| 1. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Multi-objective optimization of material model parameters of an adhesive layer by using SPEA2
- 2015
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Ingår i: Advances in structural and multidisciplinary optimization. - : The International Society for Structural and Multidisciplinary Optimization (ISSMO). - 9780646943947 ; , s. 249-254
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Konferensbidrag (refereegranskat)abstract
- The usage of multi material structures in industry, especially in the automotive industry are increasing. To overcome the difficulties in joining these structures, adhesives have several benefits over traditional joining methods. Therefore, accurate simulations of the entire process of fracture including the adhesive layer is crucial. In this paper, material parameters of a previously developed meso mechanical finite element (FE) model of a thin adhesive layer are optimized using the Strength Pareto Evolutionary Algorithm (SPEA2). Objective functions are defined as the error between experimental data and simulation data. The experimental data is provided by previously performed experiments where an adhesive layer was loaded in monotonically increasing peel and shear. Two objective functions are dependent on 9 model parameters (decision variables) in total and are evaluated by running two FEsimulations, one is loading the adhesive layer in peel and the other in shear. The original study converted the two objective functions into one function that resulted in one optimal solution. In this study, however, a Pareto frontis obtained by employing the SPEA2 algorithm. Thus, more insight into the material model, objective functions, optimal solutions and decision space is acquired using the Pareto front. We compare the results and show good agreement with the experimental data.
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| 2. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Radial basis functions as surrogate models with a priori bias in comparison with a posteriori bias
- 2017
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Ingår i: Structural and multidisciplinary optimization (Print). - : Springer Science and Business Media LLC. - 1615-147X .- 1615-1488. ; 55:4, s. 1453-1469
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Tidskriftsartikel (refereegranskat)abstract
- In order to obtain a robust performance, the established approach when using radial basis function networks (RBF) as metamodels is to add a posteriori bias which is defined by extra orthogonality constraints. We mean that this is not needed, instead the bias can simply be set a priori by using the normal equation, i.e. the bias becomes the corresponding regression model. In this paper we demonstrate that the performance of our suggested approach with a priori bias is in general as good as, or even for many test examples better than, the performance of RBF with a posteriori bias. Using our approach, it is clear that the global response is modelled with the bias and that the details are captured with radial basis functions. The accuracy of the two approaches are investigated by using multiple test functions with different degrees of dimensionality. Furthermore, several modeling criteria, such as the type of radial basis functions used in the RBFs, dimension of the test functions, sampling techniques and size of samples, are considered to study their affect on the performance of the approaches. The power of RBF with a priori bias for surrogate based design optimization is also demonstrated by solving an established engineering benchmark of a welded beam and another benchmark for different sampling sets generated by successive screening, random, Latin hypercube and Hammersley sampling, respectively. The results obtained by evaluation of the performance metrics, the modeling criteria and the presented optimal solutions, demonstrate promising potentials of our RBF with a priori bias, in addition to the simplicity and straight-forward use of the approach.
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| 3. |
- Andreasson, Rebecca, et al.
(författare)
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Effects of Visualizing Missing Data : An Empirical Evaluation
- 2014
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Ingår i: 18th International Conference on Information Visualisation (IV). - : IEEE conference proceedings. - 9781479941032 ; , s. 132-138
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Konferensbidrag (refereegranskat)abstract
- This paper presents an empirical study that evaluates the effects of visualizing missing data on decision-making tasks. A comparison between three visualization techniques: (1) emptiness, (2) fuzziness, and (3) emptiness plus explanation, revealed that the latter technique induced significantly higher degree of decision-confidence than the visualization technique fuzziness. Moreover, emptiness plus explanation yield the highest number of risky choices of the three. This result suggests that uncertainty visualization techniques affect the decision-maker and the decisionconfidence. Additionally, the results indicate a possible relation between the degree of decision-confidence and the decision-maker's displayed risk behavior.
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| 4. |
- Browall, Maria, et al.
(författare)
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Information needs of women with recently diagnosed ovarian cancer - A longitudinal study
- 2004
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Ingår i: European Journal of Oncology Nursing. - : Elsevier. - 1462-3889 .- 1532-2122. ; 8:3, s. 200-207
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the information needs among patients with ovarian cancer and whether these information needs change over time. The information needs were evaluated three times, through structured interviews, and were based on the paired comparison approach developed by Degner and colleagues. A consecutive sample of patients (n=82) with recently diagnosed ovarian cancer was asked to participate.Sixty-four patients (78%) chose to participate. The three different measurements of participants' information needs revealed only small changes in these needs. The three most important information needs, in all measurements, were information about the likelihood of cure, information about the stage and spreading of the disease, and information about different treatment options. Information regarding sexual attractiveness was the lowest ranked item in all measurements. Regarding subgroups (age, education) the only significant difference throughout all measurements was that younger patients rated issues of sexual attractiveness higher than older patients (p=0.005).In this longitudinal study patients with ovarian cancer ranked information about the disease and its treatment (i.e. likelihood of cure, stage of disease, and treatment options) highest, and information about psychosocial aspects and self-care lowest. These findings are in accordance with the results from studies of women diagnosed with other types of cancer, which used the same methodology. © 2004 Elsevier Ltd. All rights reserved.
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| 5. |
- Browall, Maria, et al.
(författare)
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The course of health related quality of life in postmenopausal women with breast cancer from breast surgery and up to five years post-treatment
- 2013
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Ingår i: Breast. - : Elsevier. - 0960-9776 .- 1532-3080. ; 49, s. S344-S345
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous studies include too few patients over 70 years to be able to assess treatment effects on Health Related Quality Of Life (HRQOL) in the older age group. We aimed to follow HRQOL in postmenopausal women (55-80 years) with breast cancer receiving adjuvant treatment, until five years post-treatment, and compare with a general population.Patients and methods: The patient sample included 150 women (adjuvant CT n=75 and RT n=75) and two reference samples from the Swedish SF-36 norm database.Results: Data from baseline showed significantly higher levels of physical functioning and general health among the patients compared to the reference sample, and significantly lower levels of bodily pain, emotional role functioning and mental health. Longitudinal analyses showed significant changes in all scales, and three different patterns (a decrease-stable, a decrease-increase, and a stable- increase pattern) were identified.Conclusion: Postmenopausal women seem to successfully manage the effects of adjuvant treatment on HRQOL.
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| 6. |
- Fathi, Masood, et al.
(författare)
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Assembly line balancing problem : a comparative evaluation of heuristics and a computational assessment of objectives
- 2018
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Ingår i: Journal of Modelling in Management. - : Emerald Group Publishing Limited. - 1746-5664 .- 1746-5672. ; 13:2, s. 455-474
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this study is to firstly investigate the efficiency of the most commonly used performance measures for minimizing the Number of Workstations (NWs) in approaches addressing Simple Assembly Line Balancing Problem (SALBP) for both straight and U-shaped line. Secondly, this study aims to provide a comparative evaluation of 20 constructive heuristics to find solutions to the SALBP-1.Design/methodology/approach – 200 problems are solved by 20 different constructive heuristics for both straight and U-shaped assembly line. Moreover, several comparisons have been made to evaluate the performance of constructive heuristics.Findings – Minimizing the Smoothness Index (SI) is not necessarily equivalent to minimizing the NWs, therefore, it should not be used as the fitness function in approaches addressing the SALBP-1. Line efficiency (LE) and the idle time (IT) are indeed reliable performance measures for minimizing the NWs. The most promising heuristics for straight and U-shaped line configurations for SALBP-1 are also ranked and introduced.Practical implications – Results are expected to help scholars and industrial practitioners to better design effective solution methods for having a most balance assembly line. This study will further help with choosing the most proper heuristic with regard to the problem specifications and line configuration.Originality/value – There is limited research assessing the efficiency of the common objectives for SALBP-1. This study is among the first to prove that minimizing the workload smoothness is not equivalent to minimizing the NWs in SALBP-1 studies. This work is also one of the first attempts for evaluating the constructive heuristics for both straight and U-shaped line configurations.
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| 7. |
- Feo, Rebecca, et al.
(författare)
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Towards a standardised definition for fundamental care : a modified Delphi study
- 2018
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Ingår i: Journal of Clinical Nursing. - : John Wiley & Sons. - 0962-1067 .- 1365-2702. ; 27:11-12, s. 2285-2299
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To generate a standardised definition for fundamental care and identify the discrete elements that constitute such care.BACKGROUND: There is poor conceptual clarity surrounding fundamental care. The Fundamentals of Care Framework aims to overcome this problem by outlining three core dimensions underpinning such care. Implementing the Framework requires a standardised definition for fundamental care that reflects the Framework's conceptual understanding, as well as agreement on the elements that comprise such care (i.e., patient needs, such as nutrition, and nurse actions, such as empathy). This study sought to achieve this consensus.DESIGN: Modified Delphi study.METHODS: Three phases: (1) engaging stakeholders via an interactive workshop; (2) using workshop findings to develop a preliminary definition for, and identify the discrete elements that constitute, fundamental care; and (3) gaining consensus on the definition and elements via a two-round Delphi approach (Round 1 n=38; Round 2 n=28).RESULTS: Delphi participants perceived both the definition and elements generated from the workshop as comprehensive, but beyond the scope of fundamental care. Participants questioned whether the definition should focus on patient needs and nurse actions, or more broadly on how fundamental care should be delivered (e.g., through a trusting nurse-patient relationship), and the outcomes of this care delivery. There were also mixed opinions whether the definition should be nursing specific.CONCLUSIONS: This study has initiated crucial dialogue around how fundamental care is conceptualised and defined. Future work should focus on further refinements of the definition and elements with a larger, international group of practising nurses and service users. This article is protected by copyright. All rights reserved.
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| 8. |
- Ferrie, Jane E., et al.
(författare)
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Job insecurity and risk of diabetes : a meta-analysis of individual participant data
- 2016
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Ingår i: CMJA. Canadian Medical Association Journal. Onlineutg. Med tittel. - : Canadian Medical Association,Association Medicale Canadienne. - 0820-3946 .- 1488-2329. ; 188:17-18, s. E447-E455
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Job insecurity has been associated with certain health outcomes. We examined the role of job insecurity as a risk factor for incident diabetes.METHODS: We used individual participant data from 8 cohort studies identified in 2 open-access data archives and 11 cohort studies participating in the Individual-Participant-Data Meta-analysis in Working Populations Consortium. We calculated study-specific estimates of the association between job insecurity reported at baseline and incident diabetes over the follow-up period. We pooled the estimates in a meta-analysis to produce a summary risk estimate.RESULTS: The 19 studies involved 140 825 participants from Australia, Europe and the United States, with a mean follow-up of 9.4 years and 3954 incident cases of diabetes. In the preliminary analysis adjusted for age and sex, high job insecurity was associated with an increased risk of incident diabetes compared with low job insecurity (adjusted odds ratio [OR] 1.19, 95% confidence interval [CI] 1.09-1.30). In the multivariable-adjusted analysis restricted to 15 studies with baseline data for all covariates (age, sex, socioeconomic status, obesity, physical activity, alcohol and smoking), the association was slightly attenuated (adjusted OR 1.12, 95% CI 1.01-1.24). Heterogeneity between the studies was low to moderate (age- and sex-adjusted model: I(2) = 24%, p = 0.2; multivariable-adjusted model: I(2) = 27%, p = 0.2). In the multivariable-adjusted analysis restricted to high-quality studies, in which the diabetes diagnosis was ascertained from electronic medical records or clinical examination, the association was similar to that in the main analysis (adjusted OR 1.19, 95% CI 1.04-1.35).INTERPRETATION: Our findings suggest that self-reported job insecurity is associated with a modest increased risk of incident diabetes. Health care personnel should be aware of this association among workers reporting job insecurity.
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| 9. |
- Kivimäki, Mika, et al.
(författare)
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Body mass index and risk of dementia : Analysis of individual-level data from 1.3 million individuals
- 2018
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Ingår i: Alzheimer's & Dementia. - : Elsevier. - 1552-5260 .- 1552-5279. ; 14:5, s. 601-609
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Higher midlife body mass index (BMI) is suggested to increase the risk of dementia, but weight loss during the preclinical dementia phase may mask such effects. Methods: We examined this hypothesis in 1,349,857 dementia-free participants from 39 cohort studies. BMI was assessed at baseline. Dementia was ascertained at follow-up using linkage to electronic health records (N = 6894). We assumed BMI is little affected by preclinical dementia when assessed decades before dementia onset and much affected when assessed nearer diagnosis. Results: Hazard ratios per 5-kg/m(2) increase in BMI for dementia were 0.71 (95% confidence interval = 0.66-0.77), 0.94 (0.89-0.99), and 1.16 (1.05-1.27) when BMI was assessed 10 years, 10-20 years, and >20 years before dementia diagnosis. Conclusions: The association between BMI and dementia is likely to be attributable to two different processes: a harmful effect of higher BMI, which is observable in long follow-up, and a reverse-causation effect that makes a higher BMI to appear protective when the follow-up is short. (C) 2017 The Authors. Published by Elsevier Inc. on behalf of the Alzheimer's Association.
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| 10. |
- Kivimäki, Mika, et al.
(författare)
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Long working hours and risk of coronary heart disease and stroke : a systematic review and meta-analysis of published and unpublished data for 603 838 individuals
- 2015
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Ingår i: The Lancet. - : The Lancet Publishing Group. - 0140-6736 .- 1474-547X. ; 386:10005, s. 1739-1746
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Tidskriftsartikel (refereegranskat)abstract
- Background Long working hours might increase the risk of cardiovascular disease, but prospective evidence is scarce, imprecise, and mostly limited to coronary heart disease. We aimed to assess long working hours as a risk factor for incident coronary heart disease and stroke. Methods We identified published studies through a systematic review of PubMed and Embase from inception to Aug 20, 2014. We obtained unpublished data for 20 cohort studies from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium and open-access data archives. We used cumulative random-effects meta-analysis to combine effect estimates from published and unpublished data. Findings We included 25 studies from 24 cohorts in Europe, the USA, and Australia. The meta-analysis of coronary heart disease comprised data for 603 838 men and women who were free from coronary heart disease at baseline; the meta-analysis of stroke comprised data for 528 908 men and women who were free from stroke at baseline. Follow-up for coronary heart disease was 5.1 million person-years (mean 8.5 years), in which 4768 events were recorded, and for stroke was 3.8 million person-years (mean 7.2 years), in which 1722 events were recorded. In cumulative meta-analysis adjusted for age, sex, and socioeconomic status, compared with standard hours (35-40 h per week), working long hours (>= 55 h per week) was associated with an increase in risk of incident coronary heart disease (relative risk [RR] 1.13, 95% CI 1.02-1.26; p=0.02) and incident stroke (1.33, 1.11-1.61; p=0.002). The excess risk of stroke remained unchanged in analyses that addressed reverse causation, multivariable adjustments for other risk factors, and different methods of stroke ascertainment (range of RR estimates 1.30-1.42). We recorded a dose-response association for stroke, with RR estimates of 1.10 (95% CI 0.94-1.28; p=0.24) for 41-48 working hours, 1.27 (1.03-1.56; p=0.03) for 49-54 working hours, and 1.33 (1.11-1.61; p=0.002) for 55 working hours or more per week compared with standard working hours (p(trend)<0.0001). Interpretation Employees who work long hours have a higher risk of stroke than those working standard hours; the association with coronary heart disease is weaker. These findings suggest that more attention should be paid to the management of vascular risk factors in individuals who work long hours.
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