scholarly journals Robust Modelling of Additive and Non-additive Variation with Intuitive Inclusion of Expert Knowledge

Author(s):  
Ingeborg Gullikstad Hem ◽  
Maria Lie Selle ◽  
Gregor Gorjanc ◽  
Geir-Arne Fuglstad ◽  
Andrea Riebler

AbstractWe propose a novel Bayesian approach that robustifies genomic modelling by leveraging expert knowledge through prior distributions. The central component is the hierarchical decomposition of phenotypic variation into additive and non-additive genetic variation, which leads to an intuitive model parameterization that can be visualised as a tree. The edges of the tree represent ratios of variances, for example broad-sense heritability, which are quantities for which expert knowledge is natural to exist. Penalized complexity priors are defined for all edges of the tree in a bottom-up procedure that respects the model structure and incorporates expert knowledge through all levels. We investigate models with different sources of variation and compare the performance of different priors implementing varying amounts of expert knowledge in the context of plant breeding. A simulation study shows that the proposed priors implementing expert knowledge improve the robustness of genomic modelling and the selection of the genetically best individuals in a breeding program. We observe this improvement in both variety selection on genetic values and parent selection on additive values; the variety selection benefited the most. In a real case study expert knowledge increases phenotype prediction accuracy for cases in which the standard maximum likelihood approach did not find optimal estimates for the variance components. Finally, we discuss the importance of expert knowledge priors for genomic modelling and breeding, and point to future research areas of easy-to-use and parsimonious priors in genomic modelling.

Genetics ◽  
2021 ◽  
Author(s):  
Ingeborg Gullikstad Hem ◽  
Maria Lie Selle ◽  
Gregor Gorjanc ◽  
Geir-Arne Fuglstad ◽  
Andrea Riebler

Abstract We propose a novel Bayesian approach that robustifies genomic modeling by leveraging expert knowledge (EK) through prior distributions. The central component is the hierarchical decomposition of phenotypic variation into additive and nonadditive genetic variation, which leads to an intuitive model parameterization that can be visualized as a tree. The edges of the tree represent ratios of variances, for example broad-sense heritability, which are quantities for which EK is natural to exist. Penalized complexity priors are defined for all edges of the tree in a bottom-up procedure that respects the model structure and incorporates EK through all levels. We investigate models with different sources of variation and compare the performance of different priors implementing varying amounts of EK in the context of plant breeding. A simulation study shows that the proposed priors implementing EK improve the robustness of genomic modeling and the selection of the genetically best individuals in a breeding program. We observe this improvement in both variety selection on genetic values and parent selection on additive values; the variety selection benefited the most. In a real case study, EK increases phenotype prediction accuracy for cases in which the standard maximum likelihood approach did not find optimal estimates for the variance components. Finally, we discuss the importance of EK priors for genomic modeling and breeding, and point to future research areas of easy-to-use and parsimonious priors in genomic modeling.


2020 ◽  
Vol 13 ◽  
Author(s):  
Gaurav Gaurav ◽  
Abhay Sharma ◽  
G S Dangayach ◽  
M L Meena

Background: Minimum quantity lubrication (MQL) is one of the most promising machining techniques that can yield a reduction in consumption of cutting fluid more than 90 % while ensuring the surface quality and tool life. The significance of the MQL in machining makes it imperative to consolidate and analyse the current direction and status of research in MQL. Objective: This study aims to assess global research publication trends and hot topics in the field of MQL among machining process. The bibliometric and descriptive analysis are the tools that the investigation aims to use for the data analysis of related literature collected from Scopus databases. Methods: Various performance parameters are extracted, such as document types and languages of publication, annual scientific production, total documents, total citations, and citations per article. The top 20 of the most relevant and productive sources, authors, affiliations, countries, word cloud, and word dynamics are assessed. The graphical visualisation of the bibliometric data is presented in terms of bibliographic coupling, citation, and co-citation network. Results: The investigation reveals that the International Journal of Machine Tools and Manufacture (2611 citations, 31 hindex) is the most productive journal that publishes on MQL. The most productive institution is the University of Michigan (32 publications), the most cited country is Germany (1879 citations), and the most productive country in MQL is China (124 publications). The study shows that ‘Cryogenic Machining’, ‘Sustainable Machining’, ‘Sustainability’, ‘Nanofluid’ and ‘Titanium alloy’ are the most recent keywords and indications of the hot topics and future research directions in the MQL field. Conclusion: The analysis finds that MQL is progressing in publications and the emerging with issues that are strongly associated with the research. This study is expected to help the researchers to find the most current research areas through the author’s keywords and future research directions in MQL and thereby expand their research interests.


Author(s):  
Ronald E. Rice ◽  
Simeon J. Yates ◽  
Jordana Blejmar

We conclude the Handbook of Digital Technology and Society by identifying topics that appear in multiple chapters, are more unique to some chapters, and that represent general themes across the material. Each of these is considered separately for the ESRC theme chapters and the non-ESRC chapters. In the ESRC theme chapters, cross-cutting research topics include digital divides and inequalities; data and digital literacy; governance, regulation, and legislation; and the roles and impacts of major platforms. Cross-cutting challenges include methods; theory development, testing, and evaluation; ethics; big data; and multi-platform/holistic studies. Gaps include policy implications, and digital culture. In the non-ESRC chapters, more cross-cutting themes include future research and methods; technology venues; relationships; content and creation; culture and everyday life; theory; and societal effects. More unique, these were digitization of self; managing digital experience; names for the digital/social era; ethics; user groups; civic issues; health, and positive effects. The chapter also shows how the non-ESRC chapters may be clustered together based on their shared themes and subthemes, identifying two general themes of more micro and more macro topics. The identification of both more and less common topics and themes can provide the basis for understanding the landscape of prior research, what areas need to be included in ongoing research, and what research areas might benefit from more attention. The chapter ends with some recommendations for such ongoing and future research in the rich, important, and challenging area of digital technology and society.


Author(s):  
Susanne Scheibe ◽  
Ute Kunzmann ◽  
Paul B. Baltes

In search for concepts that help understand how individuals strive for growth and perfection within the boundaries and constraints of human lives, we describe theory and research on the concepts of wisdom, or expert knowledge about human nature and the life course, and Sehnsucht (life longings), the recurring and strong desire for ideal (utopian), alternative states and expressions of life. Both represent relatively new concepts on the agenda of lifespan research, originating from an interest in identifying major topics of public and humanist discourse about the potentials and constraints of life-span development and finding ways to measure them with the methods of normative psychological science. Despite their complexity and multiple meanings, progress has been made in the theory-driven operationalization of wisdom and life longings, allowing new insights into their ontogenesis and role for positive development. Emerging research shows that wisdom and life longings do not directly promote a hedonic life orientation or happiness: neither the insight that life is incomplete (wisdom) nor the experience of this incompleteness (life longings) is compatible with feelings of unequivocal joy and pleasure. Yet, there is emerging evidence that they contribute to other aspects of positive development, emphasizing personal growth, meaning, and the aligning of one's own and other's well-being. We suggest that future research should focus on the links of wisdom and life longings with multiple developmental outcomes and the possible interplay of both concepts in promoting positive development.


2021 ◽  
Author(s):  
Polona Caserman ◽  
Augusto Garcia-Agundez ◽  
Alvar Gámez Zerban ◽  
Stefan Göbel

AbstractCybersickness (CS) is a term used to refer to symptoms, such as nausea, headache, and dizziness that users experience during or after virtual reality immersion. Initially discovered in flight simulators, commercial virtual reality (VR) head-mounted displays (HMD) of the current generation also seem to cause CS, albeit in a different manner and severity. The goal of this work is to summarize recent literature on CS with modern HMDs, to determine the specificities and profile of immersive VR-caused CS, and to provide an outlook for future research areas. A systematic review was performed on the databases IEEE Xplore, PubMed, ACM, and Scopus from 2013 to 2019 and 49 publications were selected. A summarized text states how different VR HMDs impact CS, how the nature of movement in VR HMDs contributes to CS, and how we can use biosensors to detect CS. The results of the meta-analysis show that although current-generation VR HMDs cause significantly less CS ($$p<0.001$$ p < 0.001 ), some symptoms remain as intense. Further results show that the nature of movement and, in particular, sensory mismatch as well as perceived motion have been the leading cause of CS. We suggest an outlook on future research, including the use of galvanic skin response to evaluate CS in combination with the golden standard (Simulator Sickness Questionnaire, SSQ) as well as an update on the subjective evaluation scores of the SSQ.


2021 ◽  
Vol 29 (1) ◽  
pp. 66-77
Author(s):  
Erin Hurley ◽  
Timo Dietrich ◽  
Sharyn Rundle-Thiele

Co-design empowers people, giving them a voice in social marketing program design; however, approaches have mostly excluded expert knowledge. An abductive approach to co-design allows for inclusion of expert knowledge, providing theoretical guidance while simultaneously investigating user views and ideas extending understanding beyond known effective approaches. We use the seven-step co-design framework and outline how an abductive inference can be applied to co-design. Social cognitive theory constructs were integrated into the seven-step co-design process. The abductive approach to co-design was tested in two co-design sessions involving 40 participants. Findings demonstrate that theory can be successfully integrated into the seven-step co-design process through utilization of theory-mapped activity cards. This article provides guidance on how theory can be incorporated into ideation and insight generation. Limitations and future research recommendations are provided.


2021 ◽  
pp. 0272989X2199662
Author(s):  
Tammy C. Hoffmann ◽  
Mina Bakhit ◽  
Marie-Anne Durand ◽  
Lilisbeth Perestelo-Pérez ◽  
Catherine Saunders ◽  
...  

Background Patients and clinicians expect the information in patient decision aids to be based on the best available research evidence. The objectives of this International Patient Decision Aid Standards (IPDAS) review were to 1) check the currency of, and where needed, update evidence for the domain of “basing the information in decision aids on comprehensive, critically appraised, and up-to-date syntheses of the evidence”; 2) analyze the evidence characteristics of decision aids; and 3) propose updates to relevant IPDAS criteria. Methods We searched MEDLINE and PubMed to inform updates of this domain’s definitions, justifications, and components. We also searched 5 sources to identify all publicly available decision aids ( N = 471). Two assessors independently extracted each aid’s evidence characteristics. Results Minor updates to the definitions and theoretical justifications of this IPDAS domain are provided and changes to relevant IPDAS criteria proposed. Nearly all aids (97%) provided a year of creation/update, but most (81%) did not report an explicit update or expiration policy. No scientific references were cited in 33% of aids. Of the 314 that cited at least 1 reference, 39% cited at least 1 guideline, 44% cited at least 1 systematic review, and 23% cited at least 1 randomized trial. In 35%, it was unclear what statement in the aid the citations referred to. Only 14% reported any of the processes used to find and decide on evidence inclusion. Only 14% reported the evidence quality. Many emerging issues and future research areas were identified. Conclusions Although many emerging issues need to be addressed, this IPDAS domain is validated and criteria refined. High-quality patient decision aids should be based on comprehensive and up-to-date syntheses of critically appraised evidence.


2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.


2021 ◽  
Vol 13 (8) ◽  
pp. 4400
Author(s):  
Zhao Zhai ◽  
Ming Shan ◽  
Amos Darko ◽  
Albert P. C. Chan

Corruption has been identified as a major problem in construction projects. It can jeopardize the success of these projects. Consequently, corruption has garnered significant attention in the construction industry over the past two decades, and several studies on corruption in construction projects (CICP) have been conducted. Previous efforts to analyze and review this body of knowledge have been manual, qualitative and subjective, thus prone to bias and limited in the number of reviewed studies. There remains a lack of inclusive, quantitative, objective and computational analysis of global CICP research to inform future research, policy and practice. This study aims to address this lack by providing the first inclusive bibliometric study exploring the state-of-the-art of global CICP research. To this end, a quantitative and objective technique aided by CiteSpace was used to systematically and computationally analyze a large corpus of 542 studies retrieved from the Web of Science and published from 2000 to 2020. The findings revealed major and influential CICP research journals, persons, institutions, countries, references and areas of focus, as well as revealing how these interact with each other in research networks. This study contributes to the in-depth understanding of global research on CICP. By highlighting the principal research areas, gaps, emerging trends and directions, as well as patterns in CICP research, the findings could help researchers, practitioners and policy makers position their future CICP research and/or mitigation strategies.


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