Journal articles: 'Uncertainty and fluctuations'

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Bloom, N. "Fluctuations in uncertainty." Voprosy Ekonomiki, no. 4 (April 20, 2016): 30–55. http://dx.doi.org/10.32609/0042-8736-2016-4-30-55.

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In this essay, the author addresses four questions about uncertainty. First, what are some facts and patterns about economic uncertainty? Both macro and micro uncertainty appear to rise sharply in recessions and fall in booms. Uncertainty also varies heavily across countries - developing countries appear to have about one-third more macro uncertainty than developed countries. Second, why does uncertainty vary during business cycles? Third, do fluctuations in uncertainty affect behavior? Fourth, has higher uncertainty worsened the Great Recession and slowed the recovery? Much of this discussion is based on research on uncertainty from the last five years, reflecting the recent growth of the literature.

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Bloom, Nicholas. "Fluctuations in Uncertainty." Journal of Economic Perspectives 28, no. 2 (May 1, 2014): 153–76. http://dx.doi.org/10.1257/jep.28.2.153.

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Uncertainty is an amorphous concept. It reflects uncertainty in the minds of consumers, managers, and policymakers about possible futures. It is also a broad concept, including uncertainty over the path of macro phenomena like GDP growth, micro phenomena like the growth rate of firms, and noneconomic events like war and climate change. In this essay, I address four questions about uncertainty. First, what are some facts and patterns about economic uncertainty? Both macro and micro uncertainty appear to rise sharply in recessions and fall in booms. Uncertainty also varies heavily across countries—developing countries appear to have about one-third more macro uncertainty than developed countries. Second, why does uncertainty vary during business cycles? Third, do fluctuations in uncertainty affect behavior? Fourth, has higher uncertainty worsened the Great Recession and slowed the recovery? Much of this discussion is based on research on uncertainty from the last five years, reflecting the recent growth of the literature.

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Mumtaz, Haroon, and Paolo Surico. "Policy uncertainty and aggregate fluctuations." Journal of Applied Econometrics 33, no. 3 (January 19, 2018): 319–31. http://dx.doi.org/10.1002/jae.2613.

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Pries, Michael J. "Uncertainty-driven labor market fluctuations." Journal of Economic Dynamics and Control 73 (December 2016): 181–99. http://dx.doi.org/10.1016/j.jedc.2016.09.003.

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Hua, Junguo, Hui Li, Zejun He, Jing Ding, and Futong Jin. "The Microcosmic Mechanism and Empirical Test of Uncertainty on the Non-Linear Fluctuation of Chinese Grain Prices-Based on the Perspective of Global Economic Policy Uncertainty." Agriculture 12, no. 10 (September 22, 2022): 1526. http://dx.doi.org/10.3390/agriculture12101526.

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The dramatic fluctuations in grain prices and the threat to grain security caused by global economic policy uncertainty have been a social concern and a challenging area for price management authorities to regulate. Based on general equilibrium analysis in microeconomics, this paper constructs a mathematical model of the impact of global economic policy uncertainty on grain price fluctuation. It then examines the micro mechanism of non-linear grain price fluctuation under the dominant market mechanism and measures the non-linear shock effect of global economic policy uncertainty on grain prices using a threshold regression model. The results show that soybean and corn prices are subject to a two-zone fluctuation pattern due to global economic policy uncertainty. The impact has significant non-linear characteristics and is significantly greater in the high zone than that in the low zone. Accordingly, this paper offers government departments advice on better regulating and managing the market supply and demand and smoothing out sharp fluctuations in grain prices caused by changes in global economic policies.

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Naixement, Luciano, and Carlos H. Béssa. "Quantum vacuum fluctuations in inorganic compound CdSe." MOMENTO, no. 66 (January 2, 2023): 23–40. http://dx.doi.org/10.15446/mo.n66.103486.

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In the present work, we study the quantum vacuum fluctuations at finite temperature in the propagation of light in nonlinear optical media. We present nonlinear materials, that have the second-order electrical susceptibility tensor, and the fluctuating effective refractive index caused by fluctuating vacuum electric fields. Likewise, we study the fluctuations of the vacuum, which led to the contributions of thermal and mixed fluctuations being associated with a faithful test function to perform the calculations, in contrast to the Lorentzian distribution. We show the contribution of thermal and mixed fluctuations to time-of-flight fluctuations compared to the contributions of vacuum fluctuations. The result reveals a numerical estimate performed on cadmium selenide (CdSe) suggesting that the effects of fluctuations can cause uncertainty in time of flight due to quantum vacuum fluctuations in terms of thermal and mixed fluctuations.

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Creal, Drew D., and Jing Cynthia Wu. "MONETARY POLICY UNCERTAINTY AND ECONOMIC FLUCTUATIONS." International Economic Review 58, no. 4 (November 2017): 1317–54. http://dx.doi.org/10.1111/iere.12253.

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Javaid, Saher, Mineo Kaneko, and Yasuo Tan. "Structural Condition for Controllable Power Flow System Containing Controllable and Fluctuating Power Devices." Energies 13, no. 7 (April 2, 2020): 1627. http://dx.doi.org/10.3390/en13071627.

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This paper discusses a structural property for a power system to continue a safe operation under power fluctuation caused by fluctuating power sources and loads. Concerns over global climate change and gas emissions have motivated development and integration of renewable energy sources such as wind and solar to fulfill power demand. The energy generated from these sources exhibits fluctuations and uncertainty which is uncontrollable. In addition, the power fluctuations caused by power loads also have the same consequences on power system. To mitigate the effects of uncontrollable power fluctuations, a power flow control is presented which allocates power levels for controllable power sources and loads and connections between power devices. One basic function for the power flow control is to balance the generated power with the power demand. However, due to the structural limitations, i.e., the power level limitations of controllable sources and loads and the limitation of power flow channels, the power balance may not be achieved. This paper proposes two theorems about the structural conditions for a power system to have a feasible solution which achieves the power balance between power sources and power loads. The discussions in this paper will provide a solid theoretical background for designing a power flow system which proves robustness against fluctuations caused by fluctuating power devices.

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Reiche, Daniel, Jen-Tsung Hsiang, and Bei-Lok Hu. "Quantum Thermodynamic Uncertainty Relations, Generalized Current Fluctuations and Nonequilibrium Fluctuation–Dissipation Inequalities." Entropy 24, no. 8 (July 23, 2022): 1016. http://dx.doi.org/10.3390/e24081016.

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Thermodynamic uncertainty relations (TURs) represent one of the few broad-based and fundamental relations in our toolbox for tackling the thermodynamics of nonequilibrium systems. One form of TUR quantifies the minimal energetic cost of achieving a certain precision in determining a nonequilibrium current. In this initial stage of our research program, our goal is to provide the quantum theoretical basis of TURs using microphysics models of linear open quantum systems where it is possible to obtain exact solutions. In paper [Dong et al., Entropy 2022, 24, 870], we show how TURs are rooted in the quantum uncertainty principles and the fluctuation–dissipation inequalities (FDI) under fully nonequilibrium conditions. In this paper, we shift our attention from the quantum basis to the thermal manifests. Using a microscopic model for the bath’s spectral density in quantum Brownian motion studies, we formulate a “thermal” FDI in the quantum nonequilibrium dynamics which is valid at high temperatures. This brings the quantum TURs we derive here to the classical domain and can thus be compared with some popular forms of TURs. In the thermal-energy-dominated regimes, our FDIs provide better estimates on the uncertainty of thermodynamic quantities. Our treatment includes full back-action from the environment onto the system. As a concrete example of the generalized current, we examine the energy flux or power entering the Brownian particle and find an exact expression of the corresponding current–current correlations. In so doing, we show that the statistical properties of the bath and the causality of the system+bath interaction both enter into the TURs obeyed by the thermodynamic quantities.

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Soret, Ariane, Ohad Shpielberg, and Eric Akkermans. "Uncertainty relations for mesoscopic coherent light." Journal of Statistical Mechanics: Theory and Experiment 2021, no. 12 (December 1, 2021): 123302. http://dx.doi.org/10.1088/1742-5468/ac3e6b.

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Abstract Thermodynamic uncertainty relations unveil useful connections between fluctuations in thermal systems and entropy production. This work extends these ideas to the disparate field of zero temperature quantum mesoscopic physics where fluctuations are due to coherent effects and entropy production is replaced by a cost function. The cost function arises naturally as a bound on fluctuations, induced by coherent effects—a critical resource in quantum mesoscopic physics. Identifying the cost function as an important quantity demonstrates the potential of importing powerful methods from non-equilibrium statistical physics to quantum mesoscopics.

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XU, XUE-XIANG, LI-YUN HU, and HONG-YI FAN. "FLUCTUATION OF MESOSCOPIC RLC CIRCUIT AT PHOTON-SUBTRACTED AND PHOTON-ADDED THERMO VACUUM STATES WITH FINITE TEMPERATURE." Modern Physics Letters B 25, no. 01 (January 10, 2011): 31–39. http://dx.doi.org/10.1142/s021798491102547x.

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By using the Wigner function to evaluate expectation values of any symmetrically order of operator in a classical fashion, we study the quantum fluctuation and the uncertainty relation of mesoscopic RLC circuit at photon-subtracted and photon-added thermo vacuum states. It is found that the fluctuations and the uncertainty relation of both charge and current are linearly related to the photon-subtracted and photon-added number.

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Fajar, Achmarul, and Siti Maulidah. "Fluktuasi Harga Dan Kesejahteraan Petani Tembakau Madura." JURNAL SOSIAL Jurnal Penelitian Ilmu-Ilmu Sosial 22, no. 1 (April 26, 2021): 19–23. http://dx.doi.org/10.33319/sos.v22i1.75.

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Abstractâ€” The growth of the cigarette industry does not necessarily improve the welfare of tobacco farmers Madura. Pamekasan as the largest tobacco center in Madura often experiences fluctuations of tobacco prices which have an impact on the economic uncertainty of tobacco farmers. The factors of fluctuating tobacco prices are the main topic of this research. This research on fluctuations of tobacco prices and the economy of Madura tobacco farmers used qualitative methods by searching for data directly in the field through semi-structured interviews. The result is that several factors have led to fluctuations of tobacco prices in the Pamekasan area. First, the factor of weather or climate change is uncertain. Second, the length of the tobacco distribution chain to the warehouses of major cigarette companies in Indonesia which are based in the Pamekasan area. Third, local regulation no. 4 of 2015 which is not consistently implemented so that tobacco farmers are not sovereign in determining the selling price of Madura tobacco. Keywordsâ€”: Fluctuations of Tobacco Prices; Madura Tobacco; The Economy of Madura Tobacco Farmers.

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Orlik, Anna, and Laura Veldkamp. "Understanding Uncertainty Shocks and the Role of Black Swans." Finance and Economics Discussion Series, no. 2022-083 (December 2022): 1–43. http://dx.doi.org/10.17016/feds.2022.083.

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Economic uncertainty is a powerful force in the modern economy. Research shows that surges in uncertainty can trigger business cycles, bank runs and asset price fluctuations. But where do sudden surges in uncertainty come from? This paper provides a data-disciplined theory of belief formation that explains large fluctuations in uncertainty. It argues that people do not know the true distribution of macroeconomic outcomes. Like Bayesian econometricians, they estimate a distribution. Our main contribution is to explain why real-time estimation of distributions with non-normal tails results in large uncertainty fluctuations. We use theory and data to show how small changes in estimated skewness whip around probabilities of unobserved tail events (black swans). Our estimates, based on real-time GDP data, reveal that revisions in the estimates of black swan risk explain most of the fluctuations in uncertainty.

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Raheem, Mian Numan, and M. Adrees. "The Effect of Risk and Uncertainty Factors on Managerial Decision Making." Journal of Education and Vocational Research 12, no. 1(V) (November 16, 2021): 30–37. http://dx.doi.org/10.22610/jevr.v12i1(v).3239.

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This study evaluated the effect of risk and uncertainty factors on financial decision making. The long-term goals and ways for achievement are constantly attached with uncertainty since we don’t know the circumstances, either positive or negative, which happen later. Uncertainty is a key logical factor that influences the dynamic. The reason for this investigation is to check how risk and factors of uncertainty impact the financial aspects of a firm. The risk factors incorporate, financial risk, market fluctuations hazards, fluctuation of unfamiliar and loan costs. Uncertainty factors incorporate political, monetary and environmental uncertainty. The results reveal that management knowledge and expertise related to these factors are utmost important for effective decision making and sustainable growth.

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15

Horowitz, Jordan M., and Todd R. Gingrich. "Thermodynamic uncertainty relations constrain non-equilibrium fluctuations." Nature Physics 16, no. 1 (November 11, 2019): 15–20. http://dx.doi.org/10.1038/s41567-019-0702-6.

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Alessandria, George, Horag Choi, Joseph P. Kaboski, and Virgiliu Midrigan. "Microeconomic uncertainty, international trade, and aggregate fluctuations." Journal of Monetary Economics 69 (January 2015): 20–38. http://dx.doi.org/10.1016/j.jmoneco.2014.11.007.

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Saavedra, Luis Gerardo Pedraza. "Vacuum fluctuations in charge–current uncertainty relations." Journal of Russian Laser Research 32, no. 5 (September 2011): 476–85. http://dx.doi.org/10.1007/s10946-011-9237-8.

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Malley, Jim, Apostolis Philippopoulos, and Ulrich Woitek. "Electoral uncertainty, fiscal policy and macroeconomic fluctuations." Journal of Economic Dynamics and Control 31, no. 3 (March 2007): 1051–80. http://dx.doi.org/10.1016/j.jedc.2006.06.004.

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19

Houssa, Romain. "Uncertainty about welfare effects of consumption fluctuations." European Economic Review 59 (April 2013): 35–62. http://dx.doi.org/10.1016/j.euroecorev.2012.12.006.

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Pitaevskii, L., and S. Stringari. "Uncertainty principle, quantum fluctuations, and broken symmetries." Journal of Low Temperature Physics 85, no. 5-6 (December 1991): 377–88. http://dx.doi.org/10.1007/bf00682193.

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Kitchatinov, L. L., A. V. Mordvinov, and A. A. Nepomnyashchikh. "Modelling variability of solar activity cycles." Astronomy & Astrophysics 615 (July 2018): A38. http://dx.doi.org/10.1051/0004-6361/201732549.

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Context. Solar activity cycles vary in amplitude and duration. The variations can be at least partly explained by fluctuations in dynamo parameters. Aims. We want to restrict uncertainty in fluctuating dynamo parameters and find out which properties of the fluctuations control the amplitudes of the magnetic field and energy in variable dynamo cycles. Methods. A flux-transport model for the solar dynamo with fluctuations of the Babcock–Leighton type α-effect was applied to generate statistics of magnetic cycles for our purposes. The statistics were compared with data on solar cycle periods to restrict the correlation time of dynamo fluctuations. Results. A characteristic time of fluctuations in the α-effect is estimated to be close to the solar rotation period. The fluctuations produce asymmetry between the times of rise and descent of dynamo cycles, the rise time being on average shorter. The affect of the fluctuations on cycle amplitudes depends on the phase of the cycle in which the fluctuations occur. Negative fluctuations (decrease in α) in the rise phase delay decay of poloidal field and increase the cycle amplitude in toroidal field and magnetic energy. Negative fluctuation in the decline phase reduces the polar field at the end of a cycle and the amplitude of the next cycle. The low amplitude of the 24th solar cycle compared to the preceding 23rd cycle can be explained by this effect. Positive fluctuations in the descent phase enhance the magnetic energy of the next cycle by increasing the seed poloidal field for the next cycle. The statistics of the computed energies of the cycles suggest that superflares of ≥1034 erg are not possible on the Sun.

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Phan, Mai Ha, and Tai Duc Nguyen. "Capacity Planning Considering Uncertainty Factors." Applied Mechanics and Materials 907 (June 22, 2022): 145–54. http://dx.doi.org/10.4028/p-5zt84o.

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Capacity planning is the process of determining the production capacity needed by an organization to meet changing demands for its products. Production capacity planning is generally based on all capabilities determining that wireless production is stable, with no fluctuations in machine downtime, variable processing times, defective products, etc., and use the mean for cycle time. However, actual production not only has many fluctuations in human resources that affecting the production time on each stage, but also affected by defective products leading to inaccurate planning. Therefore, planning production capacity under uncertain conditions is essential for any manufacturing enterprise. This paper proposes a model of capacity planning in uncertain conditions using real-time observation and then distributing observation time from which to analyze production capacity. Uncertainty factor as labor and defective products will be considered in this model.

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Marsland, Robert, Wenping Cui, and Jordan M. Horowitz. "The thermodynamic uncertainty relation in biochemical oscillations." Journal of The Royal Society Interface 16, no. 154 (May 2019): 20190098. http://dx.doi.org/10.1098/rsif.2019.0098.

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Living systems regulate many aspects of their behaviour through periodic oscillations of molecular concentrations, which function as ‘biochemical clocks.’ The chemical reactions that drive these clocks are intrinsically stochastic at the molecular level, so that the duration of a full oscillation cycle is subject to random fluctuations. Their success in carrying out their biological function is thought to depend on the degree to which these fluctuations in the cycle period can be suppressed. Biochemical oscillators also require a constant supply of free energy in order to break detailed balance and maintain their cyclic dynamics. For a given free energy budget, the recently discovered ‘thermodynamic uncertainty relation’ yields the magnitude of period fluctuations in the most precise conceivable free-running clock. In this paper, we show that computational models of real biochemical clocks severely underperform this optimum, with fluctuations several orders of magnitude larger than the theoretical minimum. We argue that this suboptimal performance is due to the small number of internal states per molecule in these models, combined with the high level of thermodynamic force required to maintain the system in the oscillatory phase. We introduce a new model with a tunable number of internal states per molecule and confirm that it approaches the optimal precision as this number increases.

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Artamonov, Anton А., and Еvgeny Plotnikov. "THERMODYNAMIC UNCERTAINTY RELATION AS A FUNDAMENTAL ASPECT OF QUANTUM THERMODYNAMICS." Resource-Efficient Technologies, no. 1 (March 20, 2018): 17–29. http://dx.doi.org/10.18799/24056537/2018/1/178.

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The paper addresses physics of thermodynamic fluctuations in temperature and energy. These fluctuations are interrelated and, hence, can affect various micro- and macro systems. It is shown that the thermodynamic uncertainty relation must be taken into account in the physics of superconductivity, in quantum computations and other branches of science, where temperature and energy fluctuations play a critical role. One of the most important applications of quantum thermodynamics is quantum computers. It is assumed that in the near future the state structures will create a specific quantum cryptocurrency obtained using quantum computing. The quantum cryptocurrency exhibits two main features: the maximum reliability (quantum protection against hacking threats) and the possibility of state control (at the moment, only large scientific state centers have quantum computers). The paper reviews the studies aimed to theoretically prove the validity of the thermodynamic uncertainty relation. This relation connects fluctuations in temperature and energy of a system. Other similar relations are considered, including the relationship between fluctuations in pressure and volume, in entropy and temperature, and others. The main purpose of the paper is to validate the thermodynamic analogue of the uncertainty relation that interconnects temperature and energy fluctuations. Experimental data was obtained on the basis of the study of the transport properties of semiconductor devices – transistors. In the experiment, the transport properties of a pair of semiconductor transistors placed on a single silicon crystal were studied. In this system, one transistor was used to determine temperature fluctuations, and the other one was employed to estimate energy fluctuations. The key role of the thermodynamic uncertainty relation in modern thermodynamics has been clarified. The performed experimental studies confirm the validity of the thermodynamic uncertainty relation.

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Thiel, Felix, Itay Mualem, David Kessler, and Eli Barkai. "Uncertainty Relation between Detection Probability and Energy Fluctuations." Entropy 23, no. 5 (May 11, 2021): 595. http://dx.doi.org/10.3390/e23050595.

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A classical random walker starting on a node of a finite graph will always reach any other node since the search is ergodic, namely it fully explores space, hence the arrival probability is unity. For quantum walks, destructive interference may induce effectively non-ergodic features in such search processes. Under repeated projective local measurements, made on a target state, the final detection of the system is not guaranteed since the Hilbert space is split into a bright subspace and an orthogonal dark one. Using this we find an uncertainty relation for the deviations of the detection probability from its classical counterpart, in terms of the energy fluctuations.

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Jaroslav, Zajac. "Uncertainty fluctuations and multi-agent economies with equilibrium." Applied Economics Letters 11, no. 6 (May 15, 2004): 397–400. http://dx.doi.org/10.1080/1350485042000228277.

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Fawaz, Fadi, Masha Rahnamamoghadam, and Victor Valcarcel. "Fluctuations, Uncertainty and Income Inequality in Developing Countries." Eastern Economic Journal 38, no. 4 (February 20, 2012): 495–511. http://dx.doi.org/10.1057/eej.2011.32.

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Messerer, Katharina, Tim Kacprowski, Horst Kolo, Jan Baumbach, and Thomas Knoke. "Importance of considering the growth response after partial harvesting and economic risk of discounted net revenues when optimizing uneven-aged forest management." Canadian Journal of Forest Research 50, no. 5 (May 2020): 487–99. http://dx.doi.org/10.1139/cjfr-2018-0546.

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Because of the very high complexity of modern optimization models based on single trees, uncertainties are often disregarded. In this study, we present a modelling approach that allows partial harvesting but is still simple enough to consider risk. Our modelling approach investigates whether the inclusion of timber price uncertainty influences the harvesting schedule. The model considers positive growth response to the density reduction that follows harvesting. Testing the impact of uncertainty, we define the discounted net revenues of each harvest operation as random variables. We compare harvest scheduling both with and without the inclusion of uncertainty. We first model growth response based on a partial-harvest schedule, without integrating uncertainty from timber price fluctuations. The results show that harvesting tree cohorts at different times is financially optimal. We run the same model again, including the risk of timber price fluctuations. The inclusion of risk leads to slightly greater differences in recommended harvest timings. Because of the small difference observed, we conclude that it is unlikely that risk arising from fluctuating timber prices would strongly affect the results for more complex forest economic models concerning the optimal harvest schedules.

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Vo, Van Tuan, Tan Van Vu, and Yoshihiko Hasegawa. "Unified thermodynamic–kinetic uncertainty relation." Journal of Physics A: Mathematical and Theoretical 55, no. 40 (September 29, 2022): 405004. http://dx.doi.org/10.1088/1751-8121/ac9099.

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Abstract Understanding current fluctuations is of fundamental importance and paves the way for the development of practical applications. According to the thermodynamic and kinetic uncertainty relations, the precision of currents can be constrained solely by the total entropy production or dynamical activity. In this study, we derive a tighter bound on the precision of currents in terms of both thermodynamic and kinetic quantities, demonstrating that these quantities jointly constrain current fluctuations. The thermodynamic and kinetic uncertainty relations become particular cases of our result in asymptotic limits. Intriguingly, the unified thermodynamic–kinetic uncertainty relation leads to a tighter classical speed limit, refining the time constraint on the system’s state transformation. The proposed framework can be extended to apply to state observables and systems with unidirectional transitions, thereby providing a constraint on the precision of the first-passage time.

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Zhang, Yi Hui. "The Research of Wind Power Fluctuation in Different Time Intervals." Advanced Materials Research 953-954 (June 2014): 458–61. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.458.

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Power from wind turbines is mainly related to the wind speed. Due to the influence of the uncertainty of the wind, intermittent and wind farm in units of the wake, wind power has fluctuations. Based on the field measurement, it is found that t location-scale distribution is suitable to identify the probability distribution of wind power variations. By analyzing the fluctuation of a single in different time intervals, we find that the distribution of wind power fluctuation possesses a certain trend pattern. With the length of the time window increasing, the fluctuations increase and some information has been missed. We define an index to calculate the quantity of missing information and can use that to evaluate whether a certain length of interval is acceptable.

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Ding, Yan, Yue Liu, and Pierre Failler. "The Impact of Uncertainties on Crude Oil Prices: Based on a Quantile-on-Quantile Method." Energies 15, no. 10 (May 11, 2022): 3510. http://dx.doi.org/10.3390/en15103510.

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There has always been a complex relationship between uncertainty and crude oil prices. Three types of uncertainty, i.e., economic policy uncertainty, geopolitical risk uncertainty, and climate policy uncertainty (EPU, GPR, and CPU for short), have exacerbated abnormal fluctuations in the energy market, making crude oil prices volatile more and more frequently, especially from the perspective of the financial attribute of crude oil. Based on the time-series data related to uncertainties and crude oil prices from December 2001 to March 2021, this paper uses the quantile-on-quantile regression (QQR) method to explore the overall impact of various uncertainties on crude oil prices. Moreover, this paper adopts the QQR method based on the wavelet transform to investigate the heterogeneous effects of various uncertainties on crude oil prices at different time scales. The following conclusions are obtained. First, there are significant differences in the overall impact of the three types of uncertainties on crude oil prices, and this heterogeneity is reflected in quantiles of the peak impact intensity, the impact direction, and the fluctuation change. Second, the impact intensities of the three types of uncertainties on crude oil prices are significantly different at different time scales. This is mainly reflected in the different periods of significant impact of the three uncertainties on crude oil prices. Third, the impact directions and fluctuations of the three types of uncertainties on crude oil prices are heterogeneous at different time scales.

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Vidal, F., M. V. Ramallo, J. Mosqueira, and C. Carballeira. "Superconducting Fluctuations Above TC and the Uncertainty Principle: How Small may the Coherence Length be?" International Journal of Modern Physics B 17, no. 18n20 (August 10, 2003): 3470–72. http://dx.doi.org/10.1142/s0217979203021228.

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We summarize here some of our recent results on the superconducting fluctuation effects above TC in different low- and high-TC superconductors, at high reduced-temperatures and magnetic fields. These results confirm our proposal that the collective behaviour of the fluctuating Cooper pairs in the short-wavelength fluctuation regime is dominated by the uncertainty principle, which imposes a limit to the shrinkage of the superconducting wave function when T increases well above TC or H becomes of the order of Hc2(0), the upper critical magnetic field amplitude extrapolated to T = 0 K .

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Sidek, Noor Zahirah Mohd, Bhuk Kiranantawat, and Martusorn Khaengkhan. "The Impact of Uncertainty on Trade: The Case for a Small Port." Economies 10, no. 8 (August 8, 2022): 193. http://dx.doi.org/10.3390/economies10080193.

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In the present paper, we show how uncertainty emanating from fluctuations in economic uncertainty, news-based uncertainty, and geopolitical risks affect the number of containers exported from Thailand via Penang Port, Malaysia. Our sample extends from January 2009 to May 2020 from three main entry points in the Northern Peninsular Malaysia–Thailand Border: Padang Besar, Surat Thani, and Bukit Kayu Hitam. Two modes of transportation of containers are mainly used for export purposes, namely, road and rai. This study examines the nonlinear effect of uncertainty on trade by employing a two-regime Markov regime-switching approach. The empirical results show that, overall, uncertainty significantly affects the movement of containers in the high-uncertainty regime. Therefore, small ports must continue to diversify their client base to cushion the impact of fluctuations in global trade due to uncertainty.

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Chow, Yee Peng, Junaina Muhammad, Bany Ariffin Amin Noordin, and Fan Fah Cheng. "Macroeconomic Uncertainty in South East Asia: A Comparative Study between Malaysia and Indonesia." Research in Applied Economics 9, no. 4 (November 16, 2017): 1. http://dx.doi.org/10.5296/rae.v9i4.11187.

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This paper examines the historical pattern of macroeconomic uncertainty of two developing countries in the South East Asia, namely Malaysia and Indonesia. Comparisons of macroeconomic uncertainty are also made between both countries using a selected number of indicators for macroeconomic volatility. We find that while both countries were affected by similar external sources of macroeconomic uncertainty, these countries were also subject to domestic sources of macroeconomic uncertainty which were confined to the particular country. The analyses also reveal that Indonesia experienced more fluctuations compared to Malaysia when macroeconomic uncertainty is measured by volatility as a macroeconomic outcome and domestic sources of macroeconomic volatility. Contrarily, Malaysia displayed greater fluctuations than Indonesia when macroeconomic uncertainty is measured by external sources of macroeconomic volatility. Policy implications are drawn from the findings.

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Horowitz, Jordan M., and Todd R. Gingrich. "Author Correction: Thermodynamic uncertainty relations constrain non-equilibrium fluctuations." Nature Physics 16, no. 5 (March 9, 2020): 599. http://dx.doi.org/10.1038/s41567-020-0853-5.

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JAFARI, G. R., M. SADEGH MOVAHED, P. NOROUZZADEH, A. BAHRAMINASAB, MUHAMMAD SAHIMI, F. GHASEMI, and M. REZA RAHIMI TABAR. "UNCERTAINTY IN THE FLUCTUATIONS OF THE PRICE OF STOCKS." International Journal of Modern Physics C 18, no. 11 (November 2007): 1689–97. http://dx.doi.org/10.1142/s0129183107011662.

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We report on a study of the Tehran Price Index (TEPIX) from 2001 to 2006 as an emerging market that has been affected by several political crises during the recent years, and analyze the non-Gaussian probability density function (PDF) of the log returns of the stock prices. We show that while the average of the index did not fall very much over the time period of the study, its day-to-day fluctuations strongly increased due to the crises. Using an approach based on multiplicative processes with a detrending procedure, we study the scale-dependence of the non-Gaussian PDFs, and show that the temporal dependence of their tails indicates a gradual and systematic increase in the probability of the appearance of large increments in the returns on approaching distinct critical time scales over which the TEPIX has exhibited maximum uncertainty.

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37

Nowzohour, Laura, and Livio Stracca. "MORE THAN A FEELING: CONFIDENCE, UNCERTAINTY, AND MACROECONOMIC FLUCTUATIONS." Journal of Economic Surveys 34, no. 4 (June 20, 2020): 691–726. http://dx.doi.org/10.1111/joes.12354.

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38

Lustig, Hanno. "Discussion of ‘Microeconomic uncertainty, international trade and aggregate fluctuations’." Journal of Monetary Economics 69 (January 2015): 39–41. http://dx.doi.org/10.1016/j.jmoneco.2014.12.009.

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O'Brien, Gabrielle, and Matthew Winn. "Uncertainty in binaural hearing linked to inherent envelope fluctuations." Journal of the Acoustical Society of America 140, no. 4 (October 2016): 3100. http://dx.doi.org/10.1121/1.4969670.

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40

Zhu, X., and H. D. Sherali. "Two-stage workforce planning under demand fluctuations and uncertainty." Journal of the Operational Research Society 60, no. 1 (January 2009): 94–103. http://dx.doi.org/10.1057/palgrave.jors.2602522.

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41

François, Manuel, C. Ferreira, and Ronald Guillén. "Effects of Temperature Fluctuations on X-Ray Stress Determination." Materials Science Forum 490-491 (July 2005): 183. http://dx.doi.org/10.4028/www.scientific.net/msf.490-491.183.

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The results presented in this paper are part of a process to analyse systematically the sources of uncertainty in X-ray stress determination. They concern one part of the effects of temperature variations which could intervene either as random fluctuations or as a monotonic drift during the acquisition. The proposed formulation is in agreement with the recommendations of the ISO guide on the expression of uncertainty (GUM). It was found that the effect is usually negligible for laboratory experiments which are often temperature controlled and for most materials. However the uncertainty can reach 20 MPa for austenitic steels and a temperature drift of 2 K.

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42

Giné, Jaume. "Casimir effect and the uncertainty principle." Modern Physics Letters A 33, no. 24 (August 3, 2018): 1850140. http://dx.doi.org/10.1142/s0217732318501407.

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The Casimir effect is one of the observable consequences of the vacuum fluctuations. The Casimir effect manifests itself as a force between two uncharged conductive plates in a vacuum placed a few nanometers apart. In this work, we try to deduce the Casimir effect directly from the uncertainty principle.

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43

Kuzmichev, V. E., and V. V. Kuzmichev. "Generalized Uncertainty Principle in Quantum Cosmology for the Maximally Symmetric Space." Ukrainian Journal of Physics 64, no. 2 (February 21, 2019): 100. http://dx.doi.org/10.15407/ujpe64.2.100.

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The new uncertainty relation is derived in the context of the canonical quantum theory with gravity in the case of the maximally symmetric space. This relation establishes a connection between fluctuations of the quantities, which determine the intrinsic and extrinsic curvatures of the spacelike hypersurface in spacetime and introduces the uncertainty principle for quantum gravitational systems. The generalized time-energy uncertainty relation taking gravity into account gravity is proposed. It is shown that known Unruh’s uncertainty relation follows, as a particular case, from the new uncertainty relation. As an example, the sizes of fluctuations of the scale factor and its conjugate momentum are calculated within an exactly solvable model. All known modifications of the uncertainty principle deduced previously from different approaches in the theory of gravity and the string theory are obtained as particular cases of the proposed general expression.

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44

Melzer, Christiane Marianne, Martin Krech, Lisa Kristl, Tillmann Freund, Anja Kuttich, Maximilian Zocholl, Peter Groche, Michael Kohler, and Roland Platz. "Methodical Approaches to Describe and Evaluate Uncertainty in the Transmission Behavior of a Sensory Rod." Applied Mechanics and Materials 807 (November 2015): 205–17. http://dx.doi.org/10.4028/www.scientific.net/amm.807.205.

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Load carrying mechanical structures like trusses face uncertainty in loading along with uncertainty in their strength due to uncertainty in the development, production and usage. The uncertainty in production of function integrated rods is investigated, which allows monitoring of load and condition variations that are present in the product in every phase of its lifetime. Due to fluctuations of the semi-finished parts, uncertainty in governing geometrical, mechanical and electrical properties such as Young's moduli, lengths and piezoelectric charge constants has to be evaluated. The authors compare the different direct methodical approaches Monte-Carlo simulation, fuzzy and interval arithmetic to describe and to evaluate this uncertainty in the development phase of a simplified, linear mathematical model of a sensory rod in a consistent way. The criterion to compare the methodical approaches for uncertainty analysis is the uncertain mechanical-electrical transmission behavior of the sensory rod, which defines the sensitivity of the sensory compound.

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45

Mousavi, Seyed Nasrollah, Davood Farsadizadeh, Farzin Salmasi, Ali Hosseinzadeh Dalir, and Daniele Bocchiola. "Analysis of minimal and maximal pressures, uncertainty and spectral density of fluctuating pressures beneath classical hydraulic jumps." Water Supply 20, no. 5 (May 20, 2020): 1909–21. http://dx.doi.org/10.2166/ws.2020.098.

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Abstract Knowledge of extreme pressures and fluctuations within stilling basins is of the utmost importance, as they may cause potential severe damages. It is complicated to measure the fluctuating pressures of hydraulic jumps in real-scale structures. Therefore, little information is available about the pressure fluctuations in the literature. In this paper, minimal and maximal pressures were analyzed on the flat bed of a stilling basin downstream of an Ogee spillway. Attention has been focused on dimensionless pressures related to the low and high cumulative probabilities of occurrence (P*0.1% and P*99.9%), respectively. The results were presented based on the laboratory-scale experiments. These parameters for the relatively high Froude numbers have not been investigated. The total standard uncertainty for the dimensionless mean pressures (P*m) was obtained around 1.87%. Spectral density analysis showed that the dominant frequency in the classical hydraulic jumps was about 4 HZ. Low-frequency of pressure fluctuations indicated the existence of large-scale vortices. In the zone near the spillway toe, P*0.1% reached negative values of around −0.3. The maximum values of pressure coefficients, namely |CP0.1%|max and CP99.9%max, were achieved around 0.19 and 0.24, respectively. New original expressions were proposed for P*0.1% and P*99.9%, which are useful for estimating extreme pressures.

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Liao, Shijun, and Xiaoming Li. "On the Inherent Self-Excited Macroscopic Randomness of Chaotic Three-Body Systems." International Journal of Bifurcation and Chaos 25, no. 09 (August 2015): 1530023. http://dx.doi.org/10.1142/s0218127415300232.

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What is the origin of macroscopic randomness (uncertainty)? This is one of the most fundamental open questions for human beings. In this paper, 10 000 samples of reliable (convergent), multiple-scale (from 10-60 to 102) numerical simulations of a chaotic three-body system indicate that, without any external disturbance, the microscopic inherent uncertainty (in the level of 10-60) due to physical fluctuation of initial positions of the three-body system enlarges exponentially into macroscopic randomness (at the level O(1)) until t = T*, the so-called physical limit time of prediction, but propagates algebraically thereafter when accurate prediction of orbit is impossible. Note that these 10 000 samples use micro-level, inherent physical fluctuations of initial position, which have nothing to do with human beings. Especially, the differences of these 10 000 fluctuations are mathematically so small (in the level of 10-60) that they are physically the same since a distance shorter than a Planck length does not make physical sense according to the string theory. This indicates that the macroscopic randomness of the chaotic three-body system is self-excited, say, without any external force or disturbances, from the inherent micro-level uncertainty. It provides us the new concept "self-excited macroscopic randomness (uncertainty)". The macroscopic randomness is found to be dependent upon microscopic uncertainty, from the statistical viewpoint. In addition, it is found that, without any external disturbance, the chaotic three-body system might randomly disrupt with symmetry-breaking at t = 1000 in about 25% probability, which provides us new concepts "self-excited random disruption", "self-excited random escape" and "self-excited symmetry breaking" of the chaotic three-body system. Hence, it suggests that a chaotic three-body system might randomly evolve by itself, without any external forces or disturbance. Thus, the world is essentially uncertain, since such kind of self-excited macroscopic randomness (uncertainty) is inherent and unavailable. This work also implies that an universe could randomly evolve by itself into complicated structures, without any external forces. To emphasize this point, the so-called "molecule-effect" (or "nonbutterfly effect") of chaos is suggested in this paper. All of these reliable computations could deepen our understandings of chaos from physical viewpoints, and reveal a kind of origin of macroscopic randomness/uncertainty.

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Zhang, Jinping, Yong Zhao, and Xiaomin Lin. "Uncertainty analysis and prediction of river runoff with multi-time scales." Water Supply 17, no. 3 (November 28, 2016): 897–906. http://dx.doi.org/10.2166/ws.2016.190.

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Increasing water-issues demand that water resources managers know and predict the uncertain characteristics of river runoff well. In this paper, the fluctuating periods and local features of runoff with multi-time scales are analyzed by the empirical mode decomposition method. With the set pair analysis method, the uncertainty properties of runoff series with different multi-time scales are expressed. Meanwhile, cointegration theory is introduced to indicate the long-term equilibrium relationships between runoff series, and then the runoff prediction model is proposed based on the error correction model (ECM). The results show that the runoff series of Heihe River in northwest China exhibit complex relations with different periodic fluctuations and changing laws. The identity degree is the main relation between two runoff series, especially in the short period. Both the original series and decomposed components are all cointegrated, and the established runoff prediction model based on the ECM can simulate and predict river runoff well.

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48

Sedláček, Petr. "Creative Destruction and Uncertainty." Journal of the European Economic Association 18, no. 4 (August 13, 2019): 1814–43. http://dx.doi.org/10.1093/jeea/jvz047.

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Abstract Uncertainty rises in recessions. But does uncertainty cause downturns or vice versa? This paper argues that counter-cyclical uncertainty fluctuations are a by-product of technology growth. In a firm dynamics model with endogenous technology adoption, faster technology growth widens the dispersion of firm-level productivity shocks, a benchmark uncertainty measure. Moreover, faster technology growth spurs a creative destruction process, generates a temporary downturn, and renders uncertainty counter-cyclical. Estimates from structural vector autoregressions (VARs) on U.S. data confirm the model’s predictions. On average, 1/4 of the cyclical variation in uncertainty is driven by technology shocks. This fraction rises to 2/3 around the “dot-com” bubble.

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Beretta, Gian Paolo. "Time–Energy and Time–Entropy Uncertainty Relations in Nonequilibrium Quantum Thermodynamics under Steepest-Entropy-Ascent Nonlinear Master Equations." Entropy 21, no. 7 (July 11, 2019): 679. http://dx.doi.org/10.3390/e21070679.

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In the domain of nondissipative unitary Hamiltonian dynamics, the well-known Mandelstam–Tamm–Messiah time–energy uncertainty relation τ F Δ H ≥ ℏ / 2 provides a general lower bound to the characteristic time τ F = Δ F / | d ⟨ F ⟩ / d t | with which the mean value of a generic quantum observable F can change with respect to the width Δ F of its uncertainty distribution (square root of F fluctuations). A useful practical consequence is that in unitary dynamics the states with longer lifetimes are those with smaller energy uncertainty Δ H (square root of energy fluctuations). Here we show that when unitary evolution is complemented with a steepest-entropy-ascent model of dissipation, the resulting nonlinear master equation entails that these lower bounds get modified and depend also on the entropy uncertainty Δ S (square root of entropy fluctuations). For example, we obtain the time–energy-and–time–entropy uncertainty relation ( 2 τ F Δ H / ℏ ) 2 + ( τ F Δ S / k B τ ) 2 ≥ 1 where τ is a characteristic dissipation time functional that for each given state defines the strength of the nonunitary, steepest-entropy-ascent part of the assumed master equation. For purely dissipative dynamics this reduces to the time–entropy uncertainty relation τ F Δ S ≥ k B τ , meaning that the nonequilibrium dissipative states with longer lifetime are those with smaller entropy uncertainty Δ S .

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Wu, Honghong, Chuanyi Tu, Xin Wang, and Liping Yang. "Magnetic and Velocity Fluctuations in the Near-Sun Region from 0.1−0.3 au Observed by Parker Solar Probe." Astrophysical Journal 922, no. 2 (November 26, 2021): 92. http://dx.doi.org/10.3847/1538-4357/ac3331.

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Abstract The fluctuations observed in the slow solar wind at 1 au by the WIND spacecraft are shown by recent studies to consist of mainly magnetic-field directional turning and magnetic-velocity alignment structure (MVAS). How these structures are created has been a question because the nature of the fluctuations in the near-Sun region remains unknown. Here, we present an analysis of the measurements in the slow solar wind from 0.1−0.3 au by Parker Solar Probe during its first six orbits. We present the distributions in the C vb ′ – σ r plane of both the occurrence and average amplitudes of the fluctuations, including the magnetic field, the velocity, and the Elsässer variables, where C vb ′ is the correlation coefficient between the magnetic and velocity fluctuations multiplied by the opposite sign of the radial component of the mean magnetic field and σ r is the normalized residual energy. We find that the dominant composition is the outward-propagating Alfvénic fluctuations. We find Alfvénic fluctuations with C vb ′ > 0.95 , in which the amplitudes of z + reach 60 km s−1 and those of z − are close to the observational uncertainty. We also find a region with high C vb ′ and moderate minus σ r in which the fluctuations are considered MVAS being magnetic dominated with the amplitude of magnetic fluctuations reaching 60 km s−1. We provide empirical relations between the velocity fluctuation amplitude and C vb ′ . The comparison between these results and those observed at 1 au may provide some clues as to the nature and evolution of the fluctuations.

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Journal articles on the topic 'Uncertainty and fluctuations'

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