| 1. |
- Cesta, Carolyn E., et al.
(författare)
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Maternal polycystic ovary syndrome and risk of neuropsychiatric disorders in offspring : prenatal androgen exposure or genetic confounding?
- 2020
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 50:4, s. 616-624
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Maternal polycystic ovary syndrome (PCOS) has been proposed as a model for investigating the role of prenatal androgen exposure in the development of neuropsychiatric disorders. However, women with PCOS are at higher risk of developing psychiatric conditions and previous studies are likely confounded by genetic influences.METHODS: A Swedish nationwide register-based cohort study was conducted to disentangle the influence of prenatal androgen exposure from familial confounding in the association between maternal PCOS and offspring attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders (ASD), and Tourette's disorder and chronic tic disorders (TD/CTD). PCOS-exposed offspring (n = 21 280) were compared with unrelated PCOS-unexposed offspring (n = 200 816) and PCOS-unexposed cousins (n = 17 295). Associations were estimated with stratified Cox regression models.RESULTS: PCOS-exposed offspring had increased risk of being diagnosed with ADHD, ASD, and TD/CTD compared with unrelated PCOS-unexposed offspring. Associations were stronger in girls for ADHD and ASD but not TD/CTD [ADHD: adjusted hazard ratio (aHR) = 1.61 (95% confidence interval (CI) 1.31-1.99), ASD: aHR = 2.02 (95% CI 1.45-2.82)] than boys [ADHD: aHR = 1.37 (95% CI 1.19-1.57), ASD: aHR = 1.46 (95% CI 1.21-1.76)]. For ADHD and ASD, aHRs for girls were stronger when compared with PCOS-unexposed cousins, but slightly attenuated for boys.CONCLUSIONS: Estimates were similar when accounting for familial confounding (i.e. genetics and environmental factors shared by cousins) and stronger in girls for ADHD and ASD, potentially indicating a differential influence of prenatal androgen exposure v. genetic factors. These results strengthen evidence for a potential causal influence of prenatal androgen exposure on the development of male-predominant neuropsychiatric disorders in female offspring of women with PCOS.
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| 2. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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A calculation model for ergonomics cost-benefit analyses in early product development stages
- 2012
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Ingår i: AHFE 2012: Applied Human Factors and Ergonomics Conference, San Fransisco, California, USA, 21-25 July, 2012. - : CRC Press. - 9781439870396 ; :Conference program, session 185, s. pp. 71-
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Konferensbidrag (refereegranskat)abstract
- Increasing international competition between companies has put high focus on cost-cutting actions at all levels in companies and organizations. In product development there are many design requirements to meet and often tough project budgets to keep. Requirements that are considered not profitable will often be neglected, which often affects assembly ergonomics. The objective of this study is to demonstrate the relationship between ergonomics, assembly related quality errors and associated costs and develop a cost-beneficial assessment model. The results showed that ergonomics high risk issues had 5-8 times as many quality errors as low risk issues and the earlier risk issues were found the less were the action costs. A model for cost-benefit analyses was developed based on the obtained quality data.
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| 3. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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A calculation model for ergonomics cost-benefit analyses in early product development stages
- 2012
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Ingår i: Advances in ergonomics in manufacturing. - : CRC Press. - 9781439870402 ; , s. 399-408
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Increasing international competition between companies has put high focus on cost-cutting actions at all levels in companies and organizations. In product development there are many design requirements to meet and often tough project budgets to keep. Requirements that are considered not profitable will often be neglected, which often affects assembly ergonomics. The objective of this study is to demonstrate the relationship between ergonomics, assembly related quality errors and associated costs and develop a cost-beneficial assessment model. The results showed that ergonomics high risk issues had 5-8 times as many quality errors as low risk issues and the earlier risk issues were found the less were the action costs. A model for cost-benefit analyses was developed based on the obtained quality data.
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| 4. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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A comparison of two methods for assembly complexity- What are they good for?
- 2015
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Ingår i: NES, Nordic Ergonomics society, 47th Annual Conference, 02-04 November 2015, Lillehammer, Norway. ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- This study aimed at comparing two methods for assessing manual assembly complexity, the CXB considering basic assembly complexity from product design perspective and the CXI, which assesses complexity as perceived by operators in production. The objective was to see if and how the two methods overlap. The results showed that they had some assessment criteria in common but that other criteria differed and covered different areas of interest. Both method approaches are important for a manufacturer to manage in order to create sustainable assembly conditions, good working conditions and reduce errors in manual assembly.
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| 5. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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A model for calculation of the costs of poor assembly ergonomics
- 2014
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 44:2014, s. 140-147
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Tidskriftsartikel (refereegranskat)abstract
- In product development there are many design requirements to meet and often tough project budgets to keep. Requirements that are considered not profitable will often be neglected, which affects assembly ergonomics. The objective of this study was to develop a calculation model for application in practice that enables calculation of costs of poor assembly quality related to assembly ergonomic conditions. The model is meant to be used by engineers and stakeholders in the design or redesign of manual assembly solutions. For that purpose, manual assembly tasks of 47061 cars at high, moderate and low physical load levels were analyzed with respect to assembly-related quality errors and corresponding action costs during production and on the market. The results showed that ergonomics high risk issues had 5-8 times as many quality errors as low risk issues and the earlier these were found the less were the action costs. The action costs for errors that were discovered late in assembly were 9.2 times more costly compared to early repair of errors in the factory. The action costs for quality errors that were found and corrected on the market were further 12.2 times more expensive to correct compared to actions taken in the factory. Examples are shown of how to apply the calculation model that was developed based on the obtained quality data. Relevance to industry: Both ergonomics and quality issues can be proactively solved through simultaneous risk assessment in early product development and hereby late reactive action costs can be greatly reduced.
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| 6. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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Acquisition of new knowledge in Swedish manufacturing companies - How could it be improved?
- 2017
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Ingår i: In Proceedings of Nordic Ergonomics Society (NES) conference, Lund 2017.
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Konferensbidrag (refereegranskat)abstract
- Experience has shown that new research does not reach out to companies and organizations in Sweden as desired. The spread and application of useful research results was found to be limited to relatively few companies. The situation is similar across the EU according to investigations. This means that many improvement possibilities are missed and probably also increased profitability and competitiveness. In order to explore the underlying reasons for this nineteen Swedish companies were asked about participation in an interview study. Nine agreed to participate and interviews among upper level management were accomplished in order to investigate how new knowledge was acquired and implemented. The interview study included 18 semi-open questions about: organizational relationships; decision levels; distribution of responsibility; cooperation between different departments; successful implementation factors; responsibility for ergonomics issues; management of assembly-related errors and conditions for effective knowledge dissemination. The results showed that the small businesses lacked sufficient resources to manage major changes and that binding subcontractor agreements counteracted possible improvements of product design and assembly solutions. In some cases additional implementation support is probably needed to succeed because time-consuming change initiatives that were not highly prioritized could often not be sufficiently considered. A critical mass of knowledgeable people was considered crucial to manage implementation of new methods and working procedures. It was perceived difficult to find research reports of interest for the own business. Only one company had an ergonomics specialist involved in early development phases but this expertize was wanted by several companies. Eight of nine companies thought it would be useful to increase cooperation with universities and/or research teams. There are different decision-making forums in different companies that decide on changes or implementation of new approaches and methods. Academic knowledge dissemination, implementation and need of (external) support therefore must be adapted to varying conditions in companies in order to be utilized to a much larger extent. Direct communication and local abutment is crucial. Improvement proposals were developed for how to support dissemination and implementation of new knowledge. These were:1.Compilation of easy to read summaries (including contact persons) distributed by research institutes and others conducting research, which companies could subscribe to (see 5. below).2.Innovation/competence centers (knowledge transfer offices) for collaboration/networks between SMEs, universities and research centers of various kind; financing and consulting services for exploitation of research results including specialist staff to help identify and manage relevant knowledge with business potential. 3.Additional time and budget at the end of research programs intended for further dissemination of results and implementation assistance.4.Targeted seminars and work-shops.5.A web portal including useful information of latest research publications, upcoming work-shops, projects and others of interest.6.E-learning for introduction and training in new working methods, tools and others of importance for knowledge transfer before implementation.For all proposals a clear responsibility should be agreed and decided.
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| 7. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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Assembly failures and action cost in relation to complexity level and assembly ergonomics in manual assembly (part 2)
- 2014
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 44:2014, s. 455-459
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Tidskriftsartikel (refereegranskat)abstract
- Earlier studies have demonstrated strong relationships between manual assembly at high physical loadlevels and increased amounts of quality defects compared to assembly at low physical load levels. Arecent Swedish interview study of engineers in design and manufacturing engineering indicated thatassembly complexity factors are of additional importance for the assembly quality. The objective of thisstudy was therefore to examine the significance of high and low complexity criteria and the relationshipsbetween assembly ergonomics and assembly complexity and quality failures by analyzing manual assemblytasks in car manufacturing. In total, 47 000 cars were analyzed and the results showed severalsignificant correlations between assembly ergonomics and assembly complexity, assembly time, failuresand action costs. The action costs for high complexity tasks were 22.4 times increased per task per carcompared to low complexity tasks.Relevance to industry: Assembly ergonomics and assembly complexity factors interact. Both should beproactively considered in order to keep assembly-related failures and action costs as low as possible.
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| 8. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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Assessment of manual assembly complexity: a theoretical and empirical comparison of two methods
- 2017
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 55:24, s. 7237-7250
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Tidskriftsartikel (refereegranskat)abstract
- There are several theoretical methods for assessment of assembly complexity but there are few practically applicable methods. One of the methods, CompleXity Index (CXI), aims at assessing operators´ perception of manual assembly complexity in running production. Another recently developed method, Basic Assembly Complexity (CXB) is intended for predictive assessment of basic manual assembly complexity in early product and production development. Both CXI and CXB aim to improve assembly conditions for operators, reduce assembly-related errors and the costs for corrective measures as well as increase assembly quality although in different ways and at different organizational levels and life cycle stages. The purpose of this study was to compare the two methods to obtain feedback and learn from operators experience in order to develop better predictive assessment criteria. The method comparison showed that about 50% of the CXB assessment approaches were similar to CXI but other covered different aspects. In comparison of the complexity values of the methods no significant results were obtained. However, some CXI issues that were not taken into account in CXB should be considered. CXB and CXI could be used in conjunction but further assessment criteria are probably needed.
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| 9. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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Basic complexity criteria and their impact on manual assembly quality in actual production
- 2017
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 58, s. 117-128
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Tidskriftsartikel (refereegranskat)abstract
- Increasing design and assembly complexity are challenges facing the automotive industry today because increasing number of car variants and build options can result in immense difficulties and lead to costly assembly errors and quality losses. In order to remain on the market these conditions must nevertheless be managed by companies in hard competition with other manufacturers. The objective of this study was to analyze the impact of newly developed basic complexity criteria (CXB) on assembly quality and associated costs for corrective measures in manual assembly of cars. Data on error rate and action costs of assembly tasks of different complexity level was collected and analyzed. The inter-relationship between different complexity criteria was analyzed to see whether any criteria had a greater impact than others. The results showed that the action costs/car increased with increasing complexity level and that several complexity criteria together resulted in increased action costs. Some criteria tended to have a greater impact than others but need more research. The results further suggest that if high complexity issues are identified and replaced by low complexity solutions the assembly related action costs in manual assembly are likely to decrease.Relevance to Industry: By reduction of basic assembly complexity already in early planning stages in product development significant reduction of costly assembly related action costs in manual assembly can probably be made.
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| 10. |
- Falck, Ann-Christine, 1949, et al.
(författare)
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Criteria for assessment of basic assembly complexity
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 44, s. 424-428
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Konferensbidrag (refereegranskat)abstract
- Tough competition force companies to develop and increase their product assortment in order to maintain their market share. This has resulted in numerous product variants with more features and build options. The complexity and risk of quality errors will increase. Managing complex product and installation conditions will result in distinct competitive advantages. Research has shown that sustainable and more cost-efficient assembly solutions can be obtained by proactive improvement of the working environment and installation conditions for the operators. Significant reduction of costly corrective measures can be made. The objective of this paper was to demonstrate criteria for proactive assessment of manual assembly complexity, which have been developed and verified in several studies. A further objective was to clarify and quantify included criteria as far as possible to enable a more general application in manual mass production of complex products.
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