| 1. |
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| 2. |
- Berlin, Cecilia, 1981, et al.
(författare)
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National Standard vs. Corporate-Internal Ergonomics Evaluation - an Industrial Case Study
- 2008
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Ingår i: The 40th annual Nordic Ergonomic Society Conference, NES 2008, Reykjavík, Iceland, August 11-13.
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Konferensbidrag (refereegranskat)abstract
- In Sweden, industrial corporations are required to actively monitor and improve the working environment for their employees according to the provision AFS 1998:1, a document that offers guidelines for maintaining a healthy physical working environment, chiefly by ensuring healthy working postures. This provision was purposely formulated in a very general, nonspecific manner in order to be relevant for a large variety of industries.At certain industrial corporations, corporate-internal procedures for evaluating and monitoring the ergonomic status of the workplace have been developed, usually in order to takeconsideration of the specific conditions of that industrial application. The protocol, method,execution and presentation of the evaluation results may vary. Also, the decision regarding which personnel should carry out the evaluation becomes a poignant question. In this article, which describes a Swedish industrial case study in the automotive sector, a corporate-internal method with a highly specified input protocol was used to evaluate theergonomic status of a production line. At the time, the evaluation was carried out by factory personnel with specific training in using the method. Months later, the same factory segment was re-evaluated by two professional ergonomists from an occupational health service, thistime using the AFS 1998:1 provision as a basis.The article makes an attempt to compare the two methods, finding some similarities and also some interesting differences. However, the main research questions that arise from this work concern the difficulties of choosing the right evaluation method for a large, complex industrialsystem; not only do different evaluation methods tell us different things at different levels of detail, but they also require very different competencies from the persons who perform the evaluation.
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| 3. |
- Bertilsson, Erik, et al.
(författare)
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Creation of the IMMA manikin with consideration of anthropometric diversity
- 2011
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Ingår i: 21st International Conference on Production Research: Innovation in Product and Production, ICPR 2011; Stuttgart; Germany; 31 July 2011 through 4 August 2011. - : Fraunhofer Verlag. - 9783839602935 - 3839602939
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Konferensbidrag (refereegranskat)abstract
- Digital human modelling (DHM) systems are used to simulate production processes and analyse the human-machine interaction, particularly at early development stages. Consideration of anthropometric variation is central in DHM simulations due to the necessity of ensuring intended accommodation levels. This paper describes the process of how digital human models are created and defined within the IMMA software. The process begins with the definition of a number of key measurements, which acts as the basis for the definition of several boundary manikins using a confidence ellipsoid methodology. These manikins represents the appropriate confidence region and hence the anthropometric diversity. Key measurements are then entered into regression equations to define the complete set of measurements for each manikin. These measurements are based on the appropriate ISO-standard. Finally, measurements are used to define the size and alignment of each segment in the biomechanical model of the manikin. The manikins are then used to automatically simulate and analyse human-machine interaction.
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| 4. |
- Blomé, Mikael, et al.
(författare)
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Identifying time-consuming human modelling tool activities
- 2006
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to identify and measure time-consuming human modelling tool activities. Five human modelling tool users at Volvo were observed for five days each. The results showed a wide distribution of both indirect and direct working tasks, as well as non-value added tasks such as waiting time. Most of the activities identified appear to be necessary to perform human modelling simulations of high quality. However, the time distribution could be questioned to some extent. There are many activities associated with communication, including a variety of contacts and meetings, where there appears to be potential to increase efficiency.
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| 5. |
- Blomé, Mikael, et al.
(författare)
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Structured time observation of human modelling tool users' activites.
- 2006
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Ingår i: In: Proceedings of 16th Triennial World Congress on Ergonomics, International Ergonomics Association, 2006, July 10-14, Maastricht, The Netherlands..
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Konferensbidrag (refereegranskat)abstract
- Most statements regarding human modeling tools efficiency are based on perceived time. No structured timeobservation of task activities performed by a simulation engineers working with the tools are previous performed.The aim of the study is to identify digital human modelling tool users’ activates and measure the time distributionof the activities. Furthermore, measured time distribution is compared with users perceived time distribution.Five simulation engineers at Volvo were observed for five days each. The simulation engineers’ activities can becategorised in twelve groups. The direct value added work and the indirect value added work important for a newintroduced tool were of similar size as direct value added work for a vehicle disassembly worker. Waiting time, theresimulation is out of control e.g. waiting for information from colleague and computer processor, was perceived muchlonger compared to measured time.The human modelling tool seems to have matured and most of the activities identified seems to be necessary to perform human modelling simulations of high quality; however the time distribution could to some extend be questioned. There are a lot of activities associated with communication, i.e. different kinds of contacts and meetings. Therefore it appears to be a potential to increase efficiency with respect to communication.
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| 6. |
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| 7. |
- Dahlman-Höglund, Anna, 1964, et al.
(författare)
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Antibodies given orally in the neonatal period can affect the immune response for two generations: evidence for active maternal influence on the newborn's immune system.
- 1999
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Ingår i: Scandinavian journal of immunology. - 0300-9475. ; 50:6, s. 651-6
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Tidskriftsartikel (refereegranskat)abstract
- Two day old Wistar rats were tube fed with 1 or 10 micrograms of a mouse IgG1 monoclonal anti-idiotypic (a-Id) antibody that was directed against an anti-Escherichia coli-K13 capsular polysaccharide antibody. A control group was given 10 micrograms of an unrelated control antibody. Six weeks after the administration of antibodies, the rats were intestinally colonised with an ovalbumin (OVA)-producing E. coli O6K13 strain. At 8 weeks of age, the male rats (first generation) and the offsprings of the female rats (second generation), were parenterally immunised with OVA and dead wild type E. coli O6K13, and the immune response was followed. In the rats of the first generation, there were no major differences between the groups in the immune response to the bacterium. However, the offspring of the neonatally a-Id administered rats had a profoundly affected immune response to the idiotypically connected antigen K13, but also to other antigens on the bacteria. Thus, a-Id treatment in the first generation gave, in the second generation, a greatly enhanced serum antibody response to the spatially related antigens OVA and O6 LPS, as well as to the idiotypically connected antigen K13. Concurrently, the in vitro spleen cell proliferative response to both OVA and the wild type bacterium was lowered. Overall, greater effects were seen with the higher dose of a-Id. In conclusion, our results demonstrate that by giving monoclonal antibodies idiotypically connected to a single bacterial component to neonatal rats, one profoundly influence the immune response also to other-spatially related-bacterial antigens in their offsprings.
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| 8. |
- Gakidou, E., et al.
(författare)
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Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016
- 2017
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Ingår i: Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 390:10100, s. 1345-1422
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Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of risk factor exposure and attributable burden of disease. By providing estimates over a long time series, this study can monitor risk exposure trends critical to health surveillance and inform policy debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2016. This study included 481 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk (RR) and exposure estimates from 22 717 randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources, according to the GBD 2016 source counting methods. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. Finally, we explored four drivers of trends in attributable burden: population growth, population ageing, trends in risk exposure, and all other factors combined. Findings Since 1990, exposure increased significantly for 30 risks, did not change significantly for four risks, and decreased significantly for 31 risks. Among risks that are leading causes of burden of disease, child growth failure and household air pollution showed the most significant declines, while metabolic risks, such as body-mass index and high fasting plasma glucose, showed significant increases. In 2016, at Level 3 of the hierarchy, the three leading risk factors in terms of attributable DALYs at the global level for men were smoking (124.1 million DALYs [95% UI 111.2 million to 137.0 million]), high systolic blood pressure (122.2 million DALYs [110.3 million to 133.3 million], and low birthweight and short gestation (83.0 million DALYs [78.3 million to 87.7 million]), and for women, were high systolic blood pressure (89.9 million DALYs [80.9 million to 98.2 million]), high body-mass index (64.8 million DALYs [44.4 million to 87.6 million]), and high fasting plasma glucose (63.8 million DALYs [53.2 million to 76.3 million]). In 2016 in 113 countries, the leading risk factor in terms of attributable DALYs was a metabolic risk factor. Smoking remained among the leading five risk factors for DALYs for 109 countries, while low birthweight and short gestation was the leading risk factor for DALYs in 38 countries, particularly in sub-Saharan Africa and South Asia. In terms of important drivers of change in trends of burden attributable to risk factors, between 2006 and 2016 exposure to risks explains an 9.3% (6.9-11.6) decline in deaths and a 10.8% (8.3-13.1) decrease in DALYs at the global level, while population ageing accounts for 14.9% (12.7-17.5) of deaths and 6.2% (3.9-8.7) of DALYs, and population growth for 12.4% (10.1-14.9) of deaths and 12.4% (10.1-14.9) of DALYs. The largest contribution of trends in risk exposure to disease burden is seen between ages 1 year and 4 years, where a decline of 27.3% (24.9-29.7) of the change in DALYs between 2006 and 2016 can be attributed to declines in exposure to risks. Interpretation Increasingly detailed understanding of the trends in risk exposure and the RRs for each risk-outcome pair provide insights into both the magnitude of health loss attributable to risks and how modification of risk exposure has contributed to health trends. Metabolic risks warrant particular policy attention, due to their large contribution to global disease burden, increasing trends, and variable patterns across countries at the same level of development. GBD 2016 findings show that, while it has huge potential to improve health, risk modification has played a relatively small part in the past decade. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 9. |
- Hanson, Lars, et al.
(författare)
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Design concept evaluation in digital human modeling tools
- 2022
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Ingår i: Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022), August 29–30, 2022, Iowa City, Iowa, USA. - : University of Iowa Press. - 9780984037841 ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- In the design process of products and production systems, the activity to systematically evaluate initial alternative design concepts is an important step. The digital human modeling (DHM) tools include several different types of assessment methods in order to evaluate product and production systems. Despite this, and due to the fact that a DHM tool in essence is a computer-supported design and analysis tool, none of the DHM tools provide the functionality to, in a systematic way, use the results generated in the DHM tool to compare design concepts between each other. The aim of this paper is to illustrate how a systematic concept evaluation method is integrated in a DHM tool, and to exemplify how it can be used to systematically assess design alternatives. Pugh´s method was integrated into the IPS software with LUA scripting to systematically compare design concepts. Four workstation layout concepts were generated by four engineers. The four concepts were systematically evaluated with two methods focusing on human well-being and two methods focusing on system performance and cost. The result is very promising. The demonstrator illustrates that it is possible to perform a systematic concept evaluation based on human well-being, overall system performance, and other parameters, where some of the data is automatically provided by the DHM tool and other data manually. The demonstrator can also be used to evaluate only one design concept, where it provides the software user and the decision maker with an objective and visible overview of the success of the design proposal from the perspective of several evaluation methods.
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| 10. |
- Hanson, Lars, 1970, et al.
(författare)
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IMMA – Intelligently Moving Manikin – Project Status
- 2010
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Ingår i: Proceedings of 3rd Applied Human Factors and Ergonomics (AHFE) International Conference 2010, Karwowski, W. and Salvendy, G. (Eds.), USA. - 9780979643545
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Konferensbidrag (refereegranskat)
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| 11. |
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| 12. |
- Hanson, Lars, et al.
(författare)
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Integrating Physical Load Exposure Calculations and Recommendations in Digitalized Ergonomics Assessment Processes
- 2022
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Ingår i: SPS2022. - Amsterdam; Berlin; Washington, DC : IOS Press. - 9781643682686 - 9781643682693 ; , s. 233-239
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Konferensbidrag (refereegranskat)abstract
- The type of ergonomics assessment methods typically used in digital human modelling (DHM) tools and automated assessment processes were rather developed to be used by ergonomists to assess ergonomics by observing the characteristics of the work. Direct measurement methods complement observation methods. Direct measurement methods have a design that suits being implemented into DHM tools. A drawback of direct measurement methods is that they traditionally do not include action levels. However, action levels in direct measurement methods have recently been suggested. The aim of this paper is to illustrate how these recent physical load exposure calculations and recommendations can be integrated in a DHM tool and in an automated assessment process. A demonstrator solution was developed that inputs exposure data from simulations in the DHM tool IPS IMMA as well as exposure data that originate from tracking real workers’ motions, using the motion capture system Xsens MVN. The demonstrator was applied in two use cases: one based on predicted human motions and one based on captured human motions. In the demonstrator, head posture, upper left and right arm posture and velocity, as well as left and right wrist velocity were calculated. Exposure data were compared with action levels, and extreme action levels were indicated by colouring the information. The results are promising, and the demonstrator illustrates that it is possible to follow the trends in Industry 4.0 and Industry 5.0 to automate and digitalize ergonomics assessment processes in industry.
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| 13. |
- Högberg, Dan, et al.
(författare)
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Representing the elderly in digital human modelling
- 2008
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Ingår i: The 40th annual Nordic Ergonomic Society Conference, NES 2008, Reykjavík, Iceland, August 11-13.. - Kópavogur : Vinnuvistfræðifélag Íslands.
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Konferensbidrag (refereegranskat)abstract
- Digital human modelling (DHM) tools have been introduced in industry, mainly in automotive, aerospace and industrial engineering, to facilitate a proactive and efficient consideration of ergonomics in the design process. The employment of DHM tools in the health care sector calls for customisation work to be carried out in order to make the tools fit the design activities. The human model, i.e. the computer manikin, needs to be modified since it has the characteristics and appearance of an able healthy young or middle-aged human, but the resident or patient is frequently an elderly person with impairments of some kind. This paper suggests concepts and structures for assigning the computer manikins characteristics of the elderly. These changes are made by the modification of anthropometric and joint range of motion data in the DHM tool, and by assigning narrative descriptions to themanikins and more age-corresponding appearances. The objective is to define a manageable number of representative manikins that will support a proactive and user-centred design process in the health care industry, and in other types of design processes for the elderly, or in an inclusive design context.
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| 14. |
- Iriondo Pascual, Aitor, 1993-, et al.
(författare)
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Using time-based musculoskeletal risk assessment methods to assess worker well-being in optimizations in a welding station design
- 2022
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Ingår i: Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022), August 29–30, 2022, Iowa City, Iowa, USA. - : University of Iowa Press. - 9780984037841 ; , s. 1-13
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Konferensbidrag (refereegranskat)abstract
- Simulation using virtual models is used widely in industries because it enables efficient creation, testing, and optimization of the design of products and production systems in virtual worlds. Simulation is also used in the design of workstations to assess worker well-being by using digital human modeling (DHM) tools. DHM tools typically include musculoskeletal risk assessment methods, such as RULA, REBA, OWAS, and NIOSH Lifting Equation, that can be used to study, analyze, and evaluate the risk of work-related musculoskeletal disorders of different design solutions in a proactive manner. However, most musculoskeletal risk assessment methods implemented in DHM tools are in essence made to assess static instances only. Also, the methods are typically made to support manual observations of the work rather than by algorithms in a software. This means that, when simulating full work sequences to evaluate manikins’ well-being, using these methods become problematic in terms of the legitimacy of the evaluation results. In addition to that, to consider objectives in optimizations, they should be measurable with real numbers, which most of musculoskeletal risk assessment methods cannot provide when simulating full work sequences.In this study, we implemented the musculoskeletal risk assessment method OWAS in a digital tool connected to the DHM tool IPS IMMA. We applied the Lundqvist index on top of the OWAS whole body risk category score. This gave us an integer of the time-based ergonomic load for a specific simulation sequence, enabling us to qualitatively compare different design solutions. Using this approach, we performed an optimization in a welding gun workstation to improve the design of the workstation. The results show that using time-based musculoskeletal risk assessment methods as objective functions in optimizations in DHM tools can provide valuable decision support in finding solutions for workstation designs that consider worker well-being.
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| 15. |
- Johansson, Björn, 1975, et al.
(författare)
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Power Level Sampling of Metal Cutting Machines for Data Representation in Discrete Event Simulation
- 2015
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 53:23, s. 7060-7070
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Tidskriftsartikel (refereegranskat)abstract
- An extension to the application area for discrete event simulation (DES) has been ongoing since the last decade and focused only on economic aspects to include ecologic sustainability. With this new focus, additional input parameters, such as electrical power consumption of machines, are needed. This paper aim at investigating how NC machine power consumption should be represented in simulation models of factories. The study includes data-sets from three different factories. One factory producing truck engine blocks, one producing brake disc parts for cars and one producing forklift components. The total number of data points analysed are more than 2,45,000, where of over 1,11,000 on busy state for 11 NC machines. The low variability between busy cycles indicates that statistical representations are not adding significant variability. Furthermore, results show that non-value-added activities cause a substantial amount of the total energy consumption, which can be reduced by optimising the production flow using dynamic simulations such as DES.
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| 16. |
- Laring, Jonas, 1951, et al.
(författare)
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Simulation for manufacturing engineering (ViPP)
- 2005
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; Digital Human Modeling for Design and Engineering Symposium
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this project is to develop methodologies and supportive tools to handle introduction and administration of ergonomics simulation tools for manufacturing engineering. The main result will be a web-based handbook for effective use of digital human modelling tools inside companies and between suppliers and companies. ViPP is divided in three parts: Part A: Studies will be done with the purpose to advise on proper content of input data and on method for assessment of simulations' results. Part B: Studies will be done in order to check reliability of used digital human tools: (1) intra- and inter-individual differences concerning simulation results, (2) vision analysis and (3) the importance of the digital human model appearance/representation on simulation results. Part C: A handbook will be written on virtual production planning for pre production engineers, designers and decision makers. Copyright © 2005 SAE International.
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| 17. |
- Lin, Xiao Ping, et al.
(författare)
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Local allergic reaction in food-hypersensitive adults despite a lack of systemic food-specific IgE
- 2002
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Ingår i: J Allergy Clin Immunol. ; 109:5 Pt 1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Objective tools are lacking for the diagnosis of local gastrointestinal inflammatory reactions in skin prick test (SPT)-negative and serum IgE antibody (s-IgE Ab)-negative patients with suspected food allergy. OBJECTIVE: The purpose of this investigation was to evaluate the presence of eosinophils, T cells, local IgE-bearing cells, IL-4, and IFN-gamma in small intestinal biopsy specimens from adult SPT-negative/s-IgE Ab-negative patients with food allergy during symptomatic and nonsymptomatic periods. METHODS: Fourteen patients with food allergy-related gastrointestinal symptoms confirmed by double-blinded, placebo-controlled food challenge (DBPCFC) were investigated. Eleven of the patients were SPT-negative and s-IgE Ab-negative. Sex- and age-matched healthy volunteers were used as controls. Duodenal biopsies were studied with immunostaining through use of a panel of mouse monoclonal antibodies specific for eosinophils, CD3, CD4, CD8, IgE, IL-4, and IFN-gamma. RESULTS: Significant increases in numbers of MBP(+) eosinophils, IgE-bearing cells, and T cells were found in the duodenal mucosa of the patients when they were symptomatic in comparison with when they were asymptomatic and in comparison with healthy controls. Numbers of IL-4(+) cells were increased and numbers of IFN-gamma(+) cells were reduced in the patients when they were symptomatic in comparison with when they were asymptomatic and in comparison with the controls. There were no differences in total s-IgE levels between any of the groups. CONCLUSION: A significant correlation was found between the appearance of symptoms of food hypersensitivity and the duodenal presence of IgE-bearing cells, activated eosinophils, and T cells in patients with negative SPT results and negative s-IgE Ab to the offending food. We suggest that a localized IgE-mediated response caused the gastrointestinal symptoms seen in these patients.
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| 18. |
- Lämkull, Dan, 1966, et al.
(författare)
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A comparative study of digital human modelling simulation results and their outcomes in reality: A case study within manual assembly of automobiles
- 2008
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 39, s. 428-441
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to examine to what extent ergonomics simulations of manual assembly tasks correctly predict the real outcomes in the plants and if recommended measures originating from ergonomics simulations are taken into consideration. 155 ergonomics simulation cases were used in the study and all cases were performed by nine simulation engineers at Volvo Car Corporation in Gothenburg. The evaluations of the ergonomics conditions of the simulated tasks were done by six professional ergonomists working at Volvo Car Corporation in Gothenburg. The results show that digital human modelling tools (DHM-tools) are useful for the purpose ofproviding designs for standing and unconstrained working postures. Furthermore, the design of various auxiliary devices and their needed space for movements is a prevalent use of DHM-tools. However, the study also identifies areas that require additional developmentin order to further improve the digital human modelling tools’ possibility to correctly predict a work task’s real outcome, i.e. hand access, push pressure and pull forces, leaning and balance behaviour and field of vision. Moreover, a better feedback of product and process changes and a more careful order desription of simulation cases to the simulation engineers would lead to improved simulation results in current and future projects.Relevance to industry:DHM-tools are increasingly the major means used to perform ergonomics analyses of manual assembly tasks in the automotive industry, but there is still a need for improvments of the tools. It is of great importance to disseminate end users’ experiences of the use of different DHM-tools so these can be developed and applied in a more efficient way
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| 19. |
- Lämkull, Dan, 1966, et al.
(författare)
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Consistency in figure posturing results within and between simulation engineers
- 2006
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Konferensbidrag (refereegranskat)abstract
- This paper presents the results of an effort to compare figure posturing results within and between simulation engineers. The simulation engineers simulated four manual tasks. Alternately they used a posture prediction tool, and alternately they were only allowed to apply manual adjustments of the body angles. The simulation engineers repeated each task six times and always with at least six days between each occasion, to minimize the subject's rememberance of how she/he carried out the cases. Results show that the use of a posture prediction tool, in such complex tasks as the study includes, neither reduces needed time to fulfill a simulation, nor differences within or between simulation engineers. Differences in simulation results often originate from the different assumptions the simulation engineers have of the task when positioning the manikins. The differences could be minimized by a more careful orderer description and by such activities as simulation engineering days at assembly plants and by bringing the people working with human simulation tools together in the organization. Copyright © 2006 SAE International.
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| 20. |
- Lämkull, Dan, 1966, et al.
(författare)
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Digital Human Models' Appearance Impact on Observers' Ergonomic Assessment
- 2005
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this paper is to investigate whether different appearance modes of the digital human models (DHM or manikins) affect the observers when judging a working posture. A case where the manikin is manually assembling a battery in the boot with help of a lifting device is used in the experiment. 16 different pictures were created and presented for the subjects. All pictures have the same background, but include a unique posture and manikin appearance combination. Four postures and four manikin appearances were used. The subjects were asked to rank the pictures after ergonomic assessment based on posture of the manikin. Subjects taking part in the study were either manufacturing engineering managers, simulation engineers or ergonomists. Results show that the different appearance modes affect the ergonomic judgment. A more realistic looking manikin is rated higher than the very same posture visualized with a less natural appearance. Therefore, it is important to educate human simulation tool users to always combine visualizations (pictures) with an objective ergonomic evaluation method.
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| 21. |
- Lämkull, Dan, 1966, et al.
(författare)
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The influence of virtual human model appearance on visual ergonomics posture evaluation.
- 2007
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 1872-9126 .- 0003-6870. ; 38:6, s. 713-722
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate whether the appearance of virtual human models influences observers when judging a working posture. A task in which a manikin is manually assembling a car battery was used in the experiment. In total, 16 different pictures were presented to the subjects. All pictures had the same background, but included a unique posture and manikin appearancecombination. 24 subjects consisting of manufacturing managers, simulation engineers and ergonomists were asked to rate and rank the pictures. The results showed that the virtual human model appearance influenced subjects when they rated pictures one by one: a more realistic manikin was rated higher than the identical posture visualized with a less natural appearance. This appearance effect was notseen when subjects ranked the pictures while looking at all of them at the same time. The study demonstrates that the human modelling tool used when showing and visually evaluating results makes a difference. To minimize subjective effects, a combination of visualizations and objective ergonomic assessment methods is recommended.
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| 22. |
- Lämkull, Dan, 1966, et al.
(författare)
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Uniformity in manikin posturing: A comparison between posture prediction and manual joint manipulation
- 2008
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Ingår i: International Journal of Human Factors Modelling and Simulation. - 1742-5549. ; 1:2, s. 225-243
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of a comparison of manikin posturing within and between simulation engineers. Five simulation engineers were asked to simulate and visualize four manual assembly cases. They repeated each task six times, three times with a posture prediction tool and three times with manual adjustment of the body angles. The results show that the posture prediction tool was not used in an optimal manner. Although the prediction tool was quick at suggesting a likely posture, the simulation engineers were reluctant to consider a simulation task completed until the manikin’s posture was realistic in all aspects, not only in the configurations for the major body joints postures but also for fingers, wrists and feet. This fine tuning of fingers is performed with manual manipulation of joints and cancels out the time gained with the posture prediction tool. The fine tuning does not affect the results in objective evaluation methods. Therefore, a lower acceptance level of correctness among managers, simulation engineers and ergonomic specialists is desired, or a shift from visualization to simulation is necessary. Manikin postures differ between simulation engineers. A posture variation exists and this variation in working behaviour should be accepted and simulated. However, simulation engineers also need more extensive knowledge of how workers actually behave on the assembly line; study visits are thus recommended. A shift is also recommended from simulations and visualizations of normal working behaviours to that of ergonomically correct behaviours. This comparison of manikin posturing within and between simulation engineers is an attempt to understand the use of the tool in a practical sense. The comparison indicates that if a posture prediction tool is to be beneficial for the whole organisation, all disciplines involved in the use of manikins must accept simulation results with postures containing some non-cosmetic elements. It is not until such an acceptance is achieved that the successful use of a posture prediction tool will become a reality.
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| 23. |
- Magnusson, Jenny, 1970, et al.
(författare)
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Seasonal intestinal inflammation in patients with birch pollen allergy
- 2003
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Ingår i: J Allergy Clin Immunol. ; 112:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The pathophysiologic interactions of inflammatory reactions between the mucosa of the respiratory tract and that of the gastrointestinal tract in individuals with allergy are poorly studied, despite the fact that allergic symptoms in the airways and the gastrointestinal tract might arise in the same patient. OBJECTIVE: The objective of this study was to examine the inflammatory response histologically by enumerating eosinophils, IgE+ cells, and T cells in duodenal biopsy specimens in adult patients with IgE-mediated birch pollen allergy during the birch pollen season and off-season. METHODS: Nine patients with birch pollen allergy verified by skin prick test and serum IgE antibodies were investigated toward the end of the birch pollen season and again 6 months later (off-season). Duodenal biopsy specimens were obtained and studied by immunostaining for the eosinophil major basic protein (MBP), IgE, and CD3+ T cells. RESULTS: Oral allergy syndrome to birch-associated foods was present in all patients as indicated by questionnaire. Duodenal increases of MBP+ eosinophils and IgE-bearing cells were found in the patients during the birch pollen season as compared with off-season. No seasonal differences in the T-cell numbers in these patients were seen. Off-season, there was no significant difference between the patients and the control subjects regarding the intestinal frequencies of MBP+ eosinophils, mucosal IgE+ cells, and T cells. CONCLUSION: Birch pollen exposure triggered a local inflammation with an increase in duodenal eosinophils and IgE-carrying mast cells in patients with allergy. Our study gives evidence for the interplay between immunologically active cells in the airways and the gut.
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| 24. |
- Mårdberg, Peter, et al.
(författare)
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Introducing a Formal High-Level Language for Instructing Automated Manikins
- 2013
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Ingår i: 2nd International Digital Human Modeling.
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Konferensbidrag (refereegranskat)abstract
- Digital Human Modeling programs are important tools in virtual manufacturing that allow simulation of manual assembly work, long before any physical product has been built. By investigating the logistics, ergonomics and the interaction among the workers at an early stage, it may be possible to reduce the cost of design changes, increase the quality and to decrease the ramp-up time of a manufacturing process. However, far from all assembly operations are simulated, even if all the necessary data is available. One reason is the tedious work required to setup and to define all the motions needed by a manikin to perform a simulation. In each simulation, the manikin must be adjusted into the desired posture and the user must ensure that balance is held and that it avoids collision with objects in the environment. Thus, even a small case may be time consuming to simulate. This shows that there is a need of an easier way of instructing the manikins. In this work we propose a new formal high-level language for controlling an automated manikin. The language instructions are structured by a grammar, which defines a hierarchical tree for the manikin instructions. The low-level instructions contains basic functionality for maneuvering the manikin, such as Move, Position and Grasp, and higher levels contain more abstract instructions such as Get and Assemble. Thus, the high-level instructions define sequences of other instructions, whereas a low-level instruction corresponds to a direct instruction of the manikin. The set of available instructions that the manikin may perform during a simulation depends on the current state of the manikin and the objects at the assembly station. Thus, properties of objects, such as grasping and mating points, also help define the set of available instructions for the manikin. The order in which the different parts in the assembly operations have to be connected may also be considered when constructing instruction sequences for the manikin. Furthermore, the instruction sequences may be formally verified to ensure that the manikin only performs valid instructions. The language have been implemented in the manikin simulation software IMMA and tested on elementary cases with relevance to industrial applications. The results show that fewer steps are needed to perform a realistic simulation when the language is used compared to manually instructing the manikin. Furthermore, it is also shown that the instructions generated by the language are formally correct.
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| 25. |
- Mårdberg, Peter, 1980, et al.
(författare)
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Using a Formal High-level Language to Instruct Manikins to Assemble Cables
- 2014
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 23:C, s. 29-34
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Konferensbidrag (refereegranskat)abstract
- In this paper, a formal high-level language is used to generate simulations where a manikin assembles flexible cables. The language generates assembly instructions for the manikin, which automatically performs the corresponding assembly motion with as good ergonomic as possible. Due to weight, stiffness and narrow regions, it may be difficult to perform an assembly of the cable. Our approach allows us to verify that it may be performed in an ergonomically sound way. The generated instructions are formally verified to ensure that assembly order is held and to prevent erroneous assembly states. The simulations have been made on industrial test cases.
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| 26. |
- Nourmohammadi, Amir, et al.
(författare)
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Multi-objective optimization of mixed-model assembly lines incorporating musculoskeletal risks assessment using digital human modeling
- 2023
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 47, s. 71-85
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Tidskriftsartikel (refereegranskat)abstract
- In line with Industry 5.0, ergonomic factors have recently received more attention in balancing assembly lines to enhance the human-centric aspect. Meanwhile, today’s mass-customized trend yields manufacturers to offset the assembly lines for different product variants. Thus, this study addresses the mixed-model assembly line balancing problem (MMALBP) by considering worker posture. Digital human modeling and posture assessment technologies are utilized to assess the risks of work-related musculoskeletal disorders using a method known as rapid entire body analysis (REBA). The resulting MMALBP is formulated as a mixed-integer linear programming (MILP) model while considering three objectives: cycle time, maximum ergonomic risk of workstations, and total ergonomic risks. An enhanced non-dominated sorting genetic algorithm (E-NSGA-II) is developed by incorporating a local search procedure that generates neighborhood solutions and a multi-criteria decision-making mechanism that ensures the selection of promising solutions. The E-NSGA-II is benchmarked against Epsilon-constraint, MOGA, and NSGA-II while solving a case study and also test problems taken from the literature. The computational results show that E-NSGA-II can find promising Pareto front solutions while dominating the considered methods in terms of performance metrics. The robustness of E-NSGA-II results is evaluated through one-way ANOVA statistical tests. The analysis of results shows that a smooth distribution of time and ergonomic loads among the workstations can be achieved when all three objectives are simultaneously considered.
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| 27. |
- Skoogh, Anders, 1980, et al.
(författare)
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Data Requirements and Representation for Simulation of Energy Consumption in Production Systems
- 2011
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Ingår i: In Proceedings of the 44th CIRP Conference on Manufacturing Systems.
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Konferensbidrag (refereegranskat)abstract
- Recently, the application area for Discrete Event Simulation has been extended from focus on economical aspects to include ecologic sustainability. Therefore, this paper aims to specify how new input parameters, such as electrical power, should be represented in simulation models. The study includes more than 230 000 power measurements from a production line with five multi-operational machines. The variability between production cycles is low, which indicates that statistical representations are unnecessary. Furthermore, results show that 33% of the total energy consumption stems from non-value-added activities, which can be reduced by optimizing the production flow using dynamic simulations.
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| 28. |
- Vos, T., et al.
(författare)
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Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016
- 2017
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Ingår i: Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 390:10100, s. 1211-1259
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Tidskriftsartikel (refereegranskat)abstract
- Background As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016. Methods We estimated prevalence and incidence for 328 diseases and injuries and 2982 sequelae, their non-fatal consequences. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between incidence, prevalence, remission, and cause of death rates for each condition. For some causes, we used alternative modelling strategies if incidence or prevalence needed to be derived from other data. YLDs were estimated as the product of prevalence and a disability weight for all mutually exclusive sequelae, corrected for comorbidity and aggregated to cause level. We updated the Socio-demographic Index (SDI), a summary indicator of income per capita, years of schooling, and total fertility rate. GBD 2016 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Findings Globally, low back pain, migraine, age-related and other hearing loss, iron-deficiency anaemia, and major depressive disorder were the five leading causes of YLDs in 2016, contributing 57.6 million (95% uncertainty interval [UI] 40.8-75.9 million [7.2%, 6.0-8.3]), 45.1 million (29.0-62.8 million [5.6%, 4.0-7.2]), 36.3 million (25.3-50.9 million [4.5%, 3.8-5.3]), 34.7 million (23.0-49.6 million [4.3%, 3.5-5.2]), and 34.1 million (23.5-46.0 million [4.2%, 3.2-5.3]) of total YLDs, respectively. Age-standardised rates of YLDs for all causes combined decreased between 1990 and 2016 by 2.7% (95% UI 2.3-3.1). Despite mostly stagnant age-standardised rates, the absolute number of YLDs from non-communicable diseases has been growing rapidly across all SDI quintiles, partly because of population growth, but also the ageing of populations. The largest absolute increases in total numbers of YLDs globally were between the ages of 40 and 69 years. Age-standardised YLD rates for all conditions combined were 10.4% (95% UI 9.0-11.8) higher in women than in men. Iron-deficiency anaemia, migraine, Alzheimer's disease and other dementias, major depressive disorder, anxiety, and all musculoskeletal disorders apart from gout were the main conditions contributing to higher YLD rates in women. Men had higher age-standardised rates of substance use disorders, diabetes, cardiovascular diseases, cancers, and all injuries apart from sexual violence. Globally, we noted much less geographical variation in disability than has been documented for premature mortality. In 2016, there was a less than two times difference in age-standardised YLD rates for all causes between the location with the lowest rate (China, 9201 YLDs per 100 000, 95% UI 6862-11943) and highest rate (Yemen, 14 774 YLDs per 100 000, 11 018-19 228). Interpretation The decrease in death rates since 1990 for most causes has not been matched by a similar decline in age-standardised YLD rates. For many large causes, YLD rates have either been stagnant or have increased for some causes, such as diabetes. As populations are ageing, and the prevalence of disabling disease generally increases steeply with age, health systems will face increasing demand for services that are generally costlier than the interventions that have led to declines in mortality in childhood or for the major causes of mortality in adults. Up-todate information about the trends of disease and how this varies between countries is essential to plan for an adequate health-system response. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 29. |
- Zhu, Xiaomeng, et al.
(författare)
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Surface Defect Detection with Limited Training Data : A Case Study on Crown Wheel Surface Inspection
- 2023
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Ingår i: Procedia CIRP. - : Elsevier. - 2212-8271 .- 2212-8271. ; 120, s. 1333-1338, s. 1333-1338
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to automatic surface defect detection by a deep learning-based object detection method, particularly in challenging scenarios where defects are rare, i.e., with limited training data. We base our approach on an object detection model YOLOv8, preceded by a few steps: 1) filtering out irrelevant information, 2) enhancing the visibility of defects, namely brightness contrast, and 3) increasing the diversity of the training data through data augmentation. We evaluated the method in an industrial case study of crown wheel surface inspection in detecting Unclean Gear as well as Deburring defects, resulting in promising performances. With the combination of the three preprocessing steps, we improved the detection accuracy by 22.2% and 37.5% respectively while detecting those two defects. We believe that the proposed approach is also adaptable to various applications of surface defect detection in other industrial environments as the employed techniques, such as image segmentation, are available off the shelf.
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| 30. |
- Zhu, Xiaomeng, et al.
(författare)
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Towards Sim-to-Real Industrial Parts Classification with Synthetic Dataset
- 2023
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Ingår i: Proceedings, 2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops. - : IEEE. - 9798350302493 - 9798350302509 ; , s. 4454-4463, s. 4454-4463
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Konferensbidrag (refereegranskat)abstract
- This paper is about effectively utilizing synthetic data for training deep neural networks for industrial parts classification, in particular, by taking into account the domain gap against real-world images. To this end, we introduce a synthetic dataset that may serve as a preliminary testbed for the Sim-to-Real challenge; it contains 17 objects of six industrial use cases, including isolated and assembled parts. A few subsets of objects exhibit large similarities in shape and albedo for reflecting challenging cases of industrial parts. All the sample images come with and without random backgrounds and post-processing for evaluating the importance of domain randomization. We call it Synthetic Industrial Parts dataset (SIP-17). We study the usefulness of SIP-17 through benchmarking the performance of five state-of-the-art deep network models, supervised and self-supervised, trained only on the synthetic data while testing them on real data. By analyzing the results, we deduce some insights on the feasibility and challenges of using synthetic data for industrial parts classification and for further developing larger-scale synthetic datasets. Our dataset † and code ‡ are publicly available.
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| 31. |
- Zillikens, M. C., et al.
(författare)
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Large meta-analysis of genome-wide association studies identifies five loci for lean body mass
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Lean body mass, consisting mostly of skeletal muscle, is important for healthy aging. We performed a genome-wide association study for whole body (20 cohorts of European ancestry with n = 38,292) and appendicular (arms and legs) lean body mass (n = 28,330) measured using dual energy X-ray absorptiometry or bioelectrical impedance analysis, adjusted for sex, age, height, and fat mass. Twenty-one single-nucleotide polymorphisms were significantly associated with lean body mass either genome wide (p < 5 x 10(-8)) or suggestively genome wide (p < 2.3 x 10(-6)). Replication in 63,475 (47,227 of European ancestry) individuals from 33 cohorts for whole body lean body mass and in 45,090 (42,360 of European ancestry) subjects from 25 cohorts for appendicular lean body mass was successful for five single-nucleotide polymorphisms in/ near HSD17B11, VCAN, ADAMTSL3, IRS1, and FTO for total lean body mass and for three single-nucleotide polymorphisms in/ near VCAN, ADAMTSL3, and IRS1 for appendicular lean body mass. Our findings provide new insight into the genetics of lean body mass.
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| 32. |
- Örtengren, Roland, 1942, et al.
(författare)
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Digital human modeling simulation results and their outcomes in reality: A comparative study within manual assembly of automobiles
- 2009
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Ingår i: SAE Technical Papers. - : SAE International. - 0148-7191 .- 2688-3627. ; 2009
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Konferensbidrag (refereegranskat)abstract
- The objective of this study was to examine to what extent ergonomics simulations of manual assembly tasks correctly predict the real outcomes in automotive assembly plants, and if recommended measures originating from ergonomics simulations are considered. 155 ergonomics simulation cases done by nine simulation engineers at Volvo Car Corporation in Gothenburg were used in the study. The evaluations of the ergonomics conditions in reality of the cases were done by six professional ergonomists working in the company. The results show that digital human modelling tools are useful for providing designs for standing and unconstrained working postures as well as for the design of various auxiliary devices and their needed space for movements. The study also identifies areas that require additional development in order to improve the digital human modelling tools' ability to correctly predict a work task's real outcome. Moreover, a better feedback of product and process changes, and a more careful order description to the simulation engineers, would improve simulation results in current and future projects. Copyright © 2009 SAE International.
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