From a distance: Implications of spontaneous self-distancing for adaptive self-reflection

PubMed Central

Ayduk, Özlem; Kross, Ethan

2010-01-01

Although recent work experimental work indicates that self-distancing facilitates adaptive self-reflection, it remains unclear (a) whether spontaneously self-distancing leads to similar adaptive outcomes, (b) how spontaneous self-distancing relates to avoidance, and (c) how this strategy impacts interpersonal behavior. Three studies examined these issues demonstrating that the more participants spontaneously self-distanced while reflecting on negative memories, the less emotional (Studies 1–3) and cardiovascular (Study 2) reactivity they displayed in the short-term. Spontaneous self-distancing was also associated with lower emotional reactivity and intrusive ideation over time (Study 1). The negative association between spontaneous self-distancing and emotional reactivity was mediated by how participants construed their experience (i.e., less recounting relative to reconstruing) rather than avoidance (Studies 1–2). In addition, spontaneous self-distancing was associated with more problem-solving behavior and less reciprocation of negativity during conflicts among couples in ongoing relationships (Study 3). Although spontaneous self-distancing was empirically related to trait rumination, it explained unique variance in predicting key outcomes. PMID:20438226

Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances.

PubMed

Fort, Florian; Jouany, Claire; Cruz, Pablo

2015-01-01

Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance.

Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances

PubMed Central

Fort, Florian; Jouany, Claire; Cruz, Pablo

2015-01-01

Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance. PMID:25741353

Distance Education: A Consumer's Guide. What Distance Learners Need To Know.

ERIC Educational Resources Information Center

Western Interstate Commission for Higher Education, Boulder, CO. Western Cooperative for Educational Communications.

This pamphlet is intended to assist the consumer in making informed decisions when choosing between distance learning programs. Distance education and distance learners are defined. Included is advice on beginning a program search; choosing a school; accreditation; evaluating quality of electronically offered programs; evaluate non-accredited…

Lifelong Learning & Distance Higher Education. Perspectives on Distance Education

ERIC Educational Resources Information Center

McIntosh, Christopher, Ed.

2005-01-01

Reflecting a common objective of ensuring quality Education for All, this book is a joint initiative of UNESCO and COL and jointly published. Lifelong Learning in Distance Higher Education brings together a diverse group of experts from many countries. The book provides a clear picture of the challenges, problems and potential of distance higher…

Topological Distances Between Brain Networks

PubMed Central

Lee, Hyekyoung; Solo, Victor; Davidson, Richard J.; Pollak, Seth D.

2018-01-01

Many existing brain network distances are based on matrix norms. The element-wise differences may fail to capture underlying topological differences. Further, matrix norms are sensitive to outliers. A few extreme edge weights may severely affect the distance. Thus it is necessary to develop network distances that recognize topology. In this paper, we introduce Gromov-Hausdorff (GH) and Kolmogorov-Smirnov (KS) distances. GH-distance is often used in persistent homology based brain network models. The superior performance of KS-distance is contrasted against matrix norms and GH-distance in random network simulations with the ground truths. The KS-distance is then applied in characterizing the multimodal MRI and DTI study of maltreated children.

The Cost of Distance Education. IEC Broadsheets on Distance Learning No. 17.

ERIC Educational Resources Information Center

Perraton, Hilary

One of a series offering practical advice and information on distance teaching, this broadsheet first looks at the reasons for trying to measure distance teaching costs and the methodological and economic difficulties involved in such measurements. Broadcasting and print costs in distance teaching are discussed, and evidence about the costs of…

Distancing from experienced self: how global-versus-local perception affects estimation of psychological distance.

PubMed

Liberman, Nira; Förster, Jens

2009-08-01

In 4 studies, the authors examined the prediction derived from construal level theory (CLT) that higher level of perceptual construal would enhance estimated egocentric psychological distance. The authors primed participants with global perception, local perception, or both (the control condition). Relative to the control condition, global processing made participants estimate larger psychological distances in time (Study 1), space (Study 2), social distance (Study 3), and hypotheticality (Study 4). Local processing had the opposite effect. Consistent with CLT, all studies show that the effect of global-versus-local processing did emerge when participants estimated egocentric distances, which are distances from the experienced self in the here and now, but did not emerge with temporal distances not from now (Study 1), spatial distances not from here (Study 2), social distances not from the self (Study 3), or hypothetical events that did not involve altering an experienced reality (Study 4).

Distance learning perspectives.

PubMed

Pandza, Haris; Masic, Izet

2013-01-01

The development of modern technology and the Internet has enabled the explosive growth of distance learning. distance learning is a process that is increasingly present in the world. This is the field of education focused on educating students who are not physically present in the traditional classrooms or student's campus. described as a process where the source of information is separated from the students in space and time. If there are situations that require the physical presence of students, such as when a student is required to physically attend the exam, this is called a hybrid form of distance learning. This technology is increasingly used worldwide. The Internet has become the main communication channel for the development of distance learning.

Web-Based Communications, the Internet, and Distance Education. Readings in Distance Education, Number 7.

ERIC Educational Resources Information Center

Moore, Michael G., Ed.; Cozine, Geoffrey T., Ed.

This book brings together a selection of articles published in "The American Journal of Distance Education" that are related to Web-based delivery of distance education. Articles include: "Performance and Perceptions of Distance Learners in Cyberspace" (Peter Navarro and Judy Shoemaker); "Distance Education for Dentists: Improving the Quality of…

Has Distance Learning Become More Flexible? Reflections of a Distance Learning Student

ERIC Educational Resources Information Center

Thomas, Theda

2012-01-01

This paper provides insight into the way in which distance learning had changed over the past 30 years from the perspective of the author as a distance learning student. The question is then asked as to whether current practice is reducing flexibility for distance learning students? The paper starts with a discussion of flexible learning and the…

Going the Distance.

ERIC Educational Resources Information Center

Leno, Arthur J.

2003-01-01

Describes the development and implementation of the distance education program at Peirce College. This Internet-mediated distance learning program focuses on practical fields of study, drawing on the college's strengths in business administration, information technology, and paralegal studies. (SLD)

Making Distance Education Borderless.

ERIC Educational Resources Information Center

Srisa-An, Wichit

1997-01-01

Begins with a tribute to Professor G. Ram Reddy (founder of Indira Gandhi National Open University), then focuses on enhancing the role of open universities in providing borderless distance education. Highlights include the need for open distance-education; philosophy and vision; the distance teaching system; the role of information technology;…

Keeping one's distance: the influence of spatial distance cues on affect and evaluation.

PubMed

Williams, Lawrence E; Bargh, John A

2008-03-01

Current conceptualizations of psychological distance (e.g., construal-level theory) refer to the degree of overlap between the self and some other person, place, or point in time. We propose a complementary view in which perceptual and motor representations of physical distance influence people's thoughts and feelings without reference to the self, extending research and theory on the effects of distance into domains where construal-level theory is silent. Across four experiments, participants were primed with either spatial closeness or spatial distance by plotting an assigned set of points on a Cartesian coordinate plane. Compared with the closeness prime, the distance prime produced greater enjoyment of media depicting embarrassment (Study 1), less emotional distress from violent media (Study 2), lower estimates of the number of calories in unhealthy food (Study 3), and weaker reports of emotional attachments to family members and hometowns (Study 4). These results support a broader conceptualization of distance-mediated effects on judgment and affect.

Kinematic Distances: A Monte Carlo Method

NASA Astrophysics Data System (ADS)

Wenger, Trey V.; Balser, Dana S.; Anderson, L. D.; Bania, T. M.

2018-03-01

Distances to high-mass star-forming regions (HMSFRs) in the Milky Way are a crucial constraint on the structure of the Galaxy. Only kinematic distances are available for a majority of the HMSFRs in the Milky Way. Here, we compare the kinematic and parallax distances of 75 Galactic HMSFRs to assess the accuracy of kinematic distances. We derive the kinematic distances using three different methods: the traditional method using the Brand & Blitz rotation curve (Method A), the traditional method using the Reid et al. rotation curve and updated solar motion parameters (Method B), and a Monte Carlo technique (Method C). Methods B and C produce kinematic distances closest to the parallax distances, with median differences of 13% (0.43 {kpc}) and 17% (0.42 {kpc}), respectively. Except in the vicinity of the tangent point, the kinematic distance uncertainties derived by Method C are smaller than those of Methods A and B. In a large region of the Galaxy, the Method C kinematic distances constrain both the distances and the Galactocentric positions of HMSFRs more accurately than parallax distances. Beyond the tangent point along ℓ = 30°, for example, the Method C kinematic distance uncertainties reach a minimum of 10% of the parallax distance uncertainty at a distance of 14 {kpc}. We develop a prescription for deriving and applying the Method C kinematic distances and distance uncertainties. The code to generate the Method C kinematic distances is publicly available and may be utilized through an online tool.

Suppression of Systematic Errors of Electronic Distance Meters for Measurement of Short Distances

PubMed Central

Braun, Jaroslav; Štroner, Martin; Urban, Rudolf; Dvořáček, Filip

2015-01-01

In modern industrial geodesy, high demands are placed on the final accuracy, with expectations currently falling below 1 mm. The measurement methodology and surveying instruments used have to be adjusted to meet these stringent requirements, especially the total stations as the most often used instruments. A standard deviation of the measured distance is the accuracy parameter, commonly between 1 and 2 mm. This parameter is often discussed in conjunction with the determination of the real accuracy of measurements at very short distances (5–50 m) because it is generally known that this accuracy cannot be increased by simply repeating the measurement because a considerable part of the error is systematic. This article describes the detailed testing of electronic distance meters to determine the absolute size of their systematic errors, their stability over time, their repeatability and the real accuracy of their distance measurement. Twenty instruments (total stations) have been tested, and more than 60,000 distances in total were measured to determine the accuracy and precision parameters of the distance meters. Based on the experiments’ results, calibration procedures were designed, including a special correction function for each instrument, whose usage reduces the standard deviation of the measurement of distance by at least 50%. PMID:26258777

Suppression of Systematic Errors of Electronic Distance Meters for Measurement of Short Distances.

PubMed

Braun, Jaroslav; Štroner, Martin; Urban, Rudolf; Dvoček, Filip

2015-08-06

In modern industrial geodesy, high demands are placed on the final accuracy, with expectations currently falling below 1 mm. The measurement methodology and surveying instruments used have to be adjusted to meet these stringent requirements, especially the total stations as the most often used instruments. A standard deviation of the measured distance is the accuracy parameter, commonly between 1 and 2 mm. This parameter is often discussed in conjunction with the determination of the real accuracy of measurements at very short distances (5-50 m) because it is generally known that this accuracy cannot be increased by simply repeating the measurement because a considerable part of the error is systematic. This article describes the detailed testing of electronic distance meters to determine the absolute size of their systematic errors, their stability over time, their repeatability and the real accuracy of their distance measurement. Twenty instruments (total stations) have been tested, and more than 60,000 distances in total were measured to determine the accuracy and precision parameters of the distance meters. Based on the experiments' results, calibration procedures were designed, including a special correction function for each instrument, whose usage reduces the standard deviation of the measurement of distance by at least 50%.

Distance Education in Southern Africa Conference, 1987. Papers 2: Issues in Education and Distance Education.

ERIC Educational Resources Information Center

Adey, David, Comp.; And Others

Eighteen papers from the University of South Africa's Conference on Distance Education are presented on issues in education and distance education. They include: "Distance Education in Africa's Educational Development: The Case of Ghana" (Joe K. Ansere); "Distance Education: A Solution to the Economic Problems of Education in…

The semantic distance task: Quantifying semantic distance with semantic network path length.

PubMed

Kenett, Yoed N; Levi, Effi; Anaki, David; Faust, Miriam

2017-09-01

Semantic distance is a determining factor in cognitive processes, such as semantic priming, operating upon semantic memory. The main computational approach to compute semantic distance is through latent semantic analysis (LSA). However, objections have been raised against this approach, mainly in its failure at predicting semantic priming. We propose a novel approach to computing semantic distance, based on network science methodology. Path length in a semantic network represents the amount of steps needed to traverse from 1 word in the network to the other. We examine whether path length can be used as a measure of semantic distance, by investigating how path length affect performance in a semantic relatedness judgment task and recall from memory. Our results show a differential effect on performance: Up to 4 steps separating between word-pairs, participants exhibit an increase in reaction time (RT) and decrease in the percentage of word-pairs judged as related. From 4 steps onward, participants exhibit a significant decrease in RT and the word-pairs are dominantly judged as unrelated. Furthermore, we show that as path length between word-pairs increases, success in free- and cued-recall decreases. Finally, we demonstrate how our measure outperforms computational methods measuring semantic distance (LSA and positive pointwise mutual information) in predicting participants RT and subjective judgments of semantic strength. Thus, we provide a computational alternative to computing semantic distance. Furthermore, this approach addresses key issues in cognitive theory, namely the breadth of the spreading activation process and the effect of semantic distance on memory retrieval. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Reducing the distance: equity issues in distance learning in public education

NASA Astrophysics Data System (ADS)

Campbell, Patricia B.; Storo, Jennifer

1996-12-01

Distance learning and educational equity both began with an emphasis on access, on providing underserved students with an increased access to education. Today definitions of equity have gone beyond simple access to include equal or equivalent treatment and outcomes while definitions of underserved students have expanded to include girls, children of color, children with limited English proficiency and children with disabilities. At the same time the definition of distance learning has expanded to include new technologies, new audiences and new roles. Based on these new definitions and roles, the article raises a number of equity challenges for distance learning educators centering around who is taught, what is taught and how the teaching is done. To answer these challenges, a series of recommendations are suggested that educators can implement to make distance learning a leader in increasing educational equity for all students. The time to act is now.

Development of an in-fiber white-light interferometric distance sensor for absolute measurement of arbitrary small distances.

PubMed

Majumdar, Ayan; Huang, Haiying

2008-05-20

The fabrication, implementation, and evaluation of an in-fiber white-light interferometric distance sensor that is capable of measuring the absolute value of an arbitrary small distance are presented. Taking advantage of the mode-coupling effect of a long-period fiber grating, an additional cavity distance is added to the optical path difference of the distance sensor; therefore, it can generate a sufficient number of fringes for distance demodulation even if the free-space cavity distance is very small. It is experimentally verified that the distance sensor is capable of measuring small distances that are beyond the capability of a Fabry-Perot interferometric distance sensor.

Distance Magic-Type and Distance Antimagic-Type Labelings of Graphs

NASA Astrophysics Data System (ADS)

Freyberg, Bryan J.

Generally speaking, a distance magic-type labeling of a graph G of order n is a bijection l from the vertex set of the graph to the first n natural numbers or to the elements of a group of order n, with the property that the weight of each vertex is the same. The weight of a vertex x is defined as the sum (or appropriate group operation) of all the labels of vertices adjacent to x. If instead we require that all weights differ, then we refer to the labeling as a distance antimagic-type labeling. This idea can be generalized for directed graphs; the weight will take into consideration the direction of the arcs. In this manuscript, we provide new results for d-handicap labeling, a distance antimagic-type labeling, and introduce a new distance magic-type labeling called orientable Gamma-distance magic labeling. A d-handicap distance antimagic labeling (or just d-handicap labeling for short) of a graph G = ( V,E) of order n is a bijection l from V to the set {1,2,...,n} with induced weight function [special characters omitted]. such that l(xi) = i and the sequence of weights w(x 1),w(x2),...,w (xn) forms an arithmetic sequence with constant difference d at least 1. If a graph G admits a d-handicap labeling, we say G is a d-handicap graph. A d-handicap incomplete tournament, H(n,k,d ) is an incomplete tournament of n teams ranked with the first n natural numbers such that each team plays exactly k games and the strength of schedule of the ith ranked team is d more than the i + 1st ranked team. That is, strength of schedule increases arithmetically with strength of team. Constructing an H(n,k,d) is equivalent to finding a d-handicap labeling of a k-regular graph of order n.. In Chapter 2 we provide general constructions for every d for large classes of both n and k, providing breadfth and depth to the catalog of known H(n,k,d)'s. In Chapters 3 - 6, we introduce a new type of labeling called orientable Gamma-distance magic labeling. Let Gamma be an abelian group of order

Making Distance Visible: Assembling Nearness in an Online Distance Learning Programme

ERIC Educational Resources Information Center

Ross, Jen; Gallagher, Michael Sean; Macleod, Hamish

2013-01-01

Online distance learners are in a particularly complex relationship with the educational institutions they belong to (Bayne, Gallagher, & Lamb, 2012). For part-time distance students, arrivals and departures can be multiple and invisible as students take courses, take breaks, move into independent study phases of a programme, find work or…

Theoretical Principles of Distance Education.

ERIC Educational Resources Information Center

Keegan, Desmond, Ed.

This book contains the following papers examining the didactic, academic, analytic, philosophical, and technological underpinnings of distance education: "Introduction"; "Quality and Access in Distance Education: Theoretical Considerations" (D. Randy Garrison); "Theory of Transactional Distance" (Michael G. Moore);…

The Distance to M51

NASA Astrophysics Data System (ADS)

McQuinn, Kristen. B. W.; Skillman, Evan D.; Dolphin, Andrew E.; Berg, Danielle; Kennicutt, Robert

2016-07-01

Great investments of observing time have been dedicated to the study of nearby spiral galaxies with diverse goals ranging from understanding the star formation process to characterizing their dark matter distributions. Accurate distances are fundamental to interpreting observations of these galaxies, yet many of the best studied nearby galaxies have distances based on methods with relatively large uncertainties. We have started a program to derive accurate distances to these galaxies. Here we measure the distance to M51—the Whirlpool galaxy—from newly obtained Hubble Space Telescope optical imaging using the tip of the red giant branch method. We measure the distance modulus to be 8.58 ± 0.10 Mpc (statistical), corresponding to a distance modulus of 29.67 ± 0.02 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian Maximum Likelihood technique that reduces measurement uncertainties. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Distance learning in academic health education.

PubMed

Mattheos, N; Schittek, M; Attström, R; Lyon, H C

2001-05-01

Distance learning is an apparent alternative to traditional methods in education of health care professionals. Non-interactive distance learning, interactive courses and virtual learning environments exist as three different generations in distance learning, each with unique methodologies, strengths and potential. Different methodologies have been recommended for distance learning, varying from a didactic approach to a problem-based learning procedure. Accreditation, teamwork and personal contact between the tutors and the students during a course provided by distance learning are recommended as motivating factors in order to enhance the effectiveness of the learning. Numerous assessment methods for distance learning courses have been proposed. However, few studies report adequate tests for the effectiveness of the distance-learning environment. Available information indicates that distance learning may significantly decrease the cost of academic health education at all levels. Furthermore, such courses can provide education to students and professionals not accessible by traditional methods. Distance learning applications still lack the support of a solid theoretical framework and are only evaluated to a limited extent. Cases reported so far tend to present enthusiastic results, while more carefully-controlled studies suggest a cautious attitude towards distance learning. There is a vital need for research evidence to identify the factors of importance and variables involved in distance learning. The effectiveness of distance learning courses, especially in relation to traditional teaching methods, must therefore be further investigated.

Estimating rupture distances without a rupture

USGS Publications Warehouse

Thompson, Eric M.; Worden, Charles

2017-01-01

Most ground motion prediction equations (GMPEs) require distances that are defined relative to a rupture model, such as the distance to the surface projection of the rupture (RJB) or the closest distance to the rupture plane (RRUP). There are a number of situations in which GMPEs are used where it is either necessary or advantageous to derive rupture distances from point-source distance metrics, such as hypocentral (RHYP) or epicentral (REPI) distance. For ShakeMap, it is necessary to provide an estimate of the shaking levels for events without rupture models, and before rupture models are available for events that eventually do have rupture models. In probabilistic seismic hazard analysis, it is often convenient to use point-source distances for gridded seismicity sources, particularly if a preferred orientation is unknown. This avoids the computationally cumbersome task of computing rupture-based distances for virtual rupture planes across all strikes and dips for each source. We derive average rupture distances conditioned on REPI, magnitude, and (optionally) back azimuth, for a variety of assumed seismological constraints. Additionally, we derive adjustment factors for GMPE standard deviations that reflect the added uncertainty in the ground motion estimation when point-source distances are used to estimate rupture distances.

Designing mark-recapture studies to reduce effects of distance weighting on movement distance distributions of stream fishes

USGS Publications Warehouse

Albanese, B.; Angermeier, P.L.; Gowan, C.

2003-01-01

Mark-recapture studies generate biased, or distance-weighted, movement data because short distances are sampled more frequently than long distances. Using models and field data, we determined how study design affects distance weighting and the movement distributions of stream fishes. We first modeled distance weighting as a function of recapture section length in an unbranching stream. The addition of an unsampled tributary to one of these models substantially increased distance weighting by decreasing the percentage of upstream distances that were sampled. Similarly, the presence of multiple tributaries in the field study resulted in severe bias. However, increasing recapture section length strongly affected distance weighting in both the model and the field study, producing a zone where the number of fish moving could be estimated with little bias. Subsampled data from the field study indicated that longer median (three of three species) and maximum distances (two of three species) can be detected by increasing the length of the recapture section. The effect was extreme for bluehead chub Nocomis leptocephalus, a highly mobile species, which exhibited a longer median distance (133 m versus 60 m), a longer maximum distance (1,144 m versus 708 m), and a distance distribution that differed in shape when the full (4,123-m recapture section) and subsampled (1,978-m recapture section) data sets were compared. Correction factors that adjust the observed number of movements to undersampled distances upwards and those to oversampled distances downwards could not mitigate the distance weighting imposed by the shorter recapture section. Future studies should identify the spatial scale over which movements can be accurately measured before data are collected. Increasing recapture section length a priori is far superior to using post hoc correction factors to reduce the influence of distance weighting on observed distributions. Implementing these strategies will be especially

Managing Time, Workload and Costs in Distance Education: Findings from a Literature Review of "Distances et Médiations des Savoirs" (Formerly "Distances et Savoirs")

ERIC Educational Resources Information Center

Moeglin, Pierre; Vidal, Martine

2015-01-01

The purpose of this review, spanning over 12 years of publication of "Distances et Médiations des Savoirs" ("DMS"), formerly "Distance et Savoirs" ("DMS") (2003-2014), is guided by the question why and how French-speaking researchers addressed the issues of time, workload and costs in distance learning, and…

Distance Education in the Health Sciences. Readings in Distance Education, Number 8.

ERIC Educational Resources Information Center

Moore, Michael G. Ed.; Savrock, Joseph T., Ed.

This document contains 17 papers on distance education in the health sciences. The following papers are included: "Preface: Distance Education in the Health Professions: A Collection of Research" (Michael G. Moore); "A Historical Overview of Telecommunications in the Health Care Industry" (Joseph S. Anderson); "Distance…

Distance Teacher Education in Pakistan

ERIC Educational Resources Information Center

Jumani, Nabi Bux; Zai, Zafar Iqbal Yousuf

2009-01-01

Distance education means instruction in which the instructor and student are separated by distance and interact through the assistance of communication technology. Distance education changes the learning relationship from the common, centralized school model to a more decentralized, flexible model. It also reverses social dynamics by bringing…

Connecting long distance: semantic distance in analogical reasoning modulates frontopolar cortex activity.

PubMed

Green, Adam E; Kraemer, David J M; Fugelsang, Jonathan A; Gray, Jeremy R; Dunbar, Kevin N

2010-01-01

Solving problems often requires seeing new connections between concepts or events that seemed unrelated at first. Innovative solutions of this kind depend on analogical reasoning, a relational reasoning process that involves mapping similarities between concepts. Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key characteristic of the kind of analogical mapping that can support innovation (i.e., identifying similarities across greater semantic distance reveals connections that support more innovative solutions and models). However, the neural substrates of semantically distant analogical mapping are not well understood. Here, we used functional magnetic resonance imaging (fMRI) to measure brain activity during an analogical reasoning task, in which we parametrically varied the semantic distance between the items in the analogies. Semantic distance was derived quantitatively from latent semantic analysis. Across 23 participants, activity in an a priori region of interest (ROI) in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. This ROI was centered on a functional peak that we previously associated with analogical mapping. To our knowledge, these data represent a first empirical characterization of how the brain mediates semantically distant analogical mapping.

Estimating Distances from Parallaxes. III. Distances of Two Million Stars in the Gaia DR1 Catalogue

NASA Astrophysics Data System (ADS)

Astraatmadja, Tri L.; Bailer-Jones, Coryn A. L.

2016-12-01

We infer distances and their asymmetric uncertainties for two million stars using the parallaxes published in the Gaia DR1 (GDR1) catalogue. We do this with two distance priors: A minimalist, isotropic prior assuming an exponentially decreasing space density with increasing distance, and an anisotropic prior derived from the observability of stars in a Milky Way model. We validate our results by comparing our distance estimates for 105 Cepheids which have more precise, independently estimated distances. For this sample we find that the Milky Way prior performs better (the rms of the scaled residuals is 0.40) than the exponentially decreasing space density prior (rms is 0.57), although for distances beyond 2 kpc the Milky Way prior performs worse, with a bias in the scaled residuals of -0.36 (versus -0.07 for the exponentially decreasing space density prior). We do not attempt to include the photometric data in GDR1 due to the lack of reliable color information. Our distance catalog is available at http://www.mpia.de/homes/calj/tgas_distances/main.html as well as at CDS. This should only be used to give individual distances. Combining data or testing models should be done with the original parallaxes, and attention paid to correlated and systematic uncertainties.

The Two Modes of Distance Education.

ERIC Educational Resources Information Center

Keegan, Desmond

1998-01-01

Discusses two models of distance-education, group-based versus individual-based. Highlights include group-based distance education for full-time and part-time students; individual-based distance education with pre-prepared materials and without pre-prepared materials; and distance education management and research. (LRW)

Cosmic distance duality and cosmic transparency

NASA Astrophysics Data System (ADS)

Nair, Remya; Jhingan, Sanjay; Jain, Deepak

2012-12-01

We compare distance measurements obtained from two distance indicators, Supernovae observations (standard candles) and Baryon acoustic oscillation data (standard rulers). The Union2 sample of supernovae with BAO data from SDSS, 6dFGS and the latest BOSS and WiggleZ surveys is used in search for deviations from the distance duality relation. We find that the supernovae are brighter than expected from BAO measurements. The luminosity distances tend to be smaller then expected from angular diameter distance estimates as also found in earlier works on distance duality, but the trend is not statistically significant. This further constrains the cosmic transparency.

Perceptual distance and the moon illusion.

PubMed

Kaufman, Lloyd; Vassiliades, Vassias; Noble, Richard; Alexander, Robert; Kaufman, James; Edlund, Stefan

2007-01-01

The elevated moon usually appears smaller than the horizon moon of equal angular size. This is the moon illusion. Distance cues may enable the perceptual system to place the horizon moon at an effectively greater distance than the elevated moon, thus making it appear as larger. This explanation is related to the size-distance invariance hypothesis. However, the larger horizon moon is usually judged as closer than the smaller zenith moon. A bias to expect an apparently large object to be closer than a smaller object may account for this conflict. We designed experiments to determine if unbiased sensitivity to illusory differences in the size and distance of the moon (as measured by d') is consistent with SDIH. A moon above a 'terrain' was compared in both distance and size to an infinitely distant moon in empty space (the reduction moon). At a short distance the terrain moon was adjudged as both closer and smaller than the reduction moon. But these differences could not be detected at somewhat greater distances. At still greater distances the terrain moon was perceived as both more distant and larger than the reduction moon. The distances at which these transitions occurred were essentially the same for both distance and size discrimination tasks, thus supporting SDIH.

Language distance and tree reconstruction

NASA Astrophysics Data System (ADS)

Petroni, Filippo; Serva, Maurizio

2008-08-01

Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others.

Stereoscopic distance perception

NASA Technical Reports Server (NTRS)

Foley, John M.

1989-01-01

Limited cue, open-loop tasks in which a human observer indicates distances or relations among distances are discussed. By open-loop tasks, it is meant tasks in which the observer gets no feedback as to the accuracy of the responses. What happens when cues are added and when the loop is closed are considered. The implications of this research for the effectiveness of visual displays is discussed. Errors in visual distance tasks do not necessarily mean that the percept is in error. The error could arise in transformations that intervene between the percept and the response. It is argued that the percept is in error. It is also argued that there exist post-perceptual transformations that may contribute to the error or be modified by feedback to correct for the error.

2007-08 Distance Education Report

ERIC Educational Resources Information Center

Nevada System of Higher Education, 2008

2008-01-01

This report focuses on distance education within the Nevada System of Higher Education (NSHE) for the 2007-08 academic year and provides documentation of the substantial growth of distance education within all colleges and universities. Distance education is a field of continuous improvement and change, and NSHE institutions are constantly…

Interactive Distance Learning in Connecticut.

ERIC Educational Resources Information Center

Pietras, Jesse John; Murphy, Robert J.

This paper provides an overview of distance learning activities in Connecticut and addresses the feasibility of such activities. Distance education programs have evolved from the one dimensional electronic mail systems to the use of sophisticated digital fiber networks. The Middlesex Distance Learning Consortium has developed a long-range plan to…

The Semantic Distance Task: Quantifying Semantic Distance with Semantic Network Path Length

ERIC Educational Resources Information Center

Kenett, Yoed N.; Levi, Effi; Anaki, David; Faust, Miriam

2017-01-01

Semantic distance is a determining factor in cognitive processes, such as semantic priming, operating upon semantic memory. The main computational approach to compute semantic distance is through latent semantic analysis (LSA). However, objections have been raised against this approach, mainly in its failure at predicting semantic priming. We…

Deciphering the Distance between Distance Education and Working Professionals in Difficult Geographies

ERIC Educational Resources Information Center

Pandey, Jatin; Singh, Manjari

2015-01-01

This study investigates the factors that draw working professionals towards distance education programs, and the factors that sustain their distance education experience. The study is conducted in difficult terrains of Uttarakhand, a hilly state in India which helps us investigate the phenomenon in difficult geographies. Through interviews of ten…

Minimum distance classification in remote sensing

NASA Technical Reports Server (NTRS)

Wacker, A. G.; Landgrebe, D. A.

1972-01-01

The utilization of minimum distance classification methods in remote sensing problems, such as crop species identification, is considered. Literature concerning both minimum distance classification problems and distance measures is reviewed. Experimental results are presented for several examples. The objective of these examples is to: (a) compare the sample classification accuracy of a minimum distance classifier, with the vector classification accuracy of a maximum likelihood classifier, and (b) compare the accuracy of a parametric minimum distance classifier with that of a nonparametric one. Results show the minimum distance classifier performance is 5% to 10% better than that of the maximum likelihood classifier. The nonparametric classifier is only slightly better than the parametric version.

Machine learning enhanced optical distance sensor

NASA Astrophysics Data System (ADS)

Amin, M. Junaid; Riza, N. A.

2018-01-01

Presented for the first time is a machine learning enhanced optical distance sensor. The distance sensor is based on our previously demonstrated distance measurement technique that uses an Electronically Controlled Variable Focus Lens (ECVFL) with a laser source to illuminate a target plane with a controlled optical beam spot. This spot with varying spot sizes is viewed by an off-axis camera and the spot size data is processed to compute the distance. In particular, proposed and demonstrated in this paper is the use of a regularized polynomial regression based supervised machine learning algorithm to enhance the accuracy of the operational sensor. The algorithm uses the acquired features and corresponding labels that are the actual target distance values to train a machine learning model. The optimized training model is trained over a 1000 mm (or 1 m) experimental target distance range. Using the machine learning algorithm produces a training set and testing set distance measurement errors of <0.8 mm and <2.2 mm, respectively. The test measurement error is at least a factor of 4 improvement over our prior sensor demonstration without the use of machine learning. Applications for the proposed sensor include industrial scenario distance sensing where target material specific training models can be generated to realize low <1% measurement error distance measurements.

The visual perception of distance ratios outdoors.

PubMed

Norman, J Farley; Adkins, Olivia C; Dowell, Catherine J; Shain, Lindsey M; Hoyng, Stevie C; Kinnard, Jonathan D

2017-05-01

We conducted an experiment to evaluate the ability of 32 younger and older adults to visually perceive distances in an outdoor setting. On any given trial, the observers viewed 2 environmental distances and were required to estimate the distance ratio-the length of the (usually) larger distance relative to that of the shorter. The stimulus distance ratios ranged from 1.0 (the stimulus distances were identical) to 8.0 (1 distance interval was 8.0 times longer than the other). The stimulus distances were presented within a 26 m × 60 m portion of a grassy field. The observers were able to reliably estimate the stimulus distance ratios: The overall Pearson r correlation coefficient relating the judged and actual distance ratios was 0.762. Fifty-eight percent of the variance in the observers' perceived distance ratios could thus be accounted for by variations in the actual stimulus ratios. About half of the observers significantly underestimated the distance ratios, while the judgments of the remainder were essentially accurate. Significant modulatory effects of sex and age occurred, such that the male observers' judgments were the most precise, while those of the older males were the most accurate.

Improved Iris Recognition through Fusion of Hamming Distance and Fragile Bit Distance.

PubMed

Hollingsworth, Karen P; Bowyer, Kevin W; Flynn, Patrick J

2011-12-01

The most common iris biometric algorithm represents the texture of an iris using a binary iris code. Not all bits in an iris code are equally consistent. A bit is deemed fragile if its value changes across iris codes created from different images of the same iris. Previous research has shown that iris recognition performance can be improved by masking these fragile bits. Rather than ignoring fragile bits completely, we consider what beneficial information can be obtained from the fragile bits. We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metric, called the fragile bit distance, which quantitatively measures the coincidence of the fragile bit patterns in two iris codes. We find that score fusion of fragile bit distance and Hamming distance works better for recognition than Hamming distance alone. To our knowledge, this is the first and only work to use the coincidence of fragile bit locations to improve the accuracy of matches.

Going the Distance: A National Distance Learning Initiative.

ERIC Educational Resources Information Center

Dubois, Jaques R.

1996-01-01

Going the Distance is a Public Broadcasting Service project through which over 130 colleges and universities are offering telecourses for adults seeking associate degrees. It is the beginning of a global learning community. (SK)

On the inversion-indel distance

PubMed Central

2013-01-01

Background The inversion distance, that is the distance between two unichromosomal genomes with the same content allowing only inversions of DNA segments, can be computed thanks to a pioneering approach of Hannenhalli and Pevzner in 1995. In 2000, El-Mabrouk extended the inversion model to allow the comparison of unichromosomal genomes with unequal contents, thus insertions and deletions of DNA segments besides inversions. However, an exact algorithm was presented only for the case in which we have insertions alone and no deletion (or vice versa), while a heuristic was provided for the symmetric case, that allows both insertions and deletions and is called the inversion-indel distance. In 2005, Yancopoulos, Attie and Friedberg started a new branch of research by introducing the generic double cut and join (DCJ) operation, that can represent several genome rearrangements (including inversions). Among others, the DCJ model gave rise to two important results. First, it has been shown that the inversion distance can be computed in a simpler way with the help of the DCJ operation. Second, the DCJ operation originated the DCJ-indel distance, that allows the comparison of genomes with unequal contents, considering DCJ, insertions and deletions, and can be computed in linear time. Results In the present work we put these two results together to solve an open problem, showing that, when the graph that represents the relation between the two compared genomes has no bad components, the inversion-indel distance is equal to the DCJ-indel distance. We also give a lower and an upper bound for the inversion-indel distance in the presence of bad components. PMID:24564182

Measuring genetic distances between breeds: use of some distances in various short term evolution models

PubMed Central

Laval, Guillaume; SanCristobal, Magali; Chevalet, Claude

2002-01-01

Many works demonstrate the benefits of using highly polymorphic markers such as microsatellites in order to measure the genetic diversity between closely related breeds. But it is sometimes difficult to decide which genetic distance should be used. In this paper we review the behaviour of the main distances encountered in the literature in various divergence models. In the first part, we consider that breeds are populations in which the assumption of equilibrium between drift and mutation is verified. In this case some interesting distances can be expressed as a function of divergence time, t, and therefore can be used to construct phylogenies. Distances based on allele size distribution (such as (δμ)2 and derived distances), taking a mutation model of microsatellites, the Stepwise Mutation Model, specifically into account, exhibit large variance and therefore should not be used to accurately infer phylogeny of closely related breeds. In the last section, we will consider that breeds are small populations and that the divergence times between them are too small to consider that the observed diversity is due to mutations: divergence is mainly due to genetic drift. Expectation and variance of distances were calculated as a function of the Wright-Malécot inbreeding coefficient, F. Computer simulations performed under this divergence model show that the Reynolds distance [57]is the best method for very closely related breeds. PMID:12270106

KINEMATIC DISTANCES OF GALACTIC PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, A. Y.; Tian, W. W.; Zhu, H.

2016-03-15

We construct H i absorption spectra for 18 planetary nebulae (PNs) and their background sources using data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNs, among which 15 objects’ kinematic distances are obtained for the first time. The distance uncertainties of 13 PNs range from 10% to 50%, which is a significant improvement with uncertainties of a factor of two or three smaller than most previous distance measurements. We confirm that PN G030.2−00.1 is not a PN because of its large distance found here.

The minimum distance approach to classification

NASA Technical Reports Server (NTRS)

Wacker, A. G.; Landgrebe, D. A.

1971-01-01

The work to advance the state-of-the-art of miminum distance classification is reportd. This is accomplished through a combination of theoretical and comprehensive experimental investigations based on multispectral scanner data. A survey of the literature for suitable distance measures was conducted and the results of this survey are presented. It is shown that minimum distance classification, using density estimators and Kullback-Leibler numbers as the distance measure, is equivalent to a form of maximum likelihood sample classification. It is also shown that for the parametric case, minimum distance classification is equivalent to nearest neighbor classification in the parameter space.

From language identification to language distance

NASA Astrophysics Data System (ADS)

Gamallo, Pablo; Pichel, José Ramom; Alegria, Iñaki

2017-10-01

In this paper, we define two quantitative distances to measure how far apart two languages are. The distance measure that we have identified as more accurate is based on the perplexity of n-gram models extracted from text corpora. An experiment to compare forty-four European languages has been performed. For this purpose, we computed the distances for all the possible language pairs and built a network whose nodes are languages and edges are distances. The network we have built on the basis of linguistic distances represents the current map of similarities and divergences among the main languages of Europe.

Distance and Cable Length Measurement System

PubMed Central

Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay

2009-01-01

A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169

Distance Education in Entwicklungslandern.

ERIC Educational Resources Information Center

German Foundation for International Development, Bonn (West Germany).

Seminar and conference reports and working papers on distance education of adults, which reflect the experiences of many countries, are presented. Contents include the draft report of the 1979 International Seminar on Distance Education held in Addis Ababa, Ethiopia, which was jointly sponsored by the United Nations Economic Commission for Africa…

Biomechanics of Distance Running.

ERIC Educational Resources Information Center

Cavanagh, Peter R., Ed.

Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

The unassigned distance geometry problem

DOE PAGES

Duxbury, P. M.; Granlund, L.; Gujarathi, S. R.; ...

2015-11-19

Studies of distance geometry problems (DGP) have focused on cases where the vertices at the ends of all or most of the given distances are known or assigned, which we call assigned distance geometry problems (aDGPs). In this contribution we consider the unassigned distance geometry problem (uDGP) where the vertices associated with a given distance are unknown, so the graph structure has to be discovered. uDGPs arises when attempting to find the atomic structure of molecules and nanoparticles using X-ray or neutron diffraction data from non-crystalline materials. Rigidity theory provides a useful foundation for both aDGPs and uDGPs, though itmore » is restricted to generic realizations of graphs, and key results are summarized. Conditions for unique realization are discussed for aDGP and uDGP cases, build-up algorithms for both cases are described and experimental results for uDGP are presented.« less

Traversing State Boundaries with Distance Education: The Tri-State Agricultural Distance Delivery Alliance.

ERIC Educational Resources Information Center

Anderson, Erik T.; Makus, Larry; Fanno, Wayne; Swan, Mike

The Tri-State Agricultural Distance Delivery Alliance (TADDA) is a new distance education consortium. The three land grant universities in the Pacific Northwest (the University of Idaho, Oregon State University, and Washington State University) developed TADDA in cooperation with Eastern Oregon University and four of the region's community…

Education at a Distance.

ERIC Educational Resources Information Center

Maffett, Sheryl Price

2007-01-01

Distance learning has been around since the old "course in a box" correspondence classes, but with the advent of sophisticated online course management systems, learning at a distance is contributing to a major paradigm shift in higher education. That shift includes applying corporate concepts to education--students, for example, are "consumers,"…

Revised Distances to 21 Supernova Remnants

NASA Astrophysics Data System (ADS)

Ranasinghe, S.; Leahy, D. A.

2018-05-01

We carry out a comprehensive study of H I 21 cm line observations and 13CO line observations of 21 supernova remnants (SNRs). The aim of the study is to search for H I absorption features to obtain kinematic distances in a consistent manner. The 21 SNRs are in the region of sky covered by the Very Large Array Galactic Plane Survey (H I 21 cm observations) and Galactic Ring Survey (13CO line observations). We obtain revised distances for 10 SNRs based on new evidence in the H I and 13CO observations. We revise distances for the other 11 SNRs based on an updated rotation curve and new error analysis. The mean change in distance for the 21 SNRs is ≃25%, i.e., a change of 1.5 kpc compared to a mean distance for the sample of 6.4 kpc. This has a significant impact on interpretation of the physical state of these SNRs. For example, using a Sedov model, age and explosion energy scale as the square of distance, and inferred ISM density scales as distance.

A Cognitively Grounded Measure of Pronunciation Distance

PubMed Central

Wieling, Martijn; Nerbonne, John; Bloem, Jelke; Gooskens, Charlotte; Heeringa, Wilbert; Baayen, R. Harald

2014-01-01

In this study we develop pronunciation distances based on naive discriminative learning (NDL). Measures of pronunciation distance are used in several subfields of linguistics, including psycholinguistics, dialectology and typology. In contrast to the commonly used Levenshtein algorithm, NDL is grounded in cognitive theory of competitive reinforcement learning and is able to generate asymmetrical pronunciation distances. In a first study, we validated the NDL-based pronunciation distances by comparing them to a large set of native-likeness ratings given by native American English speakers when presented with accented English speech. In a second study, the NDL-based pronunciation distances were validated on the basis of perceptual dialect distances of Norwegian speakers. Results indicated that the NDL-based pronunciation distances matched perceptual distances reasonably well with correlations ranging between 0.7 and 0.8. While the correlations were comparable to those obtained using the Levenshtein distance, the NDL-based approach is more flexible as it is also able to incorporate acoustic information other than sound segments. PMID:24416119

Distance Education: An Overview.

ERIC Educational Resources Information Center

Batey, Anne; Cowell, Richard N.

Distance education is a current "catch-all" phrase for any form of instruction in which the learner is linked to an educational institution and is formally enrolled, but instruction does not necessarily have to be delivered to or from an official school site. Distance education can provide equity and increase the quality of educational…

Sleeping distance in wild wolf packs

USGS Publications Warehouse

Knick, S.T.; Mech, L.D.

1980-01-01

Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

Graph distance for complex networks

NASA Astrophysics Data System (ADS)

Shimada, Yutaka; Hirata, Yoshito; Ikeguchi, Tohru; Aihara, Kazuyuki

2016-10-01

Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions.

The distances of the Galactic Novae

NASA Astrophysics Data System (ADS)

Ozdonmez, Aykut; Guver, Tolga; Cabrera-Lavers, Antonio; Ak, Tansel

2016-07-01

Using location of the RC stars on the CMDs obtained from the UKIDSS, VISTA and 2MASS photometry, we have derived the reddening-distance relations towards each Galactic nova for which at least one independent reddening measurement exists. We were able to determine the distances of 72 Galactic novae and set lower limits on the distances of 45 systems. The reddening curves of the systems are presented. These curves can be also used to estimate reddening or the distance of any source, whose location is close to the position of the nova in our sample. The distance measurement method in our study can be easily applicable to any source, especially for ones that concentrated along the Galactic plane.

Optimal flight initiation distance.

PubMed

Cooper, William E; Frederick, William G

2007-01-07

Decisions regarding flight initiation distance have received scant theoretical attention. A graphical model by Ydenberg and Dill (1986. The economics of fleeing from predators. Adv. Stud. Behav. 16, 229-249) that has guided research for the past 20 years specifies when escape begins. In the model, a prey detects a predator, monitors its approach until costs of escape and of remaining are equal, and then flees. The distance between predator and prey when escape is initiated (approach distance = flight initiation distance) occurs where decreasing cost of remaining and increasing cost of fleeing intersect. We argue that prey fleeing as predicted cannot maximize fitness because the best prey can do is break even during an encounter. We develop two optimality models, one applying when all expected future contribution to fitness (residual reproductive value) is lost if the prey dies, the other when any fitness gained (increase in expected RRV) during the encounter is retained after death. Both models predict optimal flight initiation distance from initial expected fitness, benefits obtainable during encounters, costs of escaping, and probability of being killed. Predictions match extensively verified predictions of Ydenberg and Dill's (1986) model. Our main conclusion is that optimality models are preferable to break-even models because they permit fitness maximization, offer many new testable predictions, and allow assessment of prey decisions in many naturally occurring situations through modification of benefit, escape cost, and risk functions.

Distance Education in Papua New Guinea.

ERIC Educational Resources Information Center

Avalos, Beatrice, Ed.

1991-01-01

The theme of this special double serial issue is "Distance Education in Papua New Guinea." The following articles are featured: (1) "Distance Education in Papua New Guinea" (John Lynch); (2) "Distance Education in Papua New Guinea: Context, Issues and Prospects" (Michael Crossley and Richard Guy); (3) "Distance…

Distance-limited perpendicular distance sampling for coarse woody debris: theory and field results

Treesearch

Mark J. Ducey; Micheal S. Williams; Jeffrey H. Gove; Steven Roberge; Robert S. Kenning

2013-01-01

Coarse woody debris (CWD) has been identified as an important component in many forest ecosystem processes. Perpendicular distance sampling (PDS) is one of the several efficient new methods that have been proposed for CWD inventory. One drawback of PDS is that the maximum search distance can be very large, especially if CWD diameters are large or the volume factor...

Calibrating Reach Distance to Visual Targets

ERIC Educational Resources Information Center

Mon-Williams, Mark; Bingham, Geoffrey P.

2007-01-01

The authors investigated the calibration of reach distance by gradually distorting the haptic feedback obtained when participants grasped visible target objects. The authors found that the modified relationship between visually specified distance and reach distance could be captured by a straight-line mapping function. Thus, the relation could be…

Rough Way for Academics: Distance Education

ERIC Educational Resources Information Center

Gursul, Fatih

2010-01-01

This study aims to compare the academics' perceptions about face to face and distance education, beside finding out the contributions of distance education to them, difficulties they experience in synchronous and asynchronous distance education environments and suggestions for possible solutions of the existing problems. The sample consists of 52…

Tidewater Community College Distance Learning Report.

ERIC Educational Resources Information Center

Tidewater Community Coll., Norfolk, VA.

This study of distance learning at Tidewater Community College (TCC) was conducted to determine enrollment patterns, retention, and success in distance learning courses and student perceptions. Distance learning was defined as students enrolled in one of three modes of course delivery: telecourse, online, and compressed video. The time frame for…

The Distancing Question in Online Education

ERIC Educational Resources Information Center

Russell, Glenn

2005-01-01

Intellectuals in many fields have long argued that, as the distance between people increases, the possibility for genuine empathy between them decreases. In this article, the author argues that distancing has as-yet unexplored pragmatic consequences in online education. As he has argued elsewhere (Russell 2004), distancing can be understood as…

Estimating Distances from Parallaxes. II. Performance of Bayesian Distance Estimators on a Gaia-like Catalogue

NASA Astrophysics Data System (ADS)

Astraatmadja, Tri L.; Bailer-Jones, Coryn A. L.

2016-12-01

Estimating a distance by inverting a parallax is only valid in the absence of noise. As most stars in the Gaia catalog will have non-negligible fractional parallax errors, we must treat distance estimation as a constrained inference problem. Here we investigate the performance of various priors for estimating distances, using a simulated Gaia catalog of one billion stars. We use three minimalist, isotropic priors, as well an anisotropic prior derived from the observability of stars in a Milky Way model. The two priors that assume a uniform distribution of stars—either in distance or in space density—give poor results: The root mean square fractional distance error, {f}{rms}, grows far in excess of 100% once the fractional parallax error, {f}{true}, is larger than 0.1. A prior assuming an exponentially decreasing space density with increasing distance performs well once its single parameter—the scale length— has been set to an appropriate value: {f}{rms} is roughly equal to {f}{true} for {f}{true}\\lt 0.4, yet does not increase further as {f}{true} increases up to to 1.0. The Milky Way prior performs well except toward the Galactic center, due to a mismatch with the (simulated) data. Such mismatches will be inevitable (and remain unknown) in real applications, and can produce large errors. We therefore suggest adopting the simpler exponentially decreasing space density prior, which is also less time-consuming to compute. Including Gaia photometry improves the distance estimation significantly for both the Milky Way and exponentially decreasing space density prior, yet doing so requires additional assumptions about the physical nature of stars.

A distance education in undergraduate dietetic education.

PubMed

Benton-King, Carrie; Webb, Derek F; Holmes, ZoeAnn

2005-01-01

Distance education is an exploding phenomenon that allows people to pursue higher education on their own time, at a pace that meets their needs, in locations where there are no colleges and universities, or where there is not a desired program of study. This study examined the use of distance education in undergraduate dietetic education programs and the opportunities for obtaining an undergraduate degree in dietetics solely via distance education. A survey was sent to all directors (n = 279) of undergraduate programs accredited/approved by the Commission on Accreditation for Dietetics Education to determine the current status and projected future use of distance education in their institutions' on-campus programs. The survey had a 54% response rate. Approximately 32% (n = 150) of undergraduate dietetics programs offer distance education courses in some format. Institutions that offer nondietetics distance education courses were more likely to offer dietetics distance education courses. The most common distance education format utilized in dietetics was 100% Internet courses (48%). The most common distance education dietetics course offered was a basic or introductory nutrition course (31%). From the data of courses offered, or permitted to be transferred, it would not be possible for a student to complete an undergraduate degree in dietetics solely via distance education methodologies at the time this study was conducted.

How Haptic Size Sensations Improve Distance Perception

PubMed Central

Battaglia, Peter W.; Kersten, Daniel; Schrater, Paul R.

2011-01-01

Determining distances to objects is one of the most ubiquitous perceptual tasks in everyday life. Nevertheless, it is challenging because the information from a single image confounds object size and distance. Though our brains frequently judge distances accurately, the underlying computations employed by the brain are not well understood. Our work illuminates these computions by formulating a family of probabilistic models that encompass a variety of distinct hypotheses about distance and size perception. We compare these models' predictions to a set of human distance judgments in an interception experiment and use Bayesian analysis tools to quantitatively select the best hypothesis on the basis of its explanatory power and robustness over experimental data. The central question is: whether, and how, human distance perception incorporates size cues to improve accuracy. Our conclusions are: 1) humans incorporate haptic object size sensations for distance perception, 2) the incorporation of haptic sensations is suboptimal given their reliability, 3) humans use environmentally accurate size and distance priors, 4) distance judgments are produced by perceptual “posterior sampling”. In addition, we compared our model's estimated sensory and motor noise parameters with previously reported measurements in the perceptual literature and found good correspondence between them. Taken together, these results represent a major step forward in establishing the computational underpinnings of human distance perception and the role of size information. PMID:21738457

Cepheids Geometrical Distances Using Space Interferometry

NASA Astrophysics Data System (ADS)

Marengo, M.; Karovska, M.; Sasselov, D. D.; Sanchez, M.

2004-05-01

A space based interferometer with a sub-milliarcsecond resolution in the UV-optical will provide a new avenue for the calibration of primary distance indicators with unprecedented accuracy, by allowing very accurate and stable measurements of Cepheids pulsation amplitudes at wavelengths not accessible from the ground. Sasselov & Karovska (1994) have shown that interferometers allow very accurate measurements of Cepheids distances by using a ``geometric'' variant of the Baade-Wesselink method. This method has been succesfully applied to derive distances and radii of nearby Cepheids using ground-based near-IR and optical interferometers, within a 15% accuracy level. Our study shows that the main source of error in these measurements is due to the perturbing effects of the Earth atmosphere, which is the limiting factor in the interferometer stability. A space interferometer will not suffer from this intrinsic limitations, and can potentially lead to improve astronomical distance measurements by an order of magnitude in precision. We discuss here the technical requirements that a space based facility will need to carry out this project, allowing distance measurements within a few percent accuracy level. We will finally discuss how a sub-milliarcsecond resolution will allow the direct distance determination for hundreds of galactic sources, and provide a substantial improvement in the zero-point of the Cepheid distance scale.

Perspectives of Research on Distance Education.

ERIC Educational Resources Information Center

Holmberg, Borje

The history of research on distance education was studied. Major research done on distance education in such diverse areas as the United States, Venezuela, and Europe was analyzed. It was discovered that the earliest attempts to develop theories of distance education were mainly concerned with identifying its very concept. Like most educational…

Quality Assurance in Distance Learning Libraries

ERIC Educational Resources Information Center

Tripathi, Manorama; Jeevan, V. K. J.

2009-01-01

Purpose: The paper aims to study how the present distance learning libraries can improve upon their existing services and introduce new ones to enhance quality of services to distance learners. Design/methodology/approach: The paper includes a review of literature on quality assurance in open and distance education in general and student support…

Analysing designed experiments in distance sampling

Treesearch

Stephen T. Buckland; Robin E. Russell; Brett G. Dickson; Victoria A. Saab; Donal N. Gorman; William M. Block

2009-01-01

Distance sampling is a survey technique for estimating the abundance or density of wild animal populations. Detection probabilities of animals inherently differ by species, age class, habitats, or sex. By incorporating the change in an observer's ability to detect a particular class of animals as a function of distance, distance sampling leads to density estimates...

Antigenic Distance Measurements for Seasonal Influenza Vaccine Selection

PubMed Central

Cai, Zhipeng; Zhang, Tong; Wan, Xiu-Feng

2011-01-01

Influenza vaccination is one of the major options to counteract the effects of influenza diseases. Selection of an effective vaccine strain is the key to the success of an effective vaccination program since vaccine protection can only be achieved when the selected influenza vaccine strain matches the antigenic variants causing future outbreaks. Identification of an antigenic variant is the first step to determine whether vaccine strain needs to be updated. Antigenic distance derived from immunological assays, such as hemagglutination inhibition, is commonly used to measure the antigenic closeness between circulating strains and the current influenza vaccine strain. Thus, consensus on an explicit and robust antigenic distance measurement is critical in influenza surveillance. Based on the current seasonal influenza surveillance procedure, we propose and compare three antigenic distance measurements, including Average antigenic distance (A-distance), Mutual antigenic distance (M-distance), and Largest antigenic distance (L-distance). With the assistance of influenza antigenic cartography, our simulation results demonstrated that M-distance is a robust influenza antigenic distance measurement. Experimental results on both simulation and seasonal influenza surveillance data demonstrate that M-distance can be effectively utilized in influenza vaccine strain selection. PMID:22063385

Permutation-invariant distance between atomic configurations

NASA Astrophysics Data System (ADS)

Ferré, Grégoire; Maillet, Jean-Bernard; Stoltz, Gabriel

2015-09-01

We present a permutation-invariant distance between atomic configurations, defined through a functional representation of atomic positions. This distance enables us to directly compare different atomic environments with an arbitrary number of particles, without going through a space of reduced dimensionality (i.e., fingerprints) as an intermediate step. Moreover, this distance is naturally invariant through permutations of atoms, avoiding the time consuming associated minimization required by other common criteria (like the root mean square distance). Finally, the invariance through global rotations is accounted for by a minimization procedure in the space of rotations solved by Monte Carlo simulated annealing. A formal framework is also introduced, showing that the distance we propose verifies the property of a metric on the space of atomic configurations. Two examples of applications are proposed. The first one consists in evaluating faithfulness of some fingerprints (or descriptors), i.e., their capacity to represent the structural information of a configuration. The second application concerns structural analysis, where our distance proves to be efficient in discriminating different local structures and even classifying their degree of similarity.

Problems in Defining the Field of Distance Education.

ERIC Educational Resources Information Center

Keegan, Desmond

1988-01-01

This discussion of definitions of distance education responds to previous articles attempting to define the field. Topics discussed include distance education versus conventional education; group-based distance education; differences between open learning and distance education; and criteria to define distance education. (13 references) (LRW)

The Gould’s Belt Distances Survey (GOBELINS). III. The Distance to the Serpens/Aquila Molecular Complex

NASA Astrophysics Data System (ADS)

Ortiz-León, Gisela N.; Dzib, Sergio A.; Kounkel, Marina A.; Loinard, Laurent; Mioduszewski, Amy J.; Rodríguez, Luis F.; Torres, Rosa M.; Pech, Gerardo; Rivera, Juana L.; Hartmann, Lee; Boden, Andrew F.; Evans, Neal J., II; Briceño, Cesar; Tobin, John J.; Galli, Phillip A. B.

2017-01-01

We report on new distances and proper motions to seven stars across the Serpens/Aquila complex. The observations were obtained as part of the Gould’s Belt Distances Survey (GOBELINS) project between 2013 September and 2016 April with the Very Long Baseline Array (VLBA). One of our targets is the proto-Herbig AeBe object EC 95, which is a binary system embedded in the Serpens Core. For this system, we combined the GOBELINS observations with previous VLBA data to cover a total period of 8 years, and derive the orbital elements and an updated source distance. The individual distances to sources in the complex are fully consistent with each other, and the mean value corresponds to a distance of 436.0 ± 9.2 pc for the Serpens/W40 complex. Given this new evidence, we argue that Serpens Main, W40, and Serpens South are physically associated and form a single cloud structure.

Modern Geometric Methods of Distance Determination

NASA Astrophysics Data System (ADS)

Thévenin, Frédéric; Falanga, Maurizio; Kuo, Cheng Yu; Pietrzyński, Grzegorz; Yamaguchi, Masaki

2017-11-01

Building a 3D picture of the Universe at any distance is one of the major challenges in astronomy, from the nearby Solar System to distant Quasars and galaxies. This goal has forced astronomers to develop techniques to estimate or to measure the distance of point sources on the sky. While most distance estimates used since the beginning of the 20th century are based on our understanding of the physics of objects of the Universe: stars, galaxies, QSOs, the direct measures of distances are based on the geometric methods as developed in ancient Greece: the parallax, which has been applied to stars for the first time in the mid-19th century. In this review, different techniques of geometrical astrometry applied to various stellar and cosmological (Megamaser) objects are presented. They consist in parallax measurements from ground based equipment or from space missions, but also in the study of binary stars or, as we shall see, of binary systems in distant extragalactic sources using radio telescopes. The Gaia mission will be presented in the context of stellar physics and galactic structure, because this key space mission in astronomy will bring a breakthrough in our understanding of stars, galaxies and the Universe in their nature and evolution with time. Measuring the distance to a star is the starting point for an unbiased description of its physics and the estimate of its fundamental parameters like its age. Applying these studies to candles such as the Cepheids will impact our large distance studies and calibration of other candles. The text is constructed as follows: introducing the parallax concept and measurement, we shall present briefly the Gaia satellite which will be the future base catalogue of stellar astronomy in the near future. Cepheids will be discussed just after to demonstrate the state of the art in distance measurements in the Universe with these variable stars, with the objective of 1% of error in distances that could be applied to our closest

Multimedia Equipment for Distance Education.

ERIC Educational Resources Information Center

Schiller, Scott S.

1993-01-01

Discusses the use of multimedia equipment for distance education. Topics addressed include use of the Internet; distance learning for educators; and cable television and/or fiber optics, including interactive television and satellite technology. A sidebar lists online and telecommunications providers. (LRW)

Distance Measurements In X-Ray Pictures

NASA Astrophysics Data System (ADS)

Forsgren, Per-Ola

1987-10-01

In this paper, a measurement method for the distance between binary objects will be presented. It has been developed for a specific purpose, the evaluation of rheumatic disease, but should be useful also in other applications. It is based on a distance map in the area between binary objects. A skeleton is extracted from the distance map by searching for local maxima. The distance measure is based on the average of skelton points in a defined measurement area. An objective criterion for selection of measurement points on the skeleton is proposed. Preliminary results indicate that good repeatability is attained.

Cognitive Styles and Distance Education.

ERIC Educational Resources Information Center

Liu, Yuliang; Ginther, Dean

1999-01-01

Considers how to adapt the design of distance education to students' cognitive styles. Discusses cognitive styles, including field dependence versus independence, holistic-analytic, sensory preference, hemispheric preferences, and Kolb's Learning Style Model; and the characteristics of distance education, including technology. (Contains 92…

Gd(III)-Gd(III) EPR distance measurements--the range of accessible distances and the impact of zero field splitting.

PubMed

Dalaloyan, Arina; Qi, Mian; Ruthstein, Sharon; Vega, Shimon; Godt, Adelheid; Feintuch, Akiva; Goldfarb, Daniella

2015-07-28

Gd(III) complexes have emerged as spin labels for distance determination in biomolecules through double-electron-electron resonance (DEER) measurements at high fields. For data analysis, the standard approach developed for a pair of weakly coupled spins with S = 1/2 was applied, ignoring the actual properties of Gd(III) ions, i.e. S = 7/2 and ZFS (zero field splitting) ≠ 0. The present study reports on a careful investigation on the consequences of this approach, together with the range of distances accessible by DEER with Gd(III) complexes as spin labels. The experiments were performed on a series of specifically designed and synthesized Gd-rulers (Gd-PyMTA-spacer-Gd-PyMTA) covering Gd-Gd distances of 2-8 nm. These were dissolved in D2O-glycerol-d8 (0.03-0.10 mM solutions) which is the solvent used for the corresponding experiments on biomolecules. Q- and W-band DEER measurements, followed by data analysis using the standard data analysis approach, used for S = 1/2 pairs gave the distance-distribution curves, of which the absolute maxima agreed very well with the expected distances. However, in the case of the short distances of 2.1 and 2.9 nm, the distance distributions revealed additional peaks. These are a consequence of neglecting the pseudo-secular term in the dipolar Hamiltonian during the data analysis, as is outlined in a theoretical treatment. At distances of 3.4 nm and above, disregarding the pseudo-secular term leads to a broadening of a maximum of 0.4 nm of the distance-distribution curves at half height. Overall, the distances of up to 8.3 nm were determined, and the long evolution time of 16 μs at 10 K indicates that a distance of up to 9.4 nm can be accessed. A large distribution of the ZFS parameter, D, as is found for most Gd(III) complexes in a frozen solution, is crucial for the application of Gd(III) complexes as spin labels for distance determination via Gd(III)-Gd(III) DEER, especially for short distances. The larger ZFS of Gd-PyMTA, in

Going the Distance: Are There Common Factors in High Performance Distance Learning? Research Report.

ERIC Educational Resources Information Center

Hawksley, Rosemary; Owen, Jane

Common factors among high-performing distance learning (DL) programs were examined through case studies at 9 further education colleges and 2 nonsector organizations in the United Kingdom and a backup survey of a sample of 50 distance learners at 5 of the colleges. The study methodology incorporated numerous principles of process benchmarking. The…

Joint learning of labels and distance metric.

PubMed

Liu, Bo; Wang, Meng; Hong, Richang; Zha, Zhengjun; Hua, Xian-Sheng

2010-06-01

Machine learning algorithms frequently suffer from the insufficiency of training data and the usage of inappropriate distance metric. In this paper, we propose a joint learning of labels and distance metric (JLLDM) approach, which is able to simultaneously address the two difficulties. In comparison with the existing semi-supervised learning and distance metric learning methods that focus only on label prediction or distance metric construction, the JLLDM algorithm optimizes the labels of unlabeled samples and a Mahalanobis distance metric in a unified scheme. The advantage of JLLDM is multifold: 1) the problem of training data insufficiency can be tackled; 2) a good distance metric can be constructed with only very few training samples; and 3) no radius parameter is needed since the algorithm automatically determines the scale of the metric. Extensive experiments are conducted to compare the JLLDM approach with different semi-supervised learning and distance metric learning methods, and empirical results demonstrate its effectiveness.

Telecommunications, Internationalism, and Distance Education.

ERIC Educational Resources Information Center

Moore, Michael G.

1988-01-01

Discussion of the role of telecommunications in distance education focuses on teleconference networks and international cooperation. Highlights include the TELECON VII Distance Learning Conference, the use of teleconferencing by corporations for continuing education and training, and questions to be addressed concerning the future potential of…

Determining accurate distances to nearby galaxies

NASA Astrophysics Data System (ADS)

Bonanos, Alceste Zoe

2005-11-01

Determining accurate distances to nearby or distant galaxies is a very simple conceptually, yet complicated in practice, task. Presently, distances to nearby galaxies are only known to an accuracy of 10-15%. The current anchor galaxy of the extragalactic distance scale is the Large Magellanic Cloud, which has large (10-15%) systematic uncertainties associated with it, because of its morphology, its non-uniform reddening and the unknown metallicity dependence of the Cepheid period-luminosity relation. This work aims to determine accurate distances to some nearby galaxies, and subsequently help reduce the error in the extragalactic distance scale and the Hubble constant H 0 . In particular, this work presents the first distance determination of the DIRECT Project to M33 with detached eclipsing binaries. DIRECT aims to obtain a new anchor galaxy for the extragalactic distance scale by measuring direct, accurate (to 5%) distances to two Local Group galaxies, M31 and M33, with detached eclipsing binaries. It involves a massive variability survey of these galaxies and subsequent photometric and spectroscopic follow-up of the detached binaries discovered. In this work, I also present a catalog of variable stars discovered in one of the DIRECT fields, M31Y, which includes 41 eclipsing binaries. Additionally, we derive the distance to the Draco Dwarf Spheroidal galaxy, with ~100 RR Lyrae found in our first CCD variability study of this galaxy. A "hybrid" method of discovering Cepheids with ground-based telescopes is described next. It involves applying the image subtraction technique on the images obtained from ground-based telescopes and then following them up with the Hubble Space Telescope to derive Cepheid period-luminosity distances. By re-analyzing ESO Very Large Telescope data on M83 (NGC 5236), we demonstrate that this method is much more powerful for detecting variability, especially in crowded fields. I finally present photometry for the Wolf-Rayet binary WR 20a

The ideal subject distance for passport pictures.

PubMed

Verhoff, Marcel A; Witzel, Carsten; Kreutz, Kerstin; Ramsthaler, Frank

2008-07-04

In an age of global combat against terrorism, the recognition and identification of people on document images is of increasing significance. Experiments and calculations have shown that the camera-to-subject distance - not the focal length of the lens - can have a significant effect on facial proportions. Modern passport pictures should be able to function as a reference image for automatic and manual picture comparisons. This requires a defined subject distance. It is completely unclear which subject distance, in the taking of passport photographs, is ideal for the recognition of the actual person. We show here that the camera-to-subject distance that is perceived as ideal is dependent on the face being photographed, even if the distance of 2m was most frequently preferred. So far the problem of the ideal camera-to-subject distance for faces has only been approached through technical calculations. We have, for the first time, answered this question experimentally with a double-blind experiment. Even if there is apparently no ideal camera-to-subject distance valid for every face, 2m can be proposed as ideal for the taking of passport pictures. The first step would actually be the determination of a camera-to-subject distance for the taking of passport pictures within the standards. From an anthropological point of view it would be interesting to find out which facial features allow the preference of a shorter camera-to-subject distance and which allow the preference of a longer camera-to-subject distance.

Distance Delivery of Vocational Education Technologies and Planning Matrixes.

ERIC Educational Resources Information Center

Norenberg, Curtis D.; Lundblad, Larry

This document presents a general review of distance education as it currently pertains to secondary, postsecondary, and adult education. Chapter I discusses the general concepts of distance education. It addresses the nature of distance education and distance delivery, the distance learner, the distance instructor, and distance education learning…

A new statistical distance scale for planetary nebulae

NASA Astrophysics Data System (ADS)

Ali, Alaa; Ismail, H. A.; Alsolami, Z.

2015-05-01

In the first part of the present article we discuss the consistency among different individual distance methods of Galactic planetary nebulae, while in the second part we develop a new statistical distance scale based on a calibrating sample of well determined distances. A set composed of 315 planetary nebulae with individual distances are extracted from the literature. Inspecting the data set indicates that the accuracy of distances is varying among different individual methods and also among different sources where the same individual method was applied. Therefore, we derive a reliable weighted mean distance for each object by considering the influence of the distance error and the weight of each individual method. The results reveal that the discussed individual methods are consistent with each other, except the gravity method that produces higher distances compared to other individual methods. From the initial data set, we construct a standard calibrating sample consists of 82 objects. This sample is restricted only to the objects with distances determined from at least two different individual methods, except few objects with trusted distances determined from the trigonometric, spectroscopic, and cluster membership methods. In addition to the well determined distances for this sample, it shows a lot of advantages over that used in the prior distance scales. This sample is used to recalibrate the mass-radius and radio surface brightness temperature-radius relationships. An average error of ˜30 % is estimated for the new distance scale. The newly distance scale is compared with the most widely used statistical scales in literature, where the results show that it is roughly similar to the majority of them within ˜±20 % difference. Furthermore, the new scale yields a weighted mean distance to the Galactic center of 7.6±1.35 kpc, which in good agreement with the very recent measure of Malkin 2013.

Machine Learning with Distances

DTIC Science & Technology

2015-02-16

of training class-wise densities p(x|y) to test input density p′(x). For the fitting of qπ to p ′, we may use the Kullback - Leibler (KL...Problems of Information Transmission, 23(9):95–101, 1987. [103] S. Kullback and R. A. Leibler . On information and sufficiency. The Annals of ...distributions. The Kullback - Leibler (KL) distance is the de-facto standard distance measure in statis- tics and machine learning, because

Research in Distance Education: 2. Revised Papers from the Research in Distance Education Seminar (2nd, Geelong, Victoria, Australia, 1991).

ERIC Educational Resources Information Center

Evans, Terry, Ed.; Juler, Philip, Ed.

Nineteen papers concerning various aspects of distance education and distance education research are presented in this document. The papers are: (1) "Introduction, Celebrating Difference in Research in Distance Education" (Terry Evans); (2) "Discourse or Discord? A Dilemma of Distance Education" (Philip Juler); (3)…

Distance Learning: Practice and Dilemmas

ERIC Educational Resources Information Center

Tatkovic, Nevenka; Sehanovic, Jusuf; Ruzic, Maja

2006-01-01

In accordance with the European processes of integrated and homogeneous education, the paper presents the essential viewpoints and questions covering the establishment and development of "distance learning" (DL) in Republic of Croatia. It starts from the advantages of distance learning versus traditional education taking into account…

Geometric comparison of popular mixture-model distances.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Scott A.

2010-09-01

Statistical Latent Dirichlet Analysis produces mixture model data that are geometrically equivalent to points lying on a regular simplex in moderate to high dimensions. Numerous other statistical models and techniques also produce data in this geometric category, even though the meaning of the axes and coordinate values differs significantly. A distance function is used to further analyze these points, for example to cluster them. Several different distance functions are popular amongst statisticians; which distance function is chosen is usually driven by the historical preference of the application domain, information-theoretic considerations, or by the desirability of the clustering results. Relatively littlemore » consideration is usually given to how distance functions geometrically transform data, or the distances algebraic properties. Here we take a look at these issues, in the hope of providing complementary insight and inspiring further geometric thought. Several popular distances, {chi}{sup 2}, Jensen - Shannon divergence, and the square of the Hellinger distance, are shown to be nearly equivalent; in terms of functional forms after transformations, factorizations, and series expansions; and in terms of the shape and proximity of constant-value contours. This is somewhat surprising given that their original functional forms look quite different. Cosine similarity is the square of the Euclidean distance, and a similar geometric relationship is shown with Hellinger and another cosine. We suggest a geodesic variation of Hellinger. The square-root projection that arises in Hellinger distance is briefly compared to standard normalization for Euclidean distance. We include detailed derivations of some ratio and difference bounds for illustrative purposes. We provide some constructions that nearly achieve the worst-case ratios, relevant for contours.« less

Adult Education at a Distance.

ERIC Educational Resources Information Center

Gaudet, Alphonse

This document, which examines the use of educational technologies for distance education for adults in Canada, consists of five narrative sections and a bibliography. The first section introduces the topic and the document's objectives (to describe those technologies used in Canadian adult distance education, paying particular attention to those…

Distance Education. [SITE 2001 Section].

ERIC Educational Resources Information Center

Fuller, Frank, Ed.; McBride, Ron, Ed.

This document contains the papers on distance education from the SITE (Society for Information Technology & Teacher Education) 2001 conference. Topics covered include: the distance education degree program for the Master of Mathematics with a teaching option at Texas A&M University; the evolution of online learning; Internet-based distance…

Construal-Level Theory of Psychological Distance

PubMed Central

Trope, Yaacov; Liberman, Nira

2011-01-01

People are capable of thinking about the future, the past, remote locations, another person’s perspective, and counterfactual alternatives. Without denying the uniqueness of each process, it is proposed that they constitute different forms of traversing psychological distance. Psychological distance is egocentric: Its reference point is the self in the here and now, and the different ways in which an object might be removed from that point—in time, in space, in social distance, and in hypotheticality—constitute different distance dimensions. Transcending the self in the here and now entails mental construal, and the farther removed an object is from direct experience, the higher (more abstract) the level of construal of that object. Supporting this analysis, research shows (a) that the various distances are cognitively related to each other, (b) that they similarly influence and are influenced by level of mental construal, and (c) that they similarly affect prediction, preference, and action. PMID:20438233

Long distance quantum teleportation

NASA Astrophysics Data System (ADS)

Xia, Xiu-Xiu; Sun, Qi-Chao; Zhang, Qiang; Pan, Jian-Wei

2018-01-01

Quantum teleportation is a core protocol in quantum information science. Besides revealing the fascinating feature of quantum entanglement, quantum teleportation provides an ultimate way to distribute quantum state over extremely long distance, which is crucial for global quantum communication and future quantum networks. In this review, we focus on the long distance quantum teleportation experiments, especially those employing photonic qubits. From the viewpoint of real-world application, both the technical advantages and disadvantages of these experiments are discussed.

The history of soil erosion: Interpreting historical sources, buried soils and colluvial sediments as archives of past soil erosion and human-environment interactions in the Longue Durée

NASA Astrophysics Data System (ADS)

Dotterweich, Markus

2015-04-01

of human-environment interactions in the Longue Durée.

Making Distance Learning E.R.O.T.I.C.: Applying Interpretation Principles to Distance Learning

ERIC Educational Resources Information Center

Ross, Anne; Siepen, Greg; O'Connor, Sue

2003-01-01

Distance learners are self-directed learners traditionally taught via study books, collections of readings, and exercises to test understanding of learning packages. Despite advances in e-Learning environments and computer-based teaching interfaces, distance learners still lack opportunities to participate in exercises and debates available to…

Distance Learning and Non-Formal Education: Existing Trends and New Possibilities of Distance Learning Experiences.

ERIC Educational Resources Information Center

Romi, Shlomo

2000-01-01

Reviews the characteristics of non-formal education as expressed in various academic-theoretical definitions, presents the links in this field to distance learning, and recommends future directions for exploring distance learning in non-formal education. Discusses the use of information and communication technology and considers problems with…

Virtual Bioinformatics Distance Learning Suite

ERIC Educational Resources Information Center

Tolvanen, Martti; Vihinen, Mauno

2004-01-01

Distance learning as a computer-aided concept allows students to take courses from anywhere at any time. In bioinformatics, computers are needed to collect, store, process, and analyze massive amounts of biological and biomedical data. We have applied the concept of distance learning in virtual bioinformatics to provide university course material…

Perceived distance during golf putting.

PubMed

Hasegawa, Yumiko; Koyama, Satoshi; Inomata, Kimihiro

2013-12-01

This study examined the effect of anxiety states on the relationship between golf-putting distance and performance in an environment requiring high movement accuracy. Twenty-three amateur golfers attempted 15 putts at each of three putting distances, 1.25, 1.50, and 1.75m, under conditions characterized by both control demands and pressure. All attempts were recorded, and kinematic features were analyzed. Under conditions involving an audience and a monetary reward, the mean score on the State-Trait Anxiety Inventory Y-1 and the mean heart rate increased by 14 points and 11bpm, respectively. We grouped participants on an a posteriori basis using the median split. The backswing of high-anxiety performers shortened, the downswing speed declined, and the relative time to peak club-head velocity changed when putting under pressure from 1.25m. In contrast, no change in backswing or relative time to peak velocity was observed in low-anxiety performers, although impact velocity increased under this condition. These results indicate that the degree to which both low- and high-anxiety golfers were anxious about failure affected motor control at the 1.25-m distance, suggesting that a distortion in perceived distance may result from the interaction between putting distance and anxiety related to failure during golf putting. Copyright © 2013 Elsevier B.V. All rights reserved.

Astronomical Distance Determination in the Space Age. Secondary Distance Indicators

NASA Astrophysics Data System (ADS)

Czerny, Bożena; Beaton, Rachael; Bejger, Michał; Cackett, Edward; Dall'Ora, Massimo; Holanda, R. F. L.; Jensen, Joseph B.; Jha, Saurabh W.; Lusso, Elisabeta; Minezaki, Takeo; Risaliti, Guido; Salaris, Maurizio; Toonen, Silvia; Yoshii, Yuzuru

2018-02-01

The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations.

Distance versus near visual acuity in amblyopia

PubMed Central

Christoff, Alex; Repka, Michael X.; Kaminski, Brett M.; Holmes, Jonathan M.; Ch, B

2011-01-01

Purpose There are conflicting reports about whether distance and near visual acuity are similar in eyes with amblyopia. The purpose of this study is to compare monocular distance visual acuity with near visual acuity in amblyopic eyes of children. Methods Subjects 2 to 6 years of age were evaluated in a randomized trial of amblyopia therapy for moderate amblyopia (20/40 to 20/80) due to anisometropia, strabismus, or both. Prior to initiating the protocol-prescribed therapy, subjects had best-corrected visual acuity measured with standardized protocols at 3 meters and 0.4 meters using single-surrounded HOTV optotypes. Results A total of 129 subjects were included. The mean amblyopic eye visual acuity was similar at distance and near (mean, 0.45 logMAR at distance versus 0.45 logMAR at near; mean difference, +0.00, 95% CI, −0.03 to 0.03). Of the 129 subjects, 86 (67%) tested within one line at distance and near, 19 (15%) tested more than one logMAR line better at distance, and 24 (19%) tested more than one logMAR line better at near. The mean visual acuity difference between distance and near did not differ by cause of amblyopia, age, or spherical equivalent refractive error. Conclusions We found no systematic difference between distance and near visual acuity in 2- to 6-year-old children with moderate amblyopia associated with strabismus and/or anisometropia. Individual differences between distance and near visual acuity are likely due to test–retest variability. PMID:21907115

Distance Education. Overview. ERIC Digest No. 44.

ERIC Educational Resources Information Center

Naylor, Michele

Technological advancement has both facilitated and necessitated the development of distance education programming. In developing nations, distance education is often used to provide traditional education like that usually available in conventional institutions in the Western world. Whereas distance education in the Soviet Union focuses on…

Passion at a Distance

NASA Astrophysics Data System (ADS)

Howard, Don

In 1984, Abner Shimony invented the expression, "passion at a distance," to characterize the distinctive relationship of two entangled quantum mechanical systems [1]. It is neither the local causality of pushes, pulls, and central forces familiar from classical mechanics and electrodynamics, nor the non-local causality of instantaneous or just superluminal action at a distance that would spell trouble for relativity theory. This mode of connection of entangled systems has them feeling one another's presence and properties enough to ensure the strong correlations revealed in the Bell experiments, correlations that undergird everything from superfluidity and superconductivity to quantum computing and quantum teleportation, but not in a way that permits direct control of one by manipulation of the other. Intended to echo Aristotle's distinguishing of "potentiality" from "actuality" as different senses of "being," Shimony's "passion at a distance" is all about tendency and propensity, not the concreteness whose misplacement in realm of the physical was lamented by Alfred North Whitehead.

Instructional Design for Distance Training.

ERIC Educational Resources Information Center

Carter, John F.

Distance education, especially in the form of correspondence study, is not a new phenomenon, but the success of the British Open University has given it a new image. Distance education programs have been developed to respond to a variety of societal and educational situations for which traditional classroom-based approaches are less feasible. They…

Blogging for the Distance Librarian

ERIC Educational Resources Information Center

Pival, Paul R.

2005-01-01

Based on user lookups, "Merriam-Webster Online "proclaimed "Blog" the word of the year for 2004. Distance librarianship, until mid-way through 2004, was a subject that was underrepresented in the blogosphere. The inception of a blog called "The Distant Librarian: Comments on the World of Distance Librarianship" is chronicled in this article, along…

Quality Content in Distance Education

ERIC Educational Resources Information Center

Yildiz, Ezgi Pelin; Isman, Aytekin

2016-01-01

In parallel with technological advances in today's world of education activities can be conducted without the constraints of time and space. One of the most important of these activities is distance education. The success of the distance education is possible with content quality. The proliferation of e-learning environment has brought a need for…

The numerical distance effect is task dependent.

PubMed

Goldfarb, Liat; Henik, Avishai; Rubinsten, Orly; Bloch-David, Yafit; Gertner, Limor

2011-11-01

Number comparison tasks produce a distance effect e.g., Moyer & Landauer (Nature 215: 1519-1520, 1967). It has been suggested that this effect supports the existence of semantic mental representations of numbers. In a matching task, a distance effect also appears, which suggests that the effect has an automatic semantic component. Recently, Cohen (Psychonomic Bulletin & Review 16: 332-336, 2009) suggested that in both automatic and intentional tasks, the distance effect might reflect not a semantic number representation, but a physical similarity between digits. The present article (1) compares the distance effect in the automatic matching task with that in the intentional number comparison task and suggests that, in the latter, the distance effect does include an additional semantic component; and (2) indicates that the distance effect in the standard automatic matching task is questionable and that its appearance in previous matching tasks was based on the specific analysis and design that were applied.

Internet-Based Distance Learning in Higher Education.

ERIC Educational Resources Information Center

Hofmann, Donald W.

2002-01-01

Suggests that the effectiveness of Internet-based distance learning has increased with its increased popularity. Looks at the differences between the effectiveness of Internet-based distance learning and traditional methods. Indicates that distance learning is more effective because of the necessity for students to become active learners.…

Effectiveness of Mobile Learning in Distance Education

ERIC Educational Resources Information Center

Yousuf, Muhammad Imran

2007-01-01

The main aim of this research is to better understand and measure students' attitudes and perceptions towards the importance of mobile learning in distance education. Results of this survey clearly indicate that facilitating mobile learning can improve the entire distance education by enhancing ways of communication among distance learners, tutors…

Distance Education in Asia and the Pacific.

ERIC Educational Resources Information Center

Cahill, Bruce, Ed.

1985-01-01

Issues related to the use of distance education are discussed in this bulletin, which also summarizes the status of distance education in 26 countries of Asia and the Pacific. Section 1 contains a rationale for distance education and points out possibilities offered by advances in communication technologies. Section 2 gives country-by-country…

Generalising Ward's Method for Use with Manhattan Distances.

PubMed

Strauss, Trudie; von Maltitz, Michael Johan

2017-01-01

The claim that Ward's linkage algorithm in hierarchical clustering is limited to use with Euclidean distances is investigated. In this paper, Ward's clustering algorithm is generalised to use with l1 norm or Manhattan distances. We argue that the generalisation of Ward's linkage method to incorporate Manhattan distances is theoretically sound and provide an example of where this method outperforms the method using Euclidean distances. As an application, we perform statistical analyses on languages using methods normally applied to biology and genetic classification. We aim to quantify differences in character traits between languages and use a statistical language signature based on relative bi-gram (sequence of two letters) frequencies to calculate a distance matrix between 32 Indo-European languages. We then use Ward's method of hierarchical clustering to classify the languages, using the Euclidean distance and the Manhattan distance. Results obtained from using the different distance metrics are compared to show that the Ward's algorithm characteristic of minimising intra-cluster variation and maximising inter-cluster variation is not violated when using the Manhattan metric.

Distance-responsive genes found in dancing honey bees.

PubMed

Sen Sarma, M; Rodriguez-Zas, S L; Gernat, T; Nguyen, T; Newman, T; Robinson, G E

2010-10-01

We report that regions of the honey bee brain involved in visual processing and learning and memory show a specific genomic response to distance information. These results were obtained with an established method that separates effects of perceived distance from effects of actual distance flown. Individuals forced to shift from a short to perceived long distance to reach a feeding site showed gene expression differences in the optic lobes and mushroom bodies relative to individuals that continued to perceive a short distance, even though they all flew the same distance. Bioinformatic analyses suggest that the genomic response to distance information involves learning and memory systems associated with well-known signaling pathways, synaptic remodeling, transcription factors and protein metabolism. By showing distance-sensitive brain gene expression, our findings also significantly extend the emerging paradigm of the genome as a dynamic regulator of behavior, that is particularly responsive to stimuli important in social life. © 2010 The Authors. Genes, Brain and Behavior © 2010 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

E-Learning and Distance Education in Nigeria

ERIC Educational Resources Information Center

Ajadi, Timothy Olugbenga; Salawu, Ibrahim Olatunde; Adeoye, Femi Adetunji

2008-01-01

This paper discusses the relevance of e-learning in the position of distance education in Nigeria. It commences by discussing the meaning of e-learning and distance education. It also discusses the historical background of distance education in Nigeria as well as the operations of National Open University of Nigeria (NOUN) as the first federal…

Distance Training in the European Union. ZIFF Papiere 96.

ERIC Educational Resources Information Center

Keegan, Desmond

A study examined distance training in the European Union (EU) countries. First, recent literature on the following topics was reviewed: technology-supported learning, flexible and distance learning, development of open distance learning, and teleconferencing and distance learning. Next, enrollments and trends in distance learning in the EU as a…

On the Nature of Distance Education.

ERIC Educational Resources Information Center

Baath, John A.

1981-01-01

Discusses several points made by Keegan in an article of the same title which appeared in "Distance Education" in March 1980 and also classifies the different types of distance education and their respective philosophies and teaching requirements. (EAO)

Modeling abundance using hierarchical distance sampling

USGS Publications Warehouse

Royle, Andy; Kery, Marc

2016-01-01

In this chapter, we provide an introduction to classical distance sampling ideas for point and line transect data, and for continuous and binned distance data. We introduce the conditional and the full likelihood, and we discuss Bayesian analysis of these models in BUGS using the idea of data augmentation, which we discussed in Chapter 7. We then extend the basic ideas to the problem of hierarchical distance sampling (HDS), where we have multiple point or transect sample units in space (or possibly in time). The benefit of HDS in practice is that it allows us to directly model spatial variation in population size among these sample units. This is a preeminent concern of most field studies that use distance sampling methods, but it is not a problem that has received much attention in the literature. We show how to analyze HDS models in both the unmarked package and in the BUGS language for point and line transects, and for continuous and binned distance data. We provide a case study of HDS applied to a survey of the island scrub-jay on Santa Cruz Island, California.

Long Distance Caregiving

MedlinePlus

... Navigation Bar Home Current Issue Past Issues Feature: Senior Living Long Distance Caregiving Past Issues / Summer 2009 ... when a crisis occurs. Get a directory of senior resources and services from the local library or ...

Isolation-by-distance in landscapes: considerations for landscape genetics

PubMed Central

van Strien, M J; Holderegger, R; Van Heck, H J

2015-01-01

In landscape genetics, isolation-by-distance (IBD) is regarded as a baseline pattern that is obtained without additional effects of landscape elements on gene flow. However, the configuration of suitable habitat patches determines deme topology, which in turn should affect rates of gene flow. IBD patterns can be characterized either by monotonically increasing pairwise genetic differentiation (for example, FST) with increasing interdeme geographic distance (case-I pattern) or by monotonically increasing pairwise genetic differentiation up to a certain geographical distance beyond which no correlation is detectable anymore (case-IV pattern). We investigated if landscape configuration influenced the rate at which a case-IV pattern changed to a case-I pattern. We also determined at what interdeme distance the highest correlation was measured between genetic differentiation and geographic distance and whether this distance corresponded to the maximum migration distance. We set up a population genetic simulation study and assessed the development of IBD patterns for several habitat configurations and maximum migration distances. We show that the rate and likelihood of the transition of case-IV to case-I FST–distance relationships was strongly influenced by habitat configuration and maximum migration distance. We also found that the maximum correlation between genetic differentiation and geographic distance was not related to the maximum migration distance and was measured across all deme pairs in a case-I pattern and, for a case-IV pattern, at the distance where the FST–distance curve flattens out. We argue that in landscape genetics, separate analyses should be performed to either assess IBD or the landscape effects on gene flow. PMID:25052412

Absolute Distance Measurement with the MSTAR Sensor

NASA Technical Reports Server (NTRS)

Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

2003-01-01

The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

Distance Education Research Priorities for Australia: A Study of the Opinions of Distance Educators and Practitioners.

ERIC Educational Resources Information Center

Jegede, Olugbemiro J.

A group of 56 randomly selected members of the International Council for Distance Education who were based in Australia were surveyed regarding their opinions on distance education research priorities for Australia. A five-page questionnaire was used to gather biographical details about respondents and opinions regarding available level of…

14 CFR 25.113 - Takeoff distance and takeoff run.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Takeoff distance and takeoff run. 25.113... and takeoff run. (a) Takeoff distance on a dry runway is the greater of— (1) The horizontal distance... include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a...

14 CFR 25.113 - Takeoff distance and takeoff run.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff distance and takeoff run. 25.113... and takeoff run. (a) Takeoff distance on a dry runway is the greater of— (1) The horizontal distance... include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a...

Stereoscopic perception of real depths at large distances.

PubMed

Palmisano, Stephen; Gillam, Barbara; Govan, Donovan G; Allison, Robert S; Harris, Julie M

2010-06-01

There has been no direct examination of stereoscopic depth perception at very large observation distances and depths. We measured perceptions of depth magnitude at distances where it is frequently reported without evidence that stereopsis is non-functional. We adapted methods pioneered at distances up to 9 m by R. S. Allison, B. J. Gillam, and E. Vecellio (2009) for use in a 381-m-long railway tunnel. Pairs of Light Emitting Diode (LED) targets were presented either in complete darkness or with the environment lit as far as the nearest LED (the observation distance). We found that binocular, but not monocular, estimates of the depth between pairs of LEDs increased with their physical depths up to the maximum depth separation tested (248 m). Binocular estimates of depth were much larger with a lit foreground than in darkness and increased as the observation distance increased from 20 to 40 m, indicating that binocular disparity can be scaled for much larger distances than previously realized. Since these observation distances were well beyond the range of vertical disparity and oculomotor cues, this scaling must rely on perspective cues. We also ran control experiments at smaller distances, which showed that estimates of depth and distance correlate poorly and that our metric estimation method gives similar results to a comparison method under the same conditions.

Who Am I as a Distance Tutor? An Investigation of Distance Tutors' Professional Identity in China

ERIC Educational Resources Information Center

Xiao, Junhong

2016-01-01

Much research has been conducted in the area of teacher professional identity in the past decades. Nonetheless, very little attention has been paid to the professional identity of tutors in distance education. Using interviews, this study set out to investigate distance tutors' claimed and assigned professional identities, their actual, ought and…

47 CFR 1.958 - Distance computation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Distance computation. 1.958 Section 1.958 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Wireless Radio Services Applications and Proceedings Application Requirements and Procedures § 1.958 Distance computation. The method...

47 CFR 1.958 - Distance computation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Distance computation. 1.958 Section 1.958 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Wireless Radio Services Applications and Proceedings Application Requirements and Procedures § 1.958 Distance computation. The method...

Manifold Learning by Preserving Distance Orders.

PubMed

Ataer-Cansizoglu, Esra; Akcakaya, Murat; Orhan, Umut; Erdogmus, Deniz

2014-03-01

Nonlinear dimensionality reduction is essential for the analysis and the interpretation of high dimensional data sets. In this manuscript, we propose a distance order preserving manifold learning algorithm that extends the basic mean-squared error cost function used mainly in multidimensional scaling (MDS)-based methods. We develop a constrained optimization problem by assuming explicit constraints on the order of distances in the low-dimensional space. In this optimization problem, as a generalization of MDS, instead of forcing a linear relationship between the distances in the high-dimensional original and low-dimensional projection space, we learn a non-decreasing relation approximated by radial basis functions. We compare the proposed method with existing manifold learning algorithms using synthetic datasets based on the commonly used residual variance and proposed percentage of violated distance orders metrics. We also perform experiments on a retinal image dataset used in Retinopathy of Prematurity (ROP) diagnosis.

Automobile Stopping Distances.

ERIC Educational Resources Information Center

Logue, L. J.

1979-01-01

Discusses the effect of vehicle mass on stopping distances. Analyzes an example of a sample vehicle and tire, and calculates the braking acceleration showing the effect of different factors on the stopping performance of the tires. (GA)

Audiences and Providers of Distance Education

ERIC Educational Resources Information Center

Nazarinia Roy, R. Roudi; Schumm, Walter R.

2011-01-01

As noted by Moore (2007, xxiii), the fifth section of the second edition of the "Handbook of Distance Education" focused on "some of the main consumers and suppliers of distance education programs," including elementary and secondary education, community colleges, universities, the corporate sector, continuing professional…

Optimum viewing distance for target acquisition

NASA Astrophysics Data System (ADS)

Holst, Gerald C.

2015-05-01

Human visual system (HVS) "resolution" (a.k.a. visual acuity) varies with illumination level, target characteristics, and target contrast. For signage, computer displays, cell phones, and TVs a viewing distance and display size are selected. Then the number of display pixels is chosen such that each pixel subtends 1 min-1. Resolution of low contrast targets is quite different. It is best described by Barten's contrast sensitivity function. Target acquisition models predict maximum range when the display pixel subtends 3.3 min-1. The optimum viewing distance is nearly independent of magnification. Noise increases the optimum viewing distance.

Graph edit distance from spectral seriation.

PubMed

Robles-Kelly, Antonio; Hancock, Edwin R

2005-03-01

This paper is concerned with computing graph edit distance. One of the criticisms that can be leveled at existing methods for computing graph edit distance is that they lack some of the formality and rigor of the computation of string edit distance. Hence, our aim is to convert graphs to string sequences so that string matching techniques can be used. To do this, we use a graph spectral seriation method to convert the adjacency matrix into a string or sequence order. We show how the serial ordering can be established using the leading eigenvector of the graph adjacency matrix. We pose the problem of graph-matching as a maximum a posteriori probability (MAP) alignment of the seriation sequences for pairs of graphs. This treatment leads to an expression in which the edit cost is the negative logarithm of the a posteriori sequence alignment probability. We compute the edit distance by finding the sequence of string edit operations which minimizes the cost of the path traversing the edit lattice. The edit costs are determined by the components of the leading eigenvectors of the adjacency matrix and by the edge densities of the graphs being matched. We demonstrate the utility of the edit distance on a number of graph clustering problems.

Modeling abundance effects in distance sampling

USGS Publications Warehouse

Royle, J. Andrew; Dawson, D.K.; Bates, S.

2004-01-01

Distance-sampling methods are commonly used in studies of animal populations to estimate population density. A common objective of such studies is to evaluate the relationship between abundance or density and covariates that describe animal habitat or other environmental influences. However, little attention has been focused on methods of modeling abundance covariate effects in conventional distance-sampling models. In this paper we propose a distance-sampling model that accommodates covariate effects on abundance. The model is based on specification of the distance-sampling likelihood at the level of the sample unit in terms of local abundance (for each sampling unit). This model is augmented with a Poisson regression model for local abundance that is parameterized in terms of available covariates. Maximum-likelihood estimation of detection and density parameters is based on the integrated likelihood, wherein local abundance is removed from the likelihood by integration. We provide an example using avian point-transect data of Ovenbirds (Seiurus aurocapillus) collected using a distance-sampling protocol and two measures of habitat structure (understory cover and basal area of overstory trees). The model yields a sensible description (positive effect of understory cover, negative effect on basal area) of the relationship between habitat and Ovenbird density that can be used to evaluate the effects of habitat management on Ovenbird populations.

Can you go the distance? Attending the virtual classroom.

PubMed

Bigony, Lorraine

2010-01-01

Distance learning via the World Wide Web offers convenience and flexibility. Online education connects nurses geographically in a manner that the traditional face-to-face learning environment lacks. Delivered in both a synchronous (real time interaction) or asynchronous (delayed interaction) format, distance programs continue to provide nurses with choice, especially in the pursuit of advanced degrees. This article explores the pros and cons of distance education, in addition to the most popular platform used in distance learning today, the Blackboard Academic Suite. Characteristics of the potential enrollee to ensure a successful distance education experience are also discussed. Distance nursing programs are here to stay. Although rigorous, the ease of accessibility makes distance learning a viable alternative for busy nurses.

Preferred viewing distance of liquid crystal high-definition television.

PubMed

Lee, Der-Song

2012-01-01

This study explored the effect of TV size, illumination, and viewing angle on preferred viewing distance in high-definition liquid crystal display televisions (HDTV). Results showed that the mean preferred viewing distance was 2856 mm. TV size and illumination significantly affected preferred viewing distance. The larger the screen size, the greater the preferred viewing distance, at around 3-4 times the width of the screen (W). The greater the illumination, the greater the preferred viewing distance. Viewing angle also correlated significantly with preferred viewing distance. The more deflected from direct frontal view, the shorter the preferred viewing distance seemed to be. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Improving Distance Courses: Understanding Teacher Trainees and Their Learning Styles for the Design of Teacher Training Courses and Materials at a Distance

ERIC Educational Resources Information Center

Dzakiria, Hisham; Razak, Asmahan Abdul; Mohamed, Abdul Halim

2004-01-01

Literature on distance education and teacher education seems to show that what we do not know about Distance Teacher Trainees (DTT) and their learning process involved exceeds what we know about it. As more DTT enroll in distance education programmes globally, distance education providers and institutions will witness trainees coming with…

[Osteoarthritis from long-distance running?].

PubMed

Hohmann, E; Wörtler, K; Imhoff, A

2005-06-01

Long distance running has become a fashionable recreational activity. This study investigated the effects of external impact loading on bone and cartilage introduced by performing a marathon race. Seven beginners were compared to six experienced recreational long distance runners and two professional athletes. All participants underwent magnetic resonance imaging of the hip and knee before and after a marathon run. Coronal T1 weighted and STIR sequences were used. The pre MRI served as a baseline investigation and monitored the training effect. All athletes demonstrated normal findings in the pre run scan. All but one athlete in the beginner group demonstrated joint effusions after the race. The experienced and professional runners failed to demonstrate pathology in the post run scans. Recreational and professional long distance runners tolerate high impact forces well. Beginners demonstrate significant changes on the post run scans. Whether those findings are a result of inadequate training (miles and duration) warrant further studies. We conclude that adequate endurance training results in adaptation mechanisms that allow the athlete to compensate for the stresses introduced by long distance running and do not predispose to the onset of osteoarthritis. Significant malalignment of the lower extremity may cause increased focal loading of joint and cartilage.

Measuring short distance dispersal of Alliaria petiolata and determining potential long distance dispersal mechanisms

PubMed Central

Anderson, Roger C.

2018-01-01

Introduction Alliaria petiolata, an herbaceous plant, has invaded woodlands in North America. Its ecology has been thoroughly studied, but an overlooked aspect of its biology is seed dispersal distances and mechanisms. We measured seed dispersal distances in the field and tested if epizoochory is a potential mechanism for long-distance seed dispersal. Methods Dispersal distances were measured by placing seed traps in a sector design around three seed point sources, which consisted of 15 second-year plants transplanted within a 0.25 m radius circle. Traps were placed at intervals ranging from 0.25–3.25 m from the point source. Traps remained in the field until a majority of seeds were dispersed. Eight probability density functions were fitted to seed trap counts via maximum likelihood. Epizoochory was tested as a potential seed dispersal mechanism for A. petiolata through a combination of field and laboratory experiments. To test if small mammals transport A. petiolata seeds in their fur, experimental blocks were placed around dense A. petiolata patches. Each block contained a mammal inclusion treatment (MIT) and control. The MIT consisted of a wood-frame (31 × 61× 31 cm) covered in wire mesh, except for the two 31 × 31 cm ends, placed over a germination tray filled with potting soil. A pan filled with bait was placed in the center of the tray. The control frame (11 × 31 × 61 cm) was placed over a germination tray and completely covered in wire mesh to exclude animal activity. Treatments were in the field for peak seed dispersal. In March, trays were moved to a greenhouse and A. petiolata seedlings were counted and then compared between treatments. To determine if A. petiolata seeds attach to raccoon (Procyon lotor) and white-tailed deer (Odocoileus virginianus) fur, wet and dry seeds were dropped onto wet and dry fur. Furs were rotated 180 degrees and the seeds that remained attached were counted. To measure seed retention, seeds were dropped on

Three Generations of Distance Education Pedagogy

ERIC Educational Resources Information Center

Anderson, Terry; Dron, Jon

2011-01-01

This paper defines and examines three generations of distance education pedagogy. Unlike earlier classifications of distance education based on the technology used, this analysis focuses on the pedagogy that defines the learning experiences encapsulated in the learning design. The three generations of cognitive-behaviourist, social constructivist,…

New Strategy of the Distance Education

ERIC Educational Resources Information Center

Bunyatova, Fatma Khanim; Salamov, Gulbala

2014-01-01

This article is dedicated to new strategy of distance education. The article deals with the possibilities of ICT (Information and Communication Technologies) in teaching specially distance education. In the article, ICT technological tools and their methods of application in educational process are looked over; discrepancy of intellectual…

49 CFR 176.708 - Segregation distances.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation distances. 176.708 Section 176.708... Requirements for Radioactive Materials § 176.708 Segregation distances. (a) Table IV lists minimum separation... into account any relocation of cargo during the voyage. (e) Any departure from the segregation...

Theme: Agricultural Education and Distance Education.

ERIC Educational Resources Information Center

Murphy, Tim H.; And Others

1996-01-01

Includes "The Time Is Now" (Murphy); "Technological Solution in Search of an Instructional Problem" (Willis, Touchstone); "'Principles' of Distance Education" (Peasley); "A Star Is Born!" (Swan); "Enrichment in the Classroom" (Blume, Talbert); "Practical Applications for Distance Education Technologies in Remote and Rural Areas" (Davis, Frick);…

Handwriting individualization using distance and rarity

NASA Astrophysics Data System (ADS)

Tang, Yi; Srihari, Sargur; Srinivasan, Harish

2012-01-01

Forensic individualization is the task of associating observed evidence with a specific source. The likelihood ratio (LR) is a quantitative measure that expresses the degree of uncertainty in individualization, where the numerator represents the likelihood that the evidence corresponds to the known and the denominator the likelihood that it does not correspond to the known. Since the number of parameters needed to compute the LR is exponential with the number of feature measurements, a commonly used simplification is the use of likelihoods based on distance (or similarity) given the two alternative hypotheses. This paper proposes an intermediate method which decomposes the LR as the product of two factors, one based on distance and the other on rarity. It was evaluated using a data set of handwriting samples, by determining whether two writing samples were written by the same/different writer(s). The accuracy of the distance and rarity method, as measured by error rates, is significantly better than the distance method.

Reliability of reference distances used in photogrammetry.

PubMed

Aksu, Muge; Kaya, Demet; Kocadereli, Ilken

2010-07-01

To determine the reliability of the reference distances used for photogrammetric assessment. The sample consisted of 100 subjects with mean ages of 22.97 +/- 2.98 years. Five lateral and four frontal parameters were measured directly on the subjects' faces. For photogrammetric assessment, two reference distances for the profile view and three reference distances for the frontal view were established. Standardized photographs were taken and all the parameters that had been measured directly on the face were measured on the photographs. The reliability of the reference distances was checked by comparing direct and indirect values of the parameters obtained from the subjects' faces and photographs. Repeated measure analysis of variance (ANOVA) and Bland-Altman analyses were used for statistical assessment. For profile measurements, the indirect values measured were statistically different from the direct values except for Sn-Sto in male subjects and Prn-Sn and Sn-Sto in female subjects. The indirect values of Prn-Sn and Sn-Sto were reliable in both sexes. The poorest results were obtained in the indirect values of the N-Sn parameter for female subjects and the Sn-Me parameter for male subjects according to the Sa-Sba reference distance. For frontal measurements, the indirect values were statistically different from the direct values in both sexes except for one in male subjects. The indirect values measured were not statistically different from the direct values for Go-Go. The indirect values of Ch-Ch were reliable in male subjects. The poorest results were obtained according to the P-P reference distance. For profile assessment, the T-Ex reference distance was reliable for Prn-Sn and Sn-Sto in both sexes. For frontal assessment, Ex-Ex and En-En reference distances were reliable for Ch-Ch in male subjects.

Finding Distances to Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-03-01

Type Ia supernovae are known as standard candles due to their consistency, allowing us to measure distances based on their brightness. But what if these explosions arent quite as consistent as we thought? Due scientific diligence requires careful checks, so a recent study investigates whether the metallicity of a supernovas environment affects the peak luminosity of the explosion.Metallicity Dependence?Type Ia supernovae are incredibly powerful tools for determining distances in our universe. Because these supernovae are formed by white dwarfs that explode when they reach a uniform accreted mass, the supernova peak luminosity is thought to be very consistent. This consistency allows these supernovae to be used as standard candles to measure distances to their host galaxies.But what if that peak luminosity is affected by a factor that we havent taken into account? Theorists have proposed that the luminosities of Type Ia supernovae might depend on the metallicity of their environments with high-metallicity environments suppressing supernova luminosities. If this is true, then we could be systematically mis-measuring cosmological distances using these supernovae.Testing AbundancesSupernova brightnesses vs. the metallicity of their environments. Low-metallicity supernovae (blue shading) and high-metallicity supernovae (red shading) have an average magnitude difference of ~0.14. [Adapted from Moreno-Raya et al. 2016]A team led by Manuel Moreno-Raya, of the Center for Energy, Environment and Technology (CIEMAT) in Spain, has observed 28 Type Ia supernovae in an effort to test for such a metallicity dependence. These supernovae each have independent distance measurements (e.g., from Cepheids or the Tully-Fisher relation).Moreno-Raya and collaborators used spectra from the 4.2-m William Herschel Telescope to estimate oxygen abundances in the region where each of these supernovae exploded. They then used these measurements to determine if metallicity of the local region

Designing Instruction for the Distance Learner

ERIC Educational Resources Information Center

Asunda, Paul A.

2010-01-01

A changing education landscape, diverse learner needs and technological advancements make this the perfect time for online and distance learning. Distance learning is increasingly becoming a preferred means for individuals to gain access to education and job preparation opportunities; this meets the public's learning needs "and" that of an…

Distance caregiving a family member with cancer: A review of the literature on distance caregiving and recommendations for future research

PubMed Central

Douglas, Sara L; Mazanec, Polly; Lipson, Amy; Leuchtag, Mary

2016-01-01

Distance caregivers (DCGs) are a growing phenomenon in the United States Family members are struggling to provide care to loved ones with chronic illnesses such as cancer, from a distance. Unlike local caregiving research, distance caregiving research is limited and inconsistent definitions of distance make it difficult to compare studies. To date, DCGs have not been afforded the opportunities for educational and emotional support that local caregivers have received from the health care teams. Because they are not usually present at medical appointments, DCGs do not receive first-hand information from the health care team about the patient’s condition, disease progression, and/or treatment options. These caregivers report feeling left out of important family discussions. They experience anxiety related to the uncertainty of the family members’ well-being and guilt related to not being available to help local caregivers more. The challenges of distance caregiving are especially evident when the distance caregiver has a parent with advanced cancer. Family-centered care, attending to the needs of the whole family regardless of their geographic location is critical for quality cancer care. In this manuscript, the sparse literature on distance caregiving is reviewed. Recommendations for future research and for the development of creative technologically advanced interventions for this underserved caregiving population are suggested. PMID:27081643

Distance caregiving a family member with cancer: A review of the literature on distance caregiving and recommendations for future research.

PubMed

Douglas, Sara L; Mazanec, Polly; Lipson, Amy; Leuchtag, Mary

2016-04-10

Distance caregivers (DCGs) are a growing phenomenon in the United States Family members are struggling to provide care to loved ones with chronic illnesses such as cancer, from a distance. Unlike local caregiving research, distance caregiving research is limited and inconsistent definitions of distance make it difficult to compare studies. To date, DCGs have not been afforded the opportunities for educational and emotional support that local caregivers have received from the health care teams. Because they are not usually present at medical appointments, DCGs do not receive first-hand information from the health care team about the patient's condition, disease progression, and/or treatment options. These caregivers report feeling left out of important family discussions. They experience anxiety related to the uncertainty of the family members' well-being and guilt related to not being available to help local caregivers more. The challenges of distance caregiving are especially evident when the distance caregiver has a parent with advanced cancer. Family-centered care, attending to the needs of the whole family regardless of their geographic location is critical for quality cancer care. In this manuscript, the sparse literature on distance caregiving is reviewed. Recommendations for future research and for the development of creative technologically advanced interventions for this underserved caregiving population are suggested.

A VLBI resolution of the Pleiades distance controversy.

PubMed

Melis, Carl; Reid, Mark J; Mioduszewski, Amy J; Stauffer, John R; Bower, Geoffrey C

2014-08-29

Because of its proximity and its youth, the Pleiades open cluster of stars has been extensively studied and serves as a cornerstone for our understanding of the physical properties of young stars. This role is called into question by the "Pleiades distance controversy," wherein the cluster distance of 120.2 ± 1.5 parsecs (pc) as measured by the optical space astrometry mission Hipparcos is significantly different from the distance of 133.5 ± 1.2 pc derived with other techniques. We present an absolute trigonometric parallax distance measurement to the Pleiades cluster that uses very long baseline radio interferometry (VLBI). This distance of 136.2 ± 1.2 pc is the most accurate and precise yet presented for the cluster and is incompatible with the Hipparcos distance determination. Our results cement existing astrophysical models for Pleiades-age stars. Copyright © 2014, American Association for the Advancement of Science.

A Short-Range Distance Sensor with Exceptional Linearity

NASA Technical Reports Server (NTRS)

Simmons, Steven; Youngquist, Robert

2013-01-01

A sensor has been demonstrated that can measure distance over a total range of about 300 microns to an accuracy of about 0.1 nm (resolution of about 0.01 nm). This represents an exceptionally large dynamic range of operation - over 1,000,000. The sensor is optical in nature, and requires the attachment of a mirror to the object whose distance is being measured. This work resulted from actively developing a white light interferometric system to be used to measure the depths of defects in the Space Shuttle Orbiter windows. The concept was then applied to measuring distance. The concept later expanded to include spectrometer calibration. In summary, broadband (i.e., white) light is launched into a Michelson interferometer, one mirror of which is fixed and one of which is attached to the object whose distance is to be measured. The light emerging from the interferometer has traveled one of two distances: either the distance to the fixed mirror and back, or the distance to the moving mirror and back. These two light beams mix and produce an interference pattern where some wavelengths interfere constructively and some destructively. Sending this light into a spectrometer allows this interference pattern to be analyzed, yielding the net distance difference between the two paths. The unique feature of this distance sensor is its ability to measure accurately distance over a dynamic range of more than one million, the ratio of its range (about 300 microns) to its accuracy (about 0.1 nanometer). Such a large linear operating range is rare and arises here because both amplitude and phase-matching algorithms contribute to the performance. The sensor is limited by the need to attach a mirror of some kind to the object being tracked, and by the fairly small total range, but the exceptional dynamic range should make it of interest.

Prediction of distance in hammer throwing.

PubMed

Dapena, Jesús; Gutiérrez-Dávila, Marcos; Soto, Víctor M; Rojas, Francisco J

2003-01-01

The aim of this study was to determine how much the predicted distance of a hammer throw is affected by (1) ignoring air resistance and (2) assuming that the centre of mass of the hammer coincides with the centre of the ball. Three-dimensional data from actual throws (men: 72.82 +/- 7.43 m; women: 67.78 +/- 4.02 m) were used to calculate the kinematic conditions of the hammer at release. A mathematical model of the hammer was then used to simulate the three-dimensional airborne motion of the hammer and to predict the distance of the throw. The distance predicted for vacuum conditions and using the ball centre to represent the hammer centre of mass was 4.30 +/- 2.64 m longer than the official distance of the throw for the men and 8.82 +/- 3.20 m longer for the women. Predictions using the true centre of mass of the hammer reduced the discrepancy to 2.39 +/- 2.58 m for the men and 5.28 +/- 2.88 m for the women. Predictions using air resistance and the true centre of mass of the hammer further reduced the discrepancy to -0.46 +/- 2.63 m for the men and 1.16 +/- 2.31 m for the women. Approximately half the loss of distance produced by air resistance was due to forces made on the ball and the remainder to forces made on the cable and handle. Equations were derived for calculation of the effects of air resistance and of the assumption that the centre of mass of the hammer coincides with the centre of the ball, on the distance of the throw.

Mobile Distance Learning with PDAs: Development and Testing of Pedagogical and System Solutions Supporting Mobile Distance Learners

ERIC Educational Resources Information Center

Rekkedal, Torstein; Dye, Aleksander

2007-01-01

The article discusses basic teaching-learning philosophies and experiences from the development and testing of mobile learning integrated with the online distance education system at NKI (Norwegian Knowledge Institute) Distance Education. The article builds on experiences from three European Union (EU) supported "Leonardo da Vinci"…

Distance Education at Arm's Length: Outsourcing of Distance Education Marking.

ERIC Educational Resources Information Center

Smith, Erica; Coombe, Kennece

Two research projects focused on use of casual markers (graders) for correcting and grading distance education (DE) students' work. A Charles Sturt University project convened focus groups of DE students, casual DE markers, and lecturers who "managed" markers to uncover concerns. University of South Australia research focused on pedagogical issues…

Distance Learning Programming.

ERIC Educational Resources Information Center

Lucero, Jesus Ricardo; And Others

This resource guide for distance learning information, courses, and programming covers: (1) audiographics programming by the Pennsylvania Teleteaching Project; (2) cable programming, including the Cable Alliance for Education's Cable in the Classroom projects, Consumer News and Business Channel, Nostalgia Television, PENNARAMA Channel, Silent…

International Distance Education.

ERIC Educational Resources Information Center

Perrin, Don; Perrin, Elizabeth

1995-01-01

Reports on the Commonwealth of Learning (COL) and its role in furthering the use of distance learning technology. Highlights include activities; telecommunications; educational media; training; planning and advice; strategic alliances and outlooks; public administration; student record/management system; institutional and material development; a…

Scalable parallel distance field construction for large-scale applications

DOE PAGES

Yu, Hongfeng; Xie, Jinrong; Ma, Kwan -Liu; ...

2015-10-01

Computing distance fields is fundamental to many scientific and engineering applications. Distance fields can be used to direct analysis and reduce data. In this paper, we present a highly scalable method for computing 3D distance fields on massively parallel distributed-memory machines. Anew distributed spatial data structure, named parallel distance tree, is introduced to manage the level sets of data and facilitate surface tracking overtime, resulting in significantly reduced computation and communication costs for calculating the distance to the surface of interest from any spatial locations. Our method supports several data types and distance metrics from real-world applications. We demonstrate itsmore » efficiency and scalability on state-of-the-art supercomputers using both large-scale volume datasets and surface models. We also demonstrate in-situ distance field computation on dynamic turbulent flame surfaces for a petascale combustion simulation. In conclusion, our work greatly extends the usability of distance fields for demanding applications.« less

Scalable Parallel Distance Field Construction for Large-Scale Applications.

PubMed

Yu, Hongfeng; Xie, Jinrong; Ma, Kwan-Liu; Kolla, Hemanth; Chen, Jacqueline H

2015-10-01

Computing distance fields is fundamental to many scientific and engineering applications. Distance fields can be used to direct analysis and reduce data. In this paper, we present a highly scalable method for computing 3D distance fields on massively parallel distributed-memory machines. A new distributed spatial data structure, named parallel distance tree, is introduced to manage the level sets of data and facilitate surface tracking over time, resulting in significantly reduced computation and communication costs for calculating the distance to the surface of interest from any spatial locations. Our method supports several data types and distance metrics from real-world applications. We demonstrate its efficiency and scalability on state-of-the-art supercomputers using both large-scale volume datasets and surface models. We also demonstrate in-situ distance field computation on dynamic turbulent flame surfaces for a petascale combustion simulation. Our work greatly extends the usability of distance fields for demanding applications.

Do Pre-school Distance Educators Require Specialist Training?

ERIC Educational Resources Information Center

Kirk, David

1994-01-01

Recommends implementing specialized preparation for rural preschool teachers to function effectively as distance educators. Addresses differences between urban and rural environments affecting education; the important role of parents as educators in distance education; and the need for distance education preschool teachers to reconceptualize their…

Optical distance measurement device and method thereof

DOEpatents

Bowers, Mark W.

2003-05-27

A system and method of efficiently obtaining distance measurements of a target. A modulated optical beam may be used to determine the distance to the target. A first beam splitter may be used to split the optical beam and a second beam splitter may be used to recombine a reference beam with a return ranging beam. An optical mixing detector may be used in a receiver to efficiently detect distance measurement information.

Asymmetric distances for binary embeddings.

PubMed

Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

2014-01-01

In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

Distance to Dark Bodies

NASA Technical Reports Server (NTRS)

2007-01-01

Using the unique orbit of NASA's Spitzer Space Telescope and a depth-perceiving trick called parallax, astronomers have determined the distance to an invisible Milky Way object called OGLE-2005-SMC-001. This artist's concept illustrates how this trick works: different views from both Spitzer and telescopes on Earth are combined to give depth perception.

Our Milky Way galaxy is heavier than it looks, and scientists use the term 'dark matter' to describe all the 'heavy stuff' in the universe that seems to be present but invisible to our telescopes. While much of this dark matter is likely made up of exotic materials, different from the ordinary particles that make up the world around us, some may consist of dark celestial bodies -- like planets, black holes, or failed stars -- that do not produce light or are too faint to detect from Earth. OGLE-2005-SMC-001 is one of these dark celestial bodies.

Although astronomers cannot see a dark body, they can sense its presence from the way light acts around it. When a dark body like OGLE-2005-SMC-001 passes in front of a bright star, its gravity causes the background starlight to bend and brighten, a process called gravitational microlensing. When the observing telescope, dark body, and star system are closely aligned, the microlensing event reaches maximum, or peak, brightness.

A team of astronomers first sensed OGLE-2005-SMC-001's presence when it passed in front of a star in a neighboring satellite galaxy called the Small Magellanic Cloud. In this artist's rendering, the satellite galaxy is depicted as the fuzzy structure sitting to the left of Earth. Once they detected this microlensing event, the scientists used Spitzer and the principle of parallax to figure out its distance. Humans naturally use parallax to determine distance. Each eye sees the distance of an object differently. The brain takes each eye's perspective and instantaneously calculates how far away the object is.

To determine OGLE

International Perspectives of Distance Learning in Higher Education

ERIC Educational Resources Information Center

Moore, Joi L., Ed.; Benson, Angela D., Ed.

2012-01-01

This book, written by authors representing 12 countries and five continents, is a collection of international perspectives on distance learning and distance learning implementations in higher education. The perspectives are presented in the form of practical case studies of distance learning implementations, research studies on teaching and…

Challenges in Delivering Library Services for Distance Learning.

ERIC Educational Resources Information Center

Swaine, Cynthia Wright

The first section of this paper on library services for distance education discusses the status of distance learning in higher education. What distance learning means for libraries is addressed in the second section, including considerations related to diverse locations, agreements with participating institutions, delivery limitations, librarian…

Probability Distributions of Minkowski Distances between Discrete Random Variables.

ERIC Educational Resources Information Center

Schroger, Erich; And Others

1993-01-01

Minkowski distances are used to indicate similarity of two vectors in an N-dimensional space. How to compute the probability function, the expectation, and the variance for Minkowski distances and the special cases City-block distance and Euclidean distance. Critical values for tests of significance are presented in tables. (SLD)

Positioning for Effectiveness: Applying Marketing Concepts to Distance Education.

ERIC Educational Resources Information Center

Levenburg, Nancy

1997-01-01

Demonstrates how colleges can use distance education to attract and retain a "critical mass" of learners for distance programs. Explores alternative ways to view distance education market opportunities and determine which avenues to pursue. Suggests how to be more effective in all aspects of distance education programs. (13 citations) (YKH)

Site-to-Source Finite Fault Distance Probability Distribution in Probabilistic Seismic Hazard and the Relationship Between Minimum Distances

NASA Astrophysics Data System (ADS)

Ortega, R.; Gutierrez, E.; Carciumaru, D. D.; Huesca-Perez, E.

2017-12-01

We present a method to compute the conditional and no-conditional probability density function (PDF) of the finite fault distance distribution (FFDD). Two cases are described: lines and areas. The case of lines has a simple analytical solution while, in the case of areas, the geometrical probability of a fault based on the strike, dip, and fault segment vertices is obtained using the projection of spheres in a piecewise rectangular surface. The cumulative distribution is computed by measuring the projection of a sphere of radius r in an effective area using an algorithm that estimates the area of a circle within a rectangle. In addition, we introduce the finite fault distance metrics. This distance is the distance where the maximum stress release occurs within the fault plane and generates a peak ground motion. Later, we can apply the appropriate ground motion prediction equations (GMPE) for PSHA. The conditional probability of distance given magnitude is also presented using different scaling laws. A simple model of constant distribution of the centroid at the geometrical mean is discussed, in this model hazard is reduced at the edges because the effective size is reduced. Nowadays there is a trend of using extended source distances in PSHA, however it is not possible to separate the fault geometry from the GMPE. With this new approach, it is possible to add fault rupture models separating geometrical and propagation effects.

Exploring Cloud Computing for Distance Learning

ERIC Educational Resources Information Center

He, Wu; Cernusca, Dan; Abdous, M'hammed

2011-01-01

The use of distance courses in learning is growing exponentially. To better support faculty and students for teaching and learning, distance learning programs need to constantly innovate and optimize their IT infrastructures. The new IT paradigm called "cloud computing" has the potential to transform the way that IT resources are utilized and…

Writing for Distance Education. Samples Booklet.

ERIC Educational Resources Information Center

International Extension Coll., Cambridge (England).

Approaches to the format, design, and layout of printed instructional materials for distance education are illustrated in 36 samples designed to accompany the manual, "Writing for Distance Education." Each sample is presented on a single page with a note pointing out its key features. Features illustrated include use of typescript layout, a comic…

Distance Synchronous Information Systems Course Delivery

ERIC Educational Resources Information Center

Peslak, Alan R.; Lewis, Griffith R.; Aebli, Fred

2014-01-01

Teaching computer information systems via distance education is a challenge for both student and faculty. Much research work has been performed on methods of teaching via distance education. Today we are faced with a variety of options for course delivery. Asynchronous delivery via online or lesson instruction still remains most common. But…

An Active Tutorial on Distance Sampling

ERIC Educational Resources Information Center

Richardson, Alice

2007-01-01

The technique of distance sampling is widely used to monitor biological populations. This paper documents an in-class activity to introduce students to the concepts and the mechanics of distance sampling in a simple situation that is relevant to their own experiences. Preparation details are described. Variations and extensions to the activity are…

Modelling the distance impedance of protest attendance

NASA Astrophysics Data System (ADS)

Traag, V. A.; Quax, R.; Sloot, P. M. A.

2017-02-01

Protesters are usually young, relatively well educated, middle class people that are politically engaged. But where do protesters come from? We here show, based on mobile phone data, that distance is an important impedance to protest attendance. Most protesters come from nearby regions, suggesting distance forms an obstacle to participation. Although this effect can be partly explained by social network effects, which show similar spatial dependencies, an effect of distance remains. This suggests distance still acts as an obstacle to participation, although it may also be that long-range contacts are less effective for recruitment. Face-to-face contacts seem more important in spreading protests through earlier participants, whereas central recruitment works better by telephone. Our results are important for understanding processes of recruitment.

Scaling and Multifractality in Road Accidental Distances

NASA Astrophysics Data System (ADS)

Qiu, Tian; Wan, Chi; Zou, Xiang-Xiang; Wang, Xiao-Fan

Accidental distance dynamics is investigated, based on the road accidental data of the Great Britain. The distance distribution of all the districts as an ensemble presents a power law tail, which is different from that of the individual district. A universal distribution is found for different districts, by rescaling the distribution functions of individual districts, which can be well fitted by the Weibull distribution. The male and female drivers behave similarly in the distance distribution. The multifractal characteristic is further studied for the individual district and all the districts as an ensemble, and different behaviors are also revealed between them. The accidental distances of the individual district show a weak multifractality, whereas of all the districts present a strong multifractality when taking them as an ensemble.

What Research Tells the Coach About Distance Running.

ERIC Educational Resources Information Center

Costill, David L.

This booklet is designed to make available research findins concerning distance running with interpretations, for practical applications, and to point out areas of needed research. Chapter 1, "Describing the Distance Runner," considers the following aspects in relation to the distance runner: a) anatomical characteristics, b) aging, c) strength…

14 CFR 23.59 - Takeoff distance and takeoff run.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Takeoff distance and takeoff run. 23.59... Takeoff distance and takeoff run. For each commuter category airplane, the takeoff distance and, at the option of the applicant, the takeoff run, must be determined. (a) Takeoff distance is the greater of— (1...

14 CFR 23.59 - Takeoff distance and takeoff run.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff distance and takeoff run. 23.59... Takeoff distance and takeoff run. For each commuter category airplane, the takeoff distance and, at the option of the applicant, the takeoff run, must be determined. (a) Takeoff distance is the greater of— (1...

Nearest Neighbor Classification Using a Density Sensitive Distance Measurement

DTIC Science & Technology

2009-09-01

both the proposed density sensitive distance measurement and Euclidean distance are compared on the Wisconsin Diagnostic Breast Cancer dataset and...proposed density sensitive distance measurement and Euclidean distance are compared on the Wisconsin Diagnostic Breast Cancer dataset and the MNIST...35 1. The Wisconsin Diagnostic Breast Cancer (WDBC) Dataset..........35 2. The

Novae as distance indicators

NASA Technical Reports Server (NTRS)

Ford, Holland C.; Ciardullo, Robin

1988-01-01

Nova shells are characteristically prolate with equatorial bands and polar caps. Failure to account for the geometry can lead to large errors in expansion parallaxes for individual novae. When simple prescriptions are used for deriving expansion parallaxes from an ensemble of randomly oriented prolate spheroids, the average distance will be too small by factors of 10 to 15 percent. The absolute magnitudes of the novae will be underestimated and the resulting distance scale will be too small by the same factors. If observations of partially resolved nova shells select for large inclinations, the systematic error in the resulting distance scale could easily be 20 to 30 percent. Extinction by dust in the bulge of M31 may broaden and shift the intrinsic distribution of maximum nova magnitudes versus decay rates. We investigated this possibility by projecting Arp's and Rosino's novae onto a composite B - 6200A color map of M31's bulge. Thirty two of the 86 novae projected onto a smooth background with no underlying structure due to the presence of a dust cloud along the line of sight. The distribution of maximum magnitudes versus fade rates for these unreddened novae is indistinguishable from the distribution for the entire set of novae. It is concluded that novae suffer very little extinction from the filamentary and patchy distribution of dust seen in the bulge of M31. Time average B and H alpha nova luminosity functions are potentially powerful new ways to use novae as standard candles. Modern CCD observations and the photographic light curves of M31 novae found during the last 60 years were analyzed to show that these functions are power laws. Consequently, unless the eruption times for novae are known, the data cannot be used to obtain distances.

Contemporary Distance Education Leadership: Distance Education Leaders' Perceptions of Leadership Competencies

ERIC Educational Resources Information Center

Tantchou, Pierre Orly M., Jr.

2013-01-01

This phenomenological qualitative study identified the leadership competencies that distance education (DE) leaders regard as essential to the successful administration of DE programs and courses in contemporary education. The following competencies were discussed in the study: flexibility, collaboration, active listening, communication, empathy,…

Distance Learning for Mobile Internet Users

ERIC Educational Resources Information Center

Necat, Beran

2007-01-01

This paper provides an overview on the current state of art in the field of Distance learning for mobile users. It mentions a large range of technologies, services and approaches that may be used to bring distance learning to mobile internet users. These technologies are supposed to considerably increase innovative e-learning solutions for the…

NASA Langley/CNU Distance Learning Programs.

ERIC Educational Resources Information Center

Caton, Randall; Pinelli, Thomas E.

NASA Langley Research Center and Christopher Newport University (CNU) provide, free to the public, distance learning programs that focus on math, science, and/or technology over a spectrum of education levels from K-adult. The effort started in 1997, and currently there are a suite of five distance-learning programs. This paper presents the major…

Investigating Distance Education Students' Study Skills

ERIC Educational Resources Information Center

Poyraz, Cengiz

2013-01-01

Distance education, which is a planned way of teaching in which students and instructors are brought face to face in a classroom environment in several different ways by means of technology, has started to become widespread in many fields today. In distance education, students and instructors reside in different locations. Students can learn at…

How variations in distance affect eyewitness reports and identification accuracy.

PubMed

Lindsay, R C L; Semmler, Carolyn; Weber, Nathan; Brewer, Neil; Lindsay, Marilyn R

2008-12-01

Witnesses observe crimes at various distances and the courts have to interpret their testimony given the likely quality of witnesses' views of events. We examined how accurately witnesses judged the distance between themselves and a target person, and how distance affected description accuracy, choosing behavior, and identification test accuracy. Over 1,300 participants were approached during normal daily activities, and asked to observe a target person at one of a number of possible distances. Under a Perception, Immediate Memory, or Delayed Memory condition, witnesses provided a brief description of the target, estimated the distance to the target, and then examined a 6-person target-present or target-absent lineup to see if they could identify the target. Errors in distance judgments were often substantial. Description accuracy was mediocre and did not vary systematically with distance. Identification choosing rates were not affected by distance, but decision accuracy declined with distance. Contrary to previous research, a 15-m viewing distance was not critical for discriminating accurate from inaccurate decisions.

A Strategic Planning Process Model for Distance Education

ERIC Educational Resources Information Center

Pisel, Kenneth P.

2008-01-01

As more institutions seek to implement or expand distance learning programs, it becomes critical to integrate distance learning programs into broader strategic visions and plans. Using the informed opinion from a panel of peer-nominated experts via iterative Delphi questionnaires, a 10-phased strategic planning process model for distance education…

Importance of Developing Community in Distance Education Courses

ERIC Educational Resources Information Center

Moore, Robert L.

2014-01-01

The separation of student and instructor is the core characteristic of distance education (Simonson et al., 2012, p. 28), contributing to one of the biggest challenges to distance education-attrition (Dueber & Misanchuk, 2001, p. 2). By the very nature of distance education, students are different locations from one another and their…

49 CFR 372.300 - Distances and population data.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 5 2012-10-01 2012-10-01 false Distances and population data. 372.300 Section 372..., COMMERCIAL ZONES, AND TERMINAL AREAS Terminal Areas § 372.300 Distances and population data. In the application of this subpart, distances and population data shall be determined in the same manner as provided...

49 CFR 372.300 - Distances and population data.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Distances and population data. 372.300 Section 372..., COMMERCIAL ZONES, AND TERMINAL AREAS Terminal Areas § 372.300 Distances and population data. In the application of this subpart, distances and population data shall be determined in the same manner as provided...

49 CFR 372.300 - Distances and population data.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Distances and population data. 372.300 Section 372..., COMMERCIAL ZONES, AND TERMINAL AREAS Terminal Areas § 372.300 Distances and population data. In the application of this subpart, distances and population data shall be determined in the same manner as provided...

49 CFR 372.300 - Distances and population data.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Distances and population data. 372.300 Section 372..., COMMERCIAL ZONES, AND TERMINAL AREAS Terminal Areas § 372.300 Distances and population data. In the application of this subpart, distances and population data shall be determined in the same manner as provided...

49 CFR 372.300 - Distances and population data.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Distances and population data. 372.300 Section 372..., COMMERCIAL ZONES, AND TERMINAL AREAS Terminal Areas § 372.300 Distances and population data. In the application of this subpart, distances and population data shall be determined in the same manner as provided...

Digital Learning Compass: Distance Education State Almanac 2017

ERIC Educational Resources Information Center

Seaman, Julia E.; Seaman, Jeff

2017-01-01

The Distance Education State Almanac 2017 reveals very different patterns of distance enrollments among the 50 states. This publication, which includes information for all 50 states, and the accompanying 50 individual state reports, provide the first-ever detailed examination of the state-level differences in distance education. This report uses…

Indo-European languages tree by Levenshtein distance

NASA Astrophysics Data System (ADS)

Serva, M.; Petroni, F.

2008-03-01

The evolution of languages closely resembles the evolution of haploid organisms. This similarity has been recently exploited (Gray R. D. and Atkinson Q. D., Nature, 426 (2003) 435; Gray R. D. and Jordan F. M., Nature, 405 (2000) 1052) to construct language trees. The key point is the definition of a distance among all pairs of languages which is the analogous of a genetic distance. Many methods have been proposed to define these distances; one of these, used by glottochronology, computes the distance from the percentage of shared "cognates". Cognates are words inferred to have a common historical origin, and subjective judgment plays a relevant role in the identification process. Here we push closer the analogy with evolutionary biology and we introduce a genetic distance among language pairs by considering a renormalized Levenshtein distance among words with same meaning and averaging on all words contained in a Swadesh list (Swadesh M., Proc. Am. Philos. Soc., 96 (1952) 452). The subjectivity of process is consistently reduced and the reproducibility is highly facilitated. We test our method against the Indo-European group considering fifty different languages and the two hundred words of the Swadesh list for any of them. We find out a tree which closely resembles the one published in Gray and Atkinson (2003), with some significant differences.

Cosmic equation of state from combined angular diameter distances: Does the tension with luminosity distances exist?

NASA Astrophysics Data System (ADS)

Cao, Shuo; Zhu, Zong-Hong

2014-10-01

Using relatively complete observational data concerning four angular diameter distance (ADD) measurements and combined SN +GRB observations representing current luminosity distance (LD) data, this paper investigates the compatibility of these two cosmological distances considering three classes of dark energy equation of state (EoS) reconstruction. In particular, we use strongly gravitationally lensed systems from various large systematic gravitational lens surveys and galaxy clusters, which yield the Hubble constant independent ratio between two angular diameter distances Dl s/Ds data. Our results demonstrate that, with more general categories of standard ruler data, ADD and LD data are compatible at 1 σ level. Second, we note that consistency between ADD and LD data is maintained irrespective of the EoS parametrizations: there is a good match between the universally explored Chevalier-Polarski-Linder model and other formulations of cosmic equation of state. Especially for the truncated generalized equation of state (GEoS) model with β =-2 , the conclusions obtained with ADD and LD are almost the same. Finally, statistical analysis of generalized dark energy equation of state performed on four classes of ADD data provides stringent constraints on the EoS parameters w0 , wβ, and β , which suggest that dark energy was a subdominant component at early times. Moreover, the GEoS parametrization with β ≃1 seems to be a more favorable two-parameter model to characterize the cosmic equation of state, because the combined angular diameter distance data (SGL +CBF +BAO +WMAP 9 ) provide the best-fit value β =0.75 1-0.480+0.465 .

Teaching and Learning at a Distance: Foundations of Distance Education.

ERIC Educational Resources Information Center

Simonson, Michael; Smaldino, Sharon; Albright, Michael; Zvacek, Susan

This book, which is an introductory-level textbook for preservice or inservice teachers, examines the foundations and practice of distance education (DE) and explains how to determine when DE is appropriate. The following are among the topics discussed in the book's 12 chapters: (1) foundations of DE (DE today and tomorrow, media in education,…

Distance-Based Opportunistic Mobile Data Offloading

PubMed Central

Lu, Xiaofeng; Lio, Pietro; Hui, Pan

2016-01-01

Cellular network data traffic can be offload onto opportunistic networks. This paper proposes a Distance-based Opportunistic Publish/Subscribe (DOPS) content dissemination model, which is composed of three layers: application layer, decision-making layer and network layer. When a user wants new content, he/she subscribes on a subscribing server. Users having the contents decide whether to deliver the contents to the subscriber based on the distance information. If in the meantime a content owner has traveled further in the immediate past time than the distance between the owner and the subscriber, the content owner will send the content to the subscriber through opportunistic routing. Simulations provide an evaluation of the data traffic offloading efficiency of DOPS. PMID:27314361

Distance-Based Opportunistic Mobile Data Offloading.

PubMed

Lu, Xiaofeng; Lio, Pietro; Hui, Pan

2016-06-15

Cellular network data traffic can be offload onto opportunistic networks. This paper proposes a Distance-based Opportunistic Publish/Subscribe (DOPS) content dissemination model, which is composed of three layers: application layer, decision-making layer and network layer. When a user wants new content, he/she subscribes on a subscribing server. Users having the contents decide whether to deliver the contents to the subscriber based on the distance information. If in the meantime a content owner has traveled further in the immediate past time than the distance between the owner and the subscriber, the content owner will send the content to the subscriber through opportunistic routing. Simulations provide an evaluation of the data traffic offloading efficiency of DOPS.

An independent Cepheid distance scale: Current status

NASA Technical Reports Server (NTRS)

Barnes, T. G., III

1980-01-01

An independent distance scale for Cepheid variables is discussed. The apparent magnitude and the visual surface brightness, inferred from an appropriate color index, are used to determine the angular diameter variation of the Cepheid. When combined with the linear displacement curve obtained from the integrated radial velocity curve, the distance and linear radius are determined. The attractiveness of the method is its complete independence of all other stellar distance scales, even though a number of practical difficulties currently exist in implementing the technique.

Blended Learning in Distance Education: Sri Lankan Perspective

ERIC Educational Resources Information Center

Liyanagunawardena, T. R.; Adams, A. A.; Rassool, N.; Williams, S. A.

2014-01-01

The purpose of this paper is to explore the implementation of online learning in distance educational delivery at Yellow Fields University (pseudonymous) in Sri Lanka. The implementation of online distance education at the University included the use of blended learning. The policy initiative to introduce online for distance education in Sri Lanka…

The Landscape of Quality Assurance in Distance Education

ERIC Educational Resources Information Center

Scull, W. Reed; Kendrick, David; Shearer, Rick; Offerman, Dana

2011-01-01

Distance education permeates the field of professional and continuing education to such an extent that quality assurance (QA) is a topic no distance educator or administrator should avoid. Quality assurance is an issue not just for continuing education but also for higher education generally. Given the disruptive impact of distance education and…

Thermodynamics of computation and information distance

NASA Astrophysics Data System (ADS)

Bennett, Charles H.; Gacs, Peter; Li, Ming; Vitanyi, Paul M. R. B.; Zurek, Wojciech H.

1993-06-01

Intuitively, the minimal information distance between x and y is the length of the shortest program for a universal computer to transform x into y and y into x. This measure is shown to be, up to a logarithmic additive term, equal to the maximum of the conditional Kolmogorov complexities E(sub 1)(x,y) = max(K(y/x), K(x/y)). Any reasonable distance to measure similarity of pictures should be an effectively approximable, symmetric, positive function of x and y satisfying a reasonable normalization condition and obeying the triangle inequality. It turns out that E(sub 1) is minimal up to an additive constant among all such distances. Hence it is a universal 'picture distance', which accounts for any effective similarity between pictures. A third information distance, based on the ideal that the aim should be for dissipationless computations, and hence for reversible ones, is given by the length E(sub 2)(x,y) = KR(y/x) = KR(x/y) of the shortest reversible program that transforms x into y and y into x on a universal reversible computer. It is shown that also E(sub 2) = E(sub 1), up to a logarithmic additive term. It is remarkable that three so differently motivated definitions turn out to define one and the same notion. Another information distance, E(sub 3), is obtained by minimizing the total amount of information flowing in and out during a reversible computation in which the program is not retained, in other words the number of extra bits (apart from x) that must be irreversibly supplied at the beginning, plus the number of garbage bits (apart from y) that must be irreversibly erased at the end of the computation to obtain a 'clean' y. This distance is within a logarithmic additive term of the sum of the conditional complexities, E(sub 3)(x, y) = K(y/x) + K(x/y). Using the physical theory of reversible computation, the simple difference K(x) - K(y) is shown to be an appropriate (universal, antisymmetric, and transitive) measure of the amount of thermodynamic work

Subsurface Supergranular Vertical Flows as Measured Using Large Distance Separations in Time-Distance Helioseismology

NASA Technical Reports Server (NTRS)

Duvall, T. L., Jr.; Hanasoge, S. M.

2012-01-01

As large-distance rays (say, 10-24 deg) approach the solar surface approximately vertically, travel times measured from surface pairs for these large separations are mostly sensitive to vertical flows, at least for shallow flows within a few Mm of the solar surface. All previous analyses of supergranulation have used smaller separations and have been hampered by the difficulty of separating the horizontal and vertical flow components. We find that the large separation travel times associated with upergranulation cannot be studied using the standard phase-speed filters of time-distance helioseismology. These filters, whose use is based upon a refractive model of the perturbations,reduce the resultant travel time signal by at least an order of magnitude at some distances. More effective filters are derived. Modeling suggests that the center-annulus travel time difference in the separation range 10-24 deg is insensitive to the horizontally diverging flow from the centers of the supergranules and should lead to a constant signal from the vertical flow. Our measurement of this quantity for the average supergranule, 5.1 s, is constant over the distance range. This magnitude of signal cannot be caused by the level of upflow at cell centers seen at the photosphere of 10 m/s extended in depth. It requires the vertical flow to increase with depth. A simple Gaussian model of the increase with depth implies a peak upward flow of 240 m/s at a depth of 2.3 Mm and a peak horizontal flow of 700 m/s at a depth of 1.6 Mm.

46 CFR 10.412 - Distance and e-learning.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Distance and e-learning. 10.412 Section 10.412 Shipping... CREDENTIAL Training Courses and Programs § 10.412 Distance and e-learning. The Coast Guard may allow the training of mariners by means of distance learning and e-learning in accordance with the standards of...

Self-Regulated Learning Ability of Chinese Distance Learners

ERIC Educational Resources Information Center

Zhao, Hong; Chen, Li; Panda, Santosh

2014-01-01

This study reports on self-regulated learning (SRL) of Chinese distance learners by using a structured SRL scale. SRL of adult and lifelong learners is a well-researched area, though its application within distance education is a new area of investigation. Open and distance learning lean heavily on self-learning and self-learning resources, though…

Distance Education via the Internet (Methodology and Results).

ERIC Educational Resources Information Center

Verbrugge, William

While Purdue University Calumet (PUC) (Hammond, Indiana) has been a receiver of distance education for a number of years, a number of faculty expressed interest in developing courseware that would allow PUC to be a provider. After a distance education mission statement and goals were outlined, a pilot course was established. The distance education…

Development of the table of initial isolation distances and protective action distances for the 2004 emergency response guidebook.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, D. F.; Freeman, W. A.; Carhart, R. A.

2005-09-23

This report provides technical documentation for values in the Table of Initial Isolation and Protective Action Distances (PADs) in the 2004 Emergency Response Guidebook (ERG2004). The objective for choosing the PADs specified in the ERG2004 is to balance the need to adequately protect the public from exposure to potentially harmful substances against the risks and expenses that could result from overreacting to a spill. To quantify this balance, a statistical approach is adopted, whereby the best available information is used to conduct an accident scenario analysis and develop a set of up to 1,000,000 hypothetical incidents. The set accounts formore » differences in containers types, incident types, accident severity (i.e., amounts released), locations, times of day, times of year, and meteorological conditions. Each scenario is analyzed using detailed emission rate and atmospheric dispersion models to calculate the downwind chemical concentrations from which a 'safe distance' is determined. The safe distance is defined as the distance downwind from the source at which the chemical concentration falls below health protection criteria. The American Industrial Hygiene Association's Emergency Response Planning Guideline Level 2 (ERPG-2) or equivalent is the health criteria used. The statistical sample of safe distance values for all incidents considered in the analysis are separated into four categories: small spill/daytime release, small spill/nighttime release, large spill/daytime release, and large spill/nighttime release. The 90th-percentile safe distance values for each of these groups became the PADs that appear in the ERG2004.« less

Long working distance interference microscope

DOEpatents

Sinclair, Michael B.; DeBoer, Maarten P.; Smith, Norman F.

2004-04-13

Disclosed is a long working distance interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. The long working distance of 10-30 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-D height profiles of MEMS test structures to be acquired across an entire wafer. A well-matched pair of reference/sample objectives is not required, significantly reducing the cost of this microscope, as compared to a Linnik microinterferometer.

Going the Distance.

ERIC Educational Resources Information Center

Ambler, Marjane

1994-01-01

Describes efforts to utilize advances in telecommunications technology to provide distance education for tribal colleges that reflects tribal cultures. Indicates that planners have decided to establish uplinks at the colleges, instead of merely downlinks from remote sites, and that satellite technology will be utilized to reach as many…

Personalizing Distance Learning

ERIC Educational Resources Information Center

Coombs-Richardson, Rita

2007-01-01

This article discusses how a personal approach to online learning can yield a successful experience for adults earning advanced degrees or certification in teaching. Distance learning has become increasingly popular among learners with family and work obligations. Degree-seeking adult learners appreciate the flexibility and convenience of learning…

Single-Image Distance Measurement by a Smart Mobile Device.

PubMed

Chen, Shangwen; Fang, Xianyong; Shen, Jianbing; Wang, Linbo; Shao, Ling

2017-12-01

Existing distance measurement methods either require multiple images and special photographing poses or only measure the height with a special view configuration. We propose a novel image-based method that can measure various types of distance from single image captured by a smart mobile device. The embedded accelerometer is used to determine the view orientation of the device. Consequently, pixels can be back-projected to the ground, thanks to the efficient calibration method using two known distances. Then the distance in pixel is transformed to a real distance in centimeter with a linear model parameterized by the magnification ratio. Various types of distance specified in the image can be computed accordingly. Experimental results demonstrate the effectiveness of the proposed method.

Remote logo detection using angle-distance histograms

NASA Astrophysics Data System (ADS)

Youn, Sungwook; Ok, Jiheon; Baek, Sangwook; Woo, Seongyoun; Lee, Chulhee

2016-05-01

Among all the various computer vision applications, automatic logo recognition has drawn great interest from industry as well as various academic institutions. In this paper, we propose an angle-distance map, which we used to develop a robust logo detection algorithm. The proposed angle-distance histogram is invariant against scale and rotation. The proposed method first used shape information and color characteristics to find the candidate regions and then applied the angle-distance histogram. Experiments show that the proposed method detected logos of various sizes and orientations.

Male and female contributions to behavioral isolation in darters as a function of genetic distance and color distance

PubMed Central

Moran, Rachel L.; Zhou, Muchu; Catchen, Julian M.; Fuller, Rebecca C.

2017-01-01

Abstract Determining which reproductive isolating barriers arise first between geographically isolated lineages is critical to understanding allopatric speciation. We examined behavioral isolation among four recently diverged allopatric species in the orangethroat darter clade (Etheostoma: Ceasia). We also examined behavioral isolation between each Ceasia species and the sympatric rainbow darter Etheostoma caeruleum. We asked (1) is behavioral isolation present between allopatric Ceasia species, and how does this compare to behavioral isolation with E. caeruleum, (2) does male color distance and/or genetic distance predict behavioral isolation between species, and (3) what are the relative contributions of female choice, male choice, and male competition to behavioral isolation? We found that behavioral isolation, genetic differentiation, and male color pattern differentiation were present between allopatric Ceasia species. Males, but not females, discerned between conspecific and heterospecific mates. Males also directed more aggression toward conspecific rival males. The high levels of behavioral isolation among Ceasia species showed no obvious pattern with genetic distance or male color distance. However, when the E. caeruleum was included in the analysis, an association between male aggression and male color distance was apparent. We discuss the possibility that reinforcement between Ceasia and E. caeruleum is driving behavioral isolation among allopatric Ceasia species. PMID:28776645

Digital Compass Learning: Distance Education Enrollment Report 2017

ERIC Educational Resources Information Center

Allen, I. Elaine; Seaman, Jeff

2017-01-01

This study takes a detailed look at the trends and patterns of distance education enrollments among U.S. degree-granting higher education institutions. Distance education continued its pattern of growth for yet another year. Fall 2015 saw more than 6 million students taking at least one distance course, having increased by 3.9% over the previous…

Distance telescopes: a survey of user success.

PubMed

Lowe, J B; Rubinstein, M P

2000-05-01

The distance telescope has a historical reputation for causing difficulties in prescribing and adaptation. Hence, we considered that a retrospective survey of patients at Nottingham Low Vision Clinic might elucidate specific attributes that influence an individual patient's success in using a distance telescope. From 142 patients prescribed distance telescopes since the Clinic's inception, 133 apparently remained users and were mailed a preliminary three-question enquiry about usage of their distance telescopes. The 87 respondents were followed up with questionnaire 2, requesting explicit information about usage, namely frequency, degree of ease or difficulty, and purpose. Older patients required higher magnification (p < 0.025). Seventeen of 74 respondents to questionnaire 2 had various adaptational problems, which are discussed; 57 of 74 patients found their distance telescopes easy to use, and 49 of 57 were frequent users. Thus, ease and frequency are linked (p < 0.05). People tended to use their distance telescopes outdoors and indoors with similar frequency (p > or = 0.29). Adaptation was found to be unrelated to visual acuity, binocularity/monocularity, ocular pathology, or restricted mobility; magnification seemed to be influential, although not significantly. Aging did not significantly impede adaptation. We infer that the universal criterion for selecting treatable patients seems to be personality type. We conclude that adaptation to a device is dependent upon active recognition of its benefits, paralleled with a tolerance of its constraints, which combine to make usage easy and regular on at least one common task.

Perspective Space as a Model for Distance and Size Perception.

PubMed

Erkelens, Casper J

2017-01-01

In the literature, perspective space has been introduced as a model of visual space. Perspective space is grounded on the perspective nature of visual space during both binocular and monocular vision. A single parameter, that is, the distance of the vanishing point, transforms the geometry of physical space into that of perspective space. The perspective-space model predicts perceived angles, distances, and sizes. The model is compared with other models for distance and size perception. Perspective space predicts that perceived distance and size as a function of physical distance are described by hyperbolic functions. Alternatively, power functions have been widely used to describe perceived distance and size. Comparison of power and hyperbolic functions shows that both functions are equivalent within the range of distances that have been judged in experiments. Two models describing perceived distance on the ground plane appear to be equivalent with the perspective-space model too. The conclusion is that perspective space unifies a number of models of distance and size perception.

Perspective Space as a Model for Distance and Size Perception

PubMed Central

2017-01-01

In the literature, perspective space has been introduced as a model of visual space. Perspective space is grounded on the perspective nature of visual space during both binocular and monocular vision. A single parameter, that is, the distance of the vanishing point, transforms the geometry of physical space into that of perspective space. The perspective-space model predicts perceived angles, distances, and sizes. The model is compared with other models for distance and size perception. Perspective space predicts that perceived distance and size as a function of physical distance are described by hyperbolic functions. Alternatively, power functions have been widely used to describe perceived distance and size. Comparison of power and hyperbolic functions shows that both functions are equivalent within the range of distances that have been judged in experiments. Two models describing perceived distance on the ground plane appear to be equivalent with the perspective-space model too. The conclusion is that perspective space unifies a number of models of distance and size perception. PMID:29225765

Refocusing distance of a standard plenoptic camera.

PubMed

Hahne, Christopher; Aggoun, Amar; Velisavljevic, Vladan; Fiebig, Susanne; Pesch, Matthias

2016-09-19

Recent developments in computational photography enabled variation of the optical focus of a plenoptic camera after image exposure, also known as refocusing. Existing ray models in the field simplify the camera's complexity for the purpose of image and depth map enhancement, but fail to satisfyingly predict the distance to which a photograph is refocused. By treating a pair of light rays as a system of linear functions, it will be shown in this paper that its solution yields an intersection indicating the distance to a refocused object plane. Experimental work is conducted with different lenses and focus settings while comparing distance estimates with a stack of refocused photographs for which a blur metric has been devised. Quantitative assessments over a 24 m distance range suggest that predictions deviate by less than 0.35 % in comparison to an optical design software. The proposed refocusing estimator assists in predicting object distances just as in the prototyping stage of plenoptic cameras and will be an essential feature in applications demanding high precision in synthetic focus or where depth map recovery is done by analyzing a stack of refocused photographs.

Ultraluminous X-ray sources: new distance indicators?

NASA Astrophysics Data System (ADS)

Różańska, A.; Bresler, K.; Bełdycki, B.; Madej, J.; Adhikari, T. P.

2018-05-01

Aims: In this paper we fit the NuSTAR and XMM-Newton data of three sources: NGC 7793 P13, NGC5907 ULX1, and Circinus ULX5. Methods: Our single model contains emission from a non-spherical system: a neutron star plus an accretion disk directed towards the observer. Results: We obtained a very good fit with the reduced χ2 per degree of freedom equal to 1.08 for P13, 1.01 for ULX1, and 1.14 for ULX5. The normalization of our model constrains the distance to the source. The resulting distances are D = 3.41-0.10+0.11, 6.55-0.81+0.69, and 2.60-0.03+0.05 Mpc for P13, ULX1, and ULX5 respectively. The distances to P13 and ULX5 are in perfect agreement with previous distance measurements to their host galaxies. Conclusions: Our results confirm that P13, ULX1, and ULX5 may contain central hot neutron stars. When the outgoing emission is computed by integration over the emitting surface and successfully fitted to the data, then the resulting model normalization is the direct distance indicator.

The role of vision in auditory distance perception.

PubMed

Calcagno, Esteban R; Abregú, Ezequiel L; Eguía, Manuel C; Vergara, Ramiro

2012-01-01

In humans, multisensory interaction is an important strategy for improving the detection of stimuli of different nature and reducing the variability of response. It is known that the presence of visual information affects the auditory perception in the horizontal plane (azimuth), but there are few researches that study the influence of vision in the auditory distance perception. In general, the data obtained from these studies are contradictory and do not completely define the way in which visual cues affect the apparent distance of a sound source. Here psychophysical experiments on auditory distance perception in humans are performed, including and excluding visual cues. The results show that the apparent distance from the source is affected by the presence of visual information and that subjects can store in their memory a representation of the environment that later improves the perception of distance.

Distance Education in Southern Africa Conference, 1987. Papers 4.2: Professional Education and Practical Training at a Distance.

ERIC Educational Resources Information Center

Adey, David, Comp.; And Others

Fifteen papers from the University of South Africa's Conference on Distance Education are presented on professional education and practical training. They include: "The Art Work: From Concept to Realization" (Leon du Plessis and Koos van der Watt); "Distance Education for Industrial, Professional, and Practical Training" (Jacob…

Prenatal Anogenital Distance Is Shorter in Fetuses With Hypospadias.

PubMed

Gilboa, Yinon; Perlman, Sharon; Kivilevitch, Zvi; Messing, Baruch; Achiron, Reuven

2017-01-01

Recent research provides evidence that anogenital distance may serve as a novel metric to assess reproductive potential in men. In children, a shorter anogenital distance was linked with cryptorchidism, hypospadias, and micropenis. Scarce data exist in the literature regarding anogenital distance measurement in the fetus. The aim of our study was to assess whether intrauterine measurement of fetal anogenital distance could assist in the differential diagnosis of male genital anomalies. Anogenital distance was prospectively measured in all cases referred for suspected isolated abnormal male genitalia. Final diagnoses, confirmed by a pediatric urologist, were compared with anogenital distance prenatal measurements. Fifty-two cases were referred for evaluation because of suspected male external genital malformation during a 12-month period. Cases with normal-appearing genitalia, associated major malformations, and early severe fetal growth restriction were excluded from the study. Postnatal examination revealed 14 cases of hypospadias in varying severity and 8 cases of a buried penis. All fetuses with hypospadias had an anogenital distance measurement below the fifth percentile. Statistical analysis revealed a significant difference between the normal mean anogenital distance for gestational age versus those with hypospadias (mean ± SD, 16.90 ± 4.08 and 11.68 ± 3.31 mm, respectively; P = .001). No significant difference was found between the normal mean anogenital distance for gestational age versus those with a buried penis (18.85 ± 2.76 and 19.46 ± 3.41 mm; P = .700). Fetuses with hypospadias have a statistically significant shorter anogenital distance compared with the general population. Therefore, anogenital distance may serve as a complementary objective sonographic parameter in the prenatal assessment and counseling of male external genital anomalies. © 2016 by the American Institute of Ultrasound in Medicine.

Learning across Distance

ERIC Educational Resources Information Center

Cowan, Kristina

2009-01-01

A 2008 report, "Keeping Pace with K-12 Online Learning," commissioned by North American Council for Online Learning (NACOL) and others, defines online learning as "teacher-led education that takes place over the Internet, with the teacher and student separated geographically." The term "distance learning" includes online education, but is…

Long Distance Learning.

ERIC Educational Resources Information Center

Villeneuve, Phyllis, Ed.

1997-01-01

This report, from the Faculty Association of Community and Technical Colleges (FACTC) in Washington, focuses on various distance learning courses offered by the state's two-year colleges. The report contains 16 articles from faculty members and students, including: (1) "The Emperor's New Tutor: A Confession" (Sydney Wallace Stegall); (2)…

Climbing the Cosmic Distance Ladder Artist Concept

NASA Image and Video Library

2012-10-03

Astronomers using NASA Spitzer Space Telescope have greatly improved the cosmic distance ladder used to measure the expansion rate of the universe, its size and age. This artist concept symbolically shows a series of stars that have known distances.

Application of Distance Learning Technology to Strategic Education.

DTIC Science & Technology

1996-02-26

service or government agency. STRATEGY RESEARCH PROJECT APPLICATION OF DISTANCE LEARNING TECHNOLOGY TO STRATEGIC EDUCATION BY LIEUTENANT COLONEL...APPLICATION OF DISTANCE LEARNING TECHNOLOGY TO STRATEGIC EDUCATION by Lieutenant Colonel Greig W. Mitchell United States Army Commander David M...distance learning technology can also enhance the functions of research and public service. The purpose of research programs in higher education is

Limited sight distance warning for vertical curves

DOT National Transportation Integrated Search

1984-11-01

This is a summary of the procedures and findings of a study of highway signs to warn of restricted sight distance due to crest vertical curves. Driver awareness, understanding, and response to the existing LIMITED SIGHT DISTANCE (LSD) sign and severa...

Subsurface Supergranular Vertical Flows as Measured Using Large Distance Separations in Time-Distance Helioseismology

NASA Technical Reports Server (NTRS)

Duvall, Thomas L., Jr.; Hanasoge, S. M.

2012-01-01

As large-distance rays (say, 10 - 24deg) approach the solar surface approximately vertically, travel times measured from surface pairs for these large separations are mostly sensitive to vertical flows, at least for shallow flows within a few Mm of the solar surface. All previous analyses of supergranulation have used smaller separations and have been hampered by the difficulty of separating the horizontal and vertical flow components. We find that the large-separation travel times associated with supergranulation cannot be studied using the standard phase-speed filters of time-distance helioseismology. These filters, whose use is based upon a refractive model of the perturbations, reduce the resultant travel time signal by at least an order of magnitude at some distances. More effective filters are derived. Modeling suggests that the center-annulus travel-time difference [outward-going time minus inward-going time] in the separation range delta= 10 - 24deg is insensitive to the horizontally diverging flow from the centers of the supergranules and should lead to a constant signal from the vertical flow. Our measurement of this quantity, 5.1+/-0.1 seconds, is constant over the distance range. This magnitude of the signal cannot be caused by the level of upflow at cell centers seen at the photosphere of 10 ms(exp-1) extended in depth. It requires the vertical flow to increase with depth. A simple Gaussian model of the increase with depth implies a peak upward flow of 240 ms(exp-1) at a depth of 2.3 Mm and a peak horizontal flow of 700 ms(exp-1) at a depth of 1.6 Mm.

Probabilistic determination of probe locations from distance data

PubMed Central

Xu, Xiao-Ping; Slaughter, Brian D.; Volkmann, Niels

2013-01-01

Distance constraints, in principle, can be employed to determine information about the location of probes within a three-dimensional volume. Traditional methods for locating probes from distance constraints involve optimization of scoring functions that measure how well the probe location fits the distance data, exploring only a small subset of the scoring function landscape in the process. These methods are not guaranteed to find the global optimum and provide no means to relate the identified optimum to all other optima in scoring space. Here, we introduce a method for the location of probes from distance information that is based on probability calculus. This method allows exploration of the entire scoring space by directly combining probability functions representing the distance data and information about attachment sites. The approach is guaranteed to identify the global optimum and enables the derivation of confidence intervals for the probe location as well as statistical quantification of ambiguities. We apply the method to determine the location of a fluorescence probe using distances derived by FRET and show that the resulting location matches that independently derived by electron microscopy. PMID:23770585

Femtosecond frequency comb based distance measurement in air.

PubMed

Balling, Petr; Kren, Petr; Masika, Pavel; van den Berg, S A

2009-05-25

Interferometric measurement of distance using a femtosecond frequency comb is demonstrated and compared with a counting interferometer displacement measurement. A numerical model of pulse propagation in air is developed and the results are compared with experimental data for short distances. The relative agreement for distance measurement in known laboratory conditions is better than 10(-7). According to the model, similar precision seems feasible even for long-distance measurement in air if conditions are sufficiently known. It is demonstrated that the relative width of the interferogram envelope even decreases with the measured length, and a fringe contrast higher than 90% could be obtained for kilometer distances in air, if optimal spectral width for that length and wavelength is used. The possibility of comb radiation delivery to the interferometer by an optical fiber is shown by model and experiment, which is important from a practical point of view.

Distance still matters. The hard reality of global expansion.

PubMed

Ghemawat, P

2001-09-01

Companies routinely overestimate the attractiveness of foreign markets. Dazzled by the sheer size of untapped markets, they lose sight of the difficulties of pioneering new, often very different territories. The problem is rooted in the analytic tools (the most prominent being country portfolio analysis, or CPA) that managers use to judge international investments. By focusing on national wealth, consumer income, and people's propensity to consume, CPA emphasizes potential sales, ignoring the costs and risks of doing business in a new market. Most of these costs and risks result from the barriers created by distance. "Distance," however, does not refer only to geography; its other dimensions can make foreign markets considerably more or less attractive. The CAGE framework of distance presented here considers four attributes: cultural distance (religious beliefs, race, social norms, and language that are different for the target country and the country of the company considering expansion); administrative or political distance (colony-colonizer links, common currency, and trade arrangements); geographic distance (the physical distance between the two countries, the size of the target country, access to waterways and the ocean, internal topography, and transportation and communications infrastructures); and economic distance (disparities in the two countries' wealth or consumer income and variations in the cost and quality of financial and other resources). This framework can help to identify the ways in which potential markets may be distant from existing ones. The article explores how (and by how much) various types of distance can affect different types of industries and shows how dramatically an explicit consideration of distance can change a company's picture of its strategic options.

A distance-controlled nanoparticle array using PEGylated ferritin

NASA Astrophysics Data System (ADS)

He, Chao; Uenuma, Mutsunori; Okamoto, Naofumi; Kamitake, Hiroki; Ishikawa, Yasuaki; Yamashita, Ichiro; Uraoka, Yukiharu

2014-12-01

A distance-controlled nanoparticle (NP) array was investigated using a simple spin coating process. It was found that the separation distance of NPs was controlled at the nanoscale by using polyethylene glycols (PEGs). Ferritin was used to synthesize NPs and carry them to a substrate by using the different molecular weight of PEGs. In order to control the distance of the NPs, PEGs with molecular weights of 2k, 5k, 10k and 20k were modified on ferritin with 10 mM ion strength and 0.01 mg ml-1 ferritin concentration. The separated distances of NPs increased along with increase in PEG molecular weight.

Audiovisual Delay as a Novel Cue to Visual Distance.

PubMed

Jaekl, Philip; Seidlitz, Jakob; Harris, Laurence R; Tadin, Duje

2015-01-01

For audiovisual sensory events, sound arrives with a delay relative to light that increases with event distance. It is unknown, however, whether humans can use these ubiquitous sound delays as an information source for distance computation. Here, we tested the hypothesis that audiovisual delays can both bias and improve human perceptual distance discrimination, such that visual stimuli paired with auditory delays are perceived as more distant and are thereby an ordinal distance cue. In two experiments, participants judged the relative distance of two repetitively displayed three-dimensional dot clusters, both presented with sounds of varying delays. In the first experiment, dot clusters presented with a sound delay were judged to be more distant than dot clusters paired with equivalent sound leads. In the second experiment, we confirmed that the presence of a sound delay was sufficient to cause stimuli to appear as more distant. Additionally, we found that ecologically congruent pairing of more distant events with a sound delay resulted in an increase in the precision of distance judgments. A control experiment determined that the sound delay duration influencing these distance judgments was not detectable, thereby eliminating decision-level influence. In sum, we present evidence that audiovisual delays can be an ordinal cue to visual distance.

The visual perception of size and distance.

DOT National Transportation Integrated Search

1962-07-01

The perception of absolute distance has been assumed to be important in the perception of the size of objects and the depth between them. A different hypothesis is proposed. It is asserted that perceived relative size and distance are the primary psy...

The Viability of Distance Education Science Laboratories.

ERIC Educational Resources Information Center

Forinash, Kyle; Wisman, Raymond

2001-01-01

Discusses the effectiveness of offering science laboratories via distance education. Explains current delivery technologies, including computer simulations, videos, and laboratory kits sent to students; pros and cons of distance labs; the use of spreadsheets; and possibilities for new science education models. (LRW)

More than Fiber: Distance Education in Iowa.

ERIC Educational Resources Information Center

Simonson, Michael; Schlosser, Charles

1995-01-01

Describes distance education programs in Iowa, including the Iowa Distance Education Alliance developed through the Department of Education's Star Schools Program; the use of fiber optic technology; and the Iowa Communications Network that links colleges, universities, and secondary schools with public television. (LRW)

Finally! Distance Education for Library Support Staff.

ERIC Educational Resources Information Center

Rau, Kirk

1998-01-01

Discusses distance undergraduate education programs for paraprofessional librarians and suggests how to evaluate institutions: accreditation, academic program, communication, curriculum, and delivery methods. Highlights the AS degree in Library and Information Technology distance-education program offered by the University of Maine at Augusta.…

Deep-Focusing Time-Distance Helioseismology

NASA Technical Reports Server (NTRS)

Duvall, T. L., Jr.; Jensen, J. M.; Kosovichev, A. G.; Birch, A. C.; Fisher, Richard R. (Technical Monitor)

2001-01-01

Much progress has been made by measuring the travel times of solar acoustic waves from a central surface location to points at equal arc distance away. Depth information is obtained from the range of arc distances examined, with the larger distances revealing the deeper layers. This method we will call surface-focusing, as the common point, or focus, is at the surface. To obtain a clearer picture of the subsurface region, it would, no doubt, be better to focus on points below the surface. Our first attempt to do this used the ray theory to pick surface location pairs that would focus on a particular subsurface point. This is not the ideal procedure, as Born approximation kernels suggest that this focus should have zero sensitivity to sound speed inhomogeneities. However, the sensitivity is concentrated below the surface in a much better way than the old surface-focusing method, and so we expect the deep-focusing method to be more sensitive. A large sunspot group was studied by both methods. Inversions based on both methods will be compared.

Correlation function of the luminosity distances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biern, Sang Gyu; Yoo, Jaiyul, E-mail: sgbiern@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch

We present the correlation function of the luminosity distances in a flat ΛCDM universe. Decomposing the luminosity distance fluctuation into the velocity, the gravitational potential, and the lensing contributions in linear perturbation theory, we study their individual contributions to the correlation function. The lensing contribution is important at large redshift ( z ∼> 0.5) but only for small angular separation (θ ∼< 3°), while the velocity contribution dominates over the other contributions at low redshift or at larger separation. However, the gravitational potential contribution is always subdominant at all scale, if the correct gauge-invariant expression is used. The correlation functionmore » of the luminosity distances depends significantly on the matter content, especially for the lensing contribution, thus providing a novel tool of estimating cosmological parameters.« less

On the rank-distance median of 3 permutations.

PubMed

Chindelevitch, Leonid; Pereira Zanetti, João Paulo; Meidanis, João

2018-05-08

Recently, Pereira Zanetti, Biller and Meidanis have proposed a new definition of a rearrangement distance between genomes. In this formulation, each genome is represented as a matrix, and the distance d is the rank distance between these matrices. Although defined in terms of matrices, the rank distance is equal to the minimum total weight of a series of weighted operations that leads from one genome to the other, including inversions, translocations, transpositions, and others. The computational complexity of the median-of-three problem according to this distance is currently unknown. The genome matrices are a special kind of permutation matrices, which we study in this paper. In their paper, the authors provide an [Formula: see text] algorithm for determining three candidate medians, prove the tight approximation ratio [Formula: see text], and provide a sufficient condition for their candidates to be true medians. They also conduct some experiments that suggest that their method is accurate on simulated and real data. In this paper, we extend their results and provide the following: Three invariants characterizing the problem of finding the median of 3 matrices A sufficient condition for uniqueness of medians that can be checked in O(n) A faster, [Formula: see text] algorithm for determining the median under this condition A new heuristic algorithm for this problem based on compressed sensing A [Formula: see text] algorithm that exactly solves the problem when the inputs are orthogonal matrices, a class that includes both permutations and genomes as special cases. Our work provides the first proof that, with respect to the rank distance, the problem of finding the median of 3 genomes, as well as the median of 3 permutations, is exactly solvable in polynomial time, a result which should be contrasted with its NP-hardness for the DCJ (double cut-and-join) distance and most other families of genome rearrangement operations. This result, backed by our experimental

Developing Transactional Distance Scale and Examining Transactional Distance Perception of Blended Learning Students in Terms of Different Variables

ERIC Educational Resources Information Center

Horzum, Mehmet Baris

2011-01-01

The first purpose of this study was to develop valid and reliable a scale which measure the transactional distance. Besides, the second purpose of the study was to investigate whether the transactional distance perception differed according to gender, utilized component and number of logins to system, and also blended learning was useful. The…

Distance Education in Taiwan: A Model Validated.

ERIC Educational Resources Information Center

Shih, Mei-Yau; Zvacek, Susan M.

The Triad Perspective Model of Distance Education (TPMDE) guides researchers in developing research questions, gathering data, and producing a comprehensive description of a distance education program. It was developed around three theoretical perspectives: (1) curriculum development theory (Tyler's four questions, 1949); (2) systems theory…

Measuring Distances to Remote Galaxies and Quasars.

ERIC Educational Resources Information Center

McCarthy, Patrick J.

1988-01-01

Describes the use of spectroscopy and the redshift to measure how far an object is by measuring how fast it is receding from earth. Lists the most distant quasars yet found. Tables include "Redshift vs. Distance" and "Distances to Celestial Objects for Various Cosmologies." (CW)

Collaboration in Distance Education. International Case Studies.

ERIC Educational Resources Information Center

Moran, Louise, Ed.; Mugridge, Ian, Ed.

This book contains nine case studies of collaboration in distance education. The case studies focus on such aspects of collaboration in distance education as the following: roles of individual institutional partners; importance of personal relationships; benefits of collaboration to individual partners; conflicts between collaboration and…

Time-Distance Helioseismology

NASA Technical Reports Server (NTRS)

Duvall, Thomas L., Jr.

2010-01-01

Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

A Distance Measure for Genome Phylogenetic Analysis

NASA Astrophysics Data System (ADS)

Cao, Minh Duc; Allison, Lloyd; Dix, Trevor

Phylogenetic analyses of species based on single genes or parts of the genomes are often inconsistent because of factors such as variable rates of evolution and horizontal gene transfer. The availability of more and more sequenced genomes allows phylogeny construction from complete genomes that is less sensitive to such inconsistency. For such long sequences, construction methods like maximum parsimony and maximum likelihood are often not possible due to their intensive computational requirement. Another class of tree construction methods, namely distance-based methods, require a measure of distances between any two genomes. Some measures such as evolutionary edit distance of gene order and gene content are computational expensive or do not perform well when the gene content of the organisms are similar. This study presents an information theoretic measure of genetic distances between genomes based on the biological compression algorithm expert model. We demonstrate that our distance measure can be applied to reconstruct the consensus phylogenetic tree of a number of Plasmodium parasites from their genomes, the statistical bias of which would mislead conventional analysis methods. Our approach is also used to successfully construct a plausible evolutionary tree for the γ-Proteobacteria group whose genomes are known to contain many horizontally transferred genes.

Quantum-limited heat conduction over macroscopic distances

NASA Astrophysics Data System (ADS)

Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko

2016-05-01

The emerging quantum technological apparatuses, such as the quantum computer, call for extreme performance in thermal engineering. Cold distant heat sinks are needed for the quantized electric degrees of freedom owing to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance. However, the short distance between the heat-exchanging bodies in the previous experiments hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics, which provides a basis for the superconducting quantum computer. Especially, our results facilitate remote cooling of nanoelectronic devices using faraway in situ-tunable heat sinks. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications.

Distance Learning: What's Holding Back This Boundless Delivery System?

ERIC Educational Resources Information Center

Bruder, Isabelle

1989-01-01

Discusses distance learning, identifies who distance learners may be, and examines issues involved in establishing distance learning systems. Topics discussed include teacher concerns, including job security and certification; curriculum concerns, including state and local requirements and cross-cultural issues; cooperative development,…

Why Do Long-Distance Travelers Have Improved Pancreatectomy Outcomes?

PubMed

Jindal, Manila; Zheng, Chaoyi; Quadri, Humair S; Ihemelandu, Chukwuemeka U; Hong, Young K; Smith, Andrew K; Dudeja, Vikas; Shara, Nawar M; Johnson, Lynt B; Al-Refaie, Waddah B

2017-08-01

Centralization of complex surgical care has led patients to travel longer distances. Emerging evidence suggested a negative association between increased travel distance and mortality after pancreatectomy. However, the reason for this association remains largely unknown. We sought to unravel the relationships among travel distance, receiving pancreatectomy at high-volume hospitals, delayed surgery, and operative outcomes. We identified 44,476 patients who underwent pancreatectomy for neoplasms between 2004 and 2013 at the reporting facility from the National Cancer Database. Multivariable analyses were performed to examine the independent relationships between increments in travel distance mortality (30-day and long-term survival) after adjusting for patient demographics, comorbidity, cancer stage, and time trend. We then examined how additional adjustment of procedure volume affected this relationship overall and among rural patients. Median travel distance to undergo pancreatectomy increased from 16.5 to 18.7 miles (p for trend < 0.001). Although longer travel distance was associated with delayed pancreatectomy, it was also related to higher odds of receiving pancreatectomy at a high-volume hospital and lower postoperative mortality. In multivariable analysis, difference in mortality among patients with varying travel distance was attenuated by adjustment for procedure volume. However, longest travel distance was still associated with a 77% lower 30-day mortality rate than shortest travel among rural patients, even when accounting for procedure volume. Our large national study found that the beneficial effect of longer travel distance on mortality after pancreatectomy is mainly attributable to increase in procedure volume. However, it can have additional benefits on rural patients that are not explained by volume. Distance can represent a surrogate for rural populations. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights

Distance Learning for Teacher Training in Brazil

ERIC Educational Resources Information Center

Bof, Alvana Maria

2004-01-01

Proformacao is a distance teacher certification course aimed at providing training to 27,000 uncertified teachers in 15 Brazilian states. This innovative program organizes human and technical resources for delivering distance education in a cost-effective manner. Different from other institutional systems--which typically employ their own…

Research on Distance Education Development in China

ERIC Educational Resources Information Center

Xin, Ding; Jian, Niu; Yanhui, Han

2010-01-01

Distance education is among the significant fields for the application of educational technology. Distance education in China has gone through three phases, namely: correspondence-based education, radio and TV-based education and online education. This paper was based on educational technology application, and the historical, dialectic and…

What Does Electronic Conferencing Afford Distance Education?

ERIC Educational Resources Information Center

Barnes, Sally

2000-01-01

Discusses the use of technology for distance learning in higher education and examines the similarities and differences between face-to-face seminars and online discussions. Considers the concept of affordance in relation to information and communication technologies and distance education; and examines affordances of electronic conferencing and…

Distance Education at Memorial University of Newfoundland.

ERIC Educational Resources Information Center

Keough, Erin

This presentation describes the distance education program at Memorial University (Newfoundland), which operates the Telemedicine Centre, including an audiographic, teleconference network that uses a combination of hardware and software to turn an MS DOS computer into an interactive long distance blackboard. Topics covered by the presentation…

Instructor and Student Attitudes Toward Distance Learning.

ERIC Educational Resources Information Center

Inman, Elliot; Kerwin, Michael; Mayes, Larry

1999-01-01

Discusses data collected from 11 distance-learning classes. The instructors were willing to teach distance-learning classes again, but said the courses were of equal or lesser quality than traditional classes. The 334 students surveyed were highly satisfied with the courses and instructors. Contains 17 references. (TGO)

Field evaluation of distance-estimation error during wetland-dependent bird surveys

USGS Publications Warehouse

Nadeau, Christopher P.; Conway, Courtney J.

2012-01-01

Context: The most common methods to estimate detection probability during avian point-count surveys involve recording a distance between the survey point and individual birds detected during the survey period. Accurately measuring or estimating distance is an important assumption of these methods; however, this assumption is rarely tested in the context of aural avian point-count surveys. Aims: We expand on recent bird-simulation studies to document the error associated with estimating distance to calling birds in a wetland ecosystem. Methods: We used two approaches to estimate the error associated with five surveyor's distance estimates between the survey point and calling birds, and to determine the factors that affect a surveyor's ability to estimate distance. Key results: We observed biased and imprecise distance estimates when estimating distance to simulated birds in a point-count scenario (x̄error = -9 m, s.d.error = 47 m) and when estimating distances to real birds during field trials (x̄error = 39 m, s.d.error = 79 m). The amount of bias and precision in distance estimates differed among surveyors; surveyors with more training and experience were less biased and more precise when estimating distance to both real and simulated birds. Three environmental factors were important in explaining the error associated with distance estimates, including the measured distance from the bird to the surveyor, the volume of the call and the species of bird. Surveyors tended to make large overestimations to birds close to the survey point, which is an especially serious error in distance sampling. Conclusions: Our results suggest that distance-estimation error is prevalent, but surveyor training may be the easiest way to reduce distance-estimation error. Implications: The present study has demonstrated how relatively simple field trials can be used to estimate the error associated with distance estimates used to estimate detection probability during avian point

Occasional Papers in Open and Distance Learning, Number 18.

ERIC Educational Resources Information Center

Donnan, Peter, Ed.

Six papers examine innovations and trends in distance learning, frequently drawing upon empirical research or informal observations on distance learning students at Charles Sturt University (Australia). "On-Line Study Packages for Distance Education: Some Considerations of Conceptual Parameters" (Dirk M. R. Spennemann) discusses issues…

Angular Declination and the Dynamic Perception of Egocentric Distance

PubMed Central

Gajewski, Daniel A.; Philbeck, John W.; Wirtz, Philip W.; Chichka, David

2014-01-01

The extraction of the distance between an object and an observer is fast when angular declination is informative, as it is with targets placed on the ground. To what extent does angular declination drive performance when viewing time is limited? Participants judged target distances in a real-world environment with viewing durations ranging from 36–220 ms. An important role for angular declination was supported by experiments showing that the cue provides information about egocentric distance even on the very first glimpse, and that it supports a sensitive response to distance in the absence of other useful cues. Performance was better at 220 ms viewing durations than for briefer glimpses, suggesting that the perception of distance is dynamic even within the time frame of a typical eye fixation. Critically, performance in limited viewing trials was better when preceded by a 15 second preview of the room without a designated target. The results indicate that the perception of distance is powerfully shaped by memory from prior visual experience with the scene. A theoretical framework for the dynamic perception of distance is presented. PMID:24099588

Angular declination and the dynamic perception of egocentric distance.

PubMed

Gajewski, Daniel A; Philbeck, John W; Wirtz, Philip W; Chichka, David

2014-02-01

The extraction of the distance between an object and an observer is fast when angular declination is informative, as it is with targets placed on the ground. To what extent does angular declination drive performance when viewing time is limited? Participants judged target distances in a real-world environment with viewing durations ranging from 36-220 ms. An important role for angular declination was supported by experiments showing that the cue provides information about egocentric distance even on the very first glimpse, and that it supports a sensitive response to distance in the absence of other useful cues. Performance was better at 220-ms viewing durations than for briefer glimpses, suggesting that the perception of distance is dynamic even within the time frame of a typical eye fixation. Critically, performance in limited viewing trials was better when preceded by a 15-s preview of the room without a designated target. The results indicate that the perception of distance is powerfully shaped by memory from prior visual experience with the scene. A theoretical framework for the dynamic perception of distance is presented. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Listening for the Squeaky Wheel: Designing Distance Writing Program Assessment

ERIC Educational Resources Information Center

Tucker, Virginia M.

2012-01-01

Distance writing programs still struggle with assessment strategies that can evaluate student writing as well as their ability to communicate about that writing with peers at a distance. This article uses Kim, Smith and Maeng's 2008 distance education program assessment scheme to evaluate a single distance writing program at Old Dominion…

Standards of e-Learning Based Distance Education

ERIC Educational Resources Information Center

Saurabh, Kumar

2006-01-01

The term distance education is commonly used to describe courses in which nearly all the interaction between the teacher and student takes place electronically. Electronic communication may take the form of audio, video, e-mail, chat, teleconferencing, and, increasingly, the Internet. Distance education courses range from short term training…

Administration of Distance-Teaching Institutions. A Manual.

ERIC Educational Resources Information Center

Dodds, Tony, Comp.

Guidance for distance teaching media selection, management, and program organization is offered in this two-part manual. Each of eight units includes questions to be addressed, behavioral objectives, comments, exercises, and assignments. The first unit, a general introduction to distance teaching, is followed by four units covering distance…

Supporting Distance Learners for Collaborative Problem Solving.

ERIC Educational Resources Information Center

Verdejo, M. F.; Barros, B.; Abad, M. T.

This paper describes a computer-supported environment designed to facilitate distance learning through collaborative problem-solving. The goal is to encourage distance learning students to work together, in order to promote both learning of collaboration and learning through collaboration. Collaboration is defined as working together on a common…

Cornell University Library Distance Learning White Paper.

ERIC Educational Resources Information Center

Davis, Philip; Finlay, Constance; Cosgrave, Tony; McDonald, Peter

This report identifies potential issues that the Cornell University Library (CUL) might face in supporting distance learning, and recommends solutions. While the precise budgetary implications are uncertain, additional resources, services, and personnel will need to be accounted for in the cost of serving distance learners. The report addresses:…

Distance Education: Pros, Cons, and the Future.

ERIC Educational Resources Information Center

Li, Hongmei

This paper reviews recent publications on distance education and explores its promise and potential from the student's perspective, the faculty's perspective and the administrator's perspective. Findings indicate that only the self-motivated and self-disciplined students are most likely to succeed in distance education. Although the majority of…

Applying Leadership Theories to Distance Education Leadership

ERIC Educational Resources Information Center

Nworie, John

2012-01-01

The instructional delivery mode in distance education has been transitioning from the context of a physical classroom environment to a virtual learning environment or maintaining a hybrid of the two. However, most distance education programs in dual mode institutions are situated in traditional face-to-face instructional settings. Distance…

Language Distance Learning for the Digital Generation

ERIC Educational Resources Information Center

Duran-Cerda, Dolores

2010-01-01

The purpose of this article was to shed light on the potential of distance learning to overcome challenges in distance, space, time, and human and economic resources that limit access to language learning opportunities in cultural, literary, historical, geographical, and cross-cultural frames. Language and literature educators collectively have…

Student and Faculty Issues in Distance Education.

ERIC Educational Resources Information Center

Fender, David L.

Occupational safety and health faculty and occupational safety and health professionals (i.e., the potential audience for graduate level distance education programs) were surveyed to determine the considerations for a distance education-based graduate occupational safety and health program. Findings are reported related to the demand for distance…

Distance Learning in Higher Education. CHEA Update Number 3.

ERIC Educational Resources Information Center

Council for Higher Education Accreditation, Washington, DC.

This report discusses issues related to distance learning in higher education. Section 1, "The Expanding Universe of Distance Learning," examines: data from a new national survey on higher education distance learning; Internet access in elementary and secondary schools; the 1999 national survey of information technology in higher…

Distance Learning: Information Access and Services for Virtual Users.

ERIC Educational Resources Information Center

Iyer, Hemalata, Ed.

This volume centers broadly on information support services for distance education. The articles in this book can be categorized into two areas: access to information resources for distance learners, and studies of distance learning programs. Contents include: "The Challenges and Benefits of Asynchronous Learning Networks" (Daphne…

Fixation distance and fixation duration to vertical road signs.

PubMed

Costa, Marco; Simone, Andrea; Vignali, Valeria; Lantieri, Claudio; Palena, Nicola

2018-05-01

The distance of first-fixation to vertical road signs was assessed in 22 participants while driving a route of 8.34 km. Fixations to road signs were recorded by a mobile eye-movement-tracking device synchronized to GPS and kinematic data. The route included 75 road signs. First-fixation distance and fixation duration distributions were positively skewed. Median distance of first-fixation was 51 m. Median fixation duration was 137 ms with a modal value of 66 ms. First-fixation distance was linearly related to speed and fixation duration. Road signs were gazed at a much closer distance than their visibility distance. In a second study a staircase procedure was used to test the presentation-time threshold that lead to a 75% accuracy in road sign identification. The threshold was 35 ms, showing that short fixations to a road signs could lead to a correct identification. Copyright © 2018 Elsevier Ltd. All rights reserved.

VCSEL-based sensors for distance and velocity

NASA Astrophysics Data System (ADS)

Moench, Holger; Carpaij, Mark; Gerlach, Philipp; Gronenborn, Stephan; Gudde, Ralph; Hellmig, Jochen; Kolb, Johanna; van der Lee, Alexander

2016-03-01

VCSEL based sensors can measure distance and velocity in three dimensional space and are already produced in high quantities for professional and consumer applications. Several physical principles are used: VCSELs are applied as infrared illumination for surveillance cameras. High power arrays combined with imaging optics provide a uniform illumination of scenes up to a distance of several hundred meters. Time-of-flight methods use a pulsed VCSEL as light source, either with strong single pulses at low duty cycle or with pulse trains. Because of the sensitivity to background light and the strong decrease of the signal with distance several Watts of laser power are needed at a distance of up to 100m. VCSEL arrays enable power scaling and can provide very short pulses at higher power density. Applications range from extended functions in a smartphone over industrial sensors up to automotive LIDAR for driver assistance and autonomous driving. Self-mixing interference works with coherent laser photons scattered back into the cavity. It is therefore insensitive to environmental light. The method is used to measure target velocity and distance with very high accuracy at distances up to one meter. Single-mode VCSELs with integrated photodiode and grating stabilized polarization enable very compact and cost effective products. Besides the well know application as computer input device new applications with even higher accuracy or for speed over ground measurement in automobiles and up to 250km/h are investigated. All measurement methods exploit the known VCSEL properties like robustness, stability over temperature and the potential for packages with integrated optics and electronics. This makes VCSEL sensors ideally suited for new mass applications in consumer and automotive markets.

The Changeable Block Distance System Analysis

NASA Astrophysics Data System (ADS)

Lewiński, Andrzej; Toruń, Andrzej

The paper treats about efficiency analysis in Changeable Block Distance (CBD) System connected with wireless positioning and control of train. The analysis is based on modeling of typical ERTMS line and comparison with actual and future traffic. The calculations are related to assumed parameters of railway traffic corresponding to real time - table of distance Psary - Góra Włodowska from CMK line equipped in classic, ETCS Level 1 and ETCS with CBD systems.

Student Retention in Distance Education: Are We Failing Our Students?

ERIC Educational Resources Information Center

Simpson, Ormond

2013-01-01

This paper brings together some data on student retention in distance education in the form of graduation rates at a sample of distance institutions. The paper suggests that there is a "distance education deficit" with many distance institutions having less than one-quarter of the graduation rates of conventional institutions. It looks…

A New Distance Metric for Unsupervised Learning of Categorical Data.

PubMed

Jia, Hong; Cheung, Yiu-Ming; Liu, Jiming

2016-05-01

Distance metric is the basis of many learning algorithms, and its effectiveness usually has a significant influence on the learning results. In general, measuring distance for numerical data is a tractable task, but it could be a nontrivial problem for categorical data sets. This paper, therefore, presents a new distance metric for categorical data based on the characteristics of categorical values. In particular, the distance between two values from one attribute measured by this metric is determined by both the frequency probabilities of these two values and the values of other attributes that have high interdependence with the calculated one. Dynamic attribute weight is further designed to adjust the contribution of each attribute-distance to the distance between the whole data objects. Promising experimental results on different real data sets have shown the effectiveness of the proposed distance metric.

Optical Distance Measurement Device And Method Thereof

DOEpatents

Bowers, Mark W.

2004-06-15

A system and method of efficiently obtaining distance measurements of a target by scanning the target. An optical beam is provided by a light source and modulated by a frequency source. The modulated optical beam is transmitted to an acousto-optical deflector capable of changing the angle of the optical beam in a predetermined manner to produce an output for scanning the target. In operation, reflected or diffused light from the target may be received by a detector and transmitted to a controller configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

Quality Assurance, Open and Distance Learning, and Australian Universities

ERIC Educational Resources Information Center

Reid, Ian C.

2005-01-01

Open and distance education has integrated quality assurance processes since its inception. Recently, the increased use of distance teaching systems, technologies, and pedagogies by universities without a distance education heritage has enabled them to provide flexible learning opportunities. They have done this in addition to, or instead of,…

Distance Education Leaders in Latin America and the Caribbean

ERIC Educational Resources Information Center

Torres, Patrícia Lupion; Rama, Claudio

2018-01-01

Distance higher education has only relatively recently been established in some Latin American countries, as part of wider higher education reforms. The developments of distance education have been the result of sustained efforts of leading thinkers and practitioners in the region. In this article, several leading distance education professionals…

Role of Libraries in Distance Education. SPEC Kit 216.

ERIC Educational Resources Information Center

Snyder, Carolyn A., Comp.; And Others

The Systems and Procedures Exchange Center (SPEC) surveyed 119 Association of Research Libraries (ARL) members to gather information about current distance education and distance learning initiatives in ARL libraries. The objectives of the survey were to: (1) identify libraries involved in distance education activities and determine the extent or…

Distance between configurations in Markov chain Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Fukuma, Masafumi; Matsumoto, Nobuyuki; Umeda, Naoya

2017-12-01

For a given Markov chain Monte Carlo algorithm we introduce a distance between two configurations that quantifies the difficulty of transition from one configuration to the other configuration. We argue that the distance takes a universal form for the class of algorithms which generate local moves in the configuration space. We explicitly calculate the distance for the Langevin algorithm, and show that it certainly has desired and expected properties as distance. We further show that the distance for a multimodal distribution gets dramatically reduced from a large value by the introduction of a tempering method. We also argue that, when the original distribution is highly multimodal with large number of degenerate vacua, an anti-de Sitter-like geometry naturally emerges in the extended configuration space.

Support Groups in Distance Education. Knowledge Series.

ERIC Educational Resources Information Center

Robertshaw, Michael

For most distance education (DE) systems, distance, time, and/or opportunity isolate learners from their teacher and their fellow students. To facilitate interaction, most DE systems include different types of support groups. Modern technology allows groups to interact effectively even though individuals are far apart. Technology may appear to be…

Distance Education for People with Visual Impairments

ERIC Educational Resources Information Center

Liakou, Maria; Manousou, Evaggelia

2015-01-01

This paper studies the standards of higher Distance Education, focusing on the Hellenic Open University, for people who have visual impairments, so that it becomes fully accessible and thus helps reduce social exclusion. Specifically, it aims to study the operational context of Distance Education, the possibilities that modern technology provides…

Trends in Instructional Technology and Distance Education.

ERIC Educational Resources Information Center

Abromitis, Jacky

This paper discusses trends in instructional technology and distance education (ITDE). The most notable trends are the lack of funding and resources for technology training, the lack of administrative support for ITDE issues, and faculty who are reluctant to adopt technology and distance learning. This paper identifies seven emerging trends as…

36 CFR 13.604 - Wildlife distance conditions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Wildlife distance conditions. 13.604 Section 13.604 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... § 13.604 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards is...

36 CFR 13.1206 - Wildlife distance conditions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Wildlife distance conditions. 13.1206 Section 13.1206 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... Provisions § 13.1206 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards...

36 CFR 13.1206 - Wildlife distance conditions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Wildlife distance conditions. 13.1206 Section 13.1206 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... Provisions § 13.1206 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards...

36 CFR 13.604 - Wildlife distance conditions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Wildlife distance conditions. 13.604 Section 13.604 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... § 13.604 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards is...

36 CFR 13.604 - Wildlife distance conditions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Wildlife distance conditions. 13.604 Section 13.604 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... § 13.604 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards is...

36 CFR 13.1206 - Wildlife distance conditions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Wildlife distance conditions. 13.1206 Section 13.1206 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... Provisions § 13.1206 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards...

36 CFR 13.604 - Wildlife distance conditions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Wildlife distance conditions. 13.604 Section 13.604 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... § 13.604 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards is...

36 CFR 13.604 - Wildlife distance conditions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Wildlife distance conditions. 13.604 Section 13.604 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... § 13.604 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards is...

36 CFR 13.1206 - Wildlife distance conditions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Wildlife distance conditions. 13.1206 Section 13.1206 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... Provisions § 13.1206 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards...

36 CFR 13.1206 - Wildlife distance conditions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Wildlife distance conditions. 13.1206 Section 13.1206 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE... Provisions § 13.1206 Wildlife distance conditions. (a) Approaching a bear or any large mammal within 50 yards...

Distance Education: A Program and Facility Study.

ERIC Educational Resources Information Center

Holt, Malcolm; And Others

This publication provides both a review of the different technology modes that may be used for distance education and a set of guidelines for planning and developing conceptual designs for educational facilities capable of supporting technologically enhanced educational delivery systems in a variety of settings. The Distance Learning in Small…

Current and Future Demand for Distance Education.

ERIC Educational Resources Information Center

McDiarmid, G. Williamson; Goldsmith, Scott; Hill, Alexandra; Hull, Teresa

This study assesses current and future demands for distance education at the University of Alaska (UA). It highlights findings from interviews with representatives of 33 rural organizations, and 36 instructors who teach 53 distance education courses. It also lists questions raised and recommendations made by provosts at the Anchorage, Fairbanks,…

Experience(s) in Creating Distance Learning Texts

ERIC Educational Resources Information Center

Todd, Peter A.

2007-01-01

A combination of factors including longer working hours, emphasis on professional development, and increased access to the Internet have fuelled the current high demand for distance learning options in tertiary biology. Distance learner students come from a heterogeneous pool of ages, backgrounds and abilities and they require choice in how they…

Protein structure-structure alignment with discrete Fréchet distance.

PubMed

Jiang, Minghui; Xu, Ying; Zhu, Binhai

2008-02-01

Matching two geometric objects in two-dimensional (2D) and three-dimensional (3D) spaces is a central problem in computer vision, pattern recognition, and protein structure prediction. In particular, the problem of aligning two polygonal chains under translation and rotation to minimize their distance has been studied using various distance measures. It is well known that the Hausdorff distance is useful for matching two point sets, and that the Fréchet distance is a superior measure for matching two polygonal chains. The discrete Fréchet distance closely approximates the (continuous) Fréchet distance, and is a natural measure for the geometric similarity of the folded 3D structures of biomolecules such as proteins. In this paper, we present new algorithms for matching two polygonal chains in two dimensions to minimize their discrete Fréchet distance under translation and rotation, and an effective heuristic for matching two polygonal chains in three dimensions. We also describe our empirical results on the application of the discrete Fréchet distance to protein structure-structure alignment.

Approximate geodesic distances reveal biologically relevant structures in microarray data.

PubMed

Nilsson, Jens; Fioretos, Thoas; Höglund, Mattias; Fontes, Magnus

2004-04-12

Genome-wide gene expression measurements, as currently determined by the microarray technology, can be represented mathematically as points in a high-dimensional gene expression space. Genes interact with each other in regulatory networks, restricting the cellular gene expression profiles to a certain manifold, or surface, in gene expression space. To obtain knowledge about this manifold, various dimensionality reduction methods and distance metrics are used. For data points distributed on curved manifolds, a sensible distance measure would be the geodesic distance along the manifold. In this work, we examine whether an approximate geodesic distance measure captures biological similarities better than the traditionally used Euclidean distance. We computed approximate geodesic distances, determined by the Isomap algorithm, for one set of lymphoma and one set of lung cancer microarray samples. Compared with the ordinary Euclidean distance metric, this distance measure produced more instructive, biologically relevant, visualizations when applying multidimensional scaling. This suggests the Isomap algorithm as a promising tool for the interpretation of microarray data. Furthermore, the results demonstrate the benefit and importance of taking nonlinearities in gene expression data into account.

Distances to Nearby Galaxies via Long Period Variables

NASA Astrophysics Data System (ADS)

Jurcevic, John S.

A new method of measuring extra-Galactic distances has been developed based on the relationship between the luminosity of red supergiant variable (RSV) stars at optical wavelengths and the period of their luminosity variation. This period-luminosity (PL) relationship has been calibrated with RSVs from the Galactic Perseus OB1 association, the Large Magellanic Cloud, and M33 in the broadband optical R and I-bands, in a narrow part of the I-band at 8250 Å, and in the infrared K-band. By using these RSV PL relations, the distances to a sample of nearby galaxies (M101, NGC 2403, and NGC 2366) were determined. These galaxies were chosen because they had existing Cepheid based distances which allowed for a comparison between the two methods and provided a means of verifying the effectiveness of the RSV PL relation. The galaxies were also chosen to span a range of metallicity to allow an investigation of any effects due to metallicity differences. Photometry in the R-band was obtained over a period of three years for the galaxies with a coverage of 20, 17, and 13 epochs for M101, NGC 2403, and NGC 2366, respectively. By looking for red variable stars with periods in the range 100-1200 days the total number of RSVs discovered in the three galaxies was 123. Assuming a distance modulus for the Large Magellanic Cloud of 18.5 +/- 0.1 mag, single epoch I-band photometry of the RSVs was used to construct random phase PL relations resulting in distance moduli for M101, NGC 2403, and NGC 2366 of 29.40 +/- 0.16, 27.67 +/- 0.16, and 27.86 +/- 0.20 mag, respectively. Similarly, PL relations were also found using phase averaged R-band magnitudes which produced distance moduli of 29.09 +/- 0.16, 27.56 +/- 0.16, and 27.76 +/- 0.21 mag, respectively. These distances have been corrected for extinction by assuming values of E(B - V) = 0.10, 0.04, and 0.04 mag. The distances derived agree with those found via Cepheids which indicates that RSVs provide a very useful new method for measuring

Quantum-limited heat conduction over macroscopic distances

PubMed Central

Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko

2016-01-01

The emerging quantum technological apparatuses1, 2, such as the quantum computer3–6, call for extreme performance in thermal engineering7. Cold distant heat sinks are needed for the quantized electric degrees of freedom due to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance8–10. However, the short distance between the heat-exchanging bodies in the previous experiments11–14 hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics15–17 which provides a basis for the superconducting quantum computer18–21. Especially, our results facilitate remote cooling of nanoelectronic devices using far-away in-situ-tunable heat sinks22, 23. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics24, 25. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications26. PMID:27239219

Time-Distance Helioseismology: Noise Estimation

NASA Astrophysics Data System (ADS)

Gizon, L.; Birch, A. C.

2004-10-01

As in global helioseismology, the dominant source of noise in time-distance helioseismology measurements is realization noise due to the stochastic nature of the excitation mechanism of solar oscillations. Characterizing noise is important for the interpretation and inversion of time-distance measurements. In this paper we introduce a robust definition of travel time that can be applied to very noisy data. We then derive a simple model for the full covariance matrix of the travel-time measurements. This model depends only on the expectation value of the filtered power spectrum and assumes that solar oscillations are stationary and homogeneous on the solar surface. The validity of the model is confirmed through comparison with SOHO MDI measurements in a quiet-Sun region. We show that the correlation length of the noise in the travel times is about half the dominant wavelength of the filtered power spectrum. We also show that the signal-to-noise ratio in quiet-Sun travel-time maps increases roughly as the square root of the observation time and is at maximum for a distance near half the length scale of supergranulation.

Being "at" University: The Social Topologies of Distance Students

ERIC Educational Resources Information Center

Bayne, Sian; Gallagher, Michael Sean; Lamb, James

2014-01-01

This paper considers how online, distance students enact the space of "the university", in the context of the rise of distance education within a traditional, "elite" institution. Aiming to provide insight into how students translate into distance the space of a university which has traditionally had its basis in conventional…

Distance Education: Why Are the Attrition Rates so High?

ERIC Educational Resources Information Center

Moody, Johnette

2004-01-01

Distance education is being hailed as the next best thing to sliced bread. But is it really? Many problems exist with distance-delivered courses. Everything from course development and management to the student not being adequately prepared are problematic and result in high attrition rates in distance-delivered courses. Students initially…

Factors that motivate and deter rehabilitation educators from participating in distance education.

PubMed

Edwards, Yolanda V

2004-01-01

The major purpose of the study was to conduct exploratory research on the motivational levels of rehabilitation educators whose programs have Comprehensive Service Personnel Development (CSPD; Department of Education grant) grants targeted toward distance education. Additionally, the study attempted to identify whether significant factors existed that would inhibit faculty participation in distance education. There were three research questions to examine: (a) Do distance educators and non-distance educators differ significantly in intrinsic motivational factors? (b) Do distance educators and non-distance educators differ significantly in extrinsic motivational factors? and (c) Do distance educators and non-distance educators differ significantly in inhibiting factors? The results showed that rehabilitation faculty with CSPD grants who are distance educators are more extrinsically motivated (such as increase in salary, monetary support for participation, job security, working conditions, technical support, and requirement by department) than non-distance educators. There were no significant differences in levels between distance educators and non-distance educators that are intrinsically motivated (scholarly pursuit, personal research tool, and job satisfaction). There was no significant difference between distance educators and non-distance educators in inhibiting factors.

An Overview of Distance Education at Boise State University. Research Report.

ERIC Educational Resources Information Center

Belcheir, Marcia J.; Atkinson, Janet

This study, first in a three-part series, looked at distance education at Boise State University, Idaho, to explore the current distance education delivery methods, the growth in distance education, enrollment, and teaching in distance education. Data from various university sources show that in the past 5 years, the numbers of distance education…

Increasing Access and Relevance in Distance Education

ERIC Educational Resources Information Center

Mendenhall, Robert W.

2009-01-01

Access to higher education is subject to many factors including affordability, time and geography. Distance education can deliver education to those that live far from a campus. Some of that distance education may be synchronous, or live, requiring students to be available at certain times. Flexibility and access are increased when the instruction…

Research into Distance Education = Fernlehre und Fernlehrforschung.

ERIC Educational Resources Information Center

Holmberg, Borje, Ed.; Ortner, Gerhard E., Ed.

The papers (from a symposium held at the Fern Universitat) included in this collection focus on distance education in theory and practice. Contributions are written in English or in German, with summaries available for each in the language not used for the paper concerned. Contributions are: (1) "Distance Education as Communication: The…

36 CFR 13.920 - Wildlife distance conditions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Wildlife distance conditions... Provisions § 13.920 Wildlife distance conditions. (a) Bears. The following are prohibited: (1) Approaching within 300 yards of a bear; or (2) Engaging in photography within 300 yards of a bear. (b) Other wildlife...

36 CFR 13.920 - Wildlife distance conditions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Wildlife distance conditions... Provisions § 13.920 Wildlife distance conditions. (a) Bears. The following are prohibited: (1) Approaching within 300 yards of a bear; or (2) Engaging in photography within 300 yards of a bear. (b) Other wildlife...

36 CFR 13.920 - Wildlife distance conditions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Wildlife distance conditions... Provisions § 13.920 Wildlife distance conditions. (a) Bears. The following are prohibited: (1) Approaching within 300 yards of a bear; or (2) Engaging in photography within 300 yards of a bear. (b) Other wildlife...

36 CFR 13.920 - Wildlife distance conditions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Wildlife distance conditions... Provisions § 13.920 Wildlife distance conditions. (a) Bears. The following are prohibited: (1) Approaching within 300 yards of a bear; or (2) Engaging in photography within 300 yards of a bear. (b) Other wildlife...

36 CFR 13.920 - Wildlife distance conditions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Wildlife distance conditions... Provisions § 13.920 Wildlife distance conditions. (a) Bears. The following are prohibited: (1) Approaching within 300 yards of a bear; or (2) Engaging in photography within 300 yards of a bear. (b) Other wildlife...

Perspectives on Group Work in Distance Learning

ERIC Educational Resources Information Center

Hausstatter, Rune Sarromaa; Nordkvelle, Yngve Troye

2007-01-01

Current distance education benefits greatly from educational software that makes group work possible for students who are separated in time and space. However, some students prefer distance education because they can work on their own. This paper explores how students react to expectations on behalf of the course provider to do their assignments…

Effects of Distance Learning on Learning Effectiveness

ERIC Educational Resources Information Center

Liu, Hong-Cheng; Yen, Jih-Rong

2014-01-01

The development of computers in the past two decades has resulted in the changes of education in enterprises and schools. The advance of computer hardware and platforms allow colleges generally applying distance courses to instruction that both Ministry of Education and colleges have paid attention to the development of Distance Learning. To…

Segmenting Michigan tourists based on distance traveled

Treesearch

Xiamei Xu; Tsao-Fang Yuan; Edwin Gomez; Joseph D. Fridgen

1998-01-01

The purpose of this study was to segment Michigan travelers into short, medium and long distance traveler groups by distance that they traveled from home to a primary destination in Michigan, and to compare travel behavior, trip characteristics and sociodemographics among these segments. Significant differences were identified in past trip experiences in Michigan,...

Properties of star clusters - I. Automatic distance and extinction estimates

NASA Astrophysics Data System (ADS)

Buckner, Anne S. M.; Froebrich, Dirk

2013-12-01

Determining star cluster distances is essential to analyse their properties and distribution in the Galaxy. In particular, it is desirable to have a reliable, purely photometric distance estimation method for large samples of newly discovered cluster candidates e.g. from the Two Micron All Sky Survey, the UK Infrared Deep Sky Survey Galactic Plane Survey and VVV. Here, we establish an automatic method to estimate distances and reddening from near-infrared photometry alone, without the use of isochrone fitting. We employ a decontamination procedure of JHK photometry to determine the density of stars foreground to clusters and a galactic model to estimate distances. We then calibrate the method using clusters with known properties. This allows us to establish distance estimates with better than 40 per cent accuracy. We apply our method to determine the extinction and distance values to 378 known open clusters and 397 cluster candidates from the list of Froebrich, Scholz & Raftery. We find that the sample is biased towards clusters of a distance of approximately 3 kpc, with typical distances between 2 and 6 kpc. Using the cluster distances and extinction values, we investigate how the average extinction per kiloparsec distance changes as a function of the Galactic longitude. We find a systematic dependence that can be approximated by AH(l) [mag kpc-1] = 0.10 + 0.001 × |l - 180°|/° for regions more than 60° from the Galactic Centre.

Measuring Distance of Fuzzy Numbers by Trapezoidal Fuzzy Numbers

NASA Astrophysics Data System (ADS)

Hajjari, Tayebeh

2010-11-01

Fuzzy numbers and more generally linguistic values are approximate assessments, given by experts and accepted by decision-makers when obtaining value that is more accurate is impossible or unnecessary. Distance between two fuzzy numbers plays an important role in linguistic decision-making. It is reasonable to define a fuzzy distance between fuzzy objects. To achieve this aim, the researcher presents a new distance measure for fuzzy numbers by means of improved centroid distance method. The metric properties are also studied. The advantage is the calculation of the proposed method is far simple than previous approaches.

A Unimodal Model for Double Observer Distance Sampling Surveys.

PubMed

Becker, Earl F; Christ, Aaron M

2015-01-01

Distance sampling is a widely used method to estimate animal population size. Most distance sampling models utilize a monotonically decreasing detection function such as a half-normal. Recent advances in distance sampling modeling allow for the incorporation of covariates into the distance model, and the elimination of the assumption of perfect detection at some fixed distance (usually the transect line) with the use of double-observer models. The assumption of full observer independence in the double-observer model is problematic, but can be addressed by using the point independence assumption which assumes there is one distance, the apex of the detection function, where the 2 observers are assumed independent. Aerially collected distance sampling data can have a unimodal shape and have been successfully modeled with a gamma detection function. Covariates in gamma detection models cause the apex of detection to shift depending upon covariate levels, making this model incompatible with the point independence assumption when using double-observer data. This paper reports a unimodal detection model based on a two-piece normal distribution that allows covariates, has only one apex, and is consistent with the point independence assumption when double-observer data are utilized. An aerial line-transect survey of black bears in Alaska illustrate how this method can be applied.

Complex networks in the Euclidean space of communicability distances

NASA Astrophysics Data System (ADS)

Estrada, Ernesto

2012-06-01

We study the properties of complex networks embedded in a Euclidean space of communicability distances. The communicability distance between two nodes is defined as the difference between the weighted sum of walks self-returning to the nodes and the weighted sum of walks going from one node to the other. We give some indications that the communicability distance identifies the least crowded routes in networks where simultaneous submission of packages is taking place. We define an index Q based on communicability and shortest path distances, which allows reinterpreting the “small-world” phenomenon as the region of minimum Q in the Watts-Strogatz model. It also allows the classification and analysis of networks with different efficiency of spatial uses. Consequently, the communicability distance displays unique features for the analysis of complex networks in different scenarios.

Matrimonial distance, inbreeding coefficient and population size: Dhangar data.

PubMed

Majumder, P P; Malhotra, K C

1979-01-01

Data on the distance between the birthplaces of spouses (matrimonial distance) were collected from 2,260 married individuals belonging to 21 endogamous castes of the Dhangar (shepherd) cast-cluster of Maharashtra, India. The general form of the distribution of matrimonial distances is one which is extremely positively skewed and leptokurtic. The percentage of intra-village marriages generally decreases from the southern areas of Maharashtra to the northern areas of the state, as does the inbreeding coefficient. This situation is in conformity with the socio-cultural norms regulating matrimonial choice in south and north India. An attempt has been made to relate the degree of inbreeding to the mean matrimonial distance and population size. The mean matrimonial distance is more useful in predicting the degree of inbreeding than population size.

Student Engagement in Distance-Based Vocational Education

ERIC Educational Resources Information Center

Yates, Anne; Brindley-Richards, Wendy; Thistoll, Tony

2014-01-01

Students enrolled in distance education courses tend to have lower course completion rates than those who attend face-to-face classes (Simpson, 2013). This article reports on a collective case study undertaken at a vocational, distance education provider in New Zealand, whose course completion rates have risen over recent years to match those of…

Challenges Encountered by a Distance Learning Organisation

ERIC Educational Resources Information Center

Malik, Sangeeta

2012-01-01

Distance learning as the name indicates is a learning, learner gets from distant places. In this learning system, learner and educators are separated by space & time. Lots of distance learning organizations are spreading to meet the increased demand of current & future needs of adult education. The rapid spread of these organizations doesn't mean…

Digital Competence Model of Distance Learning Students

ERIC Educational Resources Information Center

da Silva, Ketia Kellen A.; Behar, Patricia A.

2017-01-01

This article presents the development of a digital competency model of Distance Learning (DL) students in Brazil called CompDigAl_EAD. The following topics were addressed in this study: Educational Competences, Digital Competences, and Distance Learning students. The model was developed between 2015 and 2016 and is being validated in 2017. It was…

Distance estimation of some selected small Bok globules

NASA Astrophysics Data System (ADS)

Das, A.; Das, H. S.; Senorita Devi, A.

2015-09-01

The distance determination of a small Bok globule is often difficult because of its small size and opaqueness. In this work, we determine the distances to six small Bok globules (CB 17, CB 24, CB 188, CB 224, CB 230 and CB 240) using near-infrared photometry (2MASS JHKS colours). The distances to these clouds are estimated to be 478 ± 88, 293 ± 54, 262 ± 49, 378 ± 70, 293 ± 54 and 429 ± 79 pc, respectively.

Distance education: The Introduction to College Chemistry course

NASA Astrophysics Data System (ADS)

Rice, Lisa A.

The purpose of this study was to compare a group of students in a traditional introductory college chemistry course to their distance learning counterparts. Both of the groups were required to have videotaped lessons and workbooks, but the traditional group met for two and one half hours each week with the instructor, whereas the distance students were not obligated to attend classroom meetings. The same instructor taught both of the groups and both were given equal access opportunities to the instructor beyond class meetings. The literature review included in this study indicated that distance learning has changed from a less popular alternative method for study to the forefront in modern academic institutions. The two target populations for this study were students enrolled in the Edison Community College Introduction to College Chemistry videotaped course and students taking the same course in a traditional setting. The study was conducted over a two consecutive semester interval, from August 2002 through May 2003. These two groups were compared on a number of items including gender, student attitudes about their own learning style, ethnicity, and final course grade. Information regarding attrition and reasons for choosing to take the course was collected. The results of this study found a significant difference in the number of students who withdrew from each course, with the distance students having the greater attrition rate. Gender and ethnicity were not significant in terms of student success when comparing the two groups. The self-reported behavior types showed no significant correlation to success for either the traditional or the distance students. However, many of the distance students felt that meeting occasionally for a face-to-face laboratory course would have been beneficial. Suggested applications of this study include strategies for a more successful distance learning experience for students. Also, laboratory courses such as chemistry have some

Use of Distance Education in Dental Hygiene Programs.

ERIC Educational Resources Information Center

Grimes, Ellen B.

2002-01-01

Surveyed dental hygiene programs to determine the prevalence of distance education use. Found that 22 percent have distance education, and that most were satisfied with it as an adequate alternative to traditional approaches. (EV)

Unified treatment of the luminosity distance in cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Jaiyul; Scaccabarozzi, Fulvio, E-mail: jyoo@physik.uzh.ch, E-mail: fulvio@physik.uzh.ch

Comparing the luminosity distance measurements to its theoretical predictions is one of the cornerstones in establishing the modern cosmology. However, as shown in Biern and Yoo, its theoretical predictions in literature are often plagued with infrared divergences and gauge-dependences. This trend calls into question the sanity of the methods used to derive the luminosity distance. Here we critically investigate four different methods—the geometric approach, the Sachs approach, the Jacobi mapping approach, and the geodesic light cone (GLC) approach to modeling the luminosity distance, and we present a unified treatment of such methods, facilitating the comparison among the methods and checkingmore » their sanity. All of these four methods, if exercised properly, can be used to reproduce the correct description of the luminosity distance.« less

Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight.

PubMed

Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

2016-01-01

We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5-6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance.

Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight

PubMed Central

Clément, Gilles; Loureiro, Nuno; Sousa, Duarte; Zandvliet, Andre

2016-01-01

We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5–6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance. PMID:27463106

Confronting Cost and Pricing Issues in Distance Education.

ERIC Educational Resources Information Center

Taylor, Thomas H.; Parker, G. D., III; Tebeaux, Elizabeth

2001-01-01

Asserts that "the devil is in the details" when determining costs and prices for distance delivery of courses, and describes Texas A&M University's process of determining cost and price for distance education courses. (EV)

The Gould’s Belt Distances Survey (GOBELINS). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

NASA Astrophysics Data System (ADS)

Ortiz-León, Gisela N.; Loinard, Laurent; Kounkel, Marina A.; Dzib, Sergio A.; Mioduszewski, Amy J.; Rodríguez, Luis F.; Torres, Rosa M.; González-Lópezlira, Rosa A.; Pech, Gerardo; Rivera, Juana L.; Hartmann, Lee; Boden, Andrew F.; Evans, Neal J., II; Briceño, Cesar; Tobin, John J.; Galli, Phillip A. B.; Gudehus, Donald

2017-01-01

We present the first results of the Gould’s Belt Distances Survey (GOBELINS), a project aimed at measuring the proper motion and trigonometric parallax of a large sample of young stars in nearby regions using multi-epoch Very Long Baseline Array (VLBA) radio observations. Enough VLBA detections have now been obtained for 16 stellar systems in Ophiuchus to derive their parallax and proper motion. This leads to distance determinations for individual stars with an accuracy of 0.3 to a few percent. In addition, the orbits of six multiple systems were modelled by combining absolute positions with VLBA (and, in some cases, near-infrared) angular separations. Twelve stellar systems are located in the dark cloud Lynds 1688 the individual distances for this sample are highly consistent with one another and yield a mean parallax for Lynds 1688 of \\varpi =7.28+/- 0.06 mas, corresponding to a distance d=137.3+/- 1.2 pc. This represents an accuracy greater than 1%. Three systems for which astrometric elements could be measured are located in the eastern streamer (Lynds 1689) and yield an estimate of \\varpi =6.79+/- 0.16 mas, corresponding to a distance d=147.3+/- 3.4 pc. This suggests that the eastern streamer is located about 10 pc farther than the core, but this conclusion needs to be confirmed by observations of additional sources in the eastern streamer (currently being collected). From the measured proper motions, we estimate the one-dimensional velocity dispersion in Lynds 1688 to be 2.8 ± 1.8 and 3.0 ± 2.0 km s-1, in R.A. and decl., respectively; these are larger than, but still consistent within 1σ of, those found in other studies.

The Effect of Debris-Flow Composition on Runout Distance

NASA Astrophysics Data System (ADS)

Haas, T. D.; Braat, L.; Leuven, J.; Lokhorst, I.; Kleinhans, M. G.

2014-12-01

Estimating runout distance is of major importance for the assessment and mitigation of debris-flow hazards. Debris-flow runout distance depends on debris-flow composition and topography, but state-of-the-art runout prediction methods are mainly based on topographical parameters and debris-flow volume, while composition is generally neglected or incorporated in empirical constants. Here we experimentally investigated the effect of debris-flow composition and topography on runout distance. We created the first small-scale experimental debris flows with self-formed levees, distinct lobes and morphology and texture accurately resembling natural debris flows. In general, debris-flow composition had a larger effect on runout distance than topography. Enhancing channel slope and width, outflow plain slope, debris-flow size and water fraction leads to an increase in runout distance. However, runout distance shows an optimum relation with coarse-material and clay fraction. An increase in coarse-material fraction leads to larger runout distances by increased grain collisional forces and more effective levee formation, but too much coarse debris causes a large accumulation of coarse debris at the flow front, enhancing friction and decreasing runout. An increase in clay fraction initially enlarges the volume and viscosity of the interstitial fluid, liquefying the flow and enhancing runout, while a further increase leads to very viscous flows with high yield strength, reducing runout. These results highlight the importance and further need of research on the relation between debris-flow composition and runout distance. Our experiments further provide valuable insight on the effects of debris-flow composition on depositional mechanisms and deposit morphology.

The effect of debris-flow composition on runout distance

NASA Astrophysics Data System (ADS)

de Haas, Tjalling; Braat, Lisanne; Leuven, Jasper; Lokhorst, Ivar; Kleinhans, Maarten

2015-04-01

Estimating runout distance is of major importance for the assessment and mitigation of debris-flow hazards. Debris-flow runout distance depends on debris-flow composition and topography, but state-of-the-art runout prediction methods are mainly based on topographical parameters and debris-flow volume, while composition is generally neglected or incorporated in empirical constants. Here we experimentally investigated the effect of debris-flow composition and topography on runout distance. We created the first small-scale experimental debris flows with self-formed levees, distinct lobes and morphology and texture accurately resembling natural debris flows. In general, the effect of debris-flow composition on runout distance was larger than the effect of topography. Enhancing channel slope and width, outflow plain slope, debris-flow size and water fraction leads to an increase in runout distance. However, runout distance shows an optimum relation with coarse-material and clay fraction. An increase in coarse-material fraction leads to larger runout distances by increased grain collisional forces and more effective levee formation, but too much coarse debris causes a large accumulation of coarse debris at the flow front, enhancing friction and decreasing runout. An increase in clay fraction initially enlarges the volume and viscosity of the interstitial fluid, liquefying the flow and enhancing runout, while a further increase leads to very viscous flows with high yield strength, reducing runout. These results highlight the importance and further need of research on the relation between debris-flow composition and runout distance. Our experiments further provide valuable insight on the effects of debris-flow composition on depositional mechanisms and deposit morphology.

Perspectives on Distance Education and Social Media

ERIC Educational Resources Information Center

Powers, Lisa; Alhussain, Ruqaya; Averbeck, Clemens; Warner, Andre

2012-01-01

There is a dramatic shift in the tools that are used in today's technology-based distance education. While distance education is not new, there are new types of socially rich, mobile technologies that empower learners to be more in control of what they learn, when they learn it, and how they learn it. Students are taking more responsibility for…

Adding Interactivity to Web Based Distance Learning.

ERIC Educational Resources Information Center

Cafolla, Ralph; Knee, Richard

Web Based Distance Learning (WBDL) is a form of distance learning based on providing instruction mainly on the World Wide Web. This paradigm has limitations, especially the lack of interactivity inherent in the Web. The purpose of this paper is to discuss some of the technologies the authors have used in their courses at Florida Atlantic…

A History of Distance Education in Mexico

ERIC Educational Resources Information Center

Castaneda, Manuel Moreno

2005-01-01

Research on distance education in Mexico is still in the embryonic stage, in spite of its long history. One indication is that among the lines of research defined by the Mexican Council on Educational Research, the leading organization in the field in Mexico, distance education does not even appear. Only recently, in the last few years, has an…

Distance Learning Students' Need: Evaluating Interactions from Moore's Theory of Transactional Distance

ERIC Educational Resources Information Center

Ustati, Rusmanizah; Hassan, Sharifah Sariah Syed

2013-01-01

This study draws on the experience from a focus group interviews under the distance learning programme known as "Program Pensiswazahan Guru" (PPG) organized by the Malaysian Ministry of Education in collaboration with local universities and institutes of education. Its purpose is to uncover students' perception about the platform used by…

Where does distance matter? Distance to the closest maternity unit and risk of foetal and neonatal mortality in France.

PubMed

Pilkington, Hugo; Blondel, Béatrice; Drewniak, Nicolas; Zeitlin, Jennifer

2014-12-01

The number of maternity units has declined in France, raising concerns about the possible impact of increasing travel distances on perinatal health outcomes. We investigated impact of distance to closest maternity unit on perinatal mortality. Data from the French National Vital Statistics Registry were used to construct foetal and neonatal mortality rates over 2001-08 by distance from mother's municipality of residence and the closest municipality with a maternity unit. Data from French neonatal mortality certificates were used to compute neonatal death rates after out-of-hospital birth. Relative risks by distance were estimated, adjusting for individual and municipal-level characteristics. Seven percent of births occurred to women residing at ≥30 km from a maternity unit and 1% at ≥45 km. Foetal and neonatal mortality rates were highest for women living at <5 km from a maternity unit. For foetal mortality, rates increased at ≥45 km compared with 5-45 km. In adjusted models, long distance to a maternity unit had no impact on overall mortality but women living closer to a maternity unit had a higher risk of neonatal mortality. Neonatal deaths associated with out-of-hospital birth were rare but more frequent at longer distances. At the municipal-level, higher percentages of unemployment and foreign-born residents were associated with increased mortality. Overall mortality was not associated with living far from a maternity unit. Mortality was elevated in municipalities with social risk factors and located closest to a maternity unit, reflecting the location of maternity units in deprived areas with risk factors for poor outcome. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association.

Comparative evaluation of ultrasound scanner accuracy in distance measurement

NASA Astrophysics Data System (ADS)

Branca, F. P.; Sciuto, S. A.; Scorza, A.

2012-10-01

The aim of the present study is to develop and compare two different automatic methods for accuracy evaluation in ultrasound phantom measurements on B-mode images: both of them give as a result the relative error e between measured distances, performed by 14 brand new ultrasound medical scanners, and nominal distances, among nylon wires embedded in a reference test object. The first method is based on a least squares estimation, while the second one applies the mean value of the same distance evaluated at different locations in ultrasound image (same distance method). Results for both of them are proposed and explained.

Detecting duplicate biological entities using Shortest Path Edit Distance.

PubMed

Rudniy, Alex; Song, Min; Geller, James

2010-01-01

Duplicate entity detection in biological data is an important research task. In this paper, we propose a novel and context-sensitive Shortest Path Edit Distance (SPED) extending and supplementing our previous work on Markov Random Field-based Edit Distance (MRFED). SPED transforms the edit distance computational problem to the calculation of the shortest path among two selected vertices of a graph. We produce several modifications of SPED by applying Levenshtein, arithmetic mean, histogram difference and TFIDF techniques to solve subtasks. We compare SPED performance to other well-known distance algorithms for biological entity matching. The experimental results show that SPED produces competitive outcomes.

Dependency distances in natural mixed languages. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

NASA Astrophysics Data System (ADS)

Wang, Lin

2017-07-01

Haitao Liu et al.'s article [1] offers a comprehensive account of the diversity of syntactic patterns in human languages in terms of an important index of memory burden and syntactic difficulty - the dependency distance. Natural languages, a complex system, present overall shorter dependency distances under the universal pressure for dependency distance minimization; however, there exist some relatively-long-distance dependencies, which reflect that language can constantly adapt itself to some deep-level biological or functional constraints.

Quantile regression applied to spectral distance decay

USGS Publications Warehouse

Rocchini, D.; Cade, B.S.

2008-01-01

Remotely sensed imagery has long been recognized as a powerful support for characterizing and estimating biodiversity. Spectral distance among sites has proven to be a powerful approach for detecting species composition variability. Regression analysis of species similarity versus spectral distance allows us to quantitatively estimate the amount of turnover in species composition with respect to spectral and ecological variability. In classical regression analysis, the residual sum of squares is minimized for the mean of the dependent variable distribution. However, many ecological data sets are characterized by a high number of zeroes that add noise to the regression model. Quantile regressions can be used to evaluate trend in the upper quantiles rather than a mean trend across the whole distribution of the dependent variable. In this letter, we used ordinary least squares (OLS) and quantile regressions to estimate the decay of species similarity versus spectral distance. The achieved decay rates were statistically nonzero (p < 0.01), considering both OLS and quantile regressions. Nonetheless, the OLS regression estimate of the mean decay rate was only half the decay rate indicated by the upper quantiles. Moreover, the intercept value, representing the similarity reached when the spectral distance approaches zero, was very low compared with the intercepts of the upper quantiles, which detected high species similarity when habitats are more similar. In this letter, we demonstrated the power of using quantile regressions applied to spectral distance decay to reveal species diversity patterns otherwise lost or underestimated by OLS regression. ?? 2008 IEEE.

Exact geodesic distances in FLRW spacetimes

NASA Astrophysics Data System (ADS)

Cunningham, William J.; Rideout, David; Halverson, James; Krioukov, Dmitri

2017-11-01

Geodesics are used in a wide array of applications in cosmology and astrophysics. However, it is not a trivial task to efficiently calculate exact geodesic distances in an arbitrary spacetime. We show that in spatially flat (3 +1 )-dimensional Friedmann-Lemaître-Robertson-Walker (FLRW) spacetimes, it is possible to integrate the second-order geodesic differential equations, and derive a general method for finding both timelike and spacelike distances given initial-value or boundary-value constraints. In flat spacetimes with either dark energy or matter, whether dust, radiation, or a stiff fluid, we find an exact closed-form solution for geodesic distances. In spacetimes with a mixture of dark energy and matter, including spacetimes used to model our physical universe, there exists no closed-form solution, but we provide a fast numerical method to compute geodesics. A general method is also described for determining the geodesic connectedness of an FLRW manifold, provided only its scale factor.

Advanced hierarchical distance sampling

USGS Publications Warehouse

Royle, Andy

2016-01-01

In this chapter, we cover a number of important extensions of the basic hierarchical distance-sampling (HDS) framework from Chapter 8. First, we discuss the inclusion of “individual covariates,” such as group size, in the HDS model. This is important in many surveys where animals form natural groups that are the primary observation unit, with the size of the group expected to have some influence on detectability. We also discuss HDS integrated with time-removal and double-observer or capture-recapture sampling. These “combined protocols” can be formulated as HDS models with individual covariates, and thus they have a commonality with HDS models involving group structure (group size being just another individual covariate). We cover several varieties of open-population HDS models that accommodate population dynamics. On one end of the spectrum, we cover models that allow replicate distance sampling surveys within a year, which estimate abundance relative to availability and temporary emigration through time. We consider a robust design version of that model. We then consider models with explicit dynamics based on the Dail and Madsen (2011) model and the work of Sollmann et al. (2015). The final major theme of this chapter is relatively newly developed spatial distance sampling models that accommodate explicit models describing the spatial distribution of individuals known as Point Process models. We provide novel formulations of spatial DS and HDS models in this chapter, including implementations of those models in the unmarked package using a hack of the pcount function for N-mixture models.

Interactive Distance Education: Improvisation Helps Bridge the Gap.

ERIC Educational Resources Information Center

Yucha, Carolyn B.

1996-01-01

Describes distance learning through the use of interactive duplex video and audio. Improvisation techniques force active participation by students. Addresses faculty concerns about the interrelationships between instructor and students and among students in distance education environments. (MKR)

[A Study of the Relationship Among Genetic Distances, NIR Spectra Distances, and NIR-Based Identification Model Performance of the Seeds of Maize Iinbred Lines].

PubMed

Liu, Xu; Jia, Shi-qiang; Wang, Chun-ying; Liu, Zhe; Gu, Jian-cheng; Zhai, Wei; Li, Shao-ming; Zhang, Xiao-dong; Zhu, De-hai; Huang, Hua-jun; An, Dong

2015-09-01

This paper explored the relationship among genetic distances, NIR spectra distances and NIR-based identification model performance of the seeds of maize inbred lines. Using 3 groups (total 15 pairs) of maize inbred lines whose genetic distaches are different as experimental materials, we calculates the genetic distance between these seeds with SSR markers and uses Euclidean distance between distributed center points of maize NIR spectrum in the PCA space as the distances of NIR spectrum. BPR method is used to build identification model of inbred lines and the identification accuracy is used as a measure of model identification performance. The results showed that, the correlation of genetic distance and spectra distancesis 0.9868, and it has a correlation of 0.9110 with the identification accuracy, which is highly correlated. This means near-Infrared spectrum of seedscan reflect genetic relationship of maize inbred lines. The smaller the genetic distance, the smaller the distance of spectrum, the poorer ability of model to identify. In practical application, near infrared spectrum analysis technology has the potential to be used to analyze maize inbred genetic relations, contributing much to genetic breeding, identification of species, purity sorting and so on. What's more, when creating a NIR-based identification model, the impact of the maize inbred lines which have closer genetic relationship should be fully considered.

Going the Distance: Delivery of High School Drug Prevention via Distance Education

ERIC Educational Resources Information Center

Wyrick, David L.; Fearnow-Kenney, Melodie; Wyrick, Cheryl Haworth; Orsini, Muhsin Michael; Strack, Robert W.; Milroy, Jeffrey J.

2010-01-01

The purpose of this project was to develop a technology that can be used in schools where there are insufficient resources to implement a quality drug prevention program. The specific technology--distance education via teleconferencing--allows a highly qualified teacher to deliver programs in such settings with increased quality. A promising high…

Supporting Students in Open and Distance Learning. Open and Distance Learning Series.

ERIC Educational Resources Information Center

Simpson, Ormond

This book, which is intended for individuals involved in recruiting and teaching students in open and distance learning (ODL) situations, examines academic and nonacademic student support issues in ODL. The following are among the topics discussed in the book's 14 chapters: (1) models and definitions of ODL systems; (2) rationale for student…

Aging and the visual perception of exocentric distance.

PubMed

Norman, J Farley; Adkins, Olivia C; Norman, Hideko F; Cox, Andrea G; Rogers, Connor E

2015-04-01

The ability of 18 younger and older adults to visually perceive exocentric distances was evaluated. The observers judged the extent of fronto-parallel and in-depth spatial intervals at a variety of viewing distances from 50cm to 164.3cm. Most of the observers perceived in-depth intervals to be significantly smaller than fronto-parallel intervals, a finding that is consistent with previous studies. While none of the individual observers' judgments of exocentric distance were accurate, the judgments of the older observers were significantly more accurate than those of the younger observers. The precision of the observers' judgments across repeated trials, however, was not affected by age. The results demonstrate that increases in age can produce significant improvements in the visual ability to perceive the magnitude of exocentric distances. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distance Learning 2001: Proceedings of the Annual Conference on Distance Teaching & Learning (17th, Madison, Wisconsin, August 8-10, 2001).

ERIC Educational Resources Information Center

Wisconsin Univ. System, Madison.

This document contains 82 papers and 6 workshop presentations from a conference on distance teaching and learning. The following are among the papers included: "Examples and Tools for Building Web-Based Learning Experiences" (Steven A. Ackerman, Thomas Whittaker); "Online Testing in Distance Education" (Tricia Ahern);…

A Catalog of Distances to Molecular Clouds from Pan-STARRS1

NASA Astrophysics Data System (ADS)

Schlafly, Eddie; Green, G.; Finkbeiner, D. P.; Rix, H.

2014-01-01

We present a catalog of distances to molecular clouds, derived from PanSTARRS-1 photometry. We simultaneously infer the full probability distribution function of reddening and distance of the stars towards these clouds using the technique of Green et al. (2013) (see neighboring poster). We fit the resulting measurements using a simple dust screen model to infer the distance to each cloud. The result is a large, homogeneous catalog of distances to molecular clouds. For clouds with heliocentric distances greater than about 200 pc, typical statistical uncertainties in the distances are 5%, with systematic uncertainty stemming from the quality of our stellar models of about 10%. We have applied this analysis to many of the most well-studied clouds in the δ > -30° sky, including Orion, California, Taurus, Perseus, and Cepheus. We have also studied the entire catalog of Magnani, Blitz, and Mundy (1985; MBM), though for about half of those clouds we can provide only upper limits on the distances. We compare our distances with distances from the literature, when available, and find good agreement.

Laser fresnel distance measuring system and method

NASA Technical Reports Server (NTRS)

Campbell, Jonathan W. (Inventor); Lehner, David L. (Inventor); Smalley, Larry L. (Inventor); Smith, legal representative, Molly C. (Inventor); Sanders, Alvin J. (Inventor); Earl, Dennis Duncan (Inventor); Allison, Stephen W. (Inventor); Smith, Kelly L. (Inventor)

2008-01-01

A method and system for determining range to a target are provided. A beam of electromagnetic energy is transmitted through an aperture in an opaque screen such that a portion of the beam passes through the aperture to generate a region of diffraction that varies as a function of distance from the aperture. An imaging system is focused on a target plane in the region of diffraction with the generated image being compared to known diffraction patterns. Each known diffraction pattern has a unique value associated therewith that is indicative of a distance from the aperture. A match between the generated image and at least one of the known diffraction patterns is indicative of a distance between the aperture and target plane.

Improved Apparatus for Measuring Distance Between Axles

NASA Technical Reports Server (NTRS)

Willard, Douglas E.; Townsend, Ivan I., III

2003-01-01

An improved version of an optoelectronic apparatus for measuring distances of the order of tens of feet with an error no larger than a small fraction of an inch (a few millimeters) has been built. Like the previous version, the present improved version of the apparatus is designed to measure the distance approximately equal to 66 ft (approximately equal to 20 m) between the axes of rotation of the front and rear tires of the space shuttle orbiter as it rests in a ground-based processing facility. Like the previous version, the present version could also be adapted for similar purposes in other settings: Examples include measuring perpendicular distance from a wall in a building, placement of architectural foundations, and general alignment and measurement operations.

Multiresolution Distance Volumes for Progressive Surface Compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laney, D E; Bertram, M; Duchaineau, M A

2002-04-18

We present a surface compression method that stores surfaces as wavelet-compressed signed-distance volumes. Our approach enables the representation of surfaces with complex topology and arbitrary numbers of components within a single multiresolution data structure. This data structure elegantly handles topological modification at high compression rates. Our method does not require the costly and sometimes infeasible base mesh construction step required by subdivision surface approaches. We present several improvements over previous attempts at compressing signed-distance functions, including an 0(n) distance transform, a zero set initialization method for triangle meshes, and a specialized thresholding algorithm. We demonstrate the potential of sampled distancemore » volumes for surface compression and progressive reconstruction for complex high genus surfaces.« less

Novel approach for image skeleton and distance transformation parallel algorithms

NASA Astrophysics Data System (ADS)

Qing, Kent P.; Means, Robert W.

1994-05-01

Image Understanding is more important in medical imaging than ever, particularly where real-time automatic inspection, screening and classification systems are installed. Skeleton and distance transformations are among the common operations that extract useful information from binary images and aid in Image Understanding. The distance transformation describes the objects in an image by labeling every pixel in each object with the distance to its nearest boundary. The skeleton algorithm starts from the distance transformation and finds the set of pixels that have a locally maximum label. The distance algorithm has to scan the entire image several times depending on the object width. For each pixel, the algorithm must access the neighboring pixels and find the maximum distance from the nearest boundary. It is a computational and memory access intensive procedure. In this paper, we propose a novel parallel approach to the distance transform and skeleton algorithms using the latest VLSI high- speed convolutional chips such as HNC's ViP. The algorithm speed is dependent on the object's width and takes (k + [(k-1)/3]) * 7 milliseconds for a 512 X 512 image with k being the maximum distance of the largest object. All objects in the image will be skeletonized at the same time in parallel.

Dependency Distance Differences across Interpreting Types: Implications for Cognitive Demand

PubMed Central

Liang, Junying; Fang, Yuanyuan; Lv, Qianxi; Liu, Haitao

2017-01-01

Interpreting is generally recognized as a particularly demanding language processing task for the cognitive system. Dependency distance, the linear distance between two syntactically related words in a sentence, is an index of sentence complexity and is also able to reflect the cognitive constraints during various tasks. In the current research, we examine the difference in dependency distance among three interpreting types, namely, simultaneous interpreting, consecutive interpreting and read-out translated speech based on a treebank comprising these types of interpreting output texts with dependency annotation. Results show that different interpreting renditions yield different dependency distances, and consecutive interpreting texts entail the smallest dependency distance other than those of simultaneous interpreting and read-out translated speech, suggesting that consecutive interpreting bears heavier cognitive demands than simultaneous interpreting. The current research suggests for the first time that interpreting is an extremely demanding cognitive task that can further mediate the dependency distance of output sentences. Such findings may be due to the minimization of dependency distance under cognitive constraints. PMID:29312027

Viewing distance matter to perceived intensity of facial expressions

PubMed Central

Gerhardsson, Andreas; Högman, Lennart; Fischer, Håkan

2015-01-01

In our daily perception of facial expressions, we depend on an ability to generalize across the varied distances at which they may appear. This is important to how we interpret the quality and the intensity of the expression. Previous research has not investigated whether this so called perceptual constancy also applies to the experienced intensity of facial expressions. Using a psychophysical measure (Borg CR100 scale) the present study aimed to further investigate perceptual constancy of happy and angry facial expressions at varied sizes, which is a proxy for varying viewing distances. Seventy-one (42 females) participants rated the intensity and valence of facial expressions varying in distance and intensity. The results demonstrated that the perceived intensity (PI) of the emotional facial expression was dependent on the distance of the face and the person perceiving it. An interaction effect was noted, indicating that close-up faces are perceived as more intense than faces at a distance and that this effect is stronger the more intense the facial expression truly is. The present study raises considerations regarding constancy of the PI of happy and angry facial expressions at varied distances. PMID:26191035

Adaptive distance metric learning for diffusion tensor image segmentation.

PubMed

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C N; Chu, Winnie C W

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework.

Adaptive Distance Metric Learning for Diffusion Tensor Image Segmentation

PubMed Central

Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C. N.; Chu, Winnie C. W.

2014-01-01

High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework. PMID:24651858

Cultural interaction and biological distance in postclassic period Mexico.

PubMed

Ragsdale, Corey S; Edgar, Heather J H

2015-05-01

Economic, political, and cultural relationships connected virtually every population throughout Mexico during Postclassic period (AD 900-1520). Much of what is known about population interaction in prehistoric Mexico is based on archaeological or ethnohistoric data. What is unclear, especially for the Postclassic period, is how these data correlate with biological population structure. We address this by assessing biological (phenotypic) distances among 28 samples based upon a comparison of dental morphology trait frequencies, which serve as a proxy for genetic variation, from 810 individuals. These distances were compared with models representing geographic and cultural relationships among the same groups. Results of Mantel and partial Mantel matrix correlation tests show that shared migration and trade are correlated with biological distances, but geographic distance is not. Trade and political interaction are also correlated with biological distance when combined in a single matrix. These results indicate that trade and political relationships affected population structure among Postclassic Mexican populations. We suggest that trade likely played a major role in shaping patterns of interaction between populations. This study also shows that the biological distance data support the migration histories described in ethnohistoric sources. © 2015 Wiley Periodicals, Inc.

Forest cover influences dispersal distance of white-tailed deer

USGS Publications Warehouse

Long, E.S.; Diefenbach, D.R.; Rosenberry, C.S.; Wallingford, B.D.; Grund, M.D.

2005-01-01

Animal dispersal patterns influence gene flow, disease spread, population dynamics, spread of invasive species, and establishment of rare or endangered species. Although differences in dispersal distances among taxa have been reported, few studies have described plasticity of dispersal distance among populations of a single species. In 2002-2003, we radiomarked 308 juvenile (7- to 10-month-old), male white-tailed deer (Odocoileus virginianus) in 2 study areas in Pennsylvania. By using a meta-analysis approach, we compared dispersal rates and distances from these populations together with published reports of 10 other nonmigratory populations of white-tailed deer. Population density did not influence dispersal rate or dispersal distance, nor did forest cover influence dispersal rate. However, average (r2 = 0.94, P < 0.001, d.f. = 9) and maximum (r2 = 0.86, P = 0.001, d.f. = 7) dispersal distances of juvenile male deer were greater in habitats with less forest cover. Hence, dispersal behavior of this habitat generalist varies, and use of landscape data to predict population-specific dispersal distances may aid efforts to model population spread, gene flow, or disease transmission. ?? 2005 American Society of Mammalogists.

Distance matrix-based approach to protein structure prediction.

PubMed

Kloczkowski, Andrzej; Jernigan, Robert L; Wu, Zhijun; Song, Guang; Yang, Lei; Kolinski, Andrzej; Pokarowski, Piotr

2009-03-01

Much structural information is encoded in the internal distances; a distance matrix-based approach can be used to predict protein structure and dynamics, and for structural refinement. Our approach is based on the square distance matrix D = [r(ij)(2)] containing all square distances between residues in proteins. This distance matrix contains more information than the contact matrix C, that has elements of either 0 or 1 depending on whether the distance r (ij) is greater or less than a cutoff value r (cutoff). We have performed spectral decomposition of the distance matrices D = sigma lambda(k)V(k)V(kT), in terms of eigenvalues lambda kappa and the corresponding eigenvectors v kappa and found that it contains at most five nonzero terms. A dominant eigenvector is proportional to r (2)--the square distance of points from the center of mass, with the next three being the principal components of the system of points. By predicting r (2) from the sequence we can approximate a distance matrix of a protein with an expected RMSD value of about 7.3 A, and by combining it with the prediction of the first principal component we can improve this approximation to 4.0 A. We can also explain the role of hydrophobic interactions for the protein structure, because r is highly correlated with the hydrophobic profile of the sequence. Moreover, r is highly correlated with several sequence profiles which are useful in protein structure prediction, such as contact number, the residue-wise contact order (RWCO) or mean square fluctuations (i.e. crystallographic temperature factors). We have also shown that the next three components are related to spatial directionality of the secondary structure elements, and they may be also predicted from the sequence, improving overall structure prediction. We have also shown that the large number of available HIV-1 protease structures provides a remarkable sampling of conformations, which can be viewed as direct structural information about the

Effects of target distance on select biomechanical parameters in taekwondo roundhouse kick.

PubMed

Falco, Coral; Molina-García, Javier; Alvarez, Octavio; Estevan, Isaac

2013-11-01

The aim of this study was to investigate the effects of target distance on temporal and impact force parameters that are important performance factors in taekwondo kicks. Forty-nine taekwondo athletes (age = 24.5 +/- 5.9 years; mass = 79.9 +/- 10.8 kg) were recruited: 13 male experts, 21 male novices, 8 female experts, and 6 female novices. Impact force, reaction time, and execution time were computed. Three-way repeated measure ANOVAs revealed significant 'distance' effect on impact force, reaction time, and execution time (p = 0.001). Comparisons between distance conditions revealed that taekwondo athletes kicked with higher impact force from short distance (17.6 +/- 7.5 N/kg) than from long distance (13.1 +/- 5.7 N/kg) (p < 0.001), had lower reaction time from short distance (498 +/- 90 ms) and normal distance (521 +/- 111 ms) than from long distance (602 +/- 121 ms) (p < 0.001), and had lower execution time from short distance (261 +/- 69 ms/m) than from normal distance (306 +/- 105 ms/m) or from long distance (350 +/- 106 ms/m) (p = 0.003 and p < 0.001, respectively). In conclusion, target distance affected the kick performance; as distance increases, impact force decreased and reaction time increased. Therefore, when reaction to a simple visual stimulus is needed, kicking from a long distance is not recommended, as longer time is required to respond.

A distance estimate to the Cygnus Loop based on the distances to two stars located within the remnant

NASA Astrophysics Data System (ADS)

Fesen, Robert A.; Neustadt, Jack M. M.; Black, Christine S.; Milisavljevic, Dan

2018-04-01

Underlying nearly every quantitative discussion of the Cygnus Loop supernova remnant is uncertainty about its distance. Here, we present optical images and spectra of nebulosities around two stars whose mass-loss material appears to have interacted with the remnant's expanding shock front and thus can be used to estimate the Cygnus Loop's distance. Narrow passband images reveal a small emission-line nebula surrounding an M4 red giant near the remnant's eastern nebula NGC 6992. Optical spectra of the nebula show it to be shock-heated with significantly higher electron densities than seen in the remnant's filaments. This along with a bow-shaped morphology suggests it is likely red giant mass-loss material shocked and accelerated by passage of the Cygnus Loop's blast wave. We also identify a B7 V star located along the remnant's northwestern limb, which also appears to have interacted with the remnant's shock wave. It lies within a small arc of nebulosity in an unusually complex region of curved and distorted filaments along the remnant's northern shock front suggestive of a localized disturbance of the shock front due to the B star's stellar winds. Based on the assumption that these two stars lie inside the remnant, combined with an estimated distance to a molecular cloud situated along the remnant's western limb, we propose a distance to the Cygnus Loop of 1.0 ± 0.2 kpc. Although larger than several recent estimates of 500-800 pc, a distance ≃1 kpc helps resolve difficulties with the remnant's postshock cosmic ray and gas pressure ratio and estimated supernova explosion energy.

Distance Measurement Solves Astrophysical Mysteries

NASA Astrophysics Data System (ADS)

2003-08-01

Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of

Passion at a Distance

NASA Astrophysics Data System (ADS)

Howard, Don

In 1984, Abner Shimony invented the expression, “passion at a distance,” to characterize the distinctive relationship of two entangled quantum mechanical systems [1]. It is neither the local causality of pushes, pulls, and central forces familiar from classical mechanics and electrodynamics, nor the non-local causality of instantaneous or just superluminal action at a distance that would spell trouble for relativity theory. This mode of connection of entangled systems has them feeling one another's presence and properties enough to ensure the strong correlations revealed in the Bell experiments, correlations that undergird everything from superfluidity and superconductivity to quantum computing and quantum teleportation, but not in a way that permits direct control of one by manipulation of the other. Intended to echo Aristotle's distinguishing of “potentiality” from “actuality” as different senses of “being,” Shimony's “passion at a distance” is all about tendency and propensity, not the concreteness whose misplacement in realm of the physical was lamented by Alfred North Whitehead.

Understanding Long-distance Traveler Behavior : Supporting a Long-distance Passenger Travel Demand Model

DOT National Transportation Integrated Search

2013-01-01

Long-distance trips in the United States can take 2 days or 2 weeks and may involve cars, buses, planes, or all three. Whether for business, to see family, or visit a national park, such a variety of trip characteristics requires a detailed understan...

Student Perceptions of the Distance Education Mode Compared with Face-to-Face Teaching in the University Distance Education Programme

ERIC Educational Resources Information Center

Vásquez Martínez, Claudio Rafael; Girón, Graciela; Bañuelos, Antonio Ayón

2012-01-01

This paper is based on a study of the perceptions of the distance education mode compared with face-to-face teaching on the part of students on the university distance education programme at the University of Antioch over the period from 2001 to 2007. It is not possible to ignore the close links between educational processes and social, economic,…

Distance Education in Asia and the Pacific. Volume II. Proceedings of the Regional Seminar on Distance Education (Bangkok, Thailand, November 26-December 3, 1986).

ERIC Educational Resources Information Center

Asian Development Bank, Manila (Philippines).

The paper presented in this three-part conference report trace the growth and development of distance education in the Asian and Pacific region. Part 1 provides a general review. Part 2 contains the following case studies: "Distance Education in India" (S. P. Mullick); "Distance Education in Indonesia" (Professor Setijadi);…

Distance stereotest using a 3-dimensional monitor for adult subjects.

PubMed

Kim, Jongshin; Yang, Hee Kyung; Kim, Youngmin; Lee, Byoungho; Hwang, Jeong-Min

2011-06-01

To evaluate the validity and test-retest reliability of a contour-based 3-dimensional (3-D) monitor distance stereotest (distance 3-D stereotest) and to measure the maximum horizontal disparity that can be fused with disparity vergence for determining the largest measurable disparity of true stereopsis. Observational case series. Sixty-four normal adult subjects (age range, 23 to 39 years) were recruited. Contour-based circles (crossed disparity, 5000 to 20 seconds of arc; Microsoft Visual Studio C(++) 6.0; Microsoft, Inc, Seattle, Washington, USA) were generated on a 3-D monitor (46-inch stereoscopic display) using polarization glasses and were presented to subjects with normal binocularity at 3 m. While the position of the stimulus changed among 4 possible locations, the subjects were instructed to press the corresponding position of the stimulus on a keypad. The results with the new distance 3-D stereotest were compared with those from the distance Randot stereotest. The results of the distance 3-D stereotest and the distance Randot stereotests were identical in 64% and within 1 disparity level in 97% of normal adults. Scores obtained with the 2 tests showed a statistically significant correlation (r = 0.324, P = .009). The half-width of the 95% limit of agreement was 0.47 log seconds of arc (1.55 octaves) using the distance 3-D stereotest--similar to or better than that obtained with conventional distance stereotests. The maximum binocular disparity that can be fused with vergence was 1828 ± 794 seconds of arc (range, 4000 to 500). The distance 3-D stereotest showed good concordance with the distance Randot stereotest and relatively good test-retest reliability, supporting the validity of the distance 3-D stereotest. The normative data set obtained from the present study can serve as a useful reference for quantitative assessment of a wide range of binocular sensory abnormalities. Copyright © 2011 Elsevier Inc. All rights reserved.

Weighted Distances in Scale-Free Configuration Models

NASA Astrophysics Data System (ADS)

Adriaans, Erwin; Komjáthy, Júlia

2018-01-01

In this paper we study first-passage percolation in the configuration model with empirical degree distribution that follows a power-law with exponent τ \\in (2,3) . We assign independent and identically distributed (i.i.d.) weights to the edges of the graph. We investigate the weighted distance (the length of the shortest weighted path) between two uniformly chosen vertices, called typical distances. When the underlying age-dependent branching process approximating the local neighborhoods of vertices is found to produce infinitely many individuals in finite time—called explosive branching process—Baroni, Hofstad and the second author showed in Baroni et al. (J Appl Probab 54(1):146-164, 2017) that typical distances converge in distribution to a bounded random variable. The order of magnitude of typical distances remained open for the τ \\in (2,3) case when the underlying branching process is not explosive. We close this gap by determining the first order of magnitude of typical distances in this regime for arbitrary, not necessary continuous edge-weight distributions that produce a non-explosive age-dependent branching process with infinite mean power-law offspring distributions. This sequence tends to infinity with the amount of vertices, and, by choosing an appropriate weight distribution, can be tuned to be any growing function that is O(log log n) , where n is the number of vertices in the graph. We show that the result remains valid for the the erased configuration model as well, where we delete loops and any second and further edges between two vertices.

Multi-image acquisition-based distance sensor using agile laser spot beam.

PubMed

Riza, Nabeel A; Amin, M Junaid

2014-09-01

We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance. By exploiting the unique relationship of the target located spot sizes with the varying ECVFL focal length for each target distance, the proposed distance sensor can compute the target distance with a distance measurement resolution better than the axial resolution via the Rayleigh resolution criterion. Using a 30 mW 633 nm He-Ne laser coupled with an electromagnetically actuated liquid ECVFL, along with a 20 cm focal length bias lens, and using five spot images captured per target position by a CCD-based Nikon camera, a proof-of-concept proposed distance sensor is successfully implemented in the laboratory over target ranges from 10 to 100 cm with a demonstrated sub-cm axial resolution, which is better than the axial Rayleigh resolution limit at these target distances. Applications for the proposed potentially cost-effective distance sensor are diverse and include industrial inspection and measurement and 3D object shape mapping and imaging.

Preferred viewing distance and screen angle of electronic paper displays.

PubMed

Shieh, Kong-King; Lee, Der-Song

2007-09-01

This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 495 mm and 123.7 degrees. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4 degrees, significantly greater than that of Sony, 120.0 degrees. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7 degrees, which in terms of viewing angle is 29.5 degrees below horizontal eye level. This result is similar to the general suggested viewing angle between 20 degrees and 50 degrees below the horizontal line of sight.

Maximum nondiffracting propagation distance of aperture-truncated Airy beams

NASA Astrophysics Data System (ADS)

Chu, Xingchun; Zhao, Shanghong; Fang, Yingwu

2018-05-01

Airy beams have called attention of many researchers due to their non-diffracting, self-healing and transverse accelerating properties. A key issue in research of Airy beams and its applications is how to evaluate their nondiffracting propagation distance. In this paper, the critical transverse extent of physically realizable Airy beams is analyzed under the local spatial frequency methodology. The maximum nondiffracting propagation distance of aperture-truncated Airy beams is formulated and analyzed based on their local spatial frequency. The validity of the formula is verified by comparing the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam, aperture-truncated exponentially decaying Airy beam and exponentially decaying Airy beam. Results show that the formula can be used to evaluate accurately the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam. Therefore, it can guide us to select appropriate parameters to generate Airy beams with long nondiffracting propagation distance that have potential application in the fields of laser weapons or optical communications.

Resistance Distances and Kirchhoff Index in Generalised Join Graphs

NASA Astrophysics Data System (ADS)

Chen, Haiyan

2017-03-01

The resistance distance between any two vertices of a connected graph is defined as the effective resistance between them in the electrical network constructed from the graph by replacing each edge with a unit resistor. The Kirchhoff index of a graph is defined as the sum of all the resistance distances between any pair of vertices of the graph. Let G=H[G1, G2, …, Gk ] be the generalised join graph of G1, G2, …, Gk determined by H. In this paper, we first give formulae for resistance distances and Kirchhoff index of G in terms of parameters of {G'_i}s and H. Then, we show that computing resistance distances and Kirchhoff index of G can be decomposed into simpler ones. Finally, we obtain explicit formulae for resistance distances and Kirchhoff index of G when {G'_i}s and H take some special graphs, such as the complete graph, the path, and the cycle.

(On)line dancing: choosing an appropriate distance education partner.

PubMed

Menn, Mindy; Don Chaney, J

2014-05-01

Online-delivered distance education is a burgeoning component of professional development and continuing education. Distance education programs allow individuals to learn in a different location and/or at a different time from fellow learners, thereby increasing the flexibility and number of learning options. Selecting the "right" program for personal development from the ever-growing body of online-delivered education is an individualized decision that can become an overwhelming and challenging process. This Tool presents four important definitions for navigating distance education program description materials and outlines a five-step process to assist in identifying an appropriate program for personal development. The five-step process includes key questions and points to consider while conducting a candid self-assessment, identifying and investigating distance education programs, and then compiling information, comparing programs, and prioritizing a list of programs suitable for application. Furthermore, this Tool highlights important websites for distance education degree program reviews, accreditation information, and open educational resources.

Detecting changes in forced climate attractors with Wasserstein distance

NASA Astrophysics Data System (ADS)

Robin, Yoann; Yiou, Pascal; Naveau, Philippe

2017-07-01

The climate system can been described by a dynamical system and its associated attractor. The dynamics of this attractor depends on the external forcings that influence the climate. Such forcings can affect the mean values or variances, but regions of the attractor that are seldom visited can also be affected. It is an important challenge to measure how the climate attractor responds to different forcings. Currently, the Euclidean distance or similar measures like the Mahalanobis distance have been favored to measure discrepancies between two climatic situations. Those distances do not have a natural building mechanism to take into account the attractor dynamics. In this paper, we argue that a Wasserstein distance, stemming from optimal transport theory, offers an efficient and practical way to discriminate between dynamical systems. After treating a toy example, we explore how the Wasserstein distance can be applied and interpreted to detect non-autonomous dynamics from a Lorenz system driven by seasonal cycles and a warming trend.

Using Computers in Distance Study: Results of a Survey amongst Disabled Distance Students.

ERIC Educational Resources Information Center

Ommerborn, Rainer; Schuemer, Rudolf

2002-01-01

In the euphoria about new technologies in distance education there exists the danger of not sufficiently considering how ever increasing "virtualization" may exclude some student groups. An explorative study was conducted that asked disabled students about their experiences with using computers and the Internet. Overall, those questioned…

Study of probe-sample distance for biomedical spectra measurement.

PubMed

Wang, Bowen; Fan, Shuzhen; Li, Lei; Wang, Cong

2011-11-02

Fiber-based optical spectroscopy has been widely used for biomedical applications. However, the effect of probe-sample distance on the collection efficiency has not been well investigated. In this paper, we presented a theoretical model to maximize the illumination and collection efficiency in designing fiber optic probes for biomedical spectra measurement. This model was in general applicable to probes with single or multiple fibers at an arbitrary incident angle. In order to demonstrate the theory, a fluorescence spectrometer was used to measure the fluorescence of human finger skin at various probe-sample distances. The fluorescence spectrum and the total fluorescence intensity were recorded. The theoretical results show that for single fiber probes, contact measurement always provides the best results. While for multi-fiber probes, there is an optimal probe distance. When a 400- μm excitation fiber is used to deliver the light to the skin and another six 400- μm fibers surrounding the excitation fiber are used to collect the fluorescence signal, the experimental results show that human finger skin has very strong fluorescence between 475 nm and 700 nm under 450 nm excitation. The fluorescence intensity is heavily dependent on the probe-sample distance and there is an optimal probe distance. We investigated a number of probe-sample configurations and found that contact measurement could be the primary choice for single-fiber probes, but was very inefficient for multi-fiber probes. There was an optimal probe-sample distance for multi-fiber probes. By carefully choosing the probe-sample distance, the collection efficiency could be enhanced by 5-10 times. Our experiments demonstrated that the experimental results of the probe-sample distance dependence of collection efficiency in multi-fiber probes were in general agreement with our theory.

Use of Educational Technology in Promoting Distance Education

ERIC Educational Resources Information Center

Rashid, Muhammad; Elahi, Uzma

2012-01-01

Educational technology plays an important role in distance education system. By adapting new communication educational technologies in distance educational programmes their quality could be ensured. Instructions conducted through the use of technologies which significantly or completely eliminate the traditional face to face communication between…

Future Directions in Distance Learning and Communication Technologies

ERIC Educational Resources Information Center

Shih, Timothy; Hung, Jason

2007-01-01

Future Directions in Distance Learning and Communication Technologies presents theoretical studies and practical solutions for engineers, educational professionals, and graduate students in the research areas of e-learning, distance education, and instructional design. This book provides readers with cutting-edge solutions and research directions…

Action Research Projects in Distance Education: A Manual.

ERIC Educational Resources Information Center

Ramakrishna, C. Pushpa; Prasad, V. S.

This manual, prepared by the Distance Education Council (India) presents guidelines for action research in distance education, balancing practical research activities with a sound theoretical research base. Chapter 1, "Scope, Purpose and Design of the Manual," suggests several definitions of research; draws distinctions between academic…

Absolute and relative cues for the auditory perception of egocentric distance.

PubMed

Mershon, D H; Bowers, J N

1979-01-01

Three experiments were performed to examine the reverberation cue to egocentric auditory distance and to determine the extent to which such a cue could provide 'absolute', as contrasted with 'relative', information about distance. In experiment 1 independent groups of blindfolded observers (200 altogether) were presented with broadband noise from a speaker at one of five different distances (0.55 to 8 m) in a normal hard-walled room. Half of each group of observers were presented with the sound at 0 deg azimuth, followed (after a delay) by the identical sound at 90 deg azimuth. The order of presentation was reversed for the remaining observers. Perceived distance varied significantly as a function of the physical distance to the speaker, even for the first presentations. The change in the binaural information between the 0 deg and 90 deg presentations did not significantly modify the results. For both orientations, near distances were overestimated and far distances were underestimated. Experiment 2 and 3 were designed to evaluate how much prior auditory exposure to the laboratory environment was necessary. A 200 Hz square-wave signal was presented from one of three distances (1, 2, or 6 m) to observers who had either minimal room information or an exposure which included talking within the room. Perceived distance varied significantly with physical distance regardless to exposure condition.

Cutting the Distance in Distance Education: Reflections on the Use of E-Technologies in a New Zealand Social Work Program

ERIC Educational Resources Information Center

Stanley-Clarke, Nicky; English, Awhina; Yeung, Polly

2018-01-01

The development of new e-technologies and an increased focus on developing distance social work education programs has created the impetus for social work educators to consider the tools they can employ in delivering distance courses. This article reflects on an action learning research project involving the development of an online toolbox of…

Distance Education Survey, 1996. A Report on Course Structure and Educational Practices in Distance Education and Training Council Member Institutions.

ERIC Educational Resources Information Center

Distance Education and Training Council, Washington, DC.

Course structures and educational practices in Distance Education and Training Council (DETC) member institutions were examined through a survey of all 58 DETC institutions. Usable responses were obtained from 55 (95%) of the institutions. Among the study's main conclusions were the following: (1) 52% of distance education students are male, 42%…

On the weight of indels in genomic distances

PubMed Central

2011-01-01

Background Classical approaches to compute the genomic distance are usually limited to genomes with the same content, without duplicated markers. However, differences in the gene content are frequently observed and can reflect important evolutionary aspects. A few polynomial time algorithms that include genome rearrangements, insertions and deletions (or substitutions) were already proposed. These methods often allow a block of contiguous markers to be inserted, deleted or substituted at once but result in distance functions that do not respect the triangular inequality and hence do not constitute metrics. Results In the present study we discuss the disruption of the triangular inequality in some of the available methods and give a framework to establish an efficient correction for two models recently proposed, one that includes insertions, deletions and double cut and join (DCJ) operations, and one that includes substitutions and DCJ operations. Conclusions We show that the proposed framework establishes the triangular inequality in both distances, by summing a surcharge on indel operations and on substitutions that depends only on the number of markers affected by these operations. This correction can be applied a posteriori, without interfering with the already available formulas to compute these distances. We claim that this correction leads to distances that are biologically more plausible. PMID:22151784

Distance Education Programs in Social Work: Current and Emerging Trends

ERIC Educational Resources Information Center

Vernon, Robert; Vakalahi, Halaevalu; Pierce, Dean; Pittman-Munke, Peggy; Adkins, Lynn Frantz

2009-01-01

This article reports on current and emerging trends in the use of distance education technologies in social work education. Areas studied include the extent of distance education programs, curricular areas covered, technologies used, pedagogical approaches, intentions for degree-program development, sources of pressure to adopt distance education…

Accreditation of Distance Learning

ERIC Educational Resources Information Center

Demirel, Ergün

2016-01-01

The higher education institutes aspire to gain reputation of quality having accreditation from internationally recognized awarding bodies. The accreditation leads and provides quality assurance for education. Although distance learning becomes a significant part of the education system in the 21st century, there is still a common opinion that the…

Misconceptions of Astronomical Distances

ERIC Educational Resources Information Center

Miller, Brian W.; Brewer, William F.

2010-01-01

Previous empirical studies using multiple-choice procedures have suggested that there are misconceptions about the scale of astronomical distances. The present study provides a quantitative estimate of the nature of this misconception among US university students by asking them, in an open-ended response format, to make estimates of the distances…

Factors influencing social distance toward people with mental illness.

PubMed

Lauber, Christoph; Nordt, Carlos; Falcato, Luis; Rössler, Wulf

2004-06-01

When identifying ways to reduce stigmatization because of mental illness it is crucial to understand contributing factors. Social distance-the willingness to engage in relationships of varying intimacy with a person--is an indicator of public attitudes toward persons with mental illness. Multiple linear regression analysis of the results of a vignette-based opinion survey conducted on a representative population sample in Switzerland (n = 594). The level of social distance increases if situations imply 'social closeness.' The vignette describing a person with schizophrenia, attitudes to general aspects of mental health (lay helping, community psychiatry), emotions toward those affected, and the attitude toward consequences of mental illness (medical treatment, medication side effects, negative sanctions, e.g. withdrawal of the driver license) were found to predict social distance. Demographic factors such as age, gender, and the cultural background influence social distance. The explained variance (R2) is 44.8%. Social distance is a multifaceted concept influenced by, e.g., socio-economic and cultural factors, but also by the respondent's general attitude toward (mental) health issues. These results suggest that more knowledge about mental illnesses, especially schizophrenia, may increase social distance. The findings presented here may help to focus anti-stigma campaigns not only on transmission of knowledge, but on integrating different approaches.

Distance measurement using frequency scanning interferometry with mode-hoped laser

NASA Astrophysics Data System (ADS)

Medhat, M.; Sobee, M.; Hussein, H. M.; Terra, O.

2016-06-01

In this paper, frequency scanning interferometry is implemented to measure distances up to 5 m absolutely. The setup consists of a Michelson interferometer, an external cavity tunable diode laser, and an ultra-low expansion (ULE) Fabry-Pérot (FP) cavity to measure the frequency scanning range. The distance is measured by acquiring simultaneously the interference fringes from, the Michelson and the FP interferometers, while scanning the laser frequency. An online fringe processing technique is developed to calculate the distance from the fringe ratio while removing the parts result from the laser mode-hops without significantly affecting the measurement accuracy. This fringe processing method enables accurate distance measurements up to 5 m with measurements repeatability ±3.9×10-6 L. An accurate translation stage is used to find the FP cavity free-spectral-range and therefore allow accurate measurement. Finally, the setup is applied for the short distance calibration of a laser distance meter (LDM).

Adjunct Faculty as Key Stakeholders in Distance Education

ERIC Educational Resources Information Center

Ridge, Alison; Ritt, Elizabeth

2017-01-01

Institutions of higher learning are expanding their academic reach by offering distance education courses and degree programs. Student demand for distance education continues to grow and so does the need for qualified faculty. The literature presents numerous approaches and best practices regarding new faculty orientation and professional…

Distance Learning in British Universities: Is It Possible?

ERIC Educational Resources Information Center

Lentell, Helen

2012-01-01

The wider context (political and economic) for developing sustainable distance learning in UK universities is encouraging and new learning technologies promise much improved products and services. But conventional campus-based universities struggle to build and/or expand sustainable distance learning provision. This article identifies the core…

14 CFR 420.70 - Separation distance measurement requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Separation distance measurement requirements. 420.70 Section 420.70 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... energetic liquids or net explosive weight that requires the greater distance. [Docket No. FAA-2011-0105, 77...

14 CFR 420.70 - Separation distance measurement requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Separation distance measurement requirements. 420.70 Section 420.70 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... energetic liquids or net explosive weight that requires the greater distance. [Docket No. FAA-2011-0105, 77...

Priming of Spatial Distance Enhances Children's Creative Performance

ERIC Educational Resources Information Center

Liberman, Nira; Polack, Orli; Hameiri, Boaz; Blumenfeld, Maayan

2012-01-01

According to construal level theory, psychological distance promotes more abstract thought. Theories of creativity, in turn, suggest that abstract thought promotes creativity. Based on these lines of theorizing, we predicted that spatial distancing would enhance creative performance in elementary school children. To test this prediction, we primed…

The Carnegie-Chicago Hubble Program. I. An Independent Approach to the Extragalactic Distance Scale Using Only Population II Distance Indicators

NASA Astrophysics Data System (ADS)

Beaton, Rachael L.; Freedman, Wendy L.; Madore, Barry F.; Bono, Giuseppe; Carlson, Erika K.; Clementini, Gisella; Durbin, Meredith J.; Garofalo, Alessia; Hatt, Dylan; Jang, In Sung; Kollmeier, Juna A.; Lee, Myung Gyoon; Monson, Andrew J.; Rich, Jeffrey A.; Scowcroft, Victoria; Seibert, Mark; Sturch, Laura; Yang, Soung-Chul

2016-12-01

We present an overview of the Carnegie-Chicago Hubble Program, an ongoing program to obtain a 3% measurement of the Hubble constant (H 0) using alternative methods to the traditional Cepheid distance scale. We aim to establish a completely independent route to H 0 using RR Lyrae variables, the tip of the red giant branch (TRGB), and Type Ia supernovae (SNe Ia). This alternative distance ladder can be applied to galaxies of any Hubble type, of any inclination, and, using old stars in low-density environments, is robust to the degenerate effects of metallicity and interstellar extinction. Given the relatively small number of SNe Ia host galaxies with independently measured distances, these properties provide a great systematic advantage in the measurement of H 0 via the distance ladder. Initially, the accuracy of our value of H 0 will be set by the five Galactic RR Lyrae calibrators with Hubble Space Telescope Fine-Guidance Sensor parallaxes. With Gaia, both the RR Lyrae zero-point and TRGB method will be independently calibrated, the former with at least an order of magnitude more calibrators and the latter directly through parallax measurement of tip red giants. As the first end-to-end “distance ladder” completely independent of both Cepheid variables and the Large Magellanic Cloud, this path to H 0 will allow for the high-precision comparison at each rung of the traditional distance ladder that is necessary to understand tensions between this and other routes to H 0. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs #13472 and #13691.

Collaborative distance learning: Developing an online learning community

NASA Astrophysics Data System (ADS)

Stoytcheva, Maria

2017-12-01

The method of collaborative distance learning has been applied for years in a number of distance learning courses, but they are relatively few in foreign language learning. The context of this research is a hybrid distance learning of French for specific purposes, delivered through the platform UNIV-RcT (Strasbourg University), which combines collaborative activities for the realization of a common problem-solving task online. The study focuses on a couple of aspects: on-line interactions carried out in small, tutored groups and the process of community building online. By analyzing the learner's perceptions of community and collaborative learning, we have tried to understand the process of building and maintenance of online learning community and to see to what extent the collaborative distance learning contribute to the development of the competence expectations at the end of the course. The analysis of the results allows us to distinguish the advantages and limitations of this type of e-learning and thus evaluate their pertinence.

Distance-Dependent Multimodal Image Registration for Agriculture Tasks

PubMed Central

Berenstein, Ron; Hočevar, Marko; Godeša, Tone; Edan, Yael; Ben-Shahar, Ohad

2015-01-01

Image registration is the process of aligning two or more images of the same scene taken at different times; from different viewpoints; and/or by different sensors. This research focuses on developing a practical method for automatic image registration for agricultural systems that use multimodal sensory systems and operate in natural environments. While not limited to any particular modalities; here we focus on systems with visual and thermal sensory inputs. Our approach is based on pre-calibrating a distance-dependent transformation matrix (DDTM) between the sensors; and representing it in a compact way by regressing the distance-dependent coefficients as distance-dependent functions. The DDTM is measured by calculating a projective transformation matrix for varying distances between the sensors and possible targets. To do so we designed a unique experimental setup including unique Artificial Control Points (ACPs) and their detection algorithms for the two sensors. We demonstrate the utility of our approach using different experiments and evaluation criteria. PMID:26308000

The Lorentzian distance formula in noncommutative geometry

NASA Astrophysics Data System (ADS)

Franco, Nicolas

2018-02-01

For almost twenty years, a search for a Lorentzian version of the well-known Connes’ distance formula has been undertaken. Several authors have contributed to this search, providing important milestones, and the time has now come to put those elements together in order to get a valid and functional formula. This paper presents a historical review of the construction and the proof of a Lorentzian distance formula suitable for noncommutative geometry.

Influence of Inter-Electrode Distance on EMG

DTIC Science & Technology

2001-10-25

has been observed that at low levels of muscle contraction there was no significant variation due to the change in the distance between the...a variation of the spectral content of the EMG with change in the IED. The study also has shown that there is a variation of the EMG with muscle ... contraction but that the comparison should be done if the distance between the electrodes has been kept constant.

Student Identity and Authentication in Distance Education: A Primer for Distance Learning Administrators

ERIC Educational Resources Information Center

Aceves, Patricia A.; Aceves, Robert I.

2009-01-01

Since the signing of the Higher Education Opportunity Act (HEOA) in August 2008, providers of distance education courses and programs have been looking into procedures and technologies that will satisfy the accrediting agencies responsible for enforcing the law. Continuing education administrators are at the forefront because of the pervasiveness…

Average geodesic distance of skeleton networks of Sierpinski tetrahedron

NASA Astrophysics Data System (ADS)

Yang, Jinjin; Wang, Songjing; Xi, Lifeng; Ye, Yongchao

2018-04-01

The average distance is concerned in the research of complex networks and is related to Wiener sum which is a topological invariant in chemical graph theory. In this paper, we study the skeleton networks of the Sierpinski tetrahedron, an important self-similar fractal, and obtain their asymptotic formula for average distances. To provide the formula, we develop some technique named finite patterns of integral of geodesic distance on self-similar measure for the Sierpinski tetrahedron.

Inclusive Approach to the Psycho-Pedagogical Assistance of Distance Learning

ERIC Educational Resources Information Center

Akhmetova, Daniya Z.

2014-01-01

Author focuses on three groups of problems: quality of distance learning and e-learning; necessity to develop the facilitation skills for teachers who work using distance learning technologies; realization of inclusive approach for the organization of distance learning in inclusive groups where people with disabilities study with people without…

Monitoring distances travelled by horses using GPS tracking collars.

PubMed

Hampson, B A; Morton, J M; Mills, P C; Trotter, M G; Lamb, D W; Pollitt, C C

2010-05-01

The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. In the paddocks used (0.8-16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.

Squared Euclidean distance: a statistical test to evaluate plant community change

Treesearch

Raymond D. Ratliff; Sylvia R. Mori

1993-01-01

The concepts and a procedure for evaluating plant community change using the squared Euclidean distance (SED) resemblance function are described. Analyses are based on the concept that Euclidean distances constitute a sample from a population of distances between sampling units (SUs) for a specific number of times and SUs. With different times, the distances will be...

Developing Distance Learning Courses in a "Traditional" University.

ERIC Educational Resources Information Center

Lawton, Sally; Barnes, Richard

1998-01-01

Comparison of distance learning that was developed with a business-planning approach (market research, cost-benefit analysis, feasibility study, strategic marketing) with one that did not use these techniques showed that business planning ensures that distance-learning courses are not viewed as a "cheap" option. The method identifies…

Nanoscale Interparticle Distance within Dimers in Solution Measured by Light Scattering

PubMed Central

2017-01-01

We demonstrate a novel approach to quantify the interparticle distance in colloidal dimers using Mie scattering. The interparticle distance is varied in a controlled way by changing the ionic strength of the solution and the magnetic attraction between the particles. The measured scaling behavior is interpreted using an energy–distance model that includes the repulsive electrostatic and attractive magnetic interactions. The center-to-center distances of particles with a 525 nm radius can be determined with a root-mean-square accuracy of 12 nm. The data show that the center-to-center distance is larger by 83 nm compared to perfect spheres. The underlying distance offset can be attributed to repulsion by charged protrusions caused by particle surface roughness. The measurement method accurately quantifies interparticle distances that can be used to study cluster formation and colloid aggregation in complex systems, e.g., in biosensing applications. PMID:29183122

Measuring Long-Distance Romantic Relationships: A Validity Study

ERIC Educational Resources Information Center

Pistole, M. Carole; Roberts, Amber

2011-01-01

This study investigated aspects of construct validity for the scores of a new long-distance romantic relationship measure. A single-factor structure of the long-distance romantic relationship index emerged, with convergent and discriminant evidence of external validity, high internal consistency reliability, and applied utility of the scores.…

Information Policy -- Distance Education: Provider and Victim Libraries.

ERIC Educational Resources Information Center

Heron, Peter; Dugan, Robert E.

1997-01-01

This discussion of information policy focuses on library services for distance education. Topics include the logistics and management of providing library services off-site and/or responding to student requests; and meeting the needs of distance education students for information and library instruction, both students from the member institution…

Current Trends in Distance Education: An Administrative Model

ERIC Educational Resources Information Center

Compora, Daniel P.

2003-01-01

Current practices and procedures of distance education programs at selected institutions in higher education in Ohio were studied. Relevant data was found in the areas of: (1) content of the distance education program's mission statement; (2) needs assessment procedures; (3) student demographics; (4) course acquisition, development, and evaluation…

Research in Distance Education: A System Modeling Approach.

ERIC Educational Resources Information Center

Saba, Farhad; Twitchell, David

1988-01-01

Describes how a computer simulation research method can be used for studying distance education systems. Topics discussed include systems research in distance education; a technique of model development using the System Dynamics approach and DYNAMO simulation language; and a computer simulation of a prototype model. (18 references) (LRW)

Prospect of Distance Learning

ERIC Educational Resources Information Center

Rahman, Monsurur; Karim, Reza; Byramjee, Framarz

2015-01-01

Many educational institutions in the United States are currently offering programs through distance learning, and that trend is rising. In almost all spheres of education a developing country like Bangladesh needs to make available the expertise of the most qualified faculty to her distant people. But the fundamental question remains as to whether…

Distance Learning Case Studies.

ERIC Educational Resources Information Center

Barker, Bruce O.

The Office of Technology Assessment authorized a series of case studies in 1989 to investigate how technologies, services, and programs are implemented in distance education projects. The studies were also intended to look at the role of local, state, and federal agencies, and other public and private entities in providing educational services to…

Long-Distance Wh-Movement and Long-Distance Wh-Movement Avoidance in L2 English: Evidence from French and Bulgarian Speakers

ERIC Educational Resources Information Center

Slavkov, Nikolay

2015-01-01

This article investigates spoken productions of complex questions with long-distance wh-movement in the L2 English of speakers whose first language is (Canadian) French or Bulgarian. Long-distance wh-movement is of interest as it can be argued that it poses difficulty in acquisition due to its syntactic complexity and related high processing load.…

Increased distance of shooting on basketball jump shot.

PubMed

Okazaki, Victor Hugo Alves; Rodacki, André Luiz Félix

2012-01-01

The present study analyzed the effect of increased distance on basketball jump shot outcome and performance. Ten male expert basketball players were filmed and a number of kinematic variables analyzed during jump shot that were performed from three conditions to represent close, intermediate and far distances (2.8, 4.6, and 6.4m, respectively). Shot accuracy decreased from 59% (close) to 37% (far), in function of the task constraints (p < 0.05). Ball release height decreased (p < 0.05) from 2.46 m (close) to 2.38m (intermediate) and to 2.33m (long). Release angle also decreased (p < 0.05) when shot was performed from close (78.92°) in comparison to intermediate distances (65.60°). While, ball release velocity increased (p < 0.05) from 4.39 m/s (close) to 5.75 m·s(-1) (intermediate) to 6.89 m·s(-1) (far). These changes in ball release height, angle and velocity, related to movement performance adaptations were suggested as the main factors that influence jump shot accuracy when distance is augmented. Key pointsThe increased distance leads to greater spatial con-straint over shot movement that demands an adapta-tion of the movement for the regulation of the accu-racy and the impulse generation to release the ball.The reduction in balls release height and release angle, in addition to the increase in balls release ve-locity, were suggested as the main factors that de-creased shot accuracy with the distance increased.Players should look for release angles of shooting that provide an optimal balls release velocity to im-prove accuracy.

Distance Decay of Similarity in Neotropical Diatom Communities

PubMed Central

Wetzel, Carlos E.; Bicudo, Denise de C.; Ector, Luc; Lobo, Eduardo A.; Soininen, Janne; Landeiro, Victor L.; Bini, Luis M.

2012-01-01

Background The regression of similarity against distance unites several ecological phenomena, and thus provides a highly useful approach for illustrating the spatial turnover across sites. Our aim was to test whether the rates of decay in community similarity differ between diatom growth forms suggested to show different dispersal ability. We hypothesized that the diatom group with lower dispersal ability (i.e. periphyton) would show higher distance decay rates than a group with higher dispersal ability (i.e. plankton). Methods/Principal findings Periphyton and phytoplankton samples were gathered at sites distributed over an area of approximately 800 km length in the Negro River, Amazon basin, Brazil, South America (3°08′00″S; 59°54′30″W). Distance decay relationships were then estimated using distance-based regressions, and the coefficients of these regressions were compared among the groups with different dispersal abilities to assess our predictions. We found evidence that different tributaries and reaches of the Negro River harbor different diatom communities. As expected, the rates of distance decay in community similarity were higher for periphyton than for phytoplankton indicating the lower dispersal ability of periphytic taxa. Conclusions/Significance Our study demonstrates that the comparison of distance decay relationships among taxa with similar ecological requirements, but with different growth form and thus dispersal ability provides a sound approach to evaluate the effects of dispersal ability on beta diversity patterns. Our results are also in line with the growing body of evidence indicating that microorganisms exhibit biogeographic patterns. Finally, we underscore that clumbing all microbial taxa into one group may be a flawed approach to test whether microbes exhibit biogeographic patterns. PMID:23028767

Problems and Prospects of Open and Distance Education in Nigeria

ERIC Educational Resources Information Center

Yusuf, Mudasiru Olalere

2006-01-01

Distance education as a mean of providing access to education, particularly tertiary level education, has gained great prominence in the world. Nigeria has taken giant steps of recent to introduce open and distance education programme. This paper explores the major terms inherent in open and distance education, its potentials, possible factors…

Neuroticism as Distancing: Perceptual Sources of Evidence

PubMed Central

Liu, Tianwei; Ode, Scott; Moeller, Sara K.; Robinson, Michael D.

2013-01-01

Several theories and self-reported sources of data link individual differences in negative affectivity to avoidance motivation. Chronic avoidance motivation, through repeated practice, may result in a relatively cognitive distance-enhancing dynamic whereby events and stimuli are perceived as further away from the self, even when they are not threatening. Such predictions are novel, but follow from cybernetic theories of self-regulation. In five studies (total N = 463), relations of this type were investigated. Study 1 presented participants with phrases that were ambiguous and found that trait negative affect predicted phrase interpretation in a distance-enhancing temporal direction. Study 2 replicated this effect across a systematic manipulation of event valence. Study 3 asked individuals to estimate the size of words and found that individuals higher in neuroticism generally perceived words to be smaller than did individuals lower in neuroticism. In Study 4, people high (but not low) in neuroticism perceived words to be shrinking faster than they were growing. In Study 5, greater perceptual distancing, in a font size estimation task, predicted more adverse reactions to negative events in daily life. Although normative effects varied across studies, consistent support for a chronic distancing perspective of individual differences in negative affectivity was found. PMID:23527850

Neuroticism as distancing: perceptual sources of evidence.

PubMed

Liu, Tianwei; Ode, Scott; Moeller, Sara K; Robinson, Michael D

2013-05-01

Several theories and self-reported sources of data link individual differences in negative affectivity to avoidance motivation. Chronic avoidance motivation, through repeated practice, may result in a relatively cognitive distance-enhancing dynamic whereby events and stimuli are perceived as further away from the self, even when they are not threatening. Such predictions are novel but follow from cybernetic theories of self-regulation. In 5 studies (total N = 463), relations of this type were investigated. Study 1 presented participants with phrases that were ambiguous and found that trait negative affect predicted phrase interpretation in a distance-enhancing temporal direction. Study 2 replicated this effect across a systematic manipulation of event valence. Study 3 asked individuals to estimate the size of words and found that individuals higher in neuroticism generally perceived words to be smaller than did individuals lower in neuroticism. In Study 4, people high (but not low) in neuroticism perceived words to be shrinking faster than they were growing. In Study 5, greater perceptual distancing, in a font size estimation task, predicted more adverse reactions to negative events in daily life. Although normative effects varied across studies, consistent support for a chronic distancing perspective of individual differences in negative affectivity was found. PsycINFO Database Record (c) 2013 APA, all rights reserved

Optimal architectures for long distance quantum communication.

PubMed

Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

2016-02-15

Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥ 1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances.

Optimal architectures for long distance quantum communication

PubMed Central

Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D.; Jiang, Liang

2016-01-01

Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances. PMID:26876670

Optimal architectures for long distance quantum communication

NASA Astrophysics Data System (ADS)

Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D.; Jiang, Liang

2016-02-01

Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances.

Fire safety distances for open pool fires

NASA Astrophysics Data System (ADS)

Sudheer, S.; Kumar, Lokendra; Manjunath, B. S.; Pasi, Amit; Meenakshi, G.; Prabhu, S. V.

2013-11-01

Fire accidents that carry huge loss with them have increased in the previous two decades than at any time in the history. Hence, there is a need for understanding the safety distances from different fires with different fuels. Fire safety distances are computed for different open pool fires. Diesel, gasoline and hexane are used as fuels for circular pool diameters of 0.5 m, 0.7 m and 1.0 m. A large square pool fire of 4 m × 4 m is also conducted with diesel as a fuel. All the prescribed distances in this study are purely based on the thermal analysis. IR camera is used to get the thermal images of pool fires and there by the irradiance at different locations is computed. The computed irradiance is presented with the threshold heat flux limits for human beings.

Using Computers in Distance Study: Results of a Survey amongst Disabled Distance Students.

ERIC Educational Resources Information Center

Ommerborn, Rainer; Schuemer, Rudolf

A study at Germany's FernUniversitat sent a questionnaire to 300 enrolled distance education students (mostly adult, mostly part-time) who labeled themselves as severely disabled or chronically ill (about 2 percent of students), asking them about the types of their disabilities and their attitudes toward computer-assisted learning and online…

Open and Distance Learning in the Developing World. Routledge Studies in Distance Education.

ERIC Educational Resources Information Center

Perraton, Hilary

This book contains 10 chapters that analyze and synthesize the progress of open and distance education (ODE) in the developing world. Most chapters include case studies of programs in a variety of countries. "Introduction: Golden Goose or Ugly Duckling" briefly delineates the history of the field. "Nonformal Education: The Light…

Distance bounded energy detecting ultra-wideband impulse radio secure protocol.

PubMed

Hedin, Daniel S; Kollmann, Daniel T; Gibson, Paul L; Riehle, Timothy H; Seifert, Gregory J

2014-01-01

We present a demonstration of a novel protocol for secure transmissions on a Ultra-wideband impulse radio that includes distance bounding. Distance bounding requires radios to be within a certain radius to communicate. This new protocol can be used in body area networks for medical devices where security is imperative. Many current wireless medical devices were not designed with security as a priority including devices that can be life threatening if controlled by a hacker. This protocol provides multiple levels of security including encryption and a distance bounding test to prevent long distance attacks.

MHEG Based Distance Learning System on Information Superhighway.

ERIC Educational Resources Information Center

Lee, SeiHoon; Yoon, KyungSeob; Wang, ChangJong

As the need for distance education grows, requirements for the development of high-speed network-based real-time distance learning systems increases. MHEG-5 is the fifth part of the MHEG (Multimedia and Hypermedia information coding Experts Group) standard, and it defines a final-form representation for application interchange. This paper…

Designing, Developing and Implementing WWW-Based Distance Learning.

ERIC Educational Resources Information Center

Riley, Peter C.

The rapid advancement of communication technologies is resulting in a wide array of design and development choices for distance learning projects. The 58th Special Operations Wing at Kirtland Air Force Base, New Mexico, is developing a prototype distance learning project designed to serve geographically separated learner populations. Project staff…

Embedded Creativity: Teaching Design Thinking via Distance Education

ERIC Educational Resources Information Center

Lloyd, Peter

2013-01-01

This paper shows how the design thinking skills of students learning at a distance can be consciously developed, and deliberately applied outside of the creative industries in what are termed 'embedded' contexts. The distance learning model of education pioneered by The Open University is briefly described before the technological…

14 CFR 29.81 - Landing distance: Category A.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing distance: Category A. 29.81 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.81 Landing distance: Category A... knots for water landings) from a point 50 ft above the landing surface must be determined from the...

14 CFR 29.81 - Landing distance: Category A.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing distance: Category A. 29.81 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.81 Landing distance: Category A... knots for water landings) from a point 50 ft above the landing surface must be determined from the...

Strategies for Maintaining Quality in Distance Higher Education

ERIC Educational Resources Information Center

Malik, Sufiana Khatoon

2015-01-01

The current paper was produced with the purpose of suggesting strategies for bringing quality in distance education programs at higher education level. In recent times distance education is becoming an indispensable part of education system globally. Every institution is trying to offer their educational course through general as well through…

Online Pedagogy: Principles for Supporting Effective Distance Education

ERIC Educational Resources Information Center

Scheer, Stephanie B.; Terry, Krista P.; Doolittle, Peter E.; Hicks, David

2004-01-01

Distance education has become a major form of education in the United States. This surge in popularity has launched a plethora of scholarship emphasizing the distillation of those strategies which inform effective, learning experiences in the distance environment. A growing consensus among researchers recognizes the need for a holistic approach to…

The School Problem-Solver's Guide to Distance Education.

ERIC Educational Resources Information Center

Levinson, Cynthia Y.

Many administrators are meeting specific instructional needs of their students without always or solely relying on classroom teachers by utilizing distance education, i.e., instruction that takes place while the learner is physically distant from the instructor and/or the materials. Distance education is particularly appropriate in rural and small…

Practical Staff Management Techniques for Distance Education Coordinators

ERIC Educational Resources Information Center

Porter, Toccara D.

2016-01-01

This article reports on the author's enrollment in the SuccessfUL Supervisor Series course. As a new distance education library coordinator the author sought out formal supervisor training to address staff misconduct and establish staff training initiatives for distance library service needs. Structured as a case study, the author discusses how…

Should Andover College Add a Distance Education Program?

ERIC Educational Resources Information Center

Woodbury, Amanda L.

Adding distance education would provide Andover College with unlimited growth and potentially increased revenue. Andover has three groups of students: nontraditional evening students aged 25-59 who want a degree to advance in their careers; traditional students aged 17-24; and certificate candidates. A distance program would make classes more…

Mobile Learning in Distance Education: Utility or Futility?

ERIC Educational Resources Information Center

Koole, Marguerite; McQuilkin, Janice Letkeman; Ally, Mohamed

2010-01-01

Can mobile technology improve flexibility and quality of interaction for graduate students in distance programs? This paper reports the results of an innovative study exploring the usability, learning, and social interaction of mobile access to online course materials at a Canadian distance education university. Through a system called MobiGlam,…

Research in Distance Education: A System Modeling Approach.

ERIC Educational Resources Information Center

Saba, Farhad; Twitchell, David

This demonstration of the use of a computer simulation research method based on the System Dynamics modeling technique for studying distance education reviews research methods in distance education, including the broad categories of conceptual and case studies, and presents a rationale for the application of systems research in this area. The…

Contact- and distance-based principal component analysis of protein dynamics.

PubMed

Ernst, Matthias; Sittel, Florian; Stock, Gerhard

2015-12-28

To interpret molecular dynamics simulations of complex systems, systematic dimensionality reduction methods such as principal component analysis (PCA) represent a well-established and popular approach. Apart from Cartesian coordinates, internal coordinates, e.g., backbone dihedral angles or various kinds of distances, may be used as input data in a PCA. Adopting two well-known model problems, folding of villin headpiece and the functional dynamics of BPTI, a systematic study of PCA using distance-based measures is presented which employs distances between Cα-atoms as well as distances between inter-residue contacts including side chains. While this approach seems prohibitive for larger systems due to the quadratic scaling of the number of distances with the size of the molecule, it is shown that it is sufficient (and sometimes even better) to include only relatively few selected distances in the analysis. The quality of the PCA is assessed by considering the resolution of the resulting free energy landscape (to identify metastable conformational states and barriers) and the decay behavior of the corresponding autocorrelation functions (to test the time scale separation of the PCA). By comparing results obtained with distance-based, dihedral angle, and Cartesian coordinates, the study shows that the choice of input variables may drastically influence the outcome of a PCA.

Contact- and distance-based principal component analysis of protein dynamics

NASA Astrophysics Data System (ADS)

Ernst, Matthias; Sittel, Florian; Stock, Gerhard

2015-12-01

To interpret molecular dynamics simulations of complex systems, systematic dimensionality reduction methods such as principal component analysis (PCA) represent a well-established and popular approach. Apart from Cartesian coordinates, internal coordinates, e.g., backbone dihedral angles or various kinds of distances, may be used as input data in a PCA. Adopting two well-known model problems, folding of villin headpiece and the functional dynamics of BPTI, a systematic study of PCA using distance-based measures is presented which employs distances between Cα-atoms as well as distances between inter-residue contacts including side chains. While this approach seems prohibitive for larger systems due to the quadratic scaling of the number of distances with the size of the molecule, it is shown that it is sufficient (and sometimes even better) to include only relatively few selected distances in the analysis. The quality of the PCA is assessed by considering the resolution of the resulting free energy landscape (to identify metastable conformational states and barriers) and the decay behavior of the corresponding autocorrelation functions (to test the time scale separation of the PCA). By comparing results obtained with distance-based, dihedral angle, and Cartesian coordinates, the study shows that the choice of input variables may drastically influence the outcome of a PCA.

Understanding auditory distance estimation by humpback whales: a computational approach.

PubMed

Mercado, E; Green, S R; Schneider, J N

2008-02-01

Ranging, the ability to judge the distance to a sound source, depends on the presence of predictable patterns of attenuation. We measured long-range sound propagation in coastal waters to assess whether humpback whales might use frequency degradation cues to range singing whales. Two types of neural networks, a multi-layer and a single-layer perceptron, were trained to classify recorded sounds by distance traveled based on their frequency content. The multi-layer network successfully classified received sounds, demonstrating that the distorting effects of underwater propagation on frequency content provide sufficient cues to estimate source distance. Normalizing received sounds with respect to ambient noise levels increased the accuracy of distance estimates by single-layer perceptrons, indicating that familiarity with background noise can potentially improve a listening whale's ability to range. To assess whether frequency patterns predictive of source distance were likely to be perceived by whales, recordings were pre-processed using a computational model of the humpback whale's peripheral auditory system. Although signals processed with this model contained less information than the original recordings, neural networks trained with these physiologically based representations estimated source distance more accurately, suggesting that listening whales should be able to range singers using distance-dependent changes in frequency content.

Perceived Quality Dimensions in Distance Education: Excerpts from Student Experiences

ERIC Educational Resources Information Center

Thapliyal, Upasna

2014-01-01

Distance education by its nature differs from the regular mode of higher education. A viable option for providing access to higher education for students who cannot attend traditional, on-campus courses, distance education, often gets a tag of being sedentary. This puts into question the qualitative aspect of the distance education courses.…

Deriving the Hirshfeld partitioning using distance metrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidar-Zadeh, Farnaz; Ayers, Paul W., E-mail: ayers@mcmaster.ca; Bultinck, Patrick

2014-09-07

The atoms in molecules associated with the Hirshfeld partitioning minimize the generalized Hellinger-Bhattacharya distance to the reference pro-atom densities. Moreover, the reference pro-atoms can be chosen by minimizing the distance between the pro-molecule density and the true molecular density. This provides an alternative to both the heuristic “stockholder” and the mathematical information-theoretic interpretations of the Hirshfeld partitioning. These results extend to any member of the family of f-divergences.

Measuring the Accuracy of Simple Evolving Connectionist System with Varying Distance Formulas

NASA Astrophysics Data System (ADS)

Al-Khowarizmi; Sitompul, O. S.; Suherman; Nababan, E. B.

2017-12-01

Simple Evolving Connectionist System (SECoS) is a minimal implementation of Evolving Connectionist Systems (ECoS) in artificial neural networks. The three-layer network architecture of the SECoS could be built based on the given input. In this study, the activation value for the SECoS learning process, which is commonly calculated using normalized Hamming distance, is also calculated using normalized Manhattan distance and normalized Euclidean distance in order to compare the smallest error value and best learning rate obtained. The accuracy of measurement resulted by the three distance formulas are calculated using mean absolute percentage error. In the training phase with several parameters, such as sensitivity threshold, error threshold, first learning rate, and second learning rate, it was found that normalized Euclidean distance is more accurate than both normalized Hamming distance and normalized Manhattan distance. In the case of beta fibrinogen gene -455 G/A polymorphism patients used as training data, the highest mean absolute percentage error value is obtained with normalized Manhattan distance compared to normalized Euclidean distance and normalized Hamming distance. However, the differences are very small that it can be concluded that the three distance formulas used in SECoS do not have a significant effect on the accuracy of the training results.

The determination of pair-distance distribution by double electron-electron resonance: regularization by the length of distance discretization with Monte Carlo calculations

NASA Astrophysics Data System (ADS)

Dzuba, Sergei A.

2016-08-01

Pulsed double electron-electron resonance technique (DEER, or PELDOR) is applied to study conformations and aggregation of peptides, proteins, nucleic acids, and other macromolecules. For a pair of spin labels, experimental data allows for the determination of their distance distribution function, P(r). P(r) is derived as a solution of a first-kind Fredholm integral equation, which is an ill-posed problem. Here, we suggest regularization by increasing the distance discretization length to its upper limit where numerical integration still provides agreement with experiment. This upper limit is found to be well above the lower limit for which the solution instability appears because of the ill-posed nature of the problem. For solving the integral equation, Monte Carlo trials of P(r) functions are employed; this method has an obvious advantage of the fulfillment of the non-negativity constraint for P(r). The regularization by the increasing of distance discretization length for the case of overlapping broad and narrow distributions may be employed selectively, with this length being different for different distance ranges. The approach is checked for model distance distributions and for experimental data taken from literature for doubly spin-labeled DNA and peptide antibiotics.

The visual perception of distance ratios in physical space.

PubMed

Norman, J Farley; Adkins, Olivia C; Pedersen, Lauren E

2016-06-01

Past studies have consistently demonstrated that human observers cannot accurately perceive environmental distances. Even so, we obviously detect sufficient spatial information to meet the demands of everyday life. In the current experiment, ten younger adults (mean age was 21.8years) and ten older adults (mean age was 72.3years) estimated distance ratios in physical space. On any given trial, observers judged how long one distance interval was relative to another. The 18 stimulus ratios ranged from 1.0 to 9.5; the observers judged each stimulus ratio three times. The average correlation coefficient relating actual distance ratios to perceived ratios was identical (r=0.87) for both younger and older age groups. Despite this strong relationship between perception and reality, the judgments of many individual observers were inaccurate. For example, ten percent of the observers overestimated the stimulus ratios, while fifty percent underestimated the stimulus ratios. Although both under- and overestimation occurred in the current experiment, the results nevertheless demonstrate that human adults can reliably compare environmental distances in different directions. Copyright © 2016 Elsevier Ltd. All rights reserved.

A distance learning model in a physical therapy curriculum.

PubMed

English, T; Harrison, A L; Hart, A L

1998-01-01

In response to the rural health initiative established in 1991, the University of Kentucky has developed an innovative distance learning program of physical therapy instruction that combines classroom lecture and discussion via compressed video technology with laboratory experiences. The authors describe the process of planning, implementing, and evaluating a specific distance learning course in pathomechanics for the professional-level master's-degree physical therapy students at the University of Kentucky. This presentation may serve as a model for teaching distance learning. Descriptions of optimal approaches to preclass preparation, scheduling, course delivery, use of audiovisual aids, use of handout material, and video production are given. Special activities that may enhance or deter the achievement of the learning objectives are outlined, and a problem-solving approach to common problems encountered is presented. An approach to evaluating and comparing course outcomes for the distance learnere is presented. For this particular course, there was no statistically significant difference in the outcome measures utilized to compare the distance learners with the on-site learners.

Distance Learning '99. Proceedings of the Annual Conference on Distance Teaching and Learning (15th, Madison, Wisconsin, August 4-6, 1999).

ERIC Educational Resources Information Center

Wisconsin Univ. System, Madison.

This document contains 71 papers and 11 workshop presentations on distance teaching and learning from a conference on educational research. The following are among the papers included: "Bridging Distances and Differences" (Nancy Anderson); "The Role of Site Directors in Faculty and Student Success" (Edith M. Barnett, Jeanie P.…

HEARING IMPAIRMENT AND HYPERTENSION AMONG LONG DISTANCE BUS DRIVERS

PubMed Central

Abdelmoneim, Ismail

2003-01-01

Objectives: To investigate the prevalence of possible hearing impairment and hypertension in long distance bus drivers compared to the city bus drivers in Abha city. Methods: This was a cross-sectional study involving 62 long distance bus drivers and 46 city bus drivers from October 2001 to March 2002. A specially-designed questionnaire was administered to the drivers to explore some of their socioeconomic backgrounds. A pure tone air conduction audiometry and blood pressure measurements were performed. Results: Long distance bus drivers’ workload is significantly higher than that of city drivers (total weekly hours 64.0±14.3 compared to 46.7±5.5). Hearing impairment was significantly more among long distance drivers in the frequencies of 250, 500, 1000 and 2000 Hz especially in the left ear even after age corrections. The prevalence of mild hearing loss and hypertension were also higher among the long distance drivers (19.4% vs 4.5% and 38.7% vs 13% respectively). Conclusion and recommendations: This study showed more hearing affection and a higher prevalence of hypertension among long distance bus drivers than their counterparts operating in the city. Their hearing acuity should be tested before they start work and regularly afterwards. The stresses and strains of the job should be further studied and relieved; and regular health checks including blood pressure monitoring are to be instituted. PMID:23012034

The relationship of travel distance with cystectomy access and outcomes.

PubMed

Smith, Angela B; Meyer, Anne-Marie; Meng, Ke; Nielsen, Matthew E; Pruthi, Raj; Wallen, Eric; Woods, Michael; Tan, Hung-Jui

2018-06-01

Regionalization of care and travel distance may result in unintended consequences for complex surgery such as cystectomy. Our objective was to evaluate effect of differential distance on cystectomy receipt among patients with muscle-invasive bladder cancer (MIBC) and investigate the association between travel distance and cystectomy outcomes such as readmission. Using a linked data resource combining the NC Central Cancer Registry with claims data from Medicare, Medicaid, and private insurance plans, we included 736 patients with MIBC and 1,082 who underwent cystectomy. To evaluate access, differential distance was calculated as the difference between the nearest urologist and nearest cystectomy provider. To assess outcomes, logistic regression was used to evaluate rehospitalization and major complications, and Cox proportional hazards model for survival analysis. To evaluate access and outcomes, 736 patients with MIBC and 1,082 patients undergoing cystectomy were evaluated, respectively. Overall, 29% (211 of 736) with MIBC underwent cystectomy. Differential distance was not a predictor of cystectomy receipt (odds ratio = 1.0; 95% CI: 1.00, 1.01). Among patients undergoing cystectomy, travel distance from cystectomy provider was not a significant predictor of 30- or 31 to 90day readmissions (odds ratio = 1.0; 95% CI: 1.00, 1.00) although patients who lived further from their cystectomy provider were more likely to be readmitted to a nonindex hospital (P<0.001) when controlling for other factors. Although travel distance did not have a significant effect on overall survival, patients readmitted between 31 to 90days had worse overall survival (P<0.0001). The additional distance needed to reach a cystectomy provider did not predict receipt of surgery for MIBC. Furthermore, travel distance from cystectomy provider was not a significant predictor for subsequent readmission after cystectomy and did not affect overall survival. Copyright © 2018 Elsevier Inc. All rights

Distance Education Quality Course Delivery Framework: A Formative Research Study

ERIC Educational Resources Information Center

Berta, Michael Raymond

2013-01-01

In the Fall 2010 semester, student enrollment in distance education courses increased in the United States to over 6.1 million students taking at least one distance course. Distance education allows institutions to meet increasing demands from the government and business sectors for more graduates in ways that face-to-face courses cannot meet with…

The effect of viewing distance on observer performance in skeletal radiographs

NASA Astrophysics Data System (ADS)

Butler, M. L.; Lowe, J.; Toomey, R. J.; Maher, M.; Evanoff, M. E.; Rainford, L.

2013-03-01

A number of different viewing distances are recommended by international agencies, however none with specific reference to radiologist performance. The purpose of this study was to ascertain the extent to which radiologists performance is affected by viewing distance on softcopy skeletal reporting. Eighty dorsi-palmar (DP) wrist radiographs, of which half feature 1 or more fractures, were viewed by seven observers at 2 viewing distances, 30cm and 70cm. Observers rated the images as normal or not on a scale of 1 to 5 and could mark multiple locations on the images when they visualised a fracture. Viewing distance was measured from the centre of the face plate to the outer canthus of the eye. The DBM MRM analysis showed no statistically significant differences between the area under the curve for the two distances (p = 0.482). The JAFROC analysis, however, demonstrated a statistically significantly higher area under the curve with the 30cm viewing distance than with the 70 cm distance (p = 0.035). This suggests that while observers were able to make decisions about whether an image contained a fracture or not equally well at both viewing distances, they may have been less reliable in terms of fracture localisation or detection of multiple fractures. The impact of viewing distance warrants further attention from both clinical and scientific perspectives.

Overlapping community detection based on link graph using distance dynamics

NASA Astrophysics Data System (ADS)

Chen, Lei; Zhang, Jing; Cai, Li-Jun

2018-01-01

The distance dynamics model was recently proposed to detect the disjoint community of a complex network. To identify the overlapping structure of a network using the distance dynamics model, an overlapping community detection algorithm, called L-Attractor, is proposed in this paper. The process of L-Attractor mainly consists of three phases. In the first phase, L-Attractor transforms the original graph to a link graph (a new edge graph) to assure that one node has multiple distances. In the second phase, using the improved distance dynamics model, a dynamic interaction process is introduced to simulate the distance dynamics (shrink or stretch). Through the dynamic interaction process, all distances converge, and the disjoint community structure of the link graph naturally manifests itself. In the third phase, a recovery method is designed to convert the disjoint community structure of the link graph to the overlapping community structure of the original graph. Extensive experiments are conducted on the LFR benchmark networks as well as real-world networks. Based on the results, our algorithm demonstrates higher accuracy and quality than other state-of-the-art algorithms.

Beyond the Text: Contemporary Writing on Distance Education.

ERIC Educational Resources Information Center

Evans, Terry; King, Bruce

Based on materials originally prepared for a course being developed at an Australian university, this book examines critical issues in distance education and open learning. The book is organized in five parts. The first part locates distance education in relation to education and social science and provides a general introduction and orientation.…

Deconfounding Distance Effects in Judgments of Moral Obligation

ERIC Educational Resources Information Center

Nagel, Jonas; Waldmann, Michael R.

2013-01-01

A heavily disputed question of moral philosophy is whether spatial distance between agent and victim is normatively relevant for the degree of obligation to help strangers in need. In this research, we focus on the associated descriptive question whether increased distance does in fact reduce individuals' sense of helping obligation. One problem…

Challenging the "Distance Education Deficit" through "Motivational Emails"

ERIC Educational Resources Information Center

Inkelaar, Tom; Simpson, Ormond

2015-01-01

Graduation rates in distance higher education are low compared with full-time higher education--often less than 20% compared with full-time UK rates of around 80%--the "distance education deficit". In the University of London International Programmes, the difference between the face-to-face graduation rate of 61.5% and the distance…

Providing Quality Laboratories to Long-Distance Educational Programs.

ERIC Educational Resources Information Center

Gammon, Tammy; Sutton, John

2003-01-01

North Carolina State University (UNC) has been on the forefront of long-distance education by offering a Bachelor of Science in Engineering with a Mechatronics Concentration at its remote campus located at UNC Asheville. The program demonstrates that long-distance laboratories are feasible and should not be a stumbling block to offering…

Distance Education in China: Connecting Millions for Knowledge

ERIC Educational Resources Information Center

Li, Xiaobin

2013-01-01

Chinese education has a long history, and the Chinese higher education system is the largest in the world, but distance higher education in China started later than it did in developed countries. This article provides an overview of the recent distance higher education development in China. Specifically, the article discusses the positive impact…

The State of Distance Education in Saudi Arabia

ERIC Educational Resources Information Center

Alshmari, Ayshah

2017-01-01

This article provides an overview of the role of distance learning within Saudi Arabia by first briefly introducing the country itself, a general overview of the traditional education system currently in use within the country, and then an examination of the status of distance education in Saudi higher educational settings. Insight into how…

Educational Technology in Distance Learning (for the Deaf).

ERIC Educational Resources Information Center

Hales, Gerald

This discussion of the use of distance education for deaf students argues that distance education methodologies appear to be relatively attractive to the hearing impaired student because they rely to a substantial extent upon the written word and visual transmission of information. Several projects that use computer or interactive systems to teach…

Exercises on Distance Decay Using Mental Health Historical Data.

ERIC Educational Resources Information Center

Hunter, John M.; Shannon, Gary W.

1984-01-01

By analyzing nineteenth-century mental health data, college level geography students discover the concept of distance decay, which describes the decrease in intensity of a phenomenon with increasing distance from some central place. (RM)

Relationship between Social Media and Academic Performance in Distance Education

ERIC Educational Resources Information Center

Gupta, C. A. Pallavi; Singh, Bharti; Marwaha, Tushar

2013-01-01

The scope and method of imparting distance education to the learner has evolved over a period of time. Various models of distance education have been introduced over the years; the latest introduction is the use of Web 2.0 technologies to make distance learning more analytical, flexible, interactive, and collaborative for both the teacher and the…

Spontaneous Self-Distancing and Adaptive Self-Reflection Across Adolescence

PubMed Central

White, Rachel E.; Kross, Ethan; Duckworth, Angela L.

2015-01-01

Experiments performed primarily with adults show that self-distancing facilitates adaptive self-reflection. However, no research has investigated whether adolescents spontaneously engage in this process or whether doing so is linked to adaptive outcomes. In this study, 226 African American adolescents, aged 11 to 20, reflected on an anger-related interpersonal experience. As expected, spontaneous self-distancing during reflection predicted lower levels of emotional reactivity by leading adolescents to reconstrue (rather than recount) their experience and blame their partner less. Moreover, the inverse relation between self-distancing and emotional reactivity strengthened with age. These findings highlight the role that self-distancing plays in fostering adaptive self-reflection in adolescence, and begin to elucidate the role that development plays in enhancing the benefits of engaging in this process. PMID:25876213