Academic literature on the topic 'Significant uncertainties'
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Journal articles on the topic "Significant uncertainties"
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Constantino, Thomas, and Isabelle Baraffe. "Significant uncertainties from calibrating overshooting with eclipsing binary systems." Astronomy & Astrophysics 618 (October 2018): A177. http://dx.doi.org/10.1051/0004-6361/201833568.
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The precise measurement of the masses and radii of stars in eclipsing binary systems provides a window into uncertain processes in stellar evolution, especially mixing at convective boundaries. Recently, these data have been used to calibrate models of convective overshooting in the cores of main sequence stars. In this study we have used a small representative sample of eclipsing binary stars with 1.25 ≤ M/M⊙ < 4.2 to test how precisely this method can constrain the overshooting and whether the data support a universal stellar mass–overshooting relation. We do not recover the previously reported stellar mass dependence for the extent of overshooting and in each case we find there is a substantial amount of uncertainty, that is, the same binary pair can be matched by models with different amounts of overshooting. Models with a moderate overshooting parameter 0.013 ≤ fos ≤ 0.014 (using the scheme from Herwig et al. 1997, A&A, 324, L81) are consistent with all eight systems studied. Generally, a much larger range of f is suitable for individual systems. In the case of main sequence and early post-main sequence stars, large changes in the amount of overshooting have little effect on the radius and effective temperature, and therefore the method is of extremely limited utility.
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Pfannschmidt, Joachim. "Expanding the knowledge of oligometastatic disease—but uncertainties remain significant." Journal of Thoracic Disease 11, S15 (September 2019): S2008—S2011. http://dx.doi.org/10.21037/jtd.2019.06.39.
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Levine, Marc H., and Adrian P. Fitzsimons. "New AcSEC requirements for disclosure of certain significant risks and uncertainties." Journal of Corporate Accounting & Finance 6, no. 3 (1995): 109–20. http://dx.doi.org/10.1002/jcaf.3970060312.
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Wang, Y.-Y., H.-S. Lau, and Z.-S. Hua. "Three revenue-sharing variants: their significant performance differences under system-parameter uncertainties." Journal of the Operational Research Society 63, no. 12 (December 2012): 1752–64. http://dx.doi.org/10.1057/jors.2011.131.
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Skillman, Evan D. "Uncertainties in nebular helium abundances." Proceedings of the International Astronomical Union 5, S268 (November 2009): 113–18. http://dx.doi.org/10.1017/s1743921310003947.
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AbstractEfforts to determine the primordial helium abundance via observations of metal poor HII regions have been limited by significant uncertainties. Because of a degeneracy between the solutions for density and temperature, the precision of the helium abundance determinations is limited. Spectra from the literature are used to show the effects of new atomic data and to demonstrate the challenges of determining precise He abundances. Several suggestions are made for meeting these challenges.
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Gerber, Brian D., and William L. Kendall. "Adaptive management of animal populations with significant unknowns and uncertainties: a case study." Ecological Applications 28, no. 5 (June 1, 2018): 1325–41. http://dx.doi.org/10.1002/eap.1734.
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Yu, Z., C. S. Kochanek, B. M. Peterson, Y. Zu, W. N. Brandt, E. M. Cackett, M. M. Fausnaugh, and I. M. McHardy. "On reverberation mapping lag uncertainties." Monthly Notices of the Royal Astronomical Society 491, no. 4 (December 11, 2019): 6045–64. http://dx.doi.org/10.1093/mnras/stz3464.
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ABSTRACT We broadly explore the effects of systematic errors on reverberation mapping lag uncertainty estimates from javelin and the interpolated cross-correlation function (ICCF) method. We focus on simulated light curves from random realizations of the light curves of five intensively monitored AGNs. Both methods generally work well even in the presence of systematic errors, although javelin generally provides better error estimates. Poorly estimated light-curve uncertainties have less effect on the ICCF method because, unlike javelin , it does not explicitly assume Gaussian statistics. Neither method is sensitive to changes in the stochastic process driving the continuum or the transfer function relating the line light curve to the continuum. The only systematic error we considered that causes significant problems is if the line light curve is not a smoothed and shifted version of the continuum light curve but instead contains some additional sources of variability.
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Kainiemi, Laura, Sanni Eloneva, and Mika Järvinen. "An assessment of the uncertainties related to bioenergy applications." Management of Environmental Quality: An International Journal 25, no. 3 (April 8, 2014): 301–12. http://dx.doi.org/10.1108/meq-11-2013-0124.
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Purpose – The purpose of this paper is to identify the most significant uncertainties for bioenergy applications, in order to identify factors determining the success of introducing bioenergy into the current energy system. Design/methodology/approach – A framework is built for identifying the most significant uncertainties based on studies exploring the positive potentials as well as possible negative effects of bioenergy. The framework is applied to explore uncertainties of bioenergy-based transport fuels and heat and power generation through two real life case studies. Findings – The results indicate that the most significant uncertainties are environmental and economic. Bioenergy applications have potential to mitigate climate change, but also come with negative environmental effects. Case studies show that operations in developing nations contain higher political/institutional and social uncertainty than those in developed countries, due to weaker regulations and enforcement. Research limitations/implications – The paper is part of an on-going research project. Results will be verified with stakeholder interviews and analysis. Further institutional analysis of the country settings is necessary. Practical implications – The use of a feedstock with high environmental, social and institutional uncertainties will lower public acceptance. Acting in accordance to the law is not sufficient to ensure sustainability and additional, voluntary measures should be undertaken. Originality/value – The paper identifies the most significant uncertainties for bioenergy. Uncertainties from social acceptance and institutional settings are higher in developing countries and acceptability requires more than following regulations.
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Goudar, D. M., M. S. Hossain, Christopher E. Truman, Ed J. Kingston, and David John Smith. "Uncertainties in Triaxial Residual Stress Measurements." Materials Science Forum 681 (March 2011): 498–503. http://dx.doi.org/10.4028/www.scientific.net/msf.681.498.
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Residual stress measurement techniques using mechanical strain relaxation depend on a number of physical quantities and are therefore sensitive to errors associated with the measured data. The resulting stress uncertainties can easily become significant and compromise the usefulness of the results or lead to misinterpretation of the behaviour of the residual stress distributions. It is therefore essential to develop an error analysis procedure for the measurements undertaken. Error analysis procedures for the deep hole drilling (DHD) method are developed to consider triaxial residual stresses. A modified deep hole drilling method, called the incremental deep-hole drilling (iDHD), was applied to measure the near yield residual stress distributions in a cold water quenched aluminium 7010 alloy forged block. The experimental results are used to illustrate the errors.
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Nessim, M. A., H. P. Hong, and I. J. Jordaan. "Environmental Load Uncertainties for Offshore Structures." Journal of Offshore Mechanics and Arctic Engineering 117, no. 4 (November 1, 1995): 245–51. http://dx.doi.org/10.1115/1.2827230.
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A methodology for assessing the effect of different sources of uncertainty on the calculation of load effect on offshore structures is presented. A consistent classification of uncertainties was adopted and used as a basis to develop models to estimate the effect of different uncertainties on specified design loads. It is shown that distribution parameter uncertainties arising from limitations on the quantity of statistical data are not likely to have a significant effect on design loads. By contrast, model uncertainties can greatly increase the design loads, and the increase is sensitive to the probabilistic models used to describe model error. The methodology and results can be used by design engineers to take model uncertainties into account in estimating specified loads. They also form the basis for developing and calibrating a new information-sensitive code format.
Dissertations / Theses on the topic "Significant uncertainties"
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Johansson, Lukas, and Jennie Karlsson. "REVISORERS GRANSKNING AV GOING CONCERN UNDER KRIS : En studie om going concern under coronapandemin och finanskrisen." Thesis, Högskolan i Skövde, Institutionen för handel och företagande, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-20062.
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Bakgrund: Going concern är en av grundprinciperna inom redovisning, vilket innebär att företagen ska fortsätta sin verksamhet under en överskådlig framtid. Under kriser kan osäkerheter uppstå för företag, vilket gör att revisorernas granskning av ett företags förmåga till fortlevnad blir extra intressant att studera. I tidigare forskning har studier gjorts om hur coronapandemin generellt påverkat revisorernas granskning, medan den här studien undersöker hur revisorernas granskning av going concern har förändrats under coronapandemin och finanskrisen. Det finns ingen tidigare forskning angående skillnader och likheter mellan coronapandemin och finanskrisen med avseende till revisorns granskning av going concern, vilket är anledningen till att det undersöks. Problemformuleringar: Hur och varför har revisorernas granskning av förmågan till fortsatt drift (going concern) förändrats under coronapandemin och finanskrisen? Vilka skillnader eller likheter finns det mellan coronapandemin och finanskrisen angående revisorernas granskning av förmågan till fortsatt drift (going concern)? Syfte: Syftet med studien är att få en förståelse över hur revisorerna granskar förmågan till fortsatt drift (going concern) under coronapandemin och finanskrisen och varför revisorernas granskning förändras under dessa kriser. I studien kommer det institutionella trycket hjälpa till att skapa en förståelse för varför revisorernas granskning förändras under kriser. Studien kommer även undersöka utifrån revisorernas perspektiv om det finns några skillnader eller likheter i väsentliga osäkerheter i företagen, ändamålsenliga revisionsbevis samt djupgående granskning mellan finanskrisen och coronapandemin. Resultat och slutsats: Studiens slutsatser är att revisorernas granskning av going concern har förändrats under coronapandemin och finanskrisen. Nya lagar och regler har tillkommit som revisorer i sin granskning behöver förhålla sig till, vilket studien indikerar att dessa förändringar kan förklaras av ett förändrat institutionellt tryck. Coronapandemin och finanskrisen har bidragit till mer djupgående granskning och revisorerna måste säkerställa att de inhämtade revisionsbevisen har en hög kvalitet. Studien har även identifierat att det finns skillnader och likheter angående revisorernas granskning av going concern mellan coronapandemin och finanskrisen, vilket härrör från väsentliga osäkerheter, ändamålsenliga revisionsbevis och djupgående granskning.Background: Going concern is one of the basic principles in accounting, which means that companies must continue their operations in the foreseeable future. In previous research studies have been done on how the corona pandemic generally has affected the auditors review, while this study examines what the auditors' review of going concern has shown during the corona pandemic. There are already studies on the financial crisis linked to going concern, but there is no previous research regarding differences and similarities between the corona pandemic and the financial crisis. Research questions: How and why have the auditors' review of the ability to continue operating (going concern) changed during the corona pandemic and the financial crisis?What are the differences and similarities between the financial crisis and the corona pandemic regarding the auditors review of going concern? Purpose of study: The purpose of the study is to gain an understanding of how the auditors examine the ability to continue operations (going concern) during the corona pandemic and the financial crisis and why the auditors examine changes during these crises. In the study, the institutional pressure will help to create an understanding of why auditors examine change during crises. The study will also examine from the auditors' perspective whether there are any differences or similarities in significant uncertainties, appropriate audit evidence and an in-depth review between the financial crisis and the corona pandemic. Results and conclusion: The study's conclusions are that the auditors' review of the going concern has changed during the corona pandemic and the financial crisis, which contributes to the review not looking the same during a crisis. The corona pandemic and the financial crisis has led to the introduction of new laws and regulations, which auditors must follow and can be explained by institutional pressure. This has contributed to a more in-depth audit and also to the fact that the auditors must ensure that the audited evidence obtained is of a high quality. The study has identified that there are differences and similarities regarding the auditors' review of the going concern between the corona pandemic and the financial crisis, which stems from significant uncertainties, appropriate audit evidence and in-depth review.
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Pelletier, Patrice M. "Analysis of uncertainties in river discharge and the investigation of their relative significance using multiobjective analysis techniques." 1990. http://hdl.handle.net/1993/17205.
Full textBooks on the topic "Significant uncertainties"
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American Institute of Certified Public Accountants. Task Force on Risks and Uncertainties. Disclosure of certain significant risks and uncertainties and financial flexibility: Exposure draft [of] proposed statement of position, March 31, 1993. New York, N.Y: AICPA, 1993.
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Office, General Accounting. Strategic Defense Initiative: Changing design and technological uncertainties create significant risk : report to the Chairman, Legislation and National Security Subcommittee, Committee on Government Operations, House of Representatives. Washington, D.C: The Office, 1992.
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Thrift resolutions: FSLIC 1988 and 1989 assistance agreement costs subject to significant uncertainties : report to the Congress. Washington, D.C: The Office, 1991.
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Freeland, Steven. International Law and the Exploration and Use of Outer Space. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780198795896.003.0005.
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The 1957 launch of Sputnik I challenged humankind’s perceptions of what was possible in space, and necessitated the development of a legal framework for the exploration and use of outer space. However, these rules emerged at a time when the development of space-related technology was principally directed towards military objectives. As the possibility of a military confrontation in space increases, uncertainty coalesces with other risks, particularly with respect to the dangers posed by space debris, revealing lacunae in the law, the further evolution of which has largely stalled due to geopolitical factors. Emerging ‘soft’ law principles are neither entirely clear nor sufficiently comprehensive to meet the increasing complexity associated with attempting to regulate outer space. This chapter assesses the uncertainties arising from the existing international legal framework and their correlation to significant risks pertaining to the exploration and use of outer space.
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Tallacchini, Mariachiara. Medical Technologies and EU Law: The Evolution of Regulatory Approaches and Governance. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780198807216.003.0002.
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The regulatory evolution of medical technologies in the EU offers a unique perspective with regard to highlighting significant elements of both European science policy and the development of European institutions, especially with regard to the passage from their (primarily) economic to their political phases. Since the early 1990s, while establishing a market for biotechnology, the European Communities have been developing some policy-related visions of technoscience and its potential risks, while at the same time framing the concept of European citizenship through European values and rights. The emerging and re-emerging medical technology of xenotransplantation, namely the clinical use of cells, tissues, and organs between species, while having evolved from its primary focus on organs to so-called advanced therapies (cell therapy, gene therapy, and tissue-engineered products), also provided an opportunity to test and implement different science policy models in dealing with risks and uncertainties in the European knowledge-based and innovation-oriented society.
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Tutino, Stefania. Uncertainty in Post-Reformation Catholicism. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190694098.001.0001.
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This book provides a historical account of the development and implications of early modern probabilism. First elaborated in the sixteenth century, probabilism represented a significant and controversial novelty in Catholic moral theology. Against a deep-seated tradition defending the strict application of moral rules, probabilist theologians maintained that in situations of uncertainty, the agent can legitimately follow any course of action supported by a probable opinion, no matter how disputable. By the second half of the seventeenth century, and thanks in part to Pascal’s influential antiprobabilist stances, probabilism had become inextricably linked to the Society of Jesus and to a lax and excessively forgiving moral system. To this day, most historians either ignore probabilism, or they associate it with moral duplicity and intellectual and cultural decadence. By contrast, this book argues that probabilism was instrumental for addressing the challenges created by a geographically and intellectually expanding world. Early modern probabilist theologians saw that these challenges provoked an exponential growth of uncertainties, doubts, and dilemmas of conscience, and they realized that traditional theology was not equipped to deal with them. Therefore, they used probabilism to integrate changes and novelties within the post-Reformation Catholic theological and intellectual system. Seen in this light, probabilism represented the result of their attempts to appreciate, come to terms with, and manage uncertainty. Uncertainty continues to play a central role even today. Thus, learning how early modern probabilists engaged with uncertainty might be useful for us as we try to cope with our own moral and epistemological doubts.
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Grare, Frédéric. India Turns East. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190859336.001.0001.
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India Turns East tells the story of India’s long and difficult journey to reclaim its status in a rapidly changed environment increasingly shaped by the US-China rivalry and the uncertainties of US commitment to Asia’s security. The so-called Look East Policy initially aimed at reconnecting India with Asia’s economic globalization. As China becomes more assertive, Look East has rapidly evolved into a comprehensive strategy with political and military dimensions which, together with favourable circumstances, have gradually allowed for a closer relationship with the United States. But the book argues that despite this rapprochement, the congruence of Indian and US objectives regarding China is not absolute. The two countries share similar concerns, but differ about the role China should play in the emerging regional architecture. Moreover, though bilateral US policies are usually perceived positively in New Delhi, paradoxically, the multilateral dimension of the US Rebalance to Asia policy sometimes pushes New Delhi closer to Beijing’s positions than to Washington’s. The asymmetry of power between the United States and India and their geographic separation make the persistence of significant divergences inevitable. The challenge for India is to reinvent the concept of strategic autonomy — defined as a position allowing India to leverage US capacities while avoiding being drawn into a zero-sum game between the US and China — but it will ultimately be able to do so only if it does make itself more attractive. Economic reforms are a key to India relationships with both the US and China.
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Tutino, Stefania. Conclusion. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190694098.003.0012.
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This chapter explores the reasons why the doctrine of probabilism is no longer prominent in our intellectual and scholarly horizon. These reasons include the advent of Alphonsus Maria de’ Liguori’s equiprobabilism; the progressive loss of political, social, and cultural capital of the nineteenth-century Roman Curia; and the triumph of Cartesian epistemology in the modern secularized world. This chapter also argues for the necessity to recover the centrality of probabilism, both because probabilism and moral theology were a crucial component of the cultural, political, and religious history of early modern Europe, and because learning how early modern probabilists grappled with uncertainty can be distinctively useful for us today. Even though we are the most informed generation on Earth, we seem to be losing the ability to distinguish facts and truths from opinions. Thus, appreciating the historical significance of probabilism can help us to navigate our current epistemological and moral uncertainties.
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Brunner, Ronald D., and Amanda H. Lynch. Adaptive Governance. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.601.
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Adaptive governance is defined by a focus on decentralized decision-making structures and procedurally rational policy, supported by intensive natural and social science. Decentralized decision-making structures allow a large, complex problem like global climate change to be factored into many smaller problems, each more tractable for policy and scientific purposes. Many smaller problems can be addressed separately and concurrently by smaller communities. Procedurally rational policy in each community is an adaptation to profound uncertainties, inherent in complex systems and cognitive constraints, that limit predictability. Hence planning to meet projected targets and timetables is secondary to continuing appraisal of incremental steps toward long-term goals: What has and hasn’t worked compared to a historical baseline, and why? Each step in such trial-and-error processes depends on politics to balance, if not integrate, the interests of multiple participants to advance their common interest—the point of governance in a free society. Intensive science recognizes that each community is unique because the interests, interactions, and environmental responses of its participants are multiple and coevolve. Hence, inquiry focuses on case studies of particular contexts considered comprehensively and in some detail.Varieties of adaptive governance emerged in response to the limitations of scientific management, the dominant pattern of governance in the 20th century. In scientific management, central authorities sought technically rational policies supported by predictive science to rise above politics and thereby realize policy goals more efficiently from the top down. This approach was manifest in the framing of climate change as an “irreducibly global” problem in the years around 1990. The Intergovernmental Panel on Climate Change (IPCC) was established to assess science for the Conference of the Parties (COP) to the U.N. Framework Convention on Climate Change (UNFCCC). The parties negotiated the Kyoto Protocol that attempted to prescribe legally binding targets and timetables for national reductions in greenhouse gas emissions. But progress under the protocol fell far short of realizing the ultimate objective in Article 1 of the UNFCCC, “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference in the climate system.” As concentrations continued to increase, the COP recognized the limitations of this approach in Copenhagen in 2009 and authorized nationally determined contributions to greenhouse gas reductions in the Paris Agreement in 2015.Adaptive governance is a promising but underutilized approach to advancing common interests in response to climate impacts. The interests affected by climate, and their relative priorities, differ from one community to the next, but typically they include protecting life and limb, property and prosperity, other human artifacts, and ecosystem services, while minimizing costs. Adaptive governance is promising because some communities have made significant progress in reducing their losses and vulnerability to climate impacts in the course of advancing their common interests. In doing so, they provide field-tested models for similar communities to consider. Policies that have worked anywhere in a network tend to be diffused for possible adaptation elsewhere in that network. Policies that have worked consistently intensify and justify collective action from the bottom up to reallocate supporting resources from the top down. Researchers can help realize the potential of adaptive governance on larger scales by recognizing it as a complementary approach in climate policy—not a substitute for scientific management, the historical baseline.
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Lee, Jeong-Dong, Keun Lee, Dirk Meissner, Slavo Radosevic, and Nicholas Vonortas, eds. The Challenges of Technology and Economic Catch-up in Emerging Economies. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780192896049.001.0001.
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This book synthesizes and interprets existing knowledge on technology upgrading failures as well as lessons from successes and failures in order to better understand the challenges of technology upgrading in emerging economies. The objective is to bring together in one volume diverse evidence regarding three major dimensions of technology upgrading: paths of technology upgrading, structural changes in the nature of technology upgrading, and the issues of technology transfer and technology upgrading. The knowledge of these three dimensions is being synthesized at the firm, sector, and macro levels across different countries and world macro-regions. Compared to the old and new challenges and uncertainties facing emerging economies, our understanding of the technology upgrading is sparse, unsystematic, and scattered. While our understanding of these issues from the 1980s and 1990s is relatively more systematized, the changes that took place during the globalization and proliferation of GVCs, the effects of the post-2008 events, and the effects of the current COVID-19 and geopolitical struggles on technology upgrading have not been explored and compared synthetically. Moreover, the recent growth slowdown in many emerging economies, often known as a middle-income trap, has reinforced the importance of understanding the technology upgrading challenges of catching-up economies. We believe that the time is ripe for “taking stock of the area” in order to systematize and evaluate the existing knowledge on processes of technology upgrading of emerging economies at the firm, sector, and international levels and to make further inroads in research on this issue. This volume aims to significantly contribute towards this end.
Book chapters on the topic "Significant uncertainties"
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Yüksel, Berkay, and Mehmet Okan Görtan. "Dealing with Uncertainties in Fatigue Strength Using Deep Rolling." In Lecture Notes in Mechanical Engineering, 93–103. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77256-7_9.
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AbstractMechanical properties inherently possess uncertainties. Among these properties, fatigue behavior data generally shows significant scatter which introduces a challenge in the safe design of dynamically loaded components. These uncertainties in fatigue behavior are mainly results of factors related to surface state including: Roughness, tensile residual stresses, scratches and notches at surface. Therefore, controlling these parameters allows one to increase fatigue strength and reduce scatter and uncertainties in fatigue behavior. Mechanical surface treatments are applied on parts to increase fatigue strength via introducing compressive residual stresses and work-hardening at surface. Two of the most common among these treatments are shot peening and deep rolling. Shot peening has found many applications in industry because of its flexibility. However, it introduces irregularities at the surface and may increase roughness which causes uncertainties in the fatigue behavior data; especially for low-medium strength materials. Unlike shot peening, deep rolling reduces surface roughness. Therefore, it has the capability to reduce uncertainty in the fatigue behavior. To this date, rolling direction of deep rolling was selected as tangential direction to turning direction for axisymmetric parts. Nonetheless, the authors believe that the rolling direction has an apparent effect on the fatigue behavior. In this study, longitudinal direction was also applied for deep rolling operation and the results of these two direction applications on the EN-AW-6082 aluminum alloy were investigated. It was shown that, longitudinal rolling had yielded less scatter and uncertainty in the fatigue behavior than the tangential rolling together with the higher fatigue strength.
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Kinne, Marko, Ronald Schneider, and Sebastian Thöns. "Reconstructing Stress Resultants in Wind Turbine Towers Based on Strain Measurements." In Lecture Notes in Mechanical Engineering, 224–35. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77256-7_18.
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AbstractSupport structures of offshore wind turbines are subject to cyclic stresses generated by different time-variant random loadings such as wind, waves, and currents in combination with the excitation by the rotor. In the design phase, the cyclic demand on wind turbine support structure is calculated and forecasted with semi or fully probabilistic engineering models. In some cases, additional cyclic stresses may be induced by construction deviations, unbalanced rotor masses and structural dynamic phenomena such as, for example, the Sommerfeld effect. Both, the significant uncertainties in the design and a validation of absence of unforeseen adverse dynamic phenomena necessitate the employment of measurement systems on the support structures. The quality of the measurements of the cyclic demand on the support structures depends on (a) the precision of the measurement system consisting of sensors, amplifier and data normalization and (b) algorithms for analyzing and converting data to structural health information. This paper presents the probabilistic modelling and analysis of uncertainties in strain measurements performed for the purposes of reconstructing stress resultants in wind turbine towers. It is shown how the uncertainties in the strain measurements affect the uncertainty in the individual components of the reconstructed forces and moments. The analysis identifies the components of the vector of stress resultants that can be reconstructed with sufficient precision.
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Alliagbor, Rasheedat, David Olufemi Awolala, and Igbekele Amos Ajibefun. "Smallholders Use of Weather Information as Smart Adaptation Strategy in the Savannah Area of Ondo State, Nigeria." In African Handbook of Climate Change Adaptation, 1601–11. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_126.
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AbstractWeather information is needed for smart decisions because uncertainties in weather phenomena are beyond capacity of smallholders for autonomous responses. The study analyzed determinants of farmers’ use of weather information as smart adaptation strategy. Arable crop farmers were sampled in the derived savannah agro-ecology area of Ondo State, Nigeria. Heckman probit model estimates show that gender and agricultural extension services were significant positive drivers of farmers’ access to weather information. Should weather information becomes an alternative adaptation strategy, access to credit was found as the major driver of farmers’ propensity to use weather information before taking climate smart agricultural decisions. Further results reveal that increasing knowledge of onset date, large farm size, and access to agricultural extension services significantly reduced farmers’ propensity to use improved weather information for smart decisions in the dry savannah area.
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Spel, Jip, Sebastian Junges, and Joost-Pieter Katoen. "Finding Provably Optimal Markov Chains." In Tools and Algorithms for the Construction and Analysis of Systems, 173–90. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-72016-2_10.
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AbstractParametric Markov chains (pMCs) are Markov chains with symbolic (aka: parametric) transition probabilities. They are a convenient operational model to treat robustness against uncertainties. A typical objective is to find the parameter values that maximize the reachability of some target states. In this paper, we consider automatically proving robustness, that is, an $$\varepsilon $$ ε -close upper bound on the maximal reachability probability. The result of our procedure actually provides an almost-optimal parameter valuation along with this upper bound.We propose to tackle these ETR-hard problems by a tight combination of two significantly different techniques: monotonicity checking and parameter lifting. The former builds a partial order on states to check whether a pMC is (local or global) monotonic in a certain parameter, whereas parameter lifting is an abstraction technique based on the iterative evaluation of pMCs without parameter dependencies. We explain our novel algorithmic approach and experimentally show that we significantly improve the time to determine almost-optimal synthesis.
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Muller, Mike. "Managing Current Climate Variability Can Ensure Water Security Under Climate Change." In African Handbook of Climate Change Adaptation, 1–27. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-42091-8_243-1.
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AbstractWater resources will be significantly impacted upon by climate change, and these impacts will be transmitted to the many sectors and services dependent on them. The nature, extent, and timing of these impacts remain uncertain, but the long lifetime of water infrastructures requires that their planning, development, and operations should be resilient to climate changes. An effective approach is to focus on the management of current climate variability as it relates to water, which strengthens the ability of communities and countries to foresee, manage, and adapt to the impacts of longer-term climate change on water-related activities. This approach is illustrated by cases from Southern and Eastern Africa.Current “stationary” stochastic methods of hydrological analysis can still be used under assumptions of a “dynamic stationarity” although more regular updating of hydrological data will be required. Methodologies to evaluate economic dimensions of risk reduction introduce additional uncertainties but may help decision-makers to understand the risks and opportunities. Diversification of sources and sequencing of resource development pathways are helpful strategies to adapt to climate change but must ensure that risks affecting different sources are not correlated. Attention must also be given to demand-side interventions in order to reconcile supply and demand, and these perspectives must be shared with social, economic, and political actors to ensure that strategies are communicated, understood, and supported by the wider community.
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Muller, Mike. "Managing Current Climate Variability Can Ensure Water Security Under Climate Change." In African Handbook of Climate Change Adaptation, 2311–37. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_243.
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AbstractWater resources will be significantly impacted upon by climate change, and these impacts will be transmitted to the many sectors and services dependent on them. The nature, extent, and timing of these impacts remain uncertain, but the long lifetime of water infrastructures requires that their planning, development, and operations should be resilient to climate changes. An effective approach is to focus on the management of current climate variability as it relates to water, which strengthens the ability of communities and countries to foresee, manage, and adapt to the impacts of longer-term climate change on water-related activities. This approach is illustrated by cases from Southern and Eastern Africa.Current “stationary” stochastic methods of hydrological analysis can still be used under assumptions of a “dynamic stationarity” although more regular updating of hydrological data will be required. Methodologies to evaluate economic dimensions of risk reduction introduce additional uncertainties but may help decision-makers to understand the risks and opportunities. Diversification of sources and sequencing of resource development pathways are helpful strategies to adapt to climate change but must ensure that risks affecting different sources are not correlated. Attention must also be given to demand-side interventions in order to reconcile supply and demand, and these perspectives must be shared with social, economic, and political actors to ensure that strategies are communicated, understood, and supported by the wider community.
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MILROY, ALASTAIR M. "Law Enforcement Agencies which Respond to Nationally Significant Crime." In Dealing with Uncertainties in Policing Serious Crime. ANU Press, 2010. http://dx.doi.org/10.22459/dupsc.05.2010.13.
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Kampourakis, Kostas, and Kevin McCain. "Uncertainties in Vaccination." In Uncertainty, 93–106. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190871666.003.0007.
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Whereas vaccines have helped save millions of lives over the past several decades, today there is a significant anti-vaccination (anti-vaxx) movement, especially in the United States, that questions their safety. The problem is that these anti-vaxx arguments focus on rare cases of side effects or—even worse—on unfounded connections between the administration of vaccines and particular conditions such as autism. Such reactions make people overlook the fact that several diseases that in the past killed millions of people have been completely or almost completely eradicated thanks to vaccines. Even though vaccine side effects are a real possibility, one has to weigh the risk of facing those (which is very low and arise in relatively rare cases) against the hundreds or thousands of children who, thanks to the vaccine, will avoid hospitalization or even death. Uncertainties always exist, and we cannot be absolutely certain about the efficacy and safety of any vaccine. But for many of them, there is solid evidence that the problems are rare, and certainly the affected individuals are a lot fewer than those who might suffer and even die from the disease.
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Selman Çolak, Mehmet, İbrahim Ethem Güney, and Yavuz Selim Hacıhasanoğlu. "The Relationship between Economic Uncertainty and Firms’ Balance Sheet Strength." In Banking and Finance. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.91860.
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This chapter aims to elaborate on the relationship between economic uncertainty and balance sheet strength of nonfinancial firms in Turkish economy. In order to effectively measure the balance sheet strength, we make use of a multivariate indicator, namely, the Multivariate Firm Assessment Score (MFA Score), which is a composite index to gauge the credit risk of nonfinancial firms quoted in Borsa İstanbul. MFA scores are compared with some uncertainty indicators for the period of 2005–2019. Our results suggest that when the uncertainties in global or Turkish economy are high, we observe a significant causal relationship from uncertainty indicators to firms’ balance sheet strength. More specifically, economic uncertainties negatively affect firms’ balance sheet performance in such an environment. Moreover, different types of uncertainties such as trade policy uncertainty and consumer perceptions about the economy are found to have differential impacts on exporter and non-exporter firms.
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Ritchie, Bob, and Clare Brindley. "Risk Management in the Digital Economy." In Encyclopedia of Information Science and Technology, First Edition, 2431–37. IGI Global, 2005. http://dx.doi.org/10.4018/978-1-59140-553-5.ch430.
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The digital economy has been generated by radical changes to every aspect of business and commerce in the last two decades. These changes are far more significant than the developments in Information and Communication Technologies (ICTs) that have largely facilitated the digital economy itself. Every business sector has witnessed changes in the competitive structure of the marketplace, consumer preferences, buying habits, marketing and promotional strategies, production operations, internal administration systems, supply chain arrangements, and the opening up of the global economy. Managers would concede that the uncertainties and risks in running their businesses, as a result of such changes, are not only much greater than previously but increasing. However, the digital economy is a two-edged sword in the sense that the ICTs generating the additional uncertainties and risks also provide the means to enable decision makers to manage them more effectively. The key to survival in the digital economy rests with the abilities of the managers to utilize ICTs effectively to manage uncertainties and risks.
Conference papers on the topic "Significant uncertainties"
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Peng, Cheong Yaw, and Ritu Gupta. "Experimental Design in Deterministic Modelling: Assessing Significant Uncertainties." In SPE Asia Pacific Oil and Gas Conference and Exhibition. Society of Petroleum Engineers, 2003. http://dx.doi.org/10.2118/80537-ms.
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Schnetter, Philipp, and Thomas Kruger. "Compensation of significant parametric uncertainties using sliding mode online learning." In 2013 IEEE Aerospace Conference. IEEE, 2013. http://dx.doi.org/10.1109/aero.2013.6497360.
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Wang, Lijun, Qing Li, Chaonan Tong, Yixin Yin, Zhiqiang Gao, Qinling Zheng, and Weicun Zhang. "On control design and tuning for first order plus time delay plants with significant uncertainties." In 2015 American Control Conference (ACC). IEEE, 2015. http://dx.doi.org/10.1109/acc.2015.7172163.
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Sridharan, S., A. A. Rodriguez, J. J. Dickeson, and D. Soloway. "Constraint enforcement and robust tube-based control for scramjet-powered hypersonic vehicles with significant uncertainties." In 2012 American Control Conference - ACC 2012. IEEE, 2012. http://dx.doi.org/10.1109/acc.2012.6315659.
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Uygur, Ercan. "Uncertainties, Protectionism and Slowdown in Global Trade." In International Conference on Eurasian Economies. Eurasian Economists Association, 2018. http://dx.doi.org/10.36880/c10.02195.
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The United States announced plans to impose tariffs and quotas on her imports of certain commodities, notably iron, steel and aluminum, and on imports from certain countries, including those from China, in early 2018. These and counter announcements has been considered as the start of global trade wars.
Even before that, there has been a significant slowdown in the growth of world trade in recent years. In the three decades before 2011, annual world trade recorded a growth of about 6%. This was twice as high as world GDP growth, implying an income (GDP) elasticity of trade at around 2. Between 2011 – 2016, the income elasticity of trade has fallen to below 1, on average.
While the recent poor performance of global trade has been attributed to these structural and cyclical factors, this paper argues that the rise in both price uncertainty, demand uncertainty and policy uncertainty have and will have a significant effect on trade growth. Price uncertainty is reflected in fluctuations in real exchange rates, commodity prices and manufacturing prices. Demand uncertainty, on the other hand, is reflected by growth variability in time and among countries. Policy uncertainty can be traced in protectionist measures.
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Kurz, Rainer, and Klaus Brun. "On Test Uncertainties in Field Performance Tests." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42035.
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Field testing of gas turbine or electric motor driven compressor packages requires the accurate determination of efficiency, capacity, head, or power consumption in sometimes less than ideal working environments. Nonetheless, field test results have significant implication for the compressor and gas turbine manufacturers and their customers. Economic considerations demand that the performance and efficiency of an installation are verified to assure the return on investment for the project. Thus, for the compressor and gas turbine manufacturers, as well as for the end-user, an accurate determination of the field performance is of vital interest. This paper discusses a method to determine the measurement uncertainty and, thus, the accuracy, of test results under the typical constraints of a site performance test, for compressors capable of variable speed operation. Namely, a method is presented which can be employed to verify the validity of field test performance results. Results are compared with actual field test results, using redundant methods. Typical field test measurement uncertainties are presented for different sets of instrumentation. The effect of different equations of state on the calculated performance is also discussed. Test parameters that correlate to the most significant influence on the performance uncertainties are identified and suggestions are provided on how to minimize their measurement errors. Results show that compressor efficiency uncertainties can be unacceptably high when some basic rules for accurate testing are violated. However, by following some simple measurement rules and maintaining commonality of the gas equations of state, the overall compressor package performance measurement uncertainty can be limited and meaningful results can be achieved.
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Luo, X., G. V. Srinivasan, and W. K. Tredway. "Reliability Prediction of Monolithic Structural Ceramics With Uncertainties." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27935.
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Reliability prediction of monolithic structural ceramics involves stress analysis through Finite Element Analysis (FEA) and a probability of failure prediction code such as CARES that considers the strength of ceramics as a statistical (Weibull) distribution. Though the strength is considered as a statistical distribution, stress in a given volume or surface element is discrete in current practice. However, uncertainties in FEA input such as material properties or boundary conditions make the predicted stress uncertain, thereby resulting in predicted reliability being uncertain as well. A probabilistic framework has been developed for reliability prediction to estimate component reliability by treating the uncertainties in loading, boundary conditions, and material properties as random variables. The framework consists of an automated, closed loop process integrating algorithms for assessing failure probability due to general randomness. Efficient and accurate computational methods for reliability analysis have been implemented in the framework for significant savings in computation time. The methodology is demonstrated on a gas turbine component. The analysis shows that reliability is compromised significantly by a design based on mean values of the random parameters, while an overly conservative design based on a worst case scenario will result in rejection of too many components at unnecessarily high proof test loads. This method ultimately leads to the determination of an optimum proof test level to assure component reliability amidst several sources of uncertainties in reliability prediction.
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Niffenegger, M., O. Costa Garrido, D. F. Mora, G. Qian, R. Mukin, M. Sharabi, N. Lafferty, and B. Niceno. "Uncertainties in Pressurized Thermal Shock Analyses." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-94076.
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Abstract Integrity assessment of reactor pressure vessels (RPVs) can be performed either by deterministic fracture mechanics (DFM) or/and by probabilistic fracture mechanics (PFM) analyses. In European countries and Switzerland, only DFM analyses are required. However, in order to establish the probabilistic approach in Switzerland, the advantages and shortcomings of the PFM are investigated in the frame of a national research project. Both, the results from DFM and PFM depend strongly on the previous calculated thermal-hydraulic boundary conditions. Therefore, complete integrity analyses involving several integrated numerical codes and methods were performed for a reference pressurized water reactor (PWR) RPV subjected to pressurized thermal shock (PTS) loads. System analyses were performed with the numerical codes RELAP5 and TRACE, whereas for structural and fracture mechanics calculations, the FAVOR and ABAQUS codes were applied. Additional computational fluid dynamics analyses were carried out with ANSYS/FLUENT, and the plume cooling effect was alternatively considered with GRS-MIX. The results from the different analyses tools are compared, to judge the expected overall uncertainty and reliability of PTS safety assessments. It is shown that the scatter band of the stress intensities for a fixed crack configuration is rather significant, meaning that corresponding safety margins should be foreseen. The conditional probabilities of crack initiation and RPV failure might also differ, depending on the considered random parameters and applied rules.
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Vanem, Erik, Arne Bang Huseby, and Bent Natvig. "A Bayesian-Hierarchical Space-Time Model for Significant Wave Height Data." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49716.
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Bad weather and rough seas contribute significantly to the risk to maritime transportation. This stresses the importance of taking severe sea state conditions adequately into account, with due treatment of the uncertainties involved, in ship design and operation. Hence, there is a need for appropriate stochastic models describing the variability of sea states. This paper presents a Bayesian hierarchical space-time stochastic model for significant wave height. The model has been fitted by data for an area in the North Atlantic ocean and aims at describing the temporal and spatial variability of significant wave height in this area. It could also serve as foundation for further extensions used for long-term prediction of significant wave height and future return periods of extreme significant wave heights. The model will be outlined in this paper, and the results will be discussed. Furthermore, a discussion of possible model extensions will be presented.
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Vanem, Erik. "A Stochastic Model for Long-Term Trends in Significant Wave Height With a CO2 Regression Component." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83012.
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Bad weather and rough seas continue to be a major cause for ship losses and is thus a significant contributor to the risk to maritime transportation. This stresses the importance of taking severe sea state conditions adequately into account, with due treatment of the uncertainties involved, in ship design and operation. Hence, there is a need for appropriate stochastic models describing the variability of sea states. These should also incorporate realistic projections of future return levels of extreme sea states, taking into account long-term trends related to climate change and inherent uncertainties. The stochastic model presented in this paper allows for modelling of complex dependence structures in space and time and incorporation of physical features and prior knowledge, yet at the same time remains intuitive and easily interpreted. A regression component with CO2 as an explanatory variable has been introduced in order to extract and project long-term trends in the data. The model has been fitted by significant wave height data for an area in the North Atlantic ocean. The different components of the model will be outlined in the paper, and the results will be discussed.
Reports on the topic "Significant uncertainties"
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Kim, Changmo, Ghazan Khan, Brent Nguyen, and Emily L. Hoang. Development of a Statistical Model to Predict Materials’ Unit Prices for Future Maintenance and Rehabilitation in Highway Life Cycle Cost Analysis. Mineta Transportation Institute, December 2020. http://dx.doi.org/10.31979/mti.2020.1806.
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The main objectives of this study are to investigate the trends in primary pavement materials’ unit price over time and to develop statistical models and guidelines for using predictive unit prices of pavement materials instead of uniform unit prices in life cycle cost analysis (LCCA) for future maintenance and rehabilitation (M&R) projects. Various socio-economic data were collected for the past 20 years (1997–2018) in California, including oil price, population, government expenditure in transportation, vehicle registration, and other key variables, in order to identify factors affecting pavement materials’ unit price. Additionally, the unit price records of the popular pavement materials were categorized by project size (small, medium, large, and extra-large). The critical variables were chosen after identifying their correlations, and the future values of each variable were predicted through time-series analysis. Multiple regression models using selected socio-economic variables were developed to predict the future values of pavement materials’ unit price. A case study was used to compare the results between the uniform unit prices in the current LCCA procedures and the unit prices predicted in this study. In LCCA, long-term prediction involves uncertainties due to unexpected economic trends and industrial demand and supply conditions. Economic recessions and a global pandemic are examples of unexpected events which can have a significant influence on variations in material unit prices and project costs. Nevertheless, the data-driven scientific approach as described in this research reduces risk caused by such uncertainties and enables reasonable predictions for the future. The statistical models developed to predict the future unit prices of the pavement materials through this research can be implemented to enhance the current LCCA procedure and predict more realistic unit prices and project costs for the future M&R activities, thus promoting the most cost-effective alternative in LCCA.
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Muelaner, Jody Emlyn. Unsettled Issues in Electrical Demand for Automotive Electrification Pathways. SAE International, January 2021. http://dx.doi.org/10.4271/epr2021004.
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With the current state of automotive electrification, predicting which electrification pathway is likely to be the most economical over a 10- to 30-year outlook is wrought with uncertainty. The development of a range of technologies should continue, including statically charged battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs), plug-in hybrid electric vehicles (PHEVs), and EVs designed for a combination of plug-in and electric road system (ERS) supply. The most significant uncertainties are for the costs related to hydrogen supply, electrical supply, and battery life. This greatly is dependent on electrolyzers, fuel-cell costs, life spans and efficiencies, distribution and storage, and the price of renewable electricity. Green hydrogen will also be required as an industrial feedstock for difficult-to-decarbonize areas such as aviation and steel production, and for seasonal energy buffering in the grid. For ERSs, it is critical to understand how battery life will be affected by frequent cycling and the extent to which battery technology from hybrid vehicles can be applied. Unsettled Issues in Electrical Demand for Automotive Electrification Pathways dives into the most critical issues the mobility industry is facing.
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Bidier, S., U. Khristenko, R. Tosi, R. Rossi, and C. Soriano. D7.3 Report on UQ results and overall user experience. Scipedia, 2021. http://dx.doi.org/10.23967/exaqute.2021.9.002.
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This deliverable report focuses on the main Uncertainty Quanti cation (UQ) results obtained within the EXAscale Quanti cation of Uncertainties for Technology and Science Simulation (ExaQUte) project. Details on the turbulent wind inlet generator, that enables the supply of random, yet steady, wind velocity boundary conditions during run-time, are given in section 2. This enables the developed UQ workflow, whose results are presented on the basis of the Commonwealth Advisory Aeronautical Council (CAARC) as described in Deliverable 7.1. Finally, the completed UQ workflow and the results are evaluated from an application-driven wind engineering point of view. Thereby, the significance of the developed methods and the obtained results are discussed and their applicability in practical wind-engineering applications is tested through a complete test-run of the UQ workflow.