Mini Nutritional Assessment), symptoms of depression (Geriatric Depression Scale-20), cognitive function (Mini Mental State Examination), health-related quality of life (Nottingham Health Profile), well-being (Philadelphia Geriatric Center Multilevel Assessment Instrument) self-perceived health, demographic factors, anthropometry and biochemical examinations. Predictors were searched for through multiple logistic regression analysis with the MNA as dependent factor. The prevalence of risk for malnutrition was 14.5%, according to the MNA. Two risk factors for malnutrition were lower handgrip strength and lower self-perceived health. The incidence of risk for malnutrition at follow-ups was between 7.6% and 16.2%. Predictors for developing malnutrition were higher age, lower self-perceived health and more symptoms of depression. Men with symptoms of depression had a higher risk of developing malnutrition. Lower self-perceived health had the highest power to predict risk for malnutrition, with increased number of depression symptoms and higher age as second and third predictors. A regular and combined assessment using the Mini Nutrition Assessment, Geriatric Depression Scale-20 and self-perceived health as a base for identifying people in need, is one way to prevent the development of malnutrition.
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| 42. |
- Johansson, Yvonne, et al.
(författare)
-
Self-perceived health among older men living in their own residence : a four year follow-up study
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This study characterize older men, who perceived themselves as healthy, with focus on demographical, social, medical and functional factors, and describe changes within the healthy group over time and find predictors of self-perceived health. The study has a prospective design and included 303 men, 75 and 80 years old, living in a municipality in the south of Sweden. Data collection took place 2001-2006 in a total of three – five examinations at an interval of one year. The examinations included questionnaires validated and tested for reliability, assessing the nutritional status, (Mini Nutritional Assessment), symptoms of depression (Geriatric Depression Scale-20), cognitive function (Mini Mental State Examination), health-related quality of life (Nottingham Health Profile), wellbeing (Philadelphia Geriatric Centre Multilevel Assessment Instrument), demographic factors, physical- and biochemical assessments. The men were divided into two groups according to their self-perceived health, 58% (n=175) perceived themselves as healthy and 42% n=128) as less healthy. Good physical health, the ability to walk a distance outdoors, an ability to maintain a social network and having energy were factors important to feeling healthy among men at baseline. Analyses at the follow-ups included men whom still perceived themselves as healthy and men who perceived their health as being impaired. Seventy five percent (n=132) of the healthy group at baseline still perceived themselves as healthy at the first follow-up. Important factors for a self perceived good health when growing older were feeling mentally well and being able to walk up and downstairs. These results indicated that areas representing the individuals own perception and ability are important to feel healthy.
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| 43. |
- Karlsson, Lennart, et al.
(författare)
-
Functional Products - Goodbye to the industrial age
- 2012
-
Ingår i: Ericsson Business Review. - Stockholm, Sweden : Telefonaktiebolaget LM Ericsson. - 1653-9486. ; 18:2, s. 21-24
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 44. |
- Kvarnström, Lasse, et al.
(författare)
-
Historia i Linköping
- 1999
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Forskningsinriktningen vid den historiska avdelningen vid Linköpings universitet har sedan länge en stark socialhistorisk profil. kollektivens vardag studeras på en rad områden, på olika nivåer och över sinsemellan skilda tidsperioder. Det gäller inom såväl agrara som industriella miljöer, på samhällelig liksom på grupp-, familje- och individnivå samt över tid som omspänner senantiken till det sena 1900-talets historia. Hur identiteter skapas, tillägnas och förändras är en alltmer växande inriktning, liksom anknytningen till socialpolitiska ideer, normsystem, attityder, värderingar och mentaliteter. Även den rättshistoriska och ekonomiskhistoriska forskningen ryms inom detta fält. Den historiska demografin utgör också traditionellt en stark del av det socialhistoriska fältet. Studier av arbeta och ohälsa, sjuklighet, dödlighet och hälsopolitik ligger långt framme. Bredden i den socialhistoriska profilen morsvaras av en mångfald melodologiska inslag.Skriftserien Socialhistoria i Linköping uppmärksammar denna profil och vilka uttryck den tar sig i grundutbildningen. I serien publiceras i första hand uppsatser skrivna på C- och D- nivå, men även bidrag från lärare och doktorander vid avdelningen förekommer.Detta nummer av Socialhistoria i Linköping är en specialutgåva till Svenska historikermötet i Linköping 23-25 april 1999
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| 45. |
- Kyösti, Petter, et al.
(författare)
-
Process-SME Project : Exceeded Expectations
- 2019
-
Rapport (populärvet., debatt m.m.)abstract
- This publication ‘Process-SME Project – Exceeded Expectations’ introduces a Nordic project Process-SME, which main objective is to improve the competitiveness of SMEs whose customers are found within the process, mining, energy, oil, and gas industries. The project supports these SMEs by identifying their needs and potential opportunities, developing new business models, building European partnerships and applying for EU-level funding for project proposals on SMEs’ business behalf. Furthermore, the Process-SME project aims to develop SMEs’ products, services and other offerings.
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| 46. |
- Kyösti, Petter, et al.
(författare)
-
SOA-Based Platform Use in Development and Operation of Automation Solutions: Challenges, Opportunities, and Supporting Pillars towards Emerging Trends
- 2022
-
Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- The paper which is based on a literature review combined with a case study, spanning manufacturing and process industry contexts, set out to determine whether there is an emerging trend to use a service-oriented architecture (SOA)-based platform supporting microservices while developing and operating automation solutions while also considering effects and implications. The results point out that there is a significant potential, during the lifecycle, to save significant engineering time/effort during the development-related and operations phases while integrating systems and adding new types of sensors or other equipment. In addition, the results indicate that there are also business development advantages when promoting an SOA-based architecture supporting microservices towards monolith architectures and that a cybersecurity baseline can be included as part of the platform baseline. However, there is a threshold, before the benefits can be reaped, in terms of the need to build up a competency and skills set concerning the platform, SOA and microservices, as many providers of automation solutions are still doing the development in a traditional old monolithic style with hard-coded integrations between components and systems. Finally, we see an emerging trend to use a competent SOA-based platform in the development and operation of automation solutions.
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| 47. |
- Källström, Elisabeth, et al.
(författare)
-
Analysis of Automatic Transmission Vibration for Clutch Slippage Detection
- 2015
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Ingår i: 22nd International Congress on Sound and Vibration 2015 (ICSV 22). - : Curran Associates, Inc.. - 9781510809031
-
Konferensbidrag (refereegranskat)abstract
- Heavy duty construction equipment is generally equipped with automatic transmission enablingto change gear ratio automatically. The clutches in an automatic transmission transfer torquefrom the engine to the gearbox and clutch failures may result in costly downtime of constructionequipment. To prevent costly downtime of construction equipment, condition monitoring in com-bination with condition based maintenance may be utilized. Different sensor data are collectedon a machine that enables condition monitoring. Vibration have been measured on an automatictransmission in a construction equipment machine during controlled driving sessions, with andwithout clutch slippage, on a test track. An initial investigation of the vibration measured on theautomatic transmission have been carried out with the purpose to find out if the vibration maycontain reliable information related to clutch slippage considered to be abnormal. Initial signalanalysis of the data have been carried out using Spectrogram and Spectral Kurtosis methods. Theresults indicate that information related to abnormal clutch slippage may be extracted from vibra-tion measured on an automatic transmission in a construction equipment machine.
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| 48. |
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| 49. |
- Källström, Elisabeth
(författare)
-
Data Driven Condition Monitoring for Transmission and Axles
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As the requirements to improve up-time and thus to reduce costly down-time con-tinuously increases, the construction equipment business focuses on more and newways to increase ability and sensitivity of early fault detection of critical compo-nents and parts in order to prevent failure. Failure of critical components in theheavy duty machine may lead to unnecessary stops and expensive downtime. Withmore features added to the heavy duty construction equipment, its complexity in-creases and early fault detection of certain components becomes more challengingdue to too many fault codes generated when a failure occurs. Hence, the need tocomplement the present onboard diagnostic methods with more sophisticated diag-nostic methods for adequate condition monitoring of the heavy duty constructionequipment in order to improve uptime. Further, reduced downtime leads to im-proved customer satisfaction, reduced warranty and service cost. In addition, thisupgrade result in the construction equipment business staying competitive with im-provement in sales and profit.Heavy duty construction equipment is often equipped with a driveline whichconsists of major components, such as torque converter, gearbox, clutches, bearingsand axles. The driveline enables the transferring of torque from the engine to thegearbox, with the clutches enabling automatic gear ratio changes, and this drivingtorque from the gearbox is further transmitted to the wheels via the axles. Thesemajor components of a driveline may be considered as crucial components whosefailure may result in costly downtime. Since the current on-board diagnostic sys-tems use simple rules and maps to carry out diagnosis, most failures are not easy todiagnose as a result of too many fault codes being generated when there is a fail-ure. This means that, the engineers and technicians may have to spend substantialamount of time to identify the failure and root-cause. As a result, where major driv-eline parts are involved, this may cause the machine to stand still until the problemis identified and repaired, with a negative impact on customer satisfaction.In this thesis, condition monitoring methods are presented with the purpose toprovide a diagnostic framework possible to implement onboard for monitoring ofcritical driveline parts in order to improve uptime.In this thesis the gap in condition monitoring of major driveline components in an actual machine is addressed. A methodology for monitoring the health of theautomatic transmission and axles onboard the machine using vibration signals andavailable CAN-bus signals has been developed. Furthermore, this thesis presentsa vibration based diagnostic framework for the monitoring of the torque converter,gearbox, bearings and axles. For the development of this diagnostic framework,sensor data from the gearbox, torque converter, bearings and axles are considered.Further, the feature extraction of the data collected has been carried out using or-der analysis technique and adequate signal processing methods, which includes,Adaptive Line Enhancer, Order Power Spectrum and Order Modulation Spectrumrespectively. In addition, Bayesian learning was utilized for learning of the extractedfeatures onboard. The results indicate that the vibration properties of the gearbox,torque converter, bearings and axle are relevant for early fault detection of the driv-eline. Furthermore, vibration provides information about the internal features ofthese components for detecting deviations from normal behavior.A different approach was utilized for the monitoring of the automatic transmis-sion clutches. The feature extraction methods utilized for the monitoring of theautomatic transmission clutches are based on moving average square value filter-ing and a measure of the fourth order statistical properties of the CAN-bus signals.Results show that the feature extraction methods provide an indication of clutchslippage deviations. This thesis also includes an investigation of clutch slippage de-tection from driveline vibrations based on spectrogram and spectral Kurtosis meth-ods.In this way, the developed methods may be implemented onboard for the con-tinuous monitoring of these critical driveline parts of the heavy duty constructionequipment so that if their health starts to degrade a service and/or repair may bescheduled well in advance of a potential axle failure and in that way the downtimeof a machine may be reduced and costly replacements and repairs avoided.
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| 50. |
- Källström, Elisabeth, et al.
(författare)
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Identification of vibration properties of heavy duty machine driveline parts as a base for adequate condition monitoring: Axle
- 2016
-
Ingår i: ICSV 2016 - 23rd International Congress on Sound and Vibration. - : INT INST ACOUSTICS & VIBRATION. - 9789609922623
-
Konferensbidrag (refereegranskat)abstract
- With increasing complexities in the heavy duty construction equipment, early fault detection of certain components in the machine becomes more and more challenging due to too many fault code generated when a failure occurs. The axle is one of such component. The axle transfers driving torque from the transmission to the wheels and axle failure may result in costly downtime of construction equipment. To reduce service cost and to improve uptime, adequate condition monitoring based on sensor data from the axle is considered. Vibration is measured on the axle. Analysis of the data has been carried out using adequate signal processing methods. The results indicate that the vibration properties of the axle are relevant for early fault detection of the axle. In this way; the health of the axle may be continuously monitored on-board using the vibration information and if the axle health starts to degrade a service and/or repair may be scheduled well in advance of a potential axle failure and in that way the downtime of a machine may be reduced.
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