Gait abnormalities ... of how a person walks is called the gait. Different types of walking problems occur without a ... Some walking abnormalities have been given names: Propulsive gait -- a stooped, stiff posture with the head and ...
... get around, and exercise. Having a problem with walking can make daily life more difficult. The pattern ... an abnormal gait and lead to problems with walking. These include: Injuries, diseases, or abnormal development of ...
... daily activities, get around, and exercise. Having a problem with walking can make daily life more difficult. ... walk is called your gait. A variety of problems can cause an abnormal gait and lead to ...
Symes, Mark D
2009-01-01
Inspired by the motor protein kinesin, an ambitious and unprecedented mimic is proposed – a synthetic molecular motor that can walk. This thesis aims to explain the basic principles which define such walking molecules, ...
Brown, Scott C.; Pantin, Hilda; Lombard, Joanna; Toro, Matthew; Huang, Shi; Plater-Zyberk, Elizabeth; Perrino, Tatiana; Perez-Gomez, Gianna; Barrera-Allen, Lloyd; Szapocznik, José
2013-01-01
Background Walk Score® is a nationally and publicly available metric of neighborhood walkability based on proximity to amenities (e.g., retail, food, schools). However, few studies have examined the relationship of Walk Score to walking behavior. Purpose To examine the relationship of Walk Score to walking behavior in a sample of recent Cuban immigrants, who overwhelmingly report little choice in their selection of neighborhood built environments when they arrive in the U.S. Methods Participants were 391 recent healthy Cuban immigrants (M age=37.1 years) recruited within 90 days of arrival in the U.S., and assessed within 4 months of arrival (M=41.0 days in the U.S.), who resided throughout Miami-Dade County FL. Data on participants’ addresses, walking and sociodemographics were collected prospectively from 2008 to 2010. Analyses conducted in 2011 examined the relationship of Walk Score for each participant’s residential address in the U.S. to purposive walking, controlling for age, gender, education, BMI, days in the U.S., and habitual physical activity level in Cuba. Results For each 10-point increase in Walk Score, adjusting for covariates, there was a significant 19% increase in the likelihood of purposive walking, a 26% increase in the likelihood of meeting physical activity recommendations by walking, and 27% more minutes walked in the previous week. Conclusions Results suggest that Walk Score is associated with walking in a sample of recent immigrants who initially had little choice in where they lived in the U.S. These results support existing guidelines indicating that mixed land use (such as parks and restaurants near homes) should be included when designing walkable communities. PMID:23867028
Butler, B.
1994-12-31
Earth Day, celebrated this April, brought out a spate of press conferences, fairs and media spots. The White House announced its plans to green itself by incorporating energy efficiency and recycling, and Vice President Gore and Energy Secretary O`Leary announced the President`s Executive Order, which mandates the use of energy efficiency in federal facilities with solar as a high-profile option. At the White House itself, however, no solar application has yet been selected for installation. Another Earth Day media spot showed how the nation`s utility companies have joined Secretary O`Leary`s Climate Challenge, an ambitious voluntary program to cut greenhouse-gas emissions. During Earth Day 1994, it became clear how many houses use solar water heating and how often photovoltaics is used to power road signs and sign boards, telephones and repeaters, and for cathodic protection and security lighting. Solar energy is expanding. But if it is to become a truly everyday technology, more institution, governments, businesses and individual consumers are going to have to walk the walk. This means that Earth Day will have to last longer, environmental concerns must become more genuine, and the focus of government and business decisions must be more long-term.
Walking Perception by Walking Observers
ERIC Educational Resources Information Center
Jacobs, Alissa; Shiffrar, Maggie
2005-01-01
People frequently analyze the actions of other people for the purpose of action coordination. To understand whether such self-relative action perception differs from other-relative action perception, the authors had observers either compare their own walking speed with that of a point-light walker or compare the walking speeds of 2 point-light…
NSDL National Science Digital Library
Clinton Robertson (None; )
2006-09-23
Some animals can camouflage themselves in the way that they appear to be an actual element of their environments. The walking stick bug blends into its surroundings because predators probably mistake them for ordinary tree twigs.
NSDL National Science Digital Library
2012-08-23
In this activity, learners walk the sides and interior angles of various polygons drawn on the playground. As they do so, learners practice rotating clockwise 180° and 360°. Learners discover there is a pattern to the sum of the interior angles of any polygon.
Quantum random walks without walking
Manouchehri, K.; Wang, J. B. [School of Physics, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia)
2009-12-15
Quantum random walks have received much interest due to their nonintuitive dynamics, which may hold the key to a new generation of quantum algorithms. What remains a major challenge is a physical realization that is experimentally viable and not limited to special connectivity criteria. We present a scheme for walking on arbitrarily complex graphs, which can be realized using a variety of quantum systems such as a Bose-Einstein condensate trapped inside an optical lattice. This scheme is particularly elegant since the walker is not required to physically step between the nodes; only flipping coins is sufficient.
NSDL National Science Digital Library
National 4-H Council
2009-01-01
In this activity, learners take an indoor nature walk and discover various objects that have been brought in from the outdoor environment. In preparation for the activity, an educator places natural and man-made items around a room for learners to discover. Learners examine what they find and make notes about what they see and smell, how they (the learners) feel, and what each item looks like (including sketches). Then the group addresses the topic of "Leave No Trace" as it applies to a real nature walk. This would be a great activity before a field trip to a park, arboretum, or other outdoor environment, and can be done with one learner, a class, or even a large group at a family science event.
Non-classical Random Walks Non-classical Random Walks
Peterson, Jonathon
Non-classical Random Walks Non-classical Random Walks Simple models, surprising results Jonathon Peterson 4/25/2009 1 / 25 #12;Non-classical Random Walks Outline 1 Classical Random Walks Jonathon Peterson 4/25/2009 2 / 25 #12;Non-classical Random Walks Outline 1 Classical Random Walks 2 Random Walks
Complementarity and quantum walks
Kendon, Viv [QOLS, Optics Section, Blackett Laboratory, Imperial College, London, SW7 2BW (United Kingdom); School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom); Sanders, Barry C. [Institute for Quantum Information Science, University of Calgary, Alberta T2N 1N4 (Canada); Centre for Quantum Computer Technology, Macquarie University, Sydney, New South Wales 2109 (Australia)
2005-02-01
We show that quantum walks interpolate between a coherent 'wave walk' and a random walk depending on how strongly the walker's coin state is measured; i.e., the quantum walk exhibits the quintessentially quantum property of complementarity, which is manifested as a tradeoff between knowledge of which path the walker takes vs the sharpness of the interference pattern. A physical implementation of a quantum walk (the quantum quincunx) should thus have an identifiable walker and the capacity to demonstrate the interpolation between wave walk and random walk depending on the strength of measurement.
Relation between random walks and quantum walks
NASA Astrophysics Data System (ADS)
Boettcher, Stefan; Falkner, Stefan; Portugal, Renato
2015-05-01
Based on studies of four specific networks, we conjecture a general relation between the walk dimensions dw of discrete-time random walks and quantum walks with the (self-inverse) Grover coin. In each case, we find that dw of the quantum walk takes on exactly half the value found for the classical random walk on the same geometry. Since walks on homogeneous lattices satisfy this relation trivially, our results for heterogeneous networks suggest that such a relation holds irrespective of whether translational invariance is maintained or not. To develop our results, we extend the renormalization-group analysis (RG) of the stochastic master equation to one with a unitary propagator. As in the classical case, the solution ? (x ,t ) in space and time of this quantum-walk equation exhibits a scaling collapse for a variable xdw/t in the weak limit, which defines dw and illuminates fundamental aspects of the walk dynamics, e.g., its mean-square displacement. We confirm the collapse for ? (x ,t ) in each case with extensive numerical simulation. The exact values for dw themselves demonstrate that RG is a powerful complementary approach to study the asymptotics of quantum walks that weak-limit theorems have not been able to access, such as for systems lacking translational symmetries beyond simple trees.
ERIC Educational Resources Information Center
Mason, Nick
2007-01-01
A generation ago, it was part of growing up for all kids when they biked or walked to school. But in the last 30 years, heavier traffic, wider roads and more dangerous intersections have made it riskier for students walking or pedaling. Today, fewer than 15 percent of kids bike or walk to school compared with more than 50 percent in 1969. In the…
Tad Mcgeer
1990-01-01
There exists a class of two-legged machines for which walking is a natural dynamic mode. Once started on a shallow slope, a machine of this class will settle into a steady gait quite comparable to human walking, without active control or en ergy input. Interpretation and analysis of the physics are straightforward; the walking cycle, its stability, and its sensi
Walking Wellness. Student Workbook.
ERIC Educational Resources Information Center
Sweetgall, Robert; Neeves, Robert
This comprehensive student text and workbook, for grades four through eight, contains 16 workshop units focusing on walking field trips, aerobic pacing concepts, walking techniques, nutrition, weight control and healthy life-style planning. Co-ordinated homework assignments are included. The appendixes include 10 tips for walking, a calorie chart,…
Hamilton, Craig S; Kruse, Regina; Sansoni, Linda; Silberhorn, Christine; Jex, Igor
2014-08-22
We introduce the concept of a driven quantum walk. This work is motivated by recent theoretical and experimental progress that combines quantum walks and parametric down-conversion, leading to fundamentally different phenomena. We compare these striking differences by relating the driven quantum walks to the original quantum walk. Next, we illustrate typical dynamics of such systems and show that these walks can be controlled by various pump configurations and phase matchings. Finally, we end by proposing an application of this process based on a quantum search algorithm that performs faster than a classical search. PMID:25192097
Walking Out and On ARE YOU A WALK OUT?
Sheridan, Jennifer
Walking Out and On EXCERPT ARE YOU A WALK OUT? All systems go through lifecycles. There's progress can be created either inside or outside the failing system. But if we choose to walk out and walk on that the distractions are gone. Walk Outs need to do this kind of hospice work on ourselves. Even as we stop struggling
Tyler Helmuth
2014-10-12
Loop-weighted walk with parameter $\\lambda\\geq 0$ is a non-Markovian model of random walks that is related to the loop $O(N)$ model of statistical mechanics. A walk receives weight $\\lambda^{k}$ if it contains $k$ loops; whether this is a reward or punishment for containing loops depends on the value of $\\lambda$. A challenging feature of loop-weighted walk is that it is not purely repulsive, meaning the weight of the future of a walk may either increase or decrease if the past is forgotten. Repulsion is typically an essential property for lace expansion arguments. This article circumvents the lack of repulsion and proves, via the lace expansion, that for any $\\lambda\\geq 0$ loop-weighted walk is diffusive in high dimensions.
Hari Krovi
2007-11-12
A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. Hitting times for discrete quantum walks on graphs give an average time before the walk reaches an ending condition. We derive an expression for hitting time using superoperators, and numerically evaluate it for the walk on the hypercube for various coins and decoherence models. We show that, by contrast to classical walks, quantum walks can have infinite hitting times for some initial states. We seek criteria to determine if a given walk on a graph will have infinite hitting times, and find a sufficient condition for their existence. The phenomenon of infinite hitting times is in general a consequence of the symmetry of the graph and its automorphism group. Symmetries of a graph, given by its automorphism group, can be inherited by the evolution operator. Using the irreducible representations of the automorphism group, we derive conditions such that quantum walks defined on this graph must have infinite hitting times for some initial states. Symmetry can also cause the walk to be confined to a subspace of the original Hilbert space for certain initial states. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph and we give an explicit construction of the quotient graph. We conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speed-up. Finally, we use symmetry and the theory of decoherence-free subspaces to determine when the subspace of the quotient graph is a decoherence-free subspace of the dynamics.
Norio Konno
2015-02-11
The discrete-time quantum walk (QW) has been extensively and intensively investigated for the last decade, whose coin operator is defined by a unitary matrix. We extend the QW to a walk determined by a unitary matrix whose component is quaternion. We call this model quaternionic quantum walk (QQW) and present some properties. This paper is the first step for the study on QQWs.
NSDL National Science Digital Library
2012-12-13
In this fun group activity involving music and movement, learners are introduced to the idea that many insects walk by using their legs to create "alternating triangles." Learners sing the "Ants Go Marching" song and then study insect specimens. They make models of insects with six legs using Styrofoam and dowels or pencils and brainstorm ideas about how insects walk with all those legs. The most active part of The Bug Walk is when learners, in groups of five, pretend they are an insect's body and simulate an insect's movement. At the end, they discuss what it was like, what problems they had, and ideas for how their walk could have been easier.
NSDL National Science Digital Library
R. McNeill Alexander (University of Leeds; School of Biology)
2005-04-01
Access to the article is free, however registration and sign-in are required: It is possible to design robots that walk in a humanlike manner by providing them with motors to drive every joint and a computer that tells every joint what its angle should be. There are many successful robots of this ilk, but they are very complex and use far more energy than would a walking human. In his Perspective, Alexander discusses a different type of robot inspired by toys that walk passively downhill. These robots have much simpler control systems and use much less energy than conventional walking robots.
10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.
Code of Federal Regulations, 2011 CFR
2011-01-01
... Definitions concerning walk-in coolers and walk-in freezers. 431.302...AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers § 431.302 Definitions concerning walk-in coolers and walk-in freezers....
Preferred walking route (off campus)
Balasuriya, Sanjeeva
Motorcycle Emergency telephone ATM LEGEND Preferred walking route (off campus) Preferred walking route assistance phone the Visitors Information Centre on 9351 3100 LEGEND Medical centre Motorcycle parking
Skryabin, Dmitry V.; Champneys, Alan R.
2001-06-01
A family of walking solitons is obtained for the degenerate optical parametric oscillator below threshold. The loss-driven mechanism of velocity selection for these structures is described analytically and numerically. Our approach is based on understanding the role played by the field momentum and generic symmetry properties and, therefore, it can be easily generalized to other dissipative multicomponent models with walk off.
NASA Technical Reports Server (NTRS)
Vykukal, H. C.; Chambers, A. B.; Stjohn, R. H. (inventors)
1977-01-01
A walking boot assembly particularly suited for use with a positively pressurized spacesuit is presented. A bootie adapted to be secured to the foot of a wearer, an hermetically sealed boot for receiving the bootie having a walking sole, an inner sole, and an upper portion adapted to be attached to an ankle joint of a spacesuit, are also described.
Brennen, Gavin K.; Ellinas, Demosthenes; Kendon, Viv; Pachos, Jiannis K. Tsohantjis, Ioannis; Wang Zhenghan
2010-03-15
The one dimensional quantum walk of anyonic systems is presented. The anyonic walker performs braiding operations with stationary anyons of the same type ordered canonically on the line of the walk. Abelian as well as non-Abelian anyons are studied and it is shown that they have very different properties. Abelian anyonic walks demonstrate the expected quadratic quantum speedup. Non-Abelian anyonic walks are much more subtle. The exponential increase of the system's Hilbert space and the particular statistical evolution of non-Abelian anyons give a variety of new behaviors. The position distribution of the walker is related to Jones polynomials, topological invariants of the links created by the anyonic world-lines during the walk. Several examples such as the SU(2){sub k} and the quantum double models are considered that provide insight to the rich diffusion properties of anyons.
Short Hyperuniform Random Walks
NASA Astrophysics Data System (ADS)
Casini, Emanuele; Le Caër, Gérard; Martinelli, Andrea
2015-07-01
Random walks of two steps, with fixed sums of lengths of , taken into uniformly random directions in d-dimensional Euclidean spaces () are investigated to construct continuous step-length distributions which make them hyperuniform. The endpoint positions of hyperuniform walks are spread out in the unit ball as the projections in the walk space of points uniformly distributed on the surface of the unit hypersphere of some k-dimensional Euclidean space (). Unique symmetric continuous step-length distributions exist for given d and k, provided that . The walk becomes uniform on the unit ball when . The symmetric densities reduce to simple polynomials for uniform random walks and are mixtures of two pairs of asymmetric beta distributions.
From open quantum walks to unitary quantum walks
Chaobin Liu
2015-02-05
We present an idea to convert to a unitary quantum walk any open quantum walk which is defined on lattices as well as on finite graphs. This approach generalizes to the domain of open quantum walks (or quantum Markov chains) the framework introduced by Szegedy for quantizing Markov chains. For the unitary quantum walks formulated in this article, we define the probability and the mean probability of finding the walk at a node, then derive the asymptotic mean probability.
Gordon Slade
Simple random walk is well understood. However, if we condition a random walk not to intersect itself, so that it is a self-avoiding walk, then it is much more di-- cult to analyse and many of the important mathematical problems remain unsolved. This paper provides an overview of some of what is known about the self-avoiding walk, includ- ing some
Quantum walks with history dependence
A P Flitney; D Abbott; N F Johnson
2004-01-01
We introduce a multi-coin discrete quantum walk where the amplitude for a coin flip depends upon previous tosses. Although the corresponding classical random walk is unbiased, a bias can be introduced into the quantum walk by varying the history dependence. By mixing the biased walk with an unbiased one, the direction of the bias can be reversed leading to a
Walk Across Texas! Recruitment Brochure
Walk Across Texas! Recruitment Brochure See next page for ordering instructions #12;How to Order where you can order the Walk Across Texas! brochures, bookmark or mini poster FREE. 4. Then, search MKT-3131K Walk Across Texas! Miniposter MKT-3131 Walk Across Texas! recruitment brochure Place your
NASA Astrophysics Data System (ADS)
Schwienbacher, Markus; Favot, Valerio; Buschmann, Thomas; Lohmeier, Sebastian; Ulbrich, Heinz
Based on the experience gathered from the walking robot Johnnie the new performance enhanced 25-DoF humanoid robot Lola was built. The goal of this project is to realize a fast, human-like walking. This paper presents different aspects of this complex mechatronic system. Besides the overall lightweight construction, custom build multi-sensory joint drives with high torque brush-less motors were crucial for reaching the performance goal. A decentralized electronics architecture is used for joint control and sensor data processing. A simulation environment serves as a testbed for the walking control, to minimize the risk of damaging the robot hardware during real world experiments.
NSDL National Science Digital Library
2012-08-27
This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Sierra walks her dog Pepper twice a day. Her evening walk is two and a half times as far as her morning walk. At the end of the week she tells her mom,...
When Human Walking is a Random Walk
NASA Astrophysics Data System (ADS)
Hausdorff, J. M.
1998-03-01
The complex, hierarchical locomotor system normally does a remarkable job of controlling an inherently unstable, multi-joint system. Nevertheless, the stride interval --- the duration of a gait cycle --- fluctuates from one stride to the next, even under stationary conditions. We used random walk analysis to study the dynamical properties of these fluctuations under normal conditions and how they change with disease and aging. Random walk analysis of the stride-to-stride fluctuations of healthy, young adult men surprisingly reveals a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales (Hausdorff et al, J Appl Phsyiol, 1995). To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 hour at their usual pace, as well as at slower and faster speeds. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to a thousand strides at all three walking rates. In contrast, during metronomically-paced walking, these long-range correlations disappeared; variations in the stride interval were uncorrelated and non-fractal (Hausdorff et al, J Appl Phsyiol, 1996). To gain insight into the mechanism(s) responsible for this fractal property, we examined the effects of aging and neurological impairment. Using detrended fluctuation analysis (DFA), we computed ?, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. ? was significantly lower in healthy elderly subjects compared to young adults (p < .003) and in subjects with Huntington's disease, a neuro-degenerative disorder of the central nervous system, compared to disease-free controls (p < 0.005) (Hausdorff et al, J Appl Phsyiol, 1997). ? was also significantly related to degree of functional impairment in subjects with Huntington's disease (r=0.78). Recently, we have observed that just as there are changes with ? during aging, there also changes with development. Apparently, the fractal scaling of walking does not become mature until children are eleven years old. Conclusions: The fractal dynamics of spontaneous stride interval fluctuations are normally quite robust and are apparently intrinsic to the healthy adult locomotor system. However, alterations in this fractal scaling property are associated with impairment in central nervous system control, aging and neural development.
Sable, C.
1987-06-09
This patent describes a pumping unit for reciprocating rod-operated well pumps comprising a motor, a crankshaft driven by the motor, a crank having an end driven from the crankshaft, a samson post having a top, a fixed position horizontal shaft at the top of the samson post, a walking beam having a first end and a second end rockable about a horizontal axis, a first shaft at the first end of the walking beam. It is pivotally coupled to the end of the crank. An operating rod is pivotally coupled to the second end of the walking beam. A hangar arm of predetermined length is suspended from the fixed position horizontal shaft for pivotal movement thereabout. A further horizontal shaft is movable through a circular arc by which the hanger arm is pivotally coupled to the walking beam at a point intermediate its ends.
Everyday Fitness Ideas from the National Institute on Aging at NIH www.nia.nih.gov/Go4Life Walking for Your ... breathing. Endurance exercises keep you healthy, improve your fitness, and help you do the tasks you need ...
Generic Quantum Walks with Memory
Dan Li; Michael Mc Gettrick; Fei Gao; Jie Xu; Qiao-Yan Wen
2015-08-31
Quantum walks with memory are a type of modified quantum walk that records the walker's latest path. In this work, we show that a quantum walk with memory on a digraph can be transformed as a quantum walk without memory on the line digraph of the original one. With this correspondence, we construct a model which includes all possible standard quantum walks with memory on regular graphs. This construction would help us to study quantum walks with memory and also help in corresponding experiments. Based on this model, by taking the straight line as example, we study the general properties of quantum walks with memory, such as variance, occupancy rate and localization. Interestingly, we find that a quantum walk with memory can produce the same probability distribution as that of a standard quantum walk whose initial spin state is $\\sqrt{\\frac{1}{2}}|0\\rangle_p(|1\\rangle_c+i|-1\\rangle_c)$.
Locomotion: Why We Walk the Way We Walk.
Bertram, John E A
2015-09-21
The way we walk determines the energetic investment needed. Humans spontaneously alter their walking style to exploit energetic opportunities. New research demonstrates the sensitivity and timing of this optimization and opens the door to discovering the underlying mechanisms. PMID:26394100
CyberWalk: Enabling Unconstrained Omnidirectional Walking through Virtual Environments
De Luca, Alessandro
: Virtual reality, locomotion, treadmill, spatial navigation, control system ACM Reference Format: Souman, J for Biological Cybernetics Despite many recent developments in virtual reality, an effective locomotion interface25 CyberWalk: Enabling Unconstrained Omnidirectional Walking through Virtual Environments J. L
Mechanics of competition walking.
Cavagna, G A; Franzetti, P
1981-01-01
1. The work done at each step to lift and accelerate the centre of mass of the body has been measured in competition walkers during locomotion from 2 to 20 km/hr. 2. Three distinct phases characterize the mechanics of walking. From 2 to 6 km/hr the vertical displacement during each step, Sv, increases to a maximum (3.5 vs. 6 cm in normal walking) due to an increase in the amplitude of the rotation over the supporting leg. 3. The transfer, R, between potential energy of vertical displacement and kinetic energy of forward motion during this rotation, reaches a maximum at 4-5 km/hr (R = 65%). From 6 to 10 km/hr R decreases more steeply than in normal walking, indicating a smaller utilization of the pendulum-like mechanism characteristic of walking. 4. Above 10 km/hr potential and kinetic energies vary during each step because both are simultaneously taken up and released by the muscles with almost no transfer between them (R = 2-10%). Above 13-14 km/hr an aerial phase (25-60 msec) takes place during the step. 5. Speeds considerably greater than in normal walking are attained thanks to a greater efficiency of doing positive work. This is made possible by a mechanism of locomotion allowing an important storage and recovery of mechanical energy by the muscles. PMID:7310710
Labyrinth walking in corrections.
Zucker, Donna M; Sharma, Amy
2012-02-01
A 6 week labyrinth walking program was pilot tested in a correctional setting and goals were to: 1) determine the feasibility of a labyrinth walking curriculum; 2) pilot test measures of health related quality of life (QOL) (pre and post-surveys) and blood pressure; and 3) examine the influence of relationship-centered teaching on subject satisfaction. Relational communication was used as a framework for this study, emphasizing concepts of trust, competency and similarly in the teacher. A pretest/posttest descriptive design was used. The sample was 14 offenders at a Massachusetts county jail. The intervention included six 90 minute sessions, composed of a lecture, a labyrinth walk, and journal writing. Measures included a demographic survey; pre and post session walk blood pressures; pre and post program QOL measures; and a post program measure of satisfaction. The sample was 57% Caucasian, 36% Hispanic, and 7% African American, with an average age of 34, mostly high school educated and single. Drug of choice was alcohol with age of use at 12 and 1/2 years. Seventy-nine percent were previously incarcerated more than twice. QOL data were not changed pre to post. BP data trended in a healthy direction from weeks 1 to 6. Satisfaction with the teacher and the program was high. The labyrinth walking pilot program was proven feasible, low cost and satisfying for the participants. Recommendations for future studies are discussed. PMID:22468660
Quantum Random Walk via Classical Random Walk With Internal States
Kovchegov, Yevgeniy
Quantum Random Walk via Classical Random Walk With Internal States Robert M. Burton1, Yevgeniy, OR 97331-4605, USA Abstract. In recent years quantum random walks have garnered much inter- est among quantum information researchers. Part of the reason is the prospect that many hard problems can be solved
a walking tour of ALONG THE OLIVE WALK
Stoltz, Brian M.
a walking tour of Caltech ALONG THE OLIVE WALK #12;2 The California Institute of Technology. On pages 14 and 15, you will find a campus map with a key for this walking tour. Our first stop is down traditionally begins the year here, with a backyard picnic the evening before the students leave for a three
BIOPHYSICS: Myosin Motors Walk the Walk
NSDL National Science Digital Library
Justin E. Molloy (National Institute for Medical Research; Division of Physical Biochemistry)
2003-06-27
Access to the article is free, however registration and sign-in are required. Myosin molecular motors move along actin filaments to drive, for example, muscle contraction or the intracellular trafficking of vesicles. However, it has not been clear whether myosin V moves along actin filaments in a hand-over-hand or inchworm fashion. In their Perspective, Molloy and Veigel explain new work (Yildiz et al.) that provides evidence in support of the hand-over-hand model for how myosin V walks along actin.
Biomechanical conditions of walking
Fan, Y F; Luo, L P; Li, Z Y; Han, S Y; Lv, C S; Zhang, B
2015-01-01
The development of rehabilitation training program for lower limb injury does not usually include gait pattern design. This paper introduced a gait pattern design by using equations (conditions of walking). Following the requirements of reducing force to the injured side to avoid further injury, we developed a lower limb gait pattern to shorten the stride length so as to reduce walking speed, to delay the stance phase of the uninjured side and to reduce step length of the uninjured side. This gait pattern was then verified by the practice of a rehabilitation training of an Achilles tendon rupture patient, whose two-year rehabilitation training (with 24 tests) has proven that this pattern worked as intended. This indicates that rehabilitation training program for lower limb injury can rest on biomechanical conditions of walking based on experimental evidence.
Caceres, Alan Joseph J; Castillo, Juan; Lee, Jinnie; St John, Katherine
2013-01-01
A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, T1, T2, . . . , T(k) where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNI-walks that visit all trees in a subtree-prune-and-regraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, T, on n leaves, the shortest walk takes ?(n²) additional steps more than the number of trees in the SPR neighborhood. This answers Bryant’s Second Combinatorial Challenge from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and the Penny Ante Problem List, 2009. PMID:23702562
Reduced Gravity Walking Simulator
NASA Technical Reports Server (NTRS)
1963-01-01
A test subject being suited up for studies on the Reduced Gravity Walking Simulator located in the hangar at Langley Research Center. The initial version of this simulator was located inside the hangar. Later a larger version would be located at the Lunar Landing Facility. This position meant that a person's legs experienced only one sixth of their weight, which was the equivalent of being on the lunar surface. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion.
Unknown
2007-10-08
, exercising just bef.ore bedtime may make it difficult to relax enough for easy sleep. 5. Find ample space with non-slip padding. About a 6-foot square is needed. 3 6. Perform exercises slowly without quick, jerky movements. This helps prevent.... This is highly im- probable. 13. Avoid measuring im- mediately after exercis- Walk. Of course, not all per sons are able to start hard physical exercise, but they still need some kind of physi cal activity. Walking is one of the best ways to start a physi...
ERIC Educational Resources Information Center
Bailey, Herb; Kalman, Dan
2011-01-01
Fay and Sam go for a walk. Sam walks along the left side of the street while Fay, who walks faster, starts with Sam but walks to a point on the right side of the street and then returns to meet Sam to complete one segment of their journey. We determine Fay's optimal path minimizing segment length, and thus maximizing the number of times they meet…
2007-06-15
The article gives a check list of what one should know before walking a belt conveyor, and what to do during the walk. It then presents a list of what to look at on a walk along the conveyor system (excluding related equipment which could be inspected or maintained during the walk). It gives advice on when to stop the conveyor, on testing the emergency stop system, on recording problems and on acting on things noted. 1 tab.
Snakes and perturbed random walks
Basak, Gopal
2011-01-01
In this paper we study some properties of random walks perturbed at extrema, which are generalizations of the walks considered e.g., in Davis (1999). This process can also be viewed as a version of {\\em excited random walk}, studied recently by many authors. We obtain a few properties related to the range of the process with infinite memory. We also prove the Strong law, Central Limit Theorem, and the criterion for the recurrence of the perturbed walk with finite memory.
Area Restaurant Guide Walking Distance
Dyer, Bill
Area Restaurant Guide Walking Distance The Bozeman Deli College St.. (406) 587-2156 Location: 5 minute walk north of the SUB off the intersection of 9th and College St. Style of food: Variety-9137 Location: 5 minute walk north of the SUB and tucked behind Joe's Parkway on 9th Ave. Style of food: Mexican
10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.
Code of Federal Regulations, 2010 CFR
2010-01-01
...concerning walk-in coolers and walk-in freezers. 431.302 Section 431.302... Walk-in Coolers and Walk-in Freezers § 431.302 Definitions concerning walk-in coolers and walk-in freezers. Walk-in cooler and...
ERIC Educational Resources Information Center
Renfroe, Mark; Letendre, Wanda
1996-01-01
Describes a seventh-grade class project where students constructed a "time tunnel" (a walk-through display with models and exhibits illustrating various themes and eras). Beginning modestly, the tunnel grew over seven years to include 11 different display scenes. Discusses the construction of the project and benefits to the school. (MJP)
ERIC Educational Resources Information Center
Shen, Ji
2009-01-01
In the Walking Out Graphs Lesson described here, students experience several types of representations used to describe motion, including words, sentences, equations, graphs, data tables, and actions. The most important theme of this lesson is that students have to understand the consistency among these representations and form the habit of…
NSDL National Science Digital Library
The representation depicts a virtual walk through a Virginia forest to examine the impact of a non-native, invasive insect, the hemlock woolly adelgid, on a population of eastern hemlocks. Field research is conducted using the same scientific methodologies and tools that Smithsonian scientists use to monitor forest biodiversity, including scatter graph comparisons and field observations.
Deterministic Walks with Choice
Beeler, Katy E.; Berenhaut, Kenneth S.; Cooper, Joshua N.; Hunter, Meagan N.; Barr, Peter S.
2014-01-10
This paper studies deterministic movement over toroidal grids, integrating local information, bounded memory and choice at individual nodes. The research is motivated by recent work on deterministic random walks, and applications in multi-agent systems. Several results regarding passing tokens through toroidal grids are discussed, as well as some open questions.
ERIC Educational Resources Information Center
Schuster, Dwight
2008-01-01
Physical models in the classroom "cannot be expected to represent the full-scale phenomenon with complete accuracy, not even in the limited set of characteristics being studied" (AAAS 1990). Therefore, by modifying a popular classroom activity called a "planet walk," teachers can explore upper elementary students' current understandings; create an…
ERIC Educational Resources Information Center
Greenslade, Cleo B.
1988-01-01
Discusses a walking trip through Elfers, Florida, which gives intermediate level students a basis for a real understanding of the state's history, climate, economy, and natural resources. Describes how students prepare for the outing by examining maps and interviewing their parents and grandparents about life when they were in school. (GEA)
T. McGeer
1990-01-01
It is shown that passive dynamic walking, a phenomenon originally described for bipeds having straight legs, also works with knees. Thus, giving only a downhill slope as a source of energy, a human-like pair of legs will settle into a natural gait generated by the passive interaction of gravity and inertia. No muscular input is required. The physics is much
Walking lessons from orangutans
NSDL National Science Digital Library
American Association for the Advancement of Science (AAAS; )
2007-06-01
A group of scientists in the United Kingdom now have a different idea of how we came to walk on two legs. They got their idea from watching wild orangutans, who spend almost their whole lives in the trees of the rainforest.
ERIC Educational Resources Information Center
Kriesberg, Daniel
2001-01-01
Offers reminders and tips for improving interpretive walks, including having a theme, drawing on basic teaching methods, drawing on all senses rather than just talking, being a role model to show how learning can be fun, using picture books, using tools of the trade to encourage visitors to learn for themselves, and playing games. (PVD)
ERIC Educational Resources Information Center
Salia, Hannah
2010-01-01
The Walking in My Shoes curriculum at St. Thomas School in Medina, Washington, has been developed to deepen students' understanding of their own heritage and the cultural similarities and differences among their global peers. Exploring the rich diversity of the world's cultural heritage and the interactions of global migrations throughout history,…
ERIC Educational Resources Information Center
Turner, Jane
1998-01-01
Exploration of a specific use of Text Based Virtual Reality--not just as powerful communities for authentic communication and collaboration in language learning but exploiting role-playing and writing aspects. The "Walk on Ice" takes a group of adult English-as-a-Second-Language learners through the creation of imaginary characters who interact in…
Unitary Equivalence of Quantum Walks
Sandeep K Goyal; Thomas Konrad; Lajos Diósi
2014-12-03
A simple coined quantum walk in one dimension can be characterized by a $SU(2)$ operator with three parameters which represents the coin toss. However, different such coin toss operators lead to equivalent dynamics of the quantum walker. In this manuscript we present the unitary equivalence classes of quantum walks and show that all the nonequivalent quantum walks can be distinguished by a single parameter. Moreover, we argue that the electric quantum walks are equivalent to quantum walks with time dependent coin toss operator.
[Walking abnormalities in children].
Segawa, Masaya
2010-11-01
Walking is a spontaneous movement termed locomotion that is promoted by activation of antigravity muscles by serotonergic (5HT) neurons. Development of antigravity activity follows 3 developmental epochs of the sleep-wake (S-W) cycle and is modulated by particular 5HT neurons in each epoch. Activation of antigravity activities occurs in the first epoch (around the age of 3 to 4 months) as restriction of atonia in rapid eye movement (REM) stage and development of circadian S-W cycle. These activities strengthen in the second epoch, with modulation of day-time sleep and induction of crawling around the age of 8 months and induction of walking by 1 year. Around the age of 1 year 6 months, absence of guarded walking and interlimb cordination is observed along with modulation of day-time sleep to once in the afternoon. Bipedal walking in upright position occurs in the third epoch, with development of a biphasic S-W cycle by the age of 4-5 years. Patients with infantile autism (IA), Rett syndrome (RTT), or Tourette syndrome (TS) show failure in the development of the first, second, or third epoch, respectively. Patients with IA fail to develop interlimb coordination; those with RTT, crawling and walking; and those with TS, walking in upright posture. Basic pathophysiology underlying these condition is failure in restricting atonia in REM stage; this induces dysfunction of the pedunculopontine nucleus and consequently dys- or hypofunction of the dopamine (DA) neurons. DA hypofunction in the developing brain, associated with compensatory upward regulation of the DA receptors causes psychobehavioral disorders in infancy (IA), failure in synaptogenesis in the frontal cortex and functional development of the motor and associate cortexes in late infancy through the basal ganglia (RTT), and failure in functional development of the prefrontal cortex through the basal ganglia (TS). Further, locomotion failure in early childhood causes failure in development of functional specialization of the cortex through the spinal stepping generator-fastigial nucleus-thalamus-cortex pathway. Early detection of locomotion failure and early adjustment of this condition through environmental factors can prevent the development of higher cortical dysfunction. PMID:21068458
Relativistic Weierstrass random walks.
Saa, Alberto; Venegeroles, Roberto
2010-08-01
The Weierstrass random walk is a paradigmatic Markov chain giving rise to a Lévy-type superdiffusive behavior. It is well known that special relativity prevents the arbitrarily high velocities necessary to establish a superdiffusive behavior in any process occurring in Minkowski spacetime, implying, in particular, that any relativistic Markov chain describing spacetime phenomena must be essentially Gaussian. Here, we introduce a simple relativistic extension of the Weierstrass random walk and show that there must exist a transition time t{c} delimiting two qualitative distinct dynamical regimes: the (nonrelativistic) superdiffusive Lévy flights, for t
NSDL National Science Digital Library
The famous Walking Tour series on WNET, New York's public television station went to Newark, New Jersey, for the first tour outside of New York. Visitors who missed the show, or prefer a more interactive experience, will definitely enjoy the walking tour via the website. The two hosts of the tour, historian Barry Lewis, and former morning show host David Hartman, give visitors a multimedia tour which starts with a video clip in the "About the Program" link. Visitors will find that the "History of Newark" link is divided into four time periods, including "Colonial Founding", "Industrial Revolution", and "The Riots". The "See the Sites" link offers a more interactive approach for visitors to get to know Newark. There are 360-degree virtual tours of "Penn Station Newark", "Trinity Church" and "Military Park" on the left hand side of the page, and a map with 21 hotspots on it of Newark's "best landmarks and areas".
Mads T. Frandsen
2007-10-23
I report on our construction and analysis of the effective low energy Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of the effective Lagrangian are constrained by imposing modified Weinberg sum rules and by imposing a value for the S parameter estimated from the underlying Technicolor theory. The constrained effective Lagrangian allows for an inverted vector vs. axial-vector mass spectrum in a large part of the parameter space.
NSDL National Science Digital Library
Dwight Schuster
2008-09-01
Physical models in the classroom "cannot be expected to represent the full-scale phenomenon with complete accuracy, not even in the limited set of characteristics being studied" (AAAS 1990). Therefore, by modifying a popular classroom activity called a "planet walk," teachers can explore upper elementary students' current understandings; create an environment where students generate questions based on their prior knowledge; and challenge students to think critically about the accuracy and limitations of a scale model of our solar system.
NSDL National Science Digital Library
Huxley, Sophie.
1969-12-31
Maintained by The Museum of the History of Science, the Oxford Virtual Science Walk Web site explores "some of the most important and interesting historic scientific sites in Oxford, from the time of the founding of the University in the 13th century and the work of Friar Bacon to advancements in modern science such as the development of penicillin." Visitors visit thirteen sites and view an illustration of each along with a short but informative description.
NSDL National Science Digital Library
Miller, Bob
Artist Bob Miller's "Light Walk" at the Exploratorium is always an eye-opening experience for students and teachers alike. His unique discoveries will change the way you look at light, shadow, and images. The author includes activities such as doing your own lightwalk, building a pinhole viewer, building a pinhole camera, and slide projector activities. The author also provides an additional bibliography that is accompanied by reading materials. External links to related internet resources are also provided.
Borwein, Jonathan
Three movies Who we are Randomness Random walks Number walks base four Seeing walks on numbers References Seeing Things by Walking on Real Numbers Jonathan Borwein FRSC FAAS FAA FBAS (Joint work: City of the Future Revised 03-04 2004 Borwein and AragÂ´on (University of Newcastle, Australia) Walking
10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.
Code of Federal Regulations, 2014 CFR
2014-01-01
... Definitions concerning walk-in coolers and walk-in freezers. 431.302...AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers § 431.302 Definitions concerning walk-in coolers and walk-in freezers. Basic...
Hirofumi Miura; Isao Shimoyama
1984-01-01
The authors have developed five kinds of biped locomotive robots so far. They are named BIPER-1, 2, 3, 4, and 5. All of them are statically unstable but can perform a dynamically stable walk with suitable control. BIPER-1 and BIPER-2 walk only sideways. BIPER-3 is a stilt-type robot whose foot contacts occur at a point and who can walk sideways,
Quantum Walks with Entangled Coins
S. E. Venegas-Andraca; J. L. Ball; K. Burnett; S. Bose
2005-10-18
We present a mathematical formalism for the description of unrestricted quantum walks with entangled coins and one walker. The numerical behaviour of such walks is examined when using a Bell state as the initial coin state, two different coin operators, two different shift operators, and one walker. We compare and contrast the performance of these quantum walks with that of a classical random walk consisting of one walker and two maximally correlated coins as well as quantum walks with coins sharing different degrees of entanglement. We illustrate that the behaviour of our walk with entangled coins can be very different in comparison to the usual quantum walk with a single coin. We also demonstrate that simply by changing the shift operator, we can generate widely different distributions. We also compare the behaviour of quantum walks with maximally entangled coins with that of quantum walks with non-entangled coins. Finally, we show that the use of different shift operators on 2 and 3 qubit coins leads to different position probability distributions in 1 and 2 dimensional graphs.
A relativistically covariant random walk
NASA Astrophysics Data System (ADS)
Almaguer, J.; Larralde, H.
2007-08-01
In this work we present and analyze an extremely simple relativistically covariant random walk model. In our approach, the probability density and the flow of probability arise naturally as the components of a four-vector and they are related to one another via a tensorial constitutive equation. We show that the system can be described in terms of an underlying invariant space time random walk parameterized by the number of sojourns. Finally, we obtain explicit expressions for the moments of the covariant random walk as well as for the underlying invariant random walk.
Quantum Walks on the Hypercube
Cristopher Moore; Alexander Russell
2001-04-29
Recently, it has been shown that one-dimensional quantum walks can mix more quickly than classical random walks, suggesting that quantum Monte Carlo algorithms can outperform their classical counterparts. We study two quantum walks on the n-dimensional hypercube, one in discrete time and one in continuous time. In both cases we show that the quantum walk mixes in (\\pi/4)n steps, faster than the O(n log n) steps required by the classical walk. In the continuous-time case, the probability distribution is {\\em exactly} uniform at this time. More importantly, these walks expose several subtleties in the definition of mixing time for quantum walks. Even though the continuous-time walk has an O(n) instantaneous mixing time at which it is precisely uniform, it never approaches the uniform distribution when the stopping time is chosen randomly as in [AharonovAKV2001]. Our analysis treats interference between terms of different phase more carefully than is necessary for the walk on the cycle; previous general bounds predict an exponential, rather than linear, mixing time for the hypercube.
Bartsch, Christian; Kochler, Thomas; Müller, Sebastian; Popov, Serguei
2011-01-01
We consider a branching random walk on $\\Z$, where the particles behave differently in visited and unvisited sites. Informally, each site on the positive half-line contains initially a cookie. On the first visit of a site its cookie is removed and particles at positions with a cookie reproduce and move differently from particles on sites without cookies. Therefore, the movement and the reproduction of the particles depend on the previous behaviour of the population of particles. We study the question if the process is recurrent or transient, i.e., whether infinitely many particles visit the origin or not.
NASA Technical Reports Server (NTRS)
Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.
1990-01-01
Proposed walking-beam robot simpler and more rugged than articulated-leg walkers. Requires less data processing, and uses power more efficiently. Includes pair of tripods, one nested in other. Inner tripod holds power supplies, communication equipment, computers, instrumentation, sampling arms, and articulated sensor turrets. Outer tripod holds mast on which antennas for communication with remote control site and video cameras for viewing local and distant terrain mounted. Propels itself by raising, translating, and lowering tripods in alternation. Steers itself by rotating raised tripod on turntable.
NASA Technical Reports Server (NTRS)
Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.
1990-01-01
Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.
NSDL National Science Digital Library
This BBC Web site comes loaded with interactive multimedia features on evolution and the animal kingdom. Users can view 3-D images as well as video and audio clips of prehistoric creatures, play an interactive evolution game, and much more. The Web site also includes dozens of comprehensive, downloadable lessons plans and worksheets for students age 7-14 (click on Teachers to access these materials). The lesson plans encourage offline investigation and problem solving, but also provide links to relevant features within the Walking with Beasts Web site. The use of certain online features, with their engaging visuals and interactive design, should make these lesson plans especially appealing to students.
Science Sampler: The Element Walk
NSDL National Science Digital Library
Dennis Smithenry
2009-10-01
"The Element Walk" lesson is effective at teaching students the elements that exist in common substances encountered every day. Students walk away from the lesson with a set of general rules that help them to easily identify the elements around them. They
RANDOM WALK AND HYPERPLANE ARRANGEMENTS
Kenneth S. Brown; Persi Diaconis
1998-01-01
LetC be the set of chambers of a real hyperplane arrangement. We study a random walk on C introduced by Bidigare, Hanlon, and Rockmore. This includes various shu†ing schemes used in computer science, biology, and card games. It also includes random walks on zonotopes and zonotopal tilings. We flnd the stationary distributions of these Markov chains, give good bounds on
Quantum Random Walks and Thermalisation
NASA Astrophysics Data System (ADS)
Belton, Alexander C. R.
2010-12-01
It is shown how to construct quantum random walks with particles in an arbitrary faithful normal state. A convergence theorem is obtained for such walks, which demonstrates a thermalisation effect: the limit cocycle obeys a quantum stochastic differential equation without gauge terms. Examples are presented which generalise that of Attal and Joye (J Funct Anal 247:253-288, 2007).
Quantum walks on quotient graphs
Krovi, Hari; Brun, Todd A.
2007-06-15
A discrete-time quantum walk on a graph {gamma} is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup H of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup H used to construct it. The quotient graph is constructed by removing the symmetries of the subgroup H from the original graph. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A 74, 042334 (2006)] that the hitting time for certain initial states of a quantum walks can be infinite, in contrast to classical random walks. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with hitting times which are short compared to classical random walks correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speedup.
Borwein, Jonathan
Introduction Randomness Normality Random walks Features of random walks Other tools & representations Seeing Things by Walking on Real Numbers Jonathan Borwein FRSC FAAS FAA FBAS (Joint work Sydney, October 2013 Revised 16-09-2013 Borwein and AragÂ´on (University of Newcastle, Australia) Walking
NASA Astrophysics Data System (ADS)
Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.
2007-11-01
We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using high-speed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.
NASA Astrophysics Data System (ADS)
Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.
We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using highspeed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.
Erdmenger, Johanna; Halter, Sebastian; Núñez, Carlos; Tasinato, Gianmassimo E-mail: s.halter@physik.uni-muenchen.de E-mail: gianmassimo.tasinato@port.ac.uk
2013-01-01
We propose a new model of slow-roll inflation in string cosmology, based on warped throat supergravity solutions displaying 'walking' dynamics, i.e. the coupling constant of the dual gauge theory slowly varies over a range of energy scales. The features of the throat geometry are sourced by a rich field content, given by the dilaton and RR and NS fluxes. By considering the motion of a D3-brane probe in this geometry, we are able to analytically calculate the brane potential in a physically interesting regime. This potential has an inflection point: in its proximity we realize a model of inflation lasting sixty e-foldings, and whose robust predictions are in agreement with current observations. We are also able to interpret some of the most interesting aspects of this scenario in terms of the properties of the QFT dual theory.
Reduced Gravity Walking Simulator
NASA Technical Reports Server (NTRS)
1963-01-01
A test subject being suited up for studies on the Reduced Gravity Walking Simulator located in the hanger at Langley Research Center. The initial version of this simulator was located inside the hanger. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. Francis B. Smith wrote in his paper 'Simulators For Manned Space Research,' 'I would like to conclude this talk with a discussion of a device for simulating lunar gravity which is very effective and yet which is so simple that its cost is in the order of a few thousand dollars at most, rather than hundreds of thousands. With a little ingenuity, one could almost build this type simulator in his backyard for children to play on. The principle is ...if a test subject is suspended in a sling so that his body axis makes an angle of 9 1/2 degrees with the horizontal and if he then 'stands' on a platform perpendicular to his body axis, the component of the earth's gravity forcing him toward the platform is one times the sine of 9 1/2 degrees or approximately 1/6 of the earth's normal gravity field. That is, a 180 pound astronaut 'standing' on the platform would exert a force of only 30 pounds - the same as if he were standing upright on the lunar surface.' Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308; Francis B. Smith, 'Simulators For Manned Space Research,' Paper for 1966 IEEE International Convention, New York, NY, March 21-25, 1966.
Pratt, Gill Andrews
2002-02-01
For both historical and technological reasons, most robots, including those meant to mimic animals or operate in natural environments,3 use actuators and control systems that have high (stiff) mechanical impedance. By contrast, most animals exhibit low (soft) impedance. While a robot's stiff joints may be programmed to closely imitate the recorded motion of an animal's soft joints, any unexpected position disturbances will generate reactive forces and torques much higher for the robot than for the animal. The dual of this is also true: while an animal will react to a force disturbance by significantly yielding position, a typical robot will greatly resist.These differences cause three deleterious effects for high impedance robots. First, the higher forces may cause damage to the robot or to its environment (which is particularly important if that environment includes people). Second, the robot must acquire very precise information about its position relative to the environment so as to minimize its velocity upon impact. Third, many of the self-stabilizing effects of natural dynamics are "shorted out"4 by the robot's high impedance, so that stabilization requires more effort from the control system.Over the past 5 yr, our laboratory has designed a series of walking robots based on "Series-Elastic Actuators" and "Virtual Model Control." Using these two techniques, we have been able to build low-impedance walking robots that are both safe and robust, that operate blindly without any model of upcoming terrain, and that add minimal control effort in parallel to their self-stabilizing passive dynamics. We have discovered that it is possible to achieve surprisingly effective ambulation from rather simple mechanisms and control systems. After describing the historical and technological motivations for our approach, this paper gives an overview of our methods and shows some of the results we have obtained. PMID:21708707
Random walk with memory Ryszard Rudnicki
Wolf, Marek
-50-204 Wroclaw, Poland Received 16 June 1998, accepted for publication 17 November 1998 A reinforced-avoiding walk SAW for short , etc. Let us confine ourselves to the random walks on the discrete lattices. In SAW. In 1987 Coppersmith and Diaconis5 introduced reinforced random walk RRW . This walk, opposite to SAW
Analysis of absorbing times of quantum walks
Yamasaki, Tomohiro; Kobayashi, Hirotada; Imai, Hiroshi
2003-07-01
Quantum walks are expected to provide useful algorithmic tools for quantum computation. This paper introduces absorbing probability and time of quantum walks and gives both numerical simulation results and theoretical analyses on Hadamard walks on the line and symmetric walks on the hypercube from the viewpoint of absorbing probability and time.
Analysis of Absorbing Times of Quantum Walks
Tomohiro Yamasaki; Hirotada Kobayashi; Hiroshi Imai
2003-04-28
Quantum walks are expected to provide useful algorithmic tools for quantum computation. This paper introduces absorbing probability and time of quantum walks and gives both numerical simulation results and theoretical analyses on Hadamard walks on the line and symmetric walks on the hypercube from the viewpoint of absorbing probability and time.
The CyberWalk Platform: Human-Machine Interaction Enabling Unconstrained Walking through VR
The CyberWalk Platform: Human-Machine Interaction Enabling Unconstrained Walking through VR P would be to walk. For small scale virtual environments one can simply walk within a confined space locomotion interfaces already exist that allow walking in virtual environments (see, e.g., the surveys in [1
The effect of walking speed and avatars on Redirected Walking Master Thesis
The effect of walking speed and avatars on Redirected Walking Master Thesis Fakultät Informatik Abstract 5 1 Introduction 6 1.1 Related Work 8 1.1.1 The invention of Redirected Walking 9 1.1.2 Further advancements in Redirected Walking 9 1.1.3 Dynamic controller for Redirected Walking 10 1.1.4 Using distracters
S. D. Freedman; Y. H. Tong; J. B. Wang
2014-08-06
Quantum walks are expected to serve important modelling and algorithmic applications in many areas of science and mathematics. Although quantum walks have been successfully implemented physically in recent times, no major efforts have been made to combat the error associated with these physical implementations in a fault-tolerant manner. In this paper, we propose a systematic method to implement fault-tolerant quantum walks in discrete time on arbitrarily complex graphs, using quantum states encoded with the Steane code and a set of universal fault tolerant matrix operations.
Constraining Walking and Custodial Technicolor
Roshan Foadi; Mads T. Frandsen; Francesco Sannino
2007-12-12
We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level - custodial technicolor - and argue that these models cannot emerge from walking type dynamics. We suggest that it is possible to have a very light spin-one axial vector boson. However, in the walking dynamics the associated vector boson is heavy while it is degenerate with the axial in custodial technicolor.
Constraining walking and custodial technicolor
Foadi, Roshan; Frandsen, Mads T.; Sannino, Francesco [University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)
2008-05-01
We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level - custodial technicolor - and argue that these models cannot emerge from walking-type dynamics. We suggest that it is possible to have a very light spin-one axial (vector) boson. However, in the walking dynamics the associated vector boson is heavy while it is degenerate with the axial in custodial technicolor.
Distributions of continuous-time quantum walks
Arvid J. Bessen
2006-10-16
We study the distributions of the continuous-time quantum walk on a one-dimensional lattice. In particular we will consider walks on unbounded lattices, walks with one and two boundaries and Dirichlet boundary conditions, and walks with periodic boundary conditions. We will prove that all continuous-time quantum walks can be written as a series of Bessel functions of the first kind and show how to approximate these series.
Science Sampler: Walking Out Graphs
NSDL National Science Digital Library
Ji Shen
2009-12-01
In the Walking Out Graphs Lesson described here, students experience several types of representations used to describe motion, including words, sentences, equations, graphs, data tables, and actions. The most important theme of this lesson is that student
Ansis Rosmanis
2010-08-18
I introduce a new type of continuous-time quantum walk on graphs called the quantum snake walk, the basis states of which are fixed-length paths (snakes) in the underlying graph. First I analyze the quantum snake walk on the line, and I show that, even though most states stay localized throughout the evolution, there are specific states which most likely move on the line as wave packets with momentum inversely proportional to the length of the snake. Next I discuss how an algorithm based on the quantum snake walk might potentially be able to solve an extended version of the glued trees problem which asks to find a path connecting both roots of the glued trees graph. No efficient quantum algorithm solving this problem is known yet.
free campus shuttles Walking guide
Minnesota, University of
free campus shuttles Walking guide 2014-15 Twin ciTies Campus Security Escort Available n Trained University Ave. Ramp to Moos Tower 8 minutes Rec Center to Science Teaching & Student Services 7 minutes
Quantum walks on embedded hypercubes
NASA Astrophysics Data System (ADS)
Makmal, Adi; Zhu, Manran; Manzano, Daniel; Tiersch, Markus; Briegel, Hans J.
2014-08-01
It has been proved by Kempe that discrete quantum walks on the hypercube (HC) hit exponentially faster than the classical analog. The same was also observed numerically by Krovi and Brun for a slightly different property, namely, the expected hitting time. Yet, to what extent this striking result survives in more general graphs is to date an open question. Here, we tackle this question by studying the expected hitting time for quantum walks on HCs that are embedded into larger symmetric structures. By performing numerical simulations of the discrete quantum walk and deriving a general expression for the classical hitting time, we observe an exponentially increasing gap between the expected classical and quantum hitting times, not only for walks on the bare HC, but also for a large family of embedded HCs. This suggests that the quantum speedup is stable with respect to such embeddings.
Quantum walks on embedded hypercubes
Adi Makmal; Manran Zhu; Daniel Manzano; Markus Tiersch; Hans J. Briegel
2013-09-20
It has been proved by Kempe that discrete quantum walks on the hypercube (HC) hit exponentially faster than the classical analog. The same was also observed numerically by Krovi and Brun for a slightly different property, namely, the expected hitting time. Yet, to what extent this striking result survives in more general graphs, is to date an open question. Here we tackle this question by studying the expected hitting time for quantum walks on HCs that are embedded into larger symmetric structures. By performing numerical simulations of the discrete quantum walk and deriving a general expression for the classical hitting time, we observe an exponentially increasing gap between the expected classical and quantum hitting times, not only for walks on the bare HC, but also for a large family of embedded HCs. This suggests that the quantum speedup is stable with respect to such embeddings.
Walking Dynamics from String Duals
Carlos Nunez; Ioannis Papadimitriou; Maurizio Piai
2009-01-13
Within the context of a String Theory dual to N=1 gauge theories with gauge group SU(Nc) and large Nc, we identify a class of solutions of the background equations for which a suitably defined dual of the gauge coupling exhibits the features of a walking theory. We find evidence for three distinct, dynamically generated scales, characterizing walking, symmetry breaking and confinement, and we put them in correspondence with field theory by an analysis of the operators driving the flow.
Belyaev, Alexander; Foadi, Roshan; Frandsen, Mads T.; Jaervinen, Matti; Sannino, Francesco; Pukhov, Alexander [NExT Institute: School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom, and Particle Physics Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); High Energy Physics Center, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation)
2009-02-01
We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable walking technicolor models. We study and compare the Drell-Yan and vector boson fusion mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the Drell-Yan processes. The composite Higgs phenomenology is also studied. If technicolor walks at the LHC, its footprints will be visible and our analysis will help in uncovering them.
Walking Behavior in Technicolored GUTs
A. Doff
2009-02-19
There exist two ways to obtain walk behavior: assuming a large number of technifermions in the fundamental representation of the technicolor (TC) gauge group, or a small number of technifermions, assuming that these fermions are in higher-dimensional representations of the TC group. We propose a scheme to obtain the walking behavior based on technicolored GUTs (TGUTs), where elementary scalars with the TC degree of freedom may remain in the theory after the GUT symmetry breaking.
C. Anteneodo
2005-01-01
Stochastic variables whose addition leads to q-Gaussian distributions Gq(x)?[1+(q-1)?x2]+1\\/(1-q) (with ?>0, 1?q3 and where [f(x)]+=max{f(x),0}) as limit law for a large number of terms are investigated. Random walk sequences related to this problem possess a simple additive–multiplicative structure commonly found in several contexts, thus justifying the ubiquity of those distributions. A characterization of the statistical properties of the random walk
A. Belyaev; R. Foadi; M. T. Frandsen; M. Jarvinen; A. Pukhov; F. Sannino
2008-09-04
We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable Walking Technicolor models. We study and compare the Drell-Yan (DY) and Vector Boson Fusion (VBF) mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the DY processes. The composite Higgs phenomenology is also studied. If Technicolor walks at the LHC its footprints will be visible and our analysis will help uncovering them.
Belyaev, A; Frandsen, M T; Jarvinen, M; Pukhov, A; Sannino, F
2008-01-01
We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable Walking Technicolor models. We study and compare the Drell-Yan (DY) and Vector Boson Fusion (VBF) mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the DY processes. The composite Higgs phenomenology is also studied. If Technicolor walks at the LHC its footprints will be visible and our analysis will help uncovering them.
Coins Make Quantum Walks Faster
Andris Ambainis; Julia Kempe; Alexander Rivosh
2004-02-16
We show how to search N items arranged on a $\\sqrt{N}\\times\\sqrt{N}$ grid in time $O(\\sqrt N \\log N)$, using a discrete time quantum walk. This result for the first time exhibits a significant difference between discrete time and continuous time walks without coin degrees of freedom, since it has been shown recently that such a continuous time walk needs time $\\Omega(N)$ to perform the same task. Our result furthermore improves on a previous bound for quantum local search by Aaronson and Ambainis. We generalize our result to 3 and more dimensions where the walk yields the optimal performance of $O(\\sqrt{N})$ and give several extensions of quantum walk search algorithms for general graphs. The coin-flip operation needs to be chosen judiciously: we show that another ``natural'' choice of coin gives a walk that takes $\\Omega(N)$ steps. We also show that in 2 dimensions it is sufficient to have a two-dimensional coin-space to achieve the time $O(\\sqrt{N} \\log N)$.
Coins Make Quantum Walks Faster
Ambainis, A; Rivosh, A; Ambainis, Andris; Kempe, Julia; Rivosh, Alexander
2004-01-01
We show how to search N items arranged on a $\\sqrt{N}\\times\\sqrt{N}$ grid in time $O(\\sqrt N \\log N)$, using a discrete time quantum walk. This result for the first time exhibits a significant difference between discrete time and continuous time walks without coin degrees of freedom, since it has been shown recently that such a continuous time walk needs time $\\Omega(N)$ to perform the same task. Our result furthermore improves on a previous bound for quantum local search by Aaronson and Ambainis. We generalize our result to 3 and more dimensions where the walk yields the optimal performance of $O(\\sqrt{N})$ and give several extensions of quantum walk search algorithms for general graphs. The coin-flip operation needs to be chosen judiciously: we show that another ``natural'' choice of coin gives a walk that takes $\\Omega(N)$ steps. We also show that in 2 dimensions it is sufficient to have a two-dimensional coin-space to achieve the time $O(\\sqrt{N} \\log N)$.
Portable walking beam pump jack
Laney, R.N.
1986-02-25
This patent describes a portable walking beam pump jack for use in pumping liquids from an oil well. This jack consists of: an elongated frame having a longitudinal axis and front and rear ends, the frame also including first and second support seats; a towing receptacle, an axle connected transversely across the frame; ground engaging wheels connected to the axle for supporting the frame for rolling transportation; stabilizing means for securing the frame with respect to a ground location; a walking beam having a first end, a midportion and a second end, the second end being adapted for connection to a pumping rod; an engine mounted on the frame; a pair of arms counterweighted for balancing a pumping rod connected to the walking beam, a drive yoke, a support assembly foldably mounted on the frame and upon which the midportion of the walking beam is pivotally connected, the support assembly the arms and the drive yoke being foldable together, from a first, fixed position in which the walking beam arms and yoke are supported in a raised position for rocking in a pumping motion to a second, fixed position disposed downwardly and forwardly from the first fixed position and in which the walking beam arms and yoke are held in a lowered position for transportation; a front support and a hydraulic cylinder connected between the frame and the support assembly for moving the support assembly between the first, fixed position and the second fixed position.
Walk Score® and Transit Score® and Walking in the Multi-Ethnic Study of Atherosclerosis
Hirsch, Jana A.; Moore, Kari A.; Evenson, Kelly R.; Rodriguez, Daniel A; Diez Roux, Ana V.
2013-01-01
Background Walk Score® and Transit Score® are open-source measures of the neighborhood built environment to support walking (“walkability”) and access to transportation. Purpose To investigate associations of Street Smart Walk Score and Transit Score with self-reported transport and leisure walking using data from a large multi-city and diverse population-based sample of adults. Methods Data from a sample of 4552 residents of Baltimore MD; Chicago IL; Forsyth County NC; Los Angeles CA; New York NY; and St. Paul MN from the Multi-Ethnic Study of Atherosclerosis (2010–2012) were linked to Walk Score and Transit Score (collected in 2012). Logistic and linear regression models estimated ORs of not walking and mean differences in minutes walked, respectively, associated with continuous and categoric Walk Score and Transit Score. All analyses were conducted in 2012. Results After adjustment for site, key sociodemographic, and health variables, a higher Walk Score was associated with lower odds of not walking for transport and more minutes/week of transport walking. Compared to those in a “walker’s paradise,” lower categories of Walk Score were associated with a linear increase in odds of not transport walking and a decline in minutes of leisure walking. An increase in Transit Score was associated with lower odds of not transport walking or leisure walking, and additional minutes/week of leisure walking. Conclusions Walk Score and Transit Score appear to be useful as measures of walkability in analyses of neighborhood effects. PMID:23867022
H. Lavi?ka; V. Poto?ek; T. Kiss; E. Lutz; I. Jex
2011-06-20
We analyze a special class of 1-D quantum walks (QWs) realized using optical multi-ports. We assume non-perfect multi-ports showing errors in the connectivity, i.e. with a small probability the multi- ports can connect not to their nearest neighbor but to another multi-port at a fixed distance - we call this a jump. We study two cases of QW with jumps where multiple displacements can emerge at one timestep. The first case assumes time-correlated jumps (static disorder). In the second case, we choose the positions of jumps randomly in time (dynamic disorder). The probability distributions of position of the QW walker in both instances differ significantly: dynamic disorder leads to a Gaussian-like distribution, while for static disorder we find two distinct behaviors depending on the parity of jump size. In the case of even-sized jumps, the distribution exhibits a three-peak profile around the position of the initial excitation, whereas the probability distribution in the odd case follows a Laplace-like discrete distribution modulated by additional (exponential) peaks for long times. Finally, our numerical results indicate that by an appropriate mapping an universal functional behavior of the variance of the long-time probability distribution can be revealed with respect to the scaled average of jump size.
Walking with Prehistoric Beasts
NSDL National Science Digital Library
2001-01-01
Nope, it's not about dinosaurs but it is just as fascinating! "Walking with Prehistoric Beasts is the Discovery Channel's new television series on the creatures that inhabited Earth after the dinosaurs disappeared 65 million years ago (mya). The program's companion Website offers fabulous graphics and games, with a little bit of informative text mixed in, about such beasts as Gastornis, a meat-loving bird the size of a tall human, Propalaeotherium, a 43 million year old cat-sized horse, and Andrewsarchus, a furry, land-dwelling ancestor of the whale. Facts on pronunciation, etymology, geologic time range, body size, diet, geographic range and closest living relative are given for every animal in the Beast Gallery. When visiting this site you should not miss the How do We Know section, housing audio recordings of paleontologists answering your e.mail questions (Real/Windows Media) or the Changing Worlds game in which players control a map of Earth showing vegetation, mammal life and ocean currents from 65 mya to present. Plus, you can test your beast-mastery with the Beastly Quiz.
Quantum walks based on an interferometric analogy
Hillery, Mark; Bergou, Janos [Department of Physics, Hunter College of CUNY, 695 Park Avenue, New York, New York 10021, USA (United States); Feldman, Edgar [Department of Mathematics, Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, USA (United States)
2003-09-01
There are presently two models for quantum walks on graphs. The ''coined'' walk uses discrete-time steps, and contains, besides the particle making the walk, a second quantum system, the coin, that determines the direction in which the particle will move. The continuous walk operates with continuous time. Here a third model for quantum walks is proposed, which is based on an analogy to optical interferometers. It is a discrete-time model, and the unitary operator that advances the walk one step depends only on the local structure of the graph on which the walk is taking place. This type of walk also allows us to introduce elements, such as phase shifters, that have no counterpart in classical random walks. Several examples are discussed.
Quantum walks on quotient graphs
Hari Krovi; Todd A. Brun
2007-01-23
A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup used to construct it. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A {\\bf 74}, 042334 (2006)] that the hitting time can be infinite. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with fast hitting times correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speed-up.
Persistent personal biases in walking.
Boeddeker, Norbert; Jetzschke, Simon; Ernst, Marc
2015-09-01
Locomotion along a given path in the absence of vision and audition is known to be inaccurate. Here we ask about the nature of these inaccuracies. To this end, we analyzed the performance of participants in three walking experiments involving straight and angle-walking tasks. In the first experiment eight blindfolded participants were guided along paths of different lengths and asked to turn to a target location by an angle of ±90° in a sports hall (size: 25x45m). We found significant biases in turn angles, i.e. systematic deviations from the correct angle that were characteristic of certain participants, whereas varying path length had weak effects on turn accuracy and precision. To check whether this idiosyncrasy was persistent over time and present in another type of walking task, we performed a second experiment several weeks after the first. Here, the same participants were guided to walk turns with varying amplitude. We then asked them to judge whether they had walked an angle larger or smaller than 90° in a two-alternative forced-choice (2AFC) paradigm. Very surprisingly, the personal bias was highly correlated between the two experiments indicating that the sense of direction can be persistently and individually biased in the absence of external directional cues. In a third experiment the participants where asked to walk straight on slanted and level surfaces. Here, we again found persistent directional biases in most participants. The direction of surface inclination did not significantly influence these individual biases. We found systematic angular biases in several walking tasks that were persistent over weeks. The biases reported here for healthy participants are most likely counterbalanced during normal daily-life by using visual and auditory cues for spatial orientation. Meeting abstract presented at VSS 2015. PMID:26327013
Correlated Markov Quantum Walks
Eman Hamza; Alain Joye
2011-10-21
We consider the discrete time unitary dynamics given by a quantum walk on $\\Z^d$ performed by a particle with internal degree of freedom, called coin state, according to the following iterated rule: a unitary update of the coin state takes place, followed by a shift on the lattice, conditioned on the coin state of the particle. We study the large time behavior of the quantum mechanical probability distribution of the position observable in $\\Z^d$ for random updates of the coin states of the following form. The random sequences of unitary updates are given by a site dependent function of a Markov chain in time, with the following properties: on each site, they share the same stationnary Markovian distribution and, for each fixed time, they form a deterministic periodic pattern on the lattice. We prove a Feynman-Kac formula to express the characteristic function of the averaged distribution over the randomness at time $n$ in terms of the nth power of an operator $M$. By analyzing the spectrum of $M$, we show that this distribution posesses a drift proportional to the time and its centered counterpart displays a diffusive behavior with a diffusion matrix we compute. Moderate and large deviations principles are also proven to hold for the averaged distribution and the limit of the suitably rescaled corresponding characteristic function is shown to satisfy a diffusion equation. An example of random updates for which the analysis of the distribution can be performed without averaging is worked out. The random distribution displays a deterministic drift proportional to time and its centered counterpart gives rise to a random diffusion matrix whose law we compute. We complete the picture by presenting an uncorrelated example.
Noisy continuous time random walks
NASA Astrophysics Data System (ADS)
Jeon, Jae-Hyung; Barkai, Eli; Metzler, Ralf
2013-09-01
Experimental studies of the diffusion of biomolecules within biological cells are routinely confronted with multiple sources of stochasticity, whose identification renders the detailed data analysis of single molecule trajectories quite intricate. Here, we consider subdiffusive continuous time random walks that represent a seminal model for the anomalous diffusion of tracer particles in complex environments. This motion is characterized by multiple trapping events with infinite mean sojourn time. In real physical situations, however, instead of the full immobilization predicted by the continuous time random walk model, the motion of the tracer particle shows additional jiggling, for instance, due to thermal agitation of the environment. We here present and analyze in detail an extension of the continuous time random walk model. Superimposing the multiple trapping behavior with additive Gaussian noise of variable strength, we demonstrate that the resulting process exhibits a rich variety of apparent dynamic regimes. In particular, such noisy continuous time random walks may appear ergodic, while the bare continuous time random walk exhibits weak ergodicity breaking. Detailed knowledge of this behavior will be useful for the truthful physical analysis of experimentally observed subdiffusion.
Walking on ballast impacts balance.
Wade, Chip; Garner, John C; Redfern, Mark S; Andres, Robert O
2014-01-01
Railroad workers often perform daily work activities on irregular surfaces, specifically on ballast rock. Previous research and injury epidemiology have suggested a relationship between working on irregular surfaces and postural instability. The purpose of this study was to examine the impact of walking on ballast for an extended duration on standing balance. A total of 16 healthy adult males walked on a 7.62 m × 4.57 m (25 ft × 15 ft) walking surface of no ballast (NB) or covered with ballast (B) of an average rock size of about 1 inch for 4 h. Balance was evaluated using dynamic posturography with the NeuroCom(®) Equitest System(™) prior to experiencing the NB or B surface and again every 30 min during the 4 h of ballast exposure. Dependent variables were the sway velocity and root-mean-square (RMS) sway components in the medial-lateral and anterior-posterior directions. Repeated measures ANOVA revealed statistically significant differences in RMS and sway velocity between ballast surface conditions and across exposure times. Overall, the ballast surface condition induced greater sway in all of the dynamic posturography conditions. Walking on irregular surfaces for extended durations has a deleterious effect on balance compared to walking on a surface without ballast. These findings of changes in balance during ballast exposure suggest that working on an irregular surface may impact postural control. PMID:24354716
Random walk with barycentric self-interaction Andrew Wade
Wirosoetisno, Djoko
to nonhomogeneous random walk 3 Random walk models of polymer chains 4 Random walk with barycentric self of examples is provided by centrally biased random walks. · A concrete example: For x Rd , let b1(x
How to Build a Walking Trail Texas Department of Health
How to Build a Walking Trail Texas Department of Health Chronic Disease Community & Worksite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Walking Trail Materials--Chapter 3 Surface Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Walking Trail Signs--Chapter 4 Walking Trail Signs
KidsWalk-to-School: A Guide To Promote Walking to School.
ERIC Educational Resources Information Center
Center for Chronic Disease Prevention and Health Promotion (DHHS/CDC), Atlanta, GA.
This guide encourages people to create safe walking and biking routes to school, promoting four issues: physically active travel, safe and walkable routes to school, crime prevention, and health environments. The chapters include: "KidsWalk-to-School: A Guide to Promote Walking to School" (Is there a solution? Why is walking to school important?…
A Walking School Bus Program Increased Students' Walking to School and Decreased Transport by Car
Technology Transfer Automated Retrieval System (TEKTRAN)
Walking school buses are popular programs designed to overcome barriers and increase the numbers of children who walk to school. We tested the hypothesis that a walking school bus program would increase the proportion of children walking to school and decrease the proportion transported to school by...
Walking > Walking-in-Place > Flying, in Virtual Environments Martin Usoh
Slater, Mel
Walking > Walking-in-Place > Flying, in Virtual Environments Martin Usoh Kevin Arthur Mary C environment experience a higher subjective sense of presence when they locomote by walking-in-place (virtual walking) than when they push-button-fly (along the floor plane). We replicated their study, adding real
Foot placement in a body reference frame during walking and its relationship to hemiparetic walking Keywords: Walking Biomechanics Foot placement Stroke Spatiotemporal parameters a b s t r a c t Background: Foot placement during walking is closely linked to the body position, yet it is typically quantified
Optimal speeds for walking and running, and walking on a moving walkway
Srinivasan, Manoj
Optimal speeds for walking and running, and walking on a moving walkway Manoj Srinivasana of walking on moving walkways, such as those found in some airports. First, I describe two possible at which people and horses prefer to walk naturally. Minimizing the net cost per distance is equivalent
TESTING OF THE FE WALKING ROBOT MAY 2006 1 Testing of the FE Walking Robot
Ruina, Andy L.
TESTING OF THE FE WALKING ROBOT MAY 2006 1 Testing of the FE Walking Robot Elianna R Weyer, May and result of testing the FE walking robot during spring 2006. Improve- ments in code and launch technique. The author predicts that with continued optimization and testing, the FE walking robot can surpass
Random Walks and Electrical Networks Electrical Network Calculations in Random Walks in
Peterson, Jonathon
Random Walks and Electrical Networks Electrical Network Calculations in Random Walks in Random 2/4/2008 1 / 23 #12;Random Walks and Electrical Networks Much of this talk is based on the book Random Walks and Electric Networks by Peter G. Doyle and J. Laurie Snell. Free download available at http
The Recovery of Walking in Stroke Patients: A Review
ERIC Educational Resources Information Center
Jang, Sung Ho
2010-01-01
We reviewed the literature on walking recovery of stroke patients as it relates to the following subjects: epidemiology of walking dysfunction, recovery course of walking, and recovery mechanism of walking (neural control of normal walking, the evaluation methods for leg motor function, and motor recovery mechanism of leg). The recovery of walking…
Cool Walking: A New Markov Chain Monte Carlo Sampling Method
Head-Gordon, Teresa L.
Cool Walking: A New Markov Chain Monte Carlo Sampling Method SCOTT BROWN, TERESA HEAD for overcoming quasi-ergodicity problems such as Jump Walking (J-Walking), Smart Walking (S-Walking), Smart Darting, and Parallel Tempering. We present an alternative to these approaches that we call Cool Walking
NSDL National Science Digital Library
NASA Johnson Space Center
2012-06-26
In this activity, learners will train to improve lung, heart, and other muscle endurance as they walk a progressive, measured distance. Learners measure out a course according to specific distances, walk/jog/run the distance, and record and graph their observations. This activity simulates how astronauts must train before missions in order to build up the endurance required to move in space. An embedded video on this page showcases the activity. Learners can complete this activity as part of NASA's Fit Explorer Challenge, in which learners train like astronauts, set goals, track their progress, and accumulate points to progress through Exploration Levels and earn certificates.
After Talking the Talk, Now Walk the Walk
ERIC Educational Resources Information Center
Vukovic, Paul
2011-01-01
In this article, the author describes what his students are doing following the ATM Easter conference in Telford, where he was inspired by a workshop entitled "Vitamin D Maths," conducted by Jocelyn D'Arcy. He describes an activity that allows his Year 11 students to walk through angles drawn on the floors. This topic will now literally be given a…
Markov Random Walk Representations with Continuous Distributions
Yeang, Chen-Hsiang
Markov Random Walk Representations with Continuous Distributions Chen-Hsiang Yeang MIT Artificial Cambridge, UK Abstract We propose a framework to extend Markov random walks (Szummer and Jaakkola, 2001 distinct ex- amples are geodesic distances (Tenenbaum, 1998) and Markov random walks (Szummer & Jaakkola
Limit Theorems for the Fibonacci Quantum Walk
Clement Ampadu
2011-08-25
We study the discrete-time quantum walk in one-dimension governed by the Fibonacci transformation .We show localization does not occur for the Fibonacci quantum walk by investigating the stationary distribution of the walk, in addition, we obtain the weak limit theorem.
Limit Theorems for the Fibonacci Quantum Walk
Ampadu, Clement
2011-01-01
We study the discrete-time quantum walk in one-dimension governed by the Fibonacci transformation .We show localization does not occur for the Fibonacci quantum walk by investigating the stationary distribution of the walk, in addition, we obtain the weak limit theorem.
Developmental Continuity? Crawling, Cruising, and Walking
ERIC Educational Resources Information Center
Adolph, Karen E.; Berger, Sarah E.; Leo, Andrew J.
2011-01-01
This research examined developmental continuity between "cruising" (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior…
Diss. ETH No 13748 WALKING GAIT CONTROL
Still, Susanna
Diss. ETH No 13748 WALKING GAIT CONTROL FOR FOUR-LEGGED ROBOTS Bio-inspired technology analyzed for the inter-leg coordination of four-legged walking machines. The controller is implemented using Very Large Scale Integrated (VLSI) technology. It is able to generate walking behaviors for a four-legged machine
Walking cavity solitons Dmitry V. Skryabin1
Skryabin, Dmitry
Walking cavity solitons Dmitry V. Skryabin1 and Alan R. Champneys2 1 Department of Physics manuscript received 20 February 2001; published 24 May 2001 A family of walking solitons is obtained dissipative multicomponent models with walk off. DOI: 10.1103/PhysRevE.63.066610 PACS number s : 42.65.Tg, 42
THE GEORGE WASHINGTON UNIVERSITY WALKING TOUR
Vertes, Akos
THE GEORGE WASHINGTON UNIVERSITY FOGGY BOTTOM CAMPUS WALKING TOUR #12;ACADEMIC CENTER The tour tours.) Turn left and begin walking down H Street. Next to Gelman is Kogan Plaza, our mid-campus quad. Information on our Mount Vernon Campus walking tour is available at the Visitor Center and on our web site
RESEARCH ARTICLE Water-walking devices
Bush, John W.M.
RESEARCH ARTICLE Water-walking devices David L. Hu Æ Manu Prakash Æ Brian Chan Æ John W. M. Bush report recent efforts in the design and construction of water-walking machines inspired by insects: walking on water. Nearly three centuries ago, the biologist Ray (1710) reported with amazement the ability
Generalized open quantum walks on Apollonian networks
?. Pawela; P. Gawron; J. A. Miszczak; P. Sadowski
2015-03-24
We introduce the model of generalized open quantum walks on networks using the Transition Operation Matrices formalism. We focus our analysis on the mean first passage time and the average return time in Apollonian networks. These results differ significantly from a classical walk on these networks. We show a comparison of the classical and quantum behaviour of walks on these networks.
Humanoid robot walking control on inclined planes
Utku Seven; Tunc Akbas; Kaan Can Fidan; Metin Yilmaz; Kemalettin Erbatur
2011-01-01
The humanoid bipedal structure is suitable for a assitive robot functioning in the human environment. However, the bipedal walk is a difficult control problem. Walking just on even floor is not satisfactory for the applicability of a humanoid robot. This paper presents a study on bipedal walk on inclined planes. A Zero Moment Point (ZMP) based reference generation technique is
Decoherence in quantum walks on the hypercube
Alagic, Gorjan; Russell, Alexander
2005-12-15
We study a natural notion of decoherence on quantum random walks over the hypercube. We prove that this model possesses a decoherence threshold beneath which the essential properties of the hypercubic quantum walk, such as linear mixing times, are preserved. Beyond the threshold, we prove that the walks behave like their classical counterparts.
Decoherence in Quantum Walks on the Hypercube
Gorjan Alagic; Alexander Russell
2006-02-03
We study a natural notion of decoherence on quantum random walks over the hypercube. We prove that in this model there is a decoherence threshold beneath which the essential properties of the hypercubic quantum walk, such as linear mixing times, are preserved. Beyond the threshold, we prove that the walks behave like their classical counterparts.
RANDOM WALK IN DETERMINISTICALLY CHANGING ENVIRONMENT
Liverani, Carlangelo
RANDOM WALK IN DETERMINISTICALLY CHANGING ENVIRONMENT DMITRY DOLGOPYAT AND CARLANGELO LIVERANI Abstract. We consider a random walk with transition probabilities weakly dependent on an environment of the environment the walk satisfies the CLT. 1. Introduction The continuing interest in the limit properties
Billie Giles-Corti
2001-01-01
Walking was firmly put on the public health agenda in 1996 following publication of the US Surgeon General's Report on Physical Activity. This report coincided with growing international concern about the burden of obesity, which in developed countries, is contributed to by increasingly inactive lifestyles. After reviewing decades of epidemiologic al evidence, the US Surgeon General concluded that physical inactivity
Efficient Robotic Walking by Learning
Dudek, Gregory
for all the encouragement they have given. Finally, I want to thank my mom, my dad, my granny, my brother and then adapt its gait accordingly. Identifying the terrain in real-time helps the robot plan its gait on that terrain and effectively increase the walking efficiency in real-time. We use a cost-based unsupervised
Listening Walks and Singing Maps
ERIC Educational Resources Information Center
Cardany, Audrey Berger
2011-01-01
The Listening Walk by Paul Showers and illustrated by Aliki, and "It's My City: A Singing Map" by April Pulley Sayre with pictures by Denis Roche, provide two examples of texts that aid in building children's phonological awareness for reading and music. The author describes each narrative and discusses its function as a springboard to composition…
Successful Statewide Walking Program Websites
ERIC Educational Resources Information Center
Teran, Bianca Maria; Hongu, Nobuko
2012-01-01
Statewide Extension walking programs are making an effort to increase physical activity levels in America. An investigation of all 20 of these programs revealed that 14 use websites as marketing and educational tools, which could prove useful as the popularity of Internet communities continues to grow. Website usability information and an analysis…
WW Scattering in Walking Technicolor
Roshan Foadi; Francesco Sannino
2008-01-04
We analyze the WW scattering in scenarios of dynamical electroweak symmetry breaking of walking technicolor type. We show that in these theories there are regions of the parameters space allowed by the electroweak precision data, in which unitarity violation is delayed at tree level up to around 3-4 TeV without the inclusion of any sub-TeV resonances.
Monkeys and Walks Muhammad Waliji
May, J. Peter
Monkeys and Walks Muhammad Waliji August 12, 2006 1 Preliminaries We will be dealing with outcomes is independent. 2 The Infinite-Monkey Theorem Before we state the infinite-monkey theorem, we will prove a useful speaking, the infinite-monkey theorem states that if a monkey hits keys on a typewriter at random
ERIC Educational Resources Information Center
Weir, Phil
1994-01-01
During a walk, an outdoor education teacher reflects on the status of outdoor education in Ottawa (Canada) and importance of maintaining a close relationship with nature. He looks for signs of an old log home site, observes a hawk's flight, discovers remains of a plastic bag in an owl pellet, and realizes that everyone is working on survival. (LP)
Clairvoyant scheduling of random walks
Gacs, Peter
Â´acs (BU) Clairvoyant demon April 25, 2008 1 / 65 #12;Introduction The clairvoyant demon problem 0 1 2 3 4 nodes. In each instant, either X or Y will move. A demon knows both (infinite) walks completely . . ., Y = 0012111443 . . .. The repetitions are the demon's insertions. PÂ´eter GÂ´acs (BU) Clairvoyant
Everyday Fitness Ideas from the National Institute on Aging at NIH www.nia.nih.gov/Go4Life Walking Safely in ... For more information, see the Go4Life tip sheet Fitness Clothes and Shoes . www.nia.nih.gov/Go4Life ...
Bush, John W.M.
Water-Walking Submitted by David L. Hu, Brian Chan, and John W. M. Bush, Massachusetts Institute of Technology The water strider Fig. 1 is an insect of characteristic length 1 cm and weight 10 dynes of hairs that render its legs effectively nonwetting.1 The water strider propels itself by driving its
Walk Through a Hydroelectric Project
NSDL National Science Digital Library
This site offers a virtual walk-through tour of a hydroelectric facility. The creation of hydroelectricity begins at the dam, where the power plant converts the force of falling water into electricity. It shows how dams operate and the equipment necessary for electrical generation.
University of Sussex boundary walk
Sussex, University of
the Biology Field Trials Plot; this is an open air laboratory where ecological research is done for the School right and you will find yourself back at the beginning of the walk. Read more about wildlife on campus at www.sussex.ac.uk/walkonthewildside Wildlife photography by Paul Cecil Way marker posts mark the route
Kim, Duck O.
or indoors at the University of Connecticut Health Center, you will see art...paintings, sculptures, mobilesHealing Pathways A Walking Tour of the UConn Health Center Public Art Collection Made possible. The architecture of the main building is itself a work of art with curving lines, inner courtyards, soaring
Behavior Management by Walking Around
ERIC Educational Resources Information Center
Boardman, Randolph M.
2004-01-01
An emerging concept from the field of business is to manage organizations by wandering around and engaging staff and consumers in informal interactions. The author extends these ideas to settings serving children and youth. In the best seller, In Search of Excellence, Peters and Waterman (1982) introduced Management by Walking Around (MBWA) as an…
Beam Walking in Special Education
ERIC Educational Resources Information Center
Broadhead, Geoffrey D.
1974-01-01
An experimental test on beam walking (for balance), administered to 189 minimally brain injured and 226 educable mentally retarded (EMR) 8- to 13-year-old children, yielded results such as reliability estimates for the mean of three trials were high and there was greater performance reliability for EMR children. (MC)
Walk around the Block Curriculum.
ERIC Educational Resources Information Center
Center for Understanding the Built Environment, Prairie Village, KS.
This curriculum packet contains two teacher-developed lesson plans for upper elementary students focusing on the built environment. The first lesson plan, "The Built Environment--An Integrating Theme" (Liesa Schroeder), offers suggestions for developing a walking tour around the school neighborhood, a historic area, or a city square. It finds that…
Borwein, Jonathan
Introduction Randomness Normality Random walks Features of random walks Other tools & representations Media coverage Seeing Things by Walking on Real Numbers Jonathan Borwein FRSC FAAS FAA FBAS (Joint Revised 10-04-2014 Borwein and AragÂ´on (University of Newcastle, Australia) Walking on real numbers www.carma.newcastle.edu.au/walks
Periodicity for the Hadamard walk on cycles
Norio Konno; Yuki Shimizu; Masato Takei
2015-04-24
The present paper treats the period T_N of the Hadamard walk on a cycle C_N with N vertices. Dukes (2014) considered the periodicity of more general quantum walks on C_N and showed T_2 =2, T_4=8, T_8=24 for the Hadamard walk case. We prove that the Hadamard walk does not have any period except for his case, i.e., N=2, 4, 8. Our method is based on a path counting and cyclotomic polynomials which is different from his approach based on the property of eigenvalues for unitary matrix that determines the evolution of the walk.
Einstein's random walk and thermal diffusion
Yong-Jung Kim
2013-07-17
Thermal diffusion has been studied for over 150 years. Despite of the long history and the increasing importance of the phenomenon, the physics of thermal diffusion remains poorly understood. In this paper Ludwig's thermal diffusion is explained using Einstein's random walk. The only new structure added is the spatial heterogeneity of the random walk to reflect the temperature gradient of thermal diffusion. Hence, the walk length and the walk speed are location dependent functions in this paper. Then, a mathematical understanding of such a random walk gives the foundation of the thermal diffusion as clearly as the original homogeneous case of Einstein.
Biased random walks on multiplex networks
Battiston, Federico; Latora, Vito
2015-01-01
Biased random walks on complex networks are a particular type of walks whose motion is biased on properties of the destination node, such as its degree. In recent years they have been exploited to design efficient strategies to explore a network, for instance by constructing maximally mixing trajectories or by sampling homogeneously the nodes. In multiplex networks, the nodes are related through different types of links (layers or communication channels), and the presence of connections at different layers multiplies the number of possible paths in the graph. In this work we introduce biased random walks on multiplex networks and provide analytical solutions for their long-term properties such as the stationary distribution and the entropy rate. We focus on degree-biased walks and distinguish between two subclasses of random walks: extensive biased walks consider the properties of each node separately at each layer, intensive biased walks deal instead with intrinsically multiplex variables. We study the effec...
To Walk or Not to Walk?: The Hierarchy of Walking Needs
ERIC Educational Resources Information Center
Alfonzo, Mariela
2005-01-01
The multitude of quality of life problems associated with declining walking rates has impelled researchers from various disciplines to identify factors related to this behavior change. Currently, this body of research is in need of a transdisciplinary, multilevel theoretical model that can help explain how individual, group, regional, and…
Quantum walks with infinite hitting times
Krovi, Hari; Brun, Todd A. [Communication Sciences Institute, University of Southern California, Los Angeles, California 90089 (United States)
2006-10-15
Hitting times are the average time it takes a walk to reach a given final vertex from a given starting vertex. The hitting time for a classical random walk on a connected graph will always be finite. We show that, by contrast, quantum walks can have infinite hitting times for some initial states. We seek criteria to determine if a given walk on a graph will have infinite hitting times, and find a sufficient condition, which for discrete time quantum walks is that the degeneracy of the evolution operator be greater than the degree of the graph. The set of initial states which give an infinite hitting time form a subspace. The phenomenon of infinite hitting times is in general a consequence of the symmetry of the graph and its automorphism group. Using the irreducible representations of the automorphism group, we derive conditions such that quantum walks defined on this graph must have infinite hitting times for some initial states. In the case of the discrete walk, if this condition is satisfied the walk will have infinite hitting times for any choice of a coin operator, and we give a class of graphs with infinite hitting times for any choice of coin. Hitting times are not very well defined for continuous time quantum walks, but we show that the idea of infinite hitting-time walks naturally extends to the continuous time case as well.
Continuous Limit of Discrete Quantum Walks
Dheeraj M N; Todd A. Brun
2015-01-27
Quantum walks can be defined in two quite distinct ways: discrete-time and continuous-time quantum walks (DTQWs and CTQWs). For classical random walks, there is a natural sense in which continuous-time walks are a limit of discrete-time walks. Quantum mechanically, in the discrete-time case, an additional "coin space" must be appended for the walk to have nontrivial time evolution. Continuous-time quantum walks, however, have no such constraints. This means that there is no completely straightforward way to treat a CTQW as a limit of DTQW, as can be done in the classical case. Various approaches to this problem have been taken in the past. We give a construction for walks on $d$-regular, $d$-colorable graphs when the coin flip operator is Hermitian: from a standard DTQW we construct a family of discrete-time walks with a well-defined continuous-time limit on a related graph. One can think of this limit as a {\\it coined} continuous-time walk. We show that these CTQWs share some properties with coined DTQWs. In particular, we look at spatial search by a DTQW over the 2-D torus (a grid with periodic boundary conditions) of size $\\sqrt{N}\\times\\sqrt{N}$, where it was shown \
Positive messaging promotes walking in older adults.
Notthoff, Nanna; Carstensen, Laura L
2014-06-01
Walking is among the most cost-effective and accessible means of exercise. Mounting evidence suggests that walking may help to maintain physical and cognitive independence in old age by preventing a variety of health problems. However, older Americans fall far short of meeting the daily recommendations for walking. In 2 studies, we examined whether considering older adults' preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, we compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, we examined within-person change in walking in older adults in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages, and the effect was sustained across the intervention period. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles. Future research is needed to examine the mechanisms underlying the greater effectiveness of positively- as opposed to negatively-framed messages and the generalizability of findings to other intervention targets and other subpopulations of older adults. PMID:24956001
Quantum walks with infinite hitting times
Hari Krovi; Todd A. Brun
2006-06-10
Hitting times are the average time it takes a walk to reach a given final vertex from a given starting vertex. The hitting time for a classical random walk on a connected graph will always be finite. We show that, by contrast, quantum walks can have infinite hitting times for some initial states. We seek criteria to determine if a given walk on a graph will have infinite hitting times, and find a sufficient condition, which for discrete time quantum walks is that the degeneracy of the evolution operator be greater than the degree of the graph. The set of initial states which give an infinite hitting time form a subspace. The phenomenon of infinite hitting times is in general a consequence of the symmetry of the graph and its automorphism group. Using the irreducible representations of the automorphism group, we derive conditions such that quantum walks defined on this graph must have infinite hitting times for some initial states. In the case of the discrete walk, if this condition is satisfied the walk will have infinite hitting times for any choice of a coin operator, and we give a class of graphs with infinite hitting times for any choice of coin. Hitting times are not very well-defined for continuous time quantum walks, but we show that the idea of infinite hitting-time walks naturally extends to the continuous time case as well.
Walking dynamics are symmetric (enough).
Ankaral?, M Mert; Sefati, Shahin; Madhav, Manu S; Long, Andrew; Bastian, Amy J; Cowan, Noah J
2015-07-01
Many biological phenomena such as locomotion, circadian cycles and breathing are rhythmic in nature and can be modelled as rhythmic dynamical systems. Dynamical systems modelling often involves neglecting certain characteristics of a physical system as a modelling convenience. For example, human locomotion is frequently treated as symmetric about the sagittal plane. In this work, we test this assumption by examining human walking dynamics around the steady state (limit-cycle). Here, we adapt statistical cross-validation in order to examine whether there are statistically significant asymmetries and, even if so, test the consequences of assuming bilateral symmetry anyway. Indeed, we identify significant asymmetries in the dynamics of human walking, but nevertheless show that ignoring these asymmetries results in a more consistent and predictive model. In general, neglecting evident characteristics of a system can be more than a modelling convenience--it can produce a better model. PMID:26236826
Quantum walks with random phase shifts
Kosik, Jozef [Research Center for Quantum Information, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Quniverse, Liscie udolie 116, 841 04 Bratislava (Slovakia); Buzek, Vladimir [Research Center for Quantum Information, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Abteilung fuer Quantenphysik, Universitaet Ulm, 89069 Ulm (Germany); Hillery, Mark [Department of Physics, Hunter College of CUNY, 695 Park Avenue, New York, New York 10021 (United States)
2006-08-15
We investigate quantum walks in multiple dimensions with different quantum coins. We augment the model by assuming that at each step the amplitudes of the coin state are multiplied by random phases. This model enables us to study in detail the role of decoherence in quantum walks and to investigate the quantum-to-classical transition. We also provide classical analog of the quantum random walks studied. Interestingly enough, it turns out that the classical counterparts of some quantum random walks are classical random walks with a memory and biased coin. In addition random phase shifts 'simplify' the dynamics (the cross-interference terms of different paths vanish on average) and enable us to give a compact formula for the dispersion of such walks.
Quantum walks driven by many coins
Brun, Todd A.; Ambainis, Andris [Institute for Advanced Study, Einstein Drive, Princeton, New Jersey 08540 (United States); Carteret, Hilary A. [Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)
2003-05-01
Quantum random walks have been much studied recently, largely due to their highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum random walk on the line: the use of multiple quantum 'coins' (or more generally, coins of higher dimension) in order to diminish the effects of interference between paths. We find solutions to this system in terms of the single-coin random walk, and compare the asymptotic limit of these solutions to numerical simulations. We find exact analytical expressions for the time dependence of the first two moments, and show that in the long-time limit the ''quantum-mechanical'' behavior of the one-coin walk persists, even if each coin is flipped only twice. We further show that this is generic for a very broad class of possible walks, and that this behavior disappears only in the limit of a new coin for every step of the walk.
Braiding Interactions in Anyonic Quantum Walks
Lauri J. Lehman; Vaclav Zatloukal; Jiannis K. Pachos; Gavin K. Brennen
2012-10-12
The anyonic quantum walk is a dynamical model describing a single anyon propagating along a chain of stationary anyons and interacting via mutual braiding statistics. We review the recent results on the effects of braiding statistics in anyonic quantum walks in quasi-one dimensional ladder geometries. For anyons which correspond to spin-1/2 irreps of the quantum groups $SU(2)_k$, the non-Abelian species $(1
Joh, Kenneth; Chakrabarti, Sandip; Boarnet, Marlon G.; Woo, Ayoung
2015-07-10
Promoting walking travel is considered important for reducing automobile use and improving public health. Recent U.S. transportation policy has incentivized investments in alternative, more sustainable transportation modes such as walking, bicycling...
Continuous limit of discrete quantum walks
NASA Astrophysics Data System (ADS)
M N, Dheeraj; Brun, Todd A.
2015-06-01
Quantum walks can be defined in two quite distinct ways: discrete-time and continuous-time quantum walks (DTQWs and CTQWs). For classical random walks, there is a natural sense in which continuous-time walks are a limit of discrete-time walks. Quantum mechanically, in the discrete-time case, an additional "coin space" must be appended for the walk to have nontrivial time evolution. Continuous-time quantum walks, however, have no such constraints. This means that there is no completely straightforward way to treat a CTQW as a limit of a DTQW, as can be done in the classical case. Various approaches to this problem have been taken in the past. We give a construction for walks on d -regular, d -colorable graphs when the coin flip operator is Hermitian: from a standard DTQW we construct a family of discrete-time walks with a well-defined continuous-time limit on a related graph. One can think of this limit as a "coined" continuous-time walk. We show that these CTQWs share some properties with coined DTQWs. In particular, we look at a spatial search by a DTQW over the two-dimensional (2D) torus (a grid with periodic boundary conditions) of size ?{N }×?{N } , where it was shown that a coined DTQW can search in time O (?{N }logN ) , but a standard CTQW takes ? (N ) time to search for a marked element. The continuous limit of the DTQW search over the 2D torus exhibits the O (?{N }logN ) scaling, like the coined walk it is derived from. We also look at the effects of graph symmetry on the limiting walk, and show that the properties are similar to those of the DTQW as shown in Krovi and Brun, Phys. Rev. A 75, 062332 (2007), 10.1103/PhysRevA.75.062332.
Walking Wave as a Model of Particle
A. V. Goryunov
2012-05-02
The concept of walking wave is introduced from classical relativistic positions. One- and three-dimensional walking waves considered with their wave equations and dispersion equations. It is shown that wave characteristics (de Broglie's and Compton's wavelengths) and corpuscular characteristics (energy-momentum vector and the rest mass) of particle may be expressed through parameters of walking wave. By that the new view on a number concepts of physic related with wave-particle duality is suggested.
Walking gauge dynamics and realistic technicolor
Sundrum, R. Department of Physics, University of California, Berkeley 94720 )
1992-02-05
A realistic technicolor model, effective below 150 TeV is outlined. The new feature of the model is that the third generation quarks are unified with the technifermions into multiplets of a walking gauge force down to a scale of [similar to]10 TeV. Because they directly feel the walking force these quarks can have mass enhancements even greater than those of conventional walking schemes. Electroweak radiative corrections are estimable and within experimental limits.
Machines that walk: The adaptive suspension vehicle
Shin-Min Song; Kenneth J. Waldron
1989-01-01
The design and operation of statically stable fully terrain-adaptive walking machines are discussed, with an emphasis on the adaptive-suspension vehicle developed at Ohio State University (Waldron and McGhee, 1986). Chapters are devoted to a review of walking-machine development, gait analysis and gaits for level walking, gaits for irregular terrain, coordination, leg design by four-bar linkage synthesis, design of a pantograph
Controlling quantum walks with coin eigenstates
Martin Stefanak; Igor Jex
2014-05-29
The control of quantum walk is made particularly transparent when the initial state is expressed in terms of the eigenstates of the coin operator. We show that the group-velocity density acquires a much simpler form when expressed in this basis. This allows us to obtain a much deeper understanding of the role of the initial coin state on the dynamics of quantum walks and control it. We find that the eigenvectors of the coin result in an extremal regime of a quantum walk. The approach is illustrated on two examples of quantum walks on a line.
Random walks between leaves of random networks
NASA Astrophysics Data System (ADS)
Lancaster, David
2014-02-01
Motivated by the desire to model internet traffic we consider random walks that start and are absorbed on the leaves of random networks and study the length of such walks. We present and test two techniques to analyse these walks. On Erd?s-Rényi random graphs where the probability of a walk decays exponentially with its length, the methods give indistinguishable results for the decay exponent. This simple form of decay is not apparent on heterogeneous networks such as Barabási-Albert scale free networks and in this case each technique is demonstrated to have a different strength.
Efficient quantum circuit implementation of quantum walks
Douglas, B. L.; Wang, J. B.
2009-05-15
Quantum walks, being the quantum analog of classical random walks, are expected to provide a fruitful source of quantum algorithms. A few such algorithms have already been developed, including the 'glued trees' algorithm, which provides an exponential speedup over classical methods, relative to a particular quantum oracle. Here, we discuss the possibility of a quantum walk algorithm yielding such an exponential speedup over possible classical algorithms, without the use of an oracle. We provide examples of some highly symmetric graphs on which efficient quantum circuits implementing quantum walks can be constructed and discuss potential applications to quantum search for marked vertices along these graphs.
Cell phones change the way we walk.
Lamberg, Eric M; Muratori, Lisa M
2012-04-01
Cell phone use among pedestrians leads to increased cognitive distraction, reduced situation awareness and increases in unsafe behavior. Performing a dual-task, such as talking or texting with a cell phone while walking, may interfere with working memory and result in walking errors. At baseline, thirty-three participants visually located a target 8m ahead; then vision was occluded and they were instructed to walk to the remembered target. One week later participants were assigned to either walk, walk while talking on a cell phone, or walk while texting on a cell phone toward the target with vision occluded. Duration and final location of the heel were noted. Linear distance traveled, lateral angular deviation from the start line, and gait velocity were derived. Changes from baseline to testing were analyzed with paired t-tests. Participants engaged in cell phone use presented with significant reductions in gait velocity (texting: 33% reduction, p=0.01; talking: 16% reduction, p=0.02). Moreover, participants who were texting while walking demonstrated a 61% increase in lateral deviation (p=0.04) and 13% increase in linear distance traveled (p=0.03). These results suggest that the dual-task of walking while using a cell phone impacts executive function and working memory and influences gait to such a degree that it may compromise safety. Importantly, comparison of the two cell phone conditions demonstrates texting creates a significantly greater interference effect on walking than talking on a cell phone. PMID:22226937
IMU-based ambulatory walking speed estimation in constrained treadmill and overground walking.
Yang, Shuozhi; Li, Qingguo
2012-01-01
This study evaluated the performance of a walking speed estimation system based on using an inertial measurement unit (IMU), a combination of accelerometers and gyroscopes. The walking speed estimation algorithm segments the walking sequence into individual stride cycles (two steps) based on the inverted pendulum-like behaviour of the stance leg during walking and it integrates the angular velocity and linear accelerations of the shank to determine the displacement of each stride. The evaluation was performed in both treadmill and overground walking experiments with various constraints on walking speed, step length and step frequency to provide a relatively comprehensive assessment of the system. Promising results were obtained in providing accurate and consistent walking speed/step length estimation in different walking conditions. An overall percentage root mean squared error (%RMSE) of 4.2 and 4.0% was achieved in treadmill and overground walking experiments, respectively. With an increasing interest in understanding human walking biomechanics, the IMU-based ambulatory system could provide a useful walking speed/step length measurement/control tool for constrained walking studies. PMID:21294007
On the Levy-walk Nature of Human Mobility: Do Humans Walk like Monkeys?
Young, R. Michael
On the Levy-walk Nature of Human Mobility: Do Humans Walk like Monkeys? Injong Rhee, Minsu Shin under existing mobility models. I. INTRODUCTION Do humans walk like monkeys? It is not about upright mobility have similar statistical patterns as monkeys? This paper pro- vides statistical evidence
Walk-Startup of a Two-Legged Walking Mechanism
NASA Astrophysics Data System (ADS)
Babkovi?, Kalman; Nagy, László; Krklješ, Damir; Borovac, Branislav
There is a growing interest towards humanoid robots. One of their most important characteristic is the two-legged motion - walk. Starting and stopping of humanoid robots introduce substantial delays. In this paper, the goal is to explore the possibility of using a short unbalanced state of the biped robot to quickly gain speed and achieve the steady state velocity during a period shorter than half of the single support phase. The proposed method is verified by simulation. Maintainig a steady state, balanced gait is not considered in this paper.
The 'passive dynamic walking machine' used in the experiments.
Collins, Steven H.
requires little muscular effort, yet it makes walking much easier. "This puts to rest the theory that arm July 2009 Cosmos Online #12;Related articles Maths proves the silliness of 'silly walks' Walking tall
ORIGINAL ARTICLE Relationship Between Step Length Asymmetry and Walking
ORIGINAL ARTICLE Relationship Between Step Length Asymmetry and Walking Performance in Subjects step length asymmetry and walking performance in subjects with chronic hemiparesis. Arch Phys Med and hemiparetic walking performance. Design: Descriptive. Setting: Gait analysis laboratory. Participants
Franceschini, Marco; Rampello, Anais; Agosti, Maurizio; Massucci, Maurizio; Bovolenta, Federica; Sale, Patrizio
2013-01-01
Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW), in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS). One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance. PMID:23468871
Quantum Walks with Encrypted Data
NASA Astrophysics Data System (ADS)
Rohde, Peter P.; Fitzsimons, Joseph F.; Gilchrist, Alexei
2012-10-01
In the setting of networked computation, data security can be a significant concern. Here we consider the problem of allowing a server to remotely manipulate client supplied data, in such a way that both the information obtained by the client about the server’s operation and the information obtained by the server about the client’s data are significantly limited. We present a protocol for achieving such functionality in two closely related models of restricted quantum computation—the boson sampling and quantum walk models. Because of the limited technological requirements of the boson scattering model, small scale implementations of this technique are feasible with present-day technology.
Science Sampler: Walk this way
NSDL National Science Digital Library
Jan Fechheim
2007-02-01
While they themselves may be in constant motion, getting middle school students to really understand the motion shown in distance/time graphs can often be a challenge--but a challenge that must be taken on! In virtually every listing of national and state science standards for middle school students, the concept of graphically representing motion is included. In the lesson described here, students try to walk along a line marked with distance measurements so that their movement mirrors a given distance/time graph. Depending on the length of the class period, the lesson can be completed in one or two days.
Visual Acuity During Treadmill Walking
NASA Technical Reports Server (NTRS)
Peters, B. T.; Brady, R.; vanEmmerik, R. E. A.; Bloomberg, Jacob J.
2006-01-01
An awareness of the physical world is essential for successful navigation through the environment. Vision is the means by which this awareness is made possible for most people. However, without adequate compensation, the movements of the body during walking could impair vision. Previous research has shown how the eyes, head and trunk movements are coordinated to provide the compensation necessary for clear vision, but the overall effectiveness of these coordinated movements is unknown. The goal of the research presented here was to provide a direct measure of visual performance during locomotion, while also investigating the degree to which coordinated head and body movements can be altered to facilitate the goal of seeing clearly.
Quantum walks with encrypted data.
Rohde, Peter P; Fitzsimons, Joseph F; Gilchrist, Alexei
2012-10-12
In the setting of networked computation, data security can be a significant concern. Here we consider the problem of allowing a server to remotely manipulate client supplied data, in such a way that both the information obtained by the client about the server's operation and the information obtained by the server about the client's data are significantly limited. We present a protocol for achieving such functionality in two closely related models of restricted quantum computation-the boson sampling and quantum walk models. Because of the limited technological requirements of the boson scattering model, small scale implementations of this technique are feasible with present-day technology. PMID:23102287
Universal computation by quantum walk
Andrew M. Childs
2008-06-12
In some of the earliest work on quantum mechanical computers, Feynman showed how to implement universal quantum computation by the dynamics of a time-independent Hamiltonian. I show that this remains possible even if the Hamiltonian is restricted to be a sparse matrix with all entries equal to 0 or 1, i.e., the adjacency matrix of a low-degree graph. Thus quantum walk can be regarded as a universal computational primitive, with any desired quantum computation encoded entirely in some underlying graph. The main idea of the construction is to implement quantum gates by scattering processes.
ERIC Educational Resources Information Center
Granada, Janet; Vriesenga, Michael
2008-01-01
Walk-through classroom observations are an effective way for principals to learn about and shape instruction and culture in their schools. But many principals don't use walk-throughs to their potential because of the time it takes to store, process, analyze, and give feedback. To facilitate the use of this valuable observation tool, the Kentucky…
Random Walks on Graphs: A Survey
L. LOV
1996-01-01
Various aspects of the theory of random walks on graphs are surveyed. In particular, estimates on the important parameters of access time, commute time, cover time and mixing time are discussed. Connections with the eigenvalues of graphs and with electrical networks, and the use of these connections in the study of random walks is described. We also sketch recent algorithmic
Walks: An Effective Approach to Learning.
ERIC Educational Resources Information Center
Wineberg, Lenore Peachin
1997-01-01
Whether planned or spontaneous, walks offer young children unexpected pleasures and discoveries about their environment. This article describes five strategies for using walks in early childhood programs (plan, gather information, develop safety rules, integrate with the curriculum, assess what has been learned), as well as specific indoor,…
TALKING WITHOUT WALKING: CANADA'S INEFFECTIVE CLIMATE EFFORT
TALKING WITHOUT WALKING: CANADA'S INEFFECTIVE CLIMATE EFFORT Nic Rivers and Mark Jaccard Walking: Canada's Ineffective Climate Effort nic rivers and mark jaccard Since the late 1980s, Canada has) in order to reduce the risk of human-induced climate change. In these processes it has made several
Excited Random Walk in One Dimension
NASA Astrophysics Data System (ADS)
Antal, Tibor
2005-03-01
We study the k-excited random walk, in which each site initially contains k cookies, and a random walk that is at a site that contains at least one cookie eats a cookie and then hops to the right with probability p and to the left with probability q=1-p. If the walk hops from an empty site, there is no bias. For the 1-excited walk on the half-line (each site initially contains one cookie), the probability of first returning to the starting point at time t scales as t-1-q. We also derive the probability distribution of the position of the leftmost uneaten cookie in the large time limit. For the infinite line, the probability distribution of the position of the 1-excited walk has an unusual anomaly at the origin and the distributions of positions for the leftmost and rightmost uneaten cookie develop a power-law singularity at the origin. The 2-excited walk on the infinite line exhibits peculiar features in the regime p>3/4, where the walk is transient, including a mean displacement that grows as t^?, with ?>12 dependent on p, and a breakdown of scaling for the probability distribution of the walk.
The excited random walk in one dimension
NASA Astrophysics Data System (ADS)
Antal, T.; Redner, S.
2005-03-01
We study the excited random walk, in which a walk that is at a site that contains cookies eats one cookie and then hops to the right with probability p and to the left with probability q = 1 - p. If the walk hops onto an empty site, there is no bias. For the 1-excited walk on the half-line (one cookie initially at each site), the probability of first returning to the starting point at time t scales as t-(2-p). Although the average return time to the origin is infinite for all p, the walk eats, on average, only a finite number of cookies until this first return when p < 1/2. For the infinite line, the probability distribution for the 1-excited walk has an unusual anomaly at the origin. The positions of the leftmost and rightmost uneaten cookies can be accurately estimated by probabilistic arguments and their corresponding distributions have power-law singularities. The 2-excited walk on the infinite line exhibits peculiar features in the regime p > 3/4, where the walk is transient, including a mean displacement that grows as t?, with \
Effect of encouragement on walking test performance
G H Guyatt; S O Pugsley; M J Sullivan; P J Thompson; L Berman; N L Jones; E L Fallen; D W Taylor
1984-01-01
Walking tests, frequently used to document effects of treatment on exercise capacity, have never been standardised. We studied the effects of encouragement on walking test performance in a randomised study that controlled for the nature of the underlying disease, time of day, and order effects. We randomised 43 patients with chronic airflow limitation or chronic heart failure or both to
Realistic Human Walking Paths David C. Brogan
Brogan, David
Realistic Human Walking Paths David C. Brogan Department of Computer Science University of Virginia are influenced by kinematic and dynami- cal constraints. A realistic model of human walking paths is an important model of path planning that extends previous models through its significant use of pedestrian
Power Demand for Walking on the Treadmill
NSDL National Science Digital Library
Gaylord T. Hageseth
2000-02-01
This paper presents a mathematical model for walking on the treadmill that calculates the minimum power required for walking on the level at a constant speed and relates it to the pace length. The calculation includes both the horizontal and vertical moti
Welly-Walks for Science Learning
ERIC Educational Resources Information Center
Fradley, Carol
2006-01-01
This article discusses how a regular walk in the wind or the rain can help develop science knowledge and skills. The author describes one "welly-walk" and links it to National Curriculum for England requirements so that readers can see how easy it is. (Contains 1 figure and 1 box.)
Quantum Random Walks Hit Exponentially Faster
Julia Kempe
2002-01-01
We show that the hitting time of the discrete time quantum random walk on the n-bit hypercube from one corner to its opposite is polynomial in n. This gives the first exponential quantum-classical gap in the hitting time of discrete quantum random walks. We provide the framework for quantum hitting time and give two alternative definitions to set the ground
Interface Reconstruction with Directional Walking
Yao, J
2009-05-22
Young's interface reconstruction with three-dimensional arbitrary mesh, in general, is rather tedious to implement compared to the case of a regular mesh. The main difficulty comes from the construction of a planar facet that bounds a certain volume inside a cell. Unlike the five basic configurations with a Cartesian mesh, there can be a great number of different configurations in the case of a general mesh. We represent a simple method that can derive the topology/geometry of the intersection of arbitrary planar objects in a uniform way. The method is based on a directional walking on the surface of objects, and links the intersection points with the paths of the walking naturally defining the intersection of objects. The method works in both two and three dimensions. The method does not take advantage of convexity, thus decomposition of an object is not necessary. Therefore, the solution with this method will have a reduced number of edges and less data storage, compared with methods that use shape decomposition. The treatment is general for arbitrary polyhedrons, and no look-up tables are needed. The same operation can easily be extended for curved geometry. The implementation of this new algorithm shall allow the interface reconstruction on an arbitrary mesh to be as simple as it is on a regular mesh. Furthermore, we exactly compute the integral of partial cell volume bounded by quadratic interface. Therefore, interface reconstruction with higher than second order accuracy can be achieved on an arbitrary mesh.
Toe walking in autism: further observations.
Accardo, Pasquale J; Barrow, William
2015-04-01
Toe walking has been associated with language disorders and autism. To better understand the association between persistent toe walking and sensory and motor variables in children with autism, the degree of toe walking was compared with an estimate of the severity of sensory integration dysfunction symptoms and the presence of residual components of the tonic labyrinthine in supine reflex pattern in 61 children younger than 37 months of age with newly diagnosed autism. There was no association between the presence of toe walking and sensory symptoms (P = .5298) or language age (P = .6142), but there was an association between toe walking and the presence of components of the tonic labyrinthine reflex (P = .04222). These preliminary results support the contribution of subtle motor deficits to the evolution of some behaviors associated with autism. PMID:24563477
Strongly trapped two-dimensional quantum walks
NASA Astrophysics Data System (ADS)
Kollár, B.; Kiss, T.; Jex, I.
2015-02-01
Discrete time quantum walks (DTQWs) are nontrivial generalizations of random walks with a broad scope of applications. In particular, they can be used as computational primitives, and they are suitable tools for simulating other quantum systems. DTQWs usually spread ballistically due to their quantumness. In some cases, however, they can remain localized at their initial state (trapping). The trapping and other fundamental properties of DTQWs are determined by the choice of the coin operator. We introduce and analyze a type of walks driven by a coin class leading to strong trapping, complementing the known list of walks. This class of walks exhibits a number of exciting properties with possible applications ranging from light pulse trapping in a medium to topological effects and quantum search.
Interventions to Improve Walking in Older Adults
Brach, Jennifer S.; VanSwearingen, Jessie M.
2013-01-01
Interventions to improve walking in older adults have historically been multifactorial (i.e. strengthening, endurance and flexibility programs) focusing on improving the underlying impairments. These impairment-based programs have resulted in only modest improvements in walking. In older adults, walking is slow, less stable, inefficient, and the timing and coordination of stepping with postures and phases of gait is poor. We argue the timing and coordination problems are evidence of the loss of motor skill in walking. Taking a lesson from the sports world and from neurorehabilitation, task-oriented motor learning exercise is an essential component of training to improve motor skill and may be a beneficial approach to improving walking in older adults. In this article we: 1) briefly review the current literature regarding impairment-based interventions for improving mobility, 2) discuss why the results have been only modest, and 3) suggest an alternative approach to intervention (i.e. task oriented motor learning). PMID:24319641
One dimensional quantum walk with unitary noise
Daniel Shapira; Ofer Biham; A. J. Bracken; Michelle Hackett
2003-09-07
The effect of unitary noise on the discrete one-dimensional quantum walk is studied using computer simulations. For the noiseless quantum walk, starting at the origin (n=0) at time t=0, the position distribution Pt(n) at time t is very different from the Gaussian distribution obtained for the classical random walk. Furthermore, its standard deviation, sigma(t) scales as sigma(t) ~ t, unlike the classical random walk for which sigma(t) ~ sqrt{t}. It is shown that when the quantum walk is exposed to unitary noise, it exhibits a crossover from quantum behavior for short times to classical-like behavior for long times. The crossover time is found to be T ~ alpha^(-2) where alpha is the standard deviation of the noise.
Hitting time for the continuous quantum walk
Martin Varbanov; Hari Krovi; Todd A. Brun
2008-03-24
We define the hitting (or absorbing) time for the case of continuous quantum walks by measuring the walk at random times, according to a Poisson process with measurement rate $\\lambda$. From this definition we derive an explicit formula for the hitting time, and explore its dependence on the measurement rate. As the measurement rate goes to either 0 or infinity the hitting time diverges; the first divergence reflects the weakness of the measurement, while the second limit results from the Quantum Zeno effect. Continuous-time quantum walks, like discrete-time quantum walks but unlike classical random walks, can have infinite hitting times. We present several conditions for existence of infinite hitting times, and discuss the connection between infinite hitting times and graph symmetry.
Hitting Time of Quantum Walks with Perturbation
Chen-Fu Chiang; Guillermo Gomez
2011-07-14
The hitting time is the required minimum time for a Markov chain-based walk (classical or quantum) to reach a target state in the state space. We investigate the effect of the perturbation on the hitting time of a quantum walk. We obtain an upper bound for the perturbed quantum walk hitting time by applying Szegedy's work and the perturbation bounds with Weyl's perturbation theorem on classical matrix. Based on the definition of quantum hitting time given in MNRS algorithm, we further compute the delayed perturbed hitting time (DPHT) and delayed perturbed quantum hitting time (DPQHT). We show that the upper bound for DPQHT is actually greater than the difference between the square root of the upper bound for a perturbed random walk and the square root of the lower bound for a random walk.
Walking Capacity of Bariatric Surgery Candidates
King, WC; Engel, SG; Elder, KA; Chapman, WH; Eid, GM; Wolfe, BM; Belle, SH
2011-01-01
Background This study characterizes the walking limitations of bariatric surgery candidates by age and body mass index (BMI) and determines factors independently associated with walking capacity. Setting Multi-institutional at research university hospitals in the United States. Methods 2458 participants of the Longitudinal Assessment of Bariatric Surgery study (age: 18-78 y, BMI: 33-94 kg/m2) attended a pre-operative research visit. Walking capacity was measured via self-report and the 400 meter Long Distance Corridor Walk (LDCW). Results Almost two-thirds (64%) of subjects reported limitations walking several blocks, 48% had an objectively-defined mobility deficit, and 16% reported at least some walking aid use. In multivariable analysis, BMI, older age, lower income and greater bodily pain were independently associated (p<.05) with walking aid use, physical discomfort during the LDCW, inability to complete the LDCW, and slower time to complete the LDCW. Female sex, Hispanic ethnicity (but not race), higher resting heart rate, history of smoking, several comoribidities (history of stroke, ischemic heart disease, diabetes, asthma, sleep apnea, venous edema with ulcerations), and depressive symptoms were also independently related (p<.05) to at least one measure of reduced walking capacity. Conclusions Walking limitations are common in bariatric surgery candidates, even among the least severely obese and youngest patients. Physical activity counseling must be tailored to individuals' abilities. While several factors identified in this study (e.g., BMI, age, pain, comorbidities) should be considered, directly assessing walking capacity will facilitate appropriate goal-setting. PMID:21937285
Quantum search with multiple walk steps per oracle query
NASA Astrophysics Data System (ADS)
Wong, Thomas G.; Ambainis, Andris
2015-08-01
We identify a key difference between quantum search by discrete- and continuous-time quantum walks: a discrete-time walk typically performs one walk step per oracle query, whereas a continuous-time walk can effectively perform multiple walk steps per query while only counting query time. As a result, we show that continuous-time quantum walks can outperform their discrete-time counterparts, even though both achieve quadratic speedups over their corresponding classical random walks. To provide greater equity, we allow the discrete-time quantum walk to also take multiple walk steps per oracle query while only counting queries. Then it matches the continuous-time algorithm's runtime, but such that it is a cubic speedup over its corresponding classical random walk. This yields a greater-than-quadratic speedup for quantum search over its corresponding classical random walk.
Quantum Search with Multiple Walk Steps per Oracle Query
Thomas G. Wong; Andris Ambainis
2015-07-22
We identify a key difference between quantum search by discrete- and continuous-time quantum walks: a discrete-time walk typically performs one walk step per oracle query, whereas a continuous-time walk can effectively perform multiple walk steps per query while only counting query time. As a result, we show that continuous-time quantum walks can outperform their discrete-time counterparts, even though both achieve quadratic speedups over their corresponding classical random walks. To provide greater equity, we allow the discrete-time quantum walk to also take multiple walk steps per oracle query while only counting queries. Then it matches the continuous-time algorithm's runtime, but such that it is a cubic speedup over its corresponding classical random walk. This yields the first example of a greater-than-quadratic speedup for quantum search over its corresponding classical random walk.
Reuter, I.; Mehnert, S.; Leone, P.; Kaps, M.; Oechsner, M.; Engelhardt, M.
2011-01-01
Symptoms of Parkinson's disease (PD) progress despite optimized medical treatment. The present study investigated the effects of a flexibility and relaxation programme, walking, and Nordic walking (NW) on walking speed, stride length, stride length variability, Parkinson-specific disability (UPDRS), and health-related quality of life (PDQ 39). 90 PD patients were randomly allocated to the 3 treatment groups. Patients participated in a 6-month study with 3 exercise sessions per week, each lasting 70?min. Assessment after completion of the training showed that pain was reduced in all groups, and balance and health-related quality of life were improved. Furthermore, walking, and Nordic walking improved stride length, gait variability, maximal walking speed, exercise capacity at submaximal level, and PD disease-specific disability on the UPDRS in addition. Nordic walking was superior to the flexibility and relaxation programme and walking in improving postural stability, stride length, gait pattern and gait variability. No significant injuries occurred during the training. All patients of the Nordic walking group continued Nordic walking after completing the study. PMID:21603199
Dynamics of walking adaptation aftereffects induced in static images of walking actors.
Barraclough, Nick E; Ingham, Jennifer; Page, Stephen A
2012-04-15
Visual adaptation to walking actions results in subsequent aftereffects that bias perception of static images of walkers in different postures so that they are interpreted as walking in the opposite direction to the adapting actor. It is not clear, however, if the walking aftereffect is comparable to other well studied low- and high-level visual aftereffects. We therefore measured the dynamics of the walking aftereffect in order to assess the characteristics of the adapting mechanism. We found that walking aftereffects showed similar characteristic dynamics as for face aftereffects and some motion aftereffects. Walking aftereffects could be induced in a broad range of different static images of walking actors and were not restricted to images of actors in any particular posture. Walking aftereffects increased with adapting stimulus repetition and declined over time. The duration of the aftereffect was dependent upon time spent observing the adapting stimulus and could be well modelled by a power-law function that characterises this relationship in both face and motion aftereffects. Increasing the speed of the adapting stimulus by increasing actor walk speed increased aftereffect magnitude, as seen for some motion aftereffects. The nature of the aftereffects induced by observing walking actors indicates that they behave like traditional high-level visual aftereffects. PMID:22406522
NASA Astrophysics Data System (ADS)
Reynolds, A. M.
2009-03-01
Recently it has been found that composite Brownian walk searches are more efficient than any Lévy walk when searching is non-destructive and when the Lévy walks are not responsive to conditions found in the search. Here a new class of adaptive Lévy walk searches is presented that encompasses composite Brownian walks as a special case. In these new models, bouts of Lévy walk searching alternate with bouts of more intensive Brownian walk searching. Switching from extensive to intensive searching is prompted by the detection of a target. And here, switching back to extensive searching arises if a target is not located after travelling a distance equal to the ‘giving-up distance’. It is found that adaptive Lévy walks outperform composite Brownian walks when searching for sparsely distributed resources. Consequently there is stronger selection pressures for Lévy processes when resources are sparsely distributed within unpredictable environments. The findings reconcile Lévy walk search theory with the ubiquity of two modes of searching by predators and with their switching search mode immediately after finding a prey.
Reuter, I; Mehnert, S; Leone, P; Kaps, M; Oechsner, M; Engelhardt, M
2011-01-01
Symptoms of Parkinson's disease (PD) progress despite optimized medical treatment. The present study investigated the effects of a flexibility and relaxation programme, walking, and Nordic walking (NW) on walking speed, stride length, stride length variability, Parkinson-specific disability (UPDRS), and health-related quality of life (PDQ 39). 90 PD patients were randomly allocated to the 3 treatment groups. Patients participated in a 6-month study with 3 exercise sessions per week, each lasting 70?min. Assessment after completion of the training showed that pain was reduced in all groups, and balance and health-related quality of life were improved. Furthermore, walking, and Nordic walking improved stride length, gait variability, maximal walking speed, exercise capacity at submaximal level, and PD disease-specific disability on the UPDRS in addition. Nordic walking was superior to the flexibility and relaxation programme and walking in improving postural stability, stride length, gait pattern and gait variability. No significant injuries occurred during the training. All patients of the Nordic walking group continued Nordic walking after completing the study. PMID:21603199
Walking dreams in congenital and acquired paraplegia.
Saurat, Marie-Thérèse; Agbakou, Maité; Attigui, Patricia; Golmard, Jean-Louis; Arnulf, Isabelle
2011-12-01
To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4-64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep. PMID:21704532
Factors influencing whether children walk to school.
Su, Jason G; Jerrett, Michael; McConnell, Rob; Berhane, Kiros; Dunton, Genevieve; Shankardass, Ketan; Reynolds, Kim; Chang, Roger; Wolch, Jennifer
2013-07-01
Few studies have simultaneously evaluated multiple levels of influence on whether children walk to school. A large cohort of 4338 subjects from 10 communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children. PMID:23707968
Factors Influencing Whether Children Walk to School
Su, Jason G.; Jerrett, Michael; Mcconnell, Rob; Berhane, Kiros; Dunton, Genevieve; Shankardass, Ketan; Reynolds, Kim; Chang, Roger; Wolch, Jennifer
2015-01-01
Few studies have evaluated multiple levels of influence simultaneously on whether children walk to school. A large cohort of 4,338 subjects from ten communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children. PMID:23707968
Symbolic walk in regular networks
NASA Astrophysics Data System (ADS)
Ermann, Leonardo; Carlo, Gabriel G.
2015-01-01
We find that a symbolic walk (SW)—performed by a walker with memory given by a Bernoulli shift—is able to distinguish between the random or chaotic topology of a given network. We show this result by means of studying the undirected baker network, which is defined by following the Ulam approach for the baker transformation in order to introduce the effect of deterministic chaos into its structure. The chaotic topology is revealed through the central role played by the nodes associated with the positions corresponding to the shortest periodic orbits of the generating map. They are the overwhelmingly most visited nodes in the limit cycles at which the SW asymptotically arrives. Our findings contribute to linking deterministic chaotic dynamics with the properties of networks constructed using the Ulam approach.
Medical Aspects of Space Walking
NASA Technical Reports Server (NTRS)
Musgrave, Story
1999-01-01
Dr. Musgrave has acquired extensive experience during a distinguished and impressive career that includes flying as an astronaut on six Shuttle missions, participating in many hours of extravehicular activity, and contributing his myriad talents toward great public service, especially in the area of education. He has a unique perspective as a physician, scientist, engineer, pilot, and scholar. His interests and breadth of knowledge, which astound even the seasoned space enthusiast, have provided the space program an extraordinary scientific and technical expertise. Dr. Musgrave presented a personal perspective on space flight with particular emphasis on extravehicular activity (EVA or space walking), which was copiously illustrated with photographs from many space missions. His theme was two fold: the exacting and detailed preparations required for successful execution of a mission plan and a cosmic view of mankind's place in the greater scheme of things.
Nonfixation for Activated Random Walks
Eric Shellef
2010-12-25
We consider the activated random walk (ARW) model where particles follow the path of a general Markov process on a general graph. We prove ARW dominates a simpler process, multiple source internal aggregation (MSIA), and use this to formulate a deterministic sufficient condition on initial occupations for nonfixation of ARW and similar variants. In particular, on bounded degree graphs, initial occupation density greater than one almost surely implies nonfixation, where independence requirements are weakened to ergodic in the case of Euclidean lattices. We show that for Euclidean lattices of dimension lower than five, initial density of exactly one also implies nonfixation. Finally, we prove the critical density for the infinite sleep rate ARW is positive for all dimensions.
Evanescence in Coined Quantum Walks
Carteret, H A; Temme, N; Carteret, Hilary A.; Richmond, Bruce; Temme, Nico
2005-01-01
In this paper we complete the analysis begun by two of the authors in a previous work on the discrete quantum walk on the line [J. Phys. A 36:8775-8795 (2003) quant-ph/0303105 ]. We obtain uniformly convergent asymptotics for the "exponential decay'' region in the Schr{\\"o}dinger (or wave-mechanics) picture. In so doing, we rigorously establish the full Feynman equivalence between the path-integral and wave-mechanics representations for this system; taken together with the previous work, we can now prove every theorem by both routes. This calculation required us to generalise the method of stationary phase and we describe this extension in some detail, including self-contained proofs of all the technical lemmas required.
Evanescence in Coined Quantum Walks
Hilary A. Carteret; Bruce Richmond; Nico Temme
2005-11-01
In this paper we complete the analysis begun by two of the authors in a previous work on the discrete quantum walk on the line [J. Phys. A 36:8775-8795 (2003) quant-ph/0303105 ]. We obtain uniformly convergent asymptotics for the "exponential decay'' regions at the leading edges of the main peaks in the Schr{\\"o}dinger (or wave-mechanics) picture. This calculation required us to generalise the method of stationary phase and we describe this extension in some detail, including self-contained proofs of all the technical lemmas required. We also rigorously establish the exact Feynman equivalence between the path-integral and wave-mechanics representations for this system using some techniques from the theory of special functions. Taken together with the previous work, we can now prove every theorem by both routes.
Quantum walks in curved spacetime
Pablo Arrighi; Stefano Facchini; Marcelo Forets
2015-05-26
A discrete-time Quantum Walk (QW) is essentially a unitary operator driving the evolution of a single particle on the lattice. Some QWs admit a continuum limit, leading to familiar PDEs (e.g. the Dirac equation), and thus provide us with discrete toy models of familiar particles (e.g. the electron). In this paper, we study the continuum limit of a wide class of QWs, and show that it leads to all those PDEs corresponding to the Hamiltonian form of the massive curved Dirac equation in (1 + 1) dimensions. Therefore a certain QW, which we make explicit, provides us with a unitary discrete toy model of the electron as a test particle in curved spacetime, in spite of the fixed background lattice. Mathematically we have introduced two novel ingredients for taking the continuum limit of a QW, but which apply to any quantum cellular automata: encoding and grouping.
Random Walk with Shrinking Steps
P. L. Krapivsky; S. Redner
2003-10-19
We outline basic properties of a symmetric random walk in one dimension, in which the length of the nth step equals lambda^n, with lambdasteps N-->oo, the probability that the endpoint is at x, P_{lambda}(x;N), approaches a limiting distribution P_{lambda}(x) that has many beautiful features. For lambda<1/2, the support of P_{lambda}(x) is a Cantor set. For 1/2<=lambda<1, there is a countably infinite set of lambda values for which P_{lambda}(x) is singular, while P_{lambda}(x) is smooth for almost all other lambda values. In the most interesting case of lambda=(sqrt{5}-1)/2=g, P_g(x) is riddled with singularities and is strikingly self-similar. The self-similarity is exploited to derive a simple form for the probability measure M(a,b)= int_a^b P_g(x) dx.
Dynamical continuous time random walk
NASA Astrophysics Data System (ADS)
Liu, Jian; Yang, Bo; Chen, Xiaosong; Bao, Jing-Dong
2015-04-01
We consider a continuous time random walk model in which each jump is considered to be dynamical process. Dissipative launch velocity and hopping time in each jump is the key factor in this model. Within the model, normal diffusion and anomalous diffusion is realized theoretically and numerically in the force free potential. Besides, external potential can be introduced naturally, so the random walker's behavior in the linear potential and quartic potential is discussed, especially the walker with Lévy velocity in the quartic potential, bimodal behavior of the spatial distribution is observed, it is shown that due to the inertial effect induced by damping term, there exists transition from unimodality to bimodality for the walker's spatial stationary distribution.
WALKING DIRECTIONS From the UHS Medical Center Office
Cantlon, Jessica F.
WALKING DIRECTIONS From the UHS Medical Center Office to the UHS Building on the River Campus Updated 5/2/12 University Health Service (UHS) in 1-5077 WALKING DIRECTIONS From the UHS Medical Center intersection. 2. Walk to the end of the hallway. Go down the stairs on your RIGHT. 3. Walk through the Flaum
Urban Walking and the Pedagogies of the Street
ERIC Educational Resources Information Center
Bairner, Alan
2011-01-01
Drawing upon the extensive literature on urban walking and also on almost 60 years' experience of walking the streets, this article argues that there is a pressing need to re-assert the educational value of going for a walk. After a brief discussion of the social significance of the "flaneur," the historic pioneer of urban walking, the article…
BLOGS // AUTOMATON Cornell's Ranger Robot Breaks New Walking Record
Ruina, Andy L.
BLOGS // AUTOMATON Cornell's Ranger Robot Breaks New Walking Record POSTED BY: COURTNEY BOYD MYERS month for walking 23 kilometers (14.3 miles), untethered, in 10 hours and 40 minutes. Walking 108.5 times, taking 65,185 steps before it had to stop and recharge. Ranger walks much like a human
Online ZMP Sampling Search for Biped Walking Planning
Veloso, Manuela M.
Online ZMP Sampling Search for Biped Walking Planning Jinsu Liu1,2 and Manuela Veloso2 1 Computer present a new method that uses random search for online planning of biped walking, given a feasible to solve the walking problem. We consider walk planning as the choice of a sequence of ZMPs leading
Walking and Eating Behavior of Toddlers at 12 Months Old
ERIC Educational Resources Information Center
Koda, Naoko; Akimoto, Yuko; Hirose, Toshiya; Hinobayashi, Toshihiko; Minami, Tetsuhiro
2004-01-01
Locomotive and eating behavior of 52 toddlers was observed at 12 months old in a nursery school and investigated in relation to the acquisition of independent walking. The toddlers who acquired walking ate more by themselves using the hands than the toddlers who did not start walking. This suggested that acquisition of walking was associated with…
First Steps Toward Underactuated Human-Inspired Bipedal Robotic Walking
Ames, Aaron
First Steps Toward Underactuated Human-Inspired Bipedal Robotic Walking Aaron D. Ames Abstract walking data, we find that specific outputs of the human, i.e., functions of the kinematics, appear to be canonical to walking and are all characterized by a single function of time, termed a human walking function
APPROXIMATING THE RANDOM WALK USING THE CENTRAL LIMIT THEOREM
May, J. Peter
, if one considers only even steps then the simple random walk is aperiodic, so the results of this paperAPPROXIMATING THE RANDOM WALK USING THE CENTRAL LIMIT THEOREM MITCH HILL Abstract. This paper will define the random walk on an integer lattice and will approximate the probability that the random walk
EINSTEIN'S RANDOM WALK AND THERMAL DIFFUSION YONG-JUNG KIM
Kim, Yong Jung
EINSTEIN'S RANDOM WALK AND THERMAL DIFFUSION YONG-JUNG KIM Abstract. Thermal diffusion has been, the physics of thermal diffusion remains poorly understood. In this paper Ludwig's thermal diffusion of the random walk to reflect the temperature gradient of thermal diffusion. Hence, the walk length and the walk
Limit Theorems For the Grover Walk Without Memory
Clement Ampadu
2011-08-20
We consider the Grover walk as a 4-state quantum walk without memory in one dimension. The walker in our 4-state quantum walk moves to the left or right. We compute the stationary distribution of the walk, in addition, we obtain the weak limit theorem
Quantum walks with neutral atoms GDR -IQFA, 5th Colloquium
Vallette, Bruno
) Walk Step = Digital Quantum Walks /2 pulse pulse #12;· Splitting a Single Atom Position time Walk Primitive | = | = #12;visualizing a ,,split" atom (trajectory) (and quantum projection postulateQuantum walks with neutral atoms GDR - IQFA, 5th Colloquium Lyon, 18. November 2014 D. Meschede
[Walking assist robot and its clinical application].
Kakou, Hiroaki; Shitama, Hideo; Kimura, Yoshiko; Nakamoto, Yoko; Furuta, Nami; Honda, Kanae; Wada, Futoshi; Hachisuka, Kenji
2009-06-01
The walking assist robot was developed to improve gait disturbance in patients with severe disabilities. The robot had a trunk supporter, power generator and operating arms which held patient's lower extremities and simulated walking, a control unit, biofeedback system, and a treadmill. We applied the robot-aided gait training to three patients with severe gait disturbance induced by stroke, axonal Guillan-Barré syndrome or spinal cord injury, and the walking assist robot turned out to be effective in improving the gait disturbance. PMID:19530565
Localized quantum walks as secured quantum memory
C. M. Chandrashekar; Th. Busch
2015-04-21
We show that a quantum walk process can be used to construct and secure quantum memory. More precisely, we show that a localized quantum walk with temporal disorder can be engineered to store the information of a single, unknown qubit on a compact position space and faithfully recover it on demand. Since the localization occurss with a finite spread in position space, the stored information of the qubit will be naturally secured from the simple eavesdropper. Our protocol can be adopted to any quantum system for which experimental control over quantum walk dynamics can be achieved.
Universal computation by multiparticle quantum walk.
Childs, Andrew M; Gosset, David; Webb, Zak
2013-02-15
A quantum walk is a time-homogeneous quantum-mechanical process on a graph defined by analogy to classical random walk. The quantum walker is a particle that moves from a given vertex to adjacent vertices in quantum superposition. We consider a generalization to interacting systems with more than one walker, such as the Bose-Hubbard model and systems of fermions or distinguishable particles with nearest-neighbor interactions, and show that multiparticle quantum walk is capable of universal quantum computation. Our construction could, in principle, be used as an architecture for building a scalable quantum computer with no need for time-dependent control. PMID:23413349
Mixing in Continuous Quantum Walks on Graphs
Amir Ahmadi; Ryan Belk; Christino Tamon; Carolyn Wendler
2003-04-16
Classical random walks on well-behaved graphs are rapidly mixing towards the uniform distribution. Moore and Russell showed that a continuous quantum walk on the hypercube is instantaneously uniform mixing. We show that the continuous-time quantum walks on other well-behaved graphs do not exhibit this uniform mixing. We prove that the only graphs amongst balanced complete multipartite graphs that have the instantaneous uniform mixing property are the complete graphs on two, three and four vertices, and the cycle graph on four vertices. Our proof exploits the circulant structure of these graphs. Furthermore, we conjecture that most complete cycles and Cayley graphs lack this mixing property as well.
Decoherence can be useful in quantum walks
Kendon, Viv; Tregenna, Ben
2003-04-01
We present a study of the effects of decoherence in the operation of a discrete quantum walk on a line, cycle, and hypercube. We find high sensitivity to decoherence, increasing with the number of steps in the walk, as the particle is becoming more delocalized with each step. However, the effect of a small amount of decoherence is to enhance the properties of the quantum walk that are desirable for the development of quantum algorithms. Specifically, we observe a highly uniform distribution on the line, a very fast mixing time on the cycle, and more reliable hitting times across the hypercube.
Scaling for random walks on Eden trees
NASA Astrophysics Data System (ADS)
Aarão Reis, F. D. A.
1996-10-01
Random walks are simulated on finite stages of construction of Eden trees in dimensions D=2 and 3, and it is shown that the mean-square displacement
How do environmental factors influence walking in groups? A walk-along study.
Kassavou, Aikaterini; French, David P; Chamberlain, Kerry
2015-10-01
Insufficient attention has been given to the influence of context on health-related behaviour change. This article reports on walk-along interviews conducted with 10 leaders of walking groups while leading their groups to investigate the influence of contextual factors on walking behaviours in groups. Data analysis used ideas from thematic analysis and grounded theory, approaching the data inductively. We identified that characteristics of place influenced the type of walking that people do in groups and the processes used by walkers to make sense of their behaviours in the places they walk. This research provides insight into how place influences walking in groups. It also suggests recommendations for co-ordinators and policymakers that could be used to facilitate behaviour change, when designing interventions targeting public health within the community. PMID:24296734
Quantum random walks with decoherent coins
Brun, Todd A.; Ambainis, Andris [Institute for Advanced Study, Einstein Drive, Princeton, New Jersey 08540 (United States); Carteret, H.A. [Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)
2003-03-01
The quantum random walk has been much studied recently, largely due to its highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum walk on the line: the presence of decoherence in the quantum ''coin'' which drives the walk. We find exact analytical expressions for the time dependence of the first two moments of position, and show that in the long-time limit the variance grows linearly with time, unlike the unitary walk. We compare this to the results of direct numerical simulation, and see how the form of the position distribution changes from the unitary to the usual classical result as we increase the strength of the decoherence.
Real time visualization of quantum walk
Miyazaki, Akihide; Hamada, Shinji; Sekino, Hideo
2014-02-20
Time evolution of quantum particles like electrons is described by time-dependent Schrödinger equation (TDSE). The TDSE is regarded as the diffusion equation of electrons with imaginary diffusion coefficients. And the TDSE is solved by quantum walk (QW) which is regarded as a quantum version of a classical random walk. The diffusion equation is solved in discretized space/time as in the case of classical random walk with additional unitary transformation of internal degree of freedom typical for quantum particles. We call the QW for solution of the TDSE a Schrödinger walk (SW). For observation of one quantum particle evolution under a given potential in atto-second scale, we attempt a successive computation and visualization of the SW. Using Pure Data programming, we observe the correct behavior of a probability distribution under the given potential in real time for observers of atto-second scale.
Walking for health in adolescent girls
MacDonald, Mhairi Jane
2014-07-04
Research has highlighted that adolescent girls are insufficiently active which has serious implications for their current and future health. Walking is recognised as an effective way of implementing regular, health ...
Quantum Lattice Boltzmann is a quantum walk
Sauro Succi; Francois Fillion-Gourdeau; Silvia Palpacelli
2015-04-13
Numerical methods for the 1-D Dirac equation based on operator splitting and on the quantum lattice Boltzmann (QLB) schemes are reviewed. It is shown that these discretizations fall within the class of quantum walks, i.e. discrete maps for complex fields, whose continuum limit delivers Dirac-like relativistic quantum wave equations. The correspondence between the quantum walk dynamics and these numerical schemes is given explicitly, allowing a connection between quantum computations, numerical analysis and lattice Boltzmann methods. The QLB method is then extended to the Dirac equation in curved spaces and it is demonstrated that the quantum walk structure is preserved. Finally, it is argued that the existence of this link between the discretized Dirac equation and quantum walks may be employed to simulate relativistic quantum dynamics on quantum computers.
Gallery Walk Questions about Human Dimensions
NSDL National Science Digital Library
created by Mark Francek, Central Michigan University The following are potential questions that could be used in a gallery walk activity about the human dimensions of geologic issues. The questions are organized ...
Network Discovery by Generalized Random Walks
A. Asztalos; Z. Toroczkai
2010-08-30
We investigate network exploration by random walks defined via stationary and adaptive transition probabilities on large graphs. We derive an exact formula valid for arbitrary graphs and arbitrary walks with stationary transition probabilities (STP), for the average number of discovered edges as function of time. We show that for STP walks site and edge exploration obey the same scaling $\\sim n^{\\lambda}$ as function of time $n$. Therefore, edge exploration on graphs with many loops is always lagging compared to site exploration, the revealed graph being sparse until almost all nodes have been discovered. We then introduce the Edge Explorer Model, which presents a novel class of adaptive walks, that perform faithful network discovery even on dense networks.
The walking cluster algorithm Internal Report
The walking cluster algorithm Internal Report Frank De Smet, Kathleen Marchal, Gert Thijs, Janick to be excluded from further analysis. With this remark in mind, we propose in this text an algorithm that tries
Walking with coffee: why does it spill?
Mayer, H C; Krechetnikov, R
2012-04-01
In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it. PMID:22680548
Walking with coffee: Why does it spill?
NASA Astrophysics Data System (ADS)
Mayer, H. C.; Krechetnikov, R.
2012-04-01
In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.
Walk, Haydel Approach to Process Heat Recovery
Waldsmith, R. W.; Hendrickson, M. J.
1983-01-01
Walk, Haydel has developed a two phase approach to optimize the recovery of process heat in energy intensive operations. While the approach can be used on 'grassroots' designs, it has been used primarily for revamps. The ...
Steering random walks with kicked ultracold atoms
NASA Astrophysics Data System (ADS)
Weiß, Marcel; Groiseau, Caspar; Lam, W. K.; Burioni, Raffaella; Vezzani, Alessandro; Summy, Gil S.; Wimberger, Sandro
2015-09-01
The kicking sequence of the atom-optics kicked rotor at quantum resonance can be interpreted as a quantum random walk in momentum space. We show how such a walk can become the basis for nontrivial classical walks by applying a random sequence of intensities and phases of the kicking lattice chosen according to a probability distribution. This distribution converts on average into the final momentum distribution of the kicked atoms. In particular, it is shown that a power-law distribution for the kicking strengths results in a Lévy walk in momentum space and in a power law with the same exponent in the averaged momentum distribution. Furthermore, we investigate the stability of our predictions in the context of a realistic experiment with Bose-Einstein condensates.
Minimal walking technicolor: Setup for collider physics
Foadi, Roshan; Frandsen, Mads T.; Ryttov, Thomas A.; Sannino, Francesco [CERN Theory Division, CH-1211 Geneva 23 (Switzerland); University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)
2007-09-01
Different theoretical and phenomenological aspects of the minimal and nonminimal walking technicolor theories have recently been studied. The goal here is to make the models ready for collider phenomenology. We do this by constructing the low energy effective theory containing scalars, pseudoscalars, vector mesons, and other fields predicted by the minimal walking theory. We construct their self-interactions and interactions with standard model fields. Using the Weinberg sum rules, opportunely modified to take into account the walking behavior of the underlying gauge theory, we find interesting relations for the spin-one spectrum. We derive the electroweak parameters using the newly constructed effective theory and compare the results with the underlying gauge theory. Our analysis is sufficiently general such that the resulting model can be used to represent a generic walking technicolor theory not at odds with precision data.
Epidemic spreading driven by biased random walks
NASA Astrophysics Data System (ADS)
Pu, Cunlai; Li, Siyuan; Yang, Jian
2015-08-01
Random walk is one of the basic mechanisms of many network-related applications. In this paper, we study the dynamics of epidemic spreading driven by biased random walks in complex networks. In our epidemic model, infected nodes send out infection packets by biased random walks to their neighbor nodes, and this causes the infection of susceptible nodes that receive the packets. Infected nodes recover from the infection at a constant rate ?, and will not be infected again after recovery. We obtain the largest instantaneous number of infected nodes and the largest number of ever-infected nodes respectively, by tuning the parameter ? of the biased random walks. Simulation results on model and real-world networks show that spread of the epidemic becomes intense and widespread with increase of either delivery capacity of infected nodes, average node degree, or homogeneity of node degree distribution.
Care and Operation of Walk-Ins.
ERIC Educational Resources Information Center
Bauer, James M.
1979-01-01
Problems of owners who use their walk-in coolers and freezers only part of the year demand special consideration. Proper techniques for startup, operation, and shutdown must be used to guarantee efficient, inexpensive operation. (Author)
Momentum Dynamics of One Dimensional Quantum Walks
Ian Fuss; Langord B. White; Peter J. Sherman; Sanjeev Naguleswaran
2006-05-24
We derive the momentum space dynamic equations and state functions for one dimensional quantum walks by using linear systems and Lie group theory. The momentum space provides an analytic capability similar to that contributed by the z transform in discrete systems theory. The state functions at each time step are expressed as a simple sum of three Chebyshev polynomials. The functions provide an analytic expression for the development of the walks with time.
Standardized Questionnaires of Walking & Bicycling Database
This database contains questionnaire items and a list of validation studies for standardized items concerning walking and biking from multiple national and international physical activity questionnaires (PAQs). The purpose of this database is to provide easy access to a large number of items assessing duration and frequency of walking and bicycling in the non-disabled adult population. We also briefly review the results of validation studies identified for some of the PAQs.
Mesonic spectroscopy of minimal walking technicolor
Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino; Pica, Claudio; Rago, Antonio
2010-07-01
We investigate the structure and the novel emerging features of the mesonic nonsinglet spectrum of the minimal walking technicolor theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD-like theory. Our results favor a scenario in which minimal walking technicolor is (almost) conformal in the infrared, while spontaneous chiral symmetry breaking seems less plausible.
Partially labeled classification with Markov random walks
Martin Szummer; Tommi Jaakkola
2001-01-01
Abstract To classify a large number,of unlabeled examples,we combine,a limited number,of labeled examples with a Markov random,walk representation over the unlabeled examples. The random,walk representation exploits any low dimensional structure in the data in a robust, probabilistic manner. We develop and compare,several estimation criteria\\/algorithms suited to this representation. This includes in particular multi-way classification with an average margin criterion which
Stochasticity, invasions, and branching random walks.
Kot, Mark; Medlock, Jan; Reluga, Timothy; Walton, D Brian
2004-11-01
We link deterministic integrodifference equations to stochastic, individual-based simulations by means of branching random walks. Using standard methods, we determine speeds of invasion for both average densities and furthest-forward individuals. For density-independent branching random walks, demographic stochasticity can produce extinction. Demographic stochasticity does not, however, reduce the overall asymptotic speed of invasion or preclude continually accelerating invasions. PMID:15465119
Code of Federal Regulations, 2011 CFR
2011-01-01
...measurement of energy consumption of walk-in coolers and walk-in freezers. 431.304...COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers Test Procedures...measurement of energy consumption of walk-in coolers and walk-in freezers. (a)...
Exploring scalar quantum walks on Cayley graphs
Olga Lopez Acevedo; Jérémie Roland; Nicolas J. Cerf
2006-09-30
A quantum walk, \\emph{i.e.}, the quantum evolution of a particle on a graph, is termed \\emph{scalar} if the internal space of the moving particle (often called the coin) has a dimension one. Here, we study the existence of scalar quantum walks on Cayley graphs, which are built from the generators of a group. After deriving a necessary condition on these generators for the existence of a scalar quantum walk, we present a general method to express the evolution operator of the walk, assuming homogeneity of the evolution. We use this necessary condition and the subsequent constructive method to investigate the existence of scalar quantum walks on Cayley graphs of various groups presented with two or three generators. In this restricted framework, we classify all groups -- in terms of relations between their generators -- that admit scalar quantum walks, and we also derive the form of the most general evolution operator. Finally, we point out some interesting special cases, and extend our study to a few examples of Cayley graphs built with more than three generators.
A trajectory equation for walking droplets
NASA Astrophysics Data System (ADS)
Oza, Anand; Rosales, Rodolfo; Bush, John
2012-11-01
Yves Couder and coworkers have demonstrated phenomena reminiscent of quantum mechanics in a macroscopic hydrodynamic system. Specifically, they have discovered that millimetric droplets walking on a vibrating fluid bath exhibit wave-particle phenomena previously thought to be peculiar to the microscopic quantum realm, including single-particle diffraction and tunneling. Orbital quantization may be observed by placing a walking drop on a rotating fluid bath, which suggests a correspondence between the drop's quantized orbits and the Landau levels of an electron in a uniform magnetic field. We here develop an integro-differential trajectory equation for these walking droplets with a view to gaining insight into their subtle dynamics. We present an exact formula for the walking speed and compare it to experimental data. We also analyze the stability of the walking solution to infinitesimal perturbations. The trajectory equation is used to model the walking drop in a rotating fluid bath, which allows us to rationalize the observed orbital quantization. We predict the existence of self-orbiting or ``spin'' states and a mechanism reminiscent of the Zeeman effect in quantum mechanics.
Coined quantum walks on percolation graphs
Godfrey Leung; Paul Knott; Joe Bailey; Viv Kendon
2010-10-26
Quantum walks, both discrete (coined) and continuous time, form the basis of several quantum algorithms and have been used to model processes such as transport in spin chains and quantum chemistry. The enhanced spreading and mixing properties of quantum walks compared with their classical counterparts have been well-studied on regular structures and also shown to be sensitive to defects and imperfections in the lattice. As a simple example of a disordered system, we consider percolation lattices, in which edges or sites are randomly missing, interrupting the progress of the quantum walk. We use numerical simulation to study the properties of coined quantum walks on these percolation lattices in one and two dimensions. In one dimension (the line) we introduce a simple notion of quantum tunneling and determine how this affects the properties of the quantum walk as it spreads. On two-dimensional percolation lattices, we show how the spreading rate varies from linear in the number of steps down to zero, as the percolation probability decreases to the critical point. This provides an example of fractional scaling in quantum walk dynamics.
Convergence of quantum random walks with decoherence
Fan Shimao; Feng Zhiyong; Yang, Wei-Shih; Xiong Sheng
2011-10-15
In this paper, we study the discrete-time quantum random walks on a line subject to decoherence. The convergence of the rescaled position probability distribution p(x,t) depends mainly on the spectrum of the superoperator L{sub kk}. We show that if 1 is an eigenvalue of the superoperator with multiplicity one and there is no other eigenvalue whose modulus equals 1, then P(({nu}/{radical}(t)),t) converges to a convex combination of normal distributions. In terms of position space, the rescaled probability mass function p{sub t}(x,t){identical_to}p({radical}(t)x,t), x is an element of Z/{radical}(t), converges in distribution to a continuous convex combination of normal distributions. We give a necessary and sufficient condition for a U(2) decoherent quantum walk that satisfies the eigenvalue conditions. We also give a complete description of the behavior of quantum walks whose eigenvalues do not satisfy these assumptions. Specific examples such as the Hadamard walk and walks under real and complex rotations are illustrated. For the O(2) quantum random walks, an explicit formula is provided for the scaling limit of p(x,t) and their moments. We also obtain exact critical exponents for their moments at the critical point and show universality classes with respect to these critical exponents.
NASA Technical Reports Server (NTRS)
Whittaker, William; Dowling, Kevin
1994-01-01
Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.
Holographic Walking from Tachyon DBI
David Kutasov; Jennifer Lin; Andrei Parnachev
2012-03-13
We use holography to study Conformal Phase Transitions, which are believed to be realized in four dimensional QCD and play an important role in walking technicolor models of electroweak symmetry breaking. At strong coupling they can be modeled by the non-linear dynamics of a tachyonic scalar field with mass close to the Breitenlohner-Freedman bound in anti de Sitter spacetime. Taking the action for this field to have a Tachyon-Dirac-Born-Infeld form gives rise to models that resemble hard and soft wall AdS/QCD, with a dynamically generated wall. For hard wall models, the highly excited spectrum has the KK form m_n ~ n; in the soft wall case we exhibit potentials with m_n ~ n^\\alpha, 0<\\alpha\\leq1/2. We investigate the finite temperature phase structure and find first or second order symmetry restoration transitions, depending on the behavior of the potential near the origin of field space.
Adaptive Walking in Alzheimer's Disease
Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken
2012-01-01
The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients. PMID:22991684
Adaptive walking in Alzheimer's disease.
Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken
2012-01-01
The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients. PMID:22991684
Infinite densities for Lévy walks
Adi Rebenshtok; Sergey Denisov; Peter Hanggi; Eli Barkai
2014-12-01
Motion of particles in many systems exhibits a mixture between periods of random diffusive like events and ballistic like motion. In many cases, such systems exhibit strong anomalous diffusion, where low order moments $$ with $q$ below a critical value $q_c$ exhibit diffusive scaling while for $q>q_c$ a ballistic scaling emerges. The mixed dynamics constitutes a theoretical challenge since it does not fall into a unique category of motion, e.g., the known diffusion equations and central limit theorems fail to describe both aspects. In this paper we resolve this problem by resorting to the concept of infinite density. Using the widely applicable L\\'evy walk model, we find a general expression for the corresponding non-normalized density which is fully determined by the particles velocity distribution, the anomalous diffusion exponent $\\alpha$ and the diffusion coefficient $K_\\alpha$. We explain how infinite densities play a central role in the description of dynamics of a large class of physical processes and discuss how they can be evaluated from experimental or numerical data.
NASA Astrophysics Data System (ADS)
Whittaker, William; Dowling, Kevin
1994-03-01
Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.
Torque-stiffness-controlled dynamic walking with central pattern generators.
Huang, Yan; Vanderborght, Bram; Van Ham, Ronald; Wang, Qining
2014-12-01
Walking behavior is modulated by controlling joint torques in most existing passivity-based bipeds. Controlled Passive Walking with adaptable stiffness exhibits controllable natural motions and energy efficient gaits. In this paper, we propose torque-stiffness-controlled dynamic bipedal walking, which extends the concept of Controlled Passive Walking by introducing structured control parameters and a bio-inspired control method with central pattern generators. The proposed walking paradigm is beneficial in clarifying the respective effects of the external actuation and the internal natural dynamics. We present a seven-link biped model to validate the presented walking. Effects of joint torque and joint stiffness on gait selection, walking performance and walking pattern transitions are studied in simulations. The work in this paper develops a new solution of motion control of bipedal robots with adaptable stiffness and provides insights of efficient and sophisticated walking gaits of humans. PMID:25128320
Nordic walking practice might improve plantar pressure distribution.
Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Martínez-Nova, Alfonso; Morey-Klapsing, G; Encarnación-Martínez, Alberto
2011-12-01
Nordic walking (NW), characterized by the use of two walking poles, is becoming increasingly popular (Morgulec-Adamowicz, Marszalek, & Jagustyn, 2011). We studied walking pressure patterns of 20 experienced and 30 beginner Nordic walkers. Plantar pressures from nine foot zones were measured during trials performed at two walking speeds (preferred and 20% faster), and under two walking conditions (NW vs. normal walking). In comparison to normal walking, NW experience led to a significant (p < .05) pressure reduction of about 50% on the central metatarsals. No significant increases were detected in other foot regions. The differences between experienced and beginners during normal walking including a 40% pressure reduction on the metatarsal area, suggests that regular NW practice might also have a beneficial effect on plantar pressure when walking without poles. PMID:22276400
One dimensional lazy quantum walks and occupancy rate
Dan Li; Michael Mc Gettrick; Wei-Wei Zhang; Ke-Jia Zhang
2014-12-22
Lazy quantum walks were presented by Andrew M. Childs to prove that the continuous-time quantum walk is a limit of the discrete-time quantum walk [Commun.Math.Phys.294,581-603(2010)]. In this paper, we discuss properties of lazy quantum walks. Our analysis shows that lazy quantum walks have $O(t^n)$ order of the n-th moment of the corresponding probability distribution, which is the same as that for normal quantum walks. Also, the lazy quantum walk with DFT (Discrete Fourier Transform) coin operator has a similar probability distribution concentrated interval to that of the normal Hadamard quantum walk. Most importantly, we introduce the concepts of occupancy number and occupancy rate to measure the extent to which the walk has a (relatively) high probability at every position in its range. We conclude that lazy quantum walks have a higher occupancy rate than other walks such as normal quantum walks, classical walks and lazy classical walks.
Predicting the metabolic cost of incline walking from muscle activity and walking mechanics
Delp, Scott
model including only the peak knee flexion angle during stance phase, peak knee extension moment, peak with inclined walking. Musculoskeletal simulations often estimate muscle acti- vation patterns during walking using an objective function that minimizes the sum of squared simulated muscle activations (Anderson
Walking on fractals: diffusion and self-avoiding walks on percolation clusters
Viktoria Blavatska; Wolfhard Janke
2008-07-24
We consider random walks (RWs) and self-avoiding walks (SAWs) on disordered lattices directly at the percolation threshold. Applying numerical simulations, we study the scaling behavior of the models on the incipient percolation cluster in space dimensions d=2, 3, 4. Our analysis yields estimates of universal exponents, governing the scaling laws for configurational properties of RWs and SAWs.
Quantum Walks on Two Kinds of Two-Dimensional Models
NASA Astrophysics Data System (ADS)
Li, Dan; Mc Gettrick, Michael; Zhang, Wei-Wei; Zhang, Ke-Jia
2015-08-01
In this paper, we numerically study quantum walks on two kinds of two-dimensional graphs: cylindrical strip and Mobius strip. The two kinds of graphs are typical two-dimensional topological graph. We study the crossing property of quantum walks on these two models. Also, we study its dependence on the initial state, size of the model. At the same time, we compare the quantum walk and classical walk on these two models to discuss the difference of quantum walk and classical walk.
Walking and running at resonance.
Ahlborn, Boye K; Blake, Robert W
2002-01-01
Humans and other animals can temporarily store mechanical energy in elastic oscillations, f(el), of body parts and in pendulum oscillations, f(p) = const sq.rt (g/L), of legs, length L, or other appendages, and thereby reduce the energy consumption of locomotion. However, energy saving only occurs if these oscillations are tuned to the leg propagation frequency f. It has long been known that f is tuned to the pendulum frequency of the free-swinging leg of walkers. During running the leg frequency increases to some new value f = f(r). We propose that in order to maintain resonance the animal, mass M, actively increases its leg pendulum frequency to the new value f(p,r) =const sq.rt (a(y)/L)=f(r), by giving its hips a vertical acceleration a(y)= F(y)/M. The pendulum frequency is increased if the impact force F(y) of the stance foot is larger than Mg, explaining the observation by Alexander and Bennet-Clark (1976) that F(v) becomes larger than Mg when animals start to run. Our model predictions of the running velocity U(r) as function of L, F(v), are in agreement with measurements of these quantities (Farley et al. 1993). The leg's longitudinal elastic oscillation frequency scales as f(el) = const sq.rt (k/M). Experiments by Ferris et al., (1998) show that runners adjust their leg's stiffness, k, when running on surfaces of different elasticity so that the total stiffness k remains constant. Our analysis of their data suggests that the longitudinal oscillations of the stance leg are indeed kept in tune with the running frequency. Therefore we conclude that humans, and by extension all animals, maintain resonance during running. Our model also predicts the Froude number of walking-running transitions, Fr = U(2)/gL approximately 0.5 in good agreement with measurements. PMID:16351865
Learning to walk changes infants' social interactions.
Clearfield, Melissa W
2011-02-01
The onset of crawling marks a motor, cognitive and social milestone. The present study investigated whether independent walking marks a second milestone for social behaviors. In Experiment 1, the social and exploratory behaviors of crawling infants were observed while crawling and in a baby-walker, resulting in no differences based on posture. In Experiment 2, the social behaviors of independently walking infants were compared to age-matched crawling infants in a baby-walker. Independently walking infants spent significantly more time interacting with the toys and with their mothers, and also made more vocalizations and more directed gestures compared to infants in the walker. Experiment 3 tracked infants' social behaviors longitudinally across the transition from crawling and walking. Even when controlled for age, the transition to independent walking marked increased interaction time with mothers, as well as more sophisticated interactions, including directing mothers' attention to particular objects. The results suggest a developmental progression linking social interactions with milestones in locomotor development. PMID:20478619
Myoelectric walking mode classification for transtibial amputees.
Miller, Jason D; Beazer, Mahyo Seyedali; Hahn, Michael E
2013-10-01
Myoelectric control algorithms have the potential to detect an amputee's motion intent and allow the prosthetic to adapt to changes in walking mode. The development of a myoelectric walking mode classifier for transtibial amputees is outlined. Myoelectric signals from four muscles (tibialis anterior, medial gastrocnemius (MG), vastus lateralis, and biceps femoris) were recorded for five nonamputee subjects and five transtibial amputees over a variety of walking modes: level ground at three speeds, ramp ascent/descent, and stair ascent/descent. These signals were decomposed into relevant features (mean absolute value, variance, wavelength, number of slope sign changes, number of zero crossings) over three subwindows from the gait cycle and used to test the ability of classification algorithms for transtibial amputees using linear discriminant analysis (LDA) and support vector machine (SVM) classifiers. Detection of all seven walking modes had an accuracy of 97.9% for the amputee group and 94.7% for the nonamputee group. Misclassifications occurred most frequently between different walking speeds due to the similar nature of the gait pattern. Stair ascent/descent had the best classification accuracy with 99.8% for the amputee group and 100.0% for the nonamputee group. Stability of the developed classifier was explored using an electrode shift disturbance for each muscle. Shifting the electrode placement of the MG had the most pronounced effect on the classification accuracy for both samples. No increase in classification accuracy was observed when using SVM compared to LDA for the current dataset. PMID:23708765
Relationship Between Quantum Walk and Relativistic Quantum Mechanics
C. M. Chandrashekar; Subhashish Banerjee; R. Srikanth
2010-06-26
Quantum walk models have been used as an algorithmic tool for quantum computation and to describe various physical processes. This paper revisits the relationship between relativistic quantum mechanics and the quantum walks. We show the similarities of the mathematical structure of the decoupled and coupled form of the discrete-time quantum walk to that of the Klein-Gordon and Dirac equations, respectively. In the latter case, the coin emerges as an analog of the spinor degree of freedom. Discrete-time quantum walk as a coupled form of the continuous-time quantum walk is also shown by transforming the decoupled form of the discrete-time quantum walk to the Schrodinger form. By showing the coin to be a means to make the walk reversible, and that the Dirac-like structure is a consequence of the coin use, our work suggests that the relativistic causal structure is a consequence of conservation of information. However, decoherence (modelled by projective measurements on position space) generates entropy that increases with time, making the walk irreversible and thereby producing an arrow of time. Lieb-Robinson bound is used to highlight the causal structure of the quantum walk to put in perspective the relativistic structure of quantum walk, maximum speed of the walk propagation and the earlier findings related to the finite spread of the walk probability distribution. We also present a two-dimensional quantum walk model on a two state system to which the study can be extended.
Relationship between quantum walks and relativistic quantum mechanics
Chandrashekar, C. M.; Banerjee, Subhashish; Srikanth, R.
2010-06-15
Quantum walk models have been used as an algorithmic tool for quantum computation and to describe various physical processes. This article revisits the relationship between relativistic quantum mechanics and the quantum walks. We show the similarities of the mathematical structure of the decoupled and coupled forms of the discrete-time quantum walk to that of the Klein-Gordon and Dirac equations, respectively. In the latter case, the coin emerges as an analog of the spinor degree of freedom. Discrete-time quantum walk as a coupled form of the continuous-time quantum walk is also shown by transforming the decoupled form of the discrete-time quantum walk to the Schroedinger form. By showing the coin to be a means to make the walk reversible and that the Dirac-like structure is a consequence of the coin use, our work suggests that the relativistic causal structure is a consequence of conservation of information. However, decoherence (modeled by projective measurements on position space) generates entropy that increases with time, making the walk irreversible and thereby producing an arrow of time. The Lieb-Robinson bound is used to highlight the causal structure of the quantum walk to put in perspective the relativistic structure of the quantum walk, the maximum speed of walk propagation, and earlier findings related to the finite spread of the walk probability distribution. We also present a two-dimensional quantum walk model on a two-state system to which the study can be extended.
Universal quantum computation by discontinuous quantum walk
Underwood, Michael S.; Feder, David L. [Institute for Quantum Information Science, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)
2010-10-15
Quantum walks are the quantum-mechanical analog of random walks, in which a quantum ''walker'' evolves between initial and final states by traversing the edges of a graph, either in discrete steps from node to node or via continuous evolution under the Hamiltonian furnished by the adjacency matrix of the graph. We present a hybrid scheme for universal quantum computation in which a quantum walker takes discrete steps of continuous evolution. This ''discontinuous'' quantum walk employs perfect quantum-state transfer between two nodes of specific subgraphs chosen to implement a universal gate set, thereby ensuring unitary evolution without requiring the introduction of an ancillary coin space. The run time is linear in the number of simulated qubits and gates. The scheme allows multiple runs of the algorithm to be executed almost simultaneously by starting walkers one time step apart.
Swarming bacteria migrate by Lévy Walk.
Ariel, Gil; Rabani, Amit; Benisty, Sivan; Partridge, Jonathan D; Harshey, Rasika M; Be'er, Avraham
2015-01-01
Individual swimming bacteria are known to bias their random trajectories in search of food and to optimize survival. The motion of bacteria within a swarm, wherein they migrate as a collective group over a solid surface, is fundamentally different as typical bacterial swarms show large-scale swirling and streaming motions involving millions to billions of cells. Here by tracking trajectories of fluorescently labelled individuals within such dense swarms, we find that the bacteria are performing super-diffusion, consistent with Lévy walks. Lévy walks are characterized by trajectories that have straight stretches for extended lengths whose variance is infinite. The evidence of super-diffusion consistent with Lévy walks in bacteria suggests that this strategy may have evolved considerably earlier than previously thought. PMID:26403719
Gaussian Networks Generated by Random Walks
NASA Astrophysics Data System (ADS)
Javarone, Marco Alberto
2015-04-01
We propose a random walks based model to generate complex networks. Many authors studied and developed different methods and tools to analyze complex networks by random walk processes. Just to cite a few, random walks have been adopted to perform community detection, exploration tasks and to study temporal networks. Moreover, they have been used also to generate networks with different topologies (e.g., scale-free). In this work, we define a random walker that plays the role of "edges-generator". In particular, the random walker generates new connections and uses these ones to visit each node of a network. As result, the proposed model allows to achieve networks provided with a Gaussian degree distribution; moreover we found that some properties of achieved Gaussian networks, as the clustering coefficient and the assortativity, show a critical behavior. Finally, we performed numerical simulations to study the behavior and the properties of the cited model.
Humanoid robot Lola: design and walking control.
Buschmann, Thomas; Lohmeier, Sebastian; Ulbrich, Heinz
2009-01-01
In this paper we present the humanoid robot LOLA, its mechatronic hardware design, simulation and real-time walking control. The goal of the LOLA-project is to build a machine capable of stable, autonomous, fast and human-like walking. LOLA is characterized by a redundant kinematic configuration with 7-DoF legs, an extremely lightweight design, joint actuators with brushless motors and an electronics architecture using decentralized joint control. Special emphasis was put on an improved mass distribution of the legs to achieve good dynamic performance. Trajectory generation and control aim at faster, more flexible and robust walking. Center of mass trajectories are calculated in real-time from footstep locations using quadratic programming and spline collocation methods. Stabilizing control uses hybrid position/force control in task space with an inner joint position control loop. Inertial stabilization is achieved by modifying the contact force trajectories. PMID:19665558
Quantum random-walk search algorithm
Shenvi, Neil; Whaley, K. Birgitta; Kempe, Julia
2003-05-01
Quantum random walks on graphs have been shown to display many interesting properties, including exponentially fast hitting times when compared with their classical counterparts. However, it is still unclear how to use these novel properties to gain an algorithmic speedup over classical algorithms. In this paper, we present a quantum search algorithm based on the quantum random-walk architecture that provides such a speedup. It will be shown that this algorithm performs an oracle search on a database of N items with O({radical}(N)) calls to the oracle, yielding a speedup similar to other quantum search algorithms. It appears that the quantum random-walk formulation has considerable flexibility, presenting interesting opportunities for development of other, possibly novel quantum algorithms.
Fast Scramblers, Democratic Walks and Information Fields
Javier M. Magan
2015-07-09
We study a family of weighted random walks on complete graphs. These `democratic walks' turn out to be explicitly solvable, and we find the hierarchy window for which the characteristic time scale saturates the so-called fast scrambling conjecture. We show that these democratic walks describe well the properties of information spreading in systems in which every degree of freedom interacts with every other degree of freedom, such as Matrix or infinite range models. The argument is based on the analysis of suitably defined `Information fields' ($\\mathcal{I}$), which are shown to evolve stochastically towards stationarity due to unitarity of the microscopic model. The model implies that in democratic systems, stabilization of one subsystem is equivalent to global scrambling. We use these results to study scrambling of infalling perturbations in black hole backgrounds, and argue that the near horizon running coupling constants are connected to entanglement evolution of single particle perturbations in democratic systems.
Fast Scramblers, Democratic Walks and Information Fields
Magan, Javier M
2015-01-01
We study a family of weighted random walks on complete graphs. These `democratic walks' turn out to be explicitly solvable, and we find the hierarchy window for which the characteristic time scale saturates the so-called fast scrambling conjecture. We show that these democratic walks describe well the properties of information spreading in systems in which every degree of freedom interacts with every other degree of freedom, such as Matrix or infinite range models. The argument is based on the analysis of suitably defined `Information fields' ($\\mathcal{I}$), which are shown to evolve stochastically towards stationarity due to unitarity of the microscopic model. The model implies that in democratic systems, stabilization of one subsystem is equivalent to global scrambling. We use these results to study scrambling of infalling perturbations in black hole backgrounds, and argue that the near horizon running coupling constants are connected to entanglement evolution of single particle perturbations in democratic...
Steering random walks with kicked ultracold atoms
Weiß, Marcel; Lam, W K; Burioni, Raffaella; Vezzani, Alessandro; Summy, Gil S; Wimberger, Sandro
2015-01-01
A kicking sequence of the atom optics kicked rotor at quantum resonance can be interpreted as a quantum random walk in momentum space. We show how to steer such a random walk by applying a random sequence of intensities and phases of the kicking lattice chosen according to a probability distribution. This distribution converts on average into the final momentum distribution of the kicked atoms. In particular, it is shown that a power-law distribution for the kicking strengths results in a L\\'evy walk in momentum space and in a power-law with the same exponent in the averaged momentum distribution. Furthermore, we investigate the stability of our predictions in the context of a realistic experiment with Bose-Einstein condensates.
Steering random walks with kicked ultracold atoms
Marcel Weiß; Caspar Groiseau; W. K. Lam; Raffaella Burioni; Alessandro Vezzani; Gil S. Summy; Sandro Wimberger
2015-06-27
A kicking sequence of the atom optics kicked rotor at quantum resonance can be interpreted as a quantum random walk in momentum space. We show how to steer such a random walk by applying a random sequence of intensities and phases of the kicking lattice chosen according to a probability distribution. This distribution converts on average into the final momentum distribution of the kicked atoms. In particular, it is shown that a power-law distribution for the kicking strengths results in a L\\'evy walk in momentum space and in a power-law with the same exponent in the averaged momentum distribution. Furthermore, we investigate the stability of our predictions in the context of a realistic experiment with Bose-Einstein condensates.
Symmetries and noise in quantum walk
Chandrashekar, C. M.; Srikanth, R.; Banerjee, Subhashish
2007-08-15
We study some discrete symmetries of unbiased (Hadamard) and biased quantum walk on a line, which are shown to hold even when the quantum walker is subjected to environmental effects. The noise models considered in order to account for these effects are the phase flip, bit flip, and generalized amplitude damping channels. The numerical solutions are obtained by evolving the density matrix, but the persistence of the symmetries in the presence of noise is proved using the quantum trajectories approach. We also briefly extend these studies to quantum walk on a cycle. These investigations can be relevant to the implementation of quantum walks in various known physical systems. We discuss the implementation in the case of NMR quantum information processor and ultracold atoms.
RANDOM WALKS IN RANDOM ENVIRONMENT: WHAT A SINGLE TRAJECTORY TELLS
Enriquez, Nathanaël
RANDOM WALKS IN RANDOM ENVIRONMENT: WHAT A SINGLE TRAJECTORY TELLS OMER ADELMAN AND NATHANA with an interpretation of the process as a transition reinforced random 1 #12;2 O. ADELMAN AND N. ENRIQUEZ walk (cf
Biking, Walking to Work Can Help Shed Pounds
... nih.gov/medlineplus/news/fullstory_152451.html Biking, Walking to Work Can Help Shed Pounds U.K. ... News) -- Leaving your car at home and cycling, walking or using public transit to get to work ...
Emergence of randomness and arrow of time in quantum walks
Shikano, Yutaka
Quantum walks are powerful tools not only for constructing the quantum speedup algorithms but also for describing specific models in physical processes. Furthermore, the discrete time quantum walk has been experimentally ...
The pilot-wave dynamics of walking droplets in confinement
Harris, Daniel Martin
2015-01-01
A decade ago, Yves Couder and coworkers discovered that millimetric droplets can walk on a vibrated fluid bath, and that these walking droplets or "walkers" display several features reminiscent of quantum particles. We ...
CDC Vital Signs: More People Walk to Better Health
... the previous week. 6% Adults who walk for transportation, fun, or exercise went up 6 percent in ... More than 6 in 10 people walk for transportation or for fun, relaxation, or exercise, or for ...
A model of muscle-tendon function in human walking
Endo, Ken, Ph. D. Massachusetts Institute of Technology
2012-01-01
In order to motivate the design of legged machines that walk as humans do, this thesis investigates how leg muscles and tendons work mechanically during level-ground human walking at self-selected speeds. I hypothesize ...
2012-01-01
Background Current knowledge on the relationship between the physical environment and walking for transportation among older adults (? 65?years) is limited. Qualitative research can provide valuable information and inform further research. However, qualitative studies are scarce and fail to include neighborhood outings necessary to study participants’ experiences and perceptions while interacting with and interpreting the local social and physical environment. The current study sought to uncover the perceived environmental influences on Flemish older adults’ walking for transportation. To get detailed and context-sensitive environmental information, it used walk-along interviews. Methods Purposeful convenience sampling was used to recruit 57 older adults residing in urban or semi-urban areas. Walk-along interviews to and from a destination (e.g. a shop) located within a 15 minutes’ walk from the participants’ home were conducted. Content analysis was performed using NVivo 9 software (QSR International). An inductive approach was used to derive categories and subcategories from the data. Results Data were categorized in the following categories and subcategories: access to facilities (shops & services, public transit, connectivity), walking facilities (sidewalk quality, crossings, legibility, benches), traffic safety (busy traffic, behavior of other road users), familiarity, safety from crime (physical factors, other persons), social contacts, aesthetics (buildings, natural elements, noise & smell, openness, decay) and weather. Conclusions The findings indicate that to promote walking for transportation a neighborhood should provide good access to shops and services, well-maintained walking facilities, aesthetically appealing places, streets with little traffic and places for social interaction. In addition, the neighborhood environment should evoke feelings of familiarity and safety from crime. Future quantitative studies should investigate if (changes in) these environmental factors relate to (changes in) older adults’ walking for transportation. PMID:22780948
physics/9711006v318Nov1997 An Uncontrolled Toy That Can Walk But Cannot Stand Still
Ruina, Andy L.
- dynamic walking toys that either walk downhill or that walk on level ground when pulled by a string. Allphysics/9711006v318Nov1997 An Uncontrolled Toy That Can Walk But Cannot Stand Still Michael J a simple two-leg toy that can walk stably with no control system. It walks downhill powered only by gravity
2012-01-01
Background Given the documented physical activity disparities that exist among low-income minority communities and the increased focused on socio-ecological approaches to address physical inactivity, efforts aimed at understanding the built environment to support physical activity are needed. This community-based participatory research (CBPR) project investigates walking trails perceptions in a high minority southern community and objectively examines walking trails. The primary aim is to explore if perceived and objective audit variables predict meeting recommendations for walking and physical activity, MET/minutes/week of physical activity, and frequency of trail use. Methods A proportional sampling plan was used to survey community residents in this cross-sectional study. Previously validated instruments were pilot tested and appropriately adapted and included the short version of the validated International Physical Activity Questionnaire, trail use, and perceptions of walking trails. Walking trails were assessed using the valid and reliable Path Environmental Audit Tool which assesses four content areas including: design features, amenities, maintenance, and pedestrian safety from traffic. Analyses included Chi-square, one-way ANOVA's, multiple linear regression, and multiple logistic models. Results Numerous (n = 21) high quality walking trails were available. Across trails, there were very few indicators of incivilities and safety features rated relatively high. Among the 372 respondents, trail use significantly predicted meeting recommendations for walking and physical activity, and MET/minutes/week. While controlling for other variables, significant predictors of trail use included proximity to trails, as well as perceptions of walking trail safety, trail amenities, and neighborhood pedestrian safety. Furthermore, while controlling for education, gender, and income; for every one time per week increase in using walking trails, the odds for meeting walking recommendations increased 1.27 times, and the odds for meeting PA recommendation increased 3.54 times. Perceived and objective audit variables did not predict meeting physical activity recommendations. Conclusions To improve physical activity levels, intervention efforts are needed to maximize the use of existing trails, as well as improve residents' perceptions related to incivilities, safety, conditions of trail, and amenities of the walking trails. This study provides important insights for informing development of the CBPR walking intervention and informing local recreational and environmental policies in this southern community. PMID:22289653
Electric quantum walks with individual atoms
Maximilian Genske; Wolfgang Alt; Andreas Steffen; Albert H. Werner; Reinhard F. Werner; Dieter Meschede; Andrea Alberti
2013-02-08
We report on the experimental realization of electric quantum walks, which mimic the effect of an electric field on a charged particle in a lattice. Starting from a textbook implementation of discrete-time quantum walks, we introduce an extra operation in each step to implement the effect of the field. The recorded dynamics of such a quantum particle exhibits features closely related to Bloch oscillations and interband tunneling. In particular, we explore the regime of strong fields, demonstrating contrasting quantum behaviors: quantum resonances vs. dynamical localization depending on whether the accumulated Bloch phase is a rational or irrational fraction of 2\\pi.
Quantum Random Walks with General Particle States
NASA Astrophysics Data System (ADS)
Belton, Alexander C. R.
2014-06-01
A convergence theorem is obtained for quantum random walks with particles in an arbitrary normal state. This unifies and extends previous work on repeated-interactions models, including that of Attal and Pautrat (Ann Henri Poincaré 7:59-104 2006) and Belton (J Lond Math Soc 81:412-434, 2010; Commun Math Phys 300:317-329, 2010). When the random-walk generator acts by ampliation and either multiplication or conjugation by a unitary operator, it is shown that the quantum stochastic cocycle which arises in the limit is driven by a unitary process.
Modified discrete random walk with absorption
Theo van Uem
2009-03-02
We obtain expected number of arrivals, probability of arrival, absorption probabilities and expected time before absorption for a modified discrete random walk on the (sub)set of integers. In a [pqrs] random walk the particle can move one step forward or backward, stay for a moment in the same state or it can be absorbed immediately in the current state. M[pqrs] is a modified version, where probabilities on both sides of a multiple function barrier M are of different [pqrs] type.
Total progeny in killed branching random walk
Addario-Berry, Louigi
2009-01-01
We consider a branching random walk for which the maximum position of a particle in the n'th generation, M_n, has zero speed on the linear scale: M_n/n --> 0 as n --> infinity. We further remove ("kill") any particle whose displacement is negative, together with its entire descendence. The size $Z$ of the set of un-killed particles is almost surely finite. In this paper, we confirm a conjecture of Aldous that Exp[Z] < infinity while Exp[Z log Z]=infinity. The proofs rely on precise large deviations estimates and ballot theorem-style results for the sample paths of random walks.
Fifteen-minute consultation: A child with toe walking.
Sivaramakrishnan, Shobha; Seal, Arnab
2015-10-01
Toe walking is a common developmental phenomenon in young children. It is usually benign and self-limiting. Toe walking can be a presenting sign of some serious underlying disorders and idiopathic toe walking is a diagnosis of exclusion. Persistent toe walking can lead to limited ankle dorsiflexion which may cause functional problems. Specific interventions depend on underlying cause and may range from verbal reinforcement to serial casting and surgery. PMID:25855215
Continuous-time quantum walks on star graphs
S. Salimi
2009-04-25
In this paper, we investigate continuous-time quantum walk on star graphs. It is shown that quantum central limit theorem for a continuous-time quantum walk on star graphs for $N$-fold star power graph, which are invariant under the quantum component of adjacency matrix, converges to continuous-time quantum walk on $K_2$ graphs (Complete graph with two vertices) and the probability of observing walk tends to the uniform distribution.
Continuous-time quantum walks on star graphs
Salimi, S. [Department of Physics, University of Kurdistan, P.O. Box 66177-15175, Sanandaj (Iran, Islamic Republic of)], E-mail: shsalimi@uok.ac.ir
2009-06-15
In this paper, we investigate continuous-time quantum walk on star graphs. It is shown that quantum central limit theorem for a continuous-time quantum walk on star graphs for N-fold star power graph, which are invariant under the quantum component of adjacency matrix, converges to continuous-time quantum walk on K{sub 2} graphs (complete graph with two vertices) and the probability of observing walk tends to the uniform distribution.
Emergence of Randomness and Arrow of Time in Quantum Walks
Yutaka Shikano; Kota Chisaki; Etsuo Segawa; Norio Konno
2010-06-28
Quantum walks are powerful tools not only to construct the quantum speedup algorithms but also to describe specific models in physical processes. Furthermore, the discrete time quantum walk has been experimentally realized in various setups. We apply the concept of the quantum walk to the problems in quantum foundations. We show that randomness and the arrow of time in the quantum walk gradually emerge by periodic projective measurements from the mathematically obtained limit distribution under the time scale transformation.
Emergence of randomness and arrow of time in quantum walks
Shikano, Yutaka; Chisaki, Kota; Konno, Norio; Segawa, Etsuo
2010-06-15
Quantum walks are powerful tools not only for constructing the quantum speedup algorithms but also for describing specific models in physical processes. Furthermore, the discrete time quantum walk has been experimentally realized in various setups. We apply the concept of the quantum walk to the problems in quantum foundations. We show that randomness and the arrow of time in the quantum walk gradually emerge by periodic projective measurements from the mathematically obtained limit distribution under the time-scale transformation.
Emergence of randomness and arrow of time in quantum walks
NASA Astrophysics Data System (ADS)
Shikano, Yutaka; Chisaki, Kota; Segawa, Etsuo; Konno, Norio
2010-06-01
Quantum walks are powerful tools not only for constructing the quantum speedup algorithms but also for describing specific models in physical processes. Furthermore, the discrete time quantum walk has been experimentally realized in various setups. We apply the concept of the quantum walk to the problems in quantum foundations. We show that randomness and the arrow of time in the quantum walk gradually emerge by periodic projective measurements from the mathematically obtained limit distribution under the time-scale transformation.
Quantum walk on the line as an interference phenomenon
Knight, Peter L.; Roldan, Eugenio; Sipe, J. E. [Optics Section, Blackett Laboratory, Imperial College London, London SW7 2AZ, (United Kingdom)
2003-08-01
We show that the coined quantum walk on a line can be understood as an interference phenomenon, can be classically implemented, and indeed already has been. The walk is essentially two independent walks associated with the different coin sides, coupled only at initiation. There is a simple analogy between the evolution of walker positions and the propagation of light in a dispersive optical fiber.
Convergence of coined quantum walks on Rd Alex D. Gottlieb
Janson, Svante
Convergence of coined quantum walks on Rd Alex D. Gottlieb , Svante Janson , and Petra F. Scudo June 7, 2004; corrected October 5, 2004 Abstract Coined quantum walks may be interpreted as the motion conditional on the spin state. Coined quantum walks on Zd can be treated as special cases of coined quantum
Convergence of coined quantum walks on Rd Alex D. Gottlieb
Janson, Svante
Convergence of coined quantum walks on Rd Alex D. Gottlieb , Svante Janson , and Petra F. Scudo June 7, 2004; revised October 7, 2004 Abstract Coined quantum walks may be interpreted as the motion conditional on the spin state. Coined quantum walks on Zd can be treated as special cases of coined quantum
Accumulating Brisk Walking for Fitness, Cardiovascular Risk, and Psychological Health.
ERIC Educational Resources Information Center
Murphy, Marie; Nevill, Alan; Neville, Charlotte; Biddle, Stuart; Hardman, Adrianne
2002-01-01
Compared the effects of different patterns of regular brisk walking on fitness, cardiovascular disease risk factors, and psychological well-being in previously sedentary adults. Data on adults who completed either short-bout or long-bout walking programs found that three short bouts of brisk walking accumulated throughout the day were as effective…
Biased random walk on critical Galton-Watson trees
RIMS-1744 Biased random walk on critical Galton-Watson trees conditioned to survive By David A KYOTO UNIVERSITY, Kyoto, Japan #12;Biased random walk on critical Galton-Watson trees conditioned walk on a critical Galton-Watson tree conditioned to survive, and confirm that this model with trapping
[Type text] Walking directions from the bus and train
Wiesner, Karoline
[Type text] Walking directions from the bus and train stations Bristol Temple Meads Train Station is much closer to Temple Meads station. It takes 30 to 40 minutes to walk from Temple Meads to the University and the walk involves an uphill climb. Leave the station taking the right-hand pavement past bus
A Natural Walking Monitor for Pulmonary Patients Using Mobile Phones.
Juen, Joshua; Cheng, Qian; Schatz, Bruce
2015-07-01
Mobile devices have the potential to continuously monitor health by collecting movement data including walking speed during natural walking. Natural walking is walking without artificial speed constraints present in both treadmill and nurse-assisted walking. Fitness trackers have become popular which record steps taken and distance, typically using a fixed stride length. While useful for everyday purposes, medical monitoring requires precise accuracy and testing on real patients with a scientifically valid measure. Walking speed is closely linked to morbidity in patients and widely used for medical assessment via measured walking. The 6-min walk test (6MWT) is a standard assessment for chronic obstructive pulmonary disease and congestive heart failure. Current generation smartphone hardware contains similar sensor chips as in medical devices and popular fitness devices. We developed a middleware software, MoveSense, which runs on standalone smartphones while providing comparable readings to medical accelerometers. We evaluate six machine learning methods to obtain gait speed during natural walking training models to predict natural walking speed and distance during a 6MWT with 28 pulmonary patients and ten subjects without pulmonary condition. We also compare our model's accuracy to popular fitness devices. Our universally trained support vector machine models produce 6MWT distance with 3.23% error during a controlled 6MWT and 11.2% during natural free walking. Furthermore, our model attains 7.9% error when tested on five subjects for distance estimation compared to the 50-400% error seen in fitness devices during natural walking. PMID:25935052
Walking Robotics The Cornell Ranger Fall 2006 Semester Report
Ruina, Andy L.
Walking Robotics The Cornell Ranger Fall 2006 Semester Report Alexander Gates Sophomore, Cornell in the Ranger. Using these components, the Cornell Ranger recently set a distance record for walking robots, walking for a little over a kilometer. #12;3 Introduction One of the key traits that distinguish Homo
Correct Software Synthesis for Stable Speed-Controlled Robotic Walking
Ames, Aaron
Correct Software Synthesis for Stable Speed-Controlled Robotic Walking Neil Dantam, Ayonga Hereid-3123, USA Abstract--We present a software synthesis method for speed- controlled robot walking based parameters for fixed speed walking and for transitions between fixed speeds, guaranteeing dynamic stability
Synthesis of Controllers for Stylized Planar Bipedal Walking
Panne, M. van de
Synthesis of Controllers for Stylized Planar Bipedal Walking Dana Sharon, and Michiel van de Panne,van}@cs.ubc.ca Abstract-- We present a method for computing controllers for stable planar-biped walking gaits that follow of a simulated motion from a desired target motion. We demonstrate simulated bipedal walks having user
A Proposal for Data Collection: Establishing Pedestrian Walking Speeds
Bertini, Robert L.
A Proposal for Data Collection: Establishing Pedestrian Walking Speeds Submitted to: Karen Aspelin on Uniform Traffic Control Devices (MUTCD) currently recommends that a normal pedestrian walking speed of 4 been a select number of studies on pedestrian walking speeds in the past (see Laplante and Kaeser, ITE
Eye Movements of Patients with Tunnel Vision While Walking
Peli, Eli
Eye Movements of Patients with Tunnel Vision While Walking Fernando Vargas-Marti´n1,2 and Eli Peli2 relative to the head in patients walking in real environments. This information should help to define° of visual field and in three normally sighted people, each walking in varied environments for more than 30
Integer Addition and Subtraction: Walking the Number Line (2)
NSDL National Science Digital Library
EDC in Maine
2012-01-01
This Java applet, an adaption of "Integer Addition and Subtraction: Walking the Number Line" (cataloged separately) models the addition and subtraction of integers of example expressions by walking a character along a number line. A slider changes the example expression and the check boxes show or can hide the character's walking trail, hints and solutions for the example expressions.
Dynamic Walking and Running of the Quadruped Using Neural Oscillator
Kimura, Hiroshi
Dynamic Walking and Running of the Quadruped Using by Brooks[6] in h* *is proposal of the behavior- quadruped robot to walk dynamically on irregularbter of animals are con- model. For dynamic walking on irregular terrain,twerolled by internal nervous s* *ystems
Walking Technicolor & AdS/CFT Daniel Elander
Walking Technicolor & AdS/CFT Daniel Elander Tata Institute of Fundamental Research April 10, 2012 Daniel Elander Walking Technicolor & AdS/CFT #12;Introduction Electro-Weak Symmetry Breaking (EWSB µ - ig 1 2 Bµ EWSB due to non-zero VEV: = 1 2 0 v Daniel Elander Walking Technicolor & AdS/CFT #12
Walking Box Ranch An endeavor, an economic pursuit, a retreat.
Hemmers, Oliver
Walking Box Ranch An endeavor, an economic pursuit, a retreat. Clockwise from far left: Silent lm by Viceroy Gold Corporation; a sunset view of the New York Mountains from Walking Box Ranch. ith thousands of years of human history, the Walking Box Ranch site provides a glimpse of what nearly every human culture
Help Advance Research and Education to Promote Walking and Bicycling
Bertini, Robert L.
Help Advance Research and Education to Promote Walking and Bicycling The Initiative for Bicycle and Pedestrian Innovation (IBPI) was founded to promote change that makes it easier and safer to walk and bicycle and policy-makers can use to build· communities where walking and biking is a safe, convenient
Biped Walking Pattern Generator allowing Auxiliary ZMP Control
Treuille, Adrien
Biped Walking Pattern Generator allowing Auxiliary ZMP Control Shuuji KAJITA, Mitsuharu MORISAWA-kanehiro,k-fujiwara,hiro.hirukawa}@aist.go.jp Abstract-- A biped walking pattern generator which allows an additional ZMP control (auxiliary ZMP of the reference ZMP. As an application of the proposed method, a walking control on uneven terrain is simulated
Dynamic Walking and Running of the Quadruped Using Neural Oscillator
Kimura, Hiroshi
Dynamic Walking and Running of the Quadruped Using Neural Oscillator Hiroshi Kimura, Kazuaki 1828585, JAPAN Abstract In the present study we attempt to induce a quadruped robot to walk walking on irregular terrain, we employ a control system involving a neural oscillator network, a stretch
Walking and the Preservation of Cognitive Function in Older Populations
ERIC Educational Resources Information Center
Prohaska, Thomas R.; Eisenstein, Amy R.; Satariano, William A.; Hunter, Rebecca; Bayles, Constance M.; Kurtovich, Elaine; Kealey, Melissa; Ivey, Susan L.
2009-01-01
Purpose: This cross-sectional study takes a unique look at the association between patterns of walking and cognitive functioning by examining whether older adults with mild cognitive impairment differ in terms of the community settings where they walk and the frequency, intensity, or duration of walking. Design and Methods: The sample was based on…
Compliant leg behaviour explains basic dynamics of walking and running
Geyer, Hartmut
Compliant leg behaviour explains basic dynamics of walking and running Hartmut Geyer1,*, Andre in walking and rebounding on compliant legs in running. However, while rebounding legs well explain the stance dynamics of running, stiff legs cannot reproduce that of walking. With a simple bipedal spring
Quantum walks in waveguide-based optical quantum device
NASA Astrophysics Data System (ADS)
Wu, Nan; Hu, Haixing; Xu, Ping; Song, Fangmin; Li, Xiangdong
2014-05-01
We study multi-dimension quantum walks and its dimension reduction model. By using an waveguide-based optical quantum device, we demonstrate the quantum-walk in searching algorithms such as 2-D glued tree and 3-D hypercube graph. We discuss that the use of waveguide-based device is a good candidate to implement the quantum walks.
The Not-so-Random Drunkard's Walk
ERIC Educational Resources Information Center
Ehrhardt, George
2013-01-01
This dataset contains the results of a quasi-experiment, testing Karl Pearson's "drunkard's walk" analogy for an abstract random walk. Inspired by the alternate hypothesis that drunkards stumble to the side of their dominant hand, it includes data on intoxicated test subjects walking a 10' line. Variables include: the…
NON-PERTURBATIVE APPROACH TO RANDOM WALK IN MARKOVIAN ENVIRONMENT.
Liverani, Carlangelo
NON-PERTURBATIVE APPROACH TO RANDOM WALK IN MARKOVIAN ENVIRONMENT. DMITRY DOLGOPYAT AND CARLANGELO LIVERANI Abstract. We prove the CLT for a random walk in a dynamical environment where the states of the environment at different sites are independent Markov chains. 1. Introduction The study of random walk
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-15
...the Public Comment Period for Walk-In Coolers and Walk-in Freezers AGENCY: Office...technical support document for walk-in coolers and freezers and a public meeting on May...technical support document for walk-in coolers and walk-in freezers is to be...
Searching via walking: How to find a marked clique of a complete graph using quantum walks
Hillery, Mark; Reitzner, Daniel; Buzek, Vladimir
2010-06-15
We show how a quantum walk can be used to find a marked edge or a marked complete subgraph of a complete graph. We employ a version of a quantum walk, the scattering walk, which lends itself to experimental implementation. The edges are marked by adding elements to them that impart a specific phase shift to the particle as it enters or leaves the edge. If the complete graph has N vertices and the subgraph has K vertices, the particle becomes localized on the subgraph in O(N/K) steps. This leads to a quantum search that is quadratically faster than a corresponding classical search. We show how to implement the quantum walk using a quantum circuit and a quantum oracle, which allows us to specify the resources needed for a quantitative comparison of the efficiency of classical and quantum searches--the number of oracle calls.
in persons with post-stroke hemiparesis A.L. Hall a , C.L. Peterson a , S.A. Kautz b,c,d , R.R. Neptune a Gait Muscle function Background: Persons with post-stroke hemiparesis usually walk slowly and asymmetrically. Stroke severity and functional walking status are commonly predicted by post-stroke walking speed
799 The mechanisms that govern the voluntary transition in human gait from walking to running as walking speed increases have received much attention from both experimental and theoretical perspectives studies have suggested that the walk-to-run transition is closely linked to the minimization of metabolic
Srinivasan, Manoj
Walking, running, and resting under time, distance, and average speed constraints: Optimality of walk-run-rest mixtures Leroy L. Long III and Manoj Srinivasan Mechanical and Aerospace Engineering to running beyond a characteristic transition speed. Here, we study human choice between walking and running
ERIC Educational Resources Information Center
Focht, Brian C.
2009-01-01
The purpose of this study was to compare the effect of brief walks completed in outdoor and laboratory environments on affective responses, enjoyment, and intention to walk for exercise. Thirty-five active young women (M age = 22.14 years, SD = 1.73) walked for 10 min at a self-selected intensity in outdoor and laboratory environments. Affective…
Sung-Kyun Kim; Seokmin Hong; Doik Kim
2009-01-01
Teleoperation of humanoid robots, which is one of good methods of humanoid utilization, has difficulties in locomotion with self-balancing. In this paper, we propose a framework of walking imitation between human and a humanoid robot. Using inertial measurement unit (IMU), human's walking motions are recognized, and used as humanoid robot control inputs for on-line walking imitation. Appropriate IMU feature data
Pellegrini, Barbara; Peyré-Tartaruga, Leonardo Alexandre; Zoppirolli, Chiara; Bortolan, Lorenzo; Bacchi, Elisabetta; Figard-Fabre, Hélène; Schena, Federico
2015-01-01
Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill. PMID:26418339
Walk Test Used to Monitor the Performance in the Health-Directed Nordic Walking
ERIC Educational Resources Information Center
Kamien, Dorota
2008-01-01
Study aim: To assess the performance of subjects engaged in health-directed Nordic Walking training (with poles) and subjected to 2-km walk test (no poles). Material and methods: A total of 72 subjects, including 8 men and 32 women aged 23-73 years and 32 female students aged 19-25 years participated in the study. They were subjected twice to 2-km…
Random Walk Method for Potential Problems
NASA Technical Reports Server (NTRS)
Krishnamurthy, T.; Raju, I. S.
2002-01-01
A local Random Walk Method (RWM) for potential problems governed by Lapalace's and Paragon's equations is developed for two- and three-dimensional problems. The RWM is implemented and demonstrated in a multiprocessor parallel environment on a Beowulf cluster of computers. A speed gain of 16 is achieved as the number of processors is increased from 1 to 23.
Grover Search with Lackadaisical Quantum Walks
Thomas G. Wong
2015-05-11
The lazy random walk, where the walker has some probability of staying put, is a useful tool in classical algorithms. We propose a quantum analogue, the lackadaisical quantum walk, where each vertex is given $l$ self-loops, and we investigate its effects on Grover's algorithm when formulated as search for a marked vertex on the complete graph of $N$ vertices. For the discrete-time quantum walk using the phase flip coin, adding a self-loop to each vertex boosts the success probability from 1/2 to 1. Additional self-loops, however, decrease the success probability. Using instead the Ambainis, Kempe, and Rivosh (2005) coin, adding self-loops simply slows down the search. These coins also differ in that the first is faster than classical when $l$ scales less than $N$, while the second requires that $l$ scale less than $N^2$. Finally, continuous-time quantum walks differ from both of these discrete-time examples---the self-loops make no difference at all. These behaviors generalize to multiple marked vertices.
Kinesin: walking, crawling or sliding along?
Yildiz, Ahmet
Kinesin: walking, crawling or sliding along? Ahmet Yildiz and Paul R. Selvin Department of Physics, University of Illinois, Urbana-Champaign, IL 61801, USA Kinesins are microtubule-based motor proteins. Recently, con- ventional kinesin, which was the first-identified member of the family, has been shown
The walk and jump of Equisetum spores.
Marmottant, Philippe; Ponomarenko, Alexandre; Bienaimé, Diane
2013-11-01
Equisetum plants (horsetails) reproduce by producing tiny spherical spores that are typically 50 µm in diameter. The spores have four elaters, which are flexible ribbon-like appendages that are initially wrapped around the main spore body and that deploy upon drying or fold back in humid air. If elaters are believed to help dispersal, the exact mechanism for spore motion remains unclear in the literature. In this manuscript, we present observations of the 'walks' and 'jumps' of Equisetum spores, which are novel types of spore locomotion mechanisms compared to the ones of other spores. Walks are driven by humidity cycles, each cycle inducing a small step in a random direction. The dispersal range from the walk is limited, but the walk provides key steps to either exit the sporangium or to reorient and refold. Jumps occur when the spores suddenly thrust themselves after being tightly folded. They result in a very efficient dispersal: even spores jumping from the ground can catch the wind again, whereas non-jumping spores stay on the ground. The understanding of these movements, which are solely driven by humidity variations, conveys biomimetic inspiration for a new class of self-propelled objects. PMID:24026816
Di, TG; Hillery, M.; Zubairy, M. Suhail
2004-01-01
We discuss a possible experimental scheme for the implementation of a quantum walk. The scheme is based on the passage of an atom inside a high-Q cavity. The chirality is characterized by the atomic states and the displacement is characterized...
Elementary Education: Elementary Students Simulate Moon Walk.
ERIC Educational Resources Information Center
Aviation/Space, 1980
1980-01-01
Describes the project of a fourth- and fifth-grade class in simulating a moon walk. Teams consisted of the astronauts, the life support team, the flight program team, the communications team, the scientific team, and the construction team. Their visit to the Marshall Space Flight Center is also described. (SA)
Random walk hypothesis in exchange rate reconsidered
Hsin-Min Lu; Chia-Shang J. Chu
2006-01-01
An econometric model for exchange rate based on the behavior of dynamic international asset allocation is considered. The capital movement intensity index is constructed from the adjustment of a fully hedged international portfolio. Including this index as an additional explanatory variable helps to explain the fluctuation of the exchange rate and predict better than the competing random walk model. Supporting
Random walk centrality for temporal networks
NASA Astrophysics Data System (ADS)
Rocha, Luis E. C.; Masuda, Naoki
2014-06-01
Nodes can be ranked according to their relative importance within a network. Ranking algorithms based on random walks are particularly useful because they connect topological and diffusive properties of the network. Previous methods based on random walks, for example the PageRank, have focused on static structures. However, several realistic networks are indeed dynamic, meaning that their structure changes in time. In this paper, we propose a centrality measure for temporal networks based on random walks under periodic boundary conditions that we call TempoRank. It is known that, in static networks, the stationary density of the random walk is proportional to the degree or the strength of a node. In contrast, we find that, in temporal networks, the stationary density is proportional to the in-strength of the so-called effective network, a weighted and directed network explicitly constructed from the original sequence of transition matrices. The stationary density also depends on the sojourn probability q, which regulates the tendency of the walker to stay in the node, and on the temporal resolution of the data. We apply our method to human interaction networks and show that although it is important for a node to be connected to another node with many random walkers (one of the principles of the PageRank) at the right moment, this effect is negligible in practice when the time order of link activation is included.
Communities, Random Walks, and Social Sybil Defense
Alvisi, Lorenzo
Communities, Random Walks, and Social Sybil Defense Lorenzo Alvisi , Allen Clement , Alessandro to distributed systems and online social networks. The goal of sybil defense is to accurately identify sybil identities. This paper surveys the evolution of sybil defense protocols that leverage the structural
Idealized walking and running gaits minimize work
Ruina, Andy L.
previously using numerical optimization of a minimal mathematical model of a biped (Srinivasan and Ruina). To explore this conjecture, we pre- viously formulated a simple mathematical model of a bipedal animal, "inverted pendulum walking" and "impulsive running", do indeed minimize the amount of positive work required
Idealized walking and running gaits minimize work
Srinivasan, Manoj
this possibility previously using numerical optimization of a minimal mathematical model of a biped. We had found a simple mathematical model of a bipedal animal consisting of a point mass upper body and two massless legs that, for a given step-length, the two classical descriptions of walking and running, `inverted
Healthy Living Initiative: Running/Walking Club
ERIC Educational Resources Information Center
Stylianou, Michalis; Kulinna, Pamela Hodges; Kloeppel, Tiffany
2014-01-01
This study was grounded in the public health literature and the call for schools to serve as physical activity intervention sites. Its purpose was twofold: (a) to examine the daily distance covered by students in a before-school running/walking club throughout 1 school year and (b) to gain insights on the teachers perspectives of the club.…
Moments of coinless quantum walks on lattices
NASA Astrophysics Data System (ADS)
Santos, Raqueline Azevedo Medeiros; Portugal, Renato; Boettcher, Stefan
2015-06-01
The properties of the coinless quantum-walk model have not been as thoroughly analyzed as those of the coined model. Both evolve in discrete time steps, but the former uses a smaller Hilbert space, which is spanned merely by the site basis. Besides, the evolution operator can be obtained using a process of lattice tessellation, which is very appealing. The moments of the probability distribution play an important role in the context of quantum walks. The ballistic behavior of the mean square displacement indicates that quantum-walk-based algorithms are faster than random-walk-based ones. In this paper, we obtain analytical expressions for the moments of the coinless model on d-dimensional lattices by employing the methods of Fourier transforms and generating functions. The mean square displacement for large times is explicitly calculated for the one- and two-dimensional lattices, and using optimization methods, the parameter values that give the largest spread are calculated and compared with the equivalent ones of the coined model. Although we have employed asymptotic methods, our approximations are accurate even for small numbers of time steps.
Paleoanthropology: When hobbits (slowly) walked the earth.
Culotta, Elizabeth
2008-04-25
At the recent American Association of Physical Anthropology meetings, a researcher described the foot bones of an 18,000-year-old Indonesian skeleton known as the "hobbit." The tiny hominin would not have walked like we do, he said, and may offer "a window into a primitive bipedal foot." PMID:18436747
3. Introduction 16. Short Random Walks
Borwein, Jonathan
faa faaas Laureate Professor & Director of CARMA, Univ. of Newcastle this talk: http://carma.newcastle.edu.au/jon/handbook.pdf://carma.newcastle.edu.au/jon/logsin3.pdf J.M. Borwein Mahler Measures #12;3. Introduction 16. Short Random Walks 40. Multiple Mahler, DC Objectives. The conference will provide a forum for the exchange of expertise, experience
Computer Science Advising Walk In Hours
Salvaggio, Carl
Computer Science Advising Walk In Hours Computer Science Student Services Office, Golisano Hall Day/Time Undergraduate A F Rebecca O'Connor Tuesday 1pm-2pm & Wednesday 2pm-3pm Undergraduate G M Mina Pulcini Wednesday & Thursday 1pm-2pm Undergraduate N Z Christina Rohr Tuesday & Wednesday 2pm-3
THE GEORGE WASHINGTON UNIVERSITY WALKING TOUR
Vertes, Akos
THE GEORGE WASHINGTON UNIVERSITY MOUNT VERNON CAMPUS WALKING TOUR #12;The tour begins as soon and Campus Life Center, featuring a full-service dining room, a late-night grill window, seating Campus. This campus offers GW students academic programs and student life opportunities in a traditional
Walking-Beam Solar-Cell Conveyor
NASA Technical Reports Server (NTRS)
Feder, H.; Frasch, W.
1982-01-01
Microprocessor-controlled walking-beam conveyor moves cells between work stations in automated assembly line. Conveyor has arm at each work station. In unison arms pick up all solar cells and advance them one station; then beam retracks to be in position for next step. Microprocessor sets beam stroke, speed, and position.
Analyzing and recognizing walking figures in XYT
Sourabh A. Niyogi; Edward H. Adelson
1994-01-01
We describe a novel algorithm for gait analysis. A person walking frontoparallel to the image plane generates a characteristic “braided” pattern in a spatiotemporal (XYT) volume. Our algorithm detects this pattern, and fits it with a set of spatiotemporal snakes. The snakes can be used to find the bounding contours of the walker. The contours vary over time in a
Random Walks and Percolation on Trees
Russell Lyons
1990-01-01
There is a way to define an average number of branches per vertex for an arbitrary infinite locally finite tree. It equals the exponential of the Hausdorff dimension of the boundary in an appropriate metric. Its importance for probabilistic processes on a tree is shown in several ways, including random walk and percolation, where it provides points of phase transition.
Walking Tracks Tracks Location Track Information
Rock, Chris
Walking Tracks Tracks Location Track Information Texas Tech Campus Maps available at www.depts.ttu.edu/recsports Berry Park 36th Street & Cedar Avenue .42 Mile Concrete Track Carlisle Park 28th Street & Avenue X .28 Mile Concrete Track Chatman Park E. 29th Street & Juniper Avenue .24 Mile Concrete Track Conquistador
Moments of Coinless Quantum Walks on Lattices
Raqueline A. M. Santos; Renato Portugal; Stefan Boettcher
2015-02-23
The properties of the coinless quantum walk model have not been as thoroughly analyzed as those of the coined model. Both evolve in discrete time steps but the former uses a smaller Hilbert space, which is spanned merely by the site basis. Besides, the evolution operator can be obtained using a process of lattice tessellation, which is very appealing. The moments of the probability distribution play an important role in the context of quantum walks. The ballistic behavior of the mean square displacement indicates that quantum-walk-based algorithms are faster than random-walk-based ones. In this paper, we obtain analytical expressions for the moments of the coinless model on $d$-dimensional lattices. The mean square displacement for large times is explicitly calculated for the one- and two-dimensional lattices and, using optimization methods, the parameter values that give the largest spread are calculated and compared with the equivalent ones of the coined model. Although we have employed asymptotic methods, our approximations are accurate even for small numbers of time steps.
Exploring Space and Place with Walking Interviews
ERIC Educational Resources Information Center
Jones, Phil; Bunce, Griff; Evans, James; Gibbs, Hannah; Hein, Jane Ricketts
2008-01-01
This article explores the use of walking interviews as a research method. In spite of a wave of interest in methods which take interviewing out of the "safe," stationary environment, there has been limited work critically examining the techniques for undertaking such work. Curiously for a method which takes an explicitly spatial approach, few…
Multifractal analysis of DNA walks and trails.
Rosas, Alexandre; Nogueira, Edvaldo; Fontanari, José F
2002-12-01
The characterization of the long-range order and fractal properties of DNA sequences has proved a difficult though rewarding task mainly due to the mosaic character of DNA consisting of many interwoven patches of various lengths with different nucleotide constitutions. We apply here a recently proposed generalization of the detrended fluctuation analysis method to show that the DNA walk construction, in which the DNA sequence is viewed as a time series, exhibits a monofractal structure regardless of the existence of local trends in the series. In addition, we point out that the monofractal structure of the DNA walks carries over to an apparently alternative graphical construction given by the projection of the DNA walk into the d spatial coordinates, termed DNA trails. In particular, we calculate the fractal dimension D(t) of the DNA trails using a well-known result of fractal theory linking D(t) to the Hurst exponent H of the corresponding DNA walk. Comparison with estimates obtained by the standard box-counting method allows the evaluation of both finite-length and local trends effects. PMID:12513317
The Physics of a Walking Robot
ERIC Educational Resources Information Center
Guemez, J.; Fiolhais, M.
2013-01-01
The physics of walking is explored, using a toy as a concrete example and a "toy model" applied to it. Besides using Newton's second law, the problem is also discussed from the thermodynamical perspective. Once the steady state (constant velocity) is achieved, we show that the internal energy of the toy is dissipated as heat in the…
The true reinforced random walk with bias
NASA Astrophysics Data System (ADS)
Agliari, E.; Burioni, R.; Uguzzoni, G.
2012-06-01
We consider a self-attracting random walk in dimension d = 1, in the presence of a field of strength s, which biases the walker toward a target site. We focus on the dynamic case (the true reinforced random walk), where memory effects are implemented at each time step, in contrast with the static case, where memory effects are accounted for globally. We analyze in details the asymptotic long-time behavior of the walker through the main statistical quantities (e.g. distinct sites visited and end-to-end distance) and we discuss a possible mapping between such a dynamic self-attracting model and the trapping problem for a simple random walk, in analogy to the static model. Moreover, we find that, for any s > 0, the random walk behavior switches to ballistic and that field effects always prevail over memory effects without any singularity, already in d = 1 this is in contrast with the behavior observed in the static model.
The Two-Dimensional Random Walk
NSDL National Science Digital Library
McGath, Gary
This is the description and instructions for the Two-Dimensional Random Walk applet. This applet, presented by Boston University's Center for Polymer Studies, relates random coin-flipping to random motion but in more than one direction (dimension). It covers mean squared distance in the discussion. Overall, this is a nice interactive resource for a statistics classroom.
Clairvoyant scheduling of random walks Peter Gacs
Gacs, Peter
the two 1 #12;2 0 1 2 3 4 Y : WAIT X : GO Figure 1: The clairvoyant demon problem. X,Y are "tokens" performing independent ran- dom walks on the same graph: here the complete graph K5. A "demon" decides every the clairvoyant demon problem, arose first in distributed computing. The original problem was to find a leader
Moments of coinless quantum walks on lattices
NASA Astrophysics Data System (ADS)
Santos, Raqueline Azevedo Medeiros; Portugal, Renato; Boettcher, Stefan
2015-09-01
The properties of the coinless quantum-walk model have not been as thoroughly analyzed as those of the coined model. Both evolve in discrete time steps, but the former uses a smaller Hilbert space, which is spanned merely by the site basis. Besides, the evolution operator can be obtained using a process of lattice tessellation, which is very appealing. The moments of the probability distribution play an important role in the context of quantum walks. The ballistic behavior of the mean square displacement indicates that quantum-walk-based algorithms are faster than random-walk-based ones. In this paper, we obtain analytical expressions for the moments of the coinless model on d-dimensional lattices by employing the methods of Fourier transforms and generating functions. The mean square displacement for large times is explicitly calculated for the one- and two-dimensional lattices, and using optimization methods, the parameter values that give the largest spread are calculated and compared with the equivalent ones of the coined model. Although we have employed asymptotic methods, our approximations are accurate even for small numbers of time steps.
Measurements in the Levy quantum walk
Romanelli, A.
2007-11-15
We study the quantum walk subjected to measurements with a Levy waiting-time distribution. We find that the system has a sub-ballistic behavior instead of a diffusive one. We obtain an analytical expression for the exponent of the power law of the variance as a function of the characteristic parameter of the Levy distribution.
Myths about the Country Walk Case
ERIC Educational Resources Information Center
Cheit, Ross E.; Mervis, David
2007-01-01
The Country Walk case in Dade County, Florida was long considered a model for how to prosecute a multi-victim child sexual abuse case involving young children. In the past 10 years, however, a contrary view has emerged that the case was tainted by improper interviewing and was likely a false conviction. This is the first scholarly effort to assess…
ERIC Educational Resources Information Center
Moss, Connie M.; Brookhart, Susan M.
2013-01-01
Traditionally, principals have used walk-throughs to determine whether teachers are implementing strategies that the principal believes define good teaching. In this model, the principal is the expert, and the teacher is the learner. Connie M. Moss and Susan M. Brookhart believe that this approach can cause the principal to disregard the classroom…
Heisenberg Model, Bethe Ansatz, and Random Walks
Ng, Lenny
Heisenberg Model, Bethe Ansatz, and Random Walks Lenhard L. Ng Senior Honors Thesis Harvard) 493-7613 #12;Contents 1 Introduction 2 2 Physical background 4 2.1 The Heisenberg model of magnetism . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Mathematical formulation of the one-dimensional Heisenberg model H . . . . 5 2.3 Physical
Walking to School: Taking Research to Practice
ERIC Educational Resources Information Center
Heelan, Kate A.; Unruh, Scott A.; Combs, H. Jason; Donnelly, Joseph E.; Sutton, Sarah; Abbey, Bryce M.
2008-01-01
This article describes the results of a study that helped determine common barriers to active commuting to and from school, as well as the results of a Walking School Bus program that was implemented at two neighborhood elementary schools in Nebraska. While parental perceived barriers to active commuting may influence the travel choices of…
Take a Hike!: A Family Forest Walk
NSDL National Science Digital Library
Smithsonian National Zoological Park
2012-06-26
In this family or group inquiry activity, learners use their senses to explore a local forest or woodland. Learners can look for decomposers and fungi, investigate flowers and pollination, and practice observation skills while looking for signs of plant and animal life interaction. Learners will sketch their findings in a nature journal and then share their observations after the forest walk.
Comparison of elliptical training, stationary cycling, treadmill walking and overground walking
Prosser, Laura A.; Stanley, Christopher J.; Norman, Tracy L.; Park, Hyung S.; Damiano, Diane L.
2012-01-01
The most common functional motor goal of lower extremity rehabilitation is to improve walking ability. For reasons of feasibility, safety or intensity, devices are frequently used to facilitate or augment gait training. The objective of this study was to compare the muscle activity patterns of the quadriceps and hamstring muscles during four conditions: overground walking, treadmill walking, stationary cycling, and elliptical training. Ten healthy adults (6 male, 4 female; mean age 22.7 ± 2.9 yrs, range 20–29) participated. Surface electromyographic data were recorded from the rectus femoris and semitendinosus. Linear envelope curves were generated and time normalized from 0–100% cycle. The mean plus three standard deviations from a static trial was used as the threshold for muscle activity. Repeated measures analysis of variance procedures were used to detect differences between conditions. Elliptical training demonstrated greater quadriceps activity and greater quadriceps/hamstrings coactivation than all other conditions. Consistent with previous work, treadmill walking demonstrated greater quadriceps activity than overground walking. Minimal differences in hamstring activation were observed between conditions, limited to lower peak activity during cycling compared to treadmill walking. These results provide normative values for quadriceps and hamstring activation for different locomotor training methods and may assist in selecting the most appropriate training device for specific patients. Clinicians and researchers should also consider the kinematic and kinetic differences between tasks, which cannot necessarily be inferred from muscle activation patterns. PMID:21215636
Non-uniform mixing of quantum walk on cycles
William Adamczak; Kevin Andrew; Leon Bergen; Dillon Ethier; Peter Hernberg; Jennifer Lin; Christino Tamon
2007-08-15
A classical lazy random walk on cycles is known to mix to the uniform distribution. In contrast, we show that a continuous-time quantum walk on cycles exhibit strong non-uniform mixing properties. Our results include the following: - The instantaneous distribution of a quantum walk on most even-length cycles is never uniform. - The average distribution of a quantum walk on any Abelian circulant graph is never uniform. As a corollary, the average distribution of a quantum walk on any standard circulant graph, such as the cycles, complete graphs, and even hypercubes, is never uniform.
The discrete-time quaternionic quantum walk on a graph
Norio Konno; Hideo Mitsuhashi; Iwao Sato
2015-05-04
Recently, the quaternionic quantum walk was formulated by the first author as a generalization of discrete-time quantum walks. We treat the right eigenvalue problem of quaternionic matrices to analysis the spectra of its transition matrix. The way to obtain all the right eigenvalues of a quaternionic matrix is given. From the unitary condition on the transition matrix of the quaternionic quantum walk, we deduce some properties about it. Our main results, Theorem 5.3, determine all the right eigenvalues of a quaternionic quantum walk by use of those of the corresponding weighted matrix. In addition, we give some examples of quaternionic quantum walks and their right eigenvalues.
Universal quantum computation using the discrete-time quantum walk
Lovett, Neil B.; Cooper, Sally; Everitt, Matthew; Trevers, Matthew; Kendon, Viv
2010-04-15
A proof that continuous-time quantum walks are universal for quantum computation, using unweighted graphs of low degree, has recently been presented by A. M. Childs [Phys. Rev. Lett. 102, 180501 (2009)]. We present a version based instead on the discrete-time quantum walk. We show that the discrete-time quantum walk is able to implement the same universal gate set and thus both discrete and continuous-time quantum walks are computational primitives. Additionally, we give a set of components on which the discrete-time quantum walk provides perfect state transfer.
Scaling of the atmosphere of self-avoiding walks
A. L. Owczarek; T. Prellberg
2008-06-06
The number of free sites next to the end of a self-avoiding walk is known as the atmosphere. The average atmosphere can be related to the number of configurations. Here we study the distribution of atmospheres as a function of length and how the number of walks of fixed atmosphere scale. Certain bounds on these numbers can be proved. We use Monte Carlo estimates to verify our conjectures. Of particular interest are walks that have zero atmosphere, which are known as trapped. We demonstrate that these walks scale in the same way as the full set of self-avoiding walks, barring an overall constant factor.
Factors for Lower Walking Speed in Persons with Multiple Sclerosis
Nogueira, Leandro Alberto Calazans; dos Santos, Luciano Teixeira; Sabino, Pollyane Galinari; Alvarenga, Regina Maria Papais; Santos Thuler, Luiz Claudio
2013-01-01
Objective. The purpose of this study was to analyze factors related to lower walking speed in persons with multiple sclerosis (PwMS). Methods. A cross-sectional survey was conducted. The study participants were 120 consecutive PwMS, who were able to walk, even with device assistance. Demographic and clinical data were collected. Walking speed was measured in 10 m walk test. Possible factors were assessed: disability, fatigue, visual functioning, balance confidence, physical activity level, walking impact, cognitive interference, and motor planning. A forward linear multiple regression analysis examined the correlation with lower speed. Results. Lower walking speed was observed in 85% of the patients. Fatigue (41%), recurrent falls (30%), and balance problems were also present, even with mild disability (average EDSS = 2.68). A good level of physical activity was noted in most of the subjects. Dual-task procedure revealed 11.58% of walking speed reduction. Many participants (69.57%) imagined greater walking speed than motor execution (mean ? 28.42%). Physical activity level was the only characteristic that demonstrated no significant difference between the groups (lower versus normal walking speed). Many mobility measures were correlated with walking speed; however, disability, balance confidence, and motor planning were the most significant. Conclusions. Disability, balance confidence, and motor planning were correlated with lower walking speed. PMID:23606966
One-dimensional lazy quantum walks and occupancy rate
NASA Astrophysics Data System (ADS)
Li, Dan; Michael, McGettrick; Zhang, Wei-Wei; Zhang, Ke-Jia
2015-05-01
In this paper, we discuss the properties of lazy quantum walks. Our analysis shows that the lazy quantum walks have O(tn) order of the n-th moment of the corresponding probability distribution, which is the same as that for normal quantum walks. The lazy quantum walk with a discrete Fourier transform (DFT) coin operator has a similar probability distribution concentrated interval to that of the normal Hadamard quantum walk. Most importantly, we introduce the concepts of occupancy number and occupancy rate to measure the extent to which the walk has a (relatively) high probability at every position in its range. We conclude that the lazy quantum walks have a higher occupancy rate than other walks such as normal quantum walks, classical walks, and lazy classical walks. Project supported by the National Natural Science Foundation of China (Grant Nos. 61272057 and 61170270), the Higher Education Young Elite Teacher Project of Beijing, China (Grant No. YETP0475 and YETP0477), the BUPT Excellent Ph. D. Students Foundation (Grant Nos. CX201325 and CX201326), and the China Scholarship Council (Grant No. 201306470046).
Reynolds, Andy M; Leprêtre, Lisa; Bohan, David A
2013-01-01
Correlated random walks are the dominant conceptual framework for modelling and interpreting organism movement patterns. Recent years have witnessed a stream of high profile publications reporting that many organisms perform Lévy walks; movement patterns that seemingly stand apart from the correlated random walk paradigm because they are discrete and scale-free rather than continuous and scale-finite. Our new study of the movement patterns of Tenebrio molitor beetles in unchanging, featureless arenas provides the first empirical support for a remarkable and deep theoretical synthesis that unites correlated random walks and Lévy walks. It demonstrates that the two models are complementary rather than competing descriptions of movement pattern data and shows that correlated random walks are a part of the Lévy walk family. It follows from this that vast numbers of Lévy walkers could be hiding in plain sight. PMID:24196232
A formative evaluation of a family-based walking intervention-Furness Families Walk4Life
2011-01-01
Background The family unit may be an important mechanism for increasing physical activity levels, yet little is known about what types of family-based interventions are effective. This study involved a formative evaluation of a 12 week intervention to encourage walking as a family based activity. The intervention consisted of several key elements including led walks and tailored resources, as well as remote support provided via the telephone. The project aimed to explore factors associated with successful delivery of the programme and to identify areas of improvement for future implementation. Methods A total of nine interviews were undertaken with programme staff who were involved in either the set up or delivery of the intervention. In addition, four interviews and two focus groups were undertaken with participants to explore their experiences of the programme. The analysis involved both deductive and inductive reasoning. Results In total, 114 people participated in the programme, which included 36 adults, 10 adolescents and 68 children (? 10 years of age). Adult participants reported several barriers to walking including concerns over their children's behaviour and their ability to maintain 'control' of their children. Walking in a group with other families gave parents confidence to go out walking with their children and provided a valuable opportunity for social interaction for parents and children alike. The most successful walks incorporated specific destinations and an activity to undertake upon reaching the destination. Incorporating other activities along the way also helped to keep the children engaged. Conclusions The results of this study have highlighted the important contribution that formative research can make in informing and refining a programme to increase appropriateness and effectiveness. The study has helped to highlight the key characteristics associated with delivering a successful walking intervention to young families. It is recommended that practitioners undertake formative research when developing novel health promotion initiatives to help refine the programme protocols. PMID:21810254
Quantum walks with memory - goldfish, elephants and wise old men
Peter P. Rohde; Gavin K. Brennen; Alexei Gilchrist
2012-12-18
Quantum walks have emerged as an interesting approach to quantum information processing, exhibiting many unique properties compared to the analogous classical random walk. Here we introduce a model for a discrete-time quantum walk with memory by endowing the walker with multiple recycled coins and using a physical memory function via a history dependent coin flip. By numerical simulation we observe several phenomena. First in one dimension, walkers with memory have persistent quantum ballistic speed up over classical walks just as found in previous studies of multi-coined walks with trivial memory function. However, measurement of the multi-coin state can dramatically shift the mean of the spatial distribution. Second, we consider spatial entanglement in a two-dimensional quantum walk with memory and find that memory destroys entanglement between the spatial dimensions, even when entangling coins are employed. Finally, we explore behaviour in the presence of spatial randomness and find that in contrast to single coined walks, multi-coined walks do not localise and in fact a memory function can speed up the walk relative to a fully decohered multi-coin walker with trivial memory. We explicitly show how to construct linear optics circuits implementing the walks, and discuss prospects for classical simulation.
Zeno subspace in quantum-walk dynamics
NASA Astrophysics Data System (ADS)
Chandrashekar, C. M.
2010-11-01
We investigate discrete-time quantum-walk evolution under the influence of periodic measurements in position subspace. The undisturbed survival probability of the particle at the position subspace P(0,t) is compared with the survival probability after frequent (n) measurements at interval ?=t/n, P(0,?)n. We show that P(0,?)n>P(0,t) leads to the quantum Zeno effect in position subspace when a parameter ? in the quantum coin operations and frequency of measurements is greater than the critical value, ?>?c and n>nc. This Zeno effect in the subspace preserves the dynamics in coin Hilbert space of the walk dynamics and has the potential to play a significant role in quantum tasks such as preserving the quantum state of the particle at any particular position, and to understand the Zeno dynamics in a multidimensional system that is highly transient in nature.
Equivalence between Szegedy's and Coined Quantum Walks
Renato Portugal
2015-09-29
Coined Quantum Walks (QWs) are being used in many contexts with the goal of understanding quantum systems and building quantum algorithms for quantum computers. Alternative models such as Szegedy's and continuous-time QWs were proposed taking advantage from the fact that quantum theory seems to allow different quantized versions based on the same classical model, in this case, the classical random walk. In this work we show the conditions upon which coined QWs are equivalent to Szegedy's QWs. Those QW models have in common a large class of instances, in the sense that the evolution operators are equal when we convert the graph on which the coined QW takes place into a bipartite graph on which Szegedy's QW takes place and vice versa. We also show that the abstract search algorithm using the coined QW model can be cast into Szegedy's searching framework using directed bipartite graphs with sinks.
Generalized ruin problems and asynchronous random walks
NASA Astrophysics Data System (ADS)
Abad, E.
2005-07-01
We consider a gambling game with two different kinds of trials and compute the duration of the game (averaged over all possible initial capitals of the players) by a mapping of the problem to a 1D lattice walk of two particles reacting upon encounter. The relative frequency of the trials is governed by the synchronicity parameter p of the random walk. The duration of the game is given by the mean time to reaction, which turns out to display a different behavior for even and odd lattices, i.e. this quantity is monotonic in p for odd lattices and non-monotonic for even lattices. In the game picture, this implies that the players minimize the duration of the game by restricting themselves to one type of trial if their joint capital is odd, otherwise a non-symmetric mixture of both trials is needed.
Multifractal random walk in copepod behavior
NASA Astrophysics Data System (ADS)
Schmitt, Francccois G.; Seuront, Laurent
2001-12-01
A 3D copepod trajectory is recorded in the laboratory, using two digital cameras. The copepod undergoes a very structured type of trajectory, with successive moves displaying intermittent amplitudes. We perform a statistical analysis of this 3D trajectory using statistical tools developed in the field of turbulence and anomalous diffusion in natural sciences. We show that the walk belongs to “multifractal random walks”, characterized by a nonlinear moment scaling function for the distance versus time. To our knowledge, this is the first experimental study of multifractal anomalous diffusion in natural sciences. We then propose a new type of stochastic process reproducing these multifractal scaling properties. This can be directly used for stochastic numerical simulations, and is thus of important potential applications in the field of animal movement study, and more generally of anomalous diffusion studies.
Step length and required friction in walking.
Cooper, Ryan C; Prebeau-Menezes, Leif M; Butcher, Michael T; Bertram, John E A
2008-05-01
The effect of step length on minimum required coefficient of friction (microR) during a walking step was isolated from other features that influence the mechanics of foot contact (such as speed). Ground reaction force (GRF) from defined step lengths at consistent forward speed was used to calculate (microR), required coefficent of friction. Some individuals walked in a manner that generated a (microR) that was 50% larger than others, in spite of being restricted to the same speed, step length and step frequency. Unshod subjects had greater (microR) compared to shod subjects except at the shortest step lengths. Understanding the dynamic interaction of applied vertical and horizontal forces is necessary to develop strategies to effectively evaluate unsafe circumstances, or modify behavior and develop safer equipment (at home and/or in the workplace) to deal with adverse footing environments. PMID:17703942
Discovering Walking Technicolor at LHC and Lattice
Koichi Yamawaki
2013-05-28
Walking technicolor, having a large anomalous dimension $\\gamma_m \\simeq 1$ and approximate scale symmetry, predicts Technidilaton, a light composite Higgs as a pseudo-Nambu-Goldstone boson of the approximate scale symmetry, which can be identified with the 125 GeV boson discovered at LHC. I will describe how such a {\\it weakly coupled light composite scalar} can be dynamically realized in the {\\it strongly coupled dynamics}, and can be fit to the current data at LHC, based on the ladder-like computation and the holographic one. I will also present results of our lattice collaboration (LatKMI Collaboration) searching for a walking theory and a light flavor-singlet scalar bound state in large $N_f$ QCD.
Holographic integral equations and walking technicolour
Raul Alvares; Nick Evans; Astrid Gebauer; George James Weatherill
2009-11-10
We study chiral symmetry breaking in the holographic D3-D7 system in a simple model with an arbitrary running coupling. We derive equations for the D7 embedding and show there is a light pion. In particular we present simple integral equations, involving just the running coupling and the quark self energy, for the quark condensate and the pion decay constant. We compare these to the Pagels-Stokar or constituent quark model equivalent. We discuss the implications for walking Technicolour theories. We also perform a similar analysis in the four dimensional field theory whose dual is the non-supersymmetric D3-D5 system and propose that it represents a walking theory in which the quark condensate has dimension 2 + sqrt{3}.
Holographic integral equations and walking technicolor
Alvares, Raul; Evans, Nick; Gebauer, Astrid; Weatherill, George James
2010-01-15
We study chiral symmetry breaking in the holographic D3-D7 system in a simple model with an arbitrary running coupling. We derive equations for the D7 embedding and show there is a light pion. In particular we present simple integral equations, involving just the running coupling and the quark self-energy, for the quark condensate and the pion decay constant. We compare these to the Pagels-Stokar or constituent quark model equivalent. We discuss the implications for walking technicolor theories. We also perform a similar analysis in the four-dimensional field theory whose dual is the nonsupersymmetric D3-D5 system and propose that it represents a walking theory in which the quark condensate has dimension 2+{radical}(3)
Simulating a quantum walk with classical optics
Francisco, D.; Iemmi, C.; Paz, J. P.; Ledesma, S.
2006-11-15
We present an optical module to simulate one step of a quantum walk algorithm. The quantum state of a system with a 2N-dimensional Hilbert space is encoded in the spatial distribution of the amplitude of the electromagnetic field in a plane. In such spatial encoding, the probability amplitude of each state of a basis is associated with the complex electromagnetic amplitude in a given slice of the laser wave front. We discuss the design and operation of an optical module that is used to implement one step of a quantum walk algorithm. Using this module, composed by standard optical elements, the evolution of the quantum state corresponds to the application of a Hadamard gate on a single qubit (representing the two-dimensional quantum coin) followed by a displacement of the N-dimensional quantum walker conditioned on the state of the coin. We show the actual implementation of the method and discuss its characteristics and limitations.
Quantum walks in the density operator picture
Chaobin Liu
2015-06-08
A new approach to quantum walks is presented. Considering a quantum system undergoing some unitary discrete-time evolution in a directed graph G, we think of the vertices of G as sites that are occupied by the quantum system, whose internal state is described by density operators. To formulate the unitary evolution, we define reflections in the tensor product of an internal Hilbert space and a spatial Hilbert space. We then construct unitary channels that govern the evolution of the system in the graph. The discrete dynamics of the system (called quantum walks) is obtained by iterating the unitary channel on the density operator of the quantum system. It turns out that in this framework, the action of the unitary channel on a density operator is described by the usual matrix multiplication.
Quantum Parrondo's games using quantum walks
Adrian P. Flitney
2012-09-11
We study a quantum walk in one-dimension using two different "coin" operators. By mixing two operators, both of which give a biased walk with negative expectation value for the walker position, it is possible to reverse the bias through interference effects. This effect is analogous to that in Parrondo's games, where alternating two losing (gambling) games can produce a winning game. The walker bias is produced by introducing a phase factor into the coin operator, with two different phase factors giving games $A$ and $B$. We give the range of phases for which the Parrondo effect can be obtained with $A$ and $B$ played alternately or in other (repeated) deterministic sequences. The effect is transitory. For sufficiently large times the original bias resumes.
Random walk centrality in interconnected multilayer networks
Solé-Ribalta, Albert; Gómez, Sergio; Arenas, Alex
2015-01-01
Real-world complex systems exhibit multiple levels of relationships. In many cases they require to be modeled as interconnected multilayer networks, characterizing interactions of several types simultaneously. It is of crucial importance in many fields, from economics to biology and from urban planning to social sciences, to identify the most (or the less) influential nodes in a network using centrality measures. However, defining the centrality of actors in interconnected complex networks is not trivial. In this paper, we rely on the tensorial formalism recently proposed to characterize and investigate this kind of complex topologies, and extend two well known random walk centrality measures, the random walk betweenness and closeness centrality, to interconnected multilayer networks. For each of the measures we provide analytical expressions that completely agree with numerically results.
"Feeling younger, walking faster": subjective age and walking speed in older adults.
Stephan, Yannick; Sutin, Angelina R; Terracciano, Antonio
2015-10-01
Walking speed is a key vital sign in older people. Given the implications of slower gait speed, a large literature has identified health-related, behavioral, cognitive, and biological factors that moderate age-related decline in mobility. The present study aims to contribute to existing knowledge by examining whether subjective age, how old or young individuals experience themselves to be relative to their chronological age, contributes to walking speed. Participants were drawn from the 2008 and 2012 waves of the Health and Retirement Study (HRS, N = 2970) and the 2011 and 2013 waves of the National Health and Aging Trends Study (NHATS, N = 5423). In both the HRS and the NHATS, linear regression analysis revealed that a younger subjective age was associated with faster walking speed at baseline and with less decline over time, controlling for age, sex, education, and race. These associations were partly accounted for by depressive symptoms, disease burden, physical activity, cognition, body mass index, and smoking. Additional analysis revealed that feeling younger than one's age was associated with a reduced risk of walking slower than the frailty-related threshold of 0.6 m/s at follow-up in the HRS. The present study provides novel and consistent evidence across two large prospective studies for an association between the subjective experience of age and walking speed of older adults. Subjective age may help identify individuals at risk for mobility limitations in old age and may be a target for interventions designed to mitigate functional decline. PMID:26296609
Quantum Random Walks without a Coin Toss
Apoorva Patel; K. S. Raghunathan; Pranaw Rungta
2005-06-27
We construct a quantum random walk algorithm, based on the Dirac operator instead of the Laplacian. The algorithm explores multiple evolutionary branches by superposition of states, and does not require the coin toss instruction of classical randomised algorithms. We use this algorithm to search for a marked vertex on a hypercubic lattice in arbitrary dimensions. Our numerical and analytical results match the scaling behaviour of earlier algorithms that use a coin toss instruction.
Mesonic spectroscopy of Minimal Walking Technicolor
Luigi Del Debbio; Biagio Lucini; Agostino Patella; Claudio Pica; Antonio Rago
2010-04-19
We investigate the structure and the novel emerging features of the mesonic non-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD-like theory. Our results favor a scenario in which MWT is (almost) conformal in the infrared, while spontaneous chiral symmetry breaking seems less plausible.
Junji Jia; Shinya Matsuzaki; Koichi Yamawaki
2013-01-10
We calculate techni-pion masses of the walking technicolor (WTC), by explicitly evaluating nontrivial contributions from various possible chiral breaking sources in a concrete WTC setting of the one-family model. Our explicit computation of the mass and the coupling in this concrete model setting reveals that the techni-pions are on the order of several hundred GeV in the region to be discovered at LHC.
Random Walks in a Random Environment
Fred Solomon
1975-01-01
Let $\\\\{\\\\alpha_n\\\\}$ be a sequence of independent, identically distributed random variables with $0 \\\\leqq \\\\alpha_n \\\\leqq 1$ for all $n$. The random walk in a random environment on the integers is the sequence $\\\\{X_n\\\\}$ where $X_0 = 0$ and inductively $X_{n+1} = X_n + 1, (X_n - 1)$, with probability $\\\\alpha_{X_n}, (1 - \\\\alpha_{X_n})$. In this paper we consider limit
Walking Habits of Adults with Mental Retardation
ERIC Educational Resources Information Center
Stanish, Heidi I.; Draheim, Christopher C.
2005-01-01
The walking activity of men and women with mental retardation residing in community settings was described. Participants were 38 women (M age = 0.7, SD = 9.5) and 65 men (M age = 35.9, SD = 11.2). They wore pedometers for 7 days. A 2 ? 2 factorial ANOVA indicated no significant gender differences in total step counts or between participants with…
Green function approach for scattering quantum walks
F. M. Andrade; M. G. E. da Luz
2011-12-12
In this work a Green function approach for scattering quantum walks is developed. The exact formula has the form of a sum over paths and always can be cast into a closed analytic expression for arbitrary topologies and position dependent quantum amplitudes. By introducing the step and path operators, it is shown how to extract any information about the system from the Green function. The method relevant features are demonstrated by discussing in details an example, a general diamond-shaped graph.
Walking vector soliton caging and releasing
Kartashov, Yaroslav V; Torner, Lluis
2009-01-01
We address the formation and propagation of vector solitons in optical lattices in the presence of anisotropy-induced walk-off between ordinary and extraordinary polarized field components. Stable vector solitons trapped by the lattice form above a threshold power, while decreasing the lattice depth below a critical value results in the abrupt release of the caged solitons, that then move across the lattice and may get trapped in a desired lattice channel.
Fractal landscape analysis of DNA walks
NASA Technical Reports Server (NTRS)
Peng, C. K.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Sciortino, F.; Simons, M.; Stanley, H. E.
1992-01-01
By mapping nucleotide sequences onto a "DNA walk", we uncovered remarkably long-range power law correlations [Nature 356 (1992) 168] that imply a new scale invariant property of DNA. We found such long-range correlations in intron-containing genes and in non-transcribed regulatory DNA sequences, but not in cDNA sequences or intron-less genes. In this paper, we present more explicit evidences to support our findings.
A Random Walk Picture of Basketball
NASA Astrophysics Data System (ADS)
Gabel, Alan; Redner, Sidney
2012-02-01
We analyze NBA basketball play-by-play data and found that scoring is well described by a weakly-biased, anti-persistent, continuous-time random walk. The time between successive scoring events follows an exponential distribution, with little memory between events. We account for a wide variety of statistical properties of scoring, such as the distribution of the score difference between opponents and the fraction of game time that one team is in the lead.
Hitting probabilities of random walks on
Harry Kesten
1987-01-01
Let S0, S1, ... be a simple (nearest neighbor) symmetric random walk on and HB(x,y) = P{S. visits B for the first time at yS0 = x}. If d = 2 we show that for any connected set B of diameter r, and any y [epsilon] B, one has lim sup HB(x, y) [less-than-or-equals, slant] C(2) r-1\\/2 Â· x -->
Asymptotic properties of a bold random walk
NASA Astrophysics Data System (ADS)
Serva, Maurizio
2014-08-01
In a recent paper we proposed a non-Markovian random walk model with memory of the maximum distance ever reached from the starting point (home). The behavior of the walker is different from the simple symmetric random walk only when she is at this maximum distance, where, having the choice to move either farther or closer, she decides with different probabilities. If the probability of a forward step is higher than the probability of a backward step, the walker is bold and her behavior turns out to be superdiffusive; otherwise she is timorous and her behavior turns out to be subdiffusive. The scaling behavior varies continuously from subdiffusive (timorous) to superdiffusive (bold) according to a single parameter ? ?R. We investigate here the asymptotic properties of the bold case in the nonballistic region ? ?[0,1/2], a problem which was left partially unsolved previously. The exact results proved in this paper require new probabilistic tools which rely on the construction of appropriate martingales of the random walk and its hitting times.
Animal navigation: general properties of directed walks.
Cheung, Allen; Zhang, Shaowu; Stricker, Christian; Srinivasan, Mandyam V
2008-09-01
The ability to locomote is a defining characteristic of all animals. Yet, all but the most trivial forms of navigation are poorly understood. Here we report and discuss the analytical results of an in-depth study of a simple navigation problem. In principle, there are two strategies for navigating a straight course. One is to use an external directional reference and to continually reorient with reference to it. The other is to monitor body rotations from internal sensory information only. We showed previously that, at least for simple representations of locomotion, the first strategy will enable an animal or mobile agent to move arbitrarily far away from its starting point, but the second strategy will not do so, even after an infinite number of steps. This paper extends and generalizes the earlier results by demonstrating that these findings are true even when a very general model of locomotion is used. In this general model, error components within individual steps are not independent, and directional errors may be biased. In the absence of a compass, the expected path of a directed walk in general approximates a logarithmic spiral. Some examples are given to illustrate potential applications of the quantitative results derived here. Motivated by the analytical results developed in this work, a nomenclature for directed walks is proposed and discussed. Issues related to path integration in mammals and robots, and measuring the curvature of a noisy path are also addressed using directed walk theory. PMID:18781320
Modulation of Head Movement Control During Walking
NASA Technical Reports Server (NTRS)
Mulavara, Ajitkumar P.; Verstraete, Mary C.; Bloomberg, Jacob J.; Paloski, William H. (Technical Monitor)
1999-01-01
The purpose of this study was to investigate the coordination of the head relative to the trunk within a gait cycle during gaze fixation. Nine normal subjects walked on a motorized treadmill driven at 1.79 m/sec (20 s trials) while fixing their gaze on a centrally located earth-fixed target positioned at a distance of 2m from their eyes. The relative motion of the head and the net torque acting on it relative to the trunk during the gait cycle were used as measures of coordination. It was found that the net torque applied to the head counteracts the destabilizing forces acting on the upper body during locomotion. The average net torque impulse was significantly different (p less than 0.05) between the heel strike and swing phases and were found to be symmetrical between the right and left leg events of the gait cycle. However, the average net displacement of the head relative to the trunk was maintained uniform (p greater than 0.05) throughout the gait cycle. Thus, the coordination of the motion of the head relative to the trunk during walking is dynamically modulated depending on the behavioral events occurring in the gait cycle. This modulation may serve to aid stabilization of the head by counteracting the force variations acting on the upper body that may aid in the visual fixing of targets during walking.
Random walks on generalized Koch networks
NASA Astrophysics Data System (ADS)
Sun, Weigang
2013-10-01
For deterministically growing networks, it is a theoretical challenge to determine the topological properties and dynamical processes. In this paper, we study random walks on generalized Koch networks with features that include an initial state that is a globally connected network to r nodes. In each step, every existing node produces m complete graphs. We then obtain the analytical expressions for first passage time (FPT), average return time (ART), i.e. the average of FPTs for random walks from node i to return to the starting point i for the first time, and average sending time (AST), defined as the average of FPTs from a hub node to all other nodes, excluding the hub itself with regard to network parameters m and r. For this family of Koch networks, the ART of the new emerging nodes is identical and increases with the parameters m or r. In addition, the AST of our networks grows with network size N as N?ln?N and also increases with parameter m. The results obtained in this paper are the generalizations of random walks for the original Koch network.
From Lévy walks to superdiffusive shock acceleration
Zimbardo, Gaetano; Perri, Silvia, E-mail: gaetano.zimbardo@fis.unical.it, E-mail: silvia.perri@fis.unical.it [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, I-87036 Arcavacata di Rende (Italy)
2013-11-20
In this paper, we present a general scenario for nondiffusive transport and we investigate the influence of anomalous, superdiffusive transport on Fermi acceleration processes at shocks. We explain why energetic particle superdiffusion can be described within the Lévy walk framework, which is based on a power-law distribution of free path lengths and on a coupling between free path length and free path duration. A self-contained derivation of the particle mean square displacement, which grows as (?x {sup 2}) = 2D {sub ?} t {sup ?} with ? > 1, and the particle propagator, is presented for Lévy walks, making use of a generalized version of the Montroll-Weiss equation. We also derive for the first time an explicit expression for the anomalous diffusion coefficient D {sub ?} and we discuss how to obtain these quantities from energetic particle observations in space. The results are applied to the case of particle acceleration at an infinite planar shock front. Using the scaling properties of the Lévy walk propagator, the energy spectral indices are found to have values smaller than the ones predicted by the diffusive shock acceleration theory. Furthermore, when applying the results to ions with energies of a few MeV accelerated at the solar wind termination shock, the estimation of the anomalous diffusion coefficient associated with the superdiffusive motion gives acceleration times much smaller than the ones related to normal diffusion.
Efficacy of Nordic walking in obesity management.
Figard-Fabre, H; Fabre, N; Leonardi, A; Schena, F
2011-06-01
The effects of a Nordic walking (NW) program compared to those of a walking (W) program on physiological and perceptual variables in obese middle-aged women were investigated. Subjects (n=12 NW group, n=11 W group) trained over 12 weeks 3 times.week (-1). Body mass, body mass index (BMI), body fat, heart rate (HR), resting blood pressure, peak oxygen consumption (V?O (2peak)) were measured before and after the training period. Moreover, HR, rating of perceived exertion (RPE) and adherence were recorded during all training sessions. After the training period body mass, body fat and diastolic blood pressure decreased in both groups (P<0.05) whereas V?O (2peak) increased in the NW group (+3.7?ml.min (-1).kg (-1); P=0.005). During the training sessions, mean HR (P=0.021), HR at preferred walking speed (P=0.020) and % of time at high intensity (P=0.031) were higher in NW than in the W group. Finally, RPE was not influenced by the modality of exercise and NW group showed a higher rate of adherence (91±19% vs. 81±29%; P=0.011). To conclude, NW activity in obese women allows an increase in exercise intensity and adherence to a training program without increasing the perception of effort leading to enhanced aerobic capacity. PMID:21472629
Record statistics for random walk bridges
NASA Astrophysics Data System (ADS)
Godrèche, Claude; Majumdar, Satya N.; Schehr, Grégory
2015-07-01
We investigate the statistics of records in a random sequence $\\{x_B(0)=0,x_B(1),\\cdots, x_B(n)=x_B(0)=0\\}$ of $n$ time steps. The sequence $x_B(k)$'s represents the position at step $k$ of a random walk `bridge' of $n$ steps that starts and ends at the origin. At each step, the increment of the position is a random jump drawn from a specified symmetric distribution. We study the statistics of records and record ages for such a bridge sequence, for different jump distributions. In absence of the bridge condition, i.e., for a free random walk sequence, the statistics of the number and ages of records exhibits a `strong' universality for all $n$, i.e., they are completely independent of the jump distribution as long as the distribution is continuous. We show that the presence of the bridge constraint destroys this strong `all $n$' universality. Nevertheless a `weaker' universality still remains for large $n$, where we show that the record statistics depends on the jump distributions only through a single parameter $0<\\mu\\le 2$, known as the L\\'evy index of the walk, but are insensitive to the other details of the jump distribution. We derive the most general results (for arbitrary jump distributions) wherever possible and also present two exactly solvable cases. We present numerical simulations that verify our analytical results.
Integrated system for single leg walking
NASA Astrophysics Data System (ADS)
Simmons, Reid; Krotkov, Eric; Roston, Gerry
1990-07-01
The Carnegie Mellon University Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. This report describes an integrated software system capable of navigating a single leg of the robot over rugged terrain. The leg, based on an early design of the Ambler Planetary Rover, is suspended below a carriage that slides along rails. To walk, the system creates an elevation map of the terrain from laser scanner images, plans an appropriate foothold based on terrain and geometric constraints, weaves the leg through the terrain to position it above the foothold, contacts the terrain with the foot, and applies force enough to advance the carriage along the rails. Walking both forward and backward, the system has traversed hundreds of meters of rugged terrain including obstacles too tall to step over, trenches too deep to step in, closely spaced obstacles, and sand hills. The implemented system consists of a number of task-specific processes (two for planning, two for perception, one for real-time control) and a central control process that directs the flow of communication between processes.
Gait Recognition and Walking Exercise Intensity Estimation
Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang
2014-01-01
Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057
Marselle, Melissa R; Irvine, Katherine N; Warber, Sara L
2013-11-01
The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708) were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale), depression (Major Depressive Inventory), perceived stress (Perceived Stress Scale) and emotional well-being (Positive and Negative Affect Schedule). Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through "green prescriptions" to improve psychological and emotional well-being, as well as physical activity. PMID:24173142
Using a controller based on reinforcement learning for a passive dynamic walking robot
van Vliet, Lucas J.
1 Using a controller based on reinforcement learning for a passive dynamic walking robot E of the difficulties with passive dynamic walking is the stability of walking. In our robot, small uneven or tilted prototype of passive dynamic walking robot with a conventional feedback controller. The successful walking
Building/dept. name & number Address Alexander Theatre (7) 48 Exhibition Walk
Li, Yuan-Fang
and Paper Institute (59) 15 Alliance Lane Bicycle Arrival Station James Gormley (80A) 5 Rainforest Walk Biochemistry Laboratories (16) 11 Chancellors Walk Biological Sciences (18) 25 Rainforest Walk Biological Sciences Lecture Theatres S7 S8 (21) 21 Rainforest Walk Biology (17) 18 Innovation Walk Boiler House (38
Takeshima, Nobuo; Islam, Mohammod M.; Rogers, Michael E.; Rogers, Nicole L.; Sengoku, Naoko; Koizumi, Daisuke; Kitabayashi, Yukiko; Imai, Aiko; Naruse, Aiko
2013-01-01
The purpose of this study was to compare the effects of Nordic walking with conventional walking and band-based resistance exercise on functional fitness, static balance and dynamic balance in older adults. Volunteers (n = 65) were divided into four groups: Nordic walking (NW), conventional walking (CW), resistance (RES), and control. Each group performed activity 50-70 min·day?1 (warm-up 10-15 min, main exercise 30-40, and cool down 10-15 min), 3 days·week?1 (NW and CW) or 2 day·week?1 (RES) for 12 wks. Upper-body strength improved (p < 0. 05) in the RES (22.3%) and the NW (11.6%) groups compared to the CW and control groups. Cardio- respiratory fitness improved more in the NW (10.9%) and CW (10.6%) groups compared to the RES and control groups. Upper- and lower-body flexibility also improved in all exercise groups compared to the control group. There were no improvements in balance measures in any group. While all modes of exercise improved various components of fitness, Nordic walking provided the best well-rounded benefits by improving upper-body strength, cardiovascular endurance, and flexibility. Therefore, Nordic walking is recommended as an effective and efficient mode of concurrent exercise to improve overall functional fitness in older adults. Key Points Nordic walking, conventional walking, and resistance training are beneficial for older adults. Nordic walking and conventional walking both improve cardio-respiratory fitness while resistance training does not. Nordic walking provides additional benefits in upper-body muscular strength compared to conventional walking. Nordic walking is an effective and efficient mode of exercise to improve overall fitness in older adults. PMID:24149147
Comparison of rearfoot motion in overground versus treadmill walking.
Lemke, K; Cornwall, M W; McPoil, T G; Schuit, D
1995-05-01
The purpose of this study was to determine whether walking on a treadmill is a valid simulator of overground walking with respect to rearfoot motion. The tibial, calcaneal, and rearfoot motions of 10 subjects (2 males, 8 females) were videotaped while they walked on a treadmill and overground. The results of a series of t-tests showed that there was no statistically significant difference between the two conditions on any of the variables measured. PMID:7776212
Mall Walking Program Environments, Features, and Participants: A Scoping Review
Belza, Basia; Allen, Peg; Brolliar, Sarah; Brown, David R.; Cormier, Marc L.; Janicek, Sarah; Jones, Dina L.; King, Diane K.; Marquez, David X.; Rosenberg, Dori E.
2015-01-01
Introduction Walking is a preferred and recommended physical activity for middle-aged and older adults, but many barriers exist, including concerns about safety (ie, personal security), falling, and inclement weather. Mall walking programs may overcome these barriers. The purpose of this study was to summarize the evidence on the health-related value of mall walking and mall walking programs. Methods We conducted a scoping review of the literature to determine the features, environments, and benefits of mall walking programs using the RE-AIM framework (reach, effectiveness, adoption, implementation, and maintenance). The inclusion criteria were articles that involved adults aged 45 years or older who walked in indoor or outdoor shopping malls. Exclusion criteria were articles that used malls as laboratory settings or focused on the mechanics of walking. We included published research studies, dissertations, theses, conference abstracts, syntheses, nonresearch articles, theoretical papers, editorials, reports, policy briefs, standards and guidelines, and nonresearch conference abstracts and proposals. Websites and articles written in a language other than English were excluded. Results We located 254 articles on mall walking; 32 articles met our inclusion criteria. We found that malls provided safe, accessible, and affordable exercise environments for middle-aged and older adults. Programmatic features such as program leaders, blood pressure checks, and warm-up exercises facilitated participation. Individual benefits of mall walking programs included improvements in physical, social, and emotional well-being. Limited transportation to the mall was a barrier to participation. Conclusion We found the potential for mall walking programs to be implemented in various communities as a health promotion measure. However, the research on mall walking programs is limited and has weak study designs. More rigorous research is needed to define best practices for mall walking programs’ reach, effectiveness, adoption, implementation, and maintenance. PMID:26270743
Walk-in refrigerators are key to proper cold storage.
Townsend, R
1991-06-12
Often overlooked as an important kitchen design element, properly sized refrigeration and freezing equipment is an important contributor to a kitchen's functionality. In many operations, particularly large-volume units, walk-in refrigerators are the anchors of a good cold-storage system. A walk through three different foodservice operations--a college, a hotel and a hospital--finds walk-ins at work. PMID:10112028
The bottom-supported walking drilling rig Shengli-2
Gu Xinyi; Bin Ruji; Ma Zhiliang; Chen Jianyuan
1993-12-31
A new type of offshore rig--the bottom supported walking drilling rig was developed in China and has been completed successfully. It is rig Shengli-2. Rig Shengli-2 consists of an inner body and outer body. In condition of mutual support they can be seated down and lifted up alternatively and can also be moved forward (or backward) by means of the hydraulic walking mechanism which makes the walking possible.
Qubit state transfer via discrete-time quantum walks
NASA Astrophysics Data System (ADS)
Yalç?nkaya, ?skender; Gedik, Zafer
2015-06-01
We propose a scheme for perfect transfer of an unknown qubit state via the discrete-time quantum walk on a line or a circle. For this purpose, we introduce an additional coin operator which is applied at the end of the walk. This operator does not depend on the state to be transferred. We show that perfect state transfer over an arbitrary distance can be achieved only if the walk is driven by an identity or a flip coin operator. Other biased coin operators and the Hadamard coin allow perfect state transfer over finite distances only. Furthermore, we show that quantum walks ending with a perfect state transfer are periodic.
Qubit state transfer via discrete-time quantum walks
?. Yalç?nkaya; Z. Gedik
2015-05-27
We propose a scheme for perfect transfer of an unknown qubit state via the discrete-time quantum walk on a line or a circle. For this purpose, we introduce an additional coin operator which is applied at the end of the walk. This operator does not depend on the state to be transferred. We show that perfect state transfer over an arbitrary distance can be achieved only if the walk is driven by an identity or a flip coin operator. Other biased coin operators and Hadamard coin allow perfect state transfer over finite distances only. Furthermore, we show that quantum walks ending with a perfect state transfer are periodic.
18.366 Random Walks and Diffusion, Spring 2005
Bazant, Martin Z.
Discrete and continuum modeling of diffusion processes in physics, chemistry, and economics. Topics include central limit theorems, continuous-time random walks, Levy flights, correlations, extreme events, mixing, ...
Discrete-time interacting quantum walks and quantum Hash schemes
NASA Astrophysics Data System (ADS)
Li, Dan; Zhang, Jie; Guo, Fen-Zhuo; Huang, Wei; Wen, Qiao-Yan; Chen, Hui
2013-03-01
Through introducing discrete-time quantum walks on the infinite line and on circles, we present a kind of two-particle interacting quantum walk which has two kinds of interactions. We investigate the characteristics of this kind of quantum walk and the time evolution of the two particles. Then we put forward a kind of quantum Hash scheme based on two-particle interacting quantum walks and discuss their feasibility and security. The security of this kind of quantum Hash scheme relies on the infinite possibilities of the initial state rather than the algorithmic complexity of hard problems, which will greatly enhance the security of the Hash schemes.
Walking control of small size humanoid robot: HAJIME ROBOT 18
NASA Astrophysics Data System (ADS)
Sakamoto, Hajime; Nakatsu, Ryohei
2007-12-01
HAJIME ROBOT 18 is a fully autonomous biped robot. It has been developed for RoboCup which is a worldwide soccer competition of robots. It is necessary for a robot to have high mobility to play soccer. High speed walking and all directional walking are important to approach and to locate in front of a ball. HAJIME ROBOT achieved these walking. This paper describes walking control of a small size humanoid robot 'HAJIME ROBOT 18' and shows the measurement result of ZMP (Zero Moment Point). HAJIME ROBOT won the Robotics Society of Japan Award in RoboCup 2005 and in RoboCup 2006 Japan Open.
18.366 Random Walks and Diffusion, Spring 2003
Bazant, Martin Z.
Discrete and continuum modeling of diffusion processes in physics, chemistry, and economics. Topics include central limit theorems, continuous-time random walks, Levy flights, correlations, extreme events, mixing, ...
Walking and wheelchair energetics in persons with paraplegia.
Cerny, D; Waters, R; Hislop, H; Perry, J
1980-09-01
The energetics of walking with orthoses and wheelchair propulsion at free velocity were tested in 10 adults with low-level spinal cord injuries. Eight were subjects who customarily used wheelchairs as their primary mode of locomotion; the other two used orthoses and had discontinued use of their wheelchairs. All required bilateral knee-ankle-foot orthoses to walk. A third habitual walker also was tested during walking only. Patients walked or propelled their wheelchairs around a 60.5-meter outdoor cement track. Heart rate, respiratory rate, and step frequency were recorded and transmitted by radiotelemetry. Expired air was collected for gas analysis in a polyethylene bag during the activity after a three-minute warm-up. During wheelchair propulsion all subjects demonstrated physiological responses within normal limits. Walking was significantly more difficult to perform than wheelchair propulsion (p < .005). Subjects who customarily used orthoses walked at a mean velocity of 59 +/- 5 m/min; those who primarily used wheelchairs had a mean walking velocity of 22 +/- 13 m/min. Oxygen uptake per minute was similar for both groups. These data suggest that the wheelchair will be the primary mode of locomotion for persons with spinal cord injury who need two knee-ankle-foot orthoses to walk, unless they are willing to work under anaerobic conditions and can walk at a velocity of 54 m/min or better. PMID:7413741
Implementing Quantum Walks Using Orbital Angular Momentum of Classical Light
Sandeep K Goyal; Filippus S Roux; Andrew Forbes; Thomas Konrad
2013-07-07
We present an implementation scheme for a quantum walk in the orbital angular momentum space of a laser beam. The scheme makes use of a ring interferometer, containing a quarter-wave plate and a q plate. This setup enables one to perform an arbitrary number of quantum walk steps. In addition, the classical nature of the implementation scheme makes it possible to observe the quantum walk evolution in real time. We use nonquantum entanglement of the laser beam's polarization with its orbital angular momentum to implement the quantum walk.
Licence, Sammy; Smith, Robynne; McGuigan, Miranda P.; Earnest, Conrad P.
2015-01-01
Objectives Mobile phone texting is a common daily occurrence with a paucity of research examining corresponding gait characteristics. To date, most studies have participants walk in a straight line vs. overcoming barriers and obstacles that occur during regular walking. The aim of our study is to examine the effect of mobile phone texting during periods of cognitive distraction while walking and negotiating barriers synonymous with pedestrian traffic. Methods Thirty participants (18-50y) completed three randomized, counter-balanced walking tasks over a course during: (1) normal walking (control), (2) texting and walking, and (3) texting and walking whilst being cognitively distraction via a standard mathematical test performed while negotiating the obstacle course. We analyzed gait characteristics during course negotiation using a 3-dimensional motion analysis system and a general linear model and Dunnet-Hsu post-hoc procedure the normal walking condition to assess gait characteristic differences. Primary outcomes included the overall time to complete the course time and barrier contact. Secondary outcomes included obstacle clearance height, step frequency, step time, double support phase and lateral deviation. Results Participants took significantly longer (mean ± SD) to complete the course while texting (24.96±4.20 sec) and during cognitive distraction COG (24.09±3.36 sec) vs. normal walking (19.32±2.28 sec; all, P<0.001). No significant differences were noted for barrier contacts (P = 0.28). Step frequency, step time, double support phase and lateral deviation all increased in duration during the texting and cognitive distraction trial. Texting and being cognitively distracted also increased obstacle clearance versus the walking condition (all, P<0.02). Conclusions Texting while walking and/or being cognitively distracted significantly affect gait characteristics concordant to mobile phone usage resulting in a more cautious gate pattern. Future research should also examine a similar study in older participants who may be at a greater risk of tripping with such walking deviations. PMID:26222430
Code of Federal Regulations, 2010 CFR
2010-01-01
...method for the measurement of energy consumption of walk-in coolers and walk-in...method for the measurement of energy consumption of walk-in coolers and walk-in...measuring, pursuant to EPCA, the energy consumption of refrigerated bottled...
John Cleese demonstrates the work of the Ministry of Silly Walks
Collins, Steven H.
by metabolic rate by 12 per cent, which is quite a lot of walking, about the same as walking 20 per cent purpose because it was a vestigial relic left over from when our animal ancestors walked on all fours
LETTER doi:10.1038/nature14288 Reducing the energy cost of human walking using an
Collins, Steven H.
LETTER doi:10.1038/nature14288 Reducing the energy cost of human walking using an unpowered walking can bepartlyreplacedbypowerinputfromanexoskeleton2 the metabolic rate of human walking canbe reduced by an unpowered ankle exoskeleton. We built a lightweight
Federal Register 2010, 2011, 2012, 2013, 2014
2013-05-01
...Comment Request; Walking-Working Surfaces Standard ACTION...ICR) titled, ``Walking-Working Surfaces Standard,'' to...requirements in the Walking-Working Surfaces Standard protect workers...authorized agent, in a conspicuous place in each space to which...
Walking the GPS Line : Insights on the use of shape walking as a game mechanic
Josephine Reid; Chris Bevan
In this paper we describe an experiment to investigate and ascertain the feasibility of utilizing GPS tracking as a control mechanism in a mobile game. The interaction mechanism tested was that of walking shapes and we examine the user response to this novel form of game mechanic. We discuss the difficulty in developing a good cognitive model of how GPS
Discrete-Time Quantum Walk - Dynamics and Applications
C. M. Chandrashekar
2010-06-24
This dissertation presents investigations on dynamics of discrete-time quantum walk and some of its applications. Quantum walks has been exploited as an useful tool for quantum algorithms in quantum computing. Beyond quantum computational purposes, it has been used to explain and control the dynamics in various physical systems. In order to use the quantum walk to its fullest potential, it is important to know and optimize the properties purely due to quantum dynamics and in presence of noise. Various studies of its dynamics in the absence and presence of noise have been reported. We propose new approaches to optimize the dynamics, discuss symmetries and effect of noise on the quantum walk. Making use of its properties, we propose the use of quantum walk as an efficient new tool for various applications in physical systems and quantum information processing. In the first and second part of this dissertation, we discuss evolution process of the quantum walks, propose and demonstrate the optimization of discrete-time quantum walk using quantum coin operation from SU(2) group and discuss some of its properties. We investigate symmetry operations and environmental effects on dynamics of the walk on a line and an n-cycle highlighting the interplay between noise and topology. Using the properties and behavior of quantum walk discussed in part two, in part three we propose the application of quantum walk to realize quantum phase transition in optical lattice, that is to efficiently control and redistribute ultracold atoms in optical lattice. We also discuss the implementation scheme. Another application we consider is creation of spatial entanglement using quantum walk on a quantum many body system.
Inferring Lévy walks from curved trajectories: A rescaling method
NASA Astrophysics Data System (ADS)
Tromer, R. M.; Barbosa, M. B.; Bartumeus, F.; Catalan, J.; da Luz, M. G. E.; Raposo, E. P.; Viswanathan, G. M.
2015-08-01
An important problem in the study of anomalous diffusion and transport concerns the proper analysis of trajectory data. The analysis and inference of Lévy walk patterns from empirical or simulated trajectories of particles in two and three-dimensional spaces (2D and 3D) is much more difficult than in 1D because path curvature is nonexistent in 1D but quite common in higher dimensions. Recently, a new method for detecting Lévy walks, which considers 1D projections of 2D or 3D trajectory data, has been proposed by Humphries et al. The key new idea is to exploit the fact that the 1D projection of a high-dimensional Lévy walk is itself a Lévy walk. Here, we ask whether or not this projection method is powerful enough to cleanly distinguish 2D Lévy walk with added curvature from a simple Markovian correlated random walk. We study the especially challenging case in which both 2D walks have exactly identical probability density functions (pdf) of step sizes as well as of turning angles between successive steps. Our approach extends the original projection method by introducing a rescaling of the projected data. Upon projection and coarse-graining, the renormalized pdf for the travel distances between successive turnings is seen to possess a fat tail when there is an underlying Lévy process. We exploit this effect to infer a Lévy walk process in the original high-dimensional curved trajectory. In contrast, no fat tail appears when a (Markovian) correlated random walk is analyzed in this way. We show that this procedure works extremely well in clearly identifying a Lévy walk even when there is noise from curvature. The present protocol may be useful in realistic contexts involving ongoing debates on the presence (or not) of Lévy walks related to animal movement on land (2D) and in air and oceans (3D).
When to walk away from a deal.
Cullinan, Geoffrey; Le Roux, Jean-Marc; Weddigen, Rolf-Magnus
2004-04-01
Deal making is glamorous; due diligence is not. That simple statement goes a long way toward explaining why so many companies have made so many acquisitions that have produced so little value. The momentum of a transaction is hard to resist once senior management has the target in its sights. Companies contract "deal fever," and due diligence all too often becomes an exercise in verifying the target's financial statements rather than conducting a fair analysis of the deal's strategic logic and the acquirer's ability to realize value from it. Seldom does the process lead managers to kill potential acquisitions, even when the deals are deeply flawed. In a recent Bain & Company survey of 250 international executives with M&A responsibilities, only 30% of them were satisfied with the rigor of their due diligence. And fully a third admitted they hadn't walked away from deals they had nagging doubts about. In this article, the authors, all Bain consultants, emphasize the importance of comprehensive due diligence practices and suggest ways companies can improve their capabilities in this area. They provide rich real-world examples of companies that have had varying levels of success with their due diligence processes, including Safeway, Odeon, American Sea-foods, and Kellogg's. Effective due diligence requires answering four basic questions: What are we really buying? What is the target's stand-alone value? Where are the synergies--and the skeletons? And what's our walk-away price? Each of these questions will prompt an even deeper level of querying that puts the broader, strategic rationale for acquisitions under a microscope. Successful acquirers pay close heed to the results of such in-depth investigations and analyses--to the extent that they are prepared to walk away from a deal, even in the very late stages of negotiations. PMID:15077370
Quantum-walk-based search and centrality
NASA Astrophysics Data System (ADS)
Berry, Scott D.; Wang, Jingbo B.
2010-10-01
We study the discrete-time quantum-walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and the position of the marked vertex, in particular, its centrality. We find that the maximum value of the search probability does not necessarily increase as the marked vertex becomes more central, and we investigate an interesting relationship between the frequency of the successful search probability and the centrality of the marked vertex.
Quantum-walk-based search and centrality
Berry, Scott D.; Wang, Jingbo B. [School of Physics, The University of Western Australia, Perth, WA 6009 (Australia)
2010-10-15
We study the discrete-time quantum-walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and the position of the marked vertex, in particular, its centrality. We find that the maximum value of the search probability does not necessarily increase as the marked vertex becomes more central, and we investigate an interesting relationship between the frequency of the successful search probability and the centrality of the marked vertex.
Novel image encryption based on quantum walks.
Yang, Yu-Guang; Pan, Qing-Xiang; Sun, Si-Jia; Xu, Peng
2015-01-01
Quantum computation has achieved a tremendous success during the last decades. In this paper, we investigate the potential application of a famous quantum computation model, i.e., quantum walks (QW) in image encryption. It is found that QW can serve as an excellent key generator thanks to its inherent nonlinear chaotic dynamic behavior. Furthermore, we construct a novel QW-based image encryption algorithm. Simulations and performance comparisons show that the proposal is secure enough for image encryption and outperforms prior works. It also opens the door towards introducing quantum computation into image encryption and promotes the convergence between quantum computation and image processing. PMID:25586889
Random Walk on Random Infinite Looptrees
NASA Astrophysics Data System (ADS)
Björnberg, Jakob E.; Stefánsson, Sigurdur Örn
2015-03-01
Looptrees have recently arisen in the study of critical percolation on the uniform infinite planar triangulation. Here we consider random infinite looptrees defined as the local limit of the looptree associated with a critical Galton-Watson tree conditioned to be large. We study simple random walk on these infinite looptrees by means of providing estimates on volume and resistance growth. We prove that if the offspring distribution of the Galton-Watson process is in the domain of attraction of a stable distribution with index then the spectral dimension of the looptree is.
Lamplighter random walks on fractals Takashi Kumagai
3, c4 > 0 such that c1 ndf /dw exp c2 d(x, y)dw n 1/(dw 1) ! h2n(x, y) c3 ndf /dw exp c4 d(x, y)dw n 1/(dw 1) ! (1.3) holds for all d(x, y) 2n (note that h2n(x, y) = 0 when d(x, y) > 2n), where d(Â·, Â·) is the graph distance, df is the volume growth exponent of the fractal graph and dw is called a walk dimension
Light dilaton in walking gauge theories
Appelquist, Thomas; Bai Yang
2010-10-01
We analyze the existence of a dilaton in gauge theories with approximate infrared conformal symmetry. To the extent that these theories are governed in the infrared by an approximate fixed point (walking), the explicit breaking of the conformal symmetry at these scales is vanishingly small. If confinement and spontaneous chiral-symmetry breaking set in at some infrared scale, the resultant breaking of the approximate conformal symmetry can lead to the existence of a dilaton with mass parametrically small compared to the confinement scale, and potentially observable at the LHC.
Planning strategies for the Ambler walking robot
NASA Technical Reports Server (NTRS)
Wettergreen, David; Thomas, Hans; Thorpe, Chuck
1990-01-01
A hierarchy of planning strategies is proposed and explained for a walking robot called the Ambler. The hierarchy decomposes planning into levels of trajectory, gait, and footfall. An abstraction of feasible traversability allows the Ambler's trajectory planner to identify acceptable trajectories by finding paths that guarantee footfalls without specifying exactly which footfalls. Leg and body moves that achieve this trajectory can be generated by the Ambler's gait planner, which incorporates pattern constraints and measures of utility to search for the best next move. By combining constraints from the quality and details of the terrain, the Ambler's footfall planner can select footfalls that insure stability and remain within the tolerances of the gait.
Access Excellence: A Walk Through the Gut
NSDL National Science Digital Library
Ward, Vivian Lee
2007-12-12
Hosted by the Access Excellence at the National Health Museum, this website features A Walk Through the Gut, a lesson created for high school students by educator VivianLee Ward. This hands-on lesson promotes cooperative learning by directing students to work together as they simulate and analyze the passage of food through the digestive system. Ms. Ward designed this one-hour life sciences lesson for special education and special needs students as well. The site includes short sections on Materials, Procedure / Description of Lesson, Group Questions, and more.
Random walk computations of diffusive fields
Lindstrom, Gregory Scot
1993-01-01
:36 REFERENCES . . 37 APPENDIX A FOURIER SERIFS SOLI. TION OF THE HEAT V@I, ATION . . :39 vn APPENDIX B INITIALIZATION ROUTINE Page 41 Intialization Source Code. 43 C GRADIENT RANDOM WALK SOURCE CODE . , 50 Main Program Add a glob... were run on a Sun SPARCstation IPC computer running SunOS 4. 1, 2 (UNIX). The program is written in the C programming language (see appendix B for source code) with all graphical work performed under "PV-Wave" software from Precision Visuals, lnc. 2...
NSDL National Science Digital Library
Engineering K-PhD Program,
Students experience a simulation of echolation, using the sensory method to walk along a path while blindfolded. This relates to the issue of bycatching by fisheries, which they learned about In the associated lesson. Bycatching affects marine animals, especially dolphins, which use echolocation to identify the location of objects in the water, but have difficulty identifying nets, and thus are often caught accidentally. Students learn how echolocation works, why certain animals use it to determine the size, shape and distance of objects, and how humans can potentially take advantage of dolphins' echolocation ability when developing bycatch avoidance methods.
Biased random walks and propagation failure.
Méndez, Vicenç; Fedotov, Sergei; Campos, Daniel; Horsthemke, Werner
2007-01-01
The critical value of the reaction rate able to sustain the propagation of an invasive front is obtained for general non-Markovian biased random walks with reactions. From the Hamilton-Jacobi equation corresponding to the mean field equation we find that the critical reaction rate depends only on the mean waiting time and on the statistical properties of the jump length probability distribution function and is always underestimated by the diffusion approximation. If the reaction rate is larger than the jump frequency, invasion always succeeds, even in the case of maximal bias. Numerical simulations support our analytical predictions. PMID:17358121
Random walk on random infinite looptrees
Jakob E. Björnberg; Sigurdur Örn Stefánsson
2015-05-29
Looptrees have recently arisen in the study of critical percolation on the uniform infinite planar triangulation. Here we consider random infinite looptrees defined as the local limit of the looptree associated with a critical Galton--Watson tree conditioned to be large. We study simple random walk on these infinite looptrees by means of providing estimates on volume and resistance growth. We prove that if the offspring distribution of the Galton--Watson process is in the domain of attraction of a stable distribution with index $\\alpha\\in(1,2]$ then the spectral dimension of the looptree is $2\\alpha/(\\alpha+1)$.
Sequencing a Genome by Walking With Clone-end Sequences
Sequencing a Genome by Walking With Clone-end Sequences: A Mathematical Analysis Serafim Batzoglou-insert clones (such as bacterial artificial chromosomes (BACs)) and then (ii) to take successive 'walking' steps by selecting and sequencing minimally overlapping clones, using information such as clone-end sequences
Children's Physical Activity: The Contribution of Playing and Walking
ERIC Educational Resources Information Center
Mackett, Roger L.; Paskins, James
2008-01-01
This paper draws on research in which 200 children were fitted with motion sensors and asked to keep travel and activity diaries. The findings show that walking and playing away from home can contribute significantly to children's volume of physical activity, with consequent implications for their health. Not only do both playing and walking…
GATED--TYPE POLLING SYSTEMS WITH WALKING AND SWITCHIN TIMES
GATED--TYPE POLLING SYSTEMS WITH WALKING AND SWITCHIN TIMES Eitan ALTMAN INRIA Centre Sophia of Statistics and OR TelAviv University TelAviv 69978, Israel Keywords: Polling, Walking times, Switchin times, Threshold, Gated, GloballyGated. ABSTRACT We consider models of polling systems where switching
Recycling Energy to Restore Impaired Ankle Function during Human Walking
Collins, Steven H.
Recycling Energy to Restore Impaired Ankle Function during Human Walking Steven H. Collins1 that captures some of the energy that is normally dissipated by the leg and ``recycles'' it as positive ankle walking. Energy recycling restored ankle push-off to normal and reduced the net metabolic energy penalty
Motion in Cell Membranes, General Random Walks and Anomalous Diffusion
Steinberg, Stanly
Motion in Cell Membranes, General Random Walks and Anomalous Diffusion Erik Andries , Stanly 6 Examples of Two Dimensional Random Walks 21 7 Summary 24 2 #12;Abstract Cell membranes display and temporal regulation of signal transduction from the cell membrane to the cytoplasm and nucleus is crucial
BIASED RANDOM WALKS ON GALTON-WATSON TREES WITH LEAVES
BIASED RANDOM WALKS ON GALTON-WATSON TREES WITH LEAVES GÂ´ERARD BEN AROUS, ALEXANDER FRIBERGH, NINA GANTERT, AND ALAN HAMMOND Abstract. We consider a biased random walk Xn on a Galton-Watson tree. Key tools for the proof are the classical Harris decomposition for Galton-Watson trees, a new variant
Biased random walk on critical Galton-Watson trees
Kumagai, Takashi
Biased random walk on critical Galton-Watson trees conditioned to survive D. A. Croydon , A. Fribergh and T. Kumagai September 28, 2012 Abstract We consider the biased random walk on a critical Galton-Watson are a natural setting to witness trapping phenomena. In the case of supercritical Galton-Watson trees
PATH OPTIMIZATION FOR HUMANOID WALK PLANNING: AN EFFICIENT APPROACH
Lamiraux, Florent
, France aelkhour@laas.fr, taix@laas.fr, florent@laas.fr Keywords: humanoid robot, motion planning, walk-optimal. This method is validated in various scenarios on the humanoid robot HRP-2. 1 RELATED WORK AND CONTRIBUTION The problem of humanoid walk planning can be defined as follows: given an environment and a humanoid robot
The Fibonacci quantum walk and its cassical trace map
Alejandro Romanelli
2008-02-15
We study the quantum walk in momentum space using a coin arranged in quasi-periodic sequences following a Fibonacci prescription. We build for this system a classical map based on the trace of the evolution operator. The sub-ballistic behavior of this quantum walk is connected with the power-law decay of the time correlations of the trace map.
79 FR 15278 - Public Use Limit on Commercial Dog Walking
Federal Register 2010, 2011, 2012, 2013, 2014
2014-03-19
...regarding interim commercial dog management for Areas A and B...citation for part 1002 continues to read as follows: Authority: 16 U...0 2. Add Sec. 1002.6 to read as follows: Sec. 1002.6 Commercial Dog Walking. (a) The walking...
79 FR 48990 - Public Use Limit on Commercial Dog Walking
Federal Register 2010, 2011, 2012, 2013, 2014
2014-08-19
...regarding interim commercial dog management for Areas A and B...citation for part 1002 continues to read as follows: Authority: 16 U...0 2. Add Sec. 1002.6 to read as follows: Sec. 1002.6 Commercial dog walking. (a) The walking...
Human pair walking behavior: evaluation of cooperation strategies
NASA Astrophysics Data System (ADS)
Dobramysl, Ulrich; Bodova, Katarina; Kollar, Richard; Erban, Radek
2015-03-01
Human walkers are notoriously poor at keeping a direction without external cues: Experimental work by Souman et al. with blindfolded subjects told to walk in a straight line revealed intriguing circular and spiraling trajectories, which can be approximated by a stochastic process. In this work, motivated by pair walking experiments by Miglierini et al., we introduce an analysis of various strategies employed by a pair of blindfolded walkers, who are communicating via auditory cues, to maximize their efficiency at walking straight. To this end, we characterize pairs of strategies such as free walking, side-by-side walking and unconditional following from data generated by robot pair walking experiments (using computer vision techniques) and numerical simulations. We extract the mean exit distances of walker pairs from a corridor with finite width to construct phase portraits of the walking performance. We find intriguing cooperative effects leading to non-trivial enhancements of the efficiency at walking straight. The research leading to these results has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC Grant Agreement No. 239870; and from the Royal Society through a Research Grant.
Infant Language Development Is Related to the Acquisition of Walking
ERIC Educational Resources Information Center
Walle, Eric A.; Campos, Joseph J.
2014-01-01
The present investigation explored the question of whether walking onset is related to infant language development. Study 1 used a longitudinal design (N = 44) to assess infant locomotor and language development every 2 weeks from 10 to 13.5 months of age. The acquisition of walking was associated with a significant increase in both receptive and…
ARCHITECTURE The tour will take an hour to walk.
Boucherie, Richard J.
ARCHITECTURE & ART The tour will take an hour to walk. Refreshments during your tour are available 12 1518 20 27 28 31 34 architecture & art a walking tour of the campus colophon Extra info1 Het. Timmerman, , 2011. See also: www.groteA.nl The Art & Architecture Route is a publication of December 2013
Psycho?Logical?Bulletin "Walking to the Sky at CMU"
Spirtes, Peter
Psycho?Logical?Bulletin March 2006 "Walking to the Sky at CMU" Courtesy of Ralph "Hulk" Horgan, and then let your dog sleep on the throw pillow! Hung over from drinking too much beer from your Plaid Brain stein? Sensitive to light? Just walk right over to your Plaid Brain lightswitch faceplate and turn off
Chinese City Children and Youth's Walking Behavior
ERIC Educational Resources Information Center
Quan, Minghui; Chen, Peijie; Zhuang, Jie; Wang, Chao
2013-01-01
Purpose: Although walking has been demonstrated as one of the best forms for promoting physical activity (PA), little is known about Chinese city children and youth's walking behavior. The purpose of this study was therefore to assess ambulatory PA behavior of Chinese city children and youth. Method: The daily steps of 2,751 children and…
Summarization of Egocentric Moving Videos for Generating Walking Route Guidance
Yanai, Keiji
Summarization of Egocentric Moving Videos for Generating Walking Route Guidance Masaya Okamoto to summarize an ego- centric moving video (a video recorded by a moving wearable camera) for generating a walking route guidance video. To summarize an ego- centric video, we analyze it by applying pedestrian
Universal computation by multi-particle quantum walk
Andrew M. Childs; David Gosset; Zak Webb
2013-02-15
A quantum walk is a time-homogeneous quantum-mechanical process on a graph defined by analogy to classical random walk. The quantum walker is a particle that moves from a given vertex to adjacent vertices in quantum superposition. Here we consider a generalization of quantum walk to systems with more than one walker. A continuous-time multi-particle quantum walk is generated by a time-independent Hamiltonian with a term corresponding to a single-particle quantum walk for each particle, along with an interaction term. Multi-particle quantum walk includes a broad class of interacting many-body systems such as the Bose-Hubbard model and systems of fermions or distinguishable particles with nearest-neighbor interactions. We show that multi-particle quantum walk is capable of universal quantum computation. Since it is also possible to efficiently simulate a multi-particle quantum walk of the type we consider using a universal quantum computer, this model exactly captures the power of quantum computation. In principle our construction could be used as an architecture for building a scalable quantum computer with no need for time-dependent control.
Oriented Walk Double Covering and Bidirectional Double Tracing
Zhu, Xuding
Oriented Walk Double Covering and Bidirectional Double Tracing Fan Hongbing Mathematics Department Zhu #3; Department of Applied Mathematics National Sun Yat-sen University Kaohsiung, Taiwan 80424 Email: zhu@math.nsysu.edu.tw; Fax: 886-7-5253809 Abstract An oriented walk double covering of a graph G
Oriented Walk Double Covering and Bidirectional Double Tracing
Zhu, Xuding
Oriented Walk Double Covering and Bidirectional Double Tracing Fan Hongbing Mathematics Department Zhu Department of Applied Mathematics National Sun Yat-sen University Kaohsiung, Taiwan 80424 Email: zhu@math.nsysu.edu.tw; Fax: 886-7-5253809 Abstract An oriented walk double covering of a graph G
Factors of the physical environment associated with walking and bicycling
G. C. WANDA WENDEL-VOS; A. JANTINE SCHUIT; RAYMOND DE NIET; HENDRIEK C. BOSHUIZEN; WIM H. M. SARIS; DAAN KROMHOUT
2004-01-01
PURPOSE: The purpose of this study was to identify factors of the physical environment that may influence time spent on walking and bicycling. METHODS: Demographic factors and time spent on walking and bicycling (during leisure time and for commuting purposes) were assessed with a self-administered questionnaire. GIS databases were used to objectively measure the total square area of green space
Survival of branching random walks in random environment
Gantert, Nina
Survival of branching random walks in random environment Nina Gantert1 Sebastian M¨uller2 Serguei,marinav}@ime.unicamp.br, url: http://www.ime.usp.br/{popov,marinav} Abstract We study survival of nearest-neighbour branching random walks in random environment (BRWRE) on Z. A priori there are three different regimes of survival
Modular control of human walking: Adaptations to altered mechanical demands
altered. Walking simulations were generated that emulated human subjects who had their body weight and body weight was increased (decreased) and the module associated with providing forward propulsion), during tasks such stepping and kicking (Ivanenko et al., 2005) and when walking with body weight support
Elastic coupling of limb joints enables faster bipedal walking.
Dean, J C; Kuo, A D
2009-06-01
The passive dynamics of bipedal limbs alone are sufficient to produce a walking motion, without need for control. Humans augment these dynamics with muscles, actively coordinated to produce stable and economical walking. Present robots using passive dynamics walk much slower, perhaps because they lack elastic muscles that couple the joints. Elastic properties are well known to enhance running gaits, but their effect on walking has yet to be explored. Here we use a computational model of dynamic walking to show that elastic joint coupling can help to coordinate faster walking. In walking powered by trailing leg push-off, the model's speed is normally limited by a swing leg that moves too slowly to avoid stumbling. A uni-articular spring about the knee allows faster but uneconomical walking. A combination of uni-articular hip and knee springs can speed the legs for improved speed and economy, but not without the swing foot scuffing the ground. Bi-articular springs coupling the hips and knees can yield high economy and good ground clearance similar to humans. An important parameter is the knee-to-hip moment arm that greatly affects the existence and stability of gaits, and when selected appropriately can allow for a wide range of speeds. Elastic joint coupling may contribute to the economy and stability of human gait. PMID:18957360
Walk and Talk: An Intervention for Behaviorally Challenged Youths
ERIC Educational Resources Information Center
Doucette, Patricia A.
2004-01-01
This qualitative research explored the question: Do preadolescent and adolescent youths with behavioral challenges benefit from a multimodal intervention of walking outdoors while engaging in counseling? The objective of the Walk and Talk intervention is to help the youth feel better, explore alternative behavioral choices, and learn new coping…
Using Walk-Throughs to Gather Data for School Improvement
ERIC Educational Resources Information Center
Skretta, John
2007-01-01
This article discusses walk-throughs as a valuable source of instructional data for teachers and administrators. Data gathering and analysis can be a dynamic and exciting process when walk-throughs are incorporated into a school's improvement plan as an instructional snapshot. At Norris High School in Firth, Nebraska, the principal uses…
Walking Humanoids for Robotics Research Krister Wolff Peter Nordin
Fernandez, Thomas
. Microphones, cameras and touch sensors guide the robot. The imminent goals are to walk upright and to navigateWalking Humanoids for Robotics Research Krister Wolff Peter Nordin Dept. of Physical Resource, nordin}@fy.chalmers.se Abstract We present three humanoid robots aimed as platforms for research
Poincare-Map-Based Reinforcement Learning For Biped Walking
Zeglin, Garth
PoincarÂ´e-Map-Based Reinforcement Learning For Biped Walking Jun Morimoto1,2, Jun Nakanishi1,2, Gen trajectories. This decision is based on a learned model of the PoincarÂ´e map of the periodic walking pattern Learning; PoincarÂ´e map I. INTRODUCTION We propose a learning algorithm to acquire an appropri- ate biped