| 1. |
- Alfelt, Gustav, 1985-, et al.
(författare)
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On the mean and variance of the estimated tangency portfolio weights for small samples
- 2022
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Ingår i: Modern Stochastics: Theory and Applications. - Vilnius : VTeX. - 2351-6054 .- 2351-6046. ; 9:4, s. 453-482
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a sample estimator of the tangency portfolio (TP) weights is con-sidered. The focus is on the situation where the number of observations is smaller than the number of assets in the portfolio and the returns are i.i.d. normally distributed. Under these as-sumptions, the sample covariance matrix follows a singular Wishart distribution and, therefore, the regular inverse cannot be taken. In the paper, bounds and approximations for the first two moments of the estimated TP weights are derived, as well as exact results are obtained when the population covariance matrix is equal to the identity matrix, employing the Moore-Penrose inverse. Moreover, exact moments based on the reflexive generalized inverse are provided. The properties of the bounds are investigated in a simulation study, where they are compared to the sample moments. The difference between the moments based on the reflexive generalized inverse and the sample moments based on the Moore-Penrose inverse is also studied.
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| 2. |
- Frid, Emma, et al.
(författare)
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An Exploratory Study On The Effect Of Auditory Feedback On Gaze Behavior In a Virtual Throwing Task With and Without Haptic Feedback
- 2017
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Ingår i: Proceedings of the 14th Sound and Music Computing Conference. - Espoo, Finland : Aalto University. - 9789526037295 ; , s. 242-249
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Konferensbidrag (refereegranskat)abstract
- This paper presents findings from an exploratory study on the effect of auditory feedback on gaze behavior. A total of 20 participants took part in an experiment where the task was to throw a virtual ball into a goal in different conditions: visual only, audiovisual, visuohaptic and audio- visuohaptic. Two different sound models were compared in the audio conditions. Analysis of eye tracking metrics indicated large inter-subject variability; difference between subjects was greater than difference between feedback conditions. No significant effect of condition could be observed, but clusters of similar behaviors were identified. Some of the participants’ gaze behaviors appeared to have been affected by the presence of auditory feedback, but the effect of sound model was not consistent across subjects. We discuss individual behaviors and illustrate gaze behavior through sonification of gaze trajectories. Findings from this study raise intriguing questions that motivate future large-scale studies on the effect of auditory feedback on gaze behavior.
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| 3. |
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| 4. |
- Masterton, Malin, 1979-, et al.
(redaktör/utgivare, creator_code:cre_t)
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ORU2015 Örebro University Research Evaluation 2015 : Evaluation Report
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- ORU2015 – Executive SummaryDuring 2015, all research performed from 2008 to 2014 at Örebro University, as well as research at Örebro University Hospital, has been evaluated. This report – ORU2015 – presents the background, planning and implementation of the research assessment and its results. Chapter I includes the panel evaluations, and chapter II presents the bibliometric data. Of the 38 subunits of evaluation, 8 are within the Faculty of Business, Science and Engineering, 17 are within the Faculty of Humanities and Social Sciences, 7 within the Faculty of Medicine and Health, and 6 at Region Örebro County’s University Hospital. The evaluation had a meta-analytical approach (see Annex A), and the external multidisciplinary panel assessed the research in each subunit of evaluation (see Annex B). The panel’s evaluation material consisted of a research overview, documentation on academic staff and competence, as well as on funding, self-evaluations and bibliometric data. The self-evaluations by each subunit addressed (i) scientific quality and scientific impact, (ii) impact and outreach, (iii) internationalisation, and (iv) research – education interaction. Each overarching evaluation unit was also assessed, including a SWOT analysis, by the respective heads of schools and deans. Apart from the self-evaluations, the material was retrieved from the university databases, Web of Science and Academic Archive Online (DiVA). The subunits had the opportunity to update their research information for the research overview prior to making the material available to the panel. The fourteen panellists, representing economics, natural sciences and technology, humanities, social sciences, medicine and health sciences, met for two days in October at Örebro University for the evaluation discussions. The agreed evaluation statements were delivered shortly thereafter. The great variability in the subunits’ scientific practices, scale, and establishment had to be accounted for in the panel evaluations. The evaluation subunits range from very large (up to 60 researchers), to medium sized (about 20 researchers), and to quite small subunits (fewer than nine researchers). The points of reference for the panel’s statements were the (i) quality of research, (ii) research environment and infrastructure, (iii) scientific and social interaction and (iv) future potential. Gradings ranged between Excellent (5) and Insufficient (1). The key data in the bibliometric assessment was scientific impact, vitality, productivity and international visibility, as indicated by the publications of each subunit. It can be seen from the panel statement of a subunit and the matching bibliometric data that these two assessments correspond to a large extent, but not completely.It is concluded from the panel evaluation that there are Excellent (5), Very Good (4), Good (3), Sufficient (2), as well as Insufficient (1) subunits at the university. A majority of the fourteen subunits that performed well (grade 3 – 5) are medium-sized, whilst the majority of the sixteen weakly performing subunits (grade 1 – 2) are small in size. Of course, for the humanities and social sciences, the Web of Science data only contains output to a limited degree. Therefore data from DiVA has been used and compared as well. For some subunits this makes a difference, but of the 16 subunits that show a weak performance according to Web of Science data, ten also perform weakly as shown in DiVA. Only three of these subunits score Good and one Very Good in DiVA.It can be seen from ORU2015 that the research volume, especially expressed in scientific publications per year and citations, has roughly doubled since ÖRE2010. In 2014, the total number of publications in Web of Science by researchers at the university and the university hospital reached some 600 and the number of citations were 14,000 the same year. The ‘findings’ of ORU2015 provide an important basis for decisions by leaders at all levels of the university in terms of strategic planning, support, and development of the research for the future.
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| 5. |
- Muncke, Jane, et al.
(författare)
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Impacts of food contact chemicals on human health : a consensus statement
- 2020
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Ingår i: Environmental Health. - : BioMed Central (BMC). - 1476-069X. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Food packaging is of high societal value because it conserves and protects food, makes food transportable and conveys information to consumers. It is also relevant for marketing, which is of economic significance. Other types of food contact articles, such as storage containers, processing equipment and filling lines, are also important for food production and food supply. Food contact articles are made up of one or multiple different food contact materials and consist of food contact chemicals. However, food contact chemicals transfer from all types of food contact materials and articles into food and, consequently, are taken up by humans. Here we highlight topics of concern based on scientific findings showing that food contact materials and articles are a relevant exposure pathway for known hazardous substances as well as for a plethora of toxicologically uncharacterized chemicals, both intentionally and non-intentionally added. We describe areas of certainty, like the fact that chemicals migrate from food contact articles into food, and uncertainty, for example unidentified chemicals migrating into food. Current safety assessment of food contact chemicals is ineffective at protecting human health. In addition, society is striving for waste reduction with a focus on food packaging. As a result, solutions are being developed toward reuse, recycling or alternative (non-plastic) materials. However, the critical aspect of chemical safety is often ignored. Developing solutions for improving the safety of food contact chemicals and for tackling the circular economy must include current scientific knowledge. This cannot be done in isolation but must include all relevant experts and stakeholders. Therefore, we provide an overview of areas of concern and related activities that will improve the safety of food contact articles and support a circular economy. Our aim is to initiate a broader discussion involving scientists with relevant expertise but not currently working on food contact materials, and decision makers and influencers addressing single-use food packaging due to environmental concerns. Ultimately, we aim to support science-based decision making in the interest of improving public health. Notably, reducing exposure to hazardous food contact chemicals contributes to the prevention of associated chronic diseases in the human population.
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| 6. |
- Sjöqvist, Hugo, 1992-, et al.
(författare)
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An Analysis of Fast Learning Methods for Classifying Forest Cover Types
- 2020
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Ingår i: Applied Artificial Intelligence. - : Taylor & Francis Group. - 0883-9514 .- 1087-6545. ; 34:10, s. 691-709
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Tidskriftsartikel (refereegranskat)abstract
- Proper mapping and classification of Forest cover types are integral in understanding the processes governing the interaction mechanism of the surface with the atmosphere. In the presence of massive satellite and aerial measurements, a proper manual categorization has become a tedious job. In this study, we implement three different modest machine learning classifiers along with three statistical feature selectors to classify different cover types from cartographic variables. Our results showed that, among the chosen classifiers, the standard Random Forest Classifier together with Principal Components performs exceptionally well, not only in overall assessment but across all seven categories. Our results are found to be significantly better than existing studies involving more complex Deep Learning models.
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| 7. |
- Uggla, Ylva, 1960-, et al.
(författare)
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Dissimilar framings of forest biodiversity preservation : Uncertainty and legal ambiguity as contributing factors
- 2016
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Ingår i: Forest Policy and Economics. - : Elsevier. - 1389-9341 .- 1872-7050. ; 62, s. 36-42
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Tidskriftsartikel (refereegranskat)abstract
- Controversies over forestry and environmental issues, including biodiversity, are common. Theory suggests that uncertainty may play a major role in framing biodiversity and its preservation. This paper examines written statements on biodiversity preservation published by two major Swedish organizations, i.e., the Swedish Forest Industries Federation and the Swedish Society for Nature Conservation, with different interests in forest use. Frame analysis suggests that when the actors pursue a certain policy course, both biodiversity-related uncertainty and lack of regulatory clarity are important factors contributing to dissimilar framings. This case study supports the general understanding that biodiversity-related uncertainty can have important implications for biodiversity preservation, in this case, via forest policy and legislation. Scientific uncertainty may allow actors with dissimilar interests in an issue to justify their standpoints. To successfully manage forest biodiversity in the future, legal frameworks must increasingly find ways to accommodate scientific uncertainty, and models must be developed in which stakeholders’ diverging interests and values address uncertainties via dialogue.
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| 8. |
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3rd International Conference on Material Engineering and Advanced Manufacturing Technology, 26–28 April 2019, Shanghai, China
- 2020
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Proceedings (redaktörskap) (refereegranskat)abstract
- We are very pleased to present the proceedings of the 3rd International Conference on Material Engineering and Advanced Manufacturing Technology (MEAMT 2019) that was held successfully under the auspices of IASED in Shanghai, China, April 26-28, 2019.The theme of the conference - Material Engineering and Advanced Manufacturing Technology - is of key importance to the science and technology and a sustainable industrial development. This conference promotes valuable contacts between academia and industry and addresses both basic research and the societal/industrial technological needs within Material Engineering and Advanced Manufacturing Technology.In this era of Industry 4.0, we hope that the conference provided applicable data/information, addressed the issues in the societal/industrial transformation, and facilitated exchange within and between academia and industry.We want to express our gratitude to the program chairs and all members of the advisory, publicity, and technical committees for their valuable time and advices. We are grateful to the world renowned scientists who acted as keynote speakers at the conference.After a rigorous review process, where each paper was reviewed by at least two reviewers, high quality papers were accepted for presentation at this conference. We would like to thank all the reviewers for their time, effort, and for completing their assignments on time albeit tight deadlines.Many thanks to the authors for their valuable contributions and to the attendees for their active participation.Finally, a big thank to the organizers who made this conference to yet another unforgettable experience.Nader AsnafiProfessor of Mechanical Engineering, Örebro University, Sweden Editor of the proceedings of MEAMT 2019 One behalf of the conference committee.
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| 9. |
- Abad, Esteban, et al.
(författare)
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Air monitoring with passive samplers for dioxin-like persistent organic pollutants in developing countries (2017-2019)
- 2021
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Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 287:Pt 1
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Tidskriftsartikel (refereegranskat)abstract
- As part of the global monitoring plan on persistent organic pollutants (GMP) under the Stockholm Convention passive air samplers equipped with polyurethane foam disks (PUFs) were applied to monitor dioxin-like POPs. For sampling, toluene-pretreated PUFs were exposed for three months during two years. Chemical analysis was performed in one accredited expert laboratory using internationally accepted methods; for comparison, all results were normalized to one PUF and 3 month exposure. Total TEQs, using WHO2005-TEFs, were lowest in the Pacific Islands countries (PAC) and had similar mean values in Africa (16.8 pg TEQ/PUF), Asia (16.9 pg TEQ/PUF), and Latin American and Caribbean countries (GRULAC, 13.3 pg TEQ/PUF). Using median values, Asia (13.4 pg TEQ/PUF) and GRULAC (13.1 pg TEQ/PUF) had higher amounts than Africa (6.1 pg TEQ/PUF) and PAC (2.1 pg TEQ/PUF). The contribution of PCDD/PCDF to the total TEQ was 2-3-times higher than from the dl-PCB. Mono-ortho PCB did not play a role in any of the samples. The previous 40 samples during 2010/2011 and the present 195 samples from 2017/2018 did not show a statistical difference (p value = 0.3), only for GRULAC, a downward trend was identified. It is recommended combining 4 PUFs to ‘annual’ samples.
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| 10. |
- Abalos, M., et al.
(författare)
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Results for PCDD/PCDF and dl-PCBs in the first round of UNEPs biennial global interlaboratory assessment on persistent organic pollutants
- 2013
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Ingår i: TrAC. Trends in analytical chemistry. - : Elsevier BV. - 0165-9936 .- 1879-3142. ; 46, s. 98-109
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Tidskriftsartikel (refereegranskat)abstract
- The first worldwide interlaboratory assesment on persistent organic pollutants (POPs) under the Stockholm Convention was organized in the Asian/Pacific, Latin American and African regions during 2009-11.A relatively large number of laboratories reported data for the PCDDs/PCDFs and dioxin-like PCBs, especially in the Asian region. Within the Asian region, several participants used high-resolution GC/high-resolution MS systems optimized for dioxin analysis. The availibility of High-resolution mass spectrometer instrumentation is limited in the Latin America and African regions, although recently several new laboratories for dioxins have started in the Latin American region.
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