This document discusses stochastic models of movement and search behavior. It begins by describing how Karl Pearson originally connected animal motion to random walks over a century ago. It then discusses how the Brownian motion and random walk paradigm dominated modeling of movement in biology. It introduces the continuous time random walk as an exemplar model and discusses how variations were developed to better capture biological data. The document notes that some data shows anomalous diffusion patterns that motivate considering non-Brownian models involving Lévy flights with heavy-tailed jump lengths or fractional time processes with heavy-tailed waiting times. It discusses how these can be combined and gives examples fitting these models to data. It concludes by discussing the Lévy foraging hypothesis proposing these models may confer evolutionary advantages.
2015 Dresden Mandelbrot's other route to1 over fNick Watkins
Mandelbrot made important contributions to understanding the phenomenon of 1/f noise through several models between 1963-1972:
1) He proposed heavy-tailed distributions to explain wild fluctuations in cotton prices (1963) and the Hurst effect in Nile river levels.
2) This led to his fractional Gaussian noise (fGn) and fractional Brownian motion models which produce a 1/f spectral shape through long-range dependence or self-similarity (1965-1968). These stationary and non-stationary models were controversial due to their singular power spectra.
3) Less well known are his "conditionally stationary" models from 1963-1967 which achieved 1/f noise through long-tailed waiting times
2014 Wroclaw Mandelbrot's Other Model of 1/f NoiseNick Watkins
1) Mandelbrot gave an invited talk discussing several of his models for 1/f noise processes, including fractional Brownian motion (fBm) and fractional Gaussian noise (fGn) which introduced the concept of long-range dependence.
2) However, he later emphasized that reducing 1/f noise solely to the property of self-similarity was an oversimplification. His other models, like fractional hyperbolic motion and multiplicative multifractal cascades, exhibited different visual properties.
3) One lesser known class was his "dustborne" models from 1965-1967, which involved renewal processes with heavy-tailed waiting times. These exhibited properties like ergodicity breaking and time-dependent power spectra
The document discusses different aspects and theories of time travel, including:
1) It explores Einstein's theory of general relativity which seems to allow for the possibility of backwards time travel if space-time can curve enough.
2) It addresses that going forward in time is relatively easy, while going backwards is much harder due to the challenges of significantly warping space-time.
3) The document discusses that time travel may be possible if there are differences in the flow of time between people, for example if one was able to travel at speeds close to the speed of light relative to others.
2014 OU Mandelbrot's eyes and 1/f noiseNick Watkins
The document discusses Benoit Mandelbrot's work on modeling wild fluctuations and long-range dependence that he observed in various real-world datasets. It describes how his initial attempts to explain these phenomena with heavy-tailed distributions and fractional Brownian motion led him to abstract the property of self-similarity in the spectral domain. The document also notes that Mandelbrot warned against over-interpreting any single property and advocated using our eyes alongside formulas to fully understand complexity.
This article aims to present possible strategies for humanity to seek its survival with the end of the Universe in which we live. Research on the fate of our Universe, on the existence or not of multiverse or parallel universes and on the development of the final theory or theory of everything, that is, of the theory of the unified field, are important questions to elucidate in order to point out possible strategies for humanity seeks its survival with the end of the Universe in which we live.
The document discusses various concepts and theories related to time travel. It begins by defining time travel as moving between different points in time analogous to moving between different points in space, potentially using a time machine. It then discusses Einstein's theories of special and general relativity which established that time is relative and affected by speed and gravity. The document considers some potential ways to achieve time travel, such as moving faster than light, traveling through wormholes or black holes, but also notes significant challenges like paradoxes. It provides examples of depictions of time travel in science fiction films to help explain these complex theoretical physics concepts.
This PowerPoint discusses different theories and concepts related to time travel. It begins by defining time travel as moving between different points in time analogous to moving between different points in space, either sending objects backwards or forwards without experiencing the intervening time. It notes that general and special relativity suggest time travel could be possible through suitable geometries of space-time or specific types of motion. It also discusses wormholes and closed time-like curves as hypothetical concepts permitted by general relativity that could allow time travel. Finally, it briefly discusses some potential futures a time traveler might encounter, such as robots, cyborgs, flying cars, and aliens.
Can the vacuum be engineered for space flight applications by h.e.puthoffPublicLeaker
1) The document discusses theories and experiments regarding zero-point energy (ZPE) in the quantum vacuum and possibilities for engineering the vacuum for applications like space propulsion.
2) Several approaches are proposed for tapping into ZPE as an energy source, including exploiting the Casimir effect and sonoluminescence. Experiments on these approaches are ongoing.
3) The author proposes that vacuum fluctuations may be the source of fundamental forces like gravity and inertia, and that engineering the vacuum could therefore influence these forces with implications for space travel like reducing spacecraft mass.
2015 Dresden Mandelbrot's other route to1 over fNick Watkins
Mandelbrot made important contributions to understanding the phenomenon of 1/f noise through several models between 1963-1972:
1) He proposed heavy-tailed distributions to explain wild fluctuations in cotton prices (1963) and the Hurst effect in Nile river levels.
2) This led to his fractional Gaussian noise (fGn) and fractional Brownian motion models which produce a 1/f spectral shape through long-range dependence or self-similarity (1965-1968). These stationary and non-stationary models were controversial due to their singular power spectra.
3) Less well known are his "conditionally stationary" models from 1963-1967 which achieved 1/f noise through long-tailed waiting times
2014 Wroclaw Mandelbrot's Other Model of 1/f NoiseNick Watkins
1) Mandelbrot gave an invited talk discussing several of his models for 1/f noise processes, including fractional Brownian motion (fBm) and fractional Gaussian noise (fGn) which introduced the concept of long-range dependence.
2) However, he later emphasized that reducing 1/f noise solely to the property of self-similarity was an oversimplification. His other models, like fractional hyperbolic motion and multiplicative multifractal cascades, exhibited different visual properties.
3) One lesser known class was his "dustborne" models from 1965-1967, which involved renewal processes with heavy-tailed waiting times. These exhibited properties like ergodicity breaking and time-dependent power spectra
The document discusses different aspects and theories of time travel, including:
1) It explores Einstein's theory of general relativity which seems to allow for the possibility of backwards time travel if space-time can curve enough.
2) It addresses that going forward in time is relatively easy, while going backwards is much harder due to the challenges of significantly warping space-time.
3) The document discusses that time travel may be possible if there are differences in the flow of time between people, for example if one was able to travel at speeds close to the speed of light relative to others.
2014 OU Mandelbrot's eyes and 1/f noiseNick Watkins
The document discusses Benoit Mandelbrot's work on modeling wild fluctuations and long-range dependence that he observed in various real-world datasets. It describes how his initial attempts to explain these phenomena with heavy-tailed distributions and fractional Brownian motion led him to abstract the property of self-similarity in the spectral domain. The document also notes that Mandelbrot warned against over-interpreting any single property and advocated using our eyes alongside formulas to fully understand complexity.
This article aims to present possible strategies for humanity to seek its survival with the end of the Universe in which we live. Research on the fate of our Universe, on the existence or not of multiverse or parallel universes and on the development of the final theory or theory of everything, that is, of the theory of the unified field, are important questions to elucidate in order to point out possible strategies for humanity seeks its survival with the end of the Universe in which we live.
The document discusses various concepts and theories related to time travel. It begins by defining time travel as moving between different points in time analogous to moving between different points in space, potentially using a time machine. It then discusses Einstein's theories of special and general relativity which established that time is relative and affected by speed and gravity. The document considers some potential ways to achieve time travel, such as moving faster than light, traveling through wormholes or black holes, but also notes significant challenges like paradoxes. It provides examples of depictions of time travel in science fiction films to help explain these complex theoretical physics concepts.
This PowerPoint discusses different theories and concepts related to time travel. It begins by defining time travel as moving between different points in time analogous to moving between different points in space, either sending objects backwards or forwards without experiencing the intervening time. It notes that general and special relativity suggest time travel could be possible through suitable geometries of space-time or specific types of motion. It also discusses wormholes and closed time-like curves as hypothetical concepts permitted by general relativity that could allow time travel. Finally, it briefly discusses some potential futures a time traveler might encounter, such as robots, cyborgs, flying cars, and aliens.
Can the vacuum be engineered for space flight applications by h.e.puthoffPublicLeaker
1) The document discusses theories and experiments regarding zero-point energy (ZPE) in the quantum vacuum and possibilities for engineering the vacuum for applications like space propulsion.
2) Several approaches are proposed for tapping into ZPE as an energy source, including exploiting the Casimir effect and sonoluminescence. Experiments on these approaches are ongoing.
3) The author proposes that vacuum fluctuations may be the source of fundamental forces like gravity and inertia, and that engineering the vacuum could therefore influence these forces with implications for space travel like reducing spacecraft mass.
The network of filaments with embedded clusters surrounding voids, which has been seen in maps derived from
redshift surveys and reproduced in simulations, has been referred to as the cosmic web. A complementary
description is provided by considering the shear in the velocity field of galaxies. The eigenvalues of the shear
provide information regarding whether or not a region is collapsing in three dimensions, which is the condition for
a knot, expanding in three dimensions, which is the condition for a void, or in the intermediate condition of a
filament or sheet. The structures that are quantitatively defined by the eigenvalues can be approximated by isocontours
that provide a visual representation of the cosmic velocity (V) web. The current application is based on
radial peculiar velocities from the Cosmicflows-2 collection of distances. The three-dimensional velocity field is
constructed using the Wiener filter methodology in the linear approximation. Eigenvalues of the velocity shear are
calculated at each point on a grid. Here, knots and filaments are visualized across a local domain of
diameter ~0.1c
This presentation proposes a novel nature-inspired algorithm called Multi-Verse Optimizer (MVO). The main inspirations of this algorithm are based on three concepts in cosmology: white hole, black hole, and wormhole.
This presentation is based on https://link.springer.com/article/10.1007%2Fs00521-015-1870-7
It proposes a novel nature-inspired algorithm called Multi-Verse Optimizer (MVO). The main inspirations of this algorithm are based on three concepts in cosmology: white hole, black hole, and wormhole. The mathematical models of these three concepts are developed to perform exploration, exploitation, and local search, respectively. MVO is compared with four well known algorithms: Grey Wolf Optimizer, Particle Swarm Optimization, Genetic Algorithm, and Gravitational Search Algorithm. The results prove that the proposed algorithm is able to provide very competitive results and outperforms the best algorithms in the literature on the majority of the test beds.
The document discusses the twin paradox of special relativity. It describes how one twin stays on Earth while the other travels to Alpha Centauri at 0.8 the speed of light and returns. When they reunite, the traveling twin is younger due to time dilation effects predicted by Einstein's theory of special relativity. The document uses vectors and an inner product defined on Minkowski spacetime to mathematically model the twins' trajectories and show that the traveling twin ages only 6 years while the Earth twin ages 10 years. It explains how special relativity introduces a new geometry where the shortest distance between points may not be a straight line.
Hi guys!!!
This is a presentation on the time travel.Many of us don't know about time travel, so here you can find the complete information regarding the time travel.
If you guys have any doubts then feel free to ask me in the comments section.
THANK YOU!!!!
A population of faint low surface brightness galaxies in the Perseus cluster ...Sérgio Sacani
We present the detection of 89 low surface brightness (LSB), and thus low stellar
density galaxy candidates in the Perseus cluster core, of the kind named ‘ultra-diffuse
galaxies’, with mean effective V-band surface brightnesses 24.8–27.1 mag arcsec−2
, total
V-band magnitudes −11.8 to −15.5 mag, and half-light radii 0.7–4.1 kpc. The candidates
have been identified in a deep mosaic covering 0.3 deg2
, based on wide-field
imaging data obtained with the William Herschel Telescope. We find that the LSB
galaxy population is depleted in the cluster centre and only very few LSB candidates
have half-light radii larger than 3 kpc. This appears consistent with an estimate of
their tidal radius, which does not reach beyond the stellar extent even if we assume
a high dark matter content (M/L = 100). In fact, three of our candidates seem to
be associated with tidal streams, which points to their current disruption. Given that
published data on faint LSB candidates in the Coma cluster – with its comparable central
density to Perseus – show the same dearth of large objects in the core region, we
conclude that these cannot survive the strong tides in the centres of massive clusters.
This document discusses the concept of time travel through various theories and possibilities. It explains that according to Einstein's theory of relativity, time is relative and can vary for different observers depending on speed. The document then outlines various hypothesized methods for time travel, such as wormholes, black holes, and time machines. It provides brief descriptions of wormholes and black holes as potential means for time travel. The document also discusses how time dilation effects from traveling close to the speed of light could allow for time travel into the future.
Dark matter makes up about 5 times as much of the matter in the universe as regular matter, though its composition is unknown. It interacts very weakly and was first discovered through its gravitational effects on galaxy rotations. Dark energy makes up about 75% of the universe and is causing its accelerating expansion, though the source is a mystery and quantum effects predict a much larger value. String theory landscape ideas may help explain the observed size of dark energy through vacuum selection in a complicated potential.
Dark matter is an invisible phenomenon that acts on visible matter through gravity. It accounts for 6 times more mass in the universe than normal matter. Fritz Zwicky discovered evidence of "invisible matter" in galaxies in 1933 while Vera Rubin provided further evidence in the 1970s, though they were initially disregarded. String theory may help explain dark matter through postulated supersymmetric particles. Dark energy is a hypothetical form that permeates space, causing accelerated expansion of the universe, and may account for most of its mass. It produces an opposite effect to gravity. String theory also provides several potential explanations for dark matter through concepts like supersymmetric particles, branes, and extra dimensions.
In this presentation, I am discussing about possibilities and Including various concepts and Theories related to Time Travel.
I HOPE YOU ALL WILL LIKE THIS PRESENTATION
This PowerPoint is one small part of the Matter, Energy, and the Environment Unit from www.sciencepowerpoint.com. This unit consists of a five part 3,500+ slide PowerPoint roadmap, 12 page bundled homework package, modified homework, detailed answer keys, 20 pages of unit notes for students who may require assistance, follow along worksheets, and many review games. The homework and lesson notes chronologically follow the PowerPoint slideshow. The answer keys and unit notes are great for support professionals. The activities and discussion questions in the slideshow are meaningful. The PowerPoint includes built-in instructions, visuals, and review questions. Also included are critical class notes (color coded red), project ideas, video links, and review games. This unit also includes four PowerPoint review games (110+ slides each with Answers), 38+ video links, lab handouts, activity sheets, rubrics, materials list, templates, guides, and much more. Also included is a 190 slide first day of school PowerPoint presentation.
Areas of Focus: Matter, Dark Matter, Elements and Compounds, States of Matter, Solids, Liquids, Gases, Plasma, Law Conservation of Matter, Physical Change, Chemical Change, Gas Laws, Charles Law, Avogadro's Law, Ideal Gas Law, Pascal's Law, Archimedes Principle, Buoyancy, Seven Forms of Energy, Nuclear Energy, Electromagnet Spectrum, Waves / Wavelengths, Light (Visible Light), Refraction, Diffraction, Lens, Convex / Concave, Radiation, Electricity, Lightning, Static Electricity, Magnetism, Coulomb's Law, Conductors, Insulators, Semi-conductors, AC and DC current, Amps, Watts, Resistance, Magnetism, Faraday's Law, Compass, Relativity, Einstein, and E=MC2, Energy, First Law of Thermodynamics, Second Law of Thermodynamics-Third Law of Thermodynamics, Industrial Processes, Environmental Studies, The 4 R's, Sustainability, Human Population Growth, Carrying Capacity, Green Design, Renewable Forms of Energy (The 11th Hour)
This unit aligns with the Next Generation Science Standards and with Common Core Standards for ELA and Literacy for Science and Technical Subjects. See preview for more information
If you have any questions please feel free to contact me. Thanks again and best wishes. Sincerely, Ryan Murphy M.Ed www.sciencepowerpoint@gmail.com
Teaching Duration = 4+ Weeks
a detail presentation on one of the most debated topics ever...The presentation features Einsteins,Stephen Hawkings views on time travel. possibilities and ways through travel through time are discussed in the presentation
This document summarizes an article that proposes an alternative explanation for dark energy and dark matter based on a modified theory of gravity. It begins by providing background on dark matter and dark energy in standard cosmology and the evidence that supports their existence. It then outlines the proposed alternative theory, which modifies Einstein's field equations by adding a function of the Ricci scalar. This introduces new curvature terms that could potentially drive accelerated expansion, providing an alternative to dark energy. The theory aims to match observations without requiring dark matter or energy, but reduces to general relativity in the solar system scale where it has been tightly tested.
Causality from outside Time
Alfred Driessen
Talk presented at the 21th International Interdisciplinary Seminar,
Science and Society: Defining what is human
Netherhall House, London, 5-1-2019
Content
Introduction
Time in Relativity
Time in Quantum Mechanics
Conclusions
Conclusions from this study:
There are causes beyond the realm of science,
- they are not observable by physical or scientific means
- the effects of these causes, however, are observable by physical and scientific means.
Physics is not complete.
The document discusses how recent scientific advancements are validating spiritual truths. It provides examples of physicists exploring concepts like parallel universes, quantum entanglement, and the fine-tuning of physical constants that allow for life. These ideas relate to spiritual concepts of consciousness not being dependent on the physical body and the possibility of an afterlife. The document argues that science appears to be "landing in the all-embracing arms of spirituality".
Recomendation system: Community Detection Based Recomendation System using Hy...Rajul Kukreja
The document discusses using community detection techniques on social networks to improve recommendation systems. It describes how finding communities of users with similar interests allows predicting what products or content those users may like. This helps address the "cold start" problem of having insufficient data for new users. The document outlines modeling the social network as a hypergraph and using a local community detection algorithm to identify communities, which are then used to make collaborative recommendations based on similarities between users.
2014 tromso generalised and fractional Langevin equations implications for en...Nick Watkins
The document discusses using stochastic energy balance models (EBMs) to study climate sensitivity over time. It raises three questions: 1) Can concepts from the Langevin equation and Generalized Langevin Equation be applied to EBMs with memory? 2) Can fluctuation-dissipation theorems provide insights? 3) Could a fractional stochastic EBM result from a power-law memory kernel, and would this be useful? Answering these questions could provide new approaches to modeling climate sensitivity using EBMs with different memory properties.
This document summarizes the history and development of the concept of market efficiency. It discusses early works in the 1900s that anticipated the idea, and key studies in the 1950s-60s that developed the random walk model and market efficiency theory. Major topics covered include event studies in the late 1960s that provided empirical evidence; analysis in the 1960s-70s of mutual funds and managers that supported efficient markets; and anomalies identified starting in the 1970s that challenged aspects of efficiency. The document concludes by noting the ongoing debate between the efficient market framework and behavioral theories to explain anomalies.
The network of filaments with embedded clusters surrounding voids, which has been seen in maps derived from
redshift surveys and reproduced in simulations, has been referred to as the cosmic web. A complementary
description is provided by considering the shear in the velocity field of galaxies. The eigenvalues of the shear
provide information regarding whether or not a region is collapsing in three dimensions, which is the condition for
a knot, expanding in three dimensions, which is the condition for a void, or in the intermediate condition of a
filament or sheet. The structures that are quantitatively defined by the eigenvalues can be approximated by isocontours
that provide a visual representation of the cosmic velocity (V) web. The current application is based on
radial peculiar velocities from the Cosmicflows-2 collection of distances. The three-dimensional velocity field is
constructed using the Wiener filter methodology in the linear approximation. Eigenvalues of the velocity shear are
calculated at each point on a grid. Here, knots and filaments are visualized across a local domain of
diameter ~0.1c
This presentation proposes a novel nature-inspired algorithm called Multi-Verse Optimizer (MVO). The main inspirations of this algorithm are based on three concepts in cosmology: white hole, black hole, and wormhole.
This presentation is based on https://link.springer.com/article/10.1007%2Fs00521-015-1870-7
It proposes a novel nature-inspired algorithm called Multi-Verse Optimizer (MVO). The main inspirations of this algorithm are based on three concepts in cosmology: white hole, black hole, and wormhole. The mathematical models of these three concepts are developed to perform exploration, exploitation, and local search, respectively. MVO is compared with four well known algorithms: Grey Wolf Optimizer, Particle Swarm Optimization, Genetic Algorithm, and Gravitational Search Algorithm. The results prove that the proposed algorithm is able to provide very competitive results and outperforms the best algorithms in the literature on the majority of the test beds.
The document discusses the twin paradox of special relativity. It describes how one twin stays on Earth while the other travels to Alpha Centauri at 0.8 the speed of light and returns. When they reunite, the traveling twin is younger due to time dilation effects predicted by Einstein's theory of special relativity. The document uses vectors and an inner product defined on Minkowski spacetime to mathematically model the twins' trajectories and show that the traveling twin ages only 6 years while the Earth twin ages 10 years. It explains how special relativity introduces a new geometry where the shortest distance between points may not be a straight line.
Hi guys!!!
This is a presentation on the time travel.Many of us don't know about time travel, so here you can find the complete information regarding the time travel.
If you guys have any doubts then feel free to ask me in the comments section.
THANK YOU!!!!
A population of faint low surface brightness galaxies in the Perseus cluster ...Sérgio Sacani
We present the detection of 89 low surface brightness (LSB), and thus low stellar
density galaxy candidates in the Perseus cluster core, of the kind named ‘ultra-diffuse
galaxies’, with mean effective V-band surface brightnesses 24.8–27.1 mag arcsec−2
, total
V-band magnitudes −11.8 to −15.5 mag, and half-light radii 0.7–4.1 kpc. The candidates
have been identified in a deep mosaic covering 0.3 deg2
, based on wide-field
imaging data obtained with the William Herschel Telescope. We find that the LSB
galaxy population is depleted in the cluster centre and only very few LSB candidates
have half-light radii larger than 3 kpc. This appears consistent with an estimate of
their tidal radius, which does not reach beyond the stellar extent even if we assume
a high dark matter content (M/L = 100). In fact, three of our candidates seem to
be associated with tidal streams, which points to their current disruption. Given that
published data on faint LSB candidates in the Coma cluster – with its comparable central
density to Perseus – show the same dearth of large objects in the core region, we
conclude that these cannot survive the strong tides in the centres of massive clusters.
This document discusses the concept of time travel through various theories and possibilities. It explains that according to Einstein's theory of relativity, time is relative and can vary for different observers depending on speed. The document then outlines various hypothesized methods for time travel, such as wormholes, black holes, and time machines. It provides brief descriptions of wormholes and black holes as potential means for time travel. The document also discusses how time dilation effects from traveling close to the speed of light could allow for time travel into the future.
Dark matter makes up about 5 times as much of the matter in the universe as regular matter, though its composition is unknown. It interacts very weakly and was first discovered through its gravitational effects on galaxy rotations. Dark energy makes up about 75% of the universe and is causing its accelerating expansion, though the source is a mystery and quantum effects predict a much larger value. String theory landscape ideas may help explain the observed size of dark energy through vacuum selection in a complicated potential.
Dark matter is an invisible phenomenon that acts on visible matter through gravity. It accounts for 6 times more mass in the universe than normal matter. Fritz Zwicky discovered evidence of "invisible matter" in galaxies in 1933 while Vera Rubin provided further evidence in the 1970s, though they were initially disregarded. String theory may help explain dark matter through postulated supersymmetric particles. Dark energy is a hypothetical form that permeates space, causing accelerated expansion of the universe, and may account for most of its mass. It produces an opposite effect to gravity. String theory also provides several potential explanations for dark matter through concepts like supersymmetric particles, branes, and extra dimensions.
In this presentation, I am discussing about possibilities and Including various concepts and Theories related to Time Travel.
I HOPE YOU ALL WILL LIKE THIS PRESENTATION
This PowerPoint is one small part of the Matter, Energy, and the Environment Unit from www.sciencepowerpoint.com. This unit consists of a five part 3,500+ slide PowerPoint roadmap, 12 page bundled homework package, modified homework, detailed answer keys, 20 pages of unit notes for students who may require assistance, follow along worksheets, and many review games. The homework and lesson notes chronologically follow the PowerPoint slideshow. The answer keys and unit notes are great for support professionals. The activities and discussion questions in the slideshow are meaningful. The PowerPoint includes built-in instructions, visuals, and review questions. Also included are critical class notes (color coded red), project ideas, video links, and review games. This unit also includes four PowerPoint review games (110+ slides each with Answers), 38+ video links, lab handouts, activity sheets, rubrics, materials list, templates, guides, and much more. Also included is a 190 slide first day of school PowerPoint presentation.
Areas of Focus: Matter, Dark Matter, Elements and Compounds, States of Matter, Solids, Liquids, Gases, Plasma, Law Conservation of Matter, Physical Change, Chemical Change, Gas Laws, Charles Law, Avogadro's Law, Ideal Gas Law, Pascal's Law, Archimedes Principle, Buoyancy, Seven Forms of Energy, Nuclear Energy, Electromagnet Spectrum, Waves / Wavelengths, Light (Visible Light), Refraction, Diffraction, Lens, Convex / Concave, Radiation, Electricity, Lightning, Static Electricity, Magnetism, Coulomb's Law, Conductors, Insulators, Semi-conductors, AC and DC current, Amps, Watts, Resistance, Magnetism, Faraday's Law, Compass, Relativity, Einstein, and E=MC2, Energy, First Law of Thermodynamics, Second Law of Thermodynamics-Third Law of Thermodynamics, Industrial Processes, Environmental Studies, The 4 R's, Sustainability, Human Population Growth, Carrying Capacity, Green Design, Renewable Forms of Energy (The 11th Hour)
This unit aligns with the Next Generation Science Standards and with Common Core Standards for ELA and Literacy for Science and Technical Subjects. See preview for more information
If you have any questions please feel free to contact me. Thanks again and best wishes. Sincerely, Ryan Murphy M.Ed www.sciencepowerpoint@gmail.com
Teaching Duration = 4+ Weeks
a detail presentation on one of the most debated topics ever...The presentation features Einsteins,Stephen Hawkings views on time travel. possibilities and ways through travel through time are discussed in the presentation
This document summarizes an article that proposes an alternative explanation for dark energy and dark matter based on a modified theory of gravity. It begins by providing background on dark matter and dark energy in standard cosmology and the evidence that supports their existence. It then outlines the proposed alternative theory, which modifies Einstein's field equations by adding a function of the Ricci scalar. This introduces new curvature terms that could potentially drive accelerated expansion, providing an alternative to dark energy. The theory aims to match observations without requiring dark matter or energy, but reduces to general relativity in the solar system scale where it has been tightly tested.
Causality from outside Time
Alfred Driessen
Talk presented at the 21th International Interdisciplinary Seminar,
Science and Society: Defining what is human
Netherhall House, London, 5-1-2019
Content
Introduction
Time in Relativity
Time in Quantum Mechanics
Conclusions
Conclusions from this study:
There are causes beyond the realm of science,
- they are not observable by physical or scientific means
- the effects of these causes, however, are observable by physical and scientific means.
Physics is not complete.
The document discusses how recent scientific advancements are validating spiritual truths. It provides examples of physicists exploring concepts like parallel universes, quantum entanglement, and the fine-tuning of physical constants that allow for life. These ideas relate to spiritual concepts of consciousness not being dependent on the physical body and the possibility of an afterlife. The document argues that science appears to be "landing in the all-embracing arms of spirituality".
Recomendation system: Community Detection Based Recomendation System using Hy...Rajul Kukreja
The document discusses using community detection techniques on social networks to improve recommendation systems. It describes how finding communities of users with similar interests allows predicting what products or content those users may like. This helps address the "cold start" problem of having insufficient data for new users. The document outlines modeling the social network as a hypergraph and using a local community detection algorithm to identify communities, which are then used to make collaborative recommendations based on similarities between users.
2014 tromso generalised and fractional Langevin equations implications for en...Nick Watkins
The document discusses using stochastic energy balance models (EBMs) to study climate sensitivity over time. It raises three questions: 1) Can concepts from the Langevin equation and Generalized Langevin Equation be applied to EBMs with memory? 2) Can fluctuation-dissipation theorems provide insights? 3) Could a fractional stochastic EBM result from a power-law memory kernel, and would this be useful? Answering these questions could provide new approaches to modeling climate sensitivity using EBMs with different memory properties.
This document summarizes the history and development of the concept of market efficiency. It discusses early works in the 1900s that anticipated the idea, and key studies in the 1950s-60s that developed the random walk model and market efficiency theory. Major topics covered include event studies in the late 1960s that provided empirical evidence; analysis in the 1960s-70s of mutual funds and managers that supported efficient markets; and anomalies identified starting in the 1970s that challenged aspects of efficiency. The document concludes by noting the ongoing debate between the efficient market framework and behavioral theories to explain anomalies.
This document summarizes key points from the book "A Random Walk Down Wall Street" by Burton G. Malkiel. The book is divided into four parts that discuss the history of stock prices, how professional investors pick stocks, new investment theories and technology, and practical investment advice. It covers various investment theories like the firm foundation theory and the castles in the air theory. It also discusses different analysis methods used by professionals like technical analysis and fundamental analysis. The document emphasizes the importance of diversification and provides basic investment advice like having insurance, investing in tax-advantaged accounts, including bonds in a portfolio, owning a home, keeping commissions low, and adjusting investment strategies based on investment goals and time horizons.
This document summarizes a study that tested the random walk hypothesis on the Karachi Stock Exchange 100 Index from 1996 to 2006. The random walk hypothesis states that stock prices fully reflect all available information and follow a random pattern, making them unpredictable. The study found no significant differences in average monthly or daily returns, supporting the hypothesis that the KSE follows a random walk pattern. Therefore, past stock prices and returns cannot be used to predict future movements. This finding indicates the KSE behaves as an efficient market.
Presented "Random Walk on Graphs" in the reading group for Knoesis. Specifically for Recommendation Context.
Referred: Purnamrita Sarkar, Random Walks on Graphs: An Overview
Random Walk Theory: 'Sistemi di grid automatizzati per Metatrader 4'Stefano Gianti
Introduzione ad un sistema il cui obiettivo è quello di seguire il "movimento casuale dei prezzi". Questo è il primo webinar base, seguirà un approfondimento operativo a settimana. "* Che cos'è un sistema ""a griglia"" e perché si chiama cosi?
- Cosa si intende per ""random walk""?
- Presentazione completa del sistema di trading
- Illustrazione di ogni singolo parametro dell'EA
- Domande e casi pratici
- Paragone rispetto al Supertrend
- Su quali strumenti e timeframe fare trading con questa strategia?
Relatori: Fabio PACCHIONI & Stefano GIANTI
Samza: Real-time Stream Processing at LinkedInC4Media
Video and slides synchronized, mp3 and slide download available at URL http://bit.ly/1eGbVJv.
Chris Riccomini discusses: Samza's feature set, how Samza integrates with YARN and Kafka, how it's used at LinkedIn, and what's next on the roadmap. Filmed at qconsf.com.
Chris Riccomini is a Staff Software Engineer at LinkedIn, where he's is currently working as a committer and PMC member for Apache Samza. He's been involved in a wide range of projects at LinkedIn, including, "People You May Know", REST.li, Hadoop, engineering tooling, and OLAP systems. Prior to LinkedIn, he worked on data visualization and fraud modeling at PayPal.
This document discusses clustering random walk time series. It introduces the concept of clustering and discusses challenges in clustering time series, such as how to define a distance between dependent random variables. It proposes using the copula transform and empirical copula transform to map time series to uniform distributions before calculating distances. The hierarchical block model for nested data partitions is presented. Experimental results show the proposed distances perform well in recovering the nested partitions on both synthetic hierarchical block model data and real credit default swap time series data. Consistency of clustering algorithms is defined in relation to recovering the hierarchical block model partitions.
Building Real-time Data Products at LinkedIn with Apache SamzaTrieu Nguyen
The world is going real-time. MapReduce, SQL-on-Hadoop and similar batch processing tools are fine for analyzing and processing data after the fact — but sometimes you need to process data continuously as it comes in, and react to it within a few seconds or less. How do you do that at Hadoop scale?
Apache Samza is an open source stream processing framework designed to solve these kinds of problems. It is built upon YARN/Hadoop 2.0 and Apache Kafka. You can think of Samza as a real-time, continuously running version of MapReduce.
Samza has some unique features that make it powerful. It provides high performance for stateful processing jobs, including aggregation and joins between many input streams. It is designed to support an ecosystem of many different jobs written by different teams, and it isolates them from each other, so that one badly behaved job can’t affect the others.
The document discusses tests performed to analyze random walk theory (RWT). RWT states that future stock prices cannot be predicted from past prices. Simulation tests, conducted by Harry Roberts, generated random stock price graphs to examine RWT. Serial correlation tests, performed by Moore in 1964, analyzed correlations between weekly stock price changes. Filter tests established buy and sell points at certain percentage thresholds above or below original prices. Run tests counted consecutive price increases or decreases to assess randomness.
The document discusses the random walk theory, which states that stock price movements cannot be predicted because they follow a random path rather than any predictable patterns. It originated in the 1900s and was popularized in a 1973 book. The random walk theory says past stock performance does not indicate future performance and prices reflect all available information. However, some studies have found evidence of predictability based on factors like earnings. The implications are that market timing is difficult and outperforming the market through analysis alone may involve some luck.
Independent of the source of data, the integration of event streams into an Enterprise Architecture gets more and more important in the world of sensors, social media streams and Internet of Things. Events have to be accepted quickly and reliably, they have to be distributed and analysed, often with many consumers or systems interested in all or part of the events. Storing such huge event streams into HDFS or a NoSQL datastore is feasible and not such a challenge anymore. But if you want to be able to react fast, with minimal latency, you can not afford to first store the data and doing the analysis/analytics later. You have to be able to include part of your analytics right after you consume the event streams. Products for doing event processing, such as Oracle Event Processing or Esper, are avaialble for quite a long time and also used to be called Complex Event Processing (CEP). In the last 3 years, another family of products appeared, mostly out of the Big Data Technology space, called Stream Processing or Streaming Analytics. These are mostly open source products/frameworks such as Apache Storm, Spark Streaming, Apache Samza as well as supporting infrastructures such as Apache Kafka. In this talk I will present the theoretical foundations for Event and Stream Processing and present what differences you might find between the more traditional CEP and the more modern Stream Processing solutions and show that a combination will bring the most value.
Samza at LinkedIn: Taking Stream Processing to the Next LevelMartin Kleppmann
Slides from my talk at Berlin Buzzwords, 27 May 2014. Unfortunately Slideshare has screwed up the fonts. See https://speakerdeck.com/ept/samza-at-linkedin-taking-stream-processing-to-the-next-level for a version of the deck with correct fonts.
Stream processing is an essential part of real-time data systems, such as news feeds, live search indexes, real-time analytics, metrics and monitoring. But writing stream processes is still hard, especially when you're dealing with so much data that you have to distribute it across multiple machines. How can you keep the system running smoothly, even when machines fail and bugs occur?
Apache Samza is a new framework for writing scalable stream processing jobs. Like Hadoop and MapReduce for batch processing, it takes care of the hard parts of running your message-processing code on a distributed infrastructure, so that you can concentrate on writing your application using simple APIs. It is in production use at LinkedIn.
This talk will introduce Samza, and show how to use it to solve a range of different problems. Samza has some unique features that make it especially interesting for large deployments, and in this talk we will dig into how they work under the hood. In particular:
• Samza is built to support many different jobs written by different teams. Isolation between jobs ensures that a single badly behaved job doesn't affect other jobs. It is robust by design.
• Samza can handle jobs that require large amounts of state, for example joining multiple streams, augmenting a stream with data from a database, or aggregating data over long time windows. This makes it a very powerful tool for applications.
Agenda:
• Background for the development: From commodity
to experience
• Indirect use of experiences: Experience as value
adding
• Experience process
• Selling pure experiences: Using the experience realm
model
• How to develop experiences
• Creating the experience settings
ML and Data Science at Uber - GITPro talk 2017Sudhir Tonse
This document summarizes a presentation given by Sudhir Tonse, an engineering lead at Uber, about machine learning and data science at Uber. The summary discusses how Uber uses machine learning for problems like mapping, fraud detection, recommendations, marketplace optimization, and forecasting. It also provides an overview of Uber's data processing pipeline and tools used, including challenges around building spatiotemporal models at Uber's massive scale.
Customer Event Hub - the modern Customer 360° viewGuido Schmutz
Today, companies are using various channels to communicate with their customers. As a consequence, a lot of data is created, more and more also outside of the traditional IT infrastructure of an enterprise. This data often does not have a common format and they are continuously created with ever increasing volume. With Internet of Things (IoT) and their sensors, the volume as well as the velocity of data just gets more extreme.
To achieve a complete and consistent view of a customer, all these customer-related information has to be included in a 360 degree view in a real-time or near-real-time fashion. By that, the Customer Hub will become the Customer Event Hub. It constantly shows the actual view of a customer over all his interaction channels and provides an enterprise the basis for a substantial and effective customer relation.
In this presentation the value of such a platform is shown and how it can be implemented.
Real-time Streaming Analytics: Business Value, Use Cases and Architectural Co...Impetus Technologies
Impetus webcast ‘Real-time Streaming Analytics: Business Value, Use Cases and Architectural Considerations’ available at http://bit.ly/1i6OrwR
The webinar talks about-
• How business value is preserved and enhanced using Real-time Streaming Analytics with numerous use-cases in different industry verticals
• Technical considerations for IT leaders and implementation teams looking to integrate Real-time Streaming Analytics into enterprise architecture roadmap
• Recommendations for making Real-time Streaming Analytics – real – in your enterprise
• Impetus StreamAnalytix – an enterprise ready platform for Real-time Streaming Analytics
Slides of QCon London 2016 talk. How stream processing is used within the Uber's Marketplace system to solve a wide range problems, including but not limited to realtime indexing and querying of geospatial time series, aggregation and computing of streaming data, and extracting patterns from data streams. In addition, it will touch upon various TimeSeries analysis and predictions. The underlying systems utilize many open source technologies such as Apache Kafka, Samza and Spark streaming.
LSE 2012 Extremes, Bursts and Mandelbrot's Eyes ... and Five Ways to Mis-esti...Nick Watkins
This document discusses Mandelbrot's work on non-Gaussian stochastic processes and their implications for estimating risk and extremes. It contains the following key points:
1) Mandelbrot made three "giant leaps" in the 1960s-70s by proposing alpha-stable models to describe heavy-tailed fluctuations, applying self-similarity to model long-range dependence, and developing multifractal cascades.
2) If natural phenomena exhibit heavy tails and long memory, but models don't account for this, it can lead to underestimating risk and extremes. Mandelbrot's fractional stable motion combines heavy tails and long-range dependence.
3) Events that are rare according to short
Franz 2017 uiuc cirss non unitary syntheses of systematic knowledgetaxonbytes
Invited Presentation given at the University of Illinois Urbana Champaign iSchool, Center for Informatics Research in Science and Scholarship, CIRSS Seminar, Friday, February 17, 2017.
Class Of Forensic And Investigative SciencesLisa Kennedy
- The climate about 10,000 years ago was very different from the present climate, as it was much cooler globally during the last glacial period which ended around 10,000-12,000 years ago.
- Climate archives provide evidence that the Earth has cycled between cold and warm periods and is currently in an interglacial warm period with rising sea levels.
- Tree rings, ice cores, corals, and lake sediments are climate archives that can be studied to learn about past climates over the last 10,000 years.
STONE AGE CULTURE AND DIFFUSION IN ANNEALED RANDOM MEDIAijrap
Symbolic and technological complexity of human artifacts increased drastically around 45,000 years ago.
Powell, Shennan and Thomas (2009) explained it using a computer simulation of a demographic model
through an increase of the population density. We have simplified the computer demographic model to be
similar to standard physics models (percolation, random walks) for a large square lattice. Demography is a
major determinant in the maintenance of cultural complexity and its variation in regional subpopulation
density and/or migratory activity results in spatial structuring of cultural skill accumulation. Computer
simulations have been used to facilitate information spread by random walkers over dozens of distances
between human bands (extended families) of stone-age humans, distributed randomly on a large square
lattice such that each lattice site is randomly occupied with probability p and empty with probability 1−p,
and random walkers move among the occupied sites only.
In this paper we allow also these bands to move randomly on the lattice. This improvement has been done by
letting the communities perform slower random walks on the lattice such that no sharp percolation threshold
exists for the random walks of the walkers within groups of occupied neighboring sites..
Stone Age Culture And Diffusion In Annealed Random Mediaijrap
Symbolic and technological complexity of human artifacts increased drastically around 45,000 years ago.
Powell, Shennan and Thomas (2009) explained it using a computer simulation of a demographic model
through an increase of the population density. We have simplified the computer demographic model to be
similar to standard physics models (percolation, random walks) for a large square lattice. Demography is a
major determinant in the maintenance of cultural complexity and its variation in regional subpopulation
density and/or migratory activity results in spatial structuring of cultural skill accumulation. Computer
simulations have been used to facilitate information spread by random walkers over dozens of distances
between human bands (extended families) of stone-age humans, distributed randomly on a large square
lattice such that each lattice site is randomly occupied with probability p and empty with probability 1−p,
and random walkers move among the occupied sites only.
In this paper we allow also these bands to move randomly on the lattice. This improvement has been done by
letting the communities perform slower random walks on the lattice such that no sharp percolation threshold
exists for the random walks of the walkers within groups of occupied neighboring sites
The document summarizes a study of the near-contact-line dynamics of evaporating sessile drops containing bacteria. As the drop evaporates, an internal flow develops that transports bacteria outward and concentrates them near the contact line, where experiments show they form periodic jets. The study develops a theoretical model and numerical simulation of the averaged flow properties and bacteria behavior. Initial 1D simulations show bacteria transitioning from isotropic to aligned with flow near the edge, and bacteria density peaking near the edge matching experiments. Future 2D simulations aim to reproduce the periodic jet pattern observed.
Animal Farm Essay | PDF. Animal Farm Essay - GCSE English - Marked by Teachers.com. Animal Farm essay.doc. 34+ Animal Farm Essay Examples Full - Essay. Animal farm essay 1 .docx - 1 Analysis Essay Animal Farm Allegory In .... Animal Farm Study Guide (essay question options). Essay on Animal Farm By George Orwell - GCSE English - Marked by .... GCSE English Literature A* model essay - Animal Farm and 1984 .... Animal Farm Essay | PDF | Muammar Gaddafi | Political Theories. Descriptive Essay: Animal farm analysis essay. Animal Farm. - GCSE English - Marked by Teachers.com. Animal Farm - GCSE English - Marked by Teachers.com. Animal Farm Novel Essay. Animal Farm Essay - George Orwell’s Animal Farm, published in 1945 .... Animal Farm Essay | Essay on Animal Farm for Students and Children in .... Essay on Animal Farm by George Orwell - GCSE English - Marked by .... Animal essay. Animal farm - GCSE English - Marked by Teachers.com. Animal Farm Essay 1 | Psychology & Cognitive Science. Animal farm: - GCSE English - Marked by Teachers.com.
This dissertation extends the Time-Spectral method to overset flow solvers to simulate periodic flows. The Time-Spectral method transforms the time-dependent governing equations into a steady set by expanding the temporal variation at each point as a Fourier series. For overset grids with relative motion, some nodes are dynamically removed from the domain. The dissertation develops a hybrid Time-Spectral method that expands the temporal variation at these nodes in an alternative manner. Numerical experiments are presented validating the hybrid method, including 2D oscillating airfoils and a 3D simulation of a tiltrotor in hover and forward flight.
Presentation at Kuwait Institute for Scientific Research Amro Elfeki
This is a presentation delivered to the KISR (Kuwait Institute for Scientific Research). The presentation showing research activity, university education and consultation as a society services..
Interpreting ‘tree space’ in the context of very large empirical datasetsJoe Parker
Seminar presented at the Maths Department, University of Portsmouth, 19th November 2014
Evolutionary biologists represent actual or hypothesised evolutionary relations between living organisms using phylogenies, directed bifurcating graphs (trees) that describe evolutionary processes in terms of speciation or splitting events (nodes) and elapsed evolutionary time or distance (edges). Molecular evolution itself is largely dominated by mutations in DNA sequences, a stochastic process. Traditionally, probabilistic models of molecular evolution and phylogenies are fitted to DNA sequence data by maximum likelihood on the assumption that a single simple phylogeny will serve to approximate the evolution of a majority of DNA positions in the dataset. However modern studies now routinely sample several orders of magnitude more DNA positions, and this assumption no longer holds. Unfortunately, our conception of ‘tree space’ - a notional multidimensional surface containing all possible phylogenies - is extremely imprecise, and similarly techniques to model phylogeny model fitting in very large datasets are limited. I will show the background to this field and present some of the challenges arising from the present limited analytical framework.
Scientists hypothesized that they could estimate the duration of mass extinction events by quantifying the amount of the element iridium found in a thin layer of clay between rock strata from the late Cretaceous period and early Cenozoic era. This thin layer of clay is found frequently between the final layer of Cretaceous rock and the initial layer of Cenozoic rock, representing an abrupt transition where many plant and animal species cease to appear in the fossil record. Scientists proposed measuring the deposition time of this clay layer by counting the quantity of iridium, as iridium abundances have been used to correlate strata and geological timelines at extinction boundaries.
1. The document discusses the anatomical evolution of the pelvis in primates and humans from quadrupedal to bipedal locomotion.
2. Key anatomical adaptations that enabled human bipedalism include the development of a specialized human foot, a long femoral neck, and a pelvis optimized for weight bearing stability over mobility.
3. The human pelvis and hip joint are uniquely adapted among primates for an upright, bipedal stance and gait under the compressive forces of standing, with implications for conditions like hip osteoarthritis.
This Power Point was designed to accompany a Web Quest titled The Geologic History of New York State. It is designed as an introduction to Geologic Time and has an accompanying worksheet that can be downloaded from the Web Quest.
Ecomorphological diversity of Mesozoic mammalsGareth Coleman
This document is a literature review by Gareth Coleman analyzing the ecomorphological diversity of Mesozoic mammals. It discusses past views of early mammals as small and generalized versus modern evidence from new fossils and analytical techniques like finite element analysis and dental microwear analysis showing successive waves of ecomorphological diversification in early mammals. The review examines morphological and analytical methods used to determine the diets and ecological niches of fossil mammals, and how current evidence indicates much higher levels of diversity and specialization among Mesozoic mammalian lineages than previously believed.
This document discusses human evolution and provides learning objectives related to dating methods, major anatomical features of primates, and trends in hominid evolution. It describes how radioactive dating of rocks and fossils can determine ages and discusses isotopes like carbon-14, potassium-40, and uranium that are used. Key anatomical primate features include grasping limbs and stereoscopic vision. Major hominid lineages discussed include Ardipithecus, Australopithecus, and various Homo species. The incompleteness of the fossil record results in uncertainties about the exact relationships between hominid species.
The document discusses Albert Einstein's Special Theory of Relativity, which established that the laws of physics are the same in all inertial reference frames and that the speed of light in a vacuum is constant. It explains key concepts such as length contraction, time dilation, and mass-energy equivalence that arise from these postulates. Examples are provided to illustrate how observations of phenomena can change depending on the reference frame of the observer.
MY RESEARCH PLAN By Yvette RomeroCompletedAssignmentDat.docxgemaherd
MY RESEARCH PLAN
By Yvette Romero
Completed?
Assignment
Dates
Research Proposal & Plan
9/25/18
Conference Day @ 9:30 A.M
DUE: 9/27/18
Annotated Bibliography (5)
Annotated Bibliography (5)
Annotated Bibliography (5)
Submit Annotated Bibliography
10/12/18
10/14/18
10/17/18
DUE: 10/19/18
Research Report
10/21/18
DUE: 10/23/18
Research Writing & Note Cards
10/28/18
DUE: 10/30/18
Outline
10/31/18
DUE: 11/1/18
1st draft (pp. 6)
11/3/18
DUE: 11/6/18
2nd draft (pp. 8)
11/5/18
DUE: 11/8/18
3rd draft (Whole essay- pp.8-12)
11/9/18
DUE: 11/13/18
4th draft (Final Essay) & Work Cited
11/11/18
DUE: 11/15/18
Portfolio Project
11/18/18
DUE: 11/20/18
E-portfolio
11/27/18
Research Paper & Research portfolio
11/29/18
Presentations
11/29/18
1
2
Introduction
Evolution is the process that involves the change in organisms over a period of time as a result of changes in hereditable, physical or behavioral characters. The truth behind Evolution emphasizes the solid pieces of evidence that verifies mostly evolution natural selection to be a fact. Putting together and explaining the latest ideas and discoveries from many disparate areas of the modernized science Jerry A. Coyne leaves us with an open mind in his book of why evolution is true in any doubt about the truth and the beauty of evolution.
Chapter One: What is Evolution
Learning models in the evolution theories include various theories that explain more about the evolution and existence of many living things on the planet earth. These theories include cell theories, relativity theory, evolution theory (Winther, 2015), the theory of plate tectonics and atomic theory. Evolution shows us more about us in the whole extraordinary and the great array of life. It brings us together with every living thing in the earth today and with long-dead creatures and myriads whereby it provides us with the true accounts of our origins hence replacing thousands of year’s myths that existed and satisfied us.
According to Darwin’s theory of Evolution, it states that the whole of life was as a result of evolution (Winther, 2015). The operation was then later driven by Natural selection which happens to be the most valid theory supported by evidence from a wide variety of scientific fields like geology, genetics, paleontology, and developmental scientists and it’s sometimes described as the survival of the fittest. However, it is equally thought to erode morality.
Various shreds of evidence have been found that supports the evolution theory, for instance, the study on human evolution that involved a study on 1,900 students published online in the month of October 2017 in the journal Personality and individual differences found that many people may have a problem in finding a mate because of the rapidly changing social technological advances that are faster growing than human whereby one or two individuals face considerable difficulties when mating (Winther, 2015). Also, the story of the origin of whale.
1. The document presents a simulation model that incorporates physical dimensions and constraints of objects moving through a navigation channel in a port system.
2. The model considers attributes like length, width, and security gaps between vessels to accurately model constraints on simultaneous vessel movements in the channel.
3. When applied to a case study of a major port in Latin America, the model that incorporated physical objects was validated against real data and found to have only a 0.45% deviation, supporting analysis of port operations and design.
This document summarizes a presentation about the history and applications of quaternions. It begins with quotes from Jean Piaget about the importance of mathematics in understanding knowledge development. It then provides background on quaternions, including their creation in 1843, rise and fall in popularity, and recent resurgence. Applications discussed include aerospace guidance, computer graphics, signal processing, bio-logging, and modeling molecular docking. The document argues quaternions are well-suited for tasks involving rotation, orientation, viewpoint shifting, and control processes.
Similar to A Random Walk Through Search Research (20)
2014 AGU Balancing fact and formula in complex sytems: the example of 1/f noiseNick Watkins
This document summarizes a talk given by Nick Watkins on distinguishing between the Hurst effect, 1/f spectra, and long range dependence (LRD) often conflated in time series analysis. It discusses how the Hurst effect refers to anomalous growth of the range over time, 1/f refers to a singularity in the Fourier spectrum, and LRD describes long memory seen in stationary processes with 1/f spectra. Mandelbrot originally showed the Hurst effect could be explained by fractional Gaussian noise exhibiting LRD. The document cautions against assuming stationarity and reviews alternative non-stationary models proposed by Mandelbrot to explain 1/f spectra without LRD.
IMA 2013 Bunched Black Swans at the British Antarctic SurveyNick Watkins
- THE WHAT: The speaker will discuss "bunched black swans", which are long range correlated, wild events. Specifically, the speaker will discuss "bursts" where the time series exceeds a threshold.
- THE WHY: Scientists studying climate, space weather, and finance care about bursts. The speaker will provide examples of why this is relevant to the British Antarctic Survey (BAS) and beyond.
- THE HOW: The speaker will discuss how they have modeled one class of "routinely extreme" burst problems using an approach building on Mandelbrot's work, involving fractional stable models.
Cambridge 2014 Complexity, tails and trendsNick Watkins
This document discusses two types of complexity that can affect trend detection in time series data: long range dependence and heavy tails.
Long range dependence, if present in a system, implies the presence of low frequency "slow" fluctuations that can complicate trend detection. Heavy tails in a probability distribution are a source of "wild" fluctuations due to more frequent extreme events.
The document reviews several examples of long range dependence and heavy tails observed in real-world datasets like financial data and space weather data. Statistical models like linear fractional stable motion (LFSM) and autoregressive fractionally integrated moving average (ARFIMA) processes are discussed for modeling systems with both properties. Better statistical inference methods are also needed to distinguish true
Dresden 2014 A tour of some fractional models and the physics behind themNick Watkins
This document provides a summary of fractional models and the physics they seek to describe. It begins with an overview of classical Brownian motion and diffusion models, highlighting the central limit theorem, Wiener process, Langevin equation, and fluctuation-dissipation theorem. It then discusses two approaches to generalizing these models: fractional kinetics via continuous time random walks, which modifies diffusion through time subordination; and fractional motions like fractional Brownian motion, which derive from non-Markovian generalizations of the Langevin equation. The document aims to build intuition about these fractional models and their relationships to underlying physical phenomena.
Cyprus 2011 complexity extreme bursts and volatility bunching in solar terres...Nick Watkins
Nick Watkins presented research on complexity and volatility clustering in solar-terrestrial physics. The research began 15 years ago studying multiscale complexity in Earth's magnetosphere. Watkins' focus has been on self-similar and multifractal time series models. He highlighted work on temporal scaling of bursts above thresholds and volatility clustering, a multifractal feature also seen in some financial time series. Watkins advocated using the Kesten stochastic process as a "null" model for framing hypotheses about volatility bunching. The relevance extends beyond solar-terrestrial physics to complex systems modeling.
AGU 2012 Bayesian analysis of non Gaussian LRD processesNick Watkins
Contributed talk at American Geophysical Union Fall Meetinfg, San Francisco, 2012.
Part of work now submitted to Bayesian Analysis, 2014, see eprint: http://arxiv.org/abs/1403.2940
Hyderabad 2010 Distributions of extreme bursts above thresholds in a fraction...Nick Watkins
The document summarizes simulations of burst sizes and durations in fractional Lévy motion processes with varying parameters α and H. The simulations show:
- For fractional Brownian motion (α=2), the predicted scaling relationships for burst length (β=2-H) and size (γ=2/(1+H)) agree reasonably well with simulation results.
- For heavier tailed processes with α=1.6, the predictions also show similar levels of agreement, though not perfect.
- By α=1.2, the very heavy tails cause a clear problem with the predictions not fitting the simulation results well.
The simulations thus provide a test of theoretical scaling relationships for burst statistics in fractional Lé
Venice 2012 Two topics in the history of complexity: Bunched Black Swans and ...Nick Watkins
This document discusses two topics in the history of complexity: "bunched black swans" and the "minds eye". It summarizes the work of Benoit Mandelbrot in developing self-similar models, such as fractional Brownian motion and fractional hyperbolic motion, to model long-range dependence and heavy-tailed distributions seen in natural phenomena like cotton prices and the Nile River. It discusses how Mandelbrot later developed multifractal models to address limitations with purely self-similar models, such as their inability to capture "volatility clustering". The document also discusses cognitive styles and individual differences in visual versus verbal thinking and their relevance to the history of mathematics, science, and future developments in information and communication
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
1. A Random Walk Through Search
Research
Nick Watkins
NickWatkins@mykolab.com
2. Thanks
• Rainer Klages for inviting me to participate in the ASG
• ONR for funding my participation in the ASG
• PKS for my visiting position in 2013-2014, hosted in
Holger Kantz’s group, and visits to this ASG in Dresden
• Ralf Metzler for hosting me at Potsdam during ASG
Discussions with many people including the above, Andy
Edwards, Mervyn Freeman, Sandra Chapman, Yu-Xi Chau,
Eli Barkai, Igor Sokolov, Eugene Murphy, Richard Philips,
Aleksei Chechkin, Gandhi Viswanathan, Gene Stanley,
Marcos Da Luz, and the 2015 ASG team.
3. Overview I
• Brownian paradigm: keeps Central Limit
Theorem, adapts walk models for movement
& search research
• Continuous Time Random Walk & compound
Brownian models as exemplar.
• Non-Brownian paradigms: arise from going to
ECLT and/or modifying time dependence
• Levy Flights/Walks, Fractional Time Process as
resulting exemplars
• Levy Foraging (or Environmental) Hypothesis
as resulting conjectures
4. Overview II
• My current interest: Consequences of
different ways of introducing time
dependence-either Markovian or ergodic
• Disclaimer: First parts strongly influenced by
my own experience in 2005-8 [Edwards,
Philips, Watkins et al, Nature, 2007].
Hopefully, however, its semi-historical nature
sets a stage for those who will go on to bring
you up to date [Zaburdaev, Bartumeus and
others].
5. Movement modelling
• In widespread use, for very diverse reasons …
• Home ranges of foraging animals [e.g. Randon-
Furling et al, PRL, 2009; Claussen et al, 2015]
• Tracking shoppers in malls [e.g. Path Intelligence].
THEORY PRACTICE
7. Why (and which) stochastic model?
• Movement patterns of biological organisms,
including humans, very rich and complex.
• Fortunately, while reasonable to assume that
animal movements deterministic on small
spatiotemporal scales, on larger scales
foraging paths exhibit random patterns so
stochastic approaches to modelling exploited.
• But “randomness” comes in many flavours,
how to choose right one for given case?
9. Random walks & BM
• Pearson quote
The connection of
animal motion and
random walks was
made more than a
century ago by
pioneering
statistician and
biometrician Karl
Pearson.
[Pearson, Biometric
ser., 3, 54 (1906)].
10. Random walks & BM
• Pearson quote
The connection of
animal motion and
random walks was
made more than a
century ago by
pioneering
statistician and
biometrician Karl
Pearson.
[Pearson, Biometric
ser., 3, 54 (1906)].
11. • Pearson also coined the term random
walk when posing it as a problem in a
famous letter to Nature, which was
answered by Lord Rayleigh who
showed the Gaussian nature of the
solution and linked it to a problem
he had solved in physics.
• As the theory of Brownian random
walks and the Wiener process rapidly
developed in statistical physics and
mathematics, this concept came to
dominate the stochastic modeling of
movement in biology.
12. • Pearson also coined the term random
walk when posing it as a problem in a
famous letter to Nature, which was
answered by Lord Rayleigh who
showed the Gaussian nature of the
solution and linked it to a problem
he had solved in physics.
• As the theory of Brownian random
walks and the Wiener process rapidly
developed in statistical physics and
mathematics, this concept came to
dominate the stochastic modeling of
movement in biology.
13. CTRW as archetype
1
( ) i
n
i
X t
1
i
n
n
i
t
/
( )x
Notation as Fulger et al, PRE (2008)
-8 -6 -4 -2 0 2 4 6 8
0
0.5
1
1.5
2
2.5
3
3.5
4
x 10
4
Histogram of jump sizes
0 2 4 6 8 10 12 14
10
0
10
1
10
2
10
3
10
4
10
5
10
6
Semilog histogram of waiting times
( , ) ( ) ( )
14. 2D CTRW
0 1 2 3 4 5 6 7 8 9 10
x 10
5
-1000
-500
0
500
1000
1500
2000
2500
3000
Time
x,ycomponents
Time series
x
y
-1000 -500 0 500 1000 1500
-500
0
500
1000
1500
2000
2500
3000
Spatial pattern
x
y
15. 2D CTRW
0 1 2 3 4 5 6 7 8 9 10
x 10
5
-1000
-500
0
500
1000
1500
2000
2500
3000
Time
x,ycomponents
Time series
x
y
Another choice would
be single random vector
length R with uniform
random angle θ
– which choice is adopted
becomes more important for
non-Brownian cases
-1000 -500 0 500 1000 1500
-500
0
500
1000
1500
2000
2500
3000
Spatial pattern
x
y
16. CTRW = renewal reward process
Here jumps at {J}
become
rewards {W} and
waiting times
become holding
times {S}
Much scope for interplay of maths and physics
17. Compound Brownian ?
• As measurement techniques in experimental biology advanced,
was found that ordinary Brownian motion too simple to generally
represent foraging paths.
• Variations on simple random walk paradigm, notably composite
correlated random walks and complex intermittent search
strategies combining scanning and relocation modes developed and
applied to explain biological movement data with much success [e.g
Benhamou, 2014; Benichou et al, 2011; Campos et al, 2014].
• All generate “normal diffusion” in long time limit, mean squared
displacement of ensemble of foragers grows linearly in time.
19. Symptoms of complex transport: 1
Possibility of very long jumps
(“flights”) compared to the <jump>
20. Anomalous diffusion ?
• However, at least one observed feature of animal foraging (&
human movement) motivates something other than
Brownian, or even compound Brownian, picture.
• Many individuals across a broad range of species observed to
make small local random movements interspersed with rare
long-distance jumps. Particularly true of affluent modern
humans …
• In consequence Brownian theoretical framework for diffusion
in both biology and the physical sciences has been challenged
over the past three decades by a new emerging synthesis.
• This is drawn both from data and from the theory of those
stochastic processes which generate non-Brownian
“anomalous” diffusion, where the mean squared
displacement grows nonlinearly in the long time limit.
21. ECLT
• Brownian motion
paradigm for random
walks was closely linked
to central limit theorem
(CLT), but known for
much of the last century
that relaxing just one of
assumptions-finite
variance-gives a new
class of random walk.
• This class obeys extended
central limit theorem-has
a very different
probability distribution
for the size of a step-
asymptotic power law
tail.
(1 )
( )
0<α< 2
22. Levy flights
• The resulting stochastic movement model is
called a Lévy flight. Intriguingly, like the
biological observations, a “Lévy flyer” has
apparent clusters linked by long jumps.
-0.5 0 0.5 1 1.5 2 2.5
x 10
4
-8000
-6000
-4000
-2000
0
2000
4000
Spatial pattern
x
y
α=1.5,
=1
0 2 4 6 8 10 12
x 10
5
-1
-0.5
0
0.5
1
1.5
2
2.5
x 10
4
Time
x,ycomponents
Time series
x
y
26. Fractional Time Process
• Another type of
anomalous
diffusion-what
you get if you
keep Markovian
structure and
factorising
probability but
allow long tails in
waiting time
between jumps.
Example here is Mittag-Leffler, has advantage that one limit is exponential
27. 0 1 2 3 4 5 6 7 8 9 10
x 10
5
-1000
-500
0
500
1000
1500
2000
2500
3000
Time
x,ycomponents
Time series
x
y
FTP Time series
0 0.5 1 1.5 2 2.5 3 3.5 4
x 10
6
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
Time
x,ycomponents
Time series
x
y
α=2, β= 0.9
Brownian example for
comparison
28. Can Combine LF & FTP
0 0.5 1 1.5 2 2.5
x 10
8
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
x 10
4
Time
x,ycomponents
Time series
x
y
α=1.5, β=0.7
-14000 -12000 -10000 -8000 -6000 -4000 -2000 0 2000 4000
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
x 10
4
Spatial pattern
x
y
time series
space
Called “Fully Fractional CTRW”
29. Dollar bills [Brockmann, 2006]
Data fitted to an FFCTRW with α, β both about 0.6
See also Bartumeus, Giuggioli et al’s work on Shearwaters, 2010
30. 08/09/2015
From supp. Info. of [Brockmann et al, 2006] comes very useful schematic-
NB they defined (,) opposite way to Fulger and others.
Actually not fBm,
but rather in fact the
fractional time
process (FTP).
Don’t believe
everything you
read in Nature ;-)
Can Combine LF & FTP
31. Another way: couple space to time
Gives a finite velocity by introducing a jump duration τ’ & coupling
the jump size to it – idea known as Lévy walk
[Shlesinger & Klafter, PRL (1985)].
( , ') ( '| ) ( )
(| | ') ( )
Lévy walk
( , ) ( ) ( ) Uncoupled CTRW
In above τ’ means flight duration in Levy walk, and
τ waiting time in CTRW.
32. Viswanathan et al
1996 [V96]
“In the days of sail the bird often
accompanied ships for days, not merely
following it, but wheeling in wide circles
around it without ever being observed to
land on the water.“ - Wikipedia
33. Time series data is number of consecutive hours that
bird is not wet.
13:00 14:00 15:00 16:00 17:00
Dry for full hour
Wet at least once Wet at least once
Data:
36. Lévy Foraging Hypothesis I
Schlesinger & Klafter ended their comparison of Lévy
walks & Lévy flights in a landmark 1985 NATO ASI
volume with this comment: “ It has been suggested
[B. Ninham, priv. comm.] that certain animals such as
ants perform Levy walks when searching for food in a
new area. The above analysis may imply that starving
Levy walk ants possess a slight evolutionary
advantage over ants performing other walks, such as
even the [self avoiding walk]. Flying ants can be
considered by the reader.” – in “On Growth & Form”,
Stanley & Ostrowsky (eds. ) Editions Nijhoff,
1986.
37. Lévy Foraging Hypothesis I
Schlesinger & Klafter ended their comparison of Lévy
walks & Lévy flights in a landmark 1985 NATO ASI
volume with this comment: “ It has been suggested
[B. Ninham, priv. comm.] that certain animals such as
ants perform Levy walks when searching for food in a
new area. The above analysis may imply that starving
Levy walk ants posess a slight evolutionary
advantage over ants performing other walks, such as
even the [self avoiding walk]. Flying ants can be
considered by the reader.” – in “On Growth & Form”,
Stanley & Ostrowsky (eds. ) Editions Nijhoff,
1986.
42. Edwards et al, op cit.
• Waiting times
after correction:
Short-tailed, unlike a Lévy walk ...but like the “ studies
[which] found [birds spent]... as long as 18 hours a
day in flight”: Poncet, Nat. Geographic, March 1989.
43. Re-examination of LW/LFH …
• Travis, 2007; Buchanan, 2008; Barabasi,
2010;Viswanathan et al 2012. ...
44. … only increased activity in the field
Pyke, 2014
Two particular legacies of time:
Renewed attention to statistical
inference and other issues around
measurement
Consideration of a wider range
of models and paradigms
45. How would cleverest random
walker play battleships
How does even young child play
battleships ?
Gedanken experiment
48. Choices for time dependence
• CTRW is Markovian in structure- “memory” is
modelled by using heavy tailed times between
jumps. [Mandelbrot, 65-67] knew that FTP-
like process was non-ergodic because its
periodogram grows with observation time !
• Alternative is an ergodic, non-Markovian
process where memory is embodied in the
kernel [Mandelbrot and co-authors, 65-68]
51. The conditional spectrum:
Magnetosphere
Mandelbrot 1967 reviewed in N2, Selecta, 1999
• “Numerical … 1/f … spectrum … need not … estimate …
Wiener-Khinchine spectrum”. Instead “depends on
conditioning length T”. Unlike stationary LRD model,
singularity is an artefact.
52. Ionosphere
Magnetosphere
1 1
2 2
, 22fBm: ( ) ( ) ( )~ ( )
H
H R
H
X t t s s dL s
Infinite range
memory kernel
Gaussian
fBm
53. Ionosphere
Magnetosphere
[…], if infinite dependence is necessary it does not mean
that IBM's details of ten years ago influence IBM today,
because there's no mechanism within IBM for this
dependence. However, IBM is not alone. The River Nile is
[not] alone. They're just one-dimensional corners of
immensely big systems. The behaviour of IBM stock ten
years ago does not influence its stock today through IBM, but
IBM the enormous corporation has changed the environment
very strongly. The way its price varied, went up or went up
and fluctuated, had discontinuities, had effects upon all kinds
of other quantities, and they in turn affect us. –
Mandelbrot, interviewed in 1998 by B. Sapoval for Web of
Stories
What does fBm mean ?
54. Ionosphere
Magnetosphere
[…], if infinite dependence is necessary it does not mean
that IBM's details of ten years ago influence IBM today,
because there's no mechanism within IBM for this
dependence. However, IBM is not alone. The River Nile is
[not] alone. They're just one-dimensional corners of
immensely big systems. The behaviour of IBM stock ten
years ago does not influence its stock today through IBM, but
IBM the enormous corporation has changed the environment
very strongly. The way its price varied, went up or went up
and fluctuated, had discontinuities, had effects upon all kinds
of other quantities, and they in turn affect us. –
Mandelbrot, interviewed in 1998 by B. Sapoval for Web of
Stories
What does fBm mean ?
• Resolution of apparent paradox is that world as a whole is
Markovian, the memory is a consequence of looking at a
piece of it. Generalises the Mori-Zwanzig idea.
55. Conclusions
• Random walks and biology co-evolved from
earliest days
• Still a productive dialogue to which ASG will
contribute
• Also links to deep and current issues in
fundamental statistical mechanics such as
weak ergodicity breaking
59. Theme
(S)LRD
1/f
Hurst
effect
Will today distinguish three
things often taken as same
• Observed growth of range
in time series: “Hurst
effect”
• Observation of a singularity
at zero in Fourier spectra:
“1/f”
• The long range dependence
seen in stationary 1/f case:
(S)LRD.
• Using 1/f as a diagnostic of
LRD assumes stationarity
60. Fact: Anomalous growth of range
Hurst
Effect
Hurst, Nature, 1957
“I heard about the … Nile … in '64, ... the variance doesn't draw l
time span as you take bigger and bigger integration intervals;
it goes like time to a certain power different from one. … Hurst …
was getting results that were incomprehensible”. – Mandelbrot, 1
61. Formula: Long Range Dependence
(S)LRD
Hurst
Effect
• Mandelbrot, van Ness, and
Wallis, 1965-69
• First [history in Graves et al,
arXiv, 2014a] demonstration
that Hurst effect could be
explained by stationary long
range dependent process
• Model, fractional Gaussian
noise [see also Kolmogorov’s
“Wiener Spiral”], had singular
spectral density at lowest
frequencies.
'( ) ~
S f f
62. The 1/f “paradox”
If spectral density '( )
then i) it is singular as
and ii) if we define an autocorrelation
function via ( ) ( ) ( )
and use Wiener-Khinchine theorem to
get from Fourier transform of
~
0
S f f
f
x t x t
S
falls off as power law, and
'( )
then
summed lags "blow up"
its
( )
f
63. Fractional motions and noises
0 100 200 300 400 500 600 700 800 900 1000
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
Fractional Brownian motion, H=0.7
1 1
2 2
, 22fBm: ( ) ( ) ( )~ ( )
H
H R
H
X t t s s dL s
Build a nonstationary, self
similar walk … (used wfbm in
Matlab)
fractional motion
2 1 H
64. Fractional motions and noises
0 100 200 300 400 500 600 700 800 900 1000
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
Fractional Brownian motion, H=0.7
1 1
2 2
, 22fBm: ( ) ( ) ( )~ ( )
H
H R
H
X t t s s dL s
Build a nonstationary, self
similar walk … (used wfbm in
Matlab)
0 100 200 300 400 500 600 700 800 900 1000
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Fractional Gaussian noise
fractional motion
Then differentiate to give a
stationary LRD noise
fractional noise
2 1 H 2 1 H
65. 1/f without (S)LRD
(S)LRD
1/f
Hurst
effect
• Before (S)LRD models,
Mandelbrot [1963-67]
had proposed other 1/f
models which were not
stationary LRD in same
sense as fGn.
• Solved 1/f paradox by a
different route. Still
little known in the
geosciences [but see
Klemes, WRR, 1974].
66. Formula versus fact
“Like the ear, the eye is very
sensitive to features that the
spectrum does not reflect. Seen
side by side, different 1/f noises,
Gaussian [i.e. fGn], dustborne [i.e.
fractional renewal] and multifractal,
obviously differ from one another”-
Mandelbrot, Selecta N, 1999.
“Nothing can be more fatal to
progress than a too confident
reliance on mathematical symbols;
for the student is only too apt to …
consider the formula and not the
fact as the physical reality”.
Thomson (Kelvin) & Tait, 1890
edition.
70. Boyer et al (2008)
• Boyer et al, arXiv, 2008 pointed out that jump
sizes of foraging model in Viswanathan et al,
1999 not same as those of simple Levy walk
used in Viswanathan et al, 1996. Worked out
distribution explicitly: