Neutron fraction and neutrino mean free path predictions in relativistic mean field models

International Nuclear Information System (INIS)

Hutauruk, P.T.P.; Williams, C.K.; Sulaksono, A.; Mart, T.

2004-01-01

The equation of state (EOS) of dense matter and neutrino mean free path (NMFP) in a neutron star have been studied by using relativistic mean field models motivated by effective field theory. It is found that the models predict too large proton fractions, although one of the models (G2) predicts an acceptable EOS. This is caused by the isovector terms. Except G2, the other two models predict anomalous NMFP's. In order to minimize the anomaly, besides an acceptable EOS, a large M* is favorable. A model with large M* retains the regularity in the NMFP even for a small neutron fraction

A Meta-Path-Based Prediction Method for Human miRNA-Target Association

Directory of Open Access Journals (Sweden)

Jiawei Luo

2016-01-01

Full Text Available MicroRNAs (miRNAs are short noncoding RNAs that play important roles in regulating gene expressing, and the perturbed miRNAs are often associated with development and tumorigenesis as they have effects on their target mRNA. Predicting potential miRNA-target associations from multiple types of genomic data is a considerable problem in the bioinformatics research. However, most of the existing methods did not fully use the experimentally validated miRNA-mRNA interactions. Here, we developed RMLM and RMLMSe to predict the relationship between miRNAs and their targets. RMLM and RMLMSe are global approaches as they can reconstruct the missing associations for all the miRNA-target simultaneously and RMLMSe demonstrates that the integration of sequence information can improve the performance of RMLM. In RMLM, we use RM measure to evaluate different relatedness between miRNA and its target based on different meta-paths; logistic regression and MLE method are employed to estimate the weight of different meta-paths. In RMLMSe, sequence information is utilized to improve the performance of RMLM. Here, we carry on fivefold cross validation and pathway enrichment analysis to prove the performance of our methods. The fivefold experiments show that our methods have higher AUC scores compared with other methods and the integration of sequence information can improve the performance of miRNA-target association prediction.

Path Loss Prediction Over the Lunar Surface Utilizing a Modified Longley-Rice Irregular Terrain Model

Science.gov (United States)

Foore, Larry; Ida, Nathan

2007-01-01

This study introduces the use of a modified Longley-Rice irregular terrain model and digital elevation data representative of an analogue lunar site for the prediction of RF path loss over the lunar surface. The results are validated by theoretical models and past Apollo studies. The model is used to approximate the path loss deviation from theoretical attenuation over a reflecting sphere. Analysis of the simulation results provides statistics on the fade depths for frequencies of interest, and correspondingly a method for determining the maximum range of communications for various coverage confidence intervals. Communication system engineers and mission planners are provided a link margin and path loss policy for communication frequencies of interest.

Analysis of explicit model predictive control for path-following control.

Science.gov (United States)

Lee, Junho; Chang, Hyuk-Jun

2018-01-01

In this paper, explicit Model Predictive Control(MPC) is employed for automated lane-keeping systems. MPC has been regarded as the key to handle such constrained systems. However, the massive computational complexity of MPC, which employs online optimization, has been a major drawback that limits the range of its target application to relatively small and/or slow problems. Explicit MPC can reduce this computational burden using a multi-parametric quadratic programming technique(mp-QP). The control objective is to derive an optimal front steering wheel angle at each sampling time so that autonomous vehicles travel along desired paths, including straight, circular, and clothoid parts, at high entry speeds. In terms of the design of the proposed controller, a method of choosing weighting matrices in an optimization problem and the range of horizons for path-following control are described through simulations. For the verification of the proposed controller, simulation results obtained using other control methods such as MPC, Linear-Quadratic Regulator(LQR), and driver model are employed, and CarSim, which reflects the features of a vehicle more realistically than MATLAB/Simulink, is used for reliable demonstration.

Analysis of explicit model predictive control for path-following control

Science.gov (United States)

2018-01-01

In this paper, explicit Model Predictive Control(MPC) is employed for automated lane-keeping systems. MPC has been regarded as the key to handle such constrained systems. However, the massive computational complexity of MPC, which employs online optimization, has been a major drawback that limits the range of its target application to relatively small and/or slow problems. Explicit MPC can reduce this computational burden using a multi-parametric quadratic programming technique(mp-QP). The control objective is to derive an optimal front steering wheel angle at each sampling time so that autonomous vehicles travel along desired paths, including straight, circular, and clothoid parts, at high entry speeds. In terms of the design of the proposed controller, a method of choosing weighting matrices in an optimization problem and the range of horizons for path-following control are described through simulations. For the verification of the proposed controller, simulation results obtained using other control methods such as MPC, Linear-Quadratic Regulator(LQR), and driver model are employed, and CarSim, which reflects the features of a vehicle more realistically than MATLAB/Simulink, is used for reliable demonstration. PMID:29534080

Consistent mutational paths predict eukaryotic thermostability

Directory of Open Access Journals (Sweden)

van Noort Vera

2013-01-01

Full Text Available Abstract Background Proteomes of thermophilic prokaryotes have been instrumental in structural biology and successfully exploited in biotechnology, however many proteins required for eukaryotic cell function are absent from bacteria or archaea. With Chaetomium thermophilum, Thielavia terrestris and Thielavia heterothallica three genome sequences of thermophilic eukaryotes have been published. Results Studying the genomes and proteomes of these thermophilic fungi, we found common strategies of thermal adaptation across the different kingdoms of Life, including amino acid biases and a reduced genome size. A phylogenetics-guided comparison of thermophilic proteomes with those of other, mesophilic Sordariomycetes revealed consistent amino acid substitutions associated to thermophily that were also present in an independent lineage of thermophilic fungi. The most consistent pattern is the substitution of lysine by arginine, which we could find in almost all lineages but has not been extensively used in protein stability engineering. By exploiting mutational paths towards the thermophiles, we could predict particular amino acid residues in individual proteins that contribute to thermostability and validated some of them experimentally. By determining the three-dimensional structure of an exemplar protein from C. thermophilum (Arx1, we could also characterise the molecular consequences of some of these mutations. Conclusions The comparative analysis of these three genomes not only enhances our understanding of the evolution of thermophily, but also provides new ways to engineer protein stability.

Predicting the distribution of spiral waves from cell properties in a developmental-path model of Dictyostelium pattern formation.

Directory of Open Access Journals (Sweden)

Daniel Geberth

2009-07-01

Full Text Available The slime mold Dictyostelium discoideum is one of the model systems of biological pattern formation. One of the most successful answers to the challenge of establishing a spiral wave pattern in a colony of homogeneously distributed D. discoideum cells has been the suggestion of a developmental path the cells follow (Lauzeral and coworkers. This is a well-defined change in properties each cell undergoes on a longer time scale than the typical dynamics of the cell. Here we show that this concept leads to an inhomogeneous and systematic spatial distribution of spiral waves, which can be predicted from the distribution of cells on the developmental path. We propose specific experiments for checking whether such systematics are also found in data and thus, indirectly, provide evidence of a developmental path.

Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

Science.gov (United States)

Wutich, A.; White, A. C.; White, D. D.; Larson, K. L.; Brewis, A.; Roberts, C.

2014-01-01

In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences associated with development status and, to a lesser extent, water scarcity. People in the two less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in the more developed sites. Thematically, people in the two less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community-based solutions, while people in the more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in the two water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in the water-rich sites. Thematically, people in the two water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in the water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

Self-controlled learning benefits: exploring contributions of self-efficacy and intrinsic motivation via path analysis.

Science.gov (United States)

Ste-Marie, Diane M; Carter, Michael J; Law, Barbi; Vertes, Kelly; Smith, Victoria

2016-09-01

Research has shown learning advantages for self-controlled practice contexts relative to yoked (i.e., experimenter-imposed) contexts; yet, explanations for this phenomenon remain relatively untested. We examined, via path analysis, whether self-efficacy and intrinsic motivation are important constructs for explaining self-controlled learning benefits. The path model was created using theory-based and empirically supported relationships to examine causal links between these psychological constructs and physical performance. We hypothesised that self-efficacy and intrinsic motivation would have greater predictive power for learning under self-controlled compared to yoked conditions. Participants learned double-mini trampoline progressions, and measures of physical performance, self-efficacy and intrinsic motivation were collected over two practice days and a delayed retention day. The self-controlled group (M = 2.04, SD = .98) completed significantly more skill progressions in retention than their yoked counterparts (M = 1.3, SD = .65). The path model displayed adequate fit, and similar significant path coefficients were found for both groups wherein each variable was predominantly predicted by its preceding time point (e.g., self-efficacy time 1 predicts self-efficacy time 2). Interestingly, the model was not moderated by group; thus, failing to support the hypothesis that self-efficacy and intrinsic motivation have greater predictive power for learning under self-controlled relative to yoked conditions.

prediction of path loss estimate for a frequency modulation (fm)

African Journals Online (AJOL)

Orinya

Nigeria, FM station, Makurdi which is normally a major component in the ... and can be used to estimate path losses of FM signals in Benue State of ... limited in equipment to measure all the .... path loss while MATLAB R2007b software was.

Path tortuosity in everyday movements of elderly persons increases fall prediction beyond knowledge of fall history, medication use, and standardized gait and balance assessments.

Science.gov (United States)

Kearns, William D; Fozard, James L; Becker, Marion; Jasiewicz, Jan M; Craighead, Jeffrey D; Holtsclaw, Lori; Dion, Charles

2012-09-01

We hypothesized that variability in voluntary movement paths of assisted living facility (ALF) residents would be greater in the week preceding a fall compared with residents who did not fall. Prospective, observational study using telesurveillance technology. Two ALFs. The sample consisted of 69 older ALF residents (53 female) aged 76.9 (SD ± 11.9 years). Daytime movement in ALF common use areas was automatically tracked using a commercially available ultra-wideband radio real-time location sensor network with a spatial resolution of approximately 20 cm. Movement path variability (tortuosity) was gauged using fractal dimension (fractal D). A logistic regression was performed predicting movement related falls from fractal D, presence of a fall in the prior year, psychoactive medication use, and movement path length. Fallers and non-fallers were also compared on activities of daily living requiring supervision or assistance, performance on standardized static and dynamic balance, and stride velocity assessments gathered at the start of a 1-year fall observation period. Fall risk due to cognitive deficit was assessed by the Mini Mental Status Examination (MMSE), and by clinical dementia diagnoses from participant's activities of daily living health record. Logistic regression analysis revealed odds of falling increased 2.548 (P = .021) for every 0.1 increase in fractal D, and having a fall in the prior year increased odds of falling by 7.36 (P = .006). There was a trend for longer movement paths to reduce the odds of falling (OR .976 P = .08) but it was not significant. Number of psychoactive medications did not contribute significantly to fall prediction in the model. Fallers had more variable stride-to-stride velocities and required more activities of daily living assistance. High fractal D levels can be detected using commercially available telesurveillance technologies and offers a new tool for health services administrators seeking to reduce falls at their

Spreading paths in partially observed social networks

Science.gov (United States)

Onnela, Jukka-Pekka; Christakis, Nicholas A.

2012-03-01

Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using static, structurally realistic social networks as platforms for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Although partial observation inflates the length of the shortest path, the stochastic nature of the spreading process also frequently derails the dynamic path from the shortest path. We find that the partially observed shortest path does not necessarily give an inflated estimate of the length of the process path; in fact, partial observation may, counterintuitively, make the path seem shorter than it actually is.

Spreading paths in partially observed social networks.

Science.gov (United States)

Onnela, Jukka-Pekka; Christakis, Nicholas A

2012-03-01

Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using static, structurally realistic social networks as platforms for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Although partial observation inflates the length of the shortest path, the stochastic nature of the spreading process also frequently derails the dynamic path from the shortest path. We find that the partially observed shortest path does not necessarily give an inflated estimate of the length of the process path; in fact, partial observation may, counterintuitively, make the path seem shorter than it actually is.

Airborne sound insulation evaluation and flanking path prediction of coupled room

Science.gov (United States)

Tassia, R. D.; Asmoro, W. A.; Arifianto, D.

2016-11-01

One of the parameters to review the acoustic comfort is based on the value of the insulation partition in the classroom. The insulation value can be expressed by the sound transmission loss which converted into a single value as weighted sound reduction index (Rw, DnTw) and also have an additional sound correction factor in low frequency (C, Ctr) .In this study, the measurements were performed in two positions at each point using BSWA microphone and dodecahedron speaker as the sound source. The results of field measurements indicate the acoustic insulation values (DnT w + C) is 19.6 dB. It is noted that the partition wall not according to the standard which the DnTw + C> 51 dB. Hence the partition wall need to be redesign to improve acoustic insulation in the classroom. The design used gypsum board, plasterboard, cement board, and PVC as the replacement material. Based on the results, all the material is simulated in accordance with established standards. Best insulation is cement board with the insulation value is 69dB, the thickness of 12.5 mm on each side and the absorber material is 50 mm. Many factors lead to increase the value of acoustic insulation, such as the thickness of the panel, the addition of absorber material, density, and Poisson's ratio of a material. The prediction of flanking path can be estimated from noise reduction values at each measurement point in the class room. Based on data obtained, there is no significant change in noise reduction from each point so that the pathway of flanking is not affect the sound transmission in the classroom.

comparative analysis of path loss prediction models for urban

African Journals Online (AJOL)

the acceptable minimum MSE value of 6dB for good signal propagation. Keywords: macrocellular areas ... itate high-speed data communications in ad- dition to voice calls. ... On the basis of the mobile radio environment, path loss predic-.

Epidemic extinction paths in complex networks

Science.gov (United States)

Hindes, Jason; Schwartz, Ira B.

2017-05-01

We study the extinction of long-lived epidemics on finite complex networks induced by intrinsic noise. Applying analytical techniques to the stochastic susceptible-infected-susceptible model, we predict the distribution of large fluctuations, the most probable or optimal path through a network that leads to a disease-free state from an endemic state, and the average extinction time in general configurations. Our predictions agree with Monte Carlo simulations on several networks, including synthetic weighted and degree-distributed networks with degree correlations, and an empirical high school contact network. In addition, our approach quantifies characteristic scaling patterns for the optimal path and distribution of large fluctuations, both near and away from the epidemic threshold, in networks with heterogeneous eigenvector centrality and degree distributions.

Strain path dependency in metal plasticity

NARCIS (Netherlands)

Viatkina, E.M.; Brekelmans, W.A.M.; Geers, M.G.D.

2003-01-01

A change in strain path has a significant effect on the mechanical response of metals. Strain path change effects physically originate from a complex microstructure evolution. This paper deals with the contribution of cell structure evolution to the strain path change effect. The material with cells

Design of a Path-Tracking Steering Controller for Autonomous Vehicles

Directory of Open Access Journals (Sweden)

Chuanyang Sun

2018-06-01

Full Text Available This paper presents a linearization method for the vehicle and tire models under the model predictive control (MPC scheme, and proposes a linear model-based MPC path-tracking steering controller for autonomous vehicles. The steering controller is designed to minimize lateral path-tracking deviation at high speeds. The vehicle model is linearized by a sequence of supposed steering angles, which are obtained by assuming the vehicle can reach the desired path at the end of the MPC prediction horizon and stay in a steady-state condition. The lateral force of the front tire is directly used as the control input of the model, and the rear tire’s lateral force is linearized by an equivalent cornering stiffness. The course-direction deviation, which is the angle between the velocity vector and the path heading, is chosen as a control reference state. The linearization model is validated through the simulation, and the results show high prediction accuracy even in regions of large steering angle. This steering controller is tested through simulations on the CarSim-Simulink platform (R2013b, MathWorks, Natick, MA, USA, showing the improved performance of the present controller at high speeds.

MinePath: Mining for Phenotype Differential Sub-paths in Molecular Pathways

Science.gov (United States)

Koumakis, Lefteris; Kartsaki, Evgenia; Chatzimina, Maria; Zervakis, Michalis; Vassou, Despoina; Marias, Kostas; Moustakis, Vassilis; Potamias, George

2016-01-01

Pathway analysis methodologies couple traditional gene expression analysis with knowledge encoded in established molecular pathway networks, offering a promising approach towards the biological interpretation of phenotype differentiating genes. Early pathway analysis methodologies, named as gene set analysis (GSA), view pathways just as plain lists of genes without taking into account either the underlying pathway network topology or the involved gene regulatory relations. These approaches, even if they achieve computational efficiency and simplicity, consider pathways that involve the same genes as equivalent in terms of their gene enrichment characteristics. Most recent pathway analysis approaches take into account the underlying gene regulatory relations by examining their consistency with gene expression profiles and computing a score for each profile. Even with this approach, assessing and scoring single-relations limits the ability to reveal key gene regulation mechanisms hidden in longer pathway sub-paths. We introduce MinePath, a pathway analysis methodology that addresses and overcomes the aforementioned problems. MinePath facilitates the decomposition of pathways into their constituent sub-paths. Decomposition leads to the transformation of single-relations to complex regulation sub-paths. Regulation sub-paths are then matched with gene expression sample profiles in order to evaluate their functional status and to assess phenotype differential power. Assessment of differential power supports the identification of the most discriminant profiles. In addition, MinePath assess the significance of the pathways as a whole, ranking them by their p-values. Comparison results with state-of-the-art pathway analysis systems are indicative for the soundness and reliability of the MinePath approach. In contrast with many pathway analysis tools, MinePath is a web-based system (www.minepath.org) offering dynamic and rich pathway visualization functionality, with the

Welding Robot Collision-Free Path Optimization

Directory of Open Access Journals (Sweden)

Xuewu Wang

2017-02-01

Full Text Available Reasonable welding path has a significant impact on welding efficiency, and a collision-free path should be considered first in the process of welding robot path planning. The shortest path length is considered as an optimization objective, and obstacle avoidance is considered as the constraint condition in this paper. First, a grid method is used as a modeling method after the optimization objective is analyzed. For local collision-free path planning, an ant colony algorithm is selected as the search strategy. Then, to overcome the shortcomings of the ant colony algorithm, a secondary optimization is presented to improve the optimization performance. Finally, the particle swarm optimization algorithm is used to realize global path planning. Simulation results show that the desired welding path can be obtained based on the optimization strategy.

Shortest-path network analysis is a useful approach toward identifying genetic determinants of longevity.

Directory of Open Access Journals (Sweden)

J R Managbanag

Full Text Available BACKGROUND: Identification of genes that modulate longevity is a major focus of aging-related research and an area of intense public interest. In addition to facilitating an improved understanding of the basic mechanisms of aging, such genes represent potential targets for therapeutic intervention in multiple age-associated diseases, including cancer, heart disease, diabetes, and neurodegenerative disorders. To date, however, targeted efforts at identifying longevity-associated genes have been limited by a lack of predictive power, and useful algorithms for candidate gene-identification have also been lacking. METHODOLOGY/PRINCIPAL FINDINGS: We have utilized a shortest-path network analysis to identify novel genes that modulate longevity in Saccharomyces cerevisiae. Based on a set of previously reported genes associated with increased life span, we applied a shortest-path network algorithm to a pre-existing protein-protein interaction dataset in order to construct a shortest-path longevity network. To validate this network, the replicative aging potential of 88 single-gene deletion strains corresponding to predicted components of the shortest-path longevity network was determined. Here we report that the single-gene deletion strains identified by our shortest-path longevity analysis are significantly enriched for mutations conferring either increased or decreased replicative life span, relative to a randomly selected set of 564 single-gene deletion strains or to the current data set available for the entire haploid deletion collection. Further, we report the identification of previously unknown longevity genes, several of which function in a conserved longevity pathway believed to mediate life span extension in response to dietary restriction. CONCLUSIONS/SIGNIFICANCE: This work demonstrates that shortest-path network analysis is a useful approach toward identifying genetic determinants of longevity and represents the first application of

Morphological Awareness in Literacy Acquisition of Chinese Second Graders: A Path Analysis.

Science.gov (United States)

Zhang, Haomin

2016-02-01

The present study tested a path diagram regarding the contribution of morphological awareness (MA) to early literacy acquisition among Chinese-speaking second graders ([Formula: see text]). Three facets of MA were addressed, namely derivational awareness, compound awareness and compound structure awareness. The model aimed to test a theory of causal order among measures of MA and literacy outcomes. Drawing upon multivariate path analysis, direct and indirect effects of MA were analyzed to identify their role in literacy performance among young children. Results revealed that all three facets of MA made significant contributions to lexical inference ability. In addition, compound awareness showed a unique and significant contribution to vocabulary knowledge. It was also observed that lexical inference ability had a mediating effect predictive of both vocabulary knowledge and reading comprehension. Moreover, vocabulary knowledge mediated the effect of MA on reading comprehension. However, no significant contribution of MA to reading comprehension was found after controlling for lexical inference ability and vocabulary knowledge.

Optimal Paths in Gliding Flight

Science.gov (United States)

Wolek, Artur

Underwater gliders are robust and long endurance ocean sampling platforms that are increasingly being deployed in coastal regions. This new environment is characterized by shallow waters and significant currents that can challenge the mobility of these efficient (but traditionally slow moving) vehicles. This dissertation aims to improve the performance of shallow water underwater gliders through path planning. The path planning problem is formulated for a dynamic particle (or "kinematic car") model. The objective is to identify the path which satisfies specified boundary conditions and minimizes a particular cost. Several cost functions are considered. The problem is addressed using optimal control theory. The length scales of interest for path planning are within a few turn radii. First, an approach is developed for planning minimum-time paths, for a fixed speed glider, that are sub-optimal but are guaranteed to be feasible in the presence of unknown time-varying currents. Next the minimum-time problem for a glider with speed controls, that may vary between the stall speed and the maximum speed, is solved. Last, optimal paths that minimize change in depth (equivalently, maximize range) are investigated. Recognizing that path planning alone cannot overcome all of the challenges associated with significant currents and shallow waters, the design of a novel underwater glider with improved capabilities is explored. A glider with a pneumatic buoyancy engine (allowing large, rapid buoyancy changes) and a cylindrical moving mass mechanism (generating large pitch and roll moments) is designed, manufactured, and tested to demonstrate potential improvements in speed and maneuverability.

Path coupling and aggregate path coupling

CERN Document Server

Kovchegov, Yevgeniy

2018-01-01

This book describes and characterizes an extension to the classical path coupling method applied to statistical mechanical models, referred to as aggregate path coupling. In conjunction with large deviations estimates, the aggregate path coupling method is used to prove rapid mixing of Glauber dynamics for a large class of statistical mechanical models, including models that exhibit discontinuous phase transitions which have traditionally been more difficult to analyze rigorously. The book shows how the parameter regions for rapid mixing for several classes of statistical mechanical models are derived using the aggregate path coupling method.

Path Creation, Path Dependence and Breaking Away from the Path

OpenAIRE

Wang, Jens; Hedman, Jonas; Tuunainen, Virpi Kristiina

2016-01-01

The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop and extend a multi-layer path dependence framework. We identify four layers of path dependence: technical, strategic and leadership, organizational, and external collaboration. We show how path dep...

A link prediction method for heterogeneous networks based on BP neural network

Science.gov (United States)

Li, Ji-chao; Zhao, Dan-ling; Ge, Bing-Feng; Yang, Ke-Wei; Chen, Ying-Wu

2018-04-01

Most real-world systems, composed of different types of objects connected via many interconnections, can be abstracted as various complex heterogeneous networks. Link prediction for heterogeneous networks is of great significance for mining missing links and reconfiguring networks according to observed information, with considerable applications in, for example, friend and location recommendations and disease-gene candidate detection. In this paper, we put forward a novel integrated framework, called MPBP (Meta-Path feature-based BP neural network model), to predict multiple types of links for heterogeneous networks. More specifically, the concept of meta-path is introduced, followed by the extraction of meta-path features for heterogeneous networks. Next, based on the extracted meta-path features, a supervised link prediction model is built with a three-layer BP neural network. Then, the solution algorithm of the proposed link prediction model is put forward to obtain predicted results by iteratively training the network. Last, numerical experiments on the dataset of examples of a gene-disease network and a combat network are conducted to verify the effectiveness and feasibility of the proposed MPBP. It shows that the MPBP with very good performance is superior to the baseline methods.

Path-integral method for the source apportionment of photochemical pollutants

Science.gov (United States)

Dunker, A. M.

2015-06-01

A new, path-integral method is presented for apportioning the concentrations of pollutants predicted by a photochemical model to emissions from different sources. A novel feature of the method is that it can apportion the difference in a species concentration between two simulations. For example, the anthropogenic ozone increment, which is the difference between a simulation with all emissions present and another simulation with only the background (e.g., biogenic) emissions included, can be allocated to the anthropogenic emission sources. The method is based on an existing, exact mathematical equation. This equation is applied to relate the concentration difference between simulations to line or path integrals of first-order sensitivity coefficients. The sensitivities describe the effects of changing the emissions and are accurately calculated by the decoupled direct method. The path represents a continuous variation of emissions between the two simulations, and each path can be viewed as a separate emission-control strategy. The method does not require auxiliary assumptions, e.g., whether ozone formation is limited by the availability of volatile organic compounds (VOCs) or nitrogen oxides (NOx), and can be used for all the species predicted by the model. A simplified configuration of the Comprehensive Air Quality Model with Extensions (CAMx) is used to evaluate the accuracy of different numerical integration procedures and the dependence of the source contributions on the path. A Gauss-Legendre formula using three or four points along the path gives good accuracy for apportioning the anthropogenic increments of ozone, nitrogen dioxide, formaldehyde, and nitric acid. Source contributions to these increments were obtained for paths representing proportional control of all anthropogenic emissions together, control of NOx emissions before VOC emissions, and control of VOC emissions before NOx emissions. There are similarities in the source contributions from the

Safe Maritime Autonomous Path Planning in a High Sea State

Science.gov (United States)

Ono, Masahiro; Quadrelli, Marco; Huntsberger, Terrance L.

2014-01-01

This paper presents a path planning method for sea surface vehicles that prevents capsizing and bow-diving in a high sea-state. A key idea is to use response amplitude operators (RAOs) or, in control terminology, the transfer functions from a sea state to a vessel's motion, in order to find a set of speeds and headings that results in excessive pitch and roll oscillations. This information is translated to arithmetic constraints on the ship's velocity, which are passed to a model predictive control (MPC)-based path planner to find a safe and optimal path that achieves specified goals. An obstacle avoidance capability is also added to the path planner. The proposed method is demonstrated by simulations.

RNAspa: a shortest path approach for comparative prediction of the secondary structure of ncRNA molecules

Directory of Open Access Journals (Sweden)

Michaeli Shulamit

2007-10-01

Full Text Available Abstract Background In recent years, RNA molecules that are not translated into proteins (ncRNAs have drawn a great deal of attention, as they were shown to be involved in many cellular functions. One of the most important computational problems regarding ncRNA is to predict the secondary structure of a molecule from its sequence. In particular, we attempted to predict the secondary structure for a set of unaligned ncRNA molecules that are taken from the same family, and thus presumably have a similar structure. Results We developed the RNAspa program, which comparatively predicts the secondary structure for a set of ncRNA molecules in linear time in the number of molecules. We observed that in a list of several hundred suboptimal minimal free energy (MFE predictions, as provided by the RNAsubopt program of the Vienna package, it is likely that at least one suggested structure would be similar to the true, correct one. The suboptimal solutions of each molecule are represented as a layer of vertices in a graph. The shortest path in this graph is the basis for structural predictions for the molecule. We also show that RNA secondary structures can be compared very rapidly by a simple string Edit-Distance algorithm with a minimal loss of accuracy. We show that this approach allows us to more deeply explore the suboptimal structure space. Conclusion The algorithm was tested on three datasets which include several ncRNA families taken from the Rfam database. These datasets allowed for comparison of the algorithm with other methods. In these tests, RNAspa performed better than four other programs.

Gibbon travel paths are goal oriented.

Science.gov (United States)

Asensio, Norberto; Brockelman, Warren Y; Malaivijitnond, Suchinda; Reichard, Ulrich H

2011-05-01

Remembering locations of food resources is critical for animal survival. Gibbons are territorial primates which regularly travel through small and stable home ranges in search of preferred, limited and patchily distributed resources (primarily ripe fruit). They are predicted to profit from an ability to memorize the spatial characteristics of their home range and may increase their foraging efficiency by using a 'cognitive map' either with Euclidean or with topological properties. We collected ranging and feeding data from 11 gibbon groups (Hylobates lar) to test their navigation skills and to better understand gibbons' 'spatial intelligence'. We calculated the locations at which significant travel direction changes occurred using the change-point direction test and found that these locations primarily coincided with preferred fruit sources. Within the limits of biologically realistic visibility distances observed, gibbon travel paths were more efficient in detecting known preferred food sources than a heuristic travel model based on straight travel paths in random directions. Because consecutive travel change-points were far from the gibbons' sight, planned movement between preferred food sources was the most parsimonious explanation for the observed travel patterns. Gibbon travel appears to connect preferred food sources as expected under the assumption of a good mental representation of the most relevant sources in a large-scale space.

Reaction path of energetic materials using THOR code

Science.gov (United States)

Durães, L.; Campos, J.; Portugal, A.

1998-07-01

The method of predicting reaction path, using THOR code, allows for isobar and isochor adiabatic combustion and CJ detonation regimes, the calculation of the composition and thermodynamic properties of reaction products of energetic materials. THOR code assumes the thermodynamic equilibria of all possible products, for the minimum Gibbs free energy, using HL EoS. The code allows the possibility of estimating various sets of reaction products, obtained successively by the decomposition of the original reacting compound, as a function of the released energy. Two case studies of thermal decomposition procedure were selected, calculated and discussed—pure Ammonium Nitrate and its based explosive ANFO, and Nitromethane—because their equivalence ratio is respectively lower, near and greater than the stoicheiometry. Predictions of reaction path are in good correlation with experimental values, proving the validity of proposed method.

Path Dependency

OpenAIRE

Mark Setterfield

2015-01-01

Path dependency is defined, and three different specific concepts of path dependency – cumulative causation, lock in, and hysteresis – are analyzed. The relationships between path dependency and equilibrium, and path dependency and fundamental uncertainty are also discussed. Finally, a typology of dynamical systems is developed to clarify these relationships.

Comparative Investigation on Tool Wear during End Milling of AISI H13 Steel with Different Tool Path Strategies

Science.gov (United States)

Adesta, Erry Yulian T.; Riza, Muhammad; Avicena

2018-03-01

Tool wear prediction plays a significant role in machining industry for proper planning and control machining parameters and optimization of cutting conditions. This paper aims to investigate the effect of tool path strategies that are contour-in and zigzag tool path strategies applied on tool wear during pocket milling process. The experiments were carried out on CNC vertical machining centre by involving PVD coated carbide inserts. Cutting speed, feed rate and depth of cut were set to vary. In an experiment with three factors at three levels, Response Surface Method (RSM) design of experiment with a standard called Central Composite Design (CCD) was employed. Results obtained indicate that tool wear increases significantly at higher range of feed per tooth compared to cutting speed and depth of cut. This result of this experimental work is then proven statistically by developing empirical model. The prediction model for the response variable of tool wear for contour-in strategy developed in this research shows a good agreement with experimental work.

The contribution of personality and workplace characteristics in predicting turnover intention among sexual assault nurse examiners: a path analytic study.

Science.gov (United States)

Strunk, Kathleen C; Strunk, Kamden K

2012-09-01

The purpose of this study was to determine how personality characteristics, sense of organizational empowerment, and job satisfaction combine to predict turnover intention among a population of Sexual Assault Nurse Examiners (SANEs). Data were collected from 161 SANEs from 23 SANE organizations across the central and west United States through standardized tools and a demographic questionnaire. Both personality, namely agreeableness and workplace characteristics, particularly perceived empowerment and job satisfaction, combine to predict intention to leave the job of these sampled SANEs. One particularly curious finding was the positive prediction of agreeableness on turnover intention - that is, more agreeable people would be more likely to leave their jobs as SANEs. Professionals can gain insight from the path analysis results that show the need to address both personal and organizational factors in mitigating turnover intention among SANEs. This appears to be particularly true in providing a sense of empowerment and opportunity within the organization. © 2012 International Association of Forensic Nurses.

Quivers of Bound Path Algebras and Bound Path Coalgebras

Directory of Open Access Journals (Sweden)

Dr. Intan Muchtadi

2010-09-01

Full Text Available bras and coalgebras can be represented as quiver (directed graph, and from quiver we can construct algebras and coalgebras called path algebras and path coalgebras. In this paper we show that the quiver of a bound path coalgebra (resp. algebra is the dual quiver of its bound path algebra (resp. coalgebra.

Fractional path planning and path tracking

International Nuclear Information System (INIS)

Melchior, P.; Jallouli-Khlif, R.; Metoui, B.

2011-01-01

This paper presents the main results of the application of fractional approach in path planning and path tracking. A new robust path planning design for mobile robot was studied in dynamic environment. The normalized attractive force applied to the robot is based on a fictitious fractional attractive potential. This method allows to obtain robust path planning despite robot mass variation. The danger level of each obstacles is characterized by the fractional order of the repulsive potential of the obstacles. Under these conditions, the robot dynamic behavior was studied by analyzing its X - Y path planning with dynamic target or dynamic obstacles. The case of simultaneously mobile obstacles and target is also considered. The influence of the robot mass variation is studied and the robustness analysis of the obtained path shows the robustness improvement due to the non integer order properties. Pre shaping approach is used to reduce system vibration in motion control. Desired systems inputs are altered so that the system finishes the requested move without residual vibration. This technique, developed by N.C. Singer and W.P.Seering, is used for flexible structure control, particularly in the aerospace field. In a previous work, this method was extended for explicit fractional derivative systems and applied to second generation CRONE control, the robustness was also studied. CRONE (the French acronym of C ommande Robuste d'Ordre Non Entier ) control system design is a frequency-domain based methodology using complex fractional integration.

Path spectra derived from inversion of source and site spectra for earthquakes in Southern California

Science.gov (United States)

Klimasewski, A.; Sahakian, V. J.; Baltay, A.; Boatwright, J.; Fletcher, J. B.; Baker, L. M.

2017-12-01

A large source of epistemic uncertainty in Ground Motion Prediction Equations (GMPEs) is derived from the path term, currently represented as a simple geometric spreading and intrinsic attenuation term. Including additional physical relationships between the path properties and predicted ground motions would produce more accurate and precise, region-specific GMPEs by reclassifying some of the random, aleatory uncertainty as epistemic. This study focuses on regions of Southern California, using data from the Anza network and Southern California Seismic network to create a catalog of events magnitude 2.5 and larger from 1998 to 2016. The catalog encompasses regions of varying geology and therefore varying path and site attenuation. Within this catalog of events, we investigate several collections of event region-to-station pairs, each of which share similar origin locations and stations so that all events have similar paths. Compared with a simple regional GMPE, these paths consistently have high or low residuals. By working with events that have the same path, we can isolate source and site effects, and focus on the remaining residual as path effects. We decompose the recordings into source and site spectra for each unique event and site in our greater Southern California regional database using the inversion method of Andrews (1986). This model represents each natural log record spectra as the sum of its natural log event and site spectra, while constraining each record to a reference site or Brune source spectrum. We estimate a regional, path-specific anelastic attenuation (Q) and site attenuation (t*) from the inversion site spectra and corner frequency from the inversion event spectra. We then compute the residuals between the observed record data, and the inversion model prediction (event*site spectra). This residual is representative of path effects, likely anelastic attenuation along the path that varies from the regional median attenuation. We examine the

Bifurcation of transition paths induced by coupled bistable systems.

Science.gov (United States)

Tian, Chengzhe; Mitarai, Namiko

2016-06-07

We discuss the transition paths in a coupled bistable system consisting of interacting multiple identical bistable motifs. We propose a simple model of coupled bistable gene circuits as an example and show that its transition paths are bifurcating. We then derive a criterion to predict the bifurcation of transition paths in a generalized coupled bistable system. We confirm the validity of the theory for the example system by numerical simulation. We also demonstrate in the example system that, if the steady states of individual gene circuits are not changed by the coupling, the bifurcation pattern is not dependent on the number of gene circuits. We further show that the transition rate exponentially decreases with the number of gene circuits when the transition path does not bifurcate, while a bifurcation facilitates the transition by lowering the quasi-potential energy barrier.

Paths of Cultural Systems

Directory of Open Access Journals (Sweden)

Paul Ballonoff

2017-12-01

Full Text Available A theory of cultural structures predicts the objects observed by anthropologists. We here define those which use kinship relationships to define systems. A finite structure we call a partially defined quasigroup (or pdq, as stated by Definition 1 below on a dictionary (called a natural language allows prediction of certain anthropological descriptions, using homomorphisms of pdqs onto finite groups. A viable history (defined using pdqs states how an individual in a population following such history may perform culturally allowed associations, which allows a viable history to continue to survive. The vector states on sets of viable histories identify demographic observables on descent sequences. Paths of vector states on sets of viable histories may determine which histories can exist empirically.

High Altitude Balloon Flight Path Prediction and Site Selection Based On Computer Simulations

Science.gov (United States)

Linford, Joel

2010-10-01

Interested in the upper atmosphere, Weber State University Physics department has developed a High Altitude Reconnaissance Balloon for Outreach and Research team, also known as HARBOR. HARBOR enables Weber State University to take a variety of measurements from ground level to altitudes as high as 100,000 feet. The flight paths of these balloons can extend as long as 100 miles from the launch zone, making the choice of where and when to fly critical. To ensure the ability to recover the packages in a reasonable amount of time, days and times are carefully selected using computer simulations limiting flight tracks to approximately 40 miles from the launch zone. The computer simulations take atmospheric data collected by National Oceanic and Atmospheric Administration (NOAA) to plot what flights might have looked like in the past, and to predict future flights. Using these simulations a launch zone has been selected in Duchesne Utah, which has hosted eight successful flights over the course of the last three years, all of which have been recovered. Several secondary launch zones in western Wyoming, Southern Idaho, and Northern Utah are also being considered.

Two-dimensional velocity models for paths from Pahute Mesa and Yucca Flat to Yucca Mountain

International Nuclear Information System (INIS)

Walck, M.C.; Phillips, J.S.

1990-11-01

Vertical acceleration recordings of 21 underground nuclear explosions recorded at stations at Yucca Mountain provide the data for development of three two-dimensional crystal velocity profiles for portions of the Nevada Test Site. Paths from Area 19, Area 20 (both Pahute Mesa), and Yucca Flat to Yucca Mountain have been modeled using asymptotic ray theory travel time and synthetic seismogram techniques. Significant travel time differences exist between the Yucca Flat and Pahute Mesa source areas; relative amplitude patterns at Yucca Mountain also shift with changing source azimuth. The three models, UNEPM1, UNEPM2, and UNEYF1, successfully predict the travel time and amplitude data for all three paths. 24 refs., 34 figs., 8 tabs

[Dual insertion paths design characteristics and short-term clinical observation of rotational path removable partial dentures].

Science.gov (United States)

Li, Jian; Jiang, Ting; Li, Sai; Chen, Wei

2013-02-18

To investigate design methods of dual insertion paths and observe a short-term clinic overview of rotational path removable partial dentures (RPDs). In the study, 40 patients with partial edentulous arches were included and divided into two groups. The patients in group one were restored with rotational path RPDs (10 Kennedy class III and 10 Kennedy class IV respectively). The patients in group two (20 patients), whose edentulous area was matched with the patients' in group one, were restored with the linear path RPDs. After surveying and simulative preparation on diagnostic casts, the basic laws of designing rotational path RPDs were summarized. The oral preparation was accurately performed under the guidance of indices made on diagnostic casts after simulative preparation. The 40 dentures were recalled two weeks and one year after the insertion. The evaluations of the clinic outcome, including retention, stability, mastication function, esthetics and wearing convenience, were marked out as good, acceptable, and poor. The comparison of the evaluation results was performed between the two groups. In the rotational path design for Kennedy class III or IV RPDs, the angles (α) of dual insertion paths should be designed within a scope, approximate 10°-15°.When the angle (α) became larger, the denture retention turned to be better, but accordingly the posterior abutments needed more preparation. In the clinical application, the first insertions of the 40 dentures were all favorably accomplished. When the rotational path RPDs were compared to linear path RPDs, the time consuming on first insertion had no statistical difference[(32±8) min and (33±8) min respectively, P>0.05]. Recalled two weeks and one year after the insertion, in the esthetics evaluation, 20 rotational path RPDs were all evaluated as "A", but only 7(two weeks after) and 6 (one year after) linear path RPDs were evaluated as "A"(P<0.05). There was no significant difference in other evaluation results

Stress path dependent hydromechanical behaviour of heterogeneous carbonate rock

Directory of Open Access Journals (Sweden)

Dimanov A.

2010-06-01

Full Text Available The influence of stress paths, representative of reservoir conditions, on the hydromechanical behavior of a moderately heterogeneous carbonate has been investigated. Multiscale structural heterogeneities, common for instance in carbonate rocks, can strongly alter the mechanical response and significantly influence the evolution of flow properties with stress. Using a triaxial cell, the permeability evolutions during compression and the effects of brittle (fracture and plastic (pore collapse deformations at yield, were measured. A strong scattering was observed on the mechanical response both in term of compressibility and failure threshold. Using the porosity scaling predicted by an adapted effective medium theory (based on crack growth under Hertzian contact, we have rescaled the critical pressures by the normalized porosity deviation. This procedure reduces efficiently the scattering, revealing in the framework of proportional stress path loading, a linear relation between the critical pressures and the stress path parameter through all the deformation regimes. It leads to a new formulation for the critical state envelope in the 'mean stress, deviatoric stress' diagram. The attractive feature of this new yield envelope formulation relies on the fact that only the two most common different mechanical tests 'Uniaxial Compression' and 'Hydrostatic Compression', are needed to define entirely the yield envelope. Volumic strains and normalized permeabilities are finally mapped in the stresses diagram and correlated.

Formal language constrained path problems

Energy Technology Data Exchange (ETDEWEB)

Barrett, C.; Jacob, R.; Marathe, M.

1997-07-08

In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

Core self-evaluations and work engagement: Testing a perception, action, and development path.

Directory of Open Access Journals (Sweden)

Maria Tims

Full Text Available Core self-evaluations (CSE have predictive value for important work outcomes such as job satisfaction and job performance. However, little is known about the mechanisms that may explain these relationships. The purpose of the present study is to contribute to CSE theory by proposing and subsequently providing a first test of theoretically relevant mediating paths through which CSE may be related to work engagement. Based on approach/avoidance motivation and Job Demands-Resources theory, we examined a perception (via job characteristics, action (via job crafting, and development path (via career competencies. Two independent samples were obtained from employees working in Germany and The Netherlands (N = 303 and N = 404, respectively. When taking all mediators into account, results showed that the perception path represented by autonomy and social support played a minor role in the relationship between CSE and work engagement. Specifically, autonomy did not function as a mediator in both samples while social support played a marginally significant role in the CSE-work engagement relationship in sample 1 and received full support in sample 2. The action path exemplified by job crafting mediated the relationship between CSE and work engagement in both samples. Finally, the development path operationalized with career competencies mediated the relationship between CSE and work engagement in sample 1. The study presents evidence for an action and development path over and above the often tested perception path to explain how CSE is related to work engagement. This is one of the first studies to propose and show that CSE not only influences perceptions but also triggers employee actions and developmental strategies that relate to work engagement.

Core self-evaluations and work engagement: Testing a perception, action, and development path

Science.gov (United States)

Akkermans, Jos

2017-01-01

Core self-evaluations (CSE) have predictive value for important work outcomes such as job satisfaction and job performance. However, little is known about the mechanisms that may explain these relationships. The purpose of the present study is to contribute to CSE theory by proposing and subsequently providing a first test of theoretically relevant mediating paths through which CSE may be related to work engagement. Based on approach/avoidance motivation and Job Demands-Resources theory, we examined a perception (via job characteristics), action (via job crafting), and development path (via career competencies). Two independent samples were obtained from employees working in Germany and The Netherlands (N = 303 and N = 404, respectively). When taking all mediators into account, results showed that the perception path represented by autonomy and social support played a minor role in the relationship between CSE and work engagement. Specifically, autonomy did not function as a mediator in both samples while social support played a marginally significant role in the CSE–work engagement relationship in sample 1 and received full support in sample 2. The action path exemplified by job crafting mediated the relationship between CSE and work engagement in both samples. Finally, the development path operationalized with career competencies mediated the relationship between CSE and work engagement in sample 1. The study presents evidence for an action and development path over and above the often tested perception path to explain how CSE is related to work engagement. This is one of the first studies to propose and show that CSE not only influences perceptions but also triggers employee actions and developmental strategies that relate to work engagement. PMID:28787464

Core self-evaluations and work engagement: Testing a perception, action, and development path.

Science.gov (United States)

Tims, Maria; Akkermans, Jos

2017-01-01

Core self-evaluations (CSE) have predictive value for important work outcomes such as job satisfaction and job performance. However, little is known about the mechanisms that may explain these relationships. The purpose of the present study is to contribute to CSE theory by proposing and subsequently providing a first test of theoretically relevant mediating paths through which CSE may be related to work engagement. Based on approach/avoidance motivation and Job Demands-Resources theory, we examined a perception (via job characteristics), action (via job crafting), and development path (via career competencies). Two independent samples were obtained from employees working in Germany and The Netherlands (N = 303 and N = 404, respectively). When taking all mediators into account, results showed that the perception path represented by autonomy and social support played a minor role in the relationship between CSE and work engagement. Specifically, autonomy did not function as a mediator in both samples while social support played a marginally significant role in the CSE-work engagement relationship in sample 1 and received full support in sample 2. The action path exemplified by job crafting mediated the relationship between CSE and work engagement in both samples. Finally, the development path operationalized with career competencies mediated the relationship between CSE and work engagement in sample 1. The study presents evidence for an action and development path over and above the often tested perception path to explain how CSE is related to work engagement. This is one of the first studies to propose and show that CSE not only influences perceptions but also triggers employee actions and developmental strategies that relate to work engagement.

Analysing playing using the note-time playing path.

Science.gov (United States)

de Graaff, Deborah L E; Schubert, Emery

2011-03-01

This article introduces a new method of data analysis that represents the playing of written music as a graph. The method, inspired by Miklaszewski, charts low-level note timings from a sound recording of a single-line instrument using high-precision audio-to-MIDI conversion software. Note onset times of pitch sequences are then plotted against the score-predicted timings to produce a Note-Time Playing Path (NTPP). The score-predicted onset time of each sequentially performed note (horizontal axis) unfolds in performed time down the page (vertical axis). NTPPs provide a visualisation that shows (1) tempo variations, (2) repetitive practice behaviours, (3) segmenting of material, (4) precise note time positions, and (5) time spent on playing or not playing. The NTPP can provide significant new insights into behaviour and cognition of music performance and may also be used to complement established traditional approaches such as think-alouds, interviews, and video coding.

Feynman's path integrals and Bohm's particle paths

International Nuclear Information System (INIS)

Tumulka, Roderich

2005-01-01

Both Bohmian mechanics, a version of quantum mechanics with trajectories, and Feynman's path integral formalism have something to do with particle paths in space and time. The question thus arises how the two ideas relate to each other. In short, the answer is, path integrals provide a re-formulation of Schroedinger's equation, which is half of the defining equations of Bohmian mechanics. I try to give a clear and concise description of the various aspects of the situation. (letters and comments)

Multi-Dimensional Path Queries

DEFF Research Database (Denmark)

Bækgaard, Lars

1998-01-01

to create nested path structures. We present an SQL-like query language that is based on path expressions and we show how to use it to express multi-dimensional path queries that are suited for advanced data analysis in decision support environments like data warehousing environments......We present the path-relationship model that supports multi-dimensional data modeling and querying. A path-relationship database is composed of sets of paths and sets of relationships. A path is a sequence of related elements (atoms, paths, and sets of paths). A relationship is a binary path...

Polygonal-path approximations on the path spaces of quantum-mechanical systems: properties of the polygonal paths

International Nuclear Information System (INIS)

Exner, P.; Kolerov, G.I.

1981-01-01

Properties of the subset of polygonal paths in the Hilbert space H of paths referring to a d-dimensional quantum-mechanical system are examined. Using the reproduction kernel technique we prove that each element of H is approximated by polygonal paths uniformly with respect to the ''norm'' of time-interval partitions. This result will be applied in the second part of the present paper to prove consistency of the uniform polygonal-path extension of the Feynman maps [ru

Learning to improve path planning performance

International Nuclear Information System (INIS)

Chen, Pang C.

1995-04-01

In robotics, path planning refers to finding a short. collision-free path from an initial robot configuration to a desired configuratioin. It has to be fast to support real-time task-level robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To remedy this situation, we present and analyze a learning algorithm that uses past experience to increase future performance. The algorithm relies on an existing path planner to provide solutions to difficult tasks. From these solutions, an evolving sparse network of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a speedup-learning framework in which a slow but capable planner may be improved both cost-wise and capability-wise by a faster but less capable planner coupled with experience. The basic algorithm is suitable for stationary environments, and can be extended to accommodate changing environments with on-demand experience repair and object-attached experience abstraction. To analyze the algorithm, we characterize the situations in which the adaptive planner is useful, provide quantitative bounds to predict its behavior, and confirm our theoretical results with experiments in path planning of manipulators. Our algorithm and analysis are sufficiently, general that they may also be applied to other planning domains in which experience is useful

A high performance magnetorheological valve with a meandering flow path

International Nuclear Information System (INIS)

Imaduddin, Fitrian; Amri Mazlan, Saiful; Azizi Abdul Rahman, Mohd; Zamzuri, Hairi; Ubaidillah; Ichwan, Burhanuddin

2014-01-01

The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment

Medial temporal lobe roles in human path integration.

Directory of Open Access Journals (Sweden)

Naohide Yamamoto

Full Text Available Path integration is a process in which observers derive their location by integrating self-motion signals along their locomotion trajectory. Although the medial temporal lobe (MTL is thought to take part in path integration, the scope of its role for path integration remains unclear. To address this issue, we administered a variety of tasks involving path integration and other related processes to a group of neurosurgical patients whose MTL was unilaterally resected as therapy for epilepsy. These patients were unimpaired relative to neurologically intact controls in many tasks that required integration of various kinds of sensory self-motion information. However, the same patients (especially those who had lesions in the right hemisphere walked farther than the controls when attempting to walk without vision to a previewed target. Importantly, this task was unique in our test battery in that it allowed participants to form a mental representation of the target location and anticipate their upcoming walking trajectory before they began moving. Thus, these results put forth a new idea that the role of MTL structures for human path integration may stem from their participation in predicting the consequences of one's locomotor actions. The strengths of this new theoretical viewpoint are discussed.

Testing earthquake prediction algorithms: Statistically significant advance prediction of the largest earthquakes in the Circum-Pacific, 1992-1997

Science.gov (United States)

Kossobokov, V.G.; Romashkova, L.L.; Keilis-Borok, V. I.; Healy, J.H.

1999-01-01

Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-time intermediate-term research prediction of the strongest earthquakes in the Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are missed in the second approximation of prediction. In 1992-1997, five earthquakes of magnitude 8 and above occurred in the test area: all of them were predicted by M8 and MSc identified correctly the locations of four of them. The space-time volume of the alarms is 36% and 18%, correspondingly, when estimated with a normalized product measure of empirical distribution of epicenters and uniform time. The statistical significance of the achieved results is beyond 99% both for M8 and MSc. For magnitude 7.5 + , 10 out of 19 earthquakes were predicted by M8 in 40% and five were predicted by M8-MSc in 13% of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the largest events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc in complete formal definitions were published before we started our experiment [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of seismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossobokov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermediate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquake prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available from the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H.K. (Eds.), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. ?? 1999 Elsevier

Energy consumption of ProTaper Next X1 after glide path with PathFiles and ProGlider.

Science.gov (United States)

Berutti, Elio; Alovisi, Mario; Pastorelli, Michele Angelo; Chiandussi, Giorgio; Scotti, Nicola; Pasqualini, Damiano

2014-12-01

Instrument failure caused by excessive torsional stress can be controlled by creating a manual or mechanical glide path. The ProGlider single-file system (Dentsply Maillefer, Ballaigues, Switzerland) was recently introduced to perform a mechanical glide path. This study was designed to compare the effect of a glide path performed with PathFiles (Dentsply Maillefer) and ProGlider on torque, time, and pecking motion required for ProTaper Next X1 (Dentsply Maillefer) to reach the full working length in simulated root canals. Forty Endo Training Blocks (Dentsply Maillefer) were used. Twenty were prepared with a mechanical glide path using PathFiles 1 and 2 (the PathFile group), and 20 were prepared with a mechanical glide path using a ProGlider single file (the ProGlider group). All samples were shaped with ProTaper Next X1 driven by an endodontic motor connected to a digital wattmeter. The required torque for root canal instrumentation was analyzed by evaluating the electrical power consumption of the endodontic engine. Electric power consumption (mW/h), elapsed time (seconds), and number of pecking motions required to reach the full working length with ProTaper Next X1 were calculated. Differences among groups were analyzed with the parametric Student t test for independent data (P < .05). Elapsed time and electric power consumption were significantly different between groups (P = .0001 for both). ProGlider appears to perform more efficiently than PathFiles in decreasing electric power consumption of ProTaper Next X1 to reach the full working length. This study confirmed the ability of ProGlider to reduce stress in ProTaper Next X1 during shaping through a glide path and preliminary middle and coronal preflaring. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Macrocell path loss prediction using artificial intelligence techniques

Science.gov (United States)

Usman, Abraham U.; Okereke, Okpo U.; Omizegba, Elijah E.

2014-04-01

The prediction of propagation loss is a practical non-linear function approximation problem which linear regression or auto-regression models are limited in their ability to handle. However, some computational Intelligence techniques such as artificial neural networks (ANNs) and adaptive neuro-fuzzy inference systems (ANFISs) have been shown to have great ability to handle non-linear function approximation and prediction problems. In this study, the multiple layer perceptron neural network (MLP-NN), radial basis function neural network (RBF-NN) and an ANFIS network were trained using actual signal strength measurement taken at certain suburban areas of Bauchi metropolis, Nigeria. The trained networks were then used to predict propagation losses at the stated areas under differing conditions. The predictions were compared with the prediction accuracy of the popular Hata model. It was observed that ANFIS model gave a better fit in all cases having higher R2 values in each case and on average is more robust than MLP and RBF models as it generalises better to a different data.

Path planning in uncertain flow fields using ensemble method

KAUST Repository

Wang, Tong; Le Maî tre, Olivier P.; Hoteit, Ibrahim; Knio, Omar

2016-01-01

, we predict the path that minimizes the travel time by solving a boundary value problem (BVP), based on the Pontryagin maximum principle. A family of backward-in-time trajectories starting at the end position is used to generate suitable initial values

Pulled Motzkin paths

International Nuclear Information System (INIS)

Janse van Rensburg, E J

2010-01-01

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) → f as f → ∞, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) → 2f as f → ∞, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Pulled Motzkin paths

Energy Technology Data Exchange (ETDEWEB)

Janse van Rensburg, E J, E-mail: rensburg@yorku.c [Department of Mathematics and Statistics, York University, Toronto, ON, M3J 1P3 (Canada)

2010-08-20

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) {yields} f as f {yields} {infinity}, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) {yields} 2f as f {yields} {infinity}, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Pulled Motzkin paths

Science.gov (United States)

Janse van Rensburg, E. J.

2010-08-01

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) → f as f → ∞, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) → 2f as f → ∞, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Exploring the significance of human mobility patterns in social link prediction

KAUST Repository

Alharbi, Basma Mohammed

2014-01-01

Link prediction is a fundamental task in social networks. Recently, emphasis has been placed on forecasting new social ties using user mobility patterns, e.g., investigating physical and semantic co-locations for new proximity measure. This paper explores the effect of in-depth mobility patterns. Specifically, we study individuals\\' movement behavior, and quantify mobility on the basis of trip frequency, travel purpose and transportation mode. Our hybrid link prediction model is composed of two modules. The first module extracts mobility patterns, including travel purpose and mode, from raw trajectory data. The second module employs the extracted patterns for link prediction. We evaluate our method on two real data sets, GeoLife [15] and Reality Mining [5]. Experimental results show that our hybrid model significantly improves the accuracy of social link prediction, when comparing to primary topology-based solutions. Copyright 2014 ACM.

Graph Regularized Meta-path Based Transductive Regression in Heterogeneous Information Network.

Science.gov (United States)

Wan, Mengting; Ouyang, Yunbo; Kaplan, Lance; Han, Jiawei

2015-01-01

A number of real-world networks are heterogeneous information networks, which are composed of different types of nodes and links. Numerical prediction in heterogeneous information networks is a challenging but significant area because network based information for unlabeled objects is usually limited to make precise estimations. In this paper, we consider a graph regularized meta-path based transductive regression model ( Grempt ), which combines the principal philosophies of typical graph-based transductive classification methods and transductive regression models designed for homogeneous networks. The computation of our method is time and space efficient and the precision of our model can be verified by numerical experiments.

Model for the Path Loss of In-room Reverberant Channels

DEFF Research Database (Denmark)

Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri

2011-01-01

A general path loss model for in-room radio channels is proposed. The model is based on experimental observations of the behavior of the delay power spectrum in closed rooms. In a given closed room, the early part of the spectrum observed at different positions typically consists of a dominant...... allows for the prediction of path loss, mean delay, and RMS delay spread versus distance. We use measurements to validate the proposed model and we observe good agreement of the model prediction for mean delay and RMS delay spread....... component (peak) that vanishes as the transmitter-receiver distance increases, while the late part decays versus distance according to the same exponential law regardless of this distance. These observations motivate the proposed model of the delay power spectrum with an early dominant component...

Macro and intergranular stress responses of austenitic stainless steel to 90° strain path changes

International Nuclear Information System (INIS)

Gonzalez, D.; Kelleher, J.F.; Quinta da Fonseca, J.; Withers, P.J.

2012-01-01

Highlights: ► We measure and model the macro and IG stresses of ASS to 90° strain path changes. ► The macro stress–strain curves show a clear Bauschinger effect on reloading. ► This is only partially captured by the model. ► The measured {h k l} families show an earlier microyield than predicted. ► This difference is more noticeable for a strain path with a higher reversibility. - Abstract: Strain path history can play a crucial role in sensitising/desensitising metals to various damage mechanisms and yet little work has been done to quantify and understand how intergranular strains change upon path changes, or their effect on the macroscopic behaviour. Here we have measured, by neutron diffraction, and modelled, by crystal plasticity finite elements, the stress–strain responses of 316L stainless steel over three different 90° strain path changes using an assembled microstructure of randomly oriented crystallites. The measurements show a clear Bauschinger effect on reloading that is only partially captured by the model. Further, measurements of the elastic response of different {h k l} grain families revealed an even earlier onset of yield for strain paths reloaded in compression while a strain path reloaded in tension showed good agreement with corresponding predictions. Finally, we propose that the study of strain path effects provides a more rigorous test of crystal plasticity models than conventional in situ diffraction studies of uniaxial loading.

Path Expressions

Science.gov (United States)

1975-06-01

Traditionally, synchronization of concurrent processes is coded in line by operations on semaphores or similar objects. Path expressions move the...discussion about a variety of synchronization primitives . An analysis of their relative power is found in [3]. Path expressions do not introduce yet...another synchronization primitive . A path expression relates to such primitives as a for- or while-statement of an ALGOL-like language relates to a JUMP

Strain path and work-hardening behavior of brass

International Nuclear Information System (INIS)

Sakharova, N.A.; Fernandes, J.V.; Vieira, M.F.

2009-01-01

Plastic straining in metal forming usually includes changes of strain path, which are frequently not taken into account in the analysis of forming processes. Moreover, strain path change can significantly affect the mechanical behavior and microstructural evolution of the material. For this reason, a combination of several simple loading test sequences is an effective way to investigate the dislocation microstructure of sheet metals under such forming conditions. Pure tension and rolling strain paths and rolling-tension strain path sequences were performed on brass sheets. A study of mechanical behavior and microstructural evolution during the simple and the complex strain paths was carried out, within a wide range of strain values. The appearance and development of deformation twinning was evident. It was shown that strain path change promotes the onset of premature twinning. The work-hardening behavior is discussed in terms of the twinning and dislocation microstructure evolution, as revealed by transmission electron microscopy

Zero-Slack, Noncritical Paths

Science.gov (United States)

Simons, Jacob V., Jr.

2017-01-01

The critical path method/program evaluation and review technique method of project scheduling is based on the importance of managing a project's critical path(s). Although a critical path is the longest path through a network, its location in large projects is facilitated by the computation of activity slack. However, logical fallacies in…

Time-optimal path planning in uncertain flow fields using ensemble method

KAUST Repository

Wang, Tong

2016-01-06

An ensemble-based approach is developed to conduct time-optimal path planning in unsteady ocean currents under uncertainty. We focus our attention on two-dimensional steady and unsteady uncertain flows, and adopt a sampling methodology that is well suited to operational forecasts, where a set deterministic predictions is used to model and quantify uncertainty in the predictions. In the operational setting, much about dynamics, topography and forcing of the ocean environment is uncertain, and as a result a single path produced by a model simulation has limited utility. To overcome this limitation, we rely on a finitesize ensemble of deterministic forecasts to quantify the impact of variability in the dynamics. The uncertainty of flow field is parametrized using a finite number of independent canonical random variables with known densities, and the ensemble is generated by sampling these variables. For each the resulting realizations of the uncertain current field, we predict the optimal path by solving a boundary value problem (BVP), based on the Pontryagin maximum principle. A family of backward-in-time trajectories starting at the end position is used to generate suitable initial values for the BVP solver. This allows us to examine and analyze the performance of sampling strategy, and develop insight into extensions dealing with regional or general circulation models. In particular, the ensemble method enables us to perform a statistical analysis of travel times, and consequently develop a path planning approach that accounts for these statistics. The proposed methodology is tested for a number of scenarios. We first validate our algorithms by reproducing simple canonical solutions, and then demonstrate our approach in more complex flow fields, including idealized, steady and unsteady double-gyre flows.

Predictive toxicology: the paths of the future

International Nuclear Information System (INIS)

Detilleux, Ph.; Vallier, L.; Legallais, C.; Leclerc, E.; Prot, J.M.; Choucha, L.; Baudoin, R.; Dufresne, M.; Gautier, A.; Carpentier, B.; Mansuy, D.; Pery, A.; Brochot, C.; Manivet, Ph.; Rabilloud, Th.; Spire, C.; Coumoul, X.; Junot, Ch.; Laprevote, O.; Le pape, A.; Le Guevel, R.; Tourneur, E.; Ben Mkaddem, S.; Chassin, C.; Aloulou, M.; Goujon, J.M.; Hertif, A.; Ouali, N.; Vimont, S.; Monteiro, R.; Rondeau, E.; Elbim, C.; Werts, C.; Vandewalle, A.; Ben Mkaddem, S.; Pedruzzi, E.; Coant, N.; Bens, M.; Cluzeaud, F.; Ogier-Denis, E.; Pongnimitprasert, N.; Babin-Chevaye, C.; Fay, M.; Bernard, M.; Dupuy, C.; Ei Benna, J.; Gougerot-Pocidale, M.A.; Braut-Boucher, F.; Pinton, Ph.; Lucioli, J.; Tsybulskyy, D.; Joly, B.; Laffitte, J.; Bourges-Abella, N.; Oswald, I.P.; Kolf-Clauw, M.; Pierre, St.; Bats, A.S.; Chevallier, A.; Bui, L.Ch.; Ambolet-Camoit, A.; Garlatti, M.; Aggerbeck, M.; Barouki, R.; Al Khansa, I.; Blanck, O.; Guillouzo, A.; Bars, R.; Rouas, C.; Bensoussan, H.; Suhard, D.; Tessier, C.; Grandcolas, L.; Pallardy, M.; Gueguen, Y.; Sparfel, L.; Pinel-Marie, M.L.; Boize, M.; Koscielny, S.; Desmots, S.; Pery, A.; Fardel, O.; Alvergnas, M.; Rouleau, A.; Lucchi, G.; Mantion, G.; Heyd, B.; Richert, L.; Ducoroy, P.; Martin, H.; Val, St.; Martinon, L.; Cachier, H.; Yahyaoui, A.; Marfaing, H.; Baeza-Squiban, A.; Martin-Chouly, C.; Bonvallet, M.; Morzadec, C.; Fardel, O.; Vernhet, L.; Baverel, G.; El Hage, M.; Nazaret, R.; Conjard-Duplany, A.; Ferrier, B.; Martin, G.; Legendre, A.; Desmots, S.; Lecomte, A.; Froment, P.; Habert, R.; Lemazurier, E.; Robinel, F.; Dupont, O.; Sanfins, E.; Dairou, J.; Chaffotte, A.F.; Busi, F.; Rodrigues Lima, F.; Dupret, J.M.; Mayati, A.; Le Ferrec, E.; Levoin, N.; Paris, H.; Uriac, Ph.; N'Diaye, M.; Lagadic-Gossmann, D.; Fardel, O.; Assemat, E.; Boublil, L.; Borot, M.C.; Marano, F.; Baeza-Squiban, A.; Martiny, V.Y.; Moroy, G.; Badel, A.; Miteva, M.A.; Hussain, S.; Ferecatu, I.; Borot, C.; Andreau, K.; Baeza-Squiban, A.; Marano, F.; Boland, S.; Leroux, M.; Zucchini-Pascal, N.; Peyre, L.; Rahmani, R.; Buron, N.; Porcedou, M.; Fromenty, B.; Borgne-Sanchez, A.; Rogue, A.; Spire, C.; Claude, N.; Guillouzo, A.

2010-01-01

Prevention of possible noxious effects in relation with the exposure to one or several chemical, physical or biological agents present in our domestic or professional environment is one of today's big public health stakes. Another stake is the better assessment of the risks linked with the use of health-care products. The efficacy and predictiveness of toxicology studies are directly related to the combination of alternate complementary methods and animal experiments (obtaining data from different species and with different models: in vitro, ex vivo and in vivo). Despite important efforts, the toxicological evaluation remains perfectible. The proceedings of this 2010 congress of the French Society of cell pharmaco-toxicology deal with recent advances, both scientific and technological, in 'predictive toxicology'. Four main topics are approached: cell and organ models, 'omics', in silico modeling, and new technologies (imaging, cell ships, high-speed processing). Among the different presentations, 3 abstracts present some recent advances in imaging techniques applied to toxicology studies. These are: 1 - first uses in toxicology of TOF-SIMS mass spectroscopy imaging (O. Laprevote, Paris-Descartes Univ. (FR)); 2 - Small animal imaging, a tool for predictive toxicology (A. Le Pape, CNRS Orleans (FR)); 3 - uranium localization at cell level using SIMS imaging technique (C. Rouas et al., IRSN Fontenay-aux-Roses (FR)). (J.S.)

Improved initial guess for minimum energy path calculations

International Nuclear Information System (INIS)

Smidstrup, Søren; Pedersen, Andreas; Stokbro, Kurt; Jónsson, Hannes

2014-01-01

A method is presented for generating a good initial guess of a transition path between given initial and final states of a system without evaluation of the energy. An objective function surface is constructed using an interpolation of pairwise distances at each discretization point along the path and the nudged elastic band method then used to find an optimal path on this image dependent pair potential (IDPP) surface. This provides an initial path for the more computationally intensive calculations of a minimum energy path on an energy surface obtained, for example, by ab initio or density functional theory. The optimal path on the IDPP surface is significantly closer to a minimum energy path than a linear interpolation of the Cartesian coordinates and, therefore, reduces the number of iterations needed to reach convergence and averts divergence in the electronic structure calculations when atoms are brought too close to each other in the initial path. The method is illustrated with three examples: (1) rotation of a methyl group in an ethane molecule, (2) an exchange of atoms in an island on a crystal surface, and (3) an exchange of two Si-atoms in amorphous silicon. In all three cases, the computational effort in finding the minimum energy path with DFT was reduced by a factor ranging from 50% to an order of magnitude by using an IDPP path as the initial path. The time required for parallel computations was reduced even more because of load imbalance when linear interpolation of Cartesian coordinates was used

Towards Predicting Efficient and Anonymous Tor Circuits

OpenAIRE

Barton, Armon; Imani, Mohsen; Ming, Jiang; Wright, Matthew

2018-01-01

The Tor anonymity system provides online privacy for millions of users, but it is slower than typical web browsing. To improve Tor performance, we propose PredicTor, a path selection technique that uses a Random Forest classifier trained on recent measurements of Tor to predict the performance of a proposed path. If the path is predicted to be fast, then the client builds a circuit using those relays. We implemented PredicTor in the Tor source code and show through live Tor experiments and Sh...

Solar array deployment analysis considering path-dependent behavior of a tape spring hinge

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung Won; Park, Young Jin [KAIST, Daejeon (Korea, Republic of)

2015-05-15

Solar array deployment analysis is conducted considering the path-dependent nonlinear behavior of tape spring hinge. Such hinges offer many advantages over rigid hinges; they are self-deployable, self-locking, lightweight, and simple. However, they show strongly nonlinear behavior with respect to rotation angle, making deployment analysis difficult. To accurately consider the characteristics of tape spring hinges for deployment analysis, a path-dependent path identification (PI) method for tracing the previous path of the moment is introduced. To analyze the deployment motion, the governing equation for solar array deployment is derived within the framework of Kane's dynamic equation for three deployable solar panels. The numerical solution is compared with the Recurdyn's multi-body dynamics analysis solution using experimentally measured moment-rotation profiles. Solar array deployment analysis is conducted by considering and not considering the path-dependent PI method. This simulation example shows that the proposed path-dependent PI method is very effective for accurately predicting the deployment motion.

Validation of RetroPath, a computer-aided design tool for metabolic pathway engineering.

Science.gov (United States)

Fehér, Tamás; Planson, Anne-Gaëlle; Carbonell, Pablo; Fernández-Castané, Alfred; Grigoras, Ioana; Dariy, Ekaterina; Perret, Alain; Faulon, Jean-Loup

2014-11-01

Metabolic engineering has succeeded in biosynthesis of numerous commodity or high value compounds. However, the choice of pathways and enzymes used for production was many times made ad hoc, or required expert knowledge of the specific biochemical reactions. In order to rationalize the process of engineering producer strains, we developed the computer-aided design (CAD) tool RetroPath that explores and enumerates metabolic pathways connecting the endogenous metabolites of a chassis cell to the target compound. To experimentally validate our tool, we constructed 12 top-ranked enzyme combinations producing the flavonoid pinocembrin, four of which displayed significant yields. Namely, our tool queried the enzymes found in metabolic databases based on their annotated and predicted activities. Next, it ranked pathways based on the predicted efficiency of the available enzymes, the toxicity of the intermediate metabolites and the calculated maximum product flux. To implement the top-ranking pathway, our procedure narrowed down a list of nine million possible enzyme combinations to 12, a number easily assembled and tested. One round of metabolic network optimization based on RetroPath output further increased pinocembrin titers 17-fold. In total, 12 out of the 13 enzymes tested in this work displayed a relative performance that was in accordance with its predicted score. These results validate the ranking function of our CAD tool, and open the way to its utilization in the biosynthesis of novel compounds. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Path Creation, Path Dependence and Breaking Away from the Path: Re-Examining the Case of Nokia

OpenAIRE

Wang, Jens; Hedman, Jonas; Tuunainen, Virpi Kristiina

2016-01-01

The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop and extend a multi-layer path dependence framework. We identify four layers of path dependence: technical, strategic and leadership, organizational, and external collaboration. We show how path dep...

Additional collection devices used in conjunction with the SurePath Liquid-Based Pap Test broom device do not enhance diagnostic utility

Directory of Open Access Journals (Sweden)

O'Connor Jason C

2004-09-01

Full Text Available Abstract Background We have previously shown that use of an EC brush device in combination with the Rovers Cervex-Brush (SurePath broom offered no significant improvement in EC recovery. Here we determine if use of additional collection devices enhance the diagnostic utility of the SurePath Pap for gynecologic cytology. Methods After informed consent, 37 women ages 18–56 receiving their routine cervical examinations were randomized into four experimental groups. Each group was first sampled with the SurePath broom then immediately re-sampled with an additional collection device or devices. Group 1: Rover endocervix brush (n = 8. Group 2: Medscand CytoBrush Plus GT (n = 7. Group 3: Rover spatula + endocervix brush (n = 11. Group 4: Medscand spatula + CytoBrush Plus GT (n = 11. Results Examination of SurePath broom-collected cytology yielded the following abnormal diagnoses: atypia (n = 2, LSIL (n = 5 and HSIL (n = 3. Comparison of these diagnoses to those obtained from paired samples using the additional collection devices showed that use of a second and or third device yielded no additional abnormal diagnoses. Importantly, use of additional devices did not improve upon the abnormal cell recovery of the SurePath broom and in 4/10 cases under-predicted or did not detect the SurePath broom-collected lesion as confirmed by cervical biopsy. Finally, in 36/37 cases, the SurePath broom successfully recovered ECs. Use of additional devices, in Group 3, augmented EC recovery to 37/37. Conclusions Use of additional collection devices in conjunction with the SurePath broom did not enhance diagnostic utility of the SurePath Pap. A potential but not significant improvement in EC recovery might be seen with the use of three devices.

A Path Tracking Algorithm Using Future Prediction Control with Spike Detection for an Autonomous Vehicle Robot

Directory of Open Access Journals (Sweden)

Muhammad Aizzat Zakaria

2013-08-01

Full Text Available Trajectory tracking is an important aspect of autonomous vehicles. The idea behind trajectory tracking is the ability of the vehicle to follow a predefined path with zero steady state error. The difficulty arises due to the nonlinearity of vehicle dynamics. Therefore, this paper proposes a stable tracking control for an autonomous vehicle. An approach that consists of steering wheel control and lateral control is introduced. This control algorithm is used for a non-holonomic navigation problem, namely tracking a reference trajectory in a closed loop form. A proposed future prediction point control algorithm is used to calculate the vehicle's lateral error in order to improve the performance of the trajectory tracking. A feedback sensor signal from the steering wheel angle and yaw rate sensor is used as feedback information for the controller. The controller consists of a relationship between the future point lateral error, the linear velocity, the heading error and the reference yaw rate. This paper also introduces a spike detection algorithm to track the spike error that occurs during GPS reading. The proposed idea is to take the advantage of the derivative of the steering rate. This paper aims to tackle the lateral error problem by applying the steering control law to the vehicle, and proposes a new path tracking control method by considering the future coordinate of the vehicle and the future estimated lateral error. The effectiveness of the proposed controller is demonstrated by a simulation and a GPS experiment with noisy data. The approach used in this paper is not limited to autonomous vehicles alone since the concept of autonomous vehicle tracking can be used in mobile robot platforms, as the kinematic model of these two platforms is similar.

Path-dependent functions

International Nuclear Information System (INIS)

Khrapko, R.I.

1985-01-01

A uniform description of various path-dependent functions is presented with the help of expansion of the type of the Taylor series. So called ''path-integrals'' and ''path-tensor'' are introduced which are systems of many-component quantities whose values are defined for arbitrary paths in coordinated region of space in such a way that they contain a complete information on the path. These constructions are considered as elementary path-dependent functions and are used instead of power monomials in the usual Taylor series. Coefficients of such an expansion are interpreted as partial derivatives dependent on the order of the differentiations or else as nonstandard cavariant derivatives called two-point derivatives. Some examples of pathdependent functions are presented.Space curvature tensor is considered whose geometrica properties are determined by the (non-transitive) translator of parallel transport of a general type. Covariant operation leading to the ''extension'' of tensor fiels is pointed out

Quantum cosmology based on discrete Feynman paths

International Nuclear Information System (INIS)

Chew, Geoffrey F.

2002-01-01

Although the rules for interpreting local quantum theory imply discretization of process, Lorentz covariance is usually regarded as precluding time quantization. Nevertheless a time-discretized quantum representation of redshifting spatially-homogeneous universe may be based on discrete-step Feynman paths carrying causal Lorentz-invariant action--paths that not only propagate the wave function but provide a phenomenologically-promising elementary-particle Hilbert-space basis. In a model under development, local path steps are at Planck scale while, at a much larger ''wave-function scale'', global steps separate successive wave-functions. Wave-function spacetime is but a tiny fraction of path spacetime. Electromagnetic and gravitational actions are ''at a distance'' in Wheeler-Feynman sense while strong (color) and weak (isospin) actions, as well as action of particle motion, are ''local'' in a sense paralleling the action of local field theory. ''Nonmaterial'' path segments and ''trivial events'' collaborate to define energy and gravity. Photons coupled to conserved electric charge enjoy privileged model status among elementary fermions and vector bosons. Although real path parameters provide no immediate meaning for ''measurement'', the phase of the complex wave function allows significance for ''information'' accumulated through ''gentle'' electromagnetic events involving charged matter and ''soft'' photons. Through its soft-photon content the wave function is an ''information reservoir''

Crystal plasticity-based modeling for predicting anisotropic behaviour and formability of metallic materials

International Nuclear Information System (INIS)

Pham, Son; Jeong, Youngung; Creuziger, Adam; Iadicola, Mark; Foecke, Tim; Rollett, Anthony

2016-01-01

Metallic materials often exhibit anisotropic behaviour under complex load paths because of changes in microstructure, e.g., dislocations and crystallographic texture. In this study, we present the development of constitutive model based on dislocations, point defects and texture in order to predict anisotropic response under complex load paths. In detail, dislocation/solute atom interactions were considered to account for strain aging and static recovery. A hardening matrix based on the interaction of dislocations was built to represent the cross-hardening of different slip systems. Clear differentiation between forward and backward slip directions of dislocations was made to describe back stresses during path changes. In addition, we included dynamic recovery in order to better account for large plastic deformation. The model is validated against experimental data for AA5754-O with path changes, e.g., Figure 1 [1] Another effort is to include microstructure in forming predictions with a minimal increase in computational time. This effort enables comprehensive investigations of the influence of texture-induced anisotropy on formability [2]. Application of these improvements to predict forming limits of various BCC textures, such as γ, ρ, α, η and ϵ fibers and a random (R) texture. These simulations demonstrate that the crystallographic texture has significant (both positive and negative) effects on the forming limit diagrams (Figure 2). For example, the y fiber texture, that is often sought through thermo-mechanical processing due to high r-value, had the highest forming limit in the balanced biaxial strain path but the lowest forming limit under the plane strain path among textures under consideration. (paper)

Probabilistic Path Planning of Montgolfier Balloons in Strong, Uncertain Wind Fields

Science.gov (United States)

Wolf, Michael; Blackmore, James C.; Kuwata, Yoshiaki

2011-01-01

Lighter-than-air vehicles such as hot-air balloons have been proposed for exploring Saturn s moon Titan, as well as other bodies with significant atmospheres. For these vehicles to navigate effectively, it is critical to incorporate the effects of surrounding wind fields, especially as these winds will likely be strong relative to the control authority of the vehicle. Predictive models of these wind fields are available, and previous research has considered problems of planning paths subject to these predicted forces. However, such previous work has considered the wind fields as known a priori, whereas in practical applications, the actual wind vector field is not known exactly and may deviate significantly from the wind velocities estimated by the model. A probabilistic 3D path-planning algorithm was developed for balloons to use uncertain wind models to generate time-efficient paths. The nominal goal of the algorithm is to determine what altitude and what horizontal actuation, if any is available on the vehicle, to use to reach a particular goal location in the least expected time, utilizing advantageous winds. The solution also enables one to quickly evaluate the expected time-to-goal from any other location and to avoid regions of large uncertainty. This method is designed for balloons in wind fields but may be generalized for any buoyant vehicle operating in a vector field. To prepare the planning problem, the uncertainty in the wind field is modeled. Then, the problem of reaching a particular goal location is formulated as a Markov decision process (MDP) using a discretized space approach. Solving the MDP provides a policy of what actuation option (how much buoyancy change and, if applicable, horizontal actuation) should be selected at any given location to minimize the expected time-to-goal. The results provide expected time-to-goal values from any given location on the globe in addition to the action policy. This stochastic approach can also provide

The Real World Significance of Performance Prediction

Science.gov (United States)

Pardos, Zachary A.; Wang, Qing Yang; Trivedi, Shubhendu

2012-01-01

In recent years, the educational data mining and user modeling communities have been aggressively introducing models for predicting student performance on external measures such as standardized tests as well as within-tutor performance. While these models have brought statistically reliable improvement to performance prediction, the real world…

Path selection rules for droplet trains in single-lane microfluidic networks

Science.gov (United States)

Amon, A.; Schmit, A.; Salkin, L.; Courbin, L.; Panizza, P.

2013-07-01

We investigate the transport of periodic trains of droplets through microfluidic networks having one inlet, one outlet, and nodes consisting of T junctions. Variations of the dilution of the trains, i.e., the distance between drops, reveal the existence of various hydrodynamic regimes characterized by the number of preferential paths taken by the drops. As the dilution increases, this number continuously decreases until only one path remains explored. Building on a continuous approach used to treat droplet traffic through a single asymmetric loop, we determine selection rules for the paths taken by the drops and we predict the variations of the fraction of droplets taking these paths with the parameters at play including the dilution. Our results show that as dilution decreases, the paths are selected according to the ascending order of their hydrodynamic resistance in the absence of droplets. The dynamics of these systems controlled by time-delayed feedback is complex: We observe a succession of periodic regimes separated by a wealth of bifurcations as the dilution is varied. In contrast to droplet traffic in single asymmetric loops, the dynamical behavior in networks of loops is sensitive to initial conditions because of extra degrees of freedom.

Transionospheric propagation predictions

Science.gov (United States)

Klobucher, J. A.; Basu, S.; Basu, S.; Bernhardt, P. A.; Davies, K.; Donatelli, D. E.; Fremouw, E. J.; Goodman, J. M.; Hartmann, G. K.; Leitinger, R.

1979-01-01

The current status and future prospects of the capability to make transionospheric propagation predictions are addressed, highlighting the effects of the ionized media, which dominate for frequencies below 1 to 3 GHz, depending upon the state of the ionosphere and the elevation angle through the Earth-space path. The primary concerns are the predictions of time delay of signal modulation (group path delay) and of radio wave scintillation. Progress in these areas is strongly tied to knowledge of variable structures in the ionosphere ranging from the large scale (thousands of kilometers in horizontal extent) to the fine scale (kilometer size). Ionospheric variability and the relative importance of various mechanisms responsible for the time histories observed in total electron content (TEC), proportional to signal group delay, and in irregularity formation are discussed in terms of capability to make both short and long term predictions. The data base upon which predictions are made is examined for its adequacy, and the prospects for prediction improvements by more theoretical studies as well as by increasing the available statistical data base are examined.

The experimental electron mean-free-path in Si under typical (S)TEM conditions

International Nuclear Information System (INIS)

Potapov, P.L.

2014-01-01

The electron mean-free-path in Si was measured by EELS using the test structure with the certified dimensions as a calibration standard. In a good agreement with the previous CBED measurements, the mean-free-path is 150 nm for 200 keV and 179 nm for 300 keV energy of primary electrons at large collection angles. These values are accurately predicted by the model of Iakoubovskii et al. while the model of Malis et al. incorporated in common microscopy software underestimates the mean-free-path by 15% at least. Correspondingly, the thickness of TEM samples reported in many studies of the Si-based materials last decades might be noticeably underestimated. - Highlights: • The electron inelastic mean-free-path in Si is measured for the typical (S)TEM conditions. • These reference values allow for accurate determination of the lamella thickness by EELS. • The theoretical model by Malis et al. underestimates the mean-free-path values

Multi-AGV path planning with double-path constraints by using an improved genetic algorithm.

Directory of Open Access Journals (Sweden)

Zengliang Han

Full Text Available This paper investigates an improved genetic algorithm on multiple automated guided vehicle (multi-AGV path planning. The innovations embody in two aspects. First, three-exchange crossover heuristic operators are used to produce more optimal offsprings for getting more information than with the traditional two-exchange crossover heuristic operators in the improved genetic algorithm. Second, double-path constraints of both minimizing the total path distance of all AGVs and minimizing single path distances of each AGV are exerted, gaining the optimal shortest total path distance. The simulation results show that the total path distance of all AGVs and the longest single AGV path distance are shortened by using the improved genetic algorithm.

Path planning in uncertain flow fields using ensemble method

KAUST Repository

Wang, Tong

2016-08-20

An ensemble-based approach is developed to conduct optimal path planning in unsteady ocean currents under uncertainty. We focus our attention on two-dimensional steady and unsteady uncertain flows, and adopt a sampling methodology that is well suited to operational forecasts, where an ensemble of deterministic predictions is used to model and quantify uncertainty. In an operational setting, much about dynamics, topography, and forcing of the ocean environment is uncertain. To address this uncertainty, the flow field is parametrized using a finite number of independent canonical random variables with known densities, and the ensemble is generated by sampling these variables. For each of the resulting realizations of the uncertain current field, we predict the path that minimizes the travel time by solving a boundary value problem (BVP), based on the Pontryagin maximum principle. A family of backward-in-time trajectories starting at the end position is used to generate suitable initial values for the BVP solver. This allows us to examine and analyze the performance of the sampling strategy and to develop insight into extensions dealing with general circulation ocean models. In particular, the ensemble method enables us to perform a statistical analysis of travel times and consequently develop a path planning approach that accounts for these statistics. The proposed methodology is tested for a number of scenarios. We first validate our algorithms by reproducing simple canonical solutions, and then demonstrate our approach in more complex flow fields, including idealized, steady and unsteady double-gyre flows.

Integral transforms of the quantum mechanical path integral: Hit function and path-averaged potential

Science.gov (United States)

Edwards, James P.; Gerber, Urs; Schubert, Christian; Trejo, Maria Anabel; Weber, Axel

2018-04-01

We introduce two integral transforms of the quantum mechanical transition kernel that represent physical information about the path integral. These transforms can be interpreted as probability distributions on particle trajectories measuring respectively the relative contribution to the path integral from paths crossing a given spatial point (the hit function) and the likelihood of values of the line integral of the potential along a path in the ensemble (the path-averaged potential).

Detection of deregulated modules using deregulatory linked path.

Directory of Open Access Journals (Sweden)

Yuxuan Hu

Full Text Available The identification of deregulated modules (such as induced by oncogenes is a crucial step for exploring the pathogenic process of complex diseases. Most of the existing methods focus on deregulation of genes rather than the links of the path among them. In this study, we emphasize on the detection of deregulated links, and develop a novel and effective regulatory path-based approach in finding deregulated modules. Observing that a regulatory pathway between two genes might involve in multiple rather than a single path, we identify condition-specific core regulatory path (CCRP to detect the significant deregulation of regulatory links. Using time-series gene expression, we define the regulatory strength within each gene pair based on statistical dependence analysis. The CCRPs in regulatory networks can then be identified using the shortest path algorithm. Finally, we derive the deregulated modules by integrating the differential edges (as deregulated links of the CCRPs between the case and the control group. To demonstrate the effectiveness of our approach, we apply the method to expression data associated with different states of Human Epidermal Growth Factor Receptor 2 (HER2. The experimental results show that the genes as well as the links in the deregulated modules are significantly enriched in multiple KEGG pathways and GO biological processes, most of which can be validated to suffer from impact of this oncogene based on previous studies. Additionally, we find the regulatory mechanism associated with the crucial gene SNAI1 significantly deregulated resulting from the activation of HER2. Hence, our method provides not only a strategy for detecting the deregulated links in regulatory networks, but also a way to identify concerning deregulated modules, thus contributing to the target selection of edgetic drugs.

Cyclic fatigue resistance of R-Pilot, WaveOne Gold Glider, and ProGlider glide path instruments.

Science.gov (United States)

Keskin, Cangül; İnan, Uğur; Demiral, Murat; Keleş, Ali

2018-02-17

The aim of the present study was to compare the cyclic fatigue resistance of R-Pilot (VDW; Munich, Germany) with ProGlider (Denstply Sirona; Ballaigues, Switzerland) and WaveOne Gold Glider (Denstply Sirona; Ballaigues, Switzerland) glide path instruments. R-Pilot, ProGlider, and WaveOne Gold Glider instruments were collected (n = 15) and tested in a dynamic cyclic fatigue test device, which has an artificial canal with 60° angle of curvature and a 5-mm radius of curvature. All instruments were operated until fracture occurred, and both time to fracture (TF) and the lengths of the fractured fragments were recorded. Mean and standard deviations of TF and fragment length were calculated for each reciprocating system. TF data and fractured fragment length data were subjected to one-way ANOVA and post-hoc Tukey tests (P  0.05). Weibull analysis revealed that WaveOne Gold Glider showed the highest predicted TF value for 99% survival rate, which was followed by R-Pilot and ProGlider. Regarding the length of the fractured tips, there were no significant differences among the instruments (P > 0.05). The reciprocating WaveOne Gold Glider and R-Pilot instruments had significantly higher cyclic fatigue resistance than rotary ProGlider instruments. This study reported that novel reciprocating glide path instruments exhibited higher cyclic fatigue resistance than rotating glide path instrument.

Open-path, closed-path and reconstructed aerosol extinction at a rural site.

Science.gov (United States)

Gordon, Timothy D; Prenni, Anthony J; Renfro, James R; McClure, Ethan; Hicks, Bill; Onasch, Timothy B; Freedman, Andrew; McMeeking, Gavin R; Chen, Ping

2018-04-09

The Handix Scientific Open-Path Cavity Ringdown Spectrometer (OPCRDS) was deployed during summer 2016 in Great Smoky Mountains National Park (GRSM). Extinction coefficients from the relatively new OPCRDS and from a more well-established extinction instrument agreed to within 7%. Aerosol hygroscopic growth (f(RH)) was calculated from the ratio of ambient extinction measured by the OPCRDS to dry extinction measured by a closed-path extinction monitor (Aerodyne's Cavity Attenuated Phase Shift Particulate Matter Extinction Monitor, CAPS PMex). Derived hygroscopicity (RH 1995 at the same site and time of year, which is noteworthy given the decreasing trend for organics and sulfate in the eastern U.S. However, maximum f(RH) values in 1995 were less than half as large as those recorded in 2016-possibly due to nephelometer truncation losses in 1995. Two hygroscopicity parameterizations were investigated using high time resolution OPCRDS+CAPS PMex data, and the K ext model was more accurate than the γ model. Data from the two ambient optical instruments, the OPCRDS and the open-path nephelometer, generally agreed; however, significant discrepancies between ambient scattering and extinction were observed, apparently driven by a combination of hygroscopic growth effects, which tend to increase nephelometer truncation losses and decrease sensitivity to the wavelength difference between the two instruments as a function of particle size. There was not a statistically significant difference in the mean reconstructed extinction values obtained from the original and the revised IMPROVE (Interagency Monitoring of Protected Visual Environments) equations. On average IMPROVE reconstructed extinction was ~25% lower than extinction measured by the OPCRDS, which suggests that the IMPROVE equations and 24-hr aerosol data are moderately successful in estimating current haze levels at GRSM. However, this conclusion is limited by the coarse temporal resolution and the low dynamic range of

Spreading paths in partially observed social networks

OpenAIRE

Onnela, Jukka-Pekka; Christakis, Nicholas A.

2012-01-01

Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, s...

Path-based Queries on Trajectory Data

DEFF Research Database (Denmark)

Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

2014-01-01

In traffic research, management, and planning a number of path-based analyses are heavily used, e.g., for computing turn-times, evaluating green waves, or studying traffic flow. These analyses require retrieving the trajectories that follow the full path being analyzed. Existing path queries cannot...... sufficiently support such path-based analyses because they retrieve all trajectories that touch any edge in the path. In this paper, we define and formalize the strict path query. This is a novel query type tailored to support path-based analysis, where trajectories must follow all edges in the path...... a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set...

Nonperturbative path integral expansion II

International Nuclear Information System (INIS)

Kaiser, H.J.

1976-05-01

The Feynman path integral representation of the 2-point function for a self-interacting Bose field is investigated using an expansion ('Path Integral Expansion', PIE) of the exponential of the kinetic term of the Lagrangian. This leads to a series - illustrated by a graph scheme - involving successively a coupling of more and more points of the lattice space commonly employed in the evaluation of path integrals. The values of the individual PIE graphs depend of course on the lattice constant. Two methods - Pade approximation and Borel-type extrapolation - are proposed to extract information about the continuum limit from a finite-order PIE. A more flexible PIE is possible by expanding besides the kinetic term a suitably chosen part of the interaction term too. In particular, if the co-expanded part is a mass term the calculation becomes only slightly more complicated than in the original formulation and the appearance of the graph scheme is unchanged. A significant reduction of the number of graphs and an improvement of the convergence of the PIE can be achieved by performing certain sums over an infinity of graph elements. (author)

NEW UPPER AND LOWER BOUNDS LINE OF SIGHT PATH LOSS MODELS FOR MOBILE PROPAGATION IN BUILDINGS

Directory of Open Access Journals (Sweden)

Supachai Phaiboon

2017-11-01

Full Text Available This paper proposes a method to predict line-of-sight (LOS path loss in buildings. We performed measurements in two different type of buildings at a frequency of 1.8 GHz and propose new upper and lower bounds path loss models which depend on max and min values of sample path loss data. This makes our models limit path loss within the boundary lines. The models include time-variant effects such as people moving and cars in parking areas with their influence on wave propagation that is very high.  The results have shown that the proposed models will be useful for the system and cell design of indoor wireless communication systems.

The concept of 'optimal' path in classical mechanics

International Nuclear Information System (INIS)

Passos, E.J.V. de; Cruz, F.F. de S.

1986-01-01

The significance of the concept of 'optimal' path in the framework of classical mechanics is discussed. The derivation of the local harmonic approximation and self-consistent collective coordinate method equations of the optimal path is based on a careful study of the concepts of local maximal decoupling and global maximal decoupling respectively. This exhibits the nature of the differences between these two theories and allows one to establish the conditions under which they become equivalent. (author)

Predicting Free Flow Speed and Crash Risk of Bicycle Traffic Flow Using Artificial Neural Network Models

Directory of Open Access Journals (Sweden)

Cheng Xu

2015-01-01

Full Text Available Free flow speed is a fundamental measure of traffic performance and has been found to affect the severity of crash risk. However, the previous studies lack analysis and modelling of impact factors on bicycles’ free flow speed. The main focus of this study is to develop multilayer back propagation artificial neural network (BPANN models for the prediction of free flow speed and crash risk on the separated bicycle path. Four different models with considering different combinations of input variables (e.g., path width, traffic condition, bicycle type, and cyclists’ characteristics were developed. 459 field data samples were collected from eleven bicycle paths in Hangzhou, China, and 70% of total samples were used for training, 15% for validation, and 15% for testing. The results show that considering the input variables of bicycle types and characteristics of cyclists will effectively improve the accuracy of the prediction models. Meanwhile, the parameters of bicycle types have more significant effect on predicting free flow speed of bicycle compared to those of cyclists’ characteristics. The findings could contribute for evaluation, planning, and management of bicycle safety.

Path integration quantization

International Nuclear Information System (INIS)

DeWitt-Morette, C.

1983-01-01

Much is expected of path integration as a quantization procedure. Much more is possible if one recognizes that path integration is at the crossroad of stochastic and differential calculus and uses the full power of both stochastic and differential calculus in setting up and computing path integrals. In contrast to differential calculus, stochastic calculus has only comparatively recently become an instrument of thought. It has nevertheless already been used in a variety of challenging problems, for instance in the quantization problem. The author presents some applications of the stochastic scheme. (Auth.)

Current-Sensitive Path Planning for an Underactuated Free-Floating Ocean Sensorweb

Science.gov (United States)

Dahl, Kristen P.; Thompson, David R.; McLaren, David; Chao, Yi; Chien, Steve

2011-01-01

This work investigates multi-agent path planning in strong, dynamic currents using thousands of highly under-actuated vehicles. We address the specific task of path planning for a global network of ocean-observing floats. These submersibles are typified by the Argo global network consisting of over 3000 sensor platforms. They can control their buoyancy to float at depth for data collection or rise to the surface for satellite communications. Currently, floats drift at a constant depth regardless of the local currents. However, accurate current forecasts have become available which present the possibility of intentionally controlling floats' motion by dynamically commanding them to linger at different depths. This project explores the use of these current predictions to direct float networks to some desired final formation or position. It presents multiple algorithms for such path optimization and demonstrates their advantage over the standard approach of constant-depth drifting.

The influence of parenting style on academic achievement and career path.

Science.gov (United States)

Zahed Zahedani, Zahra; Rezaee, Rita; Yazdani, Zahra; Bagheri, Sina; Nabeiei, Parisa

2016-07-01

Several factors affect the academic performance of college students and parenting style is one significant factor. The current study has been done with the purpose of investigating the relationship between parenting styles, academic achievement and career path of students at Shiraz University of Medical Sciences. This is a correlation study carried out at Shiraz University of Medical Sciences. Among 1600 students, 310 students were selected randomly as the sample. Baumrind's Parenting Style and Moqimi's Career Path questionnaires were used and the obtained scores were correlated with the students' transcripts. To study the relation between variables Pearson correlation coefficient was used. There was a significant relationship between authoritarian parenting style and educational success (p=0.03). Also findings showed a significant relationship between firm parenting style and Career Path of the students, authoritarian parenting style and Career Path of the students, educational success and Career Path of the students (p=0.001). Parents have an important role in identifying children's talent and guiding them. Mutual understanding and close relationship between parents and children are recommended. Therefore, it is recommended that the methods of correct interaction of parents and children be more valued and parents familiarize their children with roles of businesses in society and the need for employment in legitimate businesses and this important affair should be more emphasized through mass media and family training classes.

Reparametrization in the path integral

International Nuclear Information System (INIS)

Storchak, S.N.

1983-01-01

The question of the invariance of a measure in the n-dimensional path integral under the path reparametrization is considered. The non-invariance of the measure through the jacobian is suggeste. After the path integral reparametrization the representatioq for the Green's function of the Hamilton operator in terms of the path integral with the classical Hamiltonian has been obtained

Unique Path Partitions

DEFF Research Database (Denmark)

Bessenrodt, Christine; Olsson, Jørn Børling; Sellers, James A.

2013-01-01

We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions.......We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions....

Minimum free-energy paths for the self-organization of polymer brushes.

Science.gov (United States)

Gleria, Ignacio; Mocskos, Esteban; Tagliazucchi, Mario

2017-03-22

A methodology to calculate minimum free-energy paths based on the combination of a molecular theory and the improved string method is introduced and applied to study the self-organization of polymer brushes under poor solvent conditions. Polymer brushes in a poor solvent cannot undergo macroscopic phase separation due to the physical constraint imposed by the grafting points; therefore, they microphase separate forming aggregates. Under some conditions, the theory predicts that the homogeneous brush and the aggregates can exist as two different minima of the free energy. The theoretical methodology introduced in this work allows us to predict the minimum free-energy path connecting these two minima as well as the morphology of the system along the path. It is shown that the transition between the homogeneous brush and the aggregates may involve a free-energy barrier or be barrierless depending on the relative stability of the two morphologies and the chain length and grafting density of the polymer. In the case where a free-energy barrier exists, one of the morphologies is a metastable structure and, therefore, the properties of the brush as the quality of the solvent is cycled are expected to display hysteresis. The theory is also applied to study the adhesion/deadhesion transition between two opposing surfaces modified by identical polymer brushes and it is shown that this process may also require surpassing a free-energy barrier.

Magma paths at Piton de la Fournaise Volcano

OpenAIRE

Michon , Laurent; Ferrazzini , Valérie; Di Muro , Andrea

2016-01-01

International audience; Several patterns of magma paths have been proposed since the 1980s for Piton de la Fournaise volcano. Given the significant differences, which are presented here, we propose a reappraisal of the magma intrusion paths using a 17-years-long database of volcano-tectonic seismic events and a detailed mapping of the scoria cones. At the edifice scale, the magma propagates along two N120 trending rift zones. They are wide, linear, spotted by small to large scoria cones and r...

A Dynamic Bayesian Observer Model Reveals Origins of Bias in Visual Path Integration.

Science.gov (United States)

Lakshminarasimhan, Kaushik J; Petsalis, Marina; Park, Hyeshin; DeAngelis, Gregory C; Pitkow, Xaq; Angelaki, Dora E

2018-06-20

Path integration is a strategy by which animals track their position by integrating their self-motion velocity. To identify the computational origins of bias in visual path integration, we asked human subjects to navigate in a virtual environment using optic flow and found that they generally traveled beyond the goal location. Such a behavior could stem from leaky integration of unbiased self-motion velocity estimates or from a prior expectation favoring slower speeds that causes velocity underestimation. Testing both alternatives using a probabilistic framework that maximizes expected reward, we found that subjects' biases were better explained by a slow-speed prior than imperfect integration. When subjects integrate paths over long periods, this framework intriguingly predicts a distance-dependent bias reversal due to buildup of uncertainty, which we also confirmed experimentally. These results suggest that visual path integration in noisy environments is limited largely by biases in processing optic flow rather than by leaky integration. Copyright © 2018 Elsevier Inc. All rights reserved.

MPC-Based Path Following Control of an Omnidirectional Mobile Robot with Consideration of Robot Constraints

Directory of Open Access Journals (Sweden)

Kiattisin Kanjanawanishkul

2015-01-01

Full Text Available In this paper, the path following problem of an omnidirectional mobile robot (OMR has been studied. Unlike nonholonomic mobile robots, translational and rotational movements of OMRs can be controlled simultaneously and independently. However the constraints of translational and rotational velocities are coupled through the OMR's orientation angle. Therefore, a combination of a virtual-vehicle concept and a model predictive control (MPC strategy is proposed in this work to handle both robot constraints and the path following problem. Our proposed control scheme allows the OMR to follow the reference path successfully and safely, as illustrated in simulation experiments. The forward velocity is close to the desired one and the desired orientation angle is achieved at a given point on the path, while the robot's wheel velocities are maintained within boundaries.

Effectiveness of interactive tutorials in promoting "which-path" information reasoning in advanced quantum mechanics

Science.gov (United States)

Maries, Alexandru; Sayer, Ryan; Singh, Chandralekha

2017-12-01

Research suggests that introductory physics students often have difficulty using a concept in contexts different from the ones in which they learned it without explicit guidance to help them make the connection between the different contexts. We have been investigating advanced students' learning of quantum mechanics concepts and have developed interactive tutorials which strive to help students learn these concepts. Two such tutorials, focused on the Mach-Zehnder interferometer (MZI) and the double-slit experiment (DSE), help students learn how to use the concept of "which-path" information to reason about the presence or absence of interference in these two experiments in different situations. After working on a pretest that asked students to predict interference in the MZI with single photons and polarizers of various orientations placed in one or both paths of the MZI, students worked on the MZI tutorial which, among other things, guided them to reason in terms of which-path information in order to predict interference in similar situations. We investigated the extent to which students were able to use reasoning related to which-path information learned in the MZI tutorial to answer analogous questions on the DSE (before working on the DSE tutorial). After students worked on the DSE pretest they worked on a DSE tutorial in which they learned to use the concept of which-path information to answer questions about interference in the DSE with single particles with mass sent through the two slits and a monochromatic lamp placed between the slits and the screen. We investigated if this additional exposure to the concept of which-path information promoted improved learning and performance on the DSE questions with single photons and polarizers placed after one or both slits. We find evidence that both tutorials promoted which-path information reasoning and helped students use this reasoning appropriately in contexts different from the ones in which they had learned

Judgments in the selection of path generation techniques: a meta-analytic approach

DEFF Research Database (Denmark)

Prato, Carlo Giacomo

2012-01-01

objective judgments for effective route choice set generation. Initially, path generation techniques are implemented within a synthetic network to generate possible subjective choice sets considered by travelers. Next, “true model estimates” and “postulated predicted routes” are assumed from the simulation...... of a route choice model. Then, objective choice sets are applied for model estimation and results are compared to the “true model estimates”. Last, predictions from the simulation of models estimated with objective choice sets are compared to the “postulated predicted routes”. Meta-analysis allows...

Analysis Of Economic Motivation When Individuals Choose An Educational Path

Directory of Open Access Journals (Sweden)

Viktor Anatolyevich Koksharov

2015-03-01

Full Text Available The authors consider the economic motivations when individuals choose an educational path. This line of research is relevant from both, the point of view of science — research of economic behavior of an individual, and the point of view of practice — allows to increase efficiency of investments in a human capital. The authors have developed the economic and mathematical model of choice of optimum educational paths by individuals. The model is realized in the software and approved on real data on more than 5,5 thousand students. For the analysis of the importance of rational economic expectations when an educational path has to be chosen, the paths chosen by students is compared and the educational paths optimum from the point of view of economic rationality are calculated. The analysis of the results has showed that mainly, the choice of educational paths happens according to the economic motivations. On the considered selection, 66 % of prospective students have chosen an optimum path from the point of view of economic preferences. The most significant factor providing development of optimum educational paths is an expectation of higher income upon completion of education — 22 % of all educational paths, and a possibility of cost-cutting of educating or state-subsidized education — 12 %. In our opinion, one of the most important practical results of the research of optimum educational path is the need to consider expectations of students and prospective student when developing a state policy of investment in human capital.

Path Integrals in Quantum Mechanics

International Nuclear Information System (INIS)

Louko, J

2005-01-01

Jean Zinn-Justin's textbook Path Integrals in Quantum Mechanics aims to familiarize the reader with the path integral as a calculational tool in quantum mechanics and field theory. The emphasis is on quantum statistical mechanics, starting with the partition function Tr exp(-β H) and proceeding through the diffusion equation to barrier penetration problems and their semiclassical limit. The 'real time' path integral is defined via analytic continuation and used for the path-integral representation of the nonrelativistic S-matrix and its perturbative expansion. Holomorphic and Grassmannian path integrals are introduced and applied to nonrelativistic quantum field theory. There is also a brief discussion of path integrals in phase space. The introduction includes a brief historical review of path integrals, supported by a bibliography with some 40 entries. As emphasized in the introduction, mathematical rigour is not a central issue in the book. This allows the text to present the calculational techniques in a very readable manner: much of the text consists of worked-out examples, such as the quartic anharmonic oscillator in the barrier penetration chapter. At the end of each chapter there are exercises, some of which are of elementary coursework type, but the majority are more in the style of extended examples. Most of the exercises indeed include the solution or a sketch thereof. The book assumes minimal previous knowledge of quantum mechanics, and some basic quantum mechanical notation is collected in an appendix. The material has a large overlap with selected chapters in the author's thousand-page textbook Quantum Field Theory and Critical Phenomena (2002 Oxford: Clarendon). The stand-alone scope of the present work has, however, allowed a more focussed organization of this material, especially in the chapters on, respectively, holomorphic and Grassmannian path integrals. In my view the book accomplishes its aim admirably and is eminently usable as a textbook

Modeling Human Steering Behavior During Path Following in Teleoperation of Unmanned Ground Vehicles.

Science.gov (United States)

Mirinejad, Hossein; Jayakumar, Paramsothy; Ersal, Tulga

2018-04-01

This paper presents a behavioral model representing the human steering performance in teleoperated unmanned ground vehicles (UGVs). Human steering performance in teleoperation is considerably different from the performance in regular onboard driving situations due to significant communication delays in teleoperation systems and limited information human teleoperators receive from the vehicle sensory system. Mathematical models capturing the teleoperation performance are a key to making the development and evaluation of teleoperated UGV technologies fully simulation based and thus more rapid and cost-effective. However, driver models developed for the typical onboard driving case do not readily address this need. To fill the gap, this paper adopts a cognitive model that was originally developed for a typical highway driving scenario and develops a tuning strategy that adjusts the model parameters in the absence of human data to reflect the effect of various latencies and UGV speeds on driver performance in a teleoperated path-following task. Based on data collected from a human subject test study, it is shown that the tuned model can predict both the trend of changes in driver performance for different driving conditions and the best steering performance of human subjects in all driving conditions considered. The proposed model with the tuning strategy has a satisfactory performance in predicting human steering behavior in the task of teleoperated path following of UGVs. The established model is a suited candidate to be used in place of human drivers for simulation-based studies of UGV mobility in teleoperation systems.

The role of plastic slip anisotropy in the modelling of strain path change effects

NARCIS (Netherlands)

Viatkina, E.M.; Brekelmans, W.A.M.; Geers, M.G.D.

2009-01-01

Most industrial metal forming processes are characterised by a complex strain path history. A change in strain path may have a significant effect on the mechanical response of metals. This paper concentrates on the role of the plastic slip anisotropy in the strain path dependency of materials

Iterated Leavitt Path Algebras

International Nuclear Information System (INIS)

Hazrat, R.

2009-11-01

Leavitt path algebras associate to directed graphs a Z-graded algebra and in their simplest form recover the Leavitt algebras L(1,k). In this note, we introduce iterated Leavitt path algebras associated to directed weighted graphs which have natural ± Z grading and in their simplest form recover the Leavitt algebras L(n,k). We also characterize Leavitt path algebras which are strongly graded. (author)

Path Dependence

DEFF Research Database (Denmark)

Madsen, Mogens Ove

Begrebet Path Dependence blev oprindelig udviklet inden for New Institutionel Economics af bl.a. David, Arthur og North. Begrebet har spredt sig vidt i samfundsvidenskaberne og undergået en udvikling. Dette paper propagerer for at der er sket så en så omfattende udvikling af begrebet, at man nu kan...... tale om 1. og 2. generation af Path Dependence begrebet. Den nyeste udvikling af begrebet har relevans for metodologi-diskusionerne i relation til Keynes...

Road networks as collections of minimum cost paths

Science.gov (United States)

Wegner, Jan Dirk; Montoya-Zegarra, Javier Alexander; Schindler, Konrad

2015-10-01

We present a probabilistic representation of network structures in images. Our target application is the extraction of urban roads from aerial images. Roads appear as thin, elongated, partially curved structures forming a loopy graph, and this complex layout requires a prior that goes beyond standard smoothness and co-occurrence assumptions. In the proposed model the network is represented as a union of 1D paths connecting distant (super-)pixels. A large set of putative candidate paths is constructed in such a way that they include the true network as much as possible, by searching for minimum cost paths in the foreground (road) likelihood. Selecting the optimal subset of candidate paths is posed as MAP inference in a higher-order conditional random field. Each path forms a higher-order clique with a type of clique potential, which attracts the member nodes of cliques with high cumulative road evidence to the foreground label. That formulation induces a robust PN -Potts model, for which a global MAP solution can be found efficiently with graph cuts. Experiments with two road data sets show that the proposed model significantly improves per-pixel accuracies as well as the overall topological network quality with respect to several baselines.

Computing LS factor by runoff paths on TIN

Science.gov (United States)

Kavka, Petr; Krasa, Josef; Bek, Stanislav

2013-04-01

The article shows results of topographic factor (the LS factor in USLE) derivation enhancement focused on detailed Airborne Laser Scanning (ALS) based DEMs. It describes a flow paths generation technique using triangulated irregular network (TIN) for terrain morphology description, which is not yet established in soil loss computations. This technique was compared with other procedures of flow direction and flow paths generation based on commonly used raster model (DEM). These overland flow characteristics together with therefrom derived flow accumulation are significant inputs for many scientific models. Particularly they are used in all USLE-based soil erosion models, from which USLE2D, RUSLE3D, Watem/Sedem or USPED can be named as the most acknowledged. Flow routing characteristics are also essential parameters in physically based hydrological and soil erosion models like HEC-HMS, Wepp, Erosion3D, LISEM, SMODERP, etc. Mentioned models are based on regular raster grids, where the identification of runoff direction is problematic. The most common method is Steepest descent (one directional flow), which corresponds well with the concentration of surface runoff into concentrated flow. The Steepest descent algorithm for the flow routing doesn't provide satisfying results, it often creates parallel and narrow flow lines while not respecting real morphological conditions. To overcome this problem, other methods (such as Flux Decomposition, Multiple flow, Deterministic Infinity algorithm etc.) separate the outflow into several components. This approach leads to unrealistic diffusion propagation of the runoff and makes it impossible to be used for simulation of dominant morphological features, such as artificial rills, hedges, sediment traps etc. The modern methods of mapping ground elevations, especially ALS, provide very detailed models even for large river basins, including morphological details. New algorithms for derivation a runoff direction have been developed as

The influence of parenting style on academic achievement and career path

Directory of Open Access Journals (Sweden)

ZAHRA ZAHED ZAHEDANI

2016-07-01

Full Text Available Introduction: Several factors affect the academic performance of college students and parenting style is one significant factor. The current study has been done with the purpose of investigating the relationship between parenting styles, academic achievement and career path of students at Shiraz University of Medical Sciences. Methods: This is a correlation study carried out at Shiraz University of Medical Sciences. Among 1600 students, 310 students were selected randomly as the sample. Baumrind’s Parenting Style and Moqimi’s Career Path questionnaires were used and the obtained scores were correlated with the students’ transcripts. To study the relation between variables Pearson correlation coefficient was used. Results: There was a significant relationship between authoritarian parenting style and educational success (p=0.03. Also findings showed a significant relationship between firm parenting style and Career Path of the students, authoritarian parenting style and Career Path of the students, educational success and Career Path of the students (p=0.001. Conclusion: Parents have an important role in identifying children’s talent and guiding them. Mutual understanding and close relationship between parents and children are recommended. Therefore, it is recommended that the methods of correct interaction of parents and children be more valued and parents familiarize their children with roles of businesses in society and the need for employment in legitimate businesses and this important affair should be more emphasized through mass media and family training classes.

The influence of parenting style on academic achievement and career path

Science.gov (United States)

ZAHED ZAHEDANI, ZAHRA; REZAEE, RITA; YAZDANI, ZAHRA; BAGHERI, SINA; NABEIEI, PARISA

2016-01-01

Introduction Several factors affect the academic performance of college students and parenting style is one significant factor. The current study has been done with the purpose of investigating the relationship between parenting styles, academic achievement and career path of students at Shiraz University of Medical Sciences.     Methods This is a correlation study carried out at Shiraz University of Medical Sciences. Among 1600 students, 310 students were selected randomly as the sample. Baumrind’s Parenting Style and Moqimi’s Career Path questionnaires were used and the obtained scores were correlated with the students' transcripts. To study the relation between variables Pearson correlation coefficient was used. Results There was a significant relationship between authoritarian parenting style and educational success (p=0.03). Also findings showed a significant relationship between firm parenting style and Career Path of the students, authoritarian parenting style and Career Path of the students, educational success and Career Path of the students (p=0.001). Conclusion Parents have an important role in identifying children’s talent and guiding them. Mutual understanding and close relationship between parents and children are recommended. Therefore, it is recommended that the methods of correct interaction of parents and children be more valued and parents familiarize their children with roles of businesses in society and the need for employment in legitimate businesses and this important affair should be more emphasized through mass media and family training classes. PMID:27382580

Shortest Paths and Vehicle Routing

DEFF Research Database (Denmark)

Petersen, Bjørn

This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle...... Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown....

Path planning in changeable environments

NARCIS (Netherlands)

Nieuwenhuisen, D.

2007-01-01

This thesis addresses path planning in changeable environments. In contrast to traditional path planning that deals with static environments, in changeable environments objects are allowed to change their configurations over time. In many cases, path planning algorithms must facilitate quick

An adaptive dual-optimal path-planning technique for unmanned air vehicles

Directory of Open Access Journals (Sweden)

Whitfield Clifford A.

2016-01-01

Full Text Available A multi-objective technique for unmanned air vehicle path-planning generation through task allocation has been developed. The dual-optimal path-planning technique generates real-time adaptive flight paths based on available flight windows and environmental influenced objectives. The environmentally-influenced flight condition determines the aircraft optimal orientation within a downstream virtual window of possible vehicle destinations that is based on the vehicle’s kinematics. The intermittent results are then pursued by a dynamic optimization technique to determine the flight path. This path-planning technique is a multi-objective optimization procedure consisting of two goals that do not require additional information to combine the conflicting objectives into a single-objective. The technique was applied to solar-regenerative high altitude long endurance flight which can benefit significantly from an adaptive real-time path-planning technique. The objectives were to determine the minimum power required flight paths while maintaining maximum solar power for continual surveillance over an area of interest (AOI. The simulated path generation technique prolonged the flight duration over a sustained turn loiter flight path by approximately 2 months for a year of flight. The potential for prolonged solar powered flight was consistent for all latitude locations, including 2 months of available flight at 60° latitude, where sustained turn flight was no longer capable.

Comparison of classical reaction paths and tunneling paths studied with the semiclassical instanton theory.

Science.gov (United States)

Meisner, Jan; Markmeyer, Max N; Bohner, Matthias U; Kästner, Johannes

2017-08-30

Atom tunneling in the hydrogen atom transfer reaction of the 2,4,6-tri-tert-butylphenyl radical to 3,5-di-tert-butylneophyl, which has a short but strongly curved reaction path, was investigated using instanton theory. We found the tunneling path to deviate qualitatively from the classical intrinsic reaction coordinate, the steepest-descent path in mass-weighted Cartesian coordinates. To perform that comparison, we implemented a new variant of the predictor-corrector algorithm for the calculation of the intrinsic reaction coordinate. We used the reaction force analysis method as a means to decompose the reaction barrier into structural and electronic components. Due to the narrow energy barrier, atom tunneling is important in the abovementioned reaction, even above room temperature. Our calculated rate constants between 350 K and 100 K agree well with experimental values. We found a H/D kinetic isotope effect of almost 10 6 at 100 K. Tunneling dominates the protium transfer below 400 K and the deuterium transfer below 300 K. We compared the lengths of the tunneling path and the classical path for the hydrogen atom transfer in the reaction HCl + Cl and quantified the corner cutting in this reaction. At low temperature, the tunneling path is about 40% shorter than the classical path.

Cytological Evaluation and REBA HPV-ID HPV Testing of Newly Developed Liquid-Based Cytology, EASYPREP: Comparison with SurePath.

Science.gov (United States)

Lee, Youn Soo; Gong, Gyungyub; Sohn, Jin Hee; Ryu, Ki Sung; Lee, Jung Hun; Khang, Shin Kwang; Cho, Kyung-Ja; Kim, Yong-Man; Kang, Chang Suk

2013-06-01

The objective of this study was to evaluate a newly-developed EASYPREP liquid-based cytology method in cervicovaginal specimens and compare it with SurePath. Cervicovaginal specimens were prospectively collected from 1,000 patients with EASYPREP and SurePath. The specimens were first collected by brushing for SurePath and second for EASYPREP. The specimens of both methods were diagnosed according to the Bethesda System. Additionally, we performed to REBA HPV-ID genotyping and sequencing analysis for human papillomavirus (HPV) on 249 specimens. EASYPREP and SurePath showed even distribution of cells and were equal in cellularity and staining quality. The diagnostic agreement between the two methods was 96.5%. Based on the standard of SurePath, the sensitivity, specificity, positive predictive value, and negative predictive value of EASYPREP were 90.7%, 99.2%, 94.8%, and 98.5%, respectively. The positivity of REBA HPV-ID was 49.4% and 95.1% in normal and abnormal cytological samples, respectively. The result of REBA HPV-ID had high concordance with sequencing analysis. EASYPREP provided comparable results to SurePath in the diagnosis and staining quality of cytology examinations and in HPV testing with REBA HPV-ID. EASYPREP could be another LBC method choice for the cervicovaginal specimens. Additionally, REBA HPV-ID may be a useful method for HPV genotyping.

IntPath--an integrated pathway gene relationship database for model organisms and important pathogens.

Science.gov (United States)

Zhou, Hufeng; Jin, Jingjing; Zhang, Haojun; Yi, Bo; Wozniak, Michal; Wong, Limsoon

2012-01-01

Pathway data are important for understanding the relationship between genes, proteins and many other molecules in living organisms. Pathway gene relationships are crucial information for guidance, prediction, reference and assessment in biochemistry, computational biology, and medicine. Many well-established databases--e.g., KEGG, WikiPathways, and BioCyc--are dedicated to collecting pathway data for public access. However, the effectiveness of these databases is hindered by issues such as incompatible data formats, inconsistent molecular representations, inconsistent molecular relationship representations, inconsistent referrals to pathway names, and incomprehensive data from different databases. In this paper, we overcome these issues through extraction, normalization and integration of pathway data from several major public databases (KEGG, WikiPathways, BioCyc, etc). We build a database that not only hosts our integrated pathway gene relationship data for public access but also maintains the necessary updates in the long run. This public repository is named IntPath (Integrated Pathway gene relationship database for model organisms and important pathogens). Four organisms--S. cerevisiae, M. tuberculosis H37Rv, H. Sapiens and M. musculus--are included in this version (V2.0) of IntPath. IntPath uses the "full unification" approach to ensure no deletion and no introduced noise in this process. Therefore, IntPath contains much richer pathway-gene and pathway-gene pair relationships and much larger number of non-redundant genes and gene pairs than any of the single-source databases. The gene relationships of each gene (measured by average node degree) per pathway are significantly richer. The gene relationships in each pathway (measured by average number of gene pairs per pathway) are also considerably richer in the integrated pathways. Moderate manual curation are involved to get rid of errors and noises from source data (e.g., the gene ID errors in WikiPathways and

Computing paths and cycles in biological interaction graphs

Directory of Open Access Journals (Sweden)

von Kamp Axel

2009-06-01

Full Text Available Abstract Background Interaction graphs (signed directed graphs provide an important qualitative modeling approach for Systems Biology. They enable the analysis of causal relationships in cellular networks and can even be useful for predicting qualitative aspects of systems dynamics. Fundamental issues in the analysis of interaction graphs are the enumeration of paths and cycles (feedback loops and the calculation of shortest positive/negative paths. These computational problems have been discussed only to a minor extent in the context of Systems Biology and in particular the shortest signed paths problem requires algorithmic developments. Results We first review algorithms for the enumeration of paths and cycles and show that these algorithms are superior to a recently proposed enumeration approach based on elementary-modes computation. The main part of this work deals with the computation of shortest positive/negative paths, an NP-complete problem for which only very few algorithms are described in the literature. We propose extensions and several new algorithm variants for computing either exact results or approximations. Benchmarks with various concrete biological networks show that exact results can sometimes be obtained in networks with several hundred nodes. A class of even larger graphs can still be treated exactly by a new algorithm combining exhaustive and simple search strategies. For graphs, where the computation of exact solutions becomes time-consuming or infeasible, we devised an approximative algorithm with polynomial complexity. Strikingly, in realistic networks (where a comparison with exact results was possible this algorithm delivered results that are very close or equal to the exact values. This phenomenon can probably be attributed to the particular topology of cellular signaling and regulatory networks which contain a relatively low number of negative feedback loops. Conclusion The calculation of shortest positive

Assessing Receiving Water Quality Impacts due to Flow Path Alteration in Residential Catchments, using the Stormwater and Wastewater Management Model

Science.gov (United States)

Wolosoff, S. E.; Duncan, J.; Endreny, T.

2001-05-01

The Croton water supply system, responsible for supplying approximately 10% of New York City's water, provides an opportunity for exploration into the impacts of significant terrestrial flow path alteration upon receiving water quality. Natural flow paths are altered during residential development in order to allow for construction at a given location, reductions in water table elevation in low lying areas and to provide drainage of increased overland flow volumes. Runoff conducted through an artificial drainage system, is prevented from being attenuated by the natural environment, thus the pollutant removal capacity inherent in most natural catchments is often limited to areas where flow paths are not altered by development. By contrasting the impacts of flow path alterations in two small catchments in the Croton system, with different densities of residential development, we can begin to identify appropriate limits to the re-routing of runoff in catchments draining into surface water supplies. The Stormwater and Wastewater Management Model (SWMM) will be used as a tool to predict the runoff quantity and quality generated from two small residential catchments and to simulate the potential benefits of changes to the existing drainage system design, which may improve water quality due to longer residence times.

DiversePathsJ: diverse shortest paths for bioimage analysis.

Science.gov (United States)

Uhlmann, Virginie; Haubold, Carsten; Hamprecht, Fred A; Unser, Michael

2018-02-01

We introduce a formulation for the general task of finding diverse shortest paths between two end-points. Our approach is not linked to a specific biological problem and can be applied to a large variety of images thanks to its generic implementation as a user-friendly ImageJ/Fiji plugin. It relies on the introduction of additional layers in a Viterbi path graph, which requires slight modifications to the standard Viterbi algorithm rules. This layered graph construction allows for the specification of various constraints imposing diversity between solutions. The software allows obtaining a collection of diverse shortest paths under some user-defined constraints through a convenient and user-friendly interface. It can be used alone or be integrated into larger image analysis pipelines. http://bigwww.epfl.ch/algorithms/diversepathsj. michael.unser@epfl.ch or fred.hamprecht@iwr.uni-heidelberg.de. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

Mean free path dependent phonon contributions to interfacial thermal conductance

Energy Technology Data Exchange (ETDEWEB)

Tao, Yi; Liu, Chenhan; Chen, Weiyu; Cai, Shuang; Chen, Chen; Wei, Zhiyong; Bi, Kedong; Yang, Juekuan; Chen, Yunfei, E-mail: yunfeichen@seu.edu.cn

2017-06-15

Interfacial thermal conductance as an accumulation function of the phonon mean free path is rigorously derived from the thermal conductivity accumulation function. Based on our theoretical model, the interfacial thermal conductance accumulation function between Si/Ge is calculated. The results show that the range of mean free paths (MFPs) for phonons contributing to the interfacial thermal conductance is far narrower than that for phonons contributing to the thermal conductivity. The interfacial thermal conductance is mainly contributed by phonons with shorter MFPs, and the size effects can be observed only for an interface constructed by nanostructures with film thicknesses smaller than the MFPs of those phonons mainly contributing to the interfacial thermal conductance. This is why most experimental measurements cannot detect size effects on interfacial thermal conductance. A molecular dynamics simulation is employed to verify our proposed model. - Highlights: • A model to account for the interfacial thermal conductance as an accumulation function of phonon mean free path is proposed; • The model predicts that the range of mean free paths (MFPs) for phonons contributing to the interfacial thermal conductance is far narrower than that contributing to the thermal conductivity; • This model can be conveniently implemented to estimate the size effects on the interfacial thermal conductance for the interfaces formed by a nanostructure contacting a substrate.

Path integrals on curved manifolds

International Nuclear Information System (INIS)

Grosche, C.; Steiner, F.

1987-01-01

A general framework for treating path integrals on curved manifolds is presented. We also show how to perform general coordinate and space-time transformations in path integrals. The main result is that one has to subtract a quantum correction ΔV ∝ ℎ 2 from the classical Lagrangian L, i.e. the correct effective Lagrangian to be used in the path integral is L eff = L-ΔV. A general prescription for calculating the quantum correction ΔV is given. It is based on a canonical approach using Weyl-ordering and the Hamiltonian path integral defined by the midpoint prescription. The general framework is illustrated by several examples: The d-dimensional rotator, i.e. the motion on the sphere S d-1 , the path integral in d-dimensional polar coordinates, the exact treatment of the hydrogen atom in R 2 and R 3 by performing a Kustaanheimo-Stiefel transformation, the Langer transformation and the path integral for the Morse potential. (orig.)

Spatial interpolation of fine particulate matter concentrations using the shortest wind-field path distance.

Directory of Open Access Journals (Sweden)

Longxiang Li

Full Text Available Effective assessments of air-pollution exposure depend on the ability to accurately predict pollutant concentrations at unmonitored locations, which can be achieved through spatial interpolation. However, most interpolation approaches currently in use are based on the Euclidean distance, which cannot account for the complex nonlinear features displayed by air-pollution distributions in the wind-field. In this study, an interpolation method based on the shortest path distance is developed to characterize the impact of complex urban wind-field on the distribution of the particulate matter concentration. In this method, the wind-field is incorporated by first interpolating the observed wind-field from a meteorological-station network, then using this continuous wind-field to construct a cost surface based on Gaussian dispersion model and calculating the shortest wind-field path distances between locations, and finally replacing the Euclidean distances typically used in Inverse Distance Weighting (IDW with the shortest wind-field path distances. This proposed methodology is used to generate daily and hourly estimation surfaces for the particulate matter concentration in the urban area of Beijing in May 2013. This study demonstrates that wind-fields can be incorporated into an interpolation framework using the shortest wind-field path distance, which leads to a remarkable improvement in both the prediction accuracy and the visual reproduction of the wind-flow effect, both of which are of great importance for the assessment of the effects of pollutants on human health.

Navigating the Path to a Biomedical Science Career

Science.gov (United States)

Zimmerman, Andrea McNeely

The number of biomedical PhD scientists being trained and graduated far exceeds the number of academic faculty positions and academic research jobs. If this trend is compelling biomedical PhD scientists to increasingly seek career paths outside of academia, then more should be known about their intentions, desires, training experiences, and career path navigation. Therefore, the purpose of this study was to understand the process through which biomedical PhD scientists are trained and supported for navigating future career paths. In addition, the study sought to determine whether career development support efforts and opportunities should be redesigned to account for the proportion of PhD scientists following non-academic career pathways. Guided by the social cognitive career theory (SCCT) framework this study sought to answer the following central research question: How does a southeastern tier 1 research university train and support its biomedical PhD scientists for navigating their career paths? Key findings are: Many factors influence PhD scientists' career sector preference and job search process, but the most influential were relationships with faculty, particularly the mentor advisor; Planned activities are a significant aspect of the training process and provide skills for career success; and Planned activities provided skills necessary for a career, but influential factors directed the career path navigated. Implications for practice and future research are discussed.

Current distribution in parallel paths of the coils of a 50 Hz prototype dipole magnet

International Nuclear Information System (INIS)

Otter, A.J.

1995-06-01

The prototype dipole made for TRIUMF's Kaon Factory proposal used coils with 12 parallel paths to reduce eddy current losses in the conductors. The ac current distribution in these paths was non-uniform due to different self and mutual inductances. Small differences in inductance can cause large circulating currents in the parallel windings. This paper describes the measurement of the inductances and shows an attempt to predict the current distribution for two alternative connection schemes. (author). 4 refs., 8 figs

Hamiltonian path integrals

International Nuclear Information System (INIS)

Prokhorov, L.V.

1982-01-01

The properties of path integrals associated with the allowance for nonstandard terms reflecting the operator nature of the canonical variables are considered. Rules for treating such terms (''equivalence rules'') are formulated. Problems with a boundary, the behavior of path integrals under canonical transformations, and the problem of quantization of dynamical systems with constraints are considered in the framework of the method

Predictive toxicology: the paths of the future; Toxicologie predictive: les voies du futur

Energy Technology Data Exchange (ETDEWEB)

Detilleux, Ph.; Vallier, L.; Legallais, C.; Leclerc, E.; Prot, J.M.; Choucha, L.; Baudoin, R.; Dufresne, M.; Gautier, A.; Carpentier, B.; Mansuy, D.; Pery, A.; Brochot, C.; Manivet, Ph.; Rabilloud, Th.; Spire, C.; Coumoul, X.; Junot, Ch.; Laprevote, O.; Le pape, A.; Le Guevel, R.; Tourneur, E.; Ben Mkaddem, S.; Chassin, C.; Aloulou, M.; Goujon, J.M.; Hertif, A.; Ouali, N.; Vimont, S.; Monteiro, R.; Rondeau, E.; Elbim, C.; Werts, C.; Vandewalle, A.; Ben Mkaddem, S.; Pedruzzi, E.; Coant, N.; Bens, M.; Cluzeaud, F.; Ogier-Denis, E.; Pongnimitprasert, N.; Babin-Chevaye, C.; Fay, M.; Bernard, M.; Dupuy, C.; Ei Benna, J.; Gougerot-Pocidale, M.A.; Braut-Boucher, F.; Pinton, Ph.; Lucioli, J.; Tsybulskyy, D.; Joly, B.; Laffitte, J.; Bourges-Abella, N.; Oswald, I.P.; Kolf-Clauw, M.; Pierre, St.; Bats, A.S.; Chevallier, A.; Bui, L.Ch.; Ambolet-Camoit, A.; Garlatti, M.; Aggerbeck, M.; Barouki, R.; Al Khansa, I.; Blanck, O.; Guillouzo, A.; Bars, R.; Rouas, C.; Bensoussan, H.; Suhard, D.; Tessier, C.; Grandcolas, L.; Pallardy, M.; Gueguen, Y.; Sparfel, L.; Pinel-Marie, M.L.; Boize, M.; Koscielny, S.; Desmots, S.; Pery, A.; Fardel, O.; Alvergnas, M.; Rouleau, A.; Lucchi, G.; Mantion, G.; Heyd, B.; Richert, L.; Ducoroy, P.; Martin, H.; Val, St.; Martinon, L.; Cachier, H.; Yahyaoui, A.; Marfaing, H.; Baeza-Squiban, A.; Martin-Chouly, C.; Bonvallet, M.; Morzadec, C.; Fardel, O.; Vernhet, L.; Baverel, G.; El Hage, M.; Nazaret, R.; Conjard-Duplany, A.; Ferrier, B.; Martin, G.; Legendre, A.; Desmots, S.; Lecomte, A.; Froment, P.; Habert, R.; Lemazurier, E.; Robinel, F.; Dupont, O.; Sanfins, E.; Dairou, J.; Chaffotte, A.F.; Busi, F.; Rodrigues Lima, F.; Dupret, J.M.; Mayati, A.; Le Ferrec, E.; Levoin, N.; Paris, H.; Uriac, Ph.; N' Diaye, M.; Lagadic-Gossmann, D.; Fardel, O.; Assemat, E.; Boublil, L.; Borot, M.C.; Marano, F.; Baeza-Squiban, A.; Martiny, V.Y.; Moroy, G.; Badel, A.; Miteva, M.A.; Hussain, S.; Ferecatu, I.; Borot, C.; Andreau, K.; Baeza-Squiban, A. [and others

2010-07-01

Prevention of possible noxious effects in relation with the exposure to one or several chemical, physical or biological agents present in our domestic or professional environment is one of today's big public health stakes. Another stake is the better assessment of the risks linked with the use of health-care products. The efficacy and predictiveness of toxicology studies are directly related to the combination of alternate complementary methods and animal experiments (obtaining data from different species and with different models: in vitro, ex vivo and in vivo). Despite important efforts, the toxicological evaluation remains perfectible. The proceedings of this 2010 congress of the French Society of cell pharmaco-toxicology deal with recent advances, both scientific and technological, in 'predictive toxicology'. Four main topics are approached: cell and organ models, 'omics', in silico modeling, and new technologies (imaging, cell ships, high-speed processing). Among the different presentations, 3 abstracts present some recent advances in imaging techniques applied to toxicology studies. These are: 1 - first uses in toxicology of TOF-SIMS mass spectroscopy imaging (O. Laprevote, Paris-Descartes Univ. (FR)); 2 - Small animal imaging, a tool for predictive toxicology (A. Le Pape, CNRS Orleans (FR)); 3 - uranium localization at cell level using SIMS imaging technique (C. Rouas et al., IRSN Fontenay-aux-Roses (FR)). (J.S.)

Symbolic PathFinder v7

DEFF Research Database (Denmark)

Luckow, Kasper Søe; Păsăreanu, Corina

2014-01-01

We describe Symbolic PathFinder v7 in terms of its updated design addressing the changes of Java PathFinder v7 and of its new optimization when computing path conditions. Furthermore, we describe the Symbolic Execution Tree Extension; a newly added feature that allows for outputting the symbolic...... execution tree that characterizes the execution paths covered during symbolic execution. The new extension can be tailored to the needs of subsequent analyses/processing facilities, and we demonstrate this by presenting SPF-Visualizer, which is a tool for customizable visualization of the symbolic execution...

Using wind tunnels to predict bird mortality in wind farms: the case of griffon vultures.

Science.gov (United States)

de Lucas, Manuela; Ferrer, Miguel; Janss, Guyonne F E

2012-01-01

Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topography and wind flows in relation to flight paths of griffon vultures, using a scaled model of the wind farm area in an aerodynamic wind tunnel, and test the difference between the observed flight paths of griffon vultures and the predominant wind flows. Different wind currents for each wind direction in the aerodynamic model were observed. Simulations of wind flows in a wind tunnel were compared with observed flight paths of griffon vultures. No statistical differences were detected between the observed flight trajectories of griffon vultures and the wind passages observed in our wind tunnel model. A significant correlation was found between dead vultures predicted proportion of vultures crossing those cells according to the aerodynamic model. Griffon vulture flight routes matched the predominant wind flows in the area (i.e. they followed the routes where less flight effort was needed). We suggest using these kinds of simulations to predict flight paths over complex terrains can inform the location of wind turbines and thereby reduce soaring bird mortality.

MEASURING PATH DEPENDENCY

Directory of Open Access Journals (Sweden)

Peter Juhasz

2017-03-01

Full Text Available While risk management gained popularity during the last decades even some of the basic risk types are still far out of focus. One of these is path dependency that refers to the uncertainty of how we reach a certain level of total performance over time. While decision makers are careful in accessing how their position will look like the end of certain periods, little attention is given how they will get there through the period. The uncertainty of how a process will develop across a shorter period of time is often “eliminated” by simply choosing a longer planning time interval, what makes path dependency is one of the most often overlooked business risk types. After reviewing the origin of the problem we propose and compare seven risk measures to access path. Traditional risk measures like standard deviation of sub period cash flows fail to capture this risk type. We conclude that in most cases considering the distribution of the expected cash flow effect caused by the path dependency may offer the best method, but we may need to use several measures at the same time to include all the optimisation limits of the given firm

Model training across multiple breeding cycles significantly improves genomic prediction accuracy in rye (Secale cereale L.).

Science.gov (United States)

Auinger, Hans-Jürgen; Schönleben, Manfred; Lehermeier, Christina; Schmidt, Malthe; Korzun, Viktor; Geiger, Hartwig H; Piepho, Hans-Peter; Gordillo, Andres; Wilde, Peer; Bauer, Eva; Schön, Chris-Carolin

2016-11-01

Genomic prediction accuracy can be significantly increased by model calibration across multiple breeding cycles as long as selection cycles are connected by common ancestors. In hybrid rye breeding, application of genome-based prediction is expected to increase selection gain because of long selection cycles in population improvement and development of hybrid components. Essentially two prediction scenarios arise: (1) prediction of the genetic value of lines from the same breeding cycle in which model training is performed and (2) prediction of lines from subsequent cycles. It is the latter from which a reduction in cycle length and consequently the strongest impact on selection gain is expected. We empirically investigated genome-based prediction of grain yield, plant height and thousand kernel weight within and across four selection cycles of a hybrid rye breeding program. Prediction performance was assessed using genomic and pedigree-based best linear unbiased prediction (GBLUP and PBLUP). A total of 1040 S 2 lines were genotyped with 16 k SNPs and each year testcrosses of 260 S 2 lines were phenotyped in seven or eight locations. The performance gap between GBLUP and PBLUP increased significantly for all traits when model calibration was performed on aggregated data from several cycles. Prediction accuracies obtained from cross-validation were in the order of 0.70 for all traits when data from all cycles (N CS  = 832) were used for model training and exceeded within-cycle accuracies in all cases. As long as selection cycles are connected by a sufficient number of common ancestors and prediction accuracy has not reached a plateau when increasing sample size, aggregating data from several preceding cycles is recommended for predicting genetic values in subsequent cycles despite decreasing relatedness over time.

Religious beliefs along the suicidal path in northern Taiwan.

Science.gov (United States)

Fang, Chun-Kai; Lu, Hsin-Chin; Liu, Shen-ing; Sun, Yi-Wen

2011-01-01

This study aimed to understand the current inclinations toward depression and compulsion for members of four different religious groups, and to predict religious beliefs along the suicide path through analyzing the lifetime prevalence of suicidal ideation and suicide attempts for members of these religious groups. Participants in this cross-sectional study, which adopted purposive sampling, were members of Christianity, Catholicism, Buddhism, and Taoism in northern Taiwan. In the case of suicide experiences, suicides among people one knows, and tendency toward compulsion and depression, there are statistical differences between the four religions. According to the results, some people with suicidal tendency will attend religious activities; therefore, we predict that religious beliefs play an important role in suicide prevention.

A new model using routinely available clinical parameters to predict significant liver fibrosis in chronic hepatitis B.

Directory of Open Access Journals (Sweden)

Wai-Kay Seto

Full Text Available OBJECTIVE: We developed a predictive model for significant fibrosis in chronic hepatitis B (CHB based on routinely available clinical parameters. METHODS: 237 treatment-naïve CHB patients [58.4% hepatitis B e antigen (HBeAg-positive] who had undergone liver biopsy were randomly divided into two cohorts: training group (n = 108 and validation group (n = 129. Liver histology was assessed for fibrosis. All common demographics, viral serology, viral load and liver biochemistry were analyzed. RESULTS: Based on 12 available clinical parameters (age, sex, HBeAg status, HBV DNA, platelet, albumin, bilirubin, ALT, AST, ALP, GGT and AFP, a model to predict significant liver fibrosis (Ishak fibrosis score ≥3 was derived using the five best parameters (age, ALP, AST, AFP and platelet. Using the formula log(index+1 = 0.025+0.0031(age+0.1483 log(ALP+0.004 log(AST+0.0908 log(AFP+1-0.028 log(platelet, the PAPAS (Platelet/Age/Phosphatase/AFP/AST index predicts significant fibrosis with an area under the receiving operating characteristics (AUROC curve of 0.776 [0.797 for patients with ALT <2×upper limit of normal (ULN] The negative predictive value to exclude significant fibrosis was 88.4%. This predictive power is superior to other non-invasive models using common parameters, including the AST/platelet/GGT/AFP (APGA index, AST/platelet ratio index (APRI, and the FIB-4 index (AUROC of 0.757, 0.708 and 0.723 respectively. Using the PAPAS index, 67.5% of liver biopsies for patients being considered for treatment with ALT <2×ULN could be avoided. CONCLUSION: The PAPAS index can predict and exclude significant fibrosis, and may reduce the need for liver biopsy in CHB patients.

Path integration in conical space

International Nuclear Information System (INIS)

Inomata, Akira; Junker, Georg

2012-01-01

Quantum mechanics in conical space is studied by the path integral method. It is shown that the curvature effect gives rise to an effective potential in the radial path integral. It is further shown that the radial path integral in conical space can be reduced to a form identical with that in flat space when the discrete angular momentum of each partial wave is replaced by a specific non-integral angular momentum. The effective potential is found proportional to the squared mean curvature of the conical surface embedded in Euclidean space. The path integral calculation is compatible with the Schrödinger equation modified with the Gaussian and the mean curvature. -- Highlights: ► We study quantum mechanics on a cone by the path integral approach. ► The path integral depends only on the metric and the curvature effect is built in. ► The approach is consistent with the Schrödinger equation modified by an effective potential. ► The effective potential is found to be of the “Jensen–Koppe” and “da Costa” type.

Meta-Analysis of Predictive Significance of the Black Hole Sign for Hematoma Expansion in Intracerebral Hemorrhage.

Science.gov (United States)

Zheng, Jun; Yu, Zhiyuan; Guo, Rui; Li, Hao; You, Chao; Ma, Lu

2018-04-27

Hematoma expansion is related to unfavorable prognosis in intracerebral hemorrhage (ICH). The black hole sign is a novel marker on non-contrast computed tomography for predicting hematoma expansion. However, its predictive values are different in previous studies. Thus, this meta-analysis was conducted to evaluate the predictive significance of the black hole sign for hematoma expansion in ICH. A systematic literature search was performed. Original researches on the association between the black hole sign and hematoma expansion in ICH were included. Sensitivity and specificity were pooled to assess the predictive accuracy. Summary receiver operating characteristics curve (SROC) was developed. Deeks' funnel plot asymmetry test was used to assess the publication bias. Five studies with a total of 1495 patients were included in this study. The pooled sensitivity and specificity of the black hole sign for predicting hematoma expansion were 0.30 and 0.91, respectively. The area under the curve was 0.78 in SROC curve. There was no significant publication bias. This meta-analysis shows that the black hole sign is a helpful imaging marker for predicting hematoma expansion in ICH. Although the black hole sign has a relatively low sensitivity, its specificity is relatively high. Copyright © 2018 Elsevier Inc. All rights reserved.

Combining water-rock interaction experiments with reaction path and reactive transport modelling to predict reservoir rock evolution in an enhanced geothermal system

Science.gov (United States)

Kuesters, Tim; Mueller, Thomas; Renner, Joerg

2016-04-01

Reliably predicting the evolution of mechanical and chemical properties of reservoir rocks is crucial for efficient exploitation of enhanced geothermal systems (EGS). For example, dissolution and precipitation of individual rock forming minerals often result in significant volume changes, affecting the hydraulic rock properties and chemical composition of fluid and solid phases. Reactive transport models are typically used to evaluate and predict the effect of the internal feedback of these processes. However, a quantitative evaluation of chemo-mechanical interaction in polycrystalline environments is elusive due to poorly constrained kinetic data of complex mineral reactions. In addition, experimentally derived reaction rates are generally faster than reaction rates determined from natural systems, likely a consequence of the experimental design: a) determining the rate of a single process only, e.g. the dissolution of a mineral, and b) using powdered sample materials and thus providing an unrealistically high reaction surface and at the same time eliminating the restrictions on element transport faced in-situ for fairly dense rocks. In reality, multiple reactions are coupled during the alteration of a polymineralic rocks in the presence of a fluid and the rate determining process of the overall reactions is often difficult to identify. We present results of bulk rock-water interaction experiments quantifying alteration reactions between pure water and a granodiorite sample. The rock sample was chosen for its homogenous texture, small and uniform grain size (˜0.5 mm in diameter), and absence of pre-existing alteration features. The primary minerals are plagioclase (plg - 58 vol.%), quartz (qtz - 21 vol.%), K-feldspar (Kfs - 17 vol.%), biotite (bio - 3 vol.%) and white mica (wm - 1 vol.%). Three sets of batch experiments were conducted at 200 ° C to evaluate the effect of reactive surface area and different fluid path ways using (I) powders of the bulk rock with

Two dimensional simplicial paths

International Nuclear Information System (INIS)

Piso, M.I.

1994-07-01

Paths on the R 3 real Euclidean manifold are defined as 2-dimensional simplicial strips which are orbits of the action of a discrete one-parameter group. It is proven that there exists at least one embedding of R 3 in the free Z-module generated by S 2 (x 0 ). The speed is defined as the simplicial derivative of the path. If mass is attached to the simplex, the free Lagrangian is proportional to the width of the path. In the continuum limit, the relativistic form of the Lagrangian is recovered. (author). 7 refs

Predictive Index The Incidence Of Tuberculosis Children In South Kalimantan Province

Directory of Open Access Journals (Sweden)

Bahrul Ilmi

2015-08-01

Full Text Available The research objective to formulate predictive index of Tuberculosis Children in South Kalimantan province. Research methods combined mixed methods with a combination of research model Sequential Exploratory Design qualitative approach to support quantitative and centered on quantitative Sugiono 2012 case control design. The number of qualitative sample was 16 respondents to interviews and 48 respondents for FGD. The number of quantitative research sample was 216 consisted of 62 cases and 154 controls. Qualitative sampling by purposive sampling and quantitative Multi-stage Cluster random sampling on 3 stages. The analysis technique used is descriptive qualitative and Confirmatory Factor Analysis Confirmatory Factor Analysis measure the latent of variables by using path analysis path analysis with the program Linear Structural Relationships LISREL. The results showed a positive effect on the socio-cultural environment and significantly associated with the incidence of Tuberculosis Children. While the physical environment of the house positively and significantly with biological environments and the incidence of Tuberculosis Children and immunization and nutrition status of children positively and significantly to the incidence of Tuberculosis of the Child as well as to the biological environment positive and significant effect on the incidence of TB Children. Formulation Predictive Index of Tuberculosis Children in South Kalimantan province. is index 019 Physical Environment Home 044 053 Biological Environment Social Environment Culture 019 Status Immunization and Child Nutrition. The results of all the R-square value indicates that all of the R-square values 0.5. This means that a predictive model of TB Kids index has met the required Goodness of Fit. New findings from research of this dissertation are 1. Research Variable of social networks social support and collective efficacy were associated with the incidence of Tuberculosis Children. 2

Masticatory path pattern during mastication of chewing gum with regard to gender difference.

Science.gov (United States)

Kobayashi, Yoshinori; Shiga, Hiroshi; Arakawa, Ichiro; Yokoyama, Masaoki; Nakajima, Kunihisa

2009-01-01

To clarify the masticatory path patterns of the mandibular incisal point during mastication of softened chewing gum with regard to gender difference. One hundred healthy subjects (50 males and 50 females) were asked to chew softened chewing gum on one side at a time (right side and left side) and the movement of the mandibular incisal point was recorded using MKG K6I. After a catalog of path patterns was made, the movement path was classified into one of the pattern groups, and then the frequency of each pattern was investigated. A catalog of path patterns consisting of the three types of opening path (op1, linear or concave path; op2, path toward the chewing side after toward the non-working side; op3, convex path) and two types of closing path (cl1, convex path; cl2, concave path) was made. The movement path was classified into one of seven patterns, with six patterns being from the catalog and a final extra pattern in which the opening and closing paths crossed. The most common pattern among the subjects was Pattern I, followed by Patterns III, II, IV, V, VII, and VI, in that order. The majority of cases, 149 (74.5%) of 200 cases, showed either Pattern I (op1 and cl1) or Pattern III (op2 and cl1). There was no significant difference between the two genders in the frequency of each pattern. The movement path could be classified into seven patterns and no gender-related difference was found in the frequency of each pattern.

Path coefficient analysis of zinc dynamics in varying soil environment

International Nuclear Information System (INIS)

Rattan, R.K.; Phung, C.V.; Singhal, S.K.; Deb, D.L.; Singh, A.K.

1994-01-01

Influence of soil properties on labile zinc, as measured by diethylene-triamine pentaacetic acid (DTPA) and zinc-65, and self-diffusion coefficients of zinc was assessed on 22 surface soil samples varying widely in their characteristics following linear regression and path coefficient analysis techniques. DTPA extractable zinc could be predicted from organic carbon status and pH of the soil with a highly significant coefficient of determination (R 2 =0.84 ** ). Ninety seven per cent variation in isotopically exchangeable zinc was explained by pH, clay content and cation exchange capacity (CEC) of soil. The self-diffusion coefficients (DaZn and DpZn) and buffer power of zinc exhibited exponential relationship with soil properties, pH being the most dominant one. Soil properties like organic matter, clay content etc. exhibited indirect effects on zinc diffusion rates via pH only. (author). 13 refs., 6 tabs

Evolvable Neuronal Paths: A Novel Basis for Information and Search in the Brain

Science.gov (United States)

Fernando, Chrisantha; Vasas, Vera; Szathmáry, Eörs; Husbands, Phil

2011-01-01

We propose a previously unrecognized kind of informational entity in the brain that is capable of acting as the basis for unlimited hereditary variation in neuronal networks. This unit is a path of activity through a network of neurons, analogous to a path taken through a hidden Markov model. To prove in principle the capabilities of this new kind of informational substrate, we show how a population of paths can be used as the hereditary material for a neuronally implemented genetic algorithm, (the swiss-army knife of black-box optimization techniques) which we have proposed elsewhere could operate at somatic timescales in the brain. We compare this to the same genetic algorithm that uses a standard ‘genetic’ informational substrate, i.e. non-overlapping discrete genotypes, on a range of optimization problems. A path evolution algorithm (PEA) is defined as any algorithm that implements natural selection of paths in a network substrate. A PEA is a previously unrecognized type of natural selection that is well suited for implementation by biological neuronal networks with structural plasticity. The important similarities and differences between a standard genetic algorithm and a PEA are considered. Whilst most experiments are conducted on an abstract network model, at the conclusion of the paper a slightly more realistic neuronal implementation of a PEA is outlined based on Izhikevich spiking neurons. Finally, experimental predictions are made for the identification of such informational paths in the brain. PMID:21887266

Bilirubin nomogram for prediction of significant hyperbilirubinemia in north Indian neonates.

Science.gov (United States)

Pathak, Umesh; Chawla, Deepak; Kaur, Saranjit; Jain, Suksham

2013-04-01

(i) To construct hour-specific serum total bilirubin (STB) nomogram in neonates born at =35 weeks of gestation; (ii)To evaluate efficacy of pre-discharge bilirubin measurement in predicting hyperbilirubinemia needing treatment. Diagnostic test performance in a prospective cohort study. Teaching hospital in Northern India. Healthy neonates with gestation =35 weeks or birth weight =2000 g. Serum total bilirubin was measured in all enrolled neonates at 24 ± 6, 72-96 and 96-144 h of postnatal age and when indicated clinically. Neonates were followed up during hospital stay and after discharge till completion of 7th postnatal day. Key outcome was significant hyperbilirubinemia (SHB) defined as need of phototherapy based on modified American Academy of Pediatrics (AAP) guidelines. In neonates born at 38 or more weeks of gestation middle line and in neonates born at 37 or less completed weeks of gestation, lower line of phototherapy thresholds were used to initiate phototherapy. For construction of nomogram, STB values were clubbed in six-hour epochs (age ± 3 hours) for postnatal age up to 48 h and twelve-hour epochs (age ± 6 hours) for age beyond 48 h. Predictive ability of the nomogram was assessed by calculating sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratio, by plotting receiver-operating characteristics (ROC) curve and calculating c-statistic. 997 neonates (birth weight: 2627 ± 536 g, gestation: 37.8 ± 1.5 weeks) were enrolled, of which 931 completed followup. Among enrolled neonates 344 (34.5%) were low birth weight. Rate of exclusive breastfeeding during hospital stay was more than 80%. Bilirubin nomogram was constructed using 40th, 75th and 95th percentile values of hour-specific bilirubin. Pre-discharge STB of =95th percentile was assigned to be in high-risk zone, between 75th and 94th centile in upper-intermediate risk zone, between 40th and 74th centile in lower-intermediate risk zone and below 40th

Decision paths in complex tasks

Science.gov (United States)

Galanter, Eugene

1991-01-01

Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

Root canal anatomy preservation of WaveOne reciprocating files with or without glide path.

Science.gov (United States)

Berutti, Elio; Paolino, Davide Salvatore; Chiandussi, Giorgio; Alovisi, Mario; Cantatore, Giuseppe; Castellucci, Arnaldo; Pasqualini, Damiano

2012-01-01

This study evaluated the influence of glide path on canal curvature and axis modification after instrumentation with WaveOne Primary reciprocating files. Thirty ISO 15, 0.02 taper Endo Training Blocks were used. In group 1, glide path was created with PathFile 1, 2, and 3 at working length, whereas in group 2, glide path was not performed. In both groups, canals were shaped with WaveOne Primary reciprocating files at working length. Preinstrumentation and postinstrumentation digital images were superimposed and processed with Matlab r2010b software to analyze the curvature radius ratio (CRr) and the relative axis error (rAe), representing canal curvature modification. Data were analyzed with 1-way balanced analyses of variance at 2 levels (P < .05). Glide path was found to be extremely significant for both CRr parameter (F = 9.59; df = 1; P = .004) and rAe parameter (F = 13.55; df = 1; P = .001). Canal modifications seem to be significantly reduced when previous glide path is performed by using the new WaveOne nickel-titanium single-file system. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Reduce manual curation by combining gene predictions from multiple annotation engines, a case study of start codon prediction.

Directory of Open Access Journals (Sweden)

Thomas H A Ederveen

Full Text Available Nowadays, prokaryotic genomes are sequenced faster than the capacity to manually curate gene annotations. Automated genome annotation engines provide users a straight-forward and complete solution for predicting ORF coordinates and function. For many labs, the use of AGEs is therefore essential to decrease the time necessary for annotating a given prokaryotic genome. However, it is not uncommon for AGEs to provide different and sometimes conflicting predictions. Combining multiple AGEs might allow for more accurate predictions. Here we analyzed the ab initio open reading frame (ORF calling performance of different AGEs based on curated genome annotations of eight strains from different bacterial species with GC% ranging from 35-52%. We present a case study which demonstrates a novel way of comparative genome annotation, using combinations of AGEs in a pre-defined order (or path to predict ORF start codons. The order of AGE combinations is from high to low specificity, where the specificity is based on the eight genome annotations. For each AGE combination we are able to derive a so-called projected confidence value, which is the average specificity of ORF start codon prediction based on the eight genomes. The projected confidence enables estimating likeliness of a correct prediction for a particular ORF start codon by a particular AGE combination, pinpointing ORFs notoriously difficult to predict start codons. We correctly predict start codons for 90.5±4.8% of the genes in a genome (based on the eight genomes with an accuracy of 81.1±7.6%. Our consensus-path methodology allows a marked improvement over majority voting (9.7±4.4% and with an optimal path ORF start prediction sensitivity is gained while maintaining a high specificity.

Time optimal paths for high speed maneuvering

Energy Technology Data Exchange (ETDEWEB)

Reister, D.B.; Lenhart, S.M.

1993-01-01

Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

Cooperative organic mine avoidance path planning

Science.gov (United States)

McCubbin, Christopher B.; Piatko, Christine D.; Peterson, Adam V.; Donnald, Creighton R.; Cohen, David

2005-06-01

The JHU/APL Path Planning team has developed path planning techniques to look for paths that balance the utility and risk associated with different routes through a minefield. Extending on previous years' efforts, we investigated real-world Naval mine avoidance requirements and developed a tactical decision aid (TDA) that satisfies those requirements. APL has developed new mine path planning techniques using graph based and genetic algorithms which quickly produce near-minimum risk paths for complicated fitness functions incorporating risk, path length, ship kinematics, and naval doctrine. The TDA user interface, a Java Swing application that obtains data via Corba interfaces to path planning databases, allows the operator to explore a fusion of historic and in situ mine field data, control the path planner, and display the planning results. To provide a context for the minefield data, the user interface also renders data from the Digital Nautical Chart database, a database created by the National Geospatial-Intelligence Agency containing charts of the world's ports and coastal regions. This TDA has been developed in conjunction with the COMID (Cooperative Organic Mine Defense) system. This paper presents a description of the algorithms, architecture, and application produced.

ITS Multi-path Communications Access Decision Scheme

Directory of Open Access Journals (Sweden)

Miroslav Svitek

2008-02-01

Full Text Available Intelligent Transport Systems (ITS require widely spread and guarantied quality communications services. Method of ITS decomposition to set of subsystems and quantification of communications subsystems parameters is introduced. Due to typical complexity of the IST solution and mobility as the typical system elements property idea of communications systems with multipath multivendor structures is adopted. Resolution of seamless switching within a set of available wireless access solutions is presented. CALM based system or specifically designed and configured L3/L2 switching can be relevant solution for multi-path access communication system. These systems meet requirements of the seamless secure communications functionality within even extensive cluster of moving objects. Competent decision processes based on precisely quantified system requirements and each performance indicator tolerance range must be implemented to keep service up and running with no influence of continuously changing conditions in time and served space. Method of different paths service quality evaluation and selection of the best possible active communications access path is introduced. Proposed approach is based on Kalman filtering, which separates reasonable part of noise and also allows prediction of the individual parameters near future behavior. Presented classification algorithm applied on filtered measured data combined with deterministic parameters is trained using training data, i.e. combination of parameters vectors line and relevant decisions. Quality of classification is dependent on the size and quality of the training sets. This method is studied within projects e-Ident, DOTEK and SRATVU which are elaborating results of project CAMNA.

An Efficient Energy Constraint Based UAV Path Planning for Search and Coverage

Directory of Open Access Journals (Sweden)

German Gramajo

2017-01-01

Full Text Available A path planning strategy for a search and coverage mission for a small UAV that maximizes the area covered based on stored energy and maneuverability constraints is presented. The proposed formulation has a high level of autonomy, without requiring an exact choice of optimization parameters, and is appropriate for real-time implementation. The computed trajectory maximizes spatial coverage while closely satisfying terminal constraints on the position of the vehicle and minimizing the time of flight. Comparisons of this formulation to a path planning algorithm based on those with time constraint show equivalent coverage performance but improvement in prediction of overall mission duration and accuracy of the terminal position of the vehicle.

Accurate prediction of the functional significance of single nucleotide polymorphisms and mutations in the ABCA1 gene.

Directory of Open Access Journals (Sweden)

Liam R Brunham

2005-12-01

Full Text Available The human genome contains an estimated 100,000 to 300,000 DNA variants that alter an amino acid in an encoded protein. However, our ability to predict which of these variants are functionally significant is limited. We used a bioinformatics approach to define the functional significance of genetic variation in the ABCA1 gene, a cholesterol transporter crucial for the metabolism of high density lipoprotein cholesterol. To predict the functional consequence of each coding single nucleotide polymorphism and mutation in this gene, we calculated a substitution position-specific evolutionary conservation score for each variant, which considers site-specific variation among evolutionarily related proteins. To test the bioinformatics predictions experimentally, we evaluated the biochemical consequence of these sequence variants by examining the ability of cell lines stably transfected with the ABCA1 alleles to elicit cholesterol efflux. Our bioinformatics approach correctly predicted the functional impact of greater than 94% of the naturally occurring variants we assessed. The bioinformatics predictions were significantly correlated with the degree of functional impairment of ABCA1 mutations (r2 = 0.62, p = 0.0008. These results have allowed us to define the impact of genetic variation on ABCA1 function and to suggest that the in silico evolutionary approach we used may be a useful tool in general for predicting the effects of DNA variation on gene function. In addition, our data suggest that considering patterns of positive selection, along with patterns of negative selection such as evolutionary conservation, may improve our ability to predict the functional effects of amino acid variation.

Cyclic fatigue resistance of R-Pilot, HyFlex EDM and PathFile nickel-titanium glide path files in artificial canals with double (S-shaped) curvature.

Science.gov (United States)

Uslu, G; Özyürek, T; Yılmaz, K; Gündoğar, M

2018-05-01

To examine the cyclic fatigue resistances of R-Pilot, HyFlex EDM and PathFile NiTi glide path files in S-shaped artificial canals. Twenty R-Pilot (12.5/.04), 20 HyFlex EDM (10/.05) and 20 PathFile (19/.02) single-file glide path files were included. Sixty files (n: 20/each) were subjected to static cyclic fatigue testing using double-curved canals until fracture occurred (TF). The number of cycles to fracture (NCF) was calculated by multiplying the rpm value by the TF. The length of the fractured fragment (FL) was determined by a digital microcaliper. Six samples of fractured files (n: 2/each) were examined by SEM to determine the fracture mode. The NCF and the FL data were analysed using one-way anova, post hoc Tamhane and Kruskal-Wallis tests using SPPS 21 software. The significance level was set at 5%. In the double-curved canal, all the files fractured first in the apical curvature and then in the coronal curvature. The NCF values revealed that the R-Pilot had the greatest cyclic fatigue resistance, followed by the HyFlex EDM and PathFile in both the apical and coronal curvatures (P < 0.05). R-Pilot NiTi glide path files, used in a reciprocating motion, had the greatest cyclic fatigue resistance amongst the tested NiTi glide path files in an artificial S-shaped canal. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

The effect of solar and lunar currents on simultaneous phase path, group path and amplitude measurements

International Nuclear Information System (INIS)

Baulch, R.N.E.; Butcher, E.C.

1984-01-01

The solar and lunar variations in the phase path, group path and amplitude of a fixed frequency transmission were obtained at the September equinox over a slightly oblique path. The phase of the lunar semi-diurnal tide in the phase path and amplitude were similar, the maxima occurring near 0200 lunar time, whereas the group path had a maximum near 0800 lunar time. These results were compared with other results obtained near the same location. The results suggest a complex situation in the E-region, where the height of the lunar current depends on season, and also suggest that the location and distribution of the solar and lunar currents may be different. (author)

Spatio-temporal structure, path characteristics and perceptual grouping in immediate serial spatial recall

Directory of Open Access Journals (Sweden)

Carlo De Lillo

2016-11-01

Full Text Available Immediate serial spatial recall measures the ability to retain sequences of locations in short-term memory and is considered the spatial equivalent of digit span. It is tested by requiring participants to reproduce sequences of movements performed by an experimenter or displayed on a monitor. Different organizational factors dramatically affect serial spatial recall but they are often confounded or underspecified. Untangling them is crucial for the characterization of working-memory models and for establishing the contribution of structure and memory capacity to spatial span. We report five experiments assessing the relative role and independence of factors that have been reported in the literature. Experiment 1 disentangled the effects of spatial clustering and path-length by manipulating the distance of items displayed on a touchscreen monitor. Long-path sequences segregated by spatial clusters were compared with short-path sequences not segregated by clusters. Recall was more accurate for sequences segregated by clusters independently from path-length. Experiment 2 featured conditions where temporal pauses were introduced between or within cluster boundaries during the presentation of sequences with the same paths. Thus, the temporal structure of the sequences was either consistent or inconsistent with a hierarchical representation based on segmentation by spatial clusters but the effect of structure could not be confounded with effects of path-characteristics. Pauses at cluster boundaries yielded more accurate recall, as predicted by a hierarchical model. In Experiment 3, the systematic manipulation of sequence structure, path-length and presence of path-crossings of sequences showed that structure explained most of the variance, followed by the presence/absence of path-crossings, and path-length. Experiments 4 and 5 replicated the results of the previous experiments in immersive virtual reality navigation tasks where the viewpoint of the

On the structure of path-like trees

OpenAIRE

Muntaner Batle, Francesc Antoni; Rius Font, Miquel

2007-01-01

We study the structure of path-like trees. In order to do this, we introduce a set of trees that we call expandable trees. In this paper we also generalize the concept of path-like trees and we call such generalization generalized path-like trees. As in the case of path-like trees, generalized path-like trees, have very nice labeling properties.

Paths from socioemotional behavior in middle childhood to personality in middle adulthood.

Science.gov (United States)

Pulkkinen, Lea; Kokko, Katja; Rantanen, Johanna

2012-09-01

Continuity in individual differences from socioemotional behavior in middle childhood to personality characteristics in middle adulthood was examined on the assumption that they share certain temperament-related elements. Socioemotional characteristics were measured using teacher ratings at ages 8 (N = 369; 53% males) and 14 (95% of the initial sample). Personality was assessed at age 42 (63% of the initial sample; 50% males) using a shortened version of the NEO Personality Inventory (NEO-PI); the Karolinska Scales of Personality (KSP); and the Adult Temperament Questionnaire (ATQ). Three models were tested using structural equation modeling. The results confirmed paths (a) from behavioral activity to adult Extraversion and Openness (NEO-PI), sociability (KSP), and surgency (ATQ); (b) from well-controlled behavior to adult conformity (KSP) and Conscientiousness (NEO-PI); and (c) from negative emotionality to adult aggression (KSP). The paths were significant only for one gender, and more frequently for males than for females. The significant male paths from behavioral activity to all indicators of adult activity and from well-controlled behavior to adult conformity started at age 8, whereas significant female paths from behavioral activity to adult sociability and from well-controlled behavior to adult Conscientiousness started at age 14. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Differential equations driven by rough paths with jumps

Science.gov (United States)

Friz, Peter K.; Zhang, Huilin

2018-05-01

We develop the rough path counterpart of Itô stochastic integration and differential equations driven by general semimartingales. This significantly enlarges the classes of (Itô/forward) stochastic differential equations treatable with pathwise methods. A number of applications are discussed.

Improved Geothermometry Through Multivariate Reaction-path Modeling and Evaluation of Geomicrobiological Influences on Geochemical Temperature Indicators: Final Report

Energy Technology Data Exchange (ETDEWEB)

Mattson, Earl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fujita, Yoshiko [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Carl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Reed, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Vicki [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-03-01

The project was aimed at demonstrating that the geothermometric predictions can be improved through the application of multi-element reaction path modeling that accounts for lithologic and tectonic settings, while also accounting for biological influences on geochemical temperature indicators. The limited utilization of chemical signatures by individual traditional geothermometer in the development of reservoir temperature estimates may have been constraining their reliability for evaluation of potential geothermal resources. This project, however, was intended to build a geothermometry tool which can integrate multi-component reaction path modeling with process-optimization capability that can be applied to dilute, low-temperature water samples to consistently predict reservoir temperature within ±30 °C. The project was also intended to evaluate the extent to which microbiological processes can modulate the geochemical signals in some thermal waters and influence the geothermometric predictions.

Controlling the optical path length in turbid media using differential path-length spectroscopy: fiber diameter dependence

NARCIS (Netherlands)

Kaspers, O. P.; Sterenborg, H. J. C. M.; Amelink, A.

2008-01-01

We have characterized the path length for the differential path-length spectroscopy (DPS) fiber optic geometry for a wide range of optical properties and for fiber diameters ranging from 200 mu m to 1000 mu m. Phantom measurements show that the path length is nearly constant for scattering

Air Pollution alongside Bike-Paths in Bogota - Colombia

Directory of Open Access Journals (Sweden)

Juan Felipe Franco

2016-11-01

Full Text Available The study we present in this paper aims at characterizing the range of fine particulate matter (PM2.5 and black carbon (BC concentrations to which bike-path users in Bogotá are exposed to. Using a bike equipped with a DustTrak and a micro-aethalometer we measured PM2.5 and BC concentration levels along bike-paths corridors, during weekdays and weekends. Experiments were conducted in fours streets, representing four typical configurations of bike-paths in the city. Traffic data for workdays was also available from local mobility authority. Results indicate that bike-paths users in Bogota are exposed to air pollution levels far exceeding the threshold values established as potentially dangerous for human health. Average concentrations for PM2.5 ranged between 80 and 136 ug/m3 in workdays and between 30 and 72 ug/m3 in weekends. BC mean concentrations were between 16 and 38 µg/m3 during workdays and in the range 10 to 32 µg/m3 during weekends. A statistically significant difference exists in the levels of pollutants concentrations measured during workdays and weekends for all the considered bike paths. According to our results, both traffic volume and diffusions conditions, which are affected by many factors including street geometry, affect bike-path user’s exposure levels. Taking into account the important role that bicycling is playing as an alternative transport mode in Latin American cities, we consider these results provide useful insights to increase the appreciation of the excessive bikers´ exposure to air pollution in Bogotá. Moreover, these findings contribute with technical elements that should lead to the inclusion of air quality variable when designing and planning sustainable urban mobility infrastructures.

ComPath: comparative enzyme analysis and annotation in pathway/subsystem contexts

Directory of Open Access Journals (Sweden)

Kim Sun

2008-03-01

Full Text Available Abstract Background Once a new genome is sequenced, one of the important questions is to determine the presence and absence of biological pathways. Analysis of biological pathways in a genome is a complicated task since a number of biological entities are involved in pathways and biological pathways in different organisms are not identical. Computational pathway identification and analysis thus involves a number of computational tools and databases and typically done in comparison with pathways in other organisms. This computational requirement is much beyond the capability of biologists, so information systems for reconstructing, annotating, and analyzing biological pathways are much needed. We introduce a new comparative pathway analysis workbench, ComPath, which integrates various resources and computational tools using an interactive spreadsheet-style web interface for reliable pathway analyses. Results ComPath allows users to compare biological pathways in multiple genomes using a spreadsheet style web interface where various sequence-based analysis can be performed either to compare enzymes (e.g. sequence clustering and pathways (e.g. pathway hole identification, to search a genome for de novo prediction of enzymes, or to annotate a genome in comparison with reference genomes of choice. To fill in pathway holes or make de novo enzyme predictions, multiple computational methods such as FASTA, Whole-HMM, CSR-HMM (a method of our own introduced in this paper, and PDB-domain search are integrated in ComPath. Our experiments show that FASTA and CSR-HMM search methods generally outperform Whole-HMM and PDB-domain search methods in terms of sensitivity, but FASTA search performs poorly in terms of specificity, detecting more false positive as E-value cutoff increases. Overall, CSR-HMM search method performs best in terms of both sensitivity and specificity. Gene neighborhood and pathway neighborhood (global network visualization tools can be used

Feynman path integral application on deriving black-scholes diffusion equation for european option pricing

International Nuclear Information System (INIS)

Utama, Briandhika; Purqon, Acep

2016-01-01

Path Integral is a method to transform a function from its initial condition to final condition through multiplying its initial condition with the transition probability function, known as propagator. At the early development, several studies focused to apply this method for solving problems only in Quantum Mechanics. Nevertheless, Path Integral could also apply to other subjects with some modifications in the propagator function. In this study, we investigate the application of Path Integral method in financial derivatives, stock options. Black-Scholes Model (Nobel 1997) was a beginning anchor in Option Pricing study. Though this model did not successfully predict option price perfectly, especially because its sensitivity for the major changing on market, Black-Scholes Model still is a legitimate equation in pricing an option. The derivation of Black-Scholes has a high difficulty level because it is a stochastic partial differential equation. Black-Scholes equation has a similar principle with Path Integral, where in Black-Scholes the share's initial price is transformed to its final price. The Black-Scholes propagator function then derived by introducing a modified Lagrange based on Black-Scholes equation. Furthermore, we study the correlation between path integral analytical solution and Monte-Carlo numeric solution to find the similarity between this two methods. (paper)

KINEMATIC ANALYSES OF THE GOLF SWING HUB PATH AND ITS ROLE IN GOLFER/CLUB KINETIC TRANSFERS

Directory of Open Access Journals (Sweden)

Steven M. Nesbit

2009-06-01

Full Text Available This study analyzed the fundamental geometric and kinematic characteristics of the swing hub path of the golf shot for four diverse subjects. In addition, the role of the hub path geometry in transferring the kinetic quantities from the golfer to the club were investigated. The hub path was found to have a complex geometry with significantly changing radii, and a constantly moving center-of-curvature during the downswing for all subjects. While the size and shape of the hub path differed considerably among the subjects, a three phase radius-based pattern was revealed that aligned with distinct stages of the downswing. Artificially controlling and optimizing the hub path of the better golfer in the group indicated that a non-circular hub path was superior to a constant radius path in minimizing the kinetic loading while generating the highest possible club head velocity. The shape and purpose of the hub path geometry appears to result from a complex combination of achieving equilibrium between the golfer and the club, and a purposeful configuring of the path to control the outward movement of the club while minimizing the kinetic loading on the golfer yet transferring the maximum kinetic quantities to the club. Describing the downswing relative to the hub path phasing is presented and was found to be informative since the phases align with significant swing, kinetic and kinematic markers. These findings challenge golf swing modeling methodologies which fix the center-of-curvature of the hub path thus constraining it to constant radius motion

Comparison of Estimation Techniques for Vibro-Acoustic Transfer Path Analysis

Directory of Open Access Journals (Sweden)

Paulo Eduardo França Padilha

2006-01-01

Full Text Available Vibro-acoustic Transfer Path Analysis (TPA is a tool to evaluate the contribution of different energy propagation paths between a source and a receiver, linked to each other by a number of connections. TPA is typically used to quantify and rank the relative importance of these paths in a given frequency band, determining the most significant one to the receiver. Basically, two quantities have to be determined for TPA: the operational forces at each transfer path and the Frequency Response Functions (FRF of these paths. The FRF are obtained either experimentally or analytically, and the influence of the mechanical impedance of the source can be taken into account or not. The operational forces can be directly obtained from measurements using force transducers or indirectly estimated from auxiliary response measurements. Two methods to obtain the operational forces indirectly – the Complex Stiffness Method (CSM and the Matrix Inversion Method (MIM – associated with two possible configurations to determine the FRF – including and excluding the source impedance – are presented and discussed in this paper. The effect of weak and strong coupling among the paths is also commented considering the techniques previously presented. The main conclusion is that, with the source removed, CSM gives more accurate results. On the other hand, with the source present, MIM is preferable. In the latter case, CSM should be used only if there is a high impedance mismatch between the source and the receiver. Both methods are not affected by a higher or lower degree of coupling among the transfer paths.

Using wind tunnels to predict bird mortality in wind farms: the case of griffon vultures.

Directory of Open Access Journals (Sweden)

Manuela de Lucas

Full Text Available BACKGROUND: Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. METHODOLOGY/PRINCIPAL FINDINGS: As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topography and wind flows in relation to flight paths of griffon vultures, using a scaled model of the wind farm area in an aerodynamic wind tunnel, and test the difference between the observed flight paths of griffon vultures and the predominant wind flows. Different wind currents for each wind direction in the aerodynamic model were observed. Simulations of wind flows in a wind tunnel were compared with observed flight paths of griffon vultures. No statistical differences were detected between the observed flight trajectories of griffon vultures and the wind passages observed in our wind tunnel model. A significant correlation was found between dead vultures predicted proportion of vultures crossing those cells according to the aerodynamic model. CONCLUSIONS: Griffon vulture flight routes matched the predominant wind flows in the area (i.e. they followed the routes where less flight effort was needed. We suggest using these kinds of simulations to predict flight paths over complex terrains can inform the location of wind turbines and thereby reduce soaring bird mortality.

Walking path-planning method for multiple radiation areas

International Nuclear Information System (INIS)

Liu, Yong-kuo; Li, Meng-kun; Peng, Min-jun; Xie, Chun-li; Yuan, Cheng-qian; Wang, Shuang-yu; Chao, Nan

2016-01-01

Highlights: • Radiation environment modeling method is designed. • Path-evaluating method and segmented path-planning method are proposed. • Path-planning simulation platform for radiation environment is built. • The method avoids to be misled by minimum dose path in single area. - Abstract: Based on minimum dose path-searching method, walking path-planning method for multiple radiation areas was designed to solve minimum dose path problem in single area and find minimum dose path in the whole space in this paper. Path-planning simulation platform was built using C# programming language and DirectX engine. The simulation platform was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method is effective in providing safety for people walking in nuclear facilities.

Does gender moderate the subjective measurement and structural paths in behavioural and cognitive aspects of gambling disorder in treatment-seeking adults?

Science.gov (United States)

Smith, David; Battersby, Malcolm; Harvey, Peter

2015-09-01

Gender differences have been observed in the pathogenesis of gambling disorder and gambling related urge and cognitions are predictive of relapse to problem gambling. A better understanding of these mechanisms concurrently may help in the development of more directed therapies. We evaluated gender effects on behavioural and cognitive paths to gambling disorder from self-report data. Participants (N=454) were treatment-seeking problem gamblers on first presentation to a gambling therapy service between January 2012 and December 2014. We firstly investigated if aspects of gambling related urge, cognitions (interpretive bias and gambling expectancies) and gambling severity were more central to men than women. Subsequently, a full structural equation model tested if gender moderated behavioural and cognitive paths to gambling severity. Men (n=280, mean age=37.4years, SD=11.4) were significantly younger than women (n=174, mean age=48.7years, SD=12.9) (pgambling severity, gambling related urge, interpretive bias and gambling expectancies. The paths for urge to gambling severity and interpretive bias to gambling severity were stronger for men than women and statistically significant (pgambling expectancies to gambling severity were insignificant for both men and women. This study detected an important signal in terms of theoretical mechanisms to explaining gambling disorder and gender differences. It has implications for treatment development including relapse prevention. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cooperative path planning of unmanned aerial vehicles

CERN Document Server

Tsourdos, Antonios; Shanmugavel, Madhavan

2010-01-01

An invaluable addition to the literature on UAV guidance and cooperative control, Cooperative Path Planning of Unmanned Aerial Vehicles is a dedicated, practical guide to computational path planning for UAVs. One of the key issues facing future development of UAVs is path planning: it is vital that swarm UAVs/ MAVs can cooperate together in a coordinated manner, obeying a pre-planned course but able to react to their environment by communicating and cooperating. An optimized path is necessary in order to ensure a UAV completes its mission efficiently, safely, and successfully. Focussing on the path planning of multiple UAVs for simultaneous arrival on target, Cooperative Path Planning of Unmanned Aerial Vehicles also offers coverage of path planners that are applicable to land, sea, or space-borne vehicles. Cooperative Path Planning of Unmanned Aerial Vehicles is authored by leading researchers from Cranfield University and provides an authoritative resource for researchers, academics and engineers working in...

Neck Muscle Moment Arms Obtained In-Vivo from MRI: Effect of Curved and Straight Modeled Paths.

Science.gov (United States)

Suderman, Bethany L; Vasavada, Anita N

2017-08-01

Musculoskeletal models of the cervical spine commonly represent neck muscles with straight paths. However, straight lines do not best represent the natural curvature of muscle paths in the neck, because the paths are constrained by bone and soft tissue. The purpose of this study was to estimate moment arms of curved and straight neck muscle paths using different moment arm calculation methods: tendon excursion, geometric, and effective torque. Curved and straight muscle paths were defined for two subject-specific cervical spine models derived from in vivo magnetic resonance images (MRI). Modeling neck muscle paths with curvature provides significantly different moment arm estimates than straight paths for 10 of 15 neck muscles (p straight lines to model muscle paths can lead to overestimating neck extension moment. However, moment arm methods for curved paths should be investigated further, as different methods of calculating moment arm can provide different estimates.

Novel Methods for Drug-Target Interaction Prediction using Graph Mining

KAUST Repository

Ba Alawi, Wail

2016-08-31

The problem of developing drugs that can be used to cure diseases is important and requires a careful approach. Since pursuing the wrong candidate drug for a particular disease could be very costly in terms of time and money, there is a strong interest in minimizing such risks. Drug repositioning has become a hot topic of research, as it helps reduce these risks significantly at the early stages of drug development by reusing an approved drug for the treatment of a different disease. Still, finding new usage for a drug is non-trivial, as it is necessary to find out strong supporting evidence that the proposed new uses of drugs are plausible. Many computational approaches were developed to narrow the list of possible candidate drug-target interactions (DTIs) before any experiments are done. However, many of these approaches suffer from unacceptable levels of false positives. We developed two novel methods based on graph mining networks of drugs and targets. The first method (DASPfind) finds all non-cyclic paths that connect a drug and a target, and using a function that we define, calculates a score from all the paths. This score describes our confidence that DTI is correct. We show that DASPfind significantly outperforms other state-of-the-art methods in predicting the top ranked target for each drug. We demonstrate the utility of DASPfind by predicting 15 novel DTIs over a set of ion channel proteins, and confirming 12 out of these 15 DTIs through experimental evidence reported in literature and online drug databases. The second method (DASPfind+) modifies DASPfind in order to increase the confidence and reliability of the resultant predictions. Based on the structure of the drug-target interaction (DTI) networks, we introduced an optimization scheme that incrementally alters the network structure locally for each drug to achieve more robust top 1 ranked predictions. Moreover, we explored effects of several similarity measures between the targets on the prediction

Gender Differences in Career Paths in Banking.

Science.gov (United States)

Morgan, Sandra; And Others

1993-01-01

Analyzed career paths of middle managers in bank. Study of matched pairs found that men (n=25) advanced faster and reached middle management through fewer promotions and positions than did women (n=25). Men had significantly more work experience outside of banking. In banking careers, men held more jobs in lending, whereas women occupied more…

Path-Goal Theory of Leadership

Science.gov (United States)

1975-04-01

Leadership and Turnover Among Managers ," Organization Behavior and Human Performance, 10(1973), pp. 184-200; R. J. House, "A Path-Goal Theory of...of Leadership ." 6R. J. House and G. Dessler, "Path-Goal Theory of Leadership " R. M. Stqg- dill. Managers , Employees, Organization (Ohio State...of Control." 23 R. J. House, "Notes on the Path-Goal Theory of Leadership " (University of Toronto, Faculty of Management Studies, May 1974). 24 R

Path integral in Snyder space

Energy Technology Data Exchange (ETDEWEB)

Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Štrajn, R. [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy)

2016-04-29

The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

Path integral in Snyder space

International Nuclear Information System (INIS)

Mignemi, S.; Štrajn, R.

2016-01-01

The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

Leavitt path algebras

CERN Document Server

Abrams, Gene; Siles Molina, Mercedes

2017-01-01

This book offers a comprehensive introduction by three of the leading experts in the field, collecting fundamental results and open problems in a single volume. Since Leavitt path algebras were first defined in 2005, interest in these algebras has grown substantially, with ring theorists as well as researchers working in graph C*-algebras, group theory and symbolic dynamics attracted to the topic. Providing a historical perspective on the subject, the authors review existing arguments, establish new results, and outline the major themes and ring-theoretic concepts, such as the ideal structure, Z-grading and the close link between Leavitt path algebras and graph C*-algebras. The book also presents key lines of current research, including the Algebraic Kirchberg Phillips Question, various additional classification questions, and connections to noncommutative algebraic geometry. Leavitt Path Algebras will appeal to graduate students and researchers working in the field and related areas, such as C*-algebras and...

Paths correlation matrix.

Science.gov (United States)

Qian, Weixian; Zhou, Xiaojun; Lu, Yingcheng; Xu, Jiang

2015-09-15

Both the Jones and Mueller matrices encounter difficulties when physically modeling mixed materials or rough surfaces due to the complexity of light-matter interactions. To address these issues, we derived a matrix called the paths correlation matrix (PCM), which is a probabilistic mixture of Jones matrices of every light propagation path. Because PCM is related to actual light propagation paths, it is well suited for physical modeling. Experiments were performed, and the reflection PCM of a mixture of polypropylene and graphite was measured. The PCM of the mixed sample was accurately decomposed into pure polypropylene's single reflection, pure graphite's single reflection, and depolarization caused by multiple reflections, which is consistent with the theoretical derivation. Reflection parameters of rough surface can be calculated from PCM decomposition, and the results fit well with the theoretical calculations provided by the Fresnel equations. These theoretical and experimental analyses verify that PCM is an efficient way to physically model light-matter interactions.

Techniques and applications of path integration

CERN Document Server

Schulman, L S

2005-01-01

A book of techniques and applications, this text defines the path integral and illustrates its uses by example. It is suitable for advanced undergraduates and graduate students in physics; its sole prerequisite is a first course in quantum mechanics. For applications requiring specialized knowledge, the author supplies background material.The first part of the book develops the techniques of path integration. Topics include probability amplitudes for paths and the correspondence limit for the path integral; vector potentials; the Ito integral and gauge transformations; free particle and quadra

Joint modeling of constrained path enumeration and path choice behavior: a semi-compensatory approach

DEFF Research Database (Denmark)

Kaplan, Sigal; Prato, Carlo Giacomo

2010-01-01

A behavioural and a modelling framework are proposed for representing route choice from a path set that satisfies travellers’ spatiotemporal constraints. Within the proposed framework, travellers’ master sets are constructed by path generation, consideration sets are delimited according to spatio...

Constraint-Based Local Search for Constrained Optimum Paths Problems

Science.gov (United States)

Pham, Quang Dung; Deville, Yves; van Hentenryck, Pascal

Constrained Optimum Path (COP) problems arise in many real-life applications and are ubiquitous in communication networks. They have been traditionally approached by dedicated algorithms, which are often hard to extend with side constraints and to apply widely. This paper proposes a constraint-based local search (CBLS) framework for COP applications, bringing the compositionality, reuse, and extensibility at the core of CBLS and CP systems. The modeling contribution is the ability to express compositional models for various COP applications at a high level of abstraction, while cleanly separating the model and the search procedure. The main technical contribution is a connected neighborhood based on rooted spanning trees to find high-quality solutions to COP problems. The framework, implemented in COMET, is applied to Resource Constrained Shortest Path (RCSP) problems (with and without side constraints) and to the edge-disjoint paths problem (EDP). Computational results show the potential significance of the approach.

Stability of Intelligent Transportation Network Dynamics: A Daily Path Flow Adjustment considering Travel Time Differentiation

Directory of Open Access Journals (Sweden)

Ming-Chorng Hwang

2015-01-01

Full Text Available A theoretic formulation on how traffic time information distributed by ITS operations influences the trajectory of network flows is presented in this paper. The interactions between users and ITS operator are decomposed into three parts: (i travel time induced path flow dynamics (PFDTT; (ii demand induced path flow dynamics (PFDD; and (iii predicted travel time dynamics for an origin-destination (OD pair (PTTDOD. PFDTT describes the collective results of user’s daily route selection by pairwise comparison of path travel time provided by ITS services. The other two components, PTTDOD and PFDD, are concentrated on the evolutions of system variables which are predicted and observed, respectively, by ITS operators to act as a benchmark in guiding the target system towards an expected status faster. In addition to the delivered modelings, the stability theorem of the equilibrium solution in the sense of Lyapunov stability is also provided. A Lyapunov function is developed and employed to the proof of stability theorem to show the asymptotic behavior of the aimed system. The information of network flow dynamics plays a key role in traffic control policy-making. The evaluation of ITS-based strategies will not be reasonable without a well-established modeling of network flow evolutions.

Forecasting Significant Societal Events Using The Embers Streaming Predictive Analytics System.

Science.gov (United States)

Doyle, Andy; Katz, Graham; Summers, Kristen; Ackermann, Chris; Zavorin, Ilya; Lim, Zunsik; Muthiah, Sathappan; Butler, Patrick; Self, Nathan; Zhao, Liang; Lu, Chang-Tien; Khandpur, Rupinder Paul; Fayed, Youssef; Ramakrishnan, Naren

2014-12-01

Developed under the Intelligence Advanced Research Project Activity Open Source Indicators program, Early Model Based Event Recognition using Surrogates (EMBERS) is a large-scale big data analytics system for forecasting significant societal events, such as civil unrest events on the basis of continuous, automated analysis of large volumes of publicly available data. It has been operational since November 2012 and delivers approximately 50 predictions each day for countries of Latin America. EMBERS is built on a streaming, scalable, loosely coupled, shared-nothing architecture using ZeroMQ as its messaging backbone and JSON as its wire data format. It is deployed on Amazon Web Services using an entirely automated deployment process. We describe the architecture of the system, some of the design tradeoffs encountered during development, and specifics of the machine learning models underlying EMBERS. We also present a detailed prospective evaluation of EMBERS in forecasting significant societal events in the past 2 years.

Isomorphisms and traversability of directed path graphs

NARCIS (Netherlands)

Broersma, Haitze J.; Li, Xueliang; Li, X.

1998-01-01

The concept of a line digraph is generalized to that of a directed path graph. The directed path graph $\\forw P_k(D)$ of a digraph $D$ is obtained by representing the directed paths on $k$ vertices of $D$ by vertices. Two vertices are joined by an arc whenever the corresponding directed paths in $D$

PATH ANALYSIS OF RECORDING SYSTEM INNOVATION FACTORS AFFECTING ADOPTION OF GOAT FARMERS

Directory of Open Access Journals (Sweden)

S. Okkyla

2014-09-01

Full Text Available The objective of this study was to evaluate the path analysis of recording system innovation factorsaffecting adoption of goat farmers. This study was conducted from January to February 2014 inPringapus District, Semarang Regency by using survey method. For determining the location, this studyused purposive sampling method. The amount of respondents were determined by quota samplingmethod. Total respondents randomly chosed were 146 farmers. The data were descriptively andquantitatively analyzed by using path analysis of statistical package for the social science (SPSS 16.Independent variables in this study were internal factor, motivation, innovation characteristics,information source, and dependent variable was adoption. Analysis of linear regression showed thatthere was no significant effect of internal factor on adoption, so that it was important to use the trimmingmethod in path analysis. The result of path analysis showed that the influence of motivation, innovationcharacteristics and information source on adoption were 0.168; 0.720 and 0.09, respectively. Innovationcharacteristics were the greatest effect on adoption. In conclusion, by improving innovationcharacteristics of respondent through motivation and information source may significantly increase theadoption of recording system in goat farmers.

Computed micro-tomographic evaluation of glide path with nickel-titanium rotary PathFile in maxillary first molars curved canals.

Science.gov (United States)

Pasqualini, Damiano; Bianchi, Caterina Chiara; Paolino, Davide Salvatore; Mancini, Lucia; Cemenasco, Andrea; Cantatore, Giuseppe; Castellucci, Arnaldo; Berutti, Elio

2012-03-01

X-ray computed micro-tomography scanning allows high-resolution 3-dimensional imaging of small objects. In this study, micro-CT scanning was used to compare the ability of manual and mechanical glide path to maintain the original root canal anatomy. Eight extracted upper first permanent molars were scanned at the TOMOLAB station at ELETTRA Synchrotron Light Laboratory in Trieste, Italy, with a microfocus cone-beam geometry system. A total of 2,400 projections on 360° have been acquired at 100 kV and 80 μA, with a focal spot size of 8 μm. Buccal root canals of each specimen (n = 16) were randomly assigned to PathFile (P) or stainless-steel K-file (K) to perform glide path at the full working length. Specimens were then microscanned at the apical level (A) and at the point of the maximum curvature level (C) for post-treatment analyses. Curvatures of root canals were classified as moderate (≤35°) or severe (≥40°). The ratio of diameter ratios (RDRs) and the ratio of cross-sectional areas (RAs) were assessed. For each level of analysis (A and C), 2 balanced 2-way factorial analyses of variance (P < .05) were performed to evaluate the significance of the instrument factor and of canal curvature factor as well as the interactions of the factors both with RDRs and RAs. Specimens in the K group had a mean curvature of 35.4° ± 11.5°; those in the P group had a curvature of 38° ± 9.9°. The instrument factor (P and K) was extremely significant (P < .001) for both the RDR and RA parameters, regardless of the point of analysis. Micro-CT scanning confirmed that NiTi rotary PathFile instruments preserve the original canal anatomy and cause less canal aberrations. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Promoting Social and Emotional Competencies among Young Children in Croatia with Preschool PATHS.

Directory of Open Access Journals (Sweden)

Josipa Mihic

2016-11-01

Full Text Available Preschool PATHS (Promoting Alternative Thinking Strategies is an evidence-based universal prevention program focused on promoting children’s social and emotional competencies and reducing the likelihood of behaviour problems and negative relationships with peers and teachers. This paper examines changes in the social and emotional competencies of the first children to participate in Preschool PATHS in Croatia. This study included 164 children, ages 3-6, in 12 preschool classrooms in three cities across Croatia, who participated in the classroom-based Preschool PATHS curriculum. At the beginning and end of the preschool year, teachers completed wellvalidated and reliable assessments of social and emotional competencies on each child. Hierarchical linear models revealed statistically significant and substantial improvements in prosocial behaviour, emotion regulation, emotion symptoms, peer problems, relational aggression, conduct problems, and hyperactive-impulsive behaviour. Study findings reveal significant changes in children’s social and emotional competencies during preschool. This time may present a unique opportunity to buttress children’s skills and improve long-term school success through the implementation of a rigorous empiricallyvalidated prevention program such as Preschool PATHS.

Surface tensions of multi-component mixed inorganic/organic aqueous systems of atmospheric significance: measurements, model predictions and importance for cloud activation predictions

Directory of Open Access Journals (Sweden)

D. O. Topping

2007-01-01

Full Text Available In order to predict the physical properties of aerosol particles, it is necessary to adequately capture the behaviour of the ubiquitous complex organic components. One of the key properties which may affect this behaviour is the contribution of the organic components to the surface tension of aqueous particles in the moist atmosphere. Whilst the qualitative effect of organic compounds on solution surface tensions has been widely reported, our quantitative understanding on mixed organic and mixed inorganic/organic systems is limited. Furthermore, it is unclear whether models that exist in the literature can reproduce the surface tension variability for binary and higher order multi-component organic and mixed inorganic/organic systems of atmospheric significance. The current study aims to resolve both issues to some extent. Surface tensions of single and multiple solute aqueous solutions were measured and compared with predictions from a number of model treatments. On comparison with binary organic systems, two predictive models found in the literature provided a range of values resulting from sensitivity to calculations of pure component surface tensions. Results indicate that a fitted model can capture the variability of the measured data very well, producing the lowest average percentage deviation for all compounds studied. The performance of the other models varies with compound and choice of model parameters. The behaviour of ternary mixed inorganic/organic systems was unreliably captured by using a predictive scheme and this was dependent on the composition of the solutes present. For more atmospherically representative higher order systems, entirely predictive schemes performed poorly. It was found that use of the binary data in a relatively simple mixing rule, or modification of an existing thermodynamic model with parameters derived from binary data, was able to accurately capture the surface tension variation with concentration. Thus

Path analysis of risk factors leading to premature birth.

Science.gov (United States)

Fields, S J; Livshits, G; Sirotta, L; Merlob, P

1996-01-01

The present study tested whether various sociodemographic, anthropometric, behavioral, and medical/physiological factors act in a direct or indirect manner on the risk of prematurity using path analysis on a sample of Israeli births. The path model shows that medical complications, primarily toxemia, chorioammionitis, and a previous low birth weight delivery directly and significantly act on the risk of prematurity as do low maternal pregnancy weight gain and ethnicity. Other medical complications, including chronic hypertension, preclampsia, and placental abruption, although significantly correlated with prematurity, act indirectly on prematurity through toxemia. The model further shows that the commonly accepted sociodemographic, anthropometric, and behavioral risk factors act by modifying the development of medical complications that lead to prematurity as opposed to having a direct effect on premature delivery. © 1996 Wiley-Liss, Inc. Copyright © 1996 Wiley-Liss, Inc.

Facial emotion recognition, face scan paths, and face perception in children with neurofibromatosis type 1.

Science.gov (United States)

Lewis, Amelia K; Porter, Melanie A; Williams, Tracey A; Bzishvili, Samantha; North, Kathryn N; Payne, Jonathan M

2017-05-01

This study aimed to investigate face scan paths and face perception abilities in children with Neurofibromatosis Type 1 (NF1) and how these might relate to emotion recognition abilities in this population. The authors investigated facial emotion recognition, face scan paths, and face perception in 29 children with NF1 compared to 29 chronological age-matched typically developing controls. Correlations between facial emotion recognition, face scan paths, and face perception in children with NF1 were examined. Children with NF1 displayed significantly poorer recognition of fearful expressions compared to controls, as well as a nonsignificant trend toward poorer recognition of anger. Although there was no significant difference between groups in time spent viewing individual core facial features (eyes, nose, mouth, and nonfeature regions), children with NF1 spent significantly less time than controls viewing the face as a whole. Children with NF1 also displayed significantly poorer face perception abilities than typically developing controls. Facial emotion recognition deficits were not significantly associated with aberrant face scan paths or face perception abilities in the NF1 group. These results suggest that impairments in the perception, identification, and interpretation of information from faces are important aspects of the social-cognitive phenotype of NF1. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Graphs with not all possible path-kernels

DEFF Research Database (Denmark)

Aldred, Robert; Thomassen, Carsten

2004-01-01

The Path Partition Conjecture states that the vertices of a graph G with longest path of length c may be partitioned into two parts X and Y such that the longest path in the subgraph of G induced by X has length at most a and the longest path in the subgraph of G induced by Y has length at most b...

Design of Active N-path Filters

NARCIS (Netherlands)

Darvishi, M.; van der Zee, Ronan A.R.; Nauta, Bram

2013-01-01

A design methodology for synthesis of active N-path bandpass filters is introduced. Based on this methodology, a 0.1-to-1.2 GHz tunable 6th-order N-path channel-select filter in 65 nm LP CMOS is introduced. It is based on coupling N-path filters with gyrators, achieving a “flat‿ passband shape and

Vapor nucleation paths in lyophobic nanopores.

Science.gov (United States)

Tinti, Antonio; Giacomello, Alberto; Casciola, Carlo Massimo

2018-04-19

In recent years, technologies revolving around the use of lyophobic nanopores gained considerable attention in both fundamental and applied research. Owing to the enormous internal surface area, heterogeneous lyophobic systems (HLS), constituted by a nanoporous lyophobic material and a non-wetting liquid, are promising candidates for the efficient storage or dissipation of mechanical energy. These diverse applications both rely on the forced intrusion and extrusion of the non-wetting liquid inside the pores; the behavior of HLS for storage or dissipation depends on the hysteresis between these two processes, which, in turn, are determined by the microscopic details of the system. It is easy to understand that molecular simulations provide an unmatched tool for understanding phenomena at these scales. In this contribution we use advanced atomistic simulation techniques in order to study the nucleation of vapor bubbles inside lyophobic mesopores. The use of the string method in collective variables allows us to overcome the computational challenges associated with the activated nature of the phenomenon, rendering a detailed picture of nucleation in confinement. In particular, this rare event method efficiently searches for the most probable nucleation path(s) in otherwise intractable, high-dimensional free-energy landscapes. Results reveal the existence of several independent nucleation paths associated with different free-energy barriers. In particular, there is a family of asymmetric transition paths, in which a bubble forms at one of the walls; the other family involves the formation of axisymmetric bubbles with an annulus shape. The computed free-energy profiles reveal that the asymmetric path is significantly more probable than the symmetric one, while the exact position where the asymmetric bubble forms is less relevant for the free energetics of the process. A comparison of the atomistic results with continuum models is also presented, showing how, for simple

Dynamic response characteristics of dual flow-path integrally bladed rotors

Science.gov (United States)

Beck, Joseph A.; Brown, Jeffrey M.; Scott-Emuakpor, Onome E.; Cross, Charles J.; Slater, Joseph C.

2015-02-01

New turbine engine designs requiring secondary flow compression often look to dual flow-path integrally bladed rotors (DFIBRs) since these stages have the ability to perform work on the secondary, or bypassed, flow-field. While analogous to traditional integrally bladed rotor stages, DFIBR designs have many differences that result in unique dynamic response characteristics that must be understood to avoid fatigue. This work investigates these characteristics using reduced-order models (ROMs) that incorporate mistuning through perturbations to blade frequencies. This work provides an alternative to computationally intensive geometric-mistuning approaches for DFIBRs by utilizing tuned blade mode reductions and substructure coupling in cyclic coordinates. Free and forced response results are compared to full finite element model (FEM) solutions to determine if any errors are related to the reduced-order model formulation reduction methods. It is shown that DFIBRs have many more frequency veering regions than their single flow-path integrally blade rotor (IBR) counterparts. Modal families are shown to transition between system, inner-blade, and outer-blade motion. Furthermore, findings illustrate that while mode localization of traditional IBRs is limited to a single or small subset of blades, DFIBRs can have modal energy localized to either an inner- or outer-blade set resulting in many blades responding above tuned levels. Lastly, ROM forced response predictions compare well to full FEM predictions for the two test cases shown.

Path integrals and geometry of trajectories

International Nuclear Information System (INIS)

Blau, M.; Keski-Vakkuri, E.; Niemi, A.J.

1990-01-01

A geometrical interpretation of path integrals is developed in the space of trajectories. This yields a supersymmetric formulation of a generic path integral, with the supersymmetry resembling the BRST supersymmetry of a first class constrained system. If the classical equation of motion is a Killing vector field in the space of trajectories, the supersymmetry localizes the path integral to classical trajectories and the WKB approximation becomes exact. This can be viewed as a path integral generalization of the Duistermaat-Heckman theorem, which states the conditions for the exactness of the WKB approximation for integrals in a compact phase space. (orig.)

A Path Model of School Violence Perpetration: Introducing Online Game Addiction as a New Risk Factor.

Science.gov (United States)

Kim, Jae Yop; Lee, Jeen Suk; Oh, Sehun

2015-08-10

Drawing on the cognitive information-processing model of aggression and the general aggression model, we explored why adolescents become addicted to online games and how their immersion in online games affects school violence perpetration (SVP). For this purpose, we conducted statistical analyses on 1,775 elementary and middle school students who resided in northern districts of Seoul, South Korea. The results validated the proposed structural equation model and confirmed the statistical significance of the structural paths from the variables; that is, the paths from child abuse and self-esteem to SVP were significant. The levels of self-esteem and child abuse victimization affected SVP, and this effect was mediated by online game addiction (OGA). Furthermore, a multigroup path analysis showed significant gender differences in the path coefficients of the proposed model, indicating that gender exerted differential effects on adolescents' OGA and SVP. Based on these results, prevention and intervention methods to curb violence in schools have been proposed. © The Author(s) 2015.

Perfect discretization of path integrals

International Nuclear Information System (INIS)

Steinhaus, Sebastian

2012-01-01

In order to obtain a well-defined path integral one often employs discretizations. In the case of General Relativity these generically break diffeomorphism symmetry, which has severe consequences since these symmetries determine the dynamics of the corresponding system. In this article we consider the path integral of reparametrization invariant systems as a toy example and present an improvement procedure for the discretized propagator. Fixed points and convergence of the procedure are discussed. Furthermore we show that a reparametrization invariant path integral implies discretization independence and acts as a projector onto physical states.

Perfect discretization of path integrals

Science.gov (United States)

Steinhaus, Sebastian

2012-05-01

In order to obtain a well-defined path integral one often employs discretizations. In the case of General Relativity these generically break diffeomorphism symmetry, which has severe consequences since these symmetries determine the dynamics of the corresponding system. In this article we consider the path integral of reparametrization invariant systems as a toy example and present an improvement procedure for the discretized propagator. Fixed points and convergence of the procedure are discussed. Furthermore we show that a reparametrization invariant path integral implies discretization independence and acts as a projector onto physical states.

An elasto-plastic self-consistent model with hardening based on dislocation density, twinning and de-twinning: Application to strain path changes in HCP metals

International Nuclear Information System (INIS)

Zecevic, Milovan; Knezevic, Marko; Beyerlein, Irene J.; Tomé, Carlos N.

2015-01-01

In this work, we develop a polycrystal mean-field constitutive model based on an elastic–plastic self-consistent (EPSC) framework. In this model, we incorporate recently developed subgrain models for dislocation density evolution with thermally activated slip, twin activation via statistical stress fluctuations, reoriented twin domains within the grain and associated stress relaxation, twin boundary hardening, and de-twinning. The model is applied to a systematic set of strain path change tests on pure beryllium (Be). Under the applied deformation conditions, Be deforms by multiple slip modes and deformation twinning and thereby provides a challenging test for model validation. With a single set of material parameters, determined using the flow-stress vs. strain responses during monotonic testing, the model predicts well the evolution of texture, lattice strains, and twinning. With further analysis, we demonstrate the significant influence of internal residual stresses on (1) the flow stress drop when reloading from one path to another, (2) deformation twin activation, (3) de-twinning during a reversal strain path change, and (4) the formation of additional twin variants during a cross-loading sequence. The model presented here can, in principle, be applied to other metals, deforming by multiple slip and twinning modes under a wide range of temperature, strain rate, and strain path conditions

Quantifying tight-gas sandstone permeability via critical path analysis

Science.gov (United States)

Rock permeability has been actively investigated over the past several decades by the geosciences community. However, its accurate estimation still presents significant technical challenges, especially in spatially complex rocks. In this letter, we apply critical path analysis (CPA) to estimate perm...

Path-separated electron interferometry in a scanning transmission electron microscope

Science.gov (United States)

Yasin, Fehmi S.; Harvey, Tyler R.; Chess, Jordan J.; Pierce, Jordan S.; McMorran, Benjamin J.

2018-05-01

We report a path-separated electron interferometer within a scanning transmission electron microscope. In this setup, we use a nanofabricated grating as an amplitude-division beamsplitter to prepare multiple spatially separated, coherent electron probe beams. We achieve path separations of 30 nm. We pass the  +1 diffraction order probe through amorphous carbon while passing the 0th and  ‑1 orders through vacuum. The probes are then made to interfere via imaging optics, and we observe an interference pattern at the CCD detector with up to 39.7% fringe visibility. We show preliminary experimental results in which the interference pattern was recorded during a 1D scan of the diffracted probes across a test phase object. These results qualitatively agree with a modeled interference predicted by an independent measurement of the specimen thickness. This experimental design can potentially be applied to phase contrast imaging and fundamental physics experiments, such as an exploration of electron wave packet coherence length.

On Hilbert space of paths

International Nuclear Information System (INIS)

Exner, P.; Kolerov, G.I.

1980-01-01

A Hilbert space of paths, the elements of which are determined by trigonometric series, was proposed and used recently by Truman. This space is shown to consist precisely of all absolutely continuous paths ending in the origin with square-integrable derivatives

Tool path in torus tool CNC machining

Directory of Open Access Journals (Sweden)

XU Ying

2016-10-01

Full Text Available This paper is about tool path in torus tool CNC machining.The mathematical model of torus tool is established.The tool path planning algorithm is determined through calculation of the cutter location,boundary discretization,calculation of adjacent tool path and so on,according to the conversion formula,the cutter contact point will be converted to the cutter location point and then these points fit a toolpath.Lastly,the path planning algorithm is implemented by using Matlab programming.The cutter location points for torus tool are calculated by Matlab,and then fit these points to a toolpath.While using UG software,another tool path of free surface is simulated of the same data.It is drew compared the two tool paths that using torus tool is more efficient.

Significant interarm blood pressure difference predicts cardiovascular risk in hypertensive patients

Science.gov (United States)

Kim, Su-A; Kim, Jang Young; Park, Jeong Bae

2016-01-01

Abstract There has been a rising interest in interarm blood pressure difference (IAD), due to its relationship with peripheral arterial disease and its possible relationship with cardiovascular disease. This study aimed to characterize hypertensive patients with a significant IAD in relation to cardiovascular risk. A total of 3699 patients (mean age, 61 ± 11 years) were prospectively enrolled in the study. Blood pressure (BP) was measured simultaneously in both arms 3 times using an automated cuff-oscillometric device. IAD was defined as the absolute difference in averaged BPs between the left and right arm, and an IAD ≥ 10 mm Hg was considered to be significant. The Framingham risk score was used to calculate the 10-year cardiovascular risk. The mean systolic IAD (sIAD) was 4.3 ± 4.1 mm Hg, and 285 (7.7%) patients showed significant sIAD. Patients with significant sIAD showed larger body mass index (P < 0.001), greater systolic BP (P = 0.050), more coronary artery disease (relative risk = 1.356, P = 0.034), and more cerebrovascular disease (relative risk = 1.521, P = 0.072). The mean 10-year cardiovascular risk was 9.3 ± 7.7%. By multiple regression, sIAD was significantly but weakly correlated with the 10-year cardiovascular risk (β = 0.135, P = 0.008). Patients with significant sIAD showed a higher prevalence of coronary artery disease, as well as an increase in 10-year cardiovascular risk. Therefore, accurate measurements of sIAD may serve as a simple and cost-effective tool for predicting cardiovascular risk in clinical settings. PMID:27310982

Path Creation

DEFF Research Database (Denmark)

Karnøe, Peter; Garud, Raghu

2012-01-01

This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts. Competenc......This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts....... Competencies emerged through processes and mechanisms such as co-creation that implicated multiple learning processes. The process was not an orderly linear one as emergent contingencies influenced the learning processes. An implication is that public policy to catalyse clusters cannot be based...

Global paths of time-periodic solutions of the Benjamin-Ono equation connecting arbitrary traveling waves

Energy Technology Data Exchange (ETDEWEB)

Ambrose, David M.; Wilkening, Jon

2008-12-11

We classify all bifurcations from traveling waves to non-trivial time-periodic solutions of the Benjamin-Ono equation that are predicted by linearization. We use a spectrally accurate numerical continuation method to study several paths of non-trivial solutions beyond the realm of linear theory. These paths are found to either re-connect with a different traveling wave or to blow up. In the latter case, as the bifurcation parameter approaches a critical value, the amplitude of the initial condition grows without bound and the period approaches zero. We propose a conjecture that gives the mapping from one bifurcation to its counterpart on the other side of the path of non-trivial solutions. By experimentation with data fitting, we identify the form of the exact solutions on the path connecting two traveling waves, which represents the Fourier coefficients of the solution as power sums of a finite number of particle positions whose elementary symmetric functions execute simple orbits in the complex plane (circles or epicycles). We then solve a system of algebraic equations to express the unknown constants in the new representation in terms of the mean, a spatial phase, a temporal phase, four integers (enumerating the bifurcation at each end of the path) and one additional bifurcation parameter. We also find examples of interior bifurcations from these paths of already non-trivial solutions, but we do not attempt to analyze their algebraic structure.

Potential paths for male-mediated gene flow to and from an isolated grizzly bear population

Science.gov (United States)

Peck, Christopher P.; van Manen, Frank T.; Costello, Cecily M.; Haroldson, Mark A.; Landenburger, Lisa; Roberts, Lori L.; Bjornlie, Daniel D.; Mace, Richard D.

2017-01-01

For several decades, grizzly bear populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE) have increased in numbers and range extent. The GYE population remains isolated and although effective population size has increased since the early 1980s, genetic connectivity between these populations remains a long-term management goal. With only ~110 km distance separating current estimates of occupied range for these populations, the potential for gene flow is likely greater now than it has been for many decades. We sought to delineate potential paths that would provide the opportunity for male-mediated gene flow between the two populations. We first developed step-selection functions to generate conductance layers using ecological, physical, and anthropogenic landscape features associated with non-stationary GPS locations of 124 male grizzly bears (199 bear-years). We then used a randomized shortest path (RSP) algorithm to estimate the average number of net passages for all grid cells in the study region, when moving from an origin to a destination node. Given habitat characteristics that were the basis for the conductance layer, movements follow certain grid cell sequences more than others and the resulting RSP values thus provide a measure of movement potential. Repeating this process for 100 pairs of random origin and destination nodes, we identified paths for three levels of random deviation (θ) from the least-cost path. We observed broad-scale concordance between model predictions for paths originating in the NCDE and those originating in the GYE for all three levels of movement exploration. Model predictions indicated that male grizzly bear movement between the ecosystems could involve a variety of routes, and verified observations of grizzly bears outside occupied range supported this finding. Where landscape features concentrated paths into corridors (e.g., because of anthropogenic influence), they typically

How to solve path integrals in quantum mechanics

International Nuclear Information System (INIS)

Grosche, C.

1994-10-01

A systematic classification of Feynman path integrals in quantum mechanics is presented and a table of solvable path integrals is given which reflects the progress made during the last 15 years, including, of course, the main contributions since the invention of the path integral by Feynman in 1942. An outline of the general theory is given which will serve as a quick reference for solving path integrals. Explicit formulae for the so-called basic path integrals are presented on which our general scheme to classify and calculate path integrals in quantum mechanics is based. (orig.)

Path integrals for arbitrary canonical transformations

International Nuclear Information System (INIS)

Oliveira, L.A.R. de.

1980-01-01

Some aspects of the path integral formulation of quantum mechanics are studied. This formalism is generalized to arbitrary canonical transformations, by means of an association between path integral probalility amplitudes and classical generators of transformations, analogous to the usual Hamiltonian time development phase space expression. Such association turns out to be equivalent to the Weyl quantization rule, and it is also shown that this formalism furnishes a path integral representation for a Lie algebra of a given set of classical generators. Some physical considerations about the path integral quantization procedure and about the relationship between classical and quantum dynamical structures are also discussed. (Author) [pt

Predictors of initial weight loss among women with abdominal obesity: a path model using self-efficacy and health-promoting behaviour.

Science.gov (United States)

Choo, Jina; Kang, Hyuncheol

2015-05-01

To identify predictors of initial weight loss among women with abdominal obesity by using a path model. Successful weight loss in the initial stages of long-term weight management may promote weight loss maintenance. A longitudinal study design. Study participants were 75 women with abdominal obesity, who were enrolled in a 12-month Community-based Heart and Weight Management Trial and followed until a 6-month assessment. The Weight Efficacy Lifestyle, Exercise Self-Efficacy and Health Promoting Lifestyle Profile-II measured diet self-efficacy, exercise self-efficacy and health-promoting behaviour respectively. All endogenous and exogenous variables used in our path model were change variables from baseline to 6 months. Data were collected between May 2011-May 2012. Based on the path model, increases in both diet and exercise self-efficacy had significant effects on increases in health-promoting behaviour. Increases in diet self-efficacy had a significant indirect effect on initial weight loss via increases in health-promoting behaviour. Increases in health-promoting behaviour had a significant effect on initial weight loss. Among women with abdominal obesity, increased diet self-efficacy and health-promoting behaviour were predictors of initial weight loss. A mechanism by which increased diet self-efficacy predicts initial weight loss may be partially attributable to health-promoting behavioural change. However, more work is still needed to verify causality. Based on the current findings, intensive nursing strategies for increasing self-efficacy for weight control and health-promoting behaviour may be essential components for better weight loss in the initial stage of a weight management intervention. © 2015 John Wiley & Sons Ltd.

Interference factors regarding the path of insertion of rotational-path removable partial dentures.

Science.gov (United States)

Huang, Chan-Te; Liu, Fang-Chun; Luk, Kwing-Chi

2017-02-01

The aims of this study were to evaluate the effect of the location of the rotational center and the morphology of teeth resulting in interference with the rotational path of insertion and to estimate when an interference test should be performed. A total of 400 dental radiograms of maxillary and mandibular first and second molars (100 for each position) were selected. The radiograms were used to hand-sketch the outlines on tracing paper. Then, an interference test was simulated using calipers. Mesial long occlusal rest seats with three different lengths were designed. A curve-simulated rotational path was drawn on the tracing paper showing the outline of a molar. If the curve was intersected by the mesial outline, interference was occurred. A total of 1200 tests were performed. A significant number of interference cases (18.5%, N = 400) occurred when the rotational center was placed at the most distal margin of the occlusal surface. The interference was reduced (2.75%, N = 400) but still present at the distal fourth of the occlusal surface. At the distal one-third of the occlusal surface, interference did not occur (0%, N = 400). There was a significant difference between the results of the three rotational centers (p < 0.0001). The interference test was not required for a rotational center at the distal third to half of the occlusal surface. However, if the length of the long occlusal rest extends beyond the distal third, an interference test is recommended before final impression. Copyright © 2017 Chang Gung University. Published by Elsevier B.V. All rights reserved.

Barriers to Mindfulness: a Path Analytic Model Exploring the Role of Rumination and Worry in Predicting Psychological and Physical Engagement in an Online Mindfulness-Based Intervention.

Science.gov (United States)

Banerjee, Moitree; Cavanagh, Kate; Strauss, Clara

2018-01-01

Little is known about the factors associated with engagement in mindfulness-based interventions (MBIs). Moreover, engagement in MBIs is usually defined in terms of class attendance ('physical engagement') only. However, in the psychotherapy literature, there is increasing emphasis on measuring participants' involvement with interventions ('psychological engagement'). This study tests a model that rumination and worry act as barriers to physical and psychological engagement in MBIs and that this in turn impedes learning mindfulness. One hundred and twenty-four participants were given access to a 2-week online mindfulness-based self-help (MBSH) intervention. Self-report measures of mindfulness, rumination, worry, positive beliefs about rumination, positive beliefs about worry and physical and psychological engagement were administered. A path analysis was used to test the linear relationships between the variables. Physical and psychological engagement were identified as two distinct constructs. Findings were that rumination and worry both predicted psychological disengagement in MBSH. Psychological engagement predicted change in the describe, act with awareness, non-judge and non-react facets of mindfulness while physical engagement only predicted changes in the non-react facet of mindfulness. Thus, rumination and worry may increase risk of psychological disengagement from MBSH which may in turn hinder cultivating mindfulness. Future suggestions for practice are discussed.

Sequential Path Model for Grain Yield in Soybean

Directory of Open Access Journals (Sweden)

Mohammad SEDGHI

2010-09-01

Full Text Available This study was performed to determine some physiological traits that affect soybean,s grain yield via sequential path analysis. In a factorial experiment, two cultivars (Harcor and Williams were sown under four levels of nitrogen and two levels of weed management at the research station of Tabriz University, Iran, during 2004 and 2005. Grain yield, some yield components and physiological traits were measured. Correlation coefficient analysis showed that grain yield had significant positive and negative association with measured traits. A sequential path analysis was done in order to evaluate associations among grain yield and related traits by ordering the various variables in first, second and third order paths on the basis of their maximum direct effects and minimal collinearity. Two first-order variables, namely number of pods per plant and pre-flowering net photosynthesis revealed highest direct effect on total grain yield and explained 49, 44 and 47 % of the variation in grain yield based on 2004, 2005, and combined datasets, respectively. Four traits i.e. post-flowering net photosynthesis, plant height, leaf area index and intercepted radiation at the bottom layer of canopy were found to fit as second-order variables. Pre- and post-flowering chlorophyll content, main root length and intercepted radiation at the middle layer of canopy were placed at the third-order path. From the results concluded that, number of pods per plant and pre-flowering net photosynthesis are the best selection criteria in soybean for grain yield.

Micro-CT evaluation of several glide path techniques and ProTaper Next shaping outcomes in maxillary first molar curved canals.

Science.gov (United States)

Alovisi, M; Cemenasco, A; Mancini, L; Paolino, D; Scotti, N; Bianchi, C C; Pasqualini, D

2017-04-01

To evaluate the ability of ProGlider instruments, PathFiles and K-files to maintain canal anatomy during glide path preparation using X-ray computed micro-tomography (micro-CT). Forty-five extracted maxillary first permanent molars were selected. Mesio-buccal canals were randomly assigned (n = 15) to manual K-file, PathFile or ProGlider groups for glide path preparation. Irrigation was achieved with 5% NaOCl and 10% EDTA. After glide path preparation, each canal was shaped with ProTaper Next X1 and X2 to working length. Specimens were scanned (isotropic voxel size 9.1 μm) for matching volumes and surface areas and post-treatment analyses. Canal volume, surface area, centroid shift, canal geometry variation through ratio of diameter ratios and ratio of cross-sectional areas were assessed in the apical and coronal levels and at the point of maximum canal curvature. One-way factorial anovas were used to evaluate the significance of instrument in the various canal regions. Post-glide path analysis revealed that instrument factor was significant at the apical level for both the ratio of diameter ratios and the ratio of cross-sectional areas (P flare the root canal compared with K-file and PathFile. PathFile and ProGlider demonstrated a significantly lower centroid shift compared with K-file at the apical level (P = 0.023). Post-shaping analysis demonstrated a more centred preparation of ProGlider, compared with PathFile and K-files, with no significant differences for other parameters. Use of ProGlider instruments led to less canal transportation than PathFiles and K-files. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Path probability distribution of stochastic motion of non dissipative systems: a classical analog of Feynman factor of path integral

International Nuclear Information System (INIS)

Lin, T.L.; Wang, R.; Bi, W.P.; El Kaabouchi, A.; Pujos, C.; Calvayrac, F.; Wang, Q.A.

2013-01-01

We investigate, by numerical simulation, the path probability of non dissipative mechanical systems undergoing stochastic motion. The aim is to search for the relationship between this probability and the usual mechanical action. The model of simulation is a one-dimensional particle subject to conservative force and Gaussian random displacement. The probability that a sample path between two fixed points is taken is computed from the number of particles moving along this path, an output of the simulation, divided by the total number of particles arriving at the final point. It is found that the path probability decays exponentially with increasing action of the sample paths. The decay rate increases with decreasing randomness. This result supports the existence of a classical analog of the Feynman factor in the path integral formulation of quantum mechanics for Hamiltonian systems

Control of the tritium path in process heat HTR's

International Nuclear Information System (INIS)

Kirch, N.; Scheidler, G.

1985-01-01

Nuclear Process Heat plant converting fossil fuels into liquid or gaseous secondary energy carriers generate tritium by several nuclear reactions. Control of the tritium path through the walls of the heat exchanger is highly important to meet regulatory requirements on the acceptable contamination in the product gas or liquid. Therefore, significant effort in the project 'Prototypanlage Nukleare Prozesswaerme' was put not only into generating a data base, but also into means of reducing tritium generation and permeation. Clean graphites with lithium impurities in the ppb level provide a low tritium source term. Realistic modeling of graphite retention and special helium purification systems are essentials. The main barrier to tritium permeation are heat exchanger walls requiring detailed characterization of in-situ surface layers. Studies to optimize the water/steam mass flow in the conversion process offer possibilities for further tritium retention. Progress can be demonstrated as follows: In 1980, between 2 and 8 Bq tritium per gram of product were predicted based on available data and even higher concentrations during startup. However, present day validated code predictions are below required 0.5 Bq/g equilibrium concentration level. During transients - particularly startup - this limit cannot be guaranteed as yet, but further retention potential is being offered by tritium gettering or filtering. An expected increase of the German regulatory requirement to 5 Bq/g will easily be met by present plant design under all operational conditions. (author)

Path Integral Formulation of Anomalous Diffusion Processes

OpenAIRE

Friedrich, Rudolf; Eule, Stephan

2011-01-01

We present the path integral formulation of a broad class of generalized diffusion processes. Employing the path integral we derive exact expressions for the path probability densities and joint probability distributions for the class of processes under consideration. We show that Continuous Time Random Walks (CTRWs) are included in our framework. A closed expression for the path probability distribution of CTRWs is found in terms of their waiting time distribution as the solution of a Dyson ...

Strategic Team AI Path Plans: Probabilistic Pathfinding

Directory of Open Access Journals (Sweden)

Tng C. H. John

2008-01-01

Full Text Available This paper proposes a novel method to generate strategic team AI pathfinding plans for computer games and simulations using probabilistic pathfinding. This method is inspired by genetic algorithms (Russell and Norvig, 2002, in that, a fitness function is used to test the quality of the path plans. The method generates high-quality path plans by eliminating the low-quality ones. The path plans are generated by probabilistic pathfinding, and the elimination is done by a fitness test of the path plans. This path plan generation method has the ability to generate variation or different high-quality paths, which is desired for games to increase replay values. This work is an extension of our earlier work on team AI: probabilistic pathfinding (John et al., 2006. We explore ways to combine probabilistic pathfinding and genetic algorithm to create a new method to generate strategic team AI pathfinding plans.

Clinical Significance of Hemostatic Parameters in the Prediction for Type 2 Diabetes Mellitus and Diabetic Nephropathy

Directory of Open Access Journals (Sweden)

Lianlian Pan

2018-01-01

Full Text Available It would be important to predict type 2 diabetes mellitus (T2DM and diabetic nephropathy (DN. This study was aimed at evaluating the predicting significance of hemostatic parameters for T2DM and DN. Plasma coagulation and hematologic parameters before treatment were measured in 297 T2DM patients. The risk factors and their predicting power were evaluated. T2DM patients without complications exhibited significantly different activated partial thromboplastin time (aPTT, platelet (PLT, and D-dimer (D-D levels compared with controls (P<0.01. Fibrinogen (FIB, PLT, and D-D increased in DN patients compared with those without complications (P<0.001. Both aPTT and PLT were the independent risk factors for T2DM (OR: 1.320 and 1.211, P<0.01, resp., and FIB and PLT were the independent risk factors for DN (OR: 1.611 and 1.194, P<0.01, resp.. The area under ROC curve (AUC of aPTT and PLT was 0.592 and 0.647, respectively, with low sensitivity in predicting T2DM. AUC of FIB was 0.874 with high sensitivity (85% and specificity (76% for DN, and that of PLT was 0.564, with sensitivity (60% and specificity (89% based on the cutoff values of 3.15 g/L and 245 × 109/L, respectively. This study suggests that hemostatic parameters have a low predicting value for T2DM, whereas fibrinogen is a powerful predictor for DN.

Artificial neural networks to predict presence of significant pathology in patients presenting to routine colorectal clinics.

Science.gov (United States)

Maslekar, S; Gardiner, A B; Monson, J R T; Duthie, G S

2010-12-01

Artificial neural networks (ANNs) are computer programs used to identify complex relations within data. Routine predictions of presence of colorectal pathology based on population statistics have little meaning for individual patient. This results in large number of unnecessary lower gastrointestinal endoscopies (LGEs - colonoscopies and flexible sigmoidoscopies). We aimed to develop a neural network algorithm that can accurately predict presence of significant pathology in patients attending routine outpatient clinics for gastrointestinal symptoms. Ethics approval was obtained and the study was monitored according to International Committee on Harmonisation - Good Clinical Practice (ICH-GCP) standards. Three-hundred patients undergoing LGE prospectively completed a specifically developed questionnaire, which included 40 variables based on clinical symptoms, signs, past- and family history. Complete data sets of 100 patients were used to train the ANN; the remaining data was used for internal validation. The primary output used was positive finding on LGE, including polyps, cancer, diverticular disease or colitis. For external validation, the ANN was applied to data from 50 patients in primary care and also compared with the predictions of four clinicians. Clear correlation between actual data value and ANN predictions were found (r = 0.931; P = 0.0001). The predictive accuracy of ANN was 95% in training group and 90% (95% CI 84-96) in the internal validation set and this was significantly higher than the clinical accuracy (75%). ANN also showed high accuracy in the external validation group (89%). Artificial neural networks offer the possibility of personal prediction of outcome for individual patients presenting in clinics with colorectal symptoms, making it possible to make more appropriate requests for lower gastrointestinal endoscopy. © 2010 The Authors. Colorectal Disease © 2010 The Association of Coloproctology of Great Britain and Ireland.

Link prediction in multiplex online social networks

Science.gov (United States)

Jalili, Mahdi; Orouskhani, Yasin; Asgari, Milad; Alipourfard, Nazanin; Perc, Matjaž

2017-02-01

Online social networks play a major role in modern societies, and they have shaped the way social relationships evolve. Link prediction in social networks has many potential applications such as recommending new items to users, friendship suggestion and discovering spurious connections. Many real social networks evolve the connections in multiple layers (e.g. multiple social networking platforms). In this article, we study the link prediction problem in multiplex networks. As an example, we consider a multiplex network of Twitter (as a microblogging service) and Foursquare (as a location-based social network). We consider social networks of the same users in these two platforms and develop a meta-path-based algorithm for predicting the links. The connectivity information of the two layers is used to predict the links in Foursquare network. Three classical classifiers (naive Bayes, support vector machines (SVM) and K-nearest neighbour) are used for the classification task. Although the networks are not highly correlated in the layers, our experiments show that including the cross-layer information significantly improves the prediction performance. The SVM classifier results in the best performance with an average accuracy of 89%.

Two Generations of Path Dependence

DEFF Research Database (Denmark)

Madsen, Mogens Ove

  Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences - primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

Partial Path Column Generation for the ESPPRC

DEFF Research Database (Denmark)

Jepsen, Mads Kehlet; Petersen, Bjørn

This talk introduces a decomposition of the Elementary Shortest Path Problem with Resource Constraints(ESPPRC), where the path is combined by smaller sub paths. We show computational result by comparing different approaches for the decomposition and compare the best of these with existing algorit...

Automated Prediction of Catalytic Mechanism and Rate Law Using Graph-Based Reaction Path Sampling.

Science.gov (United States)

Habershon, Scott

2016-04-12

In a recent article [ J. Chem. Phys. 2015 , 143 , 094106 ], we introduced a novel graph-based sampling scheme which can be used to generate chemical reaction paths in many-atom systems in an efficient and highly automated manner. The main goal of this work is to demonstrate how this approach, when combined with direct kinetic modeling, can be used to determine the mechanism and phenomenological rate law of a complex catalytic cycle, namely cobalt-catalyzed hydroformylation of ethene. Our graph-based sampling scheme generates 31 unique chemical products and 32 unique chemical reaction pathways; these sampled structures and reaction paths enable automated construction of a kinetic network model of the catalytic system when combined with density functional theory (DFT) calculations of free energies and resultant transition-state theory rate constants. Direct simulations of this kinetic network across a range of initial reactant concentrations enables determination of both the reaction mechanism and the associated rate law in an automated fashion, without the need for either presupposing a mechanism or making steady-state approximations in kinetic analysis. Most importantly, we find that the reaction mechanism which emerges from these simulations is exactly that originally proposed by Heck and Breslow; furthermore, the simulated rate law is also consistent with previous experimental and computational studies, exhibiting a complex dependence on carbon monoxide pressure. While the inherent errors of using DFT simulations to model chemical reactivity limit the quantitative accuracy of our calculated rates, this work confirms that our automated simulation strategy enables direct analysis of catalytic mechanisms from first principles.

Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape

Science.gov (United States)

Zhu, Q.; Lin, H. S.

2009-08-01

The importance of soil water flow paths to the transport of nutrients and contaminants has long been recognized. However, effective means of detecting concentrated subsurface flow paths in a large landscape are still lacking. The flow direction and accumulation algorithm based on single-direction flow algorithm (D8) in GIS hydrologic modeling is a cost-effective way to simulate potential concentrated flow paths over a large area once relevant data are collected. This study tested the D8 algorithm for simulating concentrated lateral flow paths at three interfaces in soil profiles in a 19.5-ha agricultural landscape in central Pennsylvania, USA. These interfaces were (1) the interface between surface plowed layers of Ap1 and Ap2 horizons, (2) the interface with subsoil water-restricting clay layer where clay content increased to over 40%, and (3) the soil-bedrock interface. The simulated flow paths were validated through soil hydrologic monitoring, geophysical surveys, and observable soil morphological features. The results confirmed that concentrated subsurface lateral flow occurred at the interfaces with the clay layer and the underlying bedrock. At these two interfaces, the soils on the simulated flow paths were closer to saturation and showed more temporally unstable moisture dynamics than those off the simulated flow paths. Apparent electrical conductivity in the soil on the simulated flow paths was elevated and temporally unstable as compared to those outside the simulated paths. The soil cores collected from the simulated flow paths showed significantly higher Mn content at these interfaces than those away from the simulated paths. These results suggest that (1) the D8 algorithm is useful in simulating possible concentrated subsurface lateral flow paths if used with appropriate threshold value of contributing area and sufficiently detailed digital elevation model (DEM); (2) repeated electromagnetic surveys can reflect the temporal change of soil water storage

The Study of Rain Specific Attenuation for the Prediction of Satellite Propagation in Malaysia

Science.gov (United States)

Mandeep, J. S.; Ng, Y. Y.; Abdullah, H.; Abdullah, M.

2010-06-01

Specific attenuation is the fundamental quantity in the calculation of rain attenuation for terrestrial path and slant paths representing as rain attenuation per unit distance (dB/km). Specific attenuation is an important element in developing the predicted rain attenuation model. This paper deals with the empirical determination of the power law coefficients which allow calculating the specific attenuation in dB/km from the knowledge of the rain rate in mm/h. The main purpose of the paper is to obtain the coefficients of k and α of power law relationship between specific attenuation. Three years (from 1st January 2006 until 31st December 2008) rain gauge and beacon data taken from USM, Nibong Tebal have been used to do the empirical procedure analysis of rain specific attenuation. The data presented are semi-empirical in nature. A year-to-year variation of the coefficients has been indicated and the empirical measured data was compared with ITU-R provided regression coefficient. The result indicated that the USM empirical measured data was significantly vary from ITU-R predicted value. Hence, ITU-R recommendation for regression coefficients of rain specific attenuation is not suitable for predicting rain attenuation at Malaysia.

Path integration on hyperbolic spaces

Energy Technology Data Exchange (ETDEWEB)

Grosche, C [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

1991-11-01

Quantum mechanics on the hyperbolic spaces of rank one is discussed by path integration technique. Hyperbolic spaces are multi-dimensional generalisation of the hyperbolic plane, i.e. the Poincare upper half-plane endowed with a hyperbolic geometry. We evalute the path integral on S{sub 1} {approx equal} SO (n,1)/SO(n) and S{sub 2} {approx equal} SU(n,1)/S(U(1) x U(n)) in a particular coordinate system, yielding explicitly the wave-functions and the energy spectrum. Futhermore we can exploit a general property of all these spaces, namely that they can be parametrized by a pseudopolar coordinate system. This allows a separation in path integration over spheres and an additional path integration over the remaining hyperbolic coordinate, yielding effectively a path integral for a modified Poeschl-Teller potential. Only continuous spectra can exist in all the cases. For all the hyperbolic spaces of rank one we find a general formula for the largest lower bound (zero-point energy) of the spectrum which is given by E{sub O} = h{sup 2} /8m(m{sub {alpha}} +2m{sub 2} {alpha}){sup 2} (m {alpha} and m{sub 2}{alpha} denote the dimension of the root subspace corresponding to the roots {alpha} and 2{alpha}, respectively). I also discuss the case, where a constant magnetic field on H{sup n} is incorporated. (orig.).

Path integration on hyperbolic spaces

International Nuclear Information System (INIS)

Grosche, C.

1991-11-01

Quantum mechanics on the hyperbolic spaces of rank one is discussed by path integration technique. Hyperbolic spaces are multi-dimensional generalisation of the hyperbolic plane, i.e. the Poincare upper half-plane endowed with a hyperbolic geometry. We evalute the path integral on S 1 ≅ SO (n,1)/SO(n) and S 2 ≅ SU(n,1)/S[U(1) x U(n)] in a particular coordinate system, yielding explicitly the wave-functions and the energy spectrum. Futhermore we can exploit a general property of all these spaces, namely that they can be parametrized by a pseudopolar coordinate system. This allows a separation in path integration over spheres and an additional path integration over the remaining hyperbolic coordinate, yielding effectively a path integral for a modified Poeschl-Teller potential. Only continuous spectra can exist in all the cases. For all the hyperbolic spaces of rank one we find a general formula for the largest lower bound (zero-point energy) of the spectrum which is given by E O = h 2 /8m(m α +2m 2 α) 2 (m α and m 2 α denote the dimension of the root subspace corresponding to the roots α and 2α, respectively). I also discuss the case, where a constant magnetic field on H n is incorporated. (orig.)

Predicting significant torso trauma.

Science.gov (United States)

Nirula, Ram; Talmor, Daniel; Brasel, Karen

2005-07-01

Identification of motor vehicle crash (MVC) characteristics associated with thoracoabdominal injury would advance the development of automatic crash notification systems (ACNS) by improving triage and response times. Our objective was to determine the relationships between MVC characteristics and thoracoabdominal trauma to develop a torso injury probability model. Drivers involved in crashes from 1993 to 2001 within the National Automotive Sampling System were reviewed. Relationships between torso injury and MVC characteristics were assessed using multivariate logistic regression. Receiver operating characteristic curves were used to compare the model to current ACNS models. There were a total of 56,466 drivers. Age, ejection, braking, avoidance, velocity, restraints, passenger-side impact, rollover, and vehicle weight and type were associated with injury (p < 0.05). The area under the receiver operating characteristic curve (83.9) was significantly greater than current ACNS models. We have developed a thoracoabdominal injury probability model that may improve patient triage when used with ACNS.

PSO-Based Robot Path Planning for Multisurvivor Rescue in Limited Survival Time

Directory of Open Access Journals (Sweden)

N. Geng

2014-01-01

Full Text Available Since the strength of a trapped person often declines with time in urgent and dangerous circumstances, adopting a robot to rescue as many survivors as possible in limited time is of considerable significance. However, as one key issue in robot navigation, how to plan an optimal rescue path of a robot has not yet been fully solved. This paper studies robot path planning for multisurvivor rescue in limited survival time using a representative heuristic, particle swarm optimization (PSO. First, the robot path planning problem including multiple survivors is formulated as a discrete optimization one with high constraint, where the number of rescued persons is taken as the unique objective function, and the strength of a trapped person is used to constrain the feasibility of a path. Then, a new integer PSO algorithm is presented to solve the mathematical model, and several new operations, such as the update of a particle, the insertion and inversion operators, and the rapidly local search method, are incorporated into the proposed algorithm to improve its effectiveness. Finally, the simulation results demonstrate the capacity of our method in generating optimal paths with high quality.

Using the Integrative Model of Behavioral Prediction to Understand College Students' STI Testing Beliefs, Intentions, and Behaviors.

Science.gov (United States)

Wombacher, Kevin; Dai, Minhao; Matig, Jacob J; Harrington, Nancy Grant

2018-03-22

To identify salient behavioral determinants related to STI testing among college students by testing a model based on the integrative model of behavioral (IMBP) prediction. 265 undergraduate students from a large university in the Southeastern US. Formative and survey research to test an IMBP-based model that explores the relationships between determinants and STI testing intention and behavior. Results of path analyses supported a model in which attitudinal beliefs predicted intention and intention predicted behavior. Normative beliefs and behavioral control beliefs were not significant in the model; however, select individual normative and control beliefs were significantly correlated with intention and behavior. Attitudinal beliefs are the strongest predictor of STI testing intention and behavior. Future efforts to increase STI testing rates should identify and target salient attitudinal beliefs.

SFR inverse modelling Part 2. Uncertainty factors of predicted flow in deposition tunnels and uncertainty in distribution of flow paths from deposition tunnels

International Nuclear Information System (INIS)

Holmen, Johan

2007-10-01

The Swedish Nuclear Fuel and Waste Management Co (SKB) is operating the SFR repository for low- and intermediate-level nuclear waste. An update of the safety analysis of SFR was carried out by SKB as the SAFE project (Safety Assessment of Final Disposal of Operational Radioactive Waste). The aim of the project was to update the safety analysis and to produce a safety report. The safety report has been submitted to the Swedish authorities. This study is a continuation of the SAFE project, and concerns the hydrogeological modelling of the SFR repository, which was carried out as part of the SAFE project, it describes the uncertainty in the tunnel flow and distributions of flow paths from the storage tunnels. Uncertainty factors are produced for two different flow situations, corresponding to 2,000 AD (the sea covers the repository) and 4,000 AD (the sea has retreated form the repository area). Uncertainty factors are produced for the different deposition tunnels. The uncertainty factors are discussed in Chapter 2 and two lists (matrix) of uncertainty factors have been delivered as a part of this study. Flow paths are produced for two different flow situations, corresponding to 2,000 AD (the sea covers the repository) and 5,000 AD (the sea has retreated form the repository area). Flow paths from the different deposition tunnels have been simulated, considering the above discussed base case and the 60 realisation that passed all tests of this base case. The flow paths are presented and discussed in Chapter 3 and files presenting the results of the flow path analyses have been delivered as part of this study. The uncertainty factors (see Chapter 2) are not independent from the flow path data (see Chapter 3). When stochastic calculations are performed by use of a transport model and the data presented in this study is used as input to such calculations, the corresponding uncertainty factors and flow path data should be used. This study also includes a brief discussion of

The Japanese energy sector: Current situation, and future paths

International Nuclear Information System (INIS)

Takase, Kae; Suzuki, Tatsujiro

2011-01-01

As the world's third leading economy and a major importer of fuels, the choice of future energy paths and policies that Japan makes in the next few years will have a significant influence on the energy security of the world as a whole, and of the Northeast Asia region in particular. In this article we describe the current status of and recent trends in the Japanese energy sector, including energy demand and supply by fuel and by sector. We then discuss the current energy policy situation in Japan, focusing on policies related to climate change targets, renewable energy development and deployment, liberalization of energy markets, and the evolution of the Japanese nuclear power sector. The final section of the article presents the structure of the Japan LEAP (long-range energy alternatives planning software system) dataset, describes several alternative energy paths for Japan - with an emphasis on alternative paths for nuclear power development and GHG emission abatement - and touches upon key current issues of energy policy facing Japan, as reflected in the modeling inputs and results.

The Japanese energy sector: Current situation, and future paths

Energy Technology Data Exchange (ETDEWEB)

Takase, Kae, E-mail: kae@gdl.jp [Governance Design Laboratory, Inc., 2301 City Tower Bashamichi 5-71 Onoe-cho, Naka-ku, Yokohama, Kanagawa 231-0015 (Japan); Suzuki, Tatsujiro [University of Tokyo, Graduate School of Public Policy, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0081 (Japan)

2011-11-15

As the world's third leading economy and a major importer of fuels, the choice of future energy paths and policies that Japan makes in the next few years will have a significant influence on the energy security of the world as a whole, and of the Northeast Asia region in particular. In this article we describe the current status of and recent trends in the Japanese energy sector, including energy demand and supply by fuel and by sector. We then discuss the current energy policy situation in Japan, focusing on policies related to climate change targets, renewable energy development and deployment, liberalization of energy markets, and the evolution of the Japanese nuclear power sector. The final section of the article presents the structure of the Japan LEAP (long-range energy alternatives planning software system) dataset, describes several alternative energy paths for Japan - with an emphasis on alternative paths for nuclear power development and GHG emission abatement - and touches upon key current issues of energy policy facing Japan, as reflected in the modeling inputs and results.

The Use of a Reciprocating Handpiece to Create a Glide Path in Curved Canals: Comparison with Manual Glide Path Preparation

Science.gov (United States)

2016-06-01

instruments into the root canal system, manufacturers recommend creating a glide path to reduce the risk of instrument fracture due to taper lock . This...Results The two groups had almost identical mean and standard...The groups had identical median values of 85 seconds, and there was no significant difference between the groups (Mann-Whitney U test; p=0.15; two

Statistical significance of theoretical predictions: A new dimension in nuclear structure theories (I)

International Nuclear Information System (INIS)

DUDEK, J; SZPAK, B; FORNAL, B; PORQUET, M-G

2011-01-01

In this and the follow-up article we briefly discuss what we believe represents one of the most serious problems in contemporary nuclear structure: the question of statistical significance of parametrizations of nuclear microscopic Hamiltonians and the implied predictive power of the underlying theories. In the present Part I, we introduce the main lines of reasoning of the so-called Inverse Problem Theory, an important sub-field in the contemporary Applied Mathematics, here illustrated on the example of the Nuclear Mean-Field Approach.

Shortest path problem on a grid network with unordered intermediate points

Science.gov (United States)

Saw, Veekeong; Rahman, Amirah; Eng Ong, Wen

2017-10-01

We consider a shortest path problem with single cost factor on a grid network with unordered intermediate points. A two stage heuristic algorithm is proposed to find a feasible solution path within a reasonable amount of time. To evaluate the performance of the proposed algorithm, computational experiments are performed on grid maps of varying size and number of intermediate points. Preliminary results for the problem are reported. Numerical comparisons against brute forcing show that the proposed algorithm consistently yields solutions that are within 10% of the optimal solution and uses significantly less computation time.

Vacuum stress and closed paths in rectangles, pistons and pistols

International Nuclear Information System (INIS)

Fulling, S A; Kaplan, L; Kirsten, K; Liu, Z H; Milton, K A

2009-01-01

Rectangular cavities are solvable models that nevertheless touch on many of the controversial or mysterious aspects of the vacuum energy of quantum fields. This paper is a thorough study of the two-dimensional scalar field in a rectangle by the method of images, or closed classical (or optical) paths, which is exact in this case. For each point r and each specularly reflecting path beginning and ending at r, we provide formulae for all components of the stress tensor T μν (r), for all values of the curvature coupling constant ξ and all values of an ultraviolet cutoff parameter. Arbitrary combinations of Dirichlet and Neumann conditions on the four sides can be treated. The total energy is also investigated, path by path. These results are used in an attempt to clarify the physical reality of the repulsive (outward) force on the sides of the box predicted by calculations that neglect both boundary divergences and the exterior of the box. Previous authors have studied 'piston' geometries that avoid these problems and have found the force to be attractive. We consider a 'pistol' geometry that comes closer to the original problem of a box with a movable lid. We find again an attractive force, although its origin and detailed behavior are somewhat different from the piston case. However, the pistol (and the piston) model can be criticized for extending idealized boundary conditions into short distances where they are physically implausible. Therefore, it is of interest to see whether leaving the ultraviolet cutoff finite yields results that are more plausible. We then find that the force depends strongly on a geometrical parameter; it can be made repulsive, but only by forcing that parameter into the regime where the model is least convincing physically

Path Integration on the Upper Half-Plane

OpenAIRE

Reijiro, KUBO; Research Institute for Theoretical Physics Hiroshima University

1987-01-01

Feynman's path integral is considered on the Poincare upper half-plane. It is shown that the fundamental solution to the heat equation ∂f/∂t=Δ_Hf can be expressed in terms of a path integral. A simple relation between the path integral and the Selberg trace formula is discussed briefly.

Pedestrian paths: why path-dependence theory leaves health policy analysis lost in space.

Science.gov (United States)

Brown, Lawrence D

2010-08-01

Path dependence, a model first advanced to explain puzzles in the diffusion of technology, has lately won allegiance among analysts of the politics of public policy, including health care policy. Though the central premise of the model--that past events and decisions shape options for innovation in the present and future--is indisputable (indeed path dependence is, so to speak, too shallow to be false), the approach, at least as applied to health policy, suffers from ambiguities that undercut its claims to illuminate policy projects such as managed care, on which this article focuses. Because path dependence adds little more than marginal value to familiar images of the politics of policy--incrementalism, for one--analysts might do well to put it on the back burner and pursue instead "thick descriptions" that help them to distinguish different degrees of openness to exogenous change among diverse policy arenas.

The Thinnest Path Problem

Science.gov (United States)

2016-07-22

be reduced to TP in -D UDH for any . We then show that the 2-D disk hypergraph constructed in the proof of Theorem 1 can be modified to an exposed...transmission range that induces hy- peredge , i.e., (3) GAO et al.: THINNEST PATH PROBLEM 1181 Theorem 5 shows that the covered area of the path...representation of (the two hyperedges rooted at from the example given in Fig. 6 are illustrated in green and blue, respectively). step, we show in this

Implementation of PATHS through Dutch Municipal Health Services: A Quasi-Experiment

Directory of Open Access Journals (Sweden)

Ferry X. Goossens

2012-12-01

Full Text Available Only a limited number of effectiveness studies have been performed to study the benefits of efficacious behavior problems prevention programs for children when implemented through national health service systems. This study uses a quasi-experimental design to test the effectiveness of the school-based PATHS prevention program (Providing Alternative THinking Strategies when implemented through Dutch municipal health services by health promotion professionals. A sample of 1,294 children was followed for two years: 674 children attending nine schools providing PATHS and 620 children in nine comparison schools. We hypothesized finding an intervention effect of PATHS in terms of a significant reduction in teacher- and student-rated externalizing and internalizing problem behaviors, and a significant improvement in teacher-, student-, and peer-rated social skills and emotional skills. In fact, the results show low levels of programimplementation and no intervention effects on problem behavior or social and emotional skills, suggesting that it is hard to reproduce positive intervention effects where an efficacious social-emotional prevention program is implemented through a national health service. More research is needed on the specific conditions required to implement efficacious programs effectively.

Investigation of Prediction Accuracy, Sensitivity, and Parameter Stability of Large-Scale Propagation Path Loss Models for 5G Wireless Communications

DEFF Research Database (Denmark)

Sun, Shu; Rappaport, Theodore S.; Thomas, Timothy

2016-01-01

This paper compares three candidate large-scale propagation path loss models for use over the entire microwave and millimeter-wave (mmWave) radio spectrum: the alpha–beta–gamma (ABG) model, the close-in (CI) free-space reference distance model, and the CI model with a frequency-weighted path loss...... exponent (CIF). Each of these models has been recently studied for use in standards bodies such as 3rd Generation Partnership Project (3GPP) and for use in the design of fifth generation wireless systems in urban macrocell, urban microcell, and indoor office and shopping mall scenarios. Here, we compare...

Curvature-Continuous 3D Path-Planning Using QPMI Method

Directory of Open Access Journals (Sweden)

Seong-Ryong Chang

2015-06-01

Full Text Available It is impossible to achieve vertex movement and rapid velocity control in aerial robots and aerial vehicles because of momentum from the air. A continuous-curvature path ensures such robots and vehicles can fly with stable and continuous movements. General continuous path-planning methods use spline interpolation, for example B-spline and Bézier curves. However, these methods cannot be directly applied to continuous path planning in a 3D space. These methods use a subset of the waypoints to decide curvature and some waypoints are not included in the planned path. This paper proposes a method for constructing a curvature-continuous path in 3D space that includes every waypoint. The movements in each axis, x, y and z, are separated by the parameter u. Waypoint groups are formed, each with its own continuous path derived using quadratic polynomial interpolation. The membership function then combines each continuous path into one continuous path. The continuity of the path is verified and the curvature-continuous path is produced using the proposed method.

Path integration on the upper half-plane

International Nuclear Information System (INIS)

Kubo, Reijiro.

1987-06-01

Feynman's path integral is considered on the Poincare upper half-plane. It is shown that the fundamental solution to the heat equation δf/δt = Δ H f can be expressed in terms of a path integral. A simple relation between the path integral and the Selberg trace formula is discussed briefly. (author)

Glide path preparation in S-shaped canals with rotary pathfinding nickel-titanium instruments.

Science.gov (United States)

Ajuz, Natasha C C; Armada, Luciana; Gonçalves, Lucio S; Debelian, Gilberto; Siqueira, José F

2013-04-01

This study compared the incidence of deviation along S-shaped (double-curved) canals after glide path preparation with 2 nickel-titanium (NiTi) rotary pathfinding instruments and hand K-files. S-shaped canals from 60 training blocks were filled with ink, and preinstrumentation images were obtained by using a stereomicroscope. Glide path preparation was performed by an endodontist who used hand stainless steel K-files (up to size 20), rotary NiTi PathFile instruments (up to size 19), or rotary NiTi Scout RaCe instruments (up to size 20). Postinstrumentation images were taken by using exactly the same conditions as for the preinstrumentation images, and both pictures were superimposed. Differences along the S-shaped canal for the mesial and distal aspects were measured to evaluate the occurrence of deviation. Intragroup analysis showed that all instruments promoted some deviation in virtually all levels. Overall, regardless of the group, deviations were observed in the mesial wall at the canal terminus and at levels 4, 5, 6 and 7 mm and in the distal wall at levels 1, 2, and 3 mm. These levels corresponded to the inner walls of each curvature. Both rotary NiTi instruments performed significantly better than hand K-files at all levels (P instruments showed significantly better results than PathFiles at levels 0, 2, 3, 5, and 6 mm (P rotary NiTi instruments are suitable for adequate glide path preparation because they promoted less deviation from the original canal anatomy when compared with hand-operated instruments. Of the 2 rotary pathfinding instruments, Scout RaCe showed an overall significantly better performance. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Combining control input with flight path data to evaluate pilot performance in transport aircraft.

Science.gov (United States)

Ebbatson, Matt; Harris, Don; Huddlestone, John; Sears, Rodney

2008-11-01

When deriving an objective assessment of piloting performance from flight data records, it is common to employ metrics which purely evaluate errors in flight path parameters. The adequacy of pilot performance is evaluated from the flight path of the aircraft. However, in large jet transport aircraft these measures may be insensitive and require supplementing with frequency-based measures of control input parameters. Flight path and control input data were collected from pilots undertaking a jet transport aircraft conversion course during a series of symmetric and asymmetric approaches in a flight simulator. The flight path data were analyzed for deviations around the optimum flight path while flying an instrument landing approach. Manipulation of the flight controls was subject to analysis using a series of power spectral density measures. The flight path metrics showed no significant differences in performance between the symmetric and asymmetric approaches. However, control input frequency domain measures revealed that the pilots employed highly different control strategies in the pitch and yaw axes. The results demonstrate that to evaluate pilot performance fully in large aircraft, it is necessary to employ performance metrics targeted at both the outer control loop (flight path) and the inner control loop (flight control) parameters in parallel, evaluating both the product and process of a pilot's performance.

Chromatic roots and hamiltonian paths

DEFF Research Database (Denmark)

Thomassen, Carsten

2000-01-01

We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result...

Path diversity improves the identification of influential spreaders

Science.gov (United States)

Chen, Duan-Bing; Xiao, Rui; Zeng, An; Zhang, Yi-Cheng

2013-12-01

Identifying influential spreaders in complex networks is a crucial problem which relates to wide applications. Many methods based on the global information such as K-shell and PageRank have been applied to rank spreaders. However, most of the related previous works overwhelmingly focus on the number of paths for propagation, while whether the paths are diverse enough is usually overlooked. Generally, the spreading ability of a node might not be strong if its propagation depends on one or two paths while the other paths are dead ends. In this letter, we introduced the concept of path diversity and find that it can largely improve the ranking accuracy. We further propose a local method combining the information of path number and path diversity to identify influential nodes in complex networks. This method is shown to outperform many well-known methods in both undirected and directed networks. Moreover, the efficiency of our method makes it possible to apply it to very large systems.

Codification of scan path parameters and development of perimeter scan strategies for 3D bowl-shaped laser forming

Science.gov (United States)

Tavakoli, A.; Naeini, H. Moslemi; Roohi, Amir H.; Gollo, M. Hoseinpour; Shahabad, Sh. Imani

2018-01-01

In the 3D laser forming process, developing an appropriate laser scan pattern for producing specimens with high quality and uniformity is critical. This study presents certain principles for developing scan paths. Seven scan path parameters are considered, including: (1) combined linear or curved path; (2) type of combined linear path; (3) order of scan sequences; (4) the position of the start point in each scan; (5) continuous or discontinuous scan path; (6) direction of scan path; and (7) angular arrangement of combined linear scan paths. Regarding these path parameters, ten combined linear scan patterns are presented. Numerical simulations show continuous hexagonal, scan pattern, scanning from outer to inner path, is the optimized. In addition, it is observed the position of the start point and the angular arrangement of scan paths is the most effective path parameters. Also, further experimentations show four sequences due to creat symmetric condition enhance the height of the bowl-shaped products and uniformity. Finally, the optimized hexagonal pattern was compared with the similar circular one. In the hexagonal scan path, distortion value and standard deviation rather to edge height of formed specimen is very low, and the edge height despite of decreasing length of scan path increases significantly compared to the circular scan path. As a result, four-sequence hexagonal scan pattern is proposed as the optimized perimeter scan path to produce bowl-shaped product.

Electron Inelastic-Mean-Free-Path Database

Science.gov (United States)

SRD 71 NIST Electron Inelastic-Mean-Free-Path Database (PC database, no charge)   This database provides values of electron inelastic mean free paths (IMFPs) for use in quantitative surface analyses by AES and XPS.

Hanford spent nuclear fuel project recommended path forward, volume III: Alternatives and path forward evaluation supporting documentation

International Nuclear Information System (INIS)

Fulton, J.C.

1994-10-01

Volume I of the Hanford Spent Nuclear Fuel Project - Recommended Path Forward constitutes an aggressive series of projects to construct and operate systems and facilities to safely retrieve, package, transport, process, and store K Basins fuel and sludge. Volume II provided a comparative evaluation of four Alternatives for the Path Forward and an evaluation for the Recommended Path Forward. Although Volume II contained extensive appendices, six supporting documents have been compiled in Volume III to provide additional background for Volume II

Using GPS RO L1 data for calibration of the atmospheric path delay model for data reduction of the satellite altimetery observations.

Science.gov (United States)

Petrov, L.

2017-12-01

Processing satellite altimetry data requires the computation of path delayin the neutral atmosphere that is used for correcting ranges. The path delayis computed using numerical weather models and the accuracy of its computationdepends on the accuracy of numerical weather models. Accuracy of numerical modelsof numerical weather models over Antarctica and Greenland where there is a very sparse network of ground stations, is not well known. I used the dataset of GPS RO L1 data, computed predicted path delay for ROobservations using the numerical whether model GEOS-FPIT, formed the differences with observed path delay and used these differences for computationof the corrections to the a priori refractivity profile. These profiles wereused for computing corrections to the a priori zenith path delay. The systematic patter of these corrections are used for de-biasing of the the satellite altimetry results and for characterization of the systematic errorscaused by mismodeling atmosphere.

Understanding and applying open-path optical sensing data

Science.gov (United States)

Virag, Peter; Kricks, Robert J.

1999-02-01

During the last 10 years, open-path air monitors have evolved to yield reliable and effective measurements of single and multiple compounds on a real-time basis. To many individuals within the optical remote sensing community, the attributes of open-path and its the potential uses seem unlimited. Then why has the market has been stagnant for the last few years? The reason may center on how open-path information is applied and how well the end user understands that information. We constantly try to compare open-path data to risk/health or safety levels that are based for use at a single point and for a specific averaging period often far longer than a typical open-path data point. Often this approach is perceived as putting a square peg in a round hole. This perception may be well founded, as open-path data at times may need to go through extensive data manipulation and assumptions before it can be applied. This paper will review pervious open-path monitoring programs and their success in applying the data collected. We will also look at how open-path data is being currently used, some previous pitfalls in data use, alternate methods of data interpretation, and how open-path data can be best practically applied to fit current needs.

Unusual bond paths in organolithium compounds

International Nuclear Information System (INIS)

Bachrach, S.M.; Ritchie, J.P.

1986-01-01

We have applied the topological method to a number of organolithium compounds. The wavefunctions were determined with GAUSSIAN-82 using 3-21G basis set and fully optimized geometries. Gradient paths were obtained using the RHODER package and critical points were located using EXTREME. These results indicate the unusual nature of organolithium compounds. The strange bond paths arise mainly from the ionic nature of the C-Li interaction. We suggest that the term ''bond path'' may best be suited for covalent bonds. 4 figs., 1 tab

Predicting Sympathy and Prosocial Behavior from Young Children’s Dispositional Sadness

Science.gov (United States)

Edwards, Alison; Eisenberg, Nancy; Spinrad, Tracy L.; Reiser, Mark; Eggum-Wilkens, Natalie D.; Liew, Jeffrey

2014-01-01

The purpose of this study was to examine whether dispositional sadness predicted children's prosocial behavior and if sympathy mediated this relation. Constructs were measured when children (N = 256 at Time 1) were 18-, 30-, and 42-months old. Mothers and non-parental caregivers rated children’s sadness; mothers, caregivers, and fathers rated children’s prosocial behavior; sympathy (concern and hypothesis testing) and prosocial behavior (indirect and direct, as well as verbal at older ages) were assessed with a task in which the experimenter feigned injury. In a panel path analysis, 30-month dispositional sadness predicted marginally higher 42-month sympathy; in addition, 30-month sympathy predicted 42-month sadness. Moreover, when controlling for prior levels of prosocial behavior, 30-month sympathy significantly predicted reported and observed prosocial behavior at 42 months. Sympathy did not mediate the relation between sadness and prosocial behavior (either reported or observed). PMID:25663753

Postoperative pain after manual and mechanical glide path: a randomized clinical trial.

Science.gov (United States)

Pasqualini, Damiano; Mollo, Livio; Scotti, Nicola; Cantatore, Giuseppe; Castellucci, Arnaldo; Migliaretti, Giuseppe; Berutti, Elio

2012-01-01

This prospective randomized clinical trial evaluated the incidence of postoperative pain after glide path performed with PathFile (PF) (Dentsply Maillefer, Ballaigues, Switzerland) versus stainless-steel K-file (KF). In 149 subjects, the mechanical glide path was performed with nickel-titanium (NiTi) rotary PF; in 146 subjects, the manual glide path was performed with stainless-steel KFs. Postoperative pain, analgesics consumption, and the number of days to complete pain resolution were evaluated in the following 7 days. An analysis of variance model for repeated measures was used to compare the variation of pain-scale values (P < .05). The Student's t test for continuous variables normally distributed, the nonparametric Mann-Whitney U test for the nonnormally distributed variables, and the chi-square test for dichotomous variables were used (P < .05). Despite homogeneous baseline conditions at diagnosis, tooth type, pain prevalence, and scores, the postoperative pain prevalence curves in PF group evidenced a more favorable trend in terms of time to pain resolution compared with the KF group (P = .004). The difference was also evident in the model adjusted for analgesics consumption in both groups (P = .012). The mean analgesics intake per subject was significantly higher in the KF group (3.7 ± 2.2) compared with the PF group (2 ± 1.7) (P < .001). Mean pain stop values were also significantly higher in the KF group (2.7) compared with the PF group (1.7) (P = .001). The glide path with NiTi Rotary PF leads to less postoperative pain and faster symptom resolution. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Tuning of Lee Path Loss Model based on recent RF measurements in 400 MHZ conducted in Riyadh City, Saudi Arabia

International Nuclear Information System (INIS)

Alotaibi, Faihan D.; Ali, Adel A.

2008-01-01

In mobile radio systems, path loss models are necessary for proper planning, interference estimations, frequently assignments and cell parameters which are basic for network planning process as well as Location Based Services (LBS) techniques that are not based on GPS system. Empirical models are the most adjustable models that can be suited to different types of environments. In this paper, the Lee path loss model has been tuned using Least Square (LS) algorithm to fit measured data for TETRA system operating 400 MHz in Riyadh urban and suburbs. Consequently, Lee model's parameter (L0, y) are obtained for the targeted areas. The performance of the tuned Lee model is then compared to the three most widely used empirical path loss models: Hat, ITU-R and Cost 231 Walfisch-Ikegami non line-of-sight (CWI-NLOS) path loss models. The performance criterion selected for the comparison of various empirical path loss models are the Root Mean Square Error (RMSE) and goodness of fit (R2). The RMSE and R2between the actual and predicted data are calculated for various path loss models. It turned that the tuned Lee model outperforms the other empirical models. (author)

Two-path plasmonic interferometer with integrated detector

Science.gov (United States)

Dyer, Gregory Conrad; Shaner, Eric A.; Aizin, Gregory

2016-03-29

An electrically tunable terahertz two-path plasmonic interferometer with an integrated detection element can down convert a terahertz field to a rectified DC signal. The integrated detector utilizes a resonant plasmonic homodyne mixing mechanism that measures the component of the plasma waves in-phase with an excitation field that functions as the local oscillator in the mixer. The plasmonic interferometer comprises two independently tuned electrical paths. The plasmonic interferometer enables a spectrometer-on-a-chip where the tuning of electrical path length plays an analogous role to that of physical path length in macroscopic Fourier transform interferometers.

Actively learning human gaze shifting paths for semantics-aware photo cropping.

Science.gov (United States)

Zhang, Luming; Gao, Yue; Ji, Rongrong; Xia, Yingjie; Dai, Qionghai; Li, Xuelong

2014-05-01

Photo cropping is a widely used tool in printing industry, photography, and cinematography. Conventional cropping models suffer from the following three challenges. First, the deemphasized role of semantic contents that are many times more important than low-level features in photo aesthetics. Second, the absence of a sequential ordering in the existing models. In contrast, humans look at semantically important regions sequentially when viewing a photo. Third, the difficulty of leveraging inputs from multiple users. Experience from multiple users is particularly critical in cropping as photo assessment is quite a subjective task. To address these challenges, this paper proposes semantics-aware photo cropping, which crops a photo by simulating the process of humans sequentially perceiving semantically important regions of a photo. We first project the local features (graphlets in this paper) onto the semantic space, which is constructed based on the category information of the training photos. An efficient learning algorithm is then derived to sequentially select semantically representative graphlets of a photo, and the selecting process can be interpreted by a path, which simulates humans actively perceiving semantics in a photo. Furthermore, we learn a prior distribution of such active graphlet paths from training photos that are marked as aesthetically pleasing by multiple users. The learned priors enforce the corresponding active graphlet path of a test photo to be maximally similar to those from the training photos. Experimental results show that: 1) the active graphlet path accurately predicts human gaze shifting, and thus is more indicative for photo aesthetics than conventional saliency maps and 2) the cropped photos produced by our approach outperform its competitors in both qualitative and quantitative comparisons.

A prediction score for significant coronary artery disease in Chinese patients ≥50 years old referred for rheumatic valvular heart disease surgery.

Science.gov (United States)

Xu, Zhenjun; Pan, Jun; Chen, Tao; Zhou, Qing; Wang, Qiang; Cao, Hailong; Fan, Fudong; Luo, Xuan; Ge, Min; Wang, Dongjin

2018-04-01

Our goal was to establish a prediction score and protocol for the preoperative prediction of significant coronary artery disease (CAD) in patients with rheumatic valvular heart disease. Using multivariate logistic regression analysis, we validated the model based on 490 patients without a history of myocardial infarction and who underwent preoperative screening coronary angiography. Significant CAD was defined as ≥50% narrowing of the diameter of the lumen of the left main coronary artery or ≥70% narrowing of the diameter of the lumen of the left anterior descending coronary artery, left circumflex artery or right coronary artery. Significant CAD was present in 9.8% of patients. Age, smoking, diabetes mellitus, diastolic blood pressure, low-density lipoprotein cholesterol and ischaemia evident on an electrocardiogram were independently associated with significant CAD and were entered into the multivariate model. According to the logistic regression predictive risk score, preoperative coronary angiography is recommended in (i) postmenopausal women between 50 and 59 years of age with ≥9.1% logistic regression predictive risk score; (ii) postmenopausal women who are ≥60 years old with a logistic regression predictive risk score ≥6.6% and (iii) men ≥50 years old whose logistic regression predictive risk score was ≥2.8%. Based on this predictive model, 246 (50.2%) preoperative coronary angiograms could be safely avoided. The negative predictive value of the model was 98.8% (246 of 249). This model was accurate for the preoperative prediction of significant CAD in patients with rheumatic valvular heart disease. This model must be validated in larger cohorts and various populations.

Prediction of Path Deviation in Robot Based Incremental Sheet Metal Forming by Means of a New Solid-Shell Finite Element Technology and a Finite Elastoplastic Model with Combined Hardening

Science.gov (United States)

Kiliclar, Yalin; Laurischkat, Roman; Vladimirov, Ivaylo N.; Reese, Stefanie

2011-08-01

The presented project deals with a robot based incremental sheet metal forming process, which is called roboforming and has been developed at the Chair of Production Systems. It is characterized by flexible shaping using a freely programmable path-synchronous movement of two industrial robots. The final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the part contour in lateral direction. However, the resulting geometries formed in roboforming deviate several millimeters from the reference geometry. This results from the compliance of the involved machine structures and the springback effects of the workpiece. The project aims to predict these deviations caused by resiliences and to carry out a compensative path planning based on this prediction. Therefore a planning tool is implemented which compensates the robots's compliance and the springback effects of the sheet metal. The forming process is simulated by means of a finite element analysis using a material model developed at the Institute of Applied Mechanics (IFAM). It is based on the multiplicative split of the deformation gradient in the context of hyperelasticity and combines nonlinear kinematic and isotropic hardening. Low-order finite elements used to simulate thin sheet structures, such as used for the experiments, have the major problem of locking, a nonphysical stiffening effect. For an efficient finite element analysis a special solid-shell finite element formulation based on reduced integration with hourglass stabilization has been developed. To circumvent different locking effects, the enhanced assumed strain (EAS) and the assumed natural strain (ANS) concepts are included in this formulation. Having such powerful tools available we obtain more accurate geometries.

Optimization of educational paths for higher education

Science.gov (United States)

Tarasyev, Alexandr A.; Agarkov, Gavriil; Medvedev, Aleksandr

2017-11-01

In our research, we combine the theory of economic behavior and the methodology of increasing efficiency of the human capital to estimate the optimal educational paths. We provide an optimization model for higher education process to analyze possible educational paths for each rational individual. The preferences of each rational individual are compared to the best economically possible educational path. The main factor of the individual choice, which is formed by the formation of optimal educational path, deals with higher salaries level in the chosen economic sector after graduation. Another factor that influences on the economic profit is the reduction of educational costs or the possibility of the budget support for the student. The main outcome of this research consists in correction of the governmental policy of investment in human capital based on the results of educational paths optimal control.

Data-Based Predictive Control with Multirate Prediction Step

Science.gov (United States)

Barlow, Jonathan S.

2010-01-01

Data-based predictive control is an emerging control method that stems from Model Predictive Control (MPC). MPC computes current control action based on a prediction of the system output a number of time steps into the future and is generally derived from a known model of the system. Data-based predictive control has the advantage of deriving predictive models and controller gains from input-output data. Thus, a controller can be designed from the outputs of complex simulation code or a physical system where no explicit model exists. If the output data happens to be corrupted by periodic disturbances, the designed controller will also have the built-in ability to reject these disturbances without the need to know them. When data-based predictive control is implemented online, it becomes a version of adaptive control. One challenge of MPC is computational requirements increasing with prediction horizon length. This paper develops a closed-loop dynamic output feedback controller that minimizes a multi-step-ahead receding-horizon cost function with multirate prediction step. One result is a reduced influence of prediction horizon and the number of system outputs on the computational requirements of the controller. Another result is an emphasis on portions of the prediction window that are sampled more frequently. A third result is the ability to include more outputs in the feedback path than in the cost function.

Path operator algebras in conformal quantum field theories

International Nuclear Information System (INIS)

Roesgen, M.

2000-10-01

Two different kinds of path algebras and methods from noncommutative geometry are applied to conformal field theory: Fusion rings and modular invariants of extended chiral algebras are analyzed in terms of essential paths which are a path description of intertwiners. As an example, the ADE classification of modular invariants for minimal models is reproduced. The analysis of two-step extensions is included. Path algebras based on a path space interpretation of character identities can be applied to the analysis of fusion rings as well. In particular, factorization properties of character identities and therefore of the corresponding path spaces are - by means of K-theory - related to the factorization of the fusion ring of Virasoro- and W-algebras. Examples from nonsupersymmetric as well as N=2 supersymmetric minimal models are discussed. (orig.)

Crack path in liquid metal embrittlement: experiments with steels and modeling

Directory of Open Access Journals (Sweden)

T. Auger

2016-01-01

Full Text Available We review the recent experimental clarification of the fracture path in Liquid Metal Embrittlement with austenitic and martensitic steels. Using state of the art characterization tools (Focused Ion Beam and Transmission Electron Microscopy a clear understanding of crack path is emerging for these systems where a classical fractographic analysis fails to provide useful information. The main finding is that most of the cracking process takes place at grain boundaries, lath or mechanical twin boundaries while cleavage or plastic flow localization is rarely the observed fracture mode. Based on these experimental insights, we sketch an on-going modeling strategy for LME crack initiation and propagation at mesoscopic scale. At the microstructural scale, crystal plasticity constitutive equations are used to model the plastic deformation in metals and alloys. The microstructure used is either extracted from experimental measurements by 3D-EBSD (Electron Back Scattering Diffraction or simulated starting from a Voronoï approach. The presence of a crackwithin the polycrystalline aggregate is taken into account in order to study the surrounding plastic dissipation and the crack path. One key piece of information that can be extracted is the typical order of magnitude of the stress-strain state at GB in order to constrain crack initiation models. The challenges of building predictive LME cracking models are outlined.

A path flux analysis method for the reduction of detailed chemical kinetic mechanisms

Energy Technology Data Exchange (ETDEWEB)

Sun, Wenting; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871 (China); Gou, Xiaolong [School of Power Engineering, Chongqing University, Chongqing 400044 (China)

2010-07-15

A direct path flux analysis (PFA) method for kinetic mechanism reduction is proposed and validated by using high temperature ignition, perfect stirred reactors, and steady and unsteady flame propagations of n-heptane and n-decane/air mixtures. The formation and consumption fluxes of each species at multiple reaction path generations are analyzed and used to identify the important reaction pathways and the associated species. The formation and consumption path fluxes used in this method retain flux conservation information and are used to define the path indexes for the first and the second generation reaction paths related to a targeted species. Based on the indexes of each reaction path for the first and second generations, different sized reduced chemical mechanisms which contain different number of species are generated. The reduced mechanisms of n-heptane and n-decane obtained by using the present method are compared to those generated by the direct relation graph (DRG) method. The reaction path analysis for n-decane is conducted to demonstrate the validity of the present method. The comparisons of the ignition delay times, flame propagation speeds, flame structures, and unsteady spherical flame propagation processes showed that with either the same or significantly less number of species, the reduced mechanisms generated by the present PFA are more accurate than that of DRG in a broad range of initial pressures and temperatures. The method is also integrated with the dynamic multi-timescale method and a further increase of computation efficiency is achieved. (author)

Physiologically-based, predictive analytics using the heart-rate-to-Systolic-Ratio significantly improves the timeliness and accuracy of sepsis prediction compared to SIRS.

Science.gov (United States)

Danner, Omar K; Hendren, Sandra; Santiago, Ethel; Nye, Brittany; Abraham, Prasad

2017-04-01

Enhancing the efficiency of diagnosis and treatment of severe sepsis by using physiologically-based, predictive analytical strategies has not been fully explored. We hypothesize assessment of heart-rate-to-systolic-ratio significantly increases the timeliness and accuracy of sepsis prediction after emergency department (ED) presentation. We evaluated the records of 53,313 ED patients from a large, urban teaching hospital between January and June 2015. The HR-to-systolic ratio was compared to SIRS criteria for sepsis prediction. There were 884 patients with discharge diagnoses of sepsis, severe sepsis, and/or septic shock. Variations in three presenting variables, heart rate, systolic BP and temperature were determined to be primary early predictors of sepsis with a 74% (654/884) accuracy compared to 34% (304/884) using SIRS criteria (p < 0.0001)in confirmed septic patients. Physiologically-based predictive analytics improved the accuracy and expediency of sepsis identification via detection of variations in HR-to-systolic ratio. This approach may lead to earlier sepsis workup and life-saving interventions. Copyright © 2017 Elsevier Inc. All rights reserved.

Computing the optimal path in stochastic dynamical systems

International Nuclear Information System (INIS)

Bauver, Martha; Forgoston, Eric; Billings, Lora

2016-01-01

In stochastic systems, one is often interested in finding the optimal path that maximizes the probability of escape from a metastable state or of switching between metastable states. Even for simple systems, it may be impossible to find an analytic form of the optimal path, and in high-dimensional systems, this is almost always the case. In this article, we formulate a constructive methodology that is used to compute the optimal path numerically. The method utilizes finite-time Lyapunov exponents, statistical selection criteria, and a Newton-based iterative minimizing scheme. The method is applied to four examples. The first example is a two-dimensional system that describes a single population with internal noise. This model has an analytical solution for the optimal path. The numerical solution found using our computational method agrees well with the analytical result. The second example is a more complicated four-dimensional system where our numerical method must be used to find the optimal path. The third example, although a seemingly simple two-dimensional system, demonstrates the success of our method in finding the optimal path where other numerical methods are known to fail. In the fourth example, the optimal path lies in six-dimensional space and demonstrates the power of our method in computing paths in higher-dimensional spaces.

Path lumping: An efficient algorithm to identify metastable path channels for conformational dynamics of multi-body systems

Science.gov (United States)

Meng, Luming; Sheong, Fu Kit; Zeng, Xiangze; Zhu, Lizhe; Huang, Xuhui

2017-07-01

Constructing Markov state models from large-scale molecular dynamics simulation trajectories is a promising approach to dissect the kinetic mechanisms of complex chemical and biological processes. Combined with transition path theory, Markov state models can be applied to identify all pathways connecting any conformational states of interest. However, the identified pathways can be too complex to comprehend, especially for multi-body processes where numerous parallel pathways with comparable flux probability often coexist. Here, we have developed a path lumping method to group these parallel pathways into metastable path channels for analysis. We define the similarity between two pathways as the intercrossing flux between them and then apply the spectral clustering algorithm to lump these pathways into groups. We demonstrate the power of our method by applying it to two systems: a 2D-potential consisting of four metastable energy channels and the hydrophobic collapse process of two hydrophobic molecules. In both cases, our algorithm successfully reveals the metastable path channels. We expect this path lumping algorithm to be a promising tool for revealing unprecedented insights into the kinetic mechanisms of complex multi-body processes.

Moments of inertia and the shapes of Brownian paths

International Nuclear Information System (INIS)

Fougere, F.; Desbois, J.

1993-01-01

The joint probability law of the principal moments of inertia of Brownian paths (open or closed) is computed, using constrained path integrals and Random Matrix Theory. The case of two-dimensional paths is discussed in detail. In particular, it is shown that the ratio of the average values of the largest and smallest moments is equal to 4.99 (open paths) and 3.07 (closed paths). Results of numerical simulations are also presented, which include investigation of the relationships between the moments of inertia and the arithmetic area enclosed by a path. (authors) 28 refs., 2 figs

Association of manual or engine-driven glide path preparation with canal centring and apical transportation: a systematic review.

Science.gov (United States)

Hartmann, R C; Peters, O A; de Figueiredo, J A P; Rossi-Fedele, G

2018-04-28

The role and effect of glide path preparation in root canal treatment remain controversial. This systematic review aims to compare apical transportation and canal centring of different glide path preparation techniques, with or without subsequent engine-driven root canal preparation. A database search in PubMed, PubMed Central, Embase, Scopus, EBSCO Dentistry & Oral Sciences Source and Virtual Health Library was conducted, using appropriate key words to identify the effect of glide path preparation (or its absence) on apical transportation and canal centring. An assessment for the risk of bias in included studies was carried out. Amongst 2146 studies, 18 satisfied the inclusion criteria. Nine studies assessed glide path preparation per se, comparing apical transportation and canal centring of rotary systems and/or manual files; eleven further investigations examined the efficacy of the glide path prior to final canal preparation with different engine-driven systems. Risk of bias and other study design features with potential influence on study outcomes and clinical implications were assessed. Based on the available evidence, and within the limitation of the studies included, preparation of a glide path using rotary sequences performs similarly (in most of the component studies) or significantly better than manual preparation when assessing apical transportation or canal centring. When compared to the absence of a glide path, canal shaping following glide path preparation was of similar, or significantly better quality, in regard to apical transportation or canal centring. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A Local Search Modeling for Constrained Optimum Paths Problems (Extended Abstract

Directory of Open Access Journals (Sweden)

Quang Dung Pham

2009-10-01

Full Text Available Constrained Optimum Path (COP problems appear in many real-life applications, especially on communication networks. Some of these problems have been considered and solved by specific techniques which are usually difficult to extend. In this paper, we introduce a novel local search modeling for solving some COPs by local search. The modeling features the compositionality, modularity, reuse and strengthens the benefits of Constrained-Based Local Search. We also apply the modeling to the edge-disjoint paths problem (EDP. We show that side constraints can easily be added in the model. Computational results show the significance of the approach.

Directional maximum likelihood self-estimation of the path-loss exponent

NARCIS (Netherlands)

Hu, Y.; Leus, G.J.T.; Dong, Min; Zheng, Thomas Fang

2016-01-01

The path-loss exponent (PLE) is a key parameter in wireless propagation channels. Therefore, obtaining the knowledge of the PLE is rather significant for assisting wireless communications and networking to achieve a better performance. Most existing methods for estimating the PLE not only require

A split-path schema-based RFID data storage model in supply chain management.

Science.gov (United States)

Fan, Hua; Wu, Quanyuan; Lin, Yisong; Zhang, Jianfeng

2013-05-03

In modern supply chain management systems, Radio Frequency IDentification (RFID) technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing approaches cannot satisfy the requirements of RFID data management. In this paper, we present a split-path schema-based RFID data storage model. With a data separation mechanism, the massive RFID data produced in supply chain management systems can be stored and processed more efficiently. Then a tree structure-based path splitting approach is proposed to intelligently and automatically split the movement paths of products . Furthermore, based on the proposed new storage model, we design the relational schema to store the path information and time information of tags, and some typical query templates and SQL statements are defined. Finally, we conduct various experiments to measure the effect and performance of our model and demonstrate that it performs significantly better than the baseline approach in both the data expression and path-oriented RFID data query performance.

A Split-Path Schema-Based RFID Data Storage Model in Supply Chain Management

Directory of Open Access Journals (Sweden)

Jianfeng Zhang

2013-05-01

Full Text Available In modern supply chain management systems, Radio Frequency IDentification (RFID technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing approaches cannot satisfy the requirements of RFID data management. In this paper, we present a split-path schema-based RFID data storage model. With a data separation mechanism, the massive RFID data produced in supply chain management systems can be stored and processed more efficiently. Then a tree structure-based path splitting approach is proposed to intelligently and automatically split the movement paths of products . Furthermore, based on the proposed new storage model, we design the relational schema to store the path information and time information of tags, and some typical query templates and SQL statements are defined. Finally, we conduct various experiments to measure the effect and performance of our model and demonstrate that it performs significantly better than the baseline approach in both the data expression and path-oriented RFID data query performance.

In-line femtosecond common-path interferometer in reflection mode.

Science.gov (United States)

Chandezon, J; Rampnoux, J-M; Dilhaire, S; Audoin, B; Guillet, Y

2015-10-19

An innovative method to perform femtosecond time-resolved interferometry in reflection mode is proposed. The experiment consists in the combined use of a pump-probe setup and of a fully passive in-line femtosecond common-path interferometer. The originality of this interferometer relies on the use of a single birefringent crystal first to generate a pair of phase-locked pulses and second to recombine them to interfere. As predicted by analytical modeling, this interferometer measures the temporal derivative of the ultrafast changes of the complex optical reflection coefficient of the sample. Working conditions are illustrated through picosecond opto-acoustic experiments on a thin film.

76 FR 17064 - Shared Use Path Accessibility Guidelines

Science.gov (United States)

2011-03-28

...] RIN 3014-AA41 Shared Use Path Accessibility Guidelines AGENCY: Architectural and Transportation... (ANPRM) to develop accessibility guidelines for shared use paths. Shared use paths are designed for both... users. The guidelines will include technical provisions for making newly constructed and altered shared...

A focussed dynamic path finding algorithm with constraints

CSIR Research Space (South Africa)

Leenen, L

2013-11-01

Full Text Available heuristic to focus the search for an optimal path. Existing approaches to solving path planning problems tend to combine path costs with various other criteria such as obstacle avoidance in the objective function which is being optimised. The authors...

Path probability of stochastic motion: A functional approach

Science.gov (United States)

Hattori, Masayuki; Abe, Sumiyoshi

2016-06-01

The path probability of a particle undergoing stochastic motion is studied by the use of functional technique, and the general formula is derived for the path probability distribution functional. The probability of finding paths inside a tube/band, the center of which is stipulated by a given path, is analytically evaluated in a way analogous to continuous measurements in quantum mechanics. Then, the formalism developed here is applied to the stochastic dynamics of stock price in finance.

Energy vs. density on paths toward more exact density functionals.

Science.gov (United States)

Kepp, Kasper P

2018-03-14

Recently, the progression toward more exact density functional theory has been questioned, implying a need for more formal ways to systematically measure progress, i.e. a "path". Here I use the Hohenberg-Kohn theorems and the definition of normality by Burke et al. to define a path toward exactness and "straying" from the "path" by separating errors in ρ and E[ρ]. A consistent path toward exactness involves minimizing both errors. Second, a suitably diverse test set of trial densities ρ' can be used to estimate the significance of errors in ρ without knowing the exact densities which are often inaccessible. To illustrate this, the systems previously studied by Medvedev et al., the first ionization energies of atoms with Z = 1 to 10, the ionization energy of water, and the bond dissociation energies of five diatomic molecules were investigated using CCSD(T)/aug-cc-pV5Z as benchmark at chemical accuracy. Four functionals of distinct designs was used: B3LYP, PBE, M06, and S-VWN. For atomic cations regardless of charge and compactness up to Z = 10, the energy effects of the different ρ are energy-wise insignificant. An interesting oscillating behavior in the density sensitivity is observed vs. Z, explained by orbital occupation effects. Finally, it is shown that even large "normal" problems such as the Co-C bond energy of cobalamins can use simpler (e.g. PBE) trial densities to drastically speed up computation by loss of a few kJ mol -1 in accuracy. The proposed method of using a test set of trial densities to estimate the sensitivity and significance of density errors of functionals may be useful for testing and designing new balanced functionals with more systematic improvement of densities and energies.

Land-mobile satellite excess path loss measurements

Science.gov (United States)

Hess, G. C.

1980-05-01

An experiment conducted with the ATS-6 satellite to determine the additional path loss over free-space loss experienced by land-mobile communication links is described. This excess path loss is measured as a function of 1) local environment, 2) vehicle heading, 3) link frequency, 4) satellite elevation angle, and 5) street side. A statistical description of excess loss developed from the data shows that the first two parameters dominate. Excess path loss on the order of 25 dB is typical in urban situations, but decreases to under 10 dB in suburban/rural areas. Spaced antenna selection diversity is found to provide only a slight decrease (4 dB, typically) in the urban excess path loss observed. Level crossing rates are depressed in satellite links relative to those of Rayleigh-faded terrestrial links, but increases in average fade durations tend to offset that advantage. The measurements show that the excess path loss difference between 860-MHz links and 1550-MHz links is generally negligible.

Perfect discretization of reparametrization invariant path integrals

International Nuclear Information System (INIS)

Bahr, Benjamin; Dittrich, Bianca; Steinhaus, Sebastian

2011-01-01

To obtain a well-defined path integral one often employs discretizations. In the case of gravity and reparametrization-invariant systems, the latter of which we consider here as a toy example, discretizations generically break diffeomorphism and reparametrization symmetry, respectively. This has severe implications, as these symmetries determine the dynamics of the corresponding system. Indeed we will show that a discretized path integral with reparametrization-invariance is necessarily also discretization independent and therefore uniquely determined by the corresponding continuum quantum mechanical propagator. We use this insight to develop an iterative method for constructing such a discretized path integral, akin to a Wilsonian RG flow. This allows us to address the problem of discretization ambiguities and of an anomaly-free path integral measure for such systems. The latter is needed to obtain a path integral, that can act as a projector onto the physical states, satisfying the quantum constraints. We will comment on implications for discrete quantum gravity models, such as spin foams.

Perfect discretization of reparametrization invariant path integrals

Science.gov (United States)

Bahr, Benjamin; Dittrich, Bianca; Steinhaus, Sebastian

2011-05-01

To obtain a well-defined path integral one often employs discretizations. In the case of gravity and reparametrization-invariant systems, the latter of which we consider here as a toy example, discretizations generically break diffeomorphism and reparametrization symmetry, respectively. This has severe implications, as these symmetries determine the dynamics of the corresponding system. Indeed we will show that a discretized path integral with reparametrization-invariance is necessarily also discretization independent and therefore uniquely determined by the corresponding continuum quantum mechanical propagator. We use this insight to develop an iterative method for constructing such a discretized path integral, akin to a Wilsonian RG flow. This allows us to address the problem of discretization ambiguities and of an anomaly-free path integral measure for such systems. The latter is needed to obtain a path integral, that can act as a projector onto the physical states, satisfying the quantum constraints. We will comment on implications for discrete quantum gravity models, such as spin foams.

Path integral for relativistic particle theory

International Nuclear Information System (INIS)

Fradkin, E.S.; Gitman, D.M.; Shvartsman, Sh.M.

1990-06-01

An action for a relativistic spinning particle interacting with external electromagnetic field is considered in reparametrization and local supergauge invariant form. It is shown that various path integral representations derived for the causal Green function correspond to the different forms of the relativistic particle action. The analogy of the path integral derived with the Lagrangian path integral of the field theory is discussed. It is shown that to obtain the causal propagator, the integration over the null mode of the Lagrangian multiplier corresponding to the reparametrization invariance, has to be performed in the (0,+infinity) limits. (author). 23 refs

Positroids Induced by Rational Dyck Paths

OpenAIRE

Gotti, Felix

2017-01-01

A rational Dyck path of type $(m,d)$ is an increasing unit-step lattice path from $(0,0)$ to $(m,d) \\in \\mathbb{Z}^2$ that never goes above the diagonal line $y = (d/m)x$. On the other hand, a positroid of rank $d$ on the ground set $[d+m]$ is a special type of matroid coming from the totally nonnegative Grassmannian. In this paper we describe how to naturally assign a rank $d$ positroid on the ground set $[d+m]$, which we name rational Dyck positroid, to each rational Dyck path of type $(m,d...

Realizing spaces as path-component spaces

OpenAIRE

Banakh, Taras; Brazas, Jeremy

2018-01-01

The path component space of a topological space $X$ is the quotient space $\\pi_0(X)$ whose points are the path components of $X$. We show that every Tychonoff space $X$ is the path-component space of a Tychonoff space $Y$ of weight $w(Y)=w(X)$ such that the natural quotient map $Y\\to \\pi_0(Y)=X$ is a perfect map. Hence, many topological properties of $X$ transfer to $Y$. We apply this result to construct a compact space $X\\subset \\mathbb{R}^3$ for which the fundamental group $\\pi_1(X,x_0)$ is...

Quantum circuit dynamics via path integrals: Is there a classical action for discrete-time paths?

Science.gov (United States)

Penney, Mark D.; Enshan Koh, Dax; Spekkens, Robert W.

2017-07-01

It is straightforward to compute the transition amplitudes of a quantum circuit using the sum-over-paths methodology when the gates in the circuit are balanced, where a balanced gate is one for which all non-zero transition amplitudes are of equal magnitude. Here we consider the question of whether, for such circuits, the relative phases of different discrete-time paths through the configuration space can be defined in terms of a classical action, as they are for continuous-time paths. We show how to do so for certain kinds of quantum circuits, namely, Clifford circuits where the elementary systems are continuous-variable systems or discrete systems of odd-prime dimension. These types of circuit are distinguished by having phase-space representations that serve to define their classical counterparts. For discrete systems, the phase-space coordinates are also discrete variables. We show that for each gate in the generating set, one can associate a symplectomorphism on the phase-space and to each of these one can associate a generating function, defined on two copies of the configuration space. For discrete systems, the latter association is achieved using tools from algebraic geometry. Finally, we show that if the action functional for a discrete-time path through a sequence of gates is defined using the sum of the corresponding generating functions, then it yields the correct relative phases for the path-sum expression. These results are likely to be relevant for quantizing physical theories where time is fundamentally discrete, characterizing the classical limit of discrete-time quantum dynamics, and proving complexity results for quantum circuits.

Purely geometric path integral for spin-foams

International Nuclear Information System (INIS)

Shirazi, Atousa Chaharsough; Engle, Jonathan

2014-01-01

Spin-foams are a proposal for defining the dynamics of loop quantum gravity via path integral. In order for a path integral to be at least formally equivalent to the corresponding canonical quantization, at each point in the space of histories it is important that the integrand have not only the correct phase—a topic of recent focus in spin-foams—but also the correct modulus, usually referred to as the measure factor. The correct measure factor descends from the Liouville measure on the reduced phase space, and its calculation is a task of canonical analysis. The covariant formulation of gravity from which spin-foams are derived is the Plebanski–Holst formulation, in which the basic variables are a Lorentz connection and a Lorentz-algebra valued 2-form, called the Plebanski 2-form. However, in the final spin-foam sum, one usually sums over only spins and intertwiners, which label eigenstates of the Plebanski 2-form alone. The spin-foam sum is therefore a discretized version of a Plebanski–Holst path integral in which only the Plebanski 2-form appears, and in which the connection degrees of freedom have been integrated out. We call this a purely geometric Plebanski–Holst path integral. In prior work in which one of the authors was involved, the measure factor for the Plebanski–Holst path integral with both connection and 2-form variables was calculated. Before one discretizes this measure and incorporates it into a spin-foam sum, however, one must integrate out the connection in order to obtain the purely geometric version of the path integral. To calculate this purely geometric path integral is the principal task of the present paper, and it is done in two independent ways. Background independence of the resulting path integral is discussed in the final section, and gauge-fixing is discussed in appendix B. (paper)

Acquisition Path Analysis as a Collaborative Activity

International Nuclear Information System (INIS)

Nakao, A.; Grundule, R.; Gushchyn, K.; El Gebaly, A.; Higgy, R.; Tsvetkov, I.; Mandl, W.

2015-01-01

In the International Atomic Energy Agency, acquisition path analysis (APA) is indispensable to safeguards implementation. It is an integral part of both State evaluation process and the development of State level safeguards approaches, all performed through ongoing collaborative analysis of all available safeguards relevant information by State evaluation groups (SEG) with participation of other contributors, as required. To perform comprehensive State evaluation, to develop and revise State-level safeguards approaches, and to prepare annual implementation plans, the SEG in its collaborative analysis follows accepted safeguards methodology and guidance. In particular, the guide ''Performing Acquisition Path Analysis for the Development of a State-level Safeguards Approach for a State with a CSA'' is used. This guide identifies four major steps of the APA process: 1. Consolidating information about the State's past, present and planned nuclear fuel cycle-related capabilities and infrastructure; 2. Identifying and visually presenting technically plausible acquisition paths for the State; 3. Assessing acquisition path steps (State's technical capabilities and possible actions) along the identified acquisition paths; and 4. Assessing the time needed to accomplish each identified technically plausible acquisition path for the State. The paper reports on SEG members' and other contributors' experience with APA when following the above steps, including the identification of plausible acquisition pathways, estimation of time frames for all identified steps and determination of the time needed to accomplish each acquisition path. The difficulties that the SEG encountered during the process of performing the APA are also addressed. Feedback in the form of practical suggestions for improving the clarity of the acquisition path step assessment forms and a proposal for software support are also included. (author)

Modeling heading and path perception from optic flow in the case of independently moving objects

Science.gov (United States)

Raudies, Florian; Neumann, Heiko

2013-01-01

Humans are usually accurate when estimating heading or path from optic flow, even in the presence of independently moving objects (IMOs) in an otherwise rigid scene. To invoke significant biases in perceived heading, IMOs have to be large and obscure the focus of expansion (FOE) in the image plane, which is the point of approach. For the estimation of path during curvilinear self-motion no significant biases were found in the presence of IMOs. What makes humans robust in their estimation of heading or path using optic flow? We derive analytical models of optic flow for linear and curvilinear self-motion using geometric scene models. Heading biases of a linear least squares method, which builds upon these analytical models, are large, larger than those reported for humans. This motivated us to study segmentation cues that are available from optic flow. We derive models of accretion/deletion, expansion/contraction, acceleration/deceleration, local spatial curvature, and local temporal curvature, to be used as cues to segment an IMO from the background. Integrating these segmentation cues into our method of estimating heading or path now explains human psychophysical data and extends, as well as unifies, previous investigations. Our analysis suggests that various cues available from optic flow help to segment IMOs and, thus, make humans' heading and path perception robust in the presence of such IMOs. PMID:23554589

Modeling Heading and Path Perception from Optic Flow in the Case of Independently Moving Objects

Directory of Open Access Journals (Sweden)

Florian eRaudies

2013-04-01

Full Text Available Humans are usually accurate when estimating heading or path from optic flow, even in the presence of independently moving objects (IMO in an otherwise rigid scene. To invoke significant biases in perceived heading, IMOs have to be large and obscure the focus of expansion (FOE in the image plane, which is the point of approach. For the estimation of path during curvilinear self-motion no significant biases were found in the presence of IMOs. What makes humans robust in their estimation of heading or path using optic flow? We derive analytical models of optic flow for linear and curvilinear self-motion using geometric scene models. Heading biases of a linear least squares method, which builds upon these analytical models, are large, larger than those reported for humans. This motivated us to study segmentation cues that are available from optic flow. We derive models of accretion / deletion, expansion / contraction, acceleration / deceleration, local spatial curvature, and local temporal curvature, to be used as cues to segment an IMO from the background. Integrating these segmentation cues into our method of estimating heading or path now explains human psychophysical data and extends, as well as unifies, previous investigations. Our analysis suggests that various cues available from optic flow help to segment IMOs and, thus, make humans’ heading and path perception robust in the presence of such IMOs.

Predicting Comorbid Conditions and Trajectories using Social Health Records.

Science.gov (United States)

Ji, Xiang; Ae Chun, Soon; Geller, James

2016-05-05

Many patients suffer from comorbidity conditions, for example, obese patients often develop type-2 diabetes and hypertension. In the US, 80% of Medicare spending is for managing patients with these multiple coexisting conditions. Predicting potential comorbidity conditions for an individual patient can promote preventive care and reduce costs. Predicting possible comorbidity progression paths can provide important insights into population heath and aid with decisions in public health policies. Discovering the comorbidity relationships is complex and difficult, due to limited access to Electronic Health Records by privacy laws. In this paper, we present a collaborative comorbidity prediction method to predict likely comorbid conditions for individual patients, and a trajectory prediction graph model to reveal progression paths of comorbid conditions. Our prediction approaches utilize patient generated health reports on online social media, called Social Health Records (SHR). The experimental results based on one SHR source show that our method is able to predict future comorbid conditions for a patient with coverage values of 48% and 75% for a top-20 and a top-100 ranked list, respectively. For risk trajectory prediction, our approach is able to reveal each potential progression trajectory between any two conditions and infer the confidence of the future trajectory, given any observed condition. The predicted trajectories are validated with existing comorbidity relations from the medical literature.

Path dependence and creation

DEFF Research Database (Denmark)

Garud, Raghu; Karnøe, Peter

This edited volume stems from a conference held in Copenhagen that the authors ran in August of 1997. The authors, aware of the recent work in evolutionary theory and the science of chaos and complexity, challenge the sometimes deterministic flavour of this work. They are interested in uncovering...... the place of agency in these theories that take history so seriously. In the end, they are as interested in path creation and destruction as they are in path dependence. This book is compiled of both theoretical and empirical writing. It shows relatively well-known industries such as the automobile...

A Study of Relationship between Leader Behaviors and Subordinate Job Expectancies: A Path-Goal Approach

Directory of Open Access Journals (Sweden)

Sikandar Hayyat Malik

2012-12-01

Full Text Available This study investigates relationship between leader behavior (directive, supportive, participative and achievement-oriented of corporate managers and subordinates’ job expectancies using House (1974 Path-goal model of leadership. The results reveal thatleader behavior affects subordinates’ job expectancies. The situational factors (task structure, role ambiguity, stress, need for autonomy, locus of control, need for achievement and perception about abilities affect subordinates’ job expectancies (I&II.While subordinates’ attributes/characteristics (age, gender, qualification, rank, experience and length of service under the current supervisor do not affect job expectancies (I&II except for rank/position and expectancy-II. Path goal theory predicts that directive leader behavior will be more effective for the subordinates with high need for achievement because directive leader through clarifying path guides subordinates. Similarly, participative leader behavior is also effective as heconsults with subordinates in setting, clarifying and achieving goals. The results of this study reveal that there is an inverse relationship between subordinates’ job expectancy (I&II. According to Yukl (2006, for subordinates with high need for autonomy,participative leader behavior will increase the intrinsic valence of work.

Perfect discretization of path integrals

OpenAIRE

Steinhaus, Sebastian

2011-01-01

In order to obtain a well-defined path integral one often employs discretizations. In the case of General Relativity these generically break diffeomorphism symmetry, which has severe consequences since these symmetries determine the dynamics of the corresponding system. In this article we consider the path integral of reparametrization invariant systems as a toy example and present an improvement procedure for the discretized propagator. Fixed points and convergence of the procedure are discu...

28 CFR 36.403 - Alterations: Path of travel.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Alterations: Path of travel. 36.403... Alterations: Path of travel. (a) General. An alteration that affects or could affect the usability of or... the maximum extent feasible, the path of travel to the altered area and the restrooms, telephones, and...

Paths and cycles in colored graphs

NARCIS (Netherlands)

Li, Xueliang; Zhang, Shenggui; Hurink, Johann L.; Pickl, Stefan; Broersma, Haitze J.; Faigle, U.

2001-01-01

Let G be an (edge-)colored graph. A path (cycle) is called monochromatic if all the edges of it have the same color, and is called heterochromatic if all the edges of it have different colors. In this note, some sufficient conditions for the existence of monochromatic and heterochromatic paths and

Quantum circuit dynamics via path integrals: Is there a classical action for discrete-time paths?

International Nuclear Information System (INIS)

Penney, Mark D; Koh, Dax Enshan; Spekkens, Robert W

2017-01-01

It is straightforward to compute the transition amplitudes of a quantum circuit using the sum-over-paths methodology when the gates in the circuit are balanced, where a balanced gate is one for which all non-zero transition amplitudes are of equal magnitude. Here we consider the question of whether, for such circuits, the relative phases of different discrete-time paths through the configuration space can be defined in terms of a classical action, as they are for continuous-time paths. We show how to do so for certain kinds of quantum circuits, namely, Clifford circuits where the elementary systems are continuous-variable systems or discrete systems of odd-prime dimension. These types of circuit are distinguished by having phase-space representations that serve to define their classical counterparts. For discrete systems, the phase-space coordinates are also discrete variables. We show that for each gate in the generating set, one can associate a symplectomorphism on the phase-space and to each of these one can associate a generating function, defined on two copies of the configuration space. For discrete systems, the latter association is achieved using tools from algebraic geometry. Finally, we show that if the action functional for a discrete-time path through a sequence of gates is defined using the sum of the corresponding generating functions, then it yields the correct relative phases for the path-sum expression. These results are likely to be relevant for quantizing physical theories where time is fundamentally discrete, characterizing the classical limit of discrete-time quantum dynamics, and proving complexity results for quantum circuits. (paper)

The formal path integral and quantum mechanics

International Nuclear Information System (INIS)

Johnson-Freyd, Theo

2010-01-01

Given an arbitrary Lagrangian function on R d and a choice of classical path, one can try to define Feynman's path integral supported near the classical path as a formal power series parameterized by 'Feynman diagrams', although these diagrams may diverge. We compute this expansion and show that it is (formally, if there are ultraviolet divergences) invariant under volume-preserving changes of coordinates. We prove that if the ultraviolet divergences cancel at each order, then our formal path integral satisfies a 'Fubini theorem' expressing the standard composition law for the time evolution operator in quantum mechanics. Moreover, we show that when the Lagrangian is inhomogeneous quadratic in velocity such that its homogeneous-quadratic part is given by a matrix with constant determinant, then the divergences cancel at each order. Thus, by 'cutting and pasting' and choosing volume-compatible local coordinates, our construction defines a Feynman-diagrammatic 'formal path integral' for the nonrelativistic quantum mechanics of a charged particle moving in a Riemannian manifold with an external electromagnetic field.

A New Method of Global Path Planning for AGV

Institute of Scientific and Technical Information of China (English)

SHI En-xiu; HUANG Yu-mei

2006-01-01

Path planning is important in the research of a mobile robot (MR). Methods for it have been used in different applications. An automated guided vehicle(AGV), which is a kind of MR, is used in a flexible manufacturing system(FMS). Path planning for it is essential to improve the efficiency of FMS. A new method was proposed with known obstacle space FMS in this paper. FMS is described by the Augmented Pos Matrix of a Machine (APMM) and Relative Pos Matrix of Machines (RPMM), which is smaller. The optimum path can be obtained according to the probability of the path and the maximal probability path. The suggested algorithm of path planning was good performance through simulation result: simplicity, saving time and reliability.

FindPath: a Matlab solution for in silico design of synthetic metabolic pathways.

Science.gov (United States)

Vieira, Gilles; Carnicer, Marc; Portais, Jean-Charles; Heux, Stéphanie

2014-10-15

Several methods and computational tools have been developed to design novel metabolic pathways. A major challenge is evaluating the metabolic efficiency of the designed pathways in the host organism. Here we present FindPath, a unified system to predict and rank possible pathways according to their metabolic efficiency in the cellular system. This tool uses a chemical reaction database to generate possible metabolic pathways and exploits constraint-based models (CBMs) to identify the most efficient synthetic pathway to achieve the desired metabolic function in a given host microorganism. FindPath can be used with common tools for CBM manipulation and uses the standard SBML format for both input and output files. http://metasys.insa-toulouse.fr/software/findpath/. heux@insa-toulouse.fr Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Phase-space path-integral calculation of the Wigner function

International Nuclear Information System (INIS)

Samson, J H

2003-01-01

The Wigner function W(q, p) is formulated as a phase-space path integral, whereby its sign oscillations can be seen to follow from interference between the geometrical phases of the paths. The approach has similarities to the path-centroid method in the configuration-space path integral. Paths can be classified by the midpoint of their ends; short paths where the midpoint is close to (q, p) and which lie in regions of low energy (low P function of the Hamiltonian) will dominate, and the enclosed area will determine the sign of the Wigner function. As a demonstration, the method is applied to a sequence of density matrices interpolating between a Poissonian number distribution and a number state, each member of which can be represented exactly by a discretized path integral with a finite number of vertices. Saddle-point evaluation of these integrals recovers (up to a constant factor) the WKB approximation to the Wigner function of a number state

Optimized path planning for soft tissue resection via laser vaporization

Science.gov (United States)

Ross, Weston; Cornwell, Neil; Tucker, Matthew; Mann, Brian; Codd, Patrick

2018-02-01

Robotic and robotic-assisted surgeries are becoming more prevalent with the promise of improving surgical outcomes through increased precision, reduced operating times, and minimally invasive procedures. The handheld laser scalpel in neurosurgery has been shown to provide a more gentle approach to tissue manipulation on or near critical structures over classical tooling, though difficulties of control have prevented large scale adoption of the tool. This paper presents a novel approach to generating a cutting path for the volumetric resection of tissue using a computer-guided laser scalpel. A soft tissue ablation simulator is developed and used in conjunction with an optimization routine to select parameters which maximize the total resection of target tissue while minimizing the damage to surrounding tissue. The simulator predicts the ablative properties of tissue from an interrogation cut for tuning and simulates the removal of a tumorous tissue embedded on the surface of healthy tissue using a laser scalpel. We demonstrate the ability to control depth and smoothness of cut using genetic algorithms to optimize the ablation parameters and cutting path. The laser power level, cutting rate and spacing between cuts are optimized over multiple surface cuts to achieve the desired resection volumes.

PATHS groundwater hydrologic model

Energy Technology Data Exchange (ETDEWEB)

Nelson, R.W.; Schur, J.A.

1980-04-01

A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

Long open-path measurements of greenhouse gases in air using near-infrared Fourier transform spectroscopy

Science.gov (United States)

Griffith, David W. T.; Pöhler, Denis; Schmitt, Stefan; Hammer, Samuel; Vardag, Sanam N.; Platt, Ulrich

2018-03-01

In complex and urban environments, atmospheric trace gas composition is highly variable in time and space. Point measurement techniques for trace gases with in situ instruments are well established and accurate, but do not provide spatial averaging to compare against developing high-resolution atmospheric models of composition and meteorology with resolutions of the order of a kilometre. Open-path measurement techniques provide path average concentrations and spatial averaging which, if sufficiently accurate, may be better suited to assessment and interpretation with such models. Open-path Fourier transform spectroscopy (FTS) in the mid-infrared region, and differential optical absorption spectroscopy (DOAS) in the UV and visible, have been used for many years for open-path spectroscopic measurements of selected species in both clean air and in polluted environments. Near infrared instrumentation allows measurements over longer paths than mid-infrared FTS for species such as greenhouse gases which are not easily accessible to DOAS.In this pilot study we present the first open-path near-infrared (4000-10 000 cm-1, 1.0-2.5 µm) FTS measurements of CO2, CH4, O2, H2O and HDO over a 1.5 km path in urban Heidelberg, Germany. We describe the construction of the open-path FTS system, the analysis of the collected spectra, several measures of precision and accuracy of the measurements, and the results a four-month trial measurement period in July-November 2014. The open-path measurements are compared to calibrated in situ measurements made at one end of the open path. We observe significant differences of the order of a few ppm for CO2 and a few tens of ppb for CH4 between the open-path and point measurements which are 2 to 4 times the measurement repeatability, but we cannot unequivocally assign the differences to specific local sources or sinks. We conclude that open-path FTS may provide a valuable new tool for investigations of atmospheric trace gas composition in

Springback effects during single point incremental forming: Optimization of the tool path

Science.gov (United States)

Giraud-Moreau, Laurence; Belchior, Jérémy; Lafon, Pascal; Lotoing, Lionel; Cherouat, Abel; Courtielle, Eric; Guines, Dominique; Maurine, Patrick

2018-05-01

Incremental sheet forming is an emerging process to manufacture sheet metal parts. This process is more flexible than conventional one and well suited for small batch production or prototyping. During the process, the sheet metal blank is clamped by a blank-holder and a small-size smooth-end hemispherical tool moves along a user-specified path to deform the sheet incrementally. Classical three-axis CNC milling machines, dedicated structure or serial robots can be used to perform the forming operation. Whatever the considered machine, large deviations between the theoretical shape and the real shape can be observed after the part unclamping. These deviations are due to both the lack of stiffness of the machine and residual stresses in the part at the end of the forming stage. In this paper, an optimization strategy of the tool path is proposed in order to minimize the elastic springback induced by residual stresses after unclamping. A finite element model of the SPIF process allowing the shape prediction of the formed part with a good accuracy is defined. This model, based on appropriated assumptions, leads to calculation times which remain compatible with an optimization procedure. The proposed optimization method is based on an iterative correction of the tool path. The efficiency of the method is shown by an improvement of the final shape.

A Vision-Aided 3D Path Teaching Method before Narrow Butt Joint Welding.

Science.gov (United States)

Zeng, Jinle; Chang, Baohua; Du, Dong; Peng, Guodong; Chang, Shuhe; Hong, Yuxiang; Wang, Li; Shan, Jiguo

2017-05-11

For better welding quality, accurate path teaching for actuators must be achieved before welding. Due to machining errors, assembly errors, deformations, etc., the actual groove position may be different from the predetermined path. Therefore, it is significant to recognize the actual groove position using machine vision methods and perform an accurate path teaching process. However, during the teaching process of a narrow butt joint, the existing machine vision methods may fail because of poor adaptability, low resolution, and lack of 3D information. This paper proposes a 3D path teaching method for narrow butt joint welding. This method obtains two kinds of visual information nearly at the same time, namely 2D pixel coordinates of the groove in uniform lighting condition and 3D point cloud data of the workpiece surface in cross-line laser lighting condition. The 3D position and pose between the welding torch and groove can be calculated after information fusion. The image resolution can reach 12.5 μm. Experiments are carried out at an actuator speed of 2300 mm/min and groove width of less than 0.1 mm. The results show that this method is suitable for groove recognition before narrow butt joint welding and can be applied in path teaching fields of 3D complex components.

A critical review of predictive models for the onset of significant void in forced-convection subcooled boiling

International Nuclear Information System (INIS)

Dorra, H.; Lee, S.C.; Bankoff, S.G.

1993-06-01

This predictive models for the onset of significant void (OSV) in forced-convection subcooled boiling are reviewed and compared with extensive data. Three analytical models and seven empirical correlations are considered in this review. These models and correlations are put onto a common basis and are compared, again on a common basis, with a variety of data. The evaluation of their range of validity and applicability under various operating conditions are discussed. The results show that the correlations of Saha-Zuber seems to be the best model to predict OSV in vertical subcooled boiling flow

Modeling and Solving the Train Pathing Problem

Directory of Open Access Journals (Sweden)

Chuen-Yih Chen

2009-04-01

Full Text Available In a railroad system, train pathing is concerned with the assignment of trains to links and tracks, and train timetabling allocates time slots to trains. In this paper, we present an optimization heuristic to solve the train pathing and timetabling problem. This heuristic allows the dwell time of trains in a station or link to be dependent on the assigned tracks. It also allows the minimum clearance time between the trains to depend on their relative status. The heuristic generates a number of alternative paths for each train service in the initialization phase. Then it uses a neighborhood search approach to find good feasible combinations of these paths. A linear program is developed to evaluate the quality of each combination that is encountered. Numerical examples are provided.

Special cases of the quadratic shortest path problem

NARCIS (Netherlands)

Sotirov, Renata; Hu, Hao

2017-01-01

The quadratic shortest path problem (QSPP) is the problem of finding a path with prespecified start vertex s and end vertex t in a digraph such that the sum of weights of arcs and the sum of interaction costs over all pairs of arcs on the path is minimized. We first consider a variant of the QSPP

Differential neural network configuration during human path integration

Science.gov (United States)

Arnold, Aiden E. G. F; Burles, Ford; Bray, Signe; Levy, Richard M.; Iaria, Giuseppe

2014-01-01

Path integration is a fundamental skill for navigation in both humans and animals. Despite recent advances in unraveling the neural basis of path integration in animal models, relatively little is known about how path integration operates at a neural level in humans. Previous attempts to characterize the neural mechanisms used by humans to visually path integrate have suggested a central role of the hippocampus in allowing accurate performance, broadly resembling results from animal data. However, in recent years both the central role of the hippocampus and the perspective that animals and humans share similar neural mechanisms for path integration has come into question. The present study uses a data driven analysis to investigate the neural systems engaged during visual path integration in humans, allowing for an unbiased estimate of neural activity across the entire brain. Our results suggest that humans employ common task control, attention and spatial working memory systems across a frontoparietal network during path integration. However, individuals differed in how these systems are configured into functional networks. High performing individuals were found to more broadly express spatial working memory systems in prefrontal cortex, while low performing individuals engaged an allocentric memory system based primarily in the medial occipito-temporal region. These findings suggest that visual path integration in humans over short distances can operate through a spatial working memory system engaging primarily the prefrontal cortex and that the differential configuration of memory systems recruited by task control networks may help explain individual biases in spatial learning strategies. PMID:24808849

Using Multiple Methods to teach ASTR 101 students the Path of the Sun and Shadows

Science.gov (United States)

D'Cruz, Noella L.

2015-01-01

It seems surprising that non-science major introductory astronomy students find the daily path of the Sun and shadows created by the Sun challenging to learn even though both can be easily observed (provided students do not look directly at the Sun). In order for our students to master the relevant concepts, we have usually used lecture, a lecture tutorial (from Prather, et al.) followed by think-pair-share questions, a planetarium presentation and an animation from the Nebraska Astronomy Applet Project to teach these topics. We cover these topics in a lecture-only, one semester introductory astronomy course at Joliet Junior College. Feedback from our Spring 2014 students indicated that the planetarium presentation was the most helpful in learning the path of the Sun while none of the four teaching methods was helpful when learning about shadows cast by the Sun. Our students did not find the lecture tutorial to be much help even though such tutorials have been proven to promote deep conceptual change. In Fall 2014, we continued to use these four methods, but we modified how we teach both topics so our students could gain more from the tutorial. We hoped our modifications would cause students to have a better overall grasp of the concepts. After our regular lecture, we gave a shorter than usual planetarium presentation on the path of the Sun and we asked students to work through a shadow activity from Project Astro materials. Then students completed the lecture tutorial and some think-pair-share questions. After this, we asked students to predict the Sun's path on certain days of the year and we used the planetarium projector to show them how well their predictions matched up. We ended our coverage of these topics by asking students a few more think-pair-share questions. In our poster, we will present our approach to teaching these topics in Fall 2014, how our Fall 2014 students feel about our teaching strategies and how they fared on related test questions.

A Key Event Path Analysis Approach for Integrated Systems

Directory of Open Access Journals (Sweden)

Jingjing Liao

2012-01-01

Full Text Available By studying the key event paths of probabilistic event structure graphs (PESGs, a key event path analysis approach for integrated system models is proposed. According to translation rules concluded from integrated system architecture descriptions, the corresponding PESGs are constructed from the colored Petri Net (CPN models. Then the definitions of cycle event paths, sequence event paths, and key event paths are given. Whereafter based on the statistic results after the simulation of CPN models, key event paths are found out by the sensitive analysis approach. This approach focuses on the logic structures of CPN models, which is reliable and could be the basis of structured analysis for discrete event systems. An example of radar model is given to characterize the application of this approach, and the results are worthy of trust.

Finding significantly connected voxels based on histograms of connection strengths

DEFF Research Database (Denmark)

Kasenburg, Niklas; Pedersen, Morten Vester; Darkner, Sune

2016-01-01

We explore a new approach for structural connectivity based segmentations of subcortical brain regions. Connectivity based segmentations are usually based on fibre connections from a seed region to predefined target regions. We present a method for finding significantly connected voxels based...... on the distribution of connection strengths. Paths from seed voxels to all voxels in a target region are obtained from a shortest-path tractography. For each seed voxel we approximate the distribution with a histogram of path scores. We hypothesise that the majority of estimated connections are false-positives...... and that their connection strength is distributed differently from true-positive connections. Therefore, an empirical null-distribution is defined for each target region as the average normalized histogram over all voxels in the seed region. Single histograms are then tested against the corresponding null...

Mission-directed path planning for planetary rover exploration

Science.gov (United States)

Tompkins, Paul

2005-07-01

Robotic rovers uniquely benefit planetary exploration---they enable regional exploration with the precision of in-situ measurements, a combination impossible from an orbiting spacecraft or fixed lander. Mission planning for planetary rover exploration currently utilizes sophisticated software for activity planning and scheduling, but simplified path planning and execution approaches tailored for localized operations to individual targets. This approach is insufficient for the investigation of multiple, regionally distributed targets in a single command cycle. Path planning tailored for this task must consider the impact of large scale terrain on power, speed and regional access; the effect of route timing on resource availability; the limitations of finite resource capacity and other operational constraints on vehicle range and timing; and the mutual influence between traverses and upstream and downstream stationary activities. Encapsulating this reasoning in an efficient autonomous planner would allow a rover to continue operating rationally despite significant deviations from an initial plan. This research presents mission-directed path planning that enables an autonomous, strategic reasoning capability for robotic explorers. Planning operates in a space of position, time and energy. Unlike previous hierarchical approaches, it treats these dimensions simultaneously to enable globally-optimal solutions. The approach calls on a near incremental search algorithm designed for planning and re-planning under global constraints, in spaces of higher than two dimensions. Solutions under this method specify routes that avoid terrain obstacles, optimize the collection and use of rechargable energy, satisfy local and global mission constraints, and account for the time and energy of interleaved mission activities. Furthermore, the approach efficiently re-plans in response to updates in vehicle state and world models, and is well suited to online operation aboard a robot

Moderating Effects of Prevention-Focus on the Paths from Two Insecure Attachment Dimensions to Depression.

Science.gov (United States)

Lee, Dong-Gwi; Park, Jae Joon; Bae, Byeong Hoon; Lim, Hyun-Woo

2018-04-03

The present study investigated the moderating effects of prevention-focus on the paths from the dimensions of insecure attachment (attachment avoidance and attachment anxiety) to depression. Two hundred twenty eight Korean college students completed the Experience in Close Relationship - Revised Scale; the Regulatory Focus Strategies Scale; and the Center for Epidemiologic Studies Depression Scale. Results revealed a significant moderating effect for prevention-focus on the path from attachment avoidance to depression, but not on the path from attachment anxiety to depression. They further suggest that different interventions are needed for different combinations of persons' insecure attachment dimensions and levels of prevention-focus. Counseling implications and suggestions for future research are discussed.

Predictive labeling with dependency pairs using SAT

NARCIS (Netherlands)

Koprowski, A.; Middeldorp, A.; Pfenning, F.

2007-01-01

This paper combines predictive labeling with dependency pairs and reports on its implementation. Our starting point is the method of proving termination of rewrite systems using semantic labeling with infinite models in combination with lexicographic path orders. We replace semantic labeling with

[Glide path management of rotary nickel-titanium instruments in simulated root canals].

Science.gov (United States)

Han, Y; Bai, Y H; Hou, X M

2018-02-18

To compare the shaping ability of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 with that of PathFile and stainless steel K-file hand instruments in simulated root canals. A total of 60 simulated resin blocks were divided randomly into five groups (n=12), each group prepared with each instrument, respectively. Preparation time was recorded. Pre- and post-operative images were obtained using a scanner and superimposed using Photoshop. The material removal from the inner and outer canal walls beginning from 0 mm at the end point of the canal were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the One-Way ANOVA at a significance level of P0.05). The removal of resin from the outer wall at the apical portion was significantly lower for HyFlex EDM Glidepath File than for ProGlider (PEDM Glidepath File the second most, and the other 3 groups among the same levels. As far as the centering ability was concerned, at the apical portion, HyFlex EDM Glidepath File was the best, ProGlider the second best, no significant difference identified among the other 3 groups. At the curvature portion, ProGlider and HyFlex EDM Glidepath File were the best, PathFile the second, RaCe ISO 10 the third, the worst was the SS K-file. At the straight portion, the difference amongt the 5 groups was not significant. The shaping abilities of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 were better or comparable to that of PathFile, while the preparation time for ProGlider reduced significantly, and HyFlex EDM Glidepath File and RaCe ISO 10 removed significantly more resin at the straight portion of the canal.

The Long and Winding Road: Grades, Psychological Disengagement and Motivation among Female Students in (Non-)Traditional Career Paths

Science.gov (United States)

Rinfret, Natalie; Tougas, Francine; Beaton, Ann M.; Laplante, Joelle; Ngo Manguelle, Christiane; Lagacé, Marie Claude

2014-01-01

The purpose of this study was to evaluate the links between grades, psychological disengagement mechanisms (discounting evaluative feedback and devaluing school), and motivation among female students in traditional and non-traditional career paths. We predicted that the association between grades and discounting is affected by the importance of…

Teaching quantum physics by the sum over paths approach and GeoGebra simulations

International Nuclear Information System (INIS)

Malgieri, M; Onorato, P; De Ambrosis, A

2014-01-01

We present a research-based teaching sequence in introductory quantum physics using the Feynman sum over paths approach. Our reconstruction avoids the historical pathway, and starts by reconsidering optics from the standpoint of the quantum nature of light, analysing both traditional and modern experiments. The core of our educational path lies in the treatment of conceptual and epistemological themes, peculiar of quantum theory, based on evidence from quantum optics, such as the single photon Mach–Zehnder and Zhou–Wang–Mandel experiments. The sequence is supported by a collection of interactive simulations, realized in the open source GeoGebra environment, which we used to assist students in learning the basics of the method, and help them explore the proposed experimental situations as modeled in the sum over paths perspective. We tested our approach in the context of a post-graduate training course for pre-service physics teachers; according to the data we collected, student teachers displayed a greatly improved understanding of conceptual issues, and acquired significant abilities in using the sum over path method for problem solving. (paper)

Comparison of tool feed influence in CNC polishing between a novel circular-random path and other pseudo-random paths.

Science.gov (United States)

Takizawa, Ken; Beaucamp, Anthony

2017-09-18

A new category of circular pseudo-random paths is proposed in order to suppress repetitive patterns and improve surface waviness on ultra-precision polished surfaces. Random paths in prior research had many corners, therefore deceleration of the polishing tool affected the surface waviness. The new random path can suppress velocity changes of the polishing tool and thus restrict degradation of the surface waviness, making it suitable for applications with stringent mid-spatial-frequency requirements such as photomask blanks for EUV lithography.

Communication: Predictive partial linearized path integral simulation of condensed phase electron transfer dynamics

International Nuclear Information System (INIS)

Huo, Pengfei; Miller, Thomas F. III; Coker, David F.

2013-01-01

A partial linearized path integral approach is used to calculate the condensed phase electron transfer (ET) rate by directly evaluating the flux-flux/flux-side quantum time correlation functions. We demonstrate for a simple ET model that this approach can reliably capture the transition between non-adiabatic and adiabatic regimes as the electronic coupling is varied, while other commonly used semi-classical methods are less accurate over the broad range of electronic couplings considered. Further, we show that the approach reliably recovers the Marcus turnover as a function of thermodynamic driving force, giving highly accurate rates over four orders of magnitude from the normal to the inverted regimes. We also demonstrate that the approach yields accurate rate estimates over five orders of magnitude of inverse temperature. Finally, the approach outlined here accurately captures the electronic coherence in the flux-flux correlation function that is responsible for the decreased rate in the inverted regime

Evaluation of Calcine Disposition Path Forward

International Nuclear Information System (INIS)

Birrer, S.A.; Heiser, M.B.

2003-01-01

This document describes an evaluation of the baseline and two alternative disposition paths for the final disposition of the calcine wastes stored at the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory. The pathways are evaluated against a prescribed set of criteria and a recommendation is made for the path forward

Path probabilities of continuous time random walks

International Nuclear Information System (INIS)

Eule, Stephan; Friedrich, Rudolf

2014-01-01

Employing the path integral formulation of a broad class of anomalous diffusion processes, we derive the exact relations for the path probability densities of these processes. In particular, we obtain a closed analytical solution for the path probability distribution of a Continuous Time Random Walk (CTRW) process. This solution is given in terms of its waiting time distribution and short time propagator of the corresponding random walk as a solution of a Dyson equation. Applying our analytical solution we derive generalized Feynman–Kac formulae. (paper)

Significant change of predictions related to the future of nuclear power

International Nuclear Information System (INIS)

Dumitrache, Ion

2002-01-01

During the last two decades of the 20th century, nuclear power contribution increased slowly in the world. This trend was mainly determined by the commissioning of new nuclear power plants, NPP, in the non-developed countries, except for Japan and South Korea. Almost all the forecasts offered the image of the stagnant nuclear power business. Sweden, Germany, Holland and Belgium Governments made clear the intention to stop the production of electricity based on fission. Recently, despite the negative effects on nuclear power of the terrorism events of September 11, 2001, the predictions related to the nuclear power future become much more optimistic. USA, Japan, South Korea and Canada made clear that new NPPs will offer their significant electricity contribution several decades, even after years 2020-2030. Moreover, several old NPP from USA obtained the license for an additional 20 years period of operation. The analysis indicated that most of the existing NPP in USA may increase the level of the maximum global power defined by the initial design. In the European Union the situation is much more complicated. About 35% of the electricity is based now on fission. Several countries, like Sweden and Germany, maintain the position of phasing out the NPPs, as soon as the licensed life-time is over. Finland decided to build a new power plant. France is very favorable to nuclear power, but does not need more energy. In the UK several very old NPP will be shut down, and companies like BNFL and British Energy intend to build new NPP, based on Westinghouse or AECL-Canada advanced reactors. Switzerland and Spain are favorable to the future use of nuclear power. In the eastern part of Europe, almost all the countries intend to base their electricity production on coal, fission, hydro and gas, nuclear contribution being significant. The most impressive increases of nuclear power output are related to Asia; in China, from 2.2 Gwe in 1999, to 18.7 Gwe in 2020, reference case, or 10

Path-integral approach to resonant electron-molecule scattering

International Nuclear Information System (INIS)

Winterstetter, M.; Domcke, W.

1993-01-01

A path-integral formulation of resonant electron-molecule scattering is developed within the framework of the projection-operator formalism of scattering theory. The formation and decay of resonances is treated in real time as a quantum-mechanical electronic-tunneling process, modified by the coupling of the electronic motion with the nuclear degrees of freedom. It is shown that the electronic continuum can be summed over in the path-integral formulation, resulting formally in the path integral for an effective two-state system with coupling to vibrations. The harmonic-oscillator approximation is adopted for the vibrational motion in the present work. Approximation methods are introduced which render the numerical evaluation of the sum over paths feasible for up to ∼10 3 elementary time slices. The theory is numerically realized for simple but nontrivial models representing the 2 Π g d-wave shape resonance in e - +N 2 collisions and the 2 Σ u + p-wave shape resonance in e - +H 2 collisions, respectively. The accuracy of the path-integral results is assessed by comparison with exact numerical reference data for these models. The essential virtue of the path-integral approach is the fact that the computational effort scales at most linearly with the number of vibrational degrees of freedom. The path-integral method is thus well suited to treat electron collisions with polyatomic molecules and molecular aggregates

Non-invasive prediction of hemodynamically significant coronary artery stenoses by contrast density difference in coronary CT angiography

Energy Technology Data Exchange (ETDEWEB)

Hell, Michaela M., E-mail: michaela.hell@uk-erlangen.de [Department of Cardiology, University of Erlangen (Germany); Dey, Damini [Department of Biomedical Sciences, Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Taper Building, Room A238, 8700 Beverly Boulevard, Los Angeles, CA 90048 (United States); Marwan, Mohamed; Achenbach, Stephan; Schmid, Jasmin; Schuhbaeck, Annika [Department of Cardiology, University of Erlangen (Germany)

2015-08-15

Highlights: • Overestimation of coronary lesions by coronary computed tomography angiography and subsequent unnecessary invasive coronary angiography and revascularization is a concern. • Differences in plaque characteristics and contrast density difference between hemodynamically significant and non-significant stenoses, as defined by invasive fractional flow reserve, were assessed. • At a threshold of ≥24%, contrast density difference predicted hemodynamically significant lesions with a specificity of 75%, sensitivity of 33%, PPV of 35% and NPV of 73%. • The determination of contrast density difference required less time than transluminal attenuation gradient measurement. - Abstract: Objectives: Coronary computed tomography angiography (CTA) allows the detection of obstructive coronary artery disease. However, its ability to predict the hemodynamic significance of stenoses is limited. We assessed differences in plaque characteristics and contrast density difference between hemodynamically significant and non-significant stenoses, as defined by invasive fractional flow reserve (FFR). Methods: Lesion characteristics of 59 consecutive patients (72 lesions) in whom invasive FFR was performed in at least one coronary artery with moderate to high-grade stenoses in coronary CTA were evaluated by two experienced readers. Coronary CTA data sets were acquired on a second-generation dual-source CT scanner using retrospectively ECG-gated spiral acquisition or prospectively ECG-triggered axial acquisition mode. Plaque volume and composition (non-calcified, calcified), remodeling index as well as contrast density difference (defined as the percentage decline in luminal CT attenuation/cross-sectional area over the lesion) were assessed using a semi-automatic software tool (Autoplaq). Additionally, the transluminal attenuation gradient (defined as the linear regression coefficient between intraluminal CT attenuation and length from the ostium) was determined

Filtering and prediction

CERN Document Server

Fristedt, B; Krylov, N

2007-01-01

Filtering and prediction is about observing moving objects when the observations are corrupted by random errors. The main focus is then on filtering out the errors and extracting from the observations the most precise information about the object, which itself may or may not be moving in a somewhat random fashion. Next comes the prediction step where, using information about the past behavior of the object, one tries to predict its future path. The first three chapters of the book deal with discrete probability spaces, random variables, conditioning, Markov chains, and filtering of discrete Markov chains. The next three chapters deal with the more sophisticated notions of conditioning in nondiscrete situations, filtering of continuous-space Markov chains, and of Wiener process. Filtering and prediction of stationary sequences is discussed in the last two chapters. The authors believe that they have succeeded in presenting necessary ideas in an elementary manner without sacrificing the rigor too much. Such rig...

A Path-Independent Forming Limit Criterion for Stamping Simulations

International Nuclear Information System (INIS)

Zhu Xinhai; Chappuis, Laurent; Xia, Z. Cedric

2005-01-01

Forming Limit Diagram (FLD) has been proved to be a powerful tool for assessing necking failures in sheet metal forming analysis for majority of stamping operations over the last three decades. However, experimental evidence and theoretical analysis suggest that its applications are limited to linear or almost linear strain paths during its deformation history. Abrupt changes or even gradual deviations from linear strain-paths will shift forming limit curves from their original values, a situation that occurs in vast majority of sequential stamping operations such as where the drawing process is followed by flanging and re-strike processes. Various forming limit models have been put forward recently to provide remedies for the problem, noticeably stress-based and strain gradient-based forming limit criteria. This study presents an alternative path-independent forming limit criterion. Instead of traditional Forming Limit Diagrams (FLD) which are constructed in terms of major - minor principal strains throughout deformation history, the new criterion defines a critical effective strain ε-bar* as the limit strain for necking, and it is shown that ε-bar* can be expressed as a function of current strain rate state and material work hardening properties, without the need of explicitly considering strain-path effects. It is given by ε-bar* = f(β, k, n) where β = (dε 2 /dε 1 ) at current deformation state, and k and n are material strain hardening parameters if a power law is assumed. The analysis is built upon previous work by Storen and Rice [1975] and Zhu et al [2002] with the incorporation of anisotropic yield models such as Hill'48 for quadratic orthotropic yield and Hill'79 for non-quadratic orthotropic yield. Effects of anisotropic parameters such as R-values and exponent n-values on necking are investigated in detail for a variety of strain paths. Results predicted according to current analysis are compared against experimental data gathered from literature

Quadcopter Path Following Control Design Using Output Feedback with Command Generator Tracker LOS Based At Square Path

Science.gov (United States)

Nugraha, A. T.; Agustinah, T.

2018-01-01

Quadcopter an unstable system, underactuated and nonlinear in quadcopter control research developments become an important focus of attention. In this study, following the path control method for position on the X and Y axis, used structure-Generator Tracker Command (CGT) is tested. Attitude control and position feedback quadcopter is compared using the optimal output. The addition of the H∞ performance optimal output feedback control is used to maintain the stability and robustness of quadcopter. Iterative numerical techniques Linear Matrix Inequality (LMI) is used to find the gain controller. The following path control problems is solved using the method of LQ regulators with output feedback. Simulations show that the control system can follow the paths that have been defined in the form of a reference signal square shape. The result of the simulation suggest that the method which used can bring the yaw angle at the expected value algorithm. Quadcopter can do automatically following path with cross track error mean X=0.5 m and Y=0.2 m.

Bosonic path integral for spin-1/2 particles

International Nuclear Information System (INIS)

Jacobson, T.

1989-01-01

The 3D Dirac propagator is expressed as a path integral over curves of commuting two-component spinors. This is related to the path integral recently employed by Polyakov to demonstrate Fermi-Bose transmutation for solitons in the gauged CP 1 model with Chern-Simons term. Several difficulties concerning the latter path integral are identified and corrected from our point of view. (orig.)

Forces in Motzkin paths in a wedge

International Nuclear Information System (INIS)

Janse van Rensburg, E J

2006-01-01

Entropic forces in models of Motzkin paths in a wedge geometry are considered as models of forces in polymers in confined geometries. A Motzkin path in the square lattice is a path from the origin to a point in the line Y = X while it never visits sites below this line, and it is constrained to give unit length steps only in the north and east directions and steps of length √2 in the north-east direction. Motzkin path models may be generalized to ensembles of NE-oriented paths above the line Y = rX, where r > 0 is an irrational number. These are paths giving east, north and north-east steps from the origin in the square lattice, and confined to the r-wedge formed by the Y-axis and the line Y = rX. The generating function g r of these paths is not known, but if r > 1, then I determine its radius of convergence to be t r = min (r-1)/r≤y≤r/(r+1) [y y (1-r(1-y)) 1-r(1-y) (r(1-y)-y) r(1-y)-y ] and if r is an element of (0, 1), then t r = 1/3. The entropic force the path exerts on the line Y rX may be computed from this. An asymptotic expression for the force for large values of r is given by F(r) = log(2r)/r 2 - (1+2log(2r))/2r 3 + O (log(2r)/r 4 ). In terms of the vertex angle α of the r-wedge, the moment of the force about the origin has leading terms F(α) log(2/α) - (α/2)(1+2log(2/α)) + O(α 2 log(2/α)) as α → 0 + and F(α) = 0 if α is element of [π/4, π/2]. Moreover, numerical integration of the force shows that the total work done by closing the wedge is 1.085 07... lattice units. An alternative ensemble of NE-oriented paths may be defined by slightly changing the generating function g r . In this model, it is possible to determine closed-form expressions for the limiting free energy and the force. The leading term in an asymptotic expansions for this force agrees with the leading term in the asymptotic expansion of the above model, and the subleading term only differs by a factor of 2

A moderated mediated path analysis of factors influencing student performance on a standardized high-stakes science test

Science.gov (United States)

Pelkey, Ramona K.

Gender, ethnicity, family economic status, reading score, mathematics score, and number of science semesters successfully completed were examined for their contributory role to a student's science score on a high-stakes, high school exit examination. Path analysis and analysis of variance procedures were used to quantify each variable's influence on science score. Gender, ethnicity, and family economic status were found to be moderators while reading proved to mediate within the model. The path model was created using a calibration sample and cross-validated using a hold-out validation sample. Bootstrapping was used to verify the goodness of fit of the model. A predictive equation explained 66% (R2 = .66) of the variance in observed TAKS science score.

A middle path for electricity options and sustainable development

International Nuclear Information System (INIS)

Mills, J.I.; Herring, J.S.

1994-01-01

In a landmark article in Foreign Affairs in October 1976, Amory Lovins presented his vision of two vastly different and seemingly irreconcilable paths that energy provision might take into the future. One path was a ''hard'' path, characterized by extensive development of large, capital-intensive centralized electrical generating facilities and their peripherals, designed with little consideration given to the matching of these facilities to the requirements of the end-use needs. The second, ''soft'' path was characterized by energy technologies that are diverse, operate on renewable energy flows, are relatively simple, less capital-intensive, and matched in scale and energy quality to end-use needs. One of the most controversial arguments in the Lovins' paper was that the ''hard'' and ''soft'' paths are culturally and institutionally antagonistic. In retrospect, it seems this argument was self-fulfilling, for the history of the energy debate throughout the developed world since the appearance of the Lovins' article has been marked by an either-or antagonism that has left little room for serious discussion of a ''middle-path.'' In this paper, we argue that ''middle-path,'' paved with elements of both the soft and hard, is especially suited for developing countries, since they do not now carry the burden of an existing and extensive ''hard path'' energy infrastructure

Computing Diffeomorphic Paths for Large Motion Interpolation.

Science.gov (United States)

Seo, Dohyung; Jeffrey, Ho; Vemuri, Baba C

2013-06-01

In this paper, we introduce a novel framework for computing a path of diffeomorphisms between a pair of input diffeomorphisms. Direct computation of a geodesic path on the space of diffeomorphisms Diff (Ω) is difficult, and it can be attributed mainly to the infinite dimensionality of Diff (Ω). Our proposed framework, to some degree, bypasses this difficulty using the quotient map of Diff (Ω) to the quotient space Diff ( M )/ Diff ( M ) μ obtained by quotienting out the subgroup of volume-preserving diffeomorphisms Diff ( M ) μ . This quotient space was recently identified as the unit sphere in a Hilbert space in mathematics literature, a space with well-known geometric properties. Our framework leverages this recent result by computing the diffeomorphic path in two stages. First, we project the given diffeomorphism pair onto this sphere and then compute the geodesic path between these projected points. Second, we lift the geodesic on the sphere back to the space of diffeomerphisms, by solving a quadratic programming problem with bilinear constraints using the augmented Lagrangian technique with penalty terms. In this way, we can estimate the path of diffeomorphisms, first, staying in the space of diffeomorphisms, and second, preserving shapes/volumes in the deformed images along the path as much as possible. We have applied our framework to interpolate intermediate frames of frame-sub-sampled video sequences. In the reported experiments, our approach compares favorably with the popular Large Deformation Diffeomorphic Metric Mapping framework (LDDMM).

Path integral discussion for Smorodinsky-Winternitz potentials. Pt. 1

International Nuclear Information System (INIS)

Grosche, C.; Pogosyan, G.S.; Sissakian, A.N.

1994-02-01

Path integral formulations for the Smorodinsky-Winternitz potentials in two- and three-dimensional Euclidean space are presented. We mention all coordinate systems which separate the Smorodinsky-Winternitz potentials and state the corresponding path integral formulations. Whereas in many coordinate systems an explicit path integralformulation is not possible, we list in all soluble cases the path integral evaluations explicity in terms of the propagators and the spectral expansions into the wave-functions. (orig.)

Preparation and tomographic reconstruction of an arbitrary single-photon path qubit

International Nuclear Information System (INIS)

Baek, So-Young; Kim, Yoon-Ho

2011-01-01

We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. The arbitrary single-photon path qubit is prepared losslessly by passing the heralded single-photon state from spontaneous parametric down-conversion through variable beam splitter. Quantum state tomography of the single-photon path qubit is implemented by introducing path-projection measurements based on the first-order single-photon quantum interference. Using the state preparation and path-projection measurements methods for the single-photon path qubit, we demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity. -- Highlights: → We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. → We implement path-projection measurements based on the first-order single-photon quantum interference. → We demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity.

Walking paths to and from a goal differ: on the role of bearing angle in the formation of human locomotion paths.

Directory of Open Access Journals (Sweden)

Manish Sreenivasa

Full Text Available The path that humans take while walking to a goal is the result of a cognitive process modulated by the perception of the environment and physiological constraints. The path shape and timing implicitly embeds aspects of the architecture behind this process. Here, locomotion paths were investigated during a simple task of walking to and from a goal, by looking at the evolution of the position of the human on a horizontal (x,y plane. We found that the path while walking to a goal was not the same as that while returning from it. Forward-return paths were systematically separated by 0.5-1.9m, or about 5% of the goal distance. We show that this path separation occurs as a consequence of anticipating the desired body orientation at the goal while keeping the target in view. The magnitude of this separation was strongly influenced by the bearing angle (difference between body orientation and angle to goal and the final orientation imposed at the goal. This phenomenon highlights the impact of a trade-off between a directional perceptual apparatus-eyes in the head on the shoulders-and and physiological limitations, in the formation of human locomotion paths. Our results give an insight into the influence of environmental and perceptual variables on human locomotion and provide a basis for further mathematical study of these mechanisms.

Path integral representations on the complex sphere

International Nuclear Information System (INIS)

Grosche, C.

2007-08-01

In this paper we discuss the path integral representations for the coordinate systems on the complex sphere S 3C . The Schroedinger equation, respectively the path integral, separates in exactly 21 orthogonal coordinate systems. We enumerate these coordinate systems and we are able to present the path integral representations explicitly in the majority of the cases. In each solution the expansion into the wave-functions is stated. Also, the kernel and the corresponding Green function can be stated in closed form in terms of the invariant distance on the sphere, respectively on the hyperboloid. (orig.)

Prediction on the Enhancement of the Impact Sound Insulation to a Floating Floor with Resilient Interlayer

Science.gov (United States)

Huang, Xianfeng; Meng, Yao; Huang, Riming

2017-10-01

This paper describes a theoretical method for predicting the improvement of the impact sound insulation to a floating floor with the resilient interlayer. Statistical energy analysis (SEA) model, which is skilful in calculating the floor impact sound, is set up for calculating the reduction in impact sound pressure level in downstairs room. The sound transmission paths which include direct path and flanking paths are analyzed to find the dominant one; the factors that affect impact sound reduction for a floating floor are explored. Then, the impact sound level in downstairs room is determined and comparisons between predicted and measured data are conducted. It is indicated that for the impact sound transmission across a floating floor, the flanking path impact sound level contribute tiny influence on overall sound level in downstairs room, and a floating floor with low stiffness interlayer exhibits favorable sound insulation on direct path. The SEA approach applies to the floating floors with resilient interlayers, which are experimentally verified, provides a guidance in sound insulation design.

Short communication: Genetic lag represents commercial herd genetic merit more accurately than the 4-path selection model.

Science.gov (United States)

Dechow, C D; Rogers, G W

2018-05-01

Expectation of genetic merit in commercial dairy herds is routinely estimated using a 4-path genetic selection model that was derived for a closed population, but commercial herds using artificial insemination sires are not closed. The 4-path model also predicts a higher rate of genetic progress in elite herds that provide artificial insemination sires than in commercial herds that use such sires, which counters other theoretical assumptions and observations of realized genetic responses. The aim of this work is to clarify whether genetic merit in commercial herds is more accurately reflected under the assumptions of the 4-path genetic response formula or by a genetic lag formula. We demonstrate by tracing the transmission of genetic merit from parents to offspring that the rate of genetic progress in commercial dairy farms is expected to be the same as that in the genetic nucleus. The lag in genetic merit between the nucleus and commercial farms is a function of sire and dam generation interval, the rate of genetic progress in elite artificial insemination herds, and genetic merit of sires and dams. To predict how strategies such as the use of young versus daughter-proven sires, culling heifers following genomic testing, or selective use of sexed semen will alter genetic merit in commercial herds, genetic merit expectations for commercial herds should be modeled using genetic lag expectations. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Social network analysis using k-Path centrality method

Science.gov (United States)

Taniarza, Natya; Adiwijaya; Maharani, Warih

2018-03-01

k-Path centrality is deemed as one of the effective methods to be applied in centrality measurement in which the influential node is estimated as the node that is being passed by information path frequently. Regarding this, k-Path centrality has been employed in the analysis of this paper specifically by adapting random-algorithm approach in order to: (1) determine the influential user’s ranking in a social media Twitter; and (2) ascertain the influence of parameter α in the numeration of k-Path centrality. According to the analysis, the findings showed that the method of k-Path centrality with random-algorithm approach can be used to determine user’s ranking which influences in the dissemination of information in Twitter. Furthermore, the findings also showed that parameter α influenced the duration and the ranking results: the less the α value, the longer the duration, yet the ranking results were more stable.

Neonatal Nutrition Predicts Energy Balance in Young Adults Born Preterm at Very Low Birth Weight

Directory of Open Access Journals (Sweden)

Hanna-Maria Matinolli

2017-11-01

Full Text Available Epidemiological studies and animal models suggest that early postnatal nutrition and growth can influence adult health. However, few human studies have objective recordings of early nutrient intake. We studied whether nutrient intake and growth during the first 9 weeks after preterm birth with very low birth weight (VLBW, <1500 g predict total energy intake, resting energy expenditure (REE, physical activity and food preferences in young adulthood. We collected daily nutritional intakes and weights during the initial hospital stay from hospital records for 127 unimpaired VLBW participants. At an average age 22.5 years, they completed a three-day food record and a physical activity questionnaire and underwent measurements of body composition (dual X-ray absorptiometry; n = 115 with adequate data and REE (n = 92 with adequate data. We used linear regression and path analysis to investigate associations between neonatal nutrient intake and adult outcomes. Higher energy, protein and fat intakes during the first three weeks of life predicted lower relative (=per unit lean body mass energy intake and relative REE in adulthood, independent of other pre- and neonatal factors. In path analysis, total effects of early nutrition and growth on relative energy intake were mostly explained by direct effects of early life nutrition. A path mediated by early growth reached statistical significance only for protein intake. There were no associations of neonatal intakes with physical activity or food preferences in adulthood. As a conclusion, higher intake of energy and nutrients during first three weeks of life of VLBW infants predicts energy balance after 20 years. This association is partly mediated through postnatal growth.

Fractal analysis of crack paths in Al2O3-TiC-4%Co composites

Institute of Scientific and Technical Information of China (English)

LI Jing; YIN Yan-sheng; LIU Ying-cai; MA Lai-peng

2006-01-01

Al2O3-TiC-4%Co(volume fraction) composites(ATC) with high toughness (7.8±0.8 MPa·m1/2) and strength (782±60 MPa) were fabricated. In comparison with Al2O3-TiC composites(AT), the fracture toughness was significantly improved by 60%. The crack paths, generated by Vickers indentation on the polished surfaces of both composites, were analyzed from a fractal point of view to distinguish the possible toughening mechanisms involved. Quantitative evaluation of indentation cracks indicates that the crack deflection plays a more effective role. Cracks of the ATC composites show higher deflection angles and more deflections along the path. ATC composites present higher fractal dimension (D=1.07) than AT composites (D=1.02), which is directly related to the higher fracture toughness. A significant relationship between crack path and toughness is evident: the more irregular the geometry of the crack, the higher the fracture toughness.

Path Planning Method in Multi-obstacle Marine Environment

Science.gov (United States)

Zhang, Jinpeng; Sun, Hanxv

2017-12-01

In this paper, an improved algorithm for particle swarm optimization is proposed for the application of underwater robot in the complex marine environment. Not only did consider to avoid obstacles when path planning, but also considered the current direction and the size effect on the performance of the robot dynamics. The algorithm uses the trunk binary tree structure to construct the path search space and A * heuristic search method is used in the search space to find a evaluation standard path. Then the particle swarm algorithm to optimize the path by adjusting evaluation function, which makes the underwater robot in the current navigation easier to control, and consume less energy.

Lifetime and Path Length of the Virtual Particle

International Nuclear Information System (INIS)

Lyuboshitz, V.L.; Lyuboshitz, V.V.

2005-01-01

The concepts of the lifetime and path length of a virtual particle are introduced. It is shown that, near the mass surface of the real particle, these quantities constitute a 4-vector. At very high energies, the virtual particle can propagate over considerable (even macroscopic) distances. The formulas for the lifetime and path length of an ultrarelativistic virtual electron in the process of bremsstrahlung in the Coulomb field of a nucleus are obtained. The lifetime and path length of the virtual photon at its conversion into an electron-positron pair are discussed. The connection between the path length of the virtual particle and the coherence length (formation length) is analyzed

Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound.

Science.gov (United States)

Zelený, Martin; Straka, Ladislav; Sozinov, Alexei; Heczko, Oleg

2018-05-08

In order to explain the formation of low-temperature phases in stoichiometric Ni 2 MnGa magnetic shape memory alloy, we investigate the phase transformation paths from cubic austenite with Heusler structure to low-symmetry martensitic structures. We used ab initio calculations combined with the generalized solid state nudged elastic band method to determine the minimum energy path and corresponding changes in crystal lattice. The four-, five-, and seven-layered modulated phases of martensite (4O, 10M, and 14M) are built as the relaxed nanotwinned non-modulated (NM) phase. Despite having a total energy larger than the other martensitic phases, the 10M phase will spontaneously form at 0 K, because there is no energy barrier on the path and the energy decreases with a large negative slope. Moreover, a similar negative slope in the beginning of path is found also for the transformation to the 6M premartensite, which appears as a local minimum on the path leading further to 10M martensite. Transformation paths to other structures exhibit more or less significant barriers in the beginning hindering such a transformation from austenite. These findings correspond to experiment and demonstrates that the kinetics of the transformation is decisive for the selection of the particular low-symmetry structure.

Benefit of adaptive FEC in shared backup path protected elastic optical network.

Science.gov (United States)

Guo, Hong; Dai, Hua; Wang, Chao; Li, Yongcheng; Bose, Sanjay K; Shen, Gangxiang

2015-07-27

We apply an adaptive forward error correction (FEC) allocation strategy to an Elastic Optical Network (EON) operated with shared backup path protection (SBPP). To maximize the protected network capacity that can be carried, an Integer Linear Programing (ILP) model and a spectrum window plane (SWP)-based heuristic algorithm are developed. Simulation results show that the FEC coding overhead required by the adaptive FEC scheme is significantly lower than that needed by a fixed FEC allocation strategy resulting in higher network capacity for the adaptive strategy. The adaptive FEC allocation strategy can also significantly outperform the fixed FEC allocation strategy both in terms of the spare capacity redundancy and the average FEC coding overhead needed per optical channel. The proposed heuristic algorithm is efficient and not only performs closer to the ILP model but also does much better than the shortest-path algorithm.

Feasible Path Generation Using Bezier Curves for Car-Like Vehicle

Science.gov (United States)

Latip, Nor Badariyah Abdul; Omar, Rosli

2017-08-01

When planning a collision-free path for an autonomous vehicle, the main criteria that have to be considered are the shortest distance, lower computation time and completeness, i.e. a path can be found if one exists. Besides that, a feasible path for the autonomous vehicle is also crucial to guarantee that the vehicle can reach the target destination considering its kinematic constraints such as non-holonomic and minimum turning radius. In order to address these constraints, Bezier curves is applied. In this paper, Bezier curves are modeled and simulated using Matlab software and the feasibility of the resulting path is analyzed. Bezier curve is derived from a piece-wise linear pre-planned path. It is found that the Bezier curves has the capability of making the planned path feasible and could be embedded in a path planning algorithm for an autonomous vehicle with kinematic constraints. It is concluded that the length of segments of the pre-planned path have to be greater than a nominal value, derived from the vehicle wheelbase, maximum steering angle and maximum speed to ensure the path for the autonomous car is feasible.

A Combination of Terrain Prediction and Correction for Search and Rescue Robot Autonomous Navigation

Directory of Open Access Journals (Sweden)

Yan Guo

2009-09-01

Full Text Available This paper presents a novel two-step autonomous navigation method for search and rescue robot. The algorithm based on the vision is proposed for terrain identification to give a prediction of the safest path with the support vector regression machine (SVRM trained off-line with the texture feature and color features. And correction algorithm of the prediction based the vibration information is developed during the robot traveling, using the judgment function given in the paper. The region with fault prediction will be corrected with the real traversability value and be used to update the SVRM. The experiment demonstrates that this method could help the robot to find the optimal path and be protected from the trap brought from the error between prediction and the real environment.

Points-Based Safe Path Planning of Continuum Robots

Directory of Open Access Journals (Sweden)

Khuram Shahzad

2015-07-01

Full Text Available Continuum robots exhibit great potential in a number of challenging applications where traditional rigid link robots pose certain limitations, e.g., working in unstructured environments. In order to enable the usage of continuum robots in safety-critical applications, such as surgery and nuclear decontamination, it is extremely important to ensure a safe path for the robot's movement. Existing algorithms for continuum robot path planning have certain limitations that need to be addressed. These include the fact that none of the algorithms provide safety assurance parameters and control for path planning. They are computationally expensive, applicable to a specific type of continuum robots, and mostly they do not incorporate design and kinematics constraints. In this paper, we propose a points-based path planning (PoPP algorithm for continuum robots that computes the path by imposing safety constraints and improves upon the limitations of existing approaches. In the algorithm, we exploit the constant curvature-bending property of continuum robots in their path planning process. The algorithm is computationally efficient and provides a good tradeoff between accuracy and efficiency that can be implemented to enable the safety-critical application of continuum robots. This algorithm also provides information regarding path volume and flexibility in movement. Simulation results confirm that the algorithm possesses promising potential for all types of continuum robots (following the constant curvature-bending property. We believe that this effectively balances the desired safety and efficiency requirements.

Minimizing the Carbon Footprint for the Time-Dependent Heterogeneous-Fleet Vehicle Routing Problem with Alternative Paths

Directory of Open Access Journals (Sweden)

Wan-Yu Liu

2014-07-01

Full Text Available Torespondto the reduction of greenhouse gas emissions and global warming, this paper investigates the minimal-carbon-footprint time-dependent heterogeneous-fleet vehicle routing problem with alternative paths (MTHVRPP. This finds a route with the smallestcarbon footprint, instead of the shortestroute distance, which is the conventional approach, to serve a number of customers with a heterogeneous fleet of vehicles in cases wherethere may not be only one path between each pair of customers, and the vehicle speed differs at different times of the day. Inheriting from the NP-hardness of the vehicle routing problem, the MTHVRPP is also NP-hard. This paper further proposes a genetic algorithm (GA to solve this problem. The solution representedbyour GA determines the customer serving ordering of each vehicle type. Then, the capacity check is used to classify multiple routes of each vehicle type, and the path selection determines the detailed paths of each route. Additionally, this paper improves the energy consumption model used for calculating the carbon footprint amount more precisely. Compared with the results without alternative paths, our experimental results show that the alternative path in this experimenthas a significant impact on the experimental results in terms of carbon footprint.

Impact of the magnetic superstorm on March 17-19, 2015 on subpolar HF radio paths: Experiment and modeling

Science.gov (United States)

Blagoveshchensky, D. V.; Maltseva, O. A.; Anishin, M. M.; Sergeeva, M. A.; Rogov, D. D.

2016-09-01

The ionospheric phenomena which significantly influenced radio propagation during March 17-19, 2015 are considered in the study. The data of oblique ionospheric sounding (OIS) were analyzed at six radio paths. These paths are located in the zone of North Siberia in Russia and have different lengths: from 1000 to 5000 km. The results are the following. The magnetic storm drastically changed the character of radio propagation at all the considered paths: in most cases the reflections from the ionospheric F2-layer were changed by the reflections only from the sporadic Es-layer. The parameters of movement of the disturbance front were estimated on the basis of OIS data of the paths. The average velocity of the front movements from east to west was about V = 440 m/s. Even the moderate growth of riometer absorption within the region of radio paths' locations, resulted in loss of multihop modes in the signal reflections from sporadic layers. It also resulted in a sharp decrease of signal strength at the paths. Real distance-frequency characteristics (DFC) of the paths were compared to DFC calculated on the basis of International Reference Ionosphere (IRI) model. It was revealed that on a quiet day of March, 15th, the real and the calculated DFC are similar or coincide in the majority of cases. During the disturbed days of March, 17-19, most commonly observed are the significant differences between the calculated and the experimental data. The most pronounced difference is revealed while estimating the character of OIS signals' reflections from Es-layers.

Analysis of rain fade duration models for Earth-to-satellite path based on data measured in Malaysia

International Nuclear Information System (INIS)

Dao, Hassan; Rafiqul, Islam Md; Al-Khateeb, Khalid A S

2013-01-01

Statistical analysis of rain fade duration is crucial information for system engineer to design and plan a fade mitigation technique (FMT) for the satellite communication system. An investigation is carried out based on data measured of one year period in Kuala Lumpur, Malaysia from satellite path of MEASAT3. This paper presents statistical analysis of measured fade duration on high elevation angle (77.4°) in Ku-band compared to three prediction models of fade duration. It is found that none of the models could predict measured fade duration distribution accurately

Path integral measure for first-order and metric gravities

International Nuclear Information System (INIS)

Aros, Rodrigo; Contreras, Mauricio; Zanelli, Jorge

2003-01-01

The equivalence between the path integrals for first-order gravity and the standard torsion-free, metric gravity in 3 + 1 dimensions is analysed. Starting with the path integral for first-order gravity, the correct measure for the path integral of the metric theory is obtained

Extremal and Degree Conditions for Path Extendability in Digraphs

NARCIS (Netherlands)

Zhang, Zan-Bo; Zhang, Xiaoyan; Broersma, Hajo; Lou, Dingjun

2017-01-01

In the study of cycles and paths, the meta-conjecture of Bondy that sufficient conditions for Hamiltonicity often imply pancyclicity has motivated research on the existence of cycles and paths of many lengths. Hendry further introduced the stronger concepts of cycle extendability and path

Excitation of Structures Near Railway Tracks-Analysis of the Wave Propagation Path

DEFF Research Database (Denmark)

Bucinskas, Paulius; Andersen, Lars Vabbersgaard

2017-01-01

High-speed rails are an attractive alternative to other forms of intercity transportation. It is a fast, cost-efficient and environmentally friendly solution, which is being developed in various countries across the world. However, in order to be successful, high-speed rails need to transport...... trains. Unfortunately, the prediction of vibrations in nearby structures is difficult, as wave propagation from the vibration source to the structure is a complex phenomenon. The behaviour of the structure is highly dependent on the path along which the vibrations travel between their source...

Teleconnection Paths via Climate Network Direct Link Detection.

Science.gov (United States)

Zhou, Dong; Gozolchiani, Avi; Ashkenazy, Yosef; Havlin, Shlomo

2015-12-31

Teleconnections describe remote connections (typically thousands of kilometers) of the climate system. These are of great importance in climate dynamics as they reflect the transportation of energy and climate change on global scales (like the El Niño phenomenon). Yet, the path of influence propagation between such remote regions, and weighting associated with different paths, are only partially known. Here we propose a systematic climate network approach to find and quantify the optimal paths between remotely distant interacting locations. Specifically, we separate the correlations between two grid points into direct and indirect components, where the optimal path is found based on a minimal total cost function of the direct links. We demonstrate our method using near surface air temperature reanalysis data, on identifying cross-latitude teleconnections and their corresponding optimal paths. The proposed method may be used to quantify and improve our understanding regarding the emergence of climate patterns on global scales.

Survey of Robot 3D Path Planning Algorithms

Directory of Open Access Journals (Sweden)

Liang Yang

2016-01-01

Full Text Available Robot 3D (three-dimension path planning targets for finding an optimal and collision-free path in a 3D workspace while taking into account kinematic constraints (including geometric, physical, and temporal constraints. The purpose of path planning, unlike motion planning which must be taken into consideration of dynamics, is to find a kinematically optimal path with the least time as well as model the environment completely. We discuss the fundamentals of these most successful robot 3D path planning algorithms which have been developed in recent years and concentrate on universally applicable algorithms which can be implemented in aerial robots, ground robots, and underwater robots. This paper classifies all the methods into five categories based on their exploring mechanisms and proposes a category, called multifusion based algorithms. For all these algorithms, they are analyzed from a time efficiency and implementable area perspective. Furthermore a comprehensive applicable analysis for each kind of method is presented after considering their merits and weaknesses.

Path entanglement of photons by non-local bunching

International Nuclear Information System (INIS)

Eisenberg, H.; Hodelin, J.; Khoury, G.; Bouwmeester, D.

2005-01-01

Full Text:Path entangled photon states can be used to overcome classical limits on the accuracy of interferometric measurements such as the diffraction limit. These states are superpositions of finding n photons in one out of two (or more) paths. Using stimulated parametric down-conversion, we propose and demonstrate a method for generating heralded multiphoton path entanglement, without applying post-selection. parametric down-conversion is relatively easy to produce compared to pure Fock states as demanded by other proposals. By a special coincidence detection at one down converted arm, the photons of the second arm non-locally bunch into the desired state. Entanglement in photon number is created between two polarization modes rather than two paths. A polarization beam-splitter and a 2 wave plate can translate between the two representations. The experimental generation of a two-photon path entangled state was detected by observing interference at half the photon wavelength. The scheme is generally extendable to higher photon numbers

Tornado intensity estimated from damage path dimensions.

Science.gov (United States)

Elsner, James B; Jagger, Thomas H; Elsner, Ian J

2014-01-01

The Newcastle/Moore and El Reno tornadoes of May 2013 are recent reminders of the destructive power of tornadoes. A direct estimate of a tornado's power is difficult and dangerous to get. An indirect estimate on a categorical scale is available from a post-storm survery of the damage. Wind speed bounds are attached to the scale, but the scale is not adequate for analyzing trends in tornado intensity separate from trends in tornado frequency. Here tornado intensity on a continuum is estimated from damage path length and width, which are measured on continuous scales and correlated to the EF rating. The wind speeds on the EF scale are treated as interval censored data and regressed onto the path dimensions and fatalities. The regression model indicates a 25% increase in expected intensity over a threshold intensity of 29 m s(-1) for a 100 km increase in path length and a 17% increase in expected intensity for a one km increase in path width. The model shows a 43% increase in the expected intensity when fatalities are observed controlling for path dimensions. The estimated wind speeds correlate at a level of .77 (.34, .93) [95% confidence interval] with a small sample of wind speeds estimated independently from a doppler radar calibration. The estimated wind speeds allow analyses to be done on the tornado database that are not possible with the categorical scale. The modeled intensities can be used in climatology and in environmental and engineering applications. Research is needed to understand the upward trends in path length and width.

Tornado intensity estimated from damage path dimensions.

Directory of Open Access Journals (Sweden)

James B Elsner

Full Text Available The Newcastle/Moore and El Reno tornadoes of May 2013 are recent reminders of the destructive power of tornadoes. A direct estimate of a tornado's power is difficult and dangerous to get. An indirect estimate on a categorical scale is available from a post-storm survery of the damage. Wind speed bounds are attached to the scale, but the scale is not adequate for analyzing trends in tornado intensity separate from trends in tornado frequency. Here tornado intensity on a continuum is estimated from damage path length and width, which are measured on continuous scales and correlated to the EF rating. The wind speeds on the EF scale are treated as interval censored data and regressed onto the path dimensions and fatalities. The regression model indicates a 25% increase in expected intensity over a threshold intensity of 29 m s(-1 for a 100 km increase in path length and a 17% increase in expected intensity for a one km increase in path width. The model shows a 43% increase in the expected intensity when fatalities are observed controlling for path dimensions. The estimated wind speeds correlate at a level of .77 (.34, .93 [95% confidence interval] with a small sample of wind speeds estimated independently from a doppler radar calibration. The estimated wind speeds allow analyses to be done on the tornado database that are not possible with the categorical scale. The modeled intensities can be used in climatology and in environmental and engineering applications. Research is needed to understand the upward trends in path length and width.

A fast spectrum dual path flow cermet reactor

International Nuclear Information System (INIS)

Anghaie, S.; Feller, G.J.; Peery, S.D.; Parsley, R.C.

1993-01-01

A cermet fueled, dual path fast reactor for space nuclear propulsion applications is conceptually designed. The reactor utilizes an outer annulus core and an inner cylindrical core with radial and axial reflector. The dual path flow minimizes the impact of power peaking near the radial reflector. Basic neutronics and core design aspects of the reactor are discussed. The dual path reactor is integrated into a 25000 lbf thrust nuclear rocket

Polymer quantum mechanics some examples using path integrals

International Nuclear Information System (INIS)

Parra, Lorena; Vergara, J. David

2014-01-01

In this work we analyze several physical systems in the context of polymer quantum mechanics using path integrals. First we introduce the group averaging method to quantize constrained systems with path integrals and later we use this procedure to compute the effective actions for the polymer non-relativistic particle and the polymer harmonic oscillator. We analyze the measure of the path integral and we describe the semiclassical dynamics of the systems

Effects of Glide Path on the Centering Ability and Preparation Time of Two Reciprocating Instruments

Science.gov (United States)

Coelho, Marcelo Santos; Fontana, Carlos Eduardo; Kato, Augusto Shoji; de Martin, Alexandre Sigrist; da Silveira Bueno, Carlos Eduardo

2016-01-01

Introduction: The aim of this in vitro study was to evaluate the effects of establishing glide path on the centering ability and preparation time of two single-file reciprocating systems in mesial root canals of mandibular molars. Methods and Materials: Sixty extracted mandibular molars with curvatures of 25-39 degrees and separate foramina for the mesiobuccal and mesiolingual canals, were divided into four groups (n=15); WaveOne+glide path; WaveOne; Reciproc+glide path and Reciproc. Non-patent canals were excluded and only one canal in each tooth was instrumented. A manual glide path was established in first and third groups with #10, 15 and 20 hand K-files. Preparation was performed with reciprocating in-and-out motion, with a 3-4 mm amplitude and slight apical pressure. Initial and final radiographs were taken to analyze the amount of dentin removed in the instrumented canals. The radiographs were superimposed with an image editing software and examined to assess discrepancies at 3-, 6- and 9-mm distances from the apex. The Kruskal-Wallis test was used for statistical analysis. The level of significance was set at 0.05. Results: Preparation in groups without glide paths was swifter than the other groups (P=0.001). However, no difference was observed regarding centering ability. Conclusion: Establishing a glide path increased the total instrumentation time for preparing curved canals with WaveOne and Reciproc instruments. Glide path had no influence on the centering ability of these systems. PMID:26843875

Using meta-analytic path analysis to test theoretical predictions in health behavior: An illustration based on meta-analyses of the theory of planned behavior

OpenAIRE

Hagger, Martin; Chan, Dervin K. C.; Protogerou, Cleo; Chatzisarantis, Nikos L. D.

2016-01-01

Objective Synthesizing research on social cognitive theories applied to health behavior is an important step in the development of an evidence base of psychological factors as targets for effective behavioral interventions. However, few meta-analyses of research on social cognitive theories in health contexts have conducted simultaneous tests of theoretically-stipulated pattern effects using path analysis. We argue that conducting path analyses of meta-analytic effects among constructs fr...

From path integrals to anyons

International Nuclear Information System (INIS)

Canright, G.S.

1992-01-01

I offer a pedagogical review of the homotopy arguments for fractional statistics in two dimensions. These arguments arise naturally in path-integral language since they necessarily consider the properties of paths rather than simply permutations. The braid group replaces the permutation group as the basic structure for quantum statistics; hence properties of the braid group on several surfaces are briefly discussed. Finally, the question of multiple (real-space) occupancy is addressed; I suggest that the ''traditional'' treatment of this question (ie, an assumption that many-anyon wavefunctions necessarily vanish for multiple occupancy) needs reexamination

Multiagent path-finding in strategic games

OpenAIRE

Mihevc, Simon

2014-01-01

In this thesis I worked on creating, comparing and improving algorithms for multi-agent path planning on a domain typical for real-time strategy games. I implemented and compared Multiagent pathfinding using clearance and Multiagent pathfinding using independence detection and operator decomposition. I discovered that they had problems maintaining group compactness and took too long to calculate the path. I considerably improved the efficiency of both algorithms.

Long open-path measurements of greenhouse gases in air using near-infrared Fourier transform spectroscopy

Directory of Open Access Journals (Sweden)

D. W. T. Griffith

2018-03-01

Full Text Available In complex and urban environments, atmospheric trace gas composition is highly variable in time and space. Point measurement techniques for trace gases with in situ instruments are well established and accurate, but do not provide spatial averaging to compare against developing high-resolution atmospheric models of composition and meteorology with resolutions of the order of a kilometre. Open-path measurement techniques provide path average concentrations and spatial averaging which, if sufficiently accurate, may be better suited to assessment and interpretation with such models. Open-path Fourier transform spectroscopy (FTS in the mid-infrared region, and differential optical absorption spectroscopy (DOAS in the UV and visible, have been used for many years for open-path spectroscopic measurements of selected species in both clean air and in polluted environments. Near infrared instrumentation allows measurements over longer paths than mid-infrared FTS for species such as greenhouse gases which are not easily accessible to DOAS.In this pilot study we present the first open-path near-infrared (4000–10 000 cm−1, 1.0–2.5 µm FTS measurements of CO2, CH4, O2, H2O and HDO over a 1.5 km path in urban Heidelberg, Germany. We describe the construction of the open-path FTS system, the analysis of the collected spectra, several measures of precision and accuracy of the measurements, and the results a four-month trial measurement period in July–November 2014. The open-path measurements are compared to calibrated in situ measurements made at one end of the open path. We observe significant differences of the order of a few ppm for CO2 and a few tens of ppb for CH4 between the open-path and point measurements which are 2 to 4 times the measurement repeatability, but we cannot unequivocally assign the differences to specific local sources or sinks. We conclude that open-path FTS may provide a valuable new tool for investigations of

Multi-rate path-following control for unmanned air vehicles

NARCIS (Netherlands)

Guerreiro Tome Antunes, D.J.; Silvestre, C.J.; Cunha, R.

2008-01-01

A methodology is provided to tackle the path-following integrated guidance and control problem for unmanned air vehicles with measured outputs available at different rates. The path-following problem is addressed by defining a suitable non-linear path dependent error space to express the vehicle’s

Space-efficient path-reporting approximate distance oracles

DEFF Research Database (Denmark)

Elkin, Michael; Neiman, Ofer; Wulff-Nilsen, Christian

2016-01-01

We consider approximate path-reporting distance oracles, distance labeling and labeled routing with extremely low space requirements, for general undirected graphs. For distance oracles, we show how to break the nlog⁡n space bound of Thorup and Zwick if approximate paths rather than distances need...

Integrated robust controller for vehicle path following

Energy Technology Data Exchange (ETDEWEB)

Mashadi, Behrooz; Ahmadizadeh, Pouyan, E-mail: p-ahmadizadeh@iust.ac.ir; Majidi, Majid, E-mail: m-majidi@iust.ac.ir [Iran University of Science and Technology, School of Automotive Engineering (Iran, Islamic Republic of); Mahmoodi-Kaleybar, Mehdi, E-mail: m-mahmoodi-k@iust.ac.ir [Iran University of Science and Technology, School of Mechanical Engineering (Iran, Islamic Republic of)

2015-02-15

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties.

Integrated robust controller for vehicle path following

International Nuclear Information System (INIS)

Mashadi, Behrooz; Ahmadizadeh, Pouyan; Majidi, Majid; Mahmoodi-Kaleybar, Mehdi

2015-01-01

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties

Path integral representations on the complex sphere

Energy Technology Data Exchange (ETDEWEB)

Grosche, C. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

2007-08-15

In this paper we discuss the path integral representations for the coordinate systems on the complex sphere S{sub 3C}. The Schroedinger equation, respectively the path integral, separates in exactly 21 orthogonal coordinate systems. We enumerate these coordinate systems and we are able to present the path integral representations explicitly in the majority of the cases. In each solution the expansion into the wave-functions is stated. Also, the kernel and the corresponding Green function can be stated in closed form in terms of the invariant distance on the sphere, respectively on the hyperboloid. (orig.)

Experiments with the auction algorithm for the shortest path problem

DEFF Research Database (Denmark)

Larsen, Jesper; Pedersen, Ib

1999-01-01

The auction approach for the shortest path problem (SPP) as introduced by Bertsekas is tested experimentally. Parallel algorithms using the auction approach are developed and tested. Both the sequential and parallel auction algorithms perform significantly worse than a state-of-the-art Dijkstra-l......-like reference algorithm. Experiments are run on a distributed-memory MIMD class Meiko parallel computer....

Path optimization method for the sign problem

Directory of Open Access Journals (Sweden)

Ohnishi Akira

2018-01-01

Full Text Available We propose a path optimization method (POM to evade the sign problem in the Monte-Carlo calculations for complex actions. Among many approaches to the sign problem, the Lefschetz-thimble path-integral method and the complex Langevin method are promising and extensively discussed. In these methods, real field variables are complexified and the integration manifold is determined by the flow equations or stochastically sampled. When we have singular points of the action or multiple critical points near the original integral surface, however, we have a risk to encounter the residual and global sign problems or the singular drift term problem. One of the ways to avoid the singular points is to optimize the integration path which is designed not to hit the singular points of the Boltzmann weight. By specifying the one-dimensional integration-path as z = t +if(t(f ϵ R and by optimizing f(t to enhance the average phase factor, we demonstrate that we can avoid the sign problem in a one-variable toy model for which the complex Langevin method is found to fail. In this proceedings, we propose POM and discuss how we can avoid the sign problem in a toy model. We also discuss the possibility to utilize the neural network to optimize the path.

Minimum dose method for walking-path planning of nuclear facilities

International Nuclear Information System (INIS)

Liu, Yong-kuo; Li, Meng-kun; Xie, Chun-li; Peng, Min-jun; Wang, Shuang-yu; Chao, Nan; Liu, Zhong-kun

2015-01-01

Highlights: • For radiation environment, the environment model is proposed. • For the least dose walking path problem, a path-planning method is designed. • The path-planning virtual–real mixed simulation program is developed. • The program can plan walking path and simulate. - Abstract: A minimum dose method based on staff walking road network model was proposed for the walking-path planning in nuclear facilities. A virtual–reality simulation program was developed using C# programming language and Direct X engine. The simulation program was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method was effective in providing safety for people walking in nuclear facilities

Effect of temporal organization of the visuo-locomotor coupling on the predictive steering

Directory of Open Access Journals (Sweden)

Yves Philippe Rybarczyk

2012-07-01

Full Text Available Studies on the direction of a driver’s gaze while taking a bend show that the individual looks towards the tangent-point of the inside curve. Mathematically, the direction of this point in relation to the car enables the driver to predict the curvature of the road. In the same way, when a person walking in the street makes a turn at the corner, his/her gaze anticipates the rotation of the body. A current explanation for the visuo-motor anticipation over the locomotion would be that the brain, involved in a steering behaviour, executes an internal model of the trajectory that anticipates the path completion, and not the contrary. This paper proposes to test this hypothesis by studying the effect of an artificial manipulation of the visuo-locomotor coupling on the trajectory prediction. In this experiment, subjects remotely control a mobile robot with a pan-tilt camera. This experimental paradigm is chosen to easily and precisely manipulate the temporal organization of the visuo-locomotor coupling. Results show that only the visuo-locomotor coupling organized from the visual sensor to the locomotor organs enables i a significant smoothness of the trajectory and ii a velocity-curvature relationship that follows the 2/3 Power Law. These findings are consistent with the theory of an anticipatory construction of an internal model of the trajectory. This mental representation used by the brain as a forward prediction of the path formation seems conditioned by the motor program. The overall results are discussed in terms of the sensorimotor scheme bases of the predictive coding.

Emotion dysregulation and peer drinking norms uniquely predict alcohol-related problems via motives.

Science.gov (United States)

Simons, Raluca M; Hahn, Austin M; Simons, Jeffrey S; Murase, Hanako

2017-08-01

This study examined the relationships between emotion dysregulation, peer drinking norms, drinking motives, and alcohol-related outcomes among 435 college students. We examined the mediating roles of drinking motives when predicting alcohol consumption and related problems from the subscales of the Difficulties in Emotion Regulation Scale (DERS; Gratz and Roemer, 2004) via negative and positive reinforcement models. First, we hypothesized that individuals who lack in emotion regulation strategies or have difficulties in accepting negative emotions are more likely to drink to cope. Additionally, we hypothesized that individuals who act impulsively or become distracted when upset as well as those with higher peer drinking norms are more likely to drink for social and enhancement motives. The results of the path model indicated that limited access to emotion regulation strategies significantly predicted alcohol-related problems via both depression and anxiety coping motives, but did not predict alcohol consumption. Nonacceptance of emotional responses was not significantly associated with coping motives. Impulsivity had a significant direct relationship with alcohol problems. Difficulty in engaging in goal-directed behaviors predicted both enhancement and social motives, but only enhancement motives in turn predicted consumption. Norms indirectly predicted problems via enhancement motives and consumption. The results indicated that using alcohol to reduce negative or to increase positive emotions increases alcohol consumption and alcohol-related problems. Overall, results advance our understanding of the mechanisms of increased alcohol use and problems among college students. Copyright © 2017 Elsevier B.V. All rights reserved.

A Path Space Extension for Robust Light Transport Simulation

DEFF Research Database (Denmark)

Hachisuka, Toshiya; Pantaleoni, Jacopo; Jensen, Henrik Wann

2012-01-01

We present a new sampling space for light transport paths that makes it possible to describe Monte Carlo path integration and photon density estimation in the same framework. A key contribution of our paper is the introduction of vertex perturbations, which extends the space of paths with loosely...

Variational nature, integration, and properties of Newton reaction path.

Science.gov (United States)

Bofill, Josep Maria; Quapp, Wolfgang

2011-02-21

The distinguished coordinate path and the reduced gradient following path or its equivalent formulation, the Newton trajectory, are analyzed and unified using the theory of calculus of variations. It is shown that their minimum character is related to the fact that the curve is located in a valley region. In this case, we say that the Newton trajectory is a reaction path with the category of minimum energy path. In addition to these findings a Runge-Kutta-Fehlberg algorithm to integrate these curves is also proposed.

Variational nature, integration, and properties of Newton reaction path

Science.gov (United States)

Bofill, Josep Maria; Quapp, Wolfgang

2011-02-01

The distinguished coordinate path and the reduced gradient following path or its equivalent formulation, the Newton trajectory, are analyzed and unified using the theory of calculus of variations. It is shown that their minimum character is related to the fact that the curve is located in a valley region. In this case, we say that the Newton trajectory is a reaction path with the category of minimum energy path. In addition to these findings a Runge-Kutta-Fehlberg algorithm to integrate these curves is also proposed.

Quantum mechanics on the half-line using path integrals

International Nuclear Information System (INIS)

Clark, T.E.; Menikoff, R.; Sharp, D.H.

1980-01-01

We study the Feynman path-integral formalism for the constrained problem of a free particle moving on the half-line. It is shown that the effect of the boundary condition at the origin can be incorporated into the path integral by a simple modification of the action. The small-time behavior of the Green's function can be obtained from the stationary-phase evaluation of our expression for the path integral, which in this case includes contributions from both the direct and reflected classical paths

Automated path length and M56 measurements at Jefferson Lab

International Nuclear Information System (INIS)

Hardy, D.; Tang, J.; Legg, R.

1997-01-01

Accurate measurement of path length and path length changes versus momentum (M 56 ) are critical for maintaining minimum beam energy spread in the CEBAF (Continuous Electron Beam Accelerator Facility) accelerator at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The relative path length for each circuit of the beam (1256m) must be equal within 1.5 degrees of 1497 MHz RF phase. A relative path length measurement is made by measuring the relative phases of RF signals from a cavity that is separately excited for each pass of a 4.2 μs pulsed beam. This method distinguishes the path length to less than 0.5 path length error. The development of a VME based automated measurement system for path length and M 56 has contributed to faster machine setup time and has the potential for use as a feedback parameter for automated control

Hot gas path component having near wall cooling features

Science.gov (United States)

Miranda, Carlos Miguel; Kottilingam, Srikanth Chandrudu; Lacy, Benjamin Paul

2017-11-28

A method for providing micro-channels in a hot gas path component includes forming a first micro-channel in an exterior surface of a substrate of the hot gas path component. A second micro-channel is formed in the exterior surface of the hot gas path component such that it is separated from the first micro-channel by a surface gap having a first width. The method also includes disposing a braze sheet onto the exterior surface of the hot gas path component such that the braze sheet covers at least of portion of the first and second micro-channels, and heating the braze sheet to bond it to at least a portion of the exterior surface of the hot gas path component.

Significance of High Resolution GHRSST on prediction of Indian Summer Monsoon

KAUST Repository

Jangid, Buddhi Prakash

2017-02-24

In this study, the Weather Research and Forecasting (WRF) model was used to assess the importance of very high resolution sea surface temperature (SST) on seasonal rainfall prediction. Two different SST datasets available from the National Centers for Environmental Prediction (NCEP) global model analysis and merged satellite product from Group for High Resolution SST (GHRSST) are used as a lower boundary condition in the WRF model for the Indian Summer Monsoon (ISM) 2010. Before using NCEP SST and GHRSST for model simulation, an initial verification of NCEP SST and GHRSST are performed with buoy measurements. It is found that approximately 0.4 K root mean square difference (RMSD) in GHRSST and NCEP SST when compared with buoy observations available over the Indian Ocean during 01 May to 30 September 2010. Our analyses suggest that use of GHRSST as lower boundary conditions in the WRF model improve the low level temperature, moisture, wind speed and rainfall prediction over ISM region. Moreover, temporal evolution of surface parameters such as temperature, moisture and wind speed forecasts associated with monsoon is also improved with GHRSST forcing as a lower boundary condition. Interestingly, rainfall prediction is improved with the use of GHRSST over the Western Ghats, which mostly not simulated in the NCEP SST based experiment.

Significance of High Resolution GHRSST on prediction of Indian Summer Monsoon

KAUST Repository

Jangid, Buddhi Prakash; Kumar, Prashant; Attada, Raju; Kumar, Raj

2017-01-01

In this study, the Weather Research and Forecasting (WRF) model was used to assess the importance of very high resolution sea surface temperature (SST) on seasonal rainfall prediction. Two different SST datasets available from the National Centers for Environmental Prediction (NCEP) global model analysis and merged satellite product from Group for High Resolution SST (GHRSST) are used as a lower boundary condition in the WRF model for the Indian Summer Monsoon (ISM) 2010. Before using NCEP SST and GHRSST for model simulation, an initial verification of NCEP SST and GHRSST are performed with buoy measurements. It is found that approximately 0.4 K root mean square difference (RMSD) in GHRSST and NCEP SST when compared with buoy observations available over the Indian Ocean during 01 May to 30 September 2010. Our analyses suggest that use of GHRSST as lower boundary conditions in the WRF model improve the low level temperature, moisture, wind speed and rainfall prediction over ISM region. Moreover, temporal evolution of surface parameters such as temperature, moisture and wind speed forecasts associated with monsoon is also improved with GHRSST forcing as a lower boundary condition. Interestingly, rainfall prediction is improved with the use of GHRSST over the Western Ghats, which mostly not simulated in the NCEP SST based experiment.

Generalized measures and the Feynman path integral

International Nuclear Information System (INIS)

Maslov, V.P.; Chebotarev, A.M.

1976-01-01

Generalizations are obtained for the earlier results by the authors concerning the inclusion of the Feynmann path integral in the momentum representation into the general integration theory. Feynmann path integrals are considered which do not represent T-products. Generalized Feynmann measure in the configuration representation is introduced

Approximate shortest homotopic paths in weighted regions

KAUST Repository

Cheng, Siuwing; Jin, Jiongxin; Vigneron, Antoine E.; Wang, Yajun

2012-01-01

A path P between two points s and t in a polygonal subdivision T with obstacles and weighted regions defines a class of paths that can be deformed to P without passing over any obstacle. We present the first algorithm that, given P and a relative

Nonadiabatic transition path sampling

International Nuclear Information System (INIS)

Sherman, M. C.; Corcelli, S. A.

2016-01-01

Fewest-switches surface hopping (FSSH) is combined with transition path sampling (TPS) to produce a new method called nonadiabatic path sampling (NAPS). The NAPS method is validated on a model electron transfer system coupled to a Langevin bath. Numerically exact rate constants are computed using the reactive flux (RF) method over a broad range of solvent frictions that span from the energy diffusion (low friction) regime to the spatial diffusion (high friction) regime. The NAPS method is shown to quantitatively reproduce the RF benchmark rate constants over the full range of solvent friction. Integrating FSSH within the TPS framework expands the applicability of both approaches and creates a new method that will be helpful in determining detailed mechanisms for nonadiabatic reactions in the condensed-phase.

Line-of-Sight Path Following for Dubins Paths with Adaptive Sideslip Compensation of Drift Forces

DEFF Research Database (Denmark)

Fossen, Thor Inge; Pettersen, Kristin Ytterstad; Galeazzi, Roberto

2015-01-01

guidance law is intended for maneuvering in the horizontal-plane at given speeds and typical applications are marine craft, autonomous underwater vehicles (AUVs), unmanned aerial vehicles (UAVs) as well as other vehicles and craft where the goal is to follow a predefined parametrized curve without time......-sight (LOS) guidance principle used by ancient navigators, which is here extended to path following of Dubins paths. The unknown sideslip angle is treated as a constant parameter, which is estimated using an adaptation law. The equilibrium points of the cross-track and parameter estimation errors are proven...

Path Integrals in Quantum Mechanics

International Nuclear Information System (INIS)

Chetouani, L

2005-01-01

By treating path integrals the author, in this book, places at the disposal of the reader a modern tool for the comprehension of standard quantum mechanics. Thus the most important applications, such as the tunnel effect, the diffusion matrix, etc, are presented from an original point of view on the action S of classical mechanics while having it play a central role in quantum mechanics. What also emerges is that the path integral describes these applications more richly than are described traditionally by differential equations, and consequently explains them more fully. The book is certainly of high quality in all aspects: original in presentation, rigorous in the demonstrations, judicious in the choice of exercises and, finally, modern, for example in the treatment of the tunnel effect by the method of instantons. Moreover, the correspondence that exists between classical and quantum mechanics is well underlined. I thus highly recommend this book (the French version being already available) to those who wish to familiarize themselves with formulation by path integrals. They will find, in addition, interesting topics suitable for exploring further. (book review)

Distribution definition of path integrals

International Nuclear Information System (INIS)

Kerler, W.

1979-01-01

By starting from quantum mechanics it turns out that a rather general definition of quantum functional integrals can be given which is based on distribution theory. It applies also to curved space and provides clear rules for non-linear transformations. The refinements necessary in usual definitions of path integrals are pointed out. Since the quantum nature requires special care with time sequences, it is not the classical phase space which occurs in the phase-space form of the path integral. Feynman's configuration-space form only applies to a highly specialized situation, and therefore is not a very advantageous starting point for general investigations. It is shown that the commonly used substitutions of variables do not properly account for quantum effects. The relation to the traditional ordering problem is clarified. The distribution formulation has allowed to treat constrained systems directly at the quantum level, to complete the path integral formulation of the equivalence theorem, and to define functional integrals also for space translation after the transition to fields. (orig.)

Environmental influences on fruit and vegetable intake: Results from a path analytic model

Science.gov (United States)

Liese, Angela D.; Bell, Bethany A.; Barnes, Timothy L.; Colabianchi, Natalie; Hibbert, James D.; Blake, Christine E.; Freedman, Darcy A.

2014-01-01

Objective Fruit and vegetable intake (F&V) is influenced by behavioral and environmental factors, but these have rarely been assessed simultaneously. We aimed to quantify the relative influence of supermarket availability, perceptions of the food environment, and shopping behavior on F&V intake. Design A cross-sectional study. Setting Eight-counties in South Carolina, USA, with verified locations of all supermarkets. Subjects A telephone survey of 831 household food shoppers ascertained F&V intake with a 17-item screener, primary food store location, shopping frequency, perceptions of healthy food availability, and calculated GIS-based supermarket availability. Path analysis was conducted. We report standardized beta coefficients on paths significant at the 0.05 level. Results Frequency of grocery shopping at primary food store (β=0.11) was the only factor exerting an independent, statistically significant direct effect on F&V intake. Supermarket availability was significantly associated with distance to food store (β=-0.24) and shopping frequency (β=0.10). Increased supermarket availability was significantly and positively related to perceived healthy food availability in the neighborhood (β=0.18) and ease of shopping access (β=0.09). Collectively considering all model paths linked to perceived availability of healthy foods, this measure was the only other factor to have a significant total effect on F&V intake. Conclusions While the majority of literature to date has suggested an independent and important role of supermarket availability for F&V intake, our study found only indirect effects of supermarket availability and suggests that food shopping frequency and perceptions of healthy food availability are two integral components of a network of influences on F&V intake. PMID:24192274

Path-integral Monte Carlo study of phonons in the bcc phase of Helium-3

OpenAIRE

Sorkin, V.; Polturak, E.; Adler, Joan

2006-01-01

Using Path Integral Monte Carlo and the Maximum Entropy method, we calculate the dynamic structure factor of solid He-3 in the bcc phase at a finite temperature of T = 1.6 K and a molar volume of 21.5 cm^3. From the single phonon dynamic structure factor, we obtain both the longitudinal and transverse phonon branches along the main crystalline directions, [001], [011] and [111]. Our results are compared with other theoretical predictions and available experimental data.

Analysis of Crack Propagation Path on the Anisotropic Bi-Material Rock

Directory of Open Access Journals (Sweden)

Chao-Shi Chen

2010-01-01

Full Text Available This paper presents a single-domain boundary element method (SDBEM for linear elastic fracture mechanics analysis in the 2D anisotropic bimaterial. In this formulation, the displacement integral equation is collocated on the uncracked boundary only, and the traction integral equation is collocated on one side of the crack surface only. The complete fundamental solution (Green's function for anisotropic bi-materials was also derived and implemented into the boundary integral formulation so the discretization along the interface can be avoided except for the interfacial crack part. A special crack-tip element was introduced to capture exactly the crack-tip behavior. A computer program with the FORTRAN code has been developed to effectively calculate the stress intensity factors, crack initiation angle, and propagation path of an anisotropic bi-material. This SDBEM program has been verified having a good accuracy with the previous researches. In addition, a rock of type (1/(2 disk specimen with a central crack was made to conduct the Brazilian test under diametrical loading. The result shows that the numerical analysis can predict relatively well the direction of crack initiation and the path of crack propagation.

NemaPath: online exploration of KEGG-based metabolic pathways for nematodes

Directory of Open Access Journals (Sweden)

Wang Zhengyuan

2008-11-01

Full Text Available Abstract Background Nematode.net http://www.nematode.net is a web-accessible resource for investigating gene sequences from parasitic and free-living nematode genomes. Beyond the well-characterized model nematode C. elegans, over 500,000 expressed sequence tags (ESTs and nearly 600,000 genome survey sequences (GSSs have been generated from 36 nematode species as part of the Parasitic Nematode Genomics Program undertaken by the Genome Center at Washington University School of Medicine. However, these sequencing data are not present in most publicly available protein databases, which only include sequences in Swiss-Prot. Swiss-Prot, in turn, relies on GenBank/Embl/DDJP for predicted proteins from complete genomes or full-length proteins. Description Here we present the NemaPath pathway server, a web-based pathway-level visualization tool for navigating putative metabolic pathways for over 30 nematode species, including 27 parasites. The NemaPath approach consists of two parts: 1 a backend tool to align and evaluate nematode genomic sequences (curated EST contigs against the annotated Kyoto Encyclopedia of Genes and Genomes (KEGG protein database; 2 a web viewing application that displays annotated KEGG pathway maps based on desired confidence levels of primary sequence similarity as defined by a user. NemaPath also provides cross-referenced access to nematode genome information provided by other tools available on Nematode.net, including: detailed NemaGene EST cluster information; putative translations; GBrowse EST cluster views; links from nematode data to external databases for corresponding synonymous C. elegans counterparts, subject matches in KEGG's gene database, and also KEGG Ontology (KO identification. Conclusion The NemaPath server hosts metabolic pathway mappings for 30 nematode species and is available on the World Wide Web at http://nematode.net/cgi-bin/keggview.cgi. The nematode source sequences used for the metabolic pathway

Technology Paths in Energy-Efficient and Sustainable Construction

DEFF Research Database (Denmark)

Holm, Jesper; Lund Sørensen, Runa Cecilie

2015-01-01

Various tehcnology paths and regimes, Building codes and standards in energy, eco and sustainable housing......Various tehcnology paths and regimes, Building codes and standards in energy, eco and sustainable housing...

Approximate Shortest Homotopic Paths in Weighted Regions

KAUST Repository

Cheng, Siu-Wing; Jin, Jiongxin; Vigneron, Antoine; Wang, Yajun

2010-01-01

Let P be a path between two points s and t in a polygonal subdivision T with obstacles and weighted regions. Given a relative error tolerance ε ∈(0,1), we present the first algorithm to compute a path between s and t that can be deformed to P

Two Generations of Path Dependence in Economics?

DEFF Research Database (Denmark)

Madsen, Mogens Ove

2010-01-01

Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences – primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

from synchronic variation to a grammaticalization path

African Journals Online (AJOL)

Kate H

Abstract. The authors argue that the synchronic variation of cognate objects of weather verbs exhibited in six African languages of South Africa (Sepedi, Sesotho, Tshivenda, isiXhosa, Xitsonga, and. isiZulu) has a diachronic explanation, and may be represented as a grammaticalization path. This path gradually leads from ...

Target Centroid Position Estimation of Phase-Path Volume Kalman Filtering

Directory of Open Access Journals (Sweden)

Fengjun Hu

2016-01-01

Full Text Available For the problem of easily losing track target when obstacles appear in intelligent robot target tracking, this paper proposes a target tracking algorithm integrating reduced dimension optimal Kalman filtering algorithm based on phase-path volume integral with Camshift algorithm. After analyzing the defects of Camshift algorithm, compare the performance with the SIFT algorithm and Mean Shift algorithm, and Kalman filtering algorithm is used for fusion optimization aiming at the defects. Then aiming at the increasing amount of calculation in integrated algorithm, reduce dimension with the phase-path volume integral instead of the Gaussian integral in Kalman algorithm and reduce the number of sampling points in the filtering process without influencing the operational precision of the original algorithm. Finally set the target centroid position from the Camshift algorithm iteration as the observation value of the improved Kalman filtering algorithm to fix predictive value; thus to make optimal estimation of target centroid position and keep the target tracking so that the robot can understand the environmental scene and react in time correctly according to the changes. The experiments show that the improved algorithm proposed in this paper shows good performance in target tracking with obstructions and reduces the computational complexity of the algorithm through the dimension reduction.

Reactive Path Planning Approach for Docking Robots in Unknown Environment

Directory of Open Access Journals (Sweden)

Peng Cui

2017-01-01

Full Text Available Autonomous robots need to be recharged and exchange information with the host through docking in the long-distance tasks. Therefore, feasible path is required in the docking process to guide the robot and adjust its pose. However, when there are unknown obstacles in the work area, it becomes difficult to determine the feasible path for docking. This paper presents a reactive path planning approach named Dubins-APF (DAPF to solve the path planning problem for docking in unknown environment with obstacles. In this proposed approach the Dubins curves are combined with the designed obstacle avoidance potential field to plan the feasible path. Firstly, an initial path is planned and followed according to the configurations of the robot and the docking station. Then when the followed path is evaluated to be infeasible, the intermediate configuration is calculated as well as the replanned path based on the obstacle avoidance potential field. The robot will be navigated to the docking station with proper pose eventually via the DAPF approach. The proposed DAPF approach is efficient and does not require the prior knowledge about the environment. Simulation results are given to validate the effectiveness and feasibility of the proposed approach.

A Dynamic Hidden Forwarding Path Planning Method Based on Improved Q-Learning in SDN Environments

Directory of Open Access Journals (Sweden)

Yun Chen

2018-01-01

Full Text Available Currently, many methods are available to improve the target network’s security. The vast majority of them cannot obtain an optimal attack path and interdict it dynamically and conveniently. Almost all defense strategies aim to repair known vulnerabilities or limit services in target network to improve security of network. These methods cannot response to the attacks in real-time because sometimes they need to wait for manufacturers releasing corresponding countermeasures to repair vulnerabilities. In this paper, we propose an improved Q-learning algorithm to plan an optimal attack path directly and automatically. Based on this path, we use software-defined network (SDN to adjust routing paths and create hidden forwarding paths dynamically to filter vicious attack requests. Compared to other machine learning algorithms, Q-learning only needs to input the target state to its agents, which can avoid early complex training process. We improve Q-learning algorithm in two aspects. First, a reward function based on the weights of hosts and attack success rates of vulnerabilities is proposed, which can adapt to different network topologies precisely. Second, we remove the actions and merge them into every state that reduces complexity from O(N3 to O(N2. In experiments, after deploying hidden forwarding paths, the security of target network is boosted significantly without having to repair network vulnerabilities immediately.

Some instructive examples of Mayer's interference in path integral

International Nuclear Information System (INIS)

Fiziev, P.P.

1984-01-01

A new technique of path integral evaluation by a discretization procedure is proposed. It is based on the requirement, found previously, to single out the set of classical trajectories over which the summation is performed. The notion of Mayer's interference is introduced and illustrated by a number of simple examples. The choice of the set of paths is shown to induce a corresponding quantization procedure and this line is followed to demonstrate its connection with the symmetries of the problem. The possibility of extracting information on the space of quantum states from path integrals has been reviewed. A class of paths has been found; the summation over these paths within the framework of the suggested approach produces the well known results for the motion in a homogeneous field and for the harmonic oscillator

Quad-rotor flight path energy optimization

Science.gov (United States)

Kemper, Edward

Quad-Rotor unmanned areal vehicles (UAVs) have been a popular area of research and development in the last decade, especially with the advent of affordable microcontrollers like the MSP 430 and the Raspberry Pi. Path-Energy Optimization is an area that is well developed for linear systems. In this thesis, this idea of path-energy optimization is extended to the nonlinear model of the Quad-rotor UAV. The classical optimization technique is adapted to the nonlinear model that is derived for the problem at hand, coming up with a set of partial differential equations and boundary value conditions to solve these equations. Then, different techniques to implement energy optimization algorithms are tested using simulations in Python. First, a purely nonlinear approach is used. This method is shown to be computationally intensive, with no practical solution available in a reasonable amount of time. Second, heuristic techniques to minimize the energy of the flight path are tested, using Ziegler-Nichols' proportional integral derivative (PID) controller tuning technique. Finally, a brute force look-up table based PID controller is used. Simulation results of the heuristic method show that both reliable control of the system and path-energy optimization are achieved in a reasonable amount of time.

Directed paths in a layered environment

International Nuclear Information System (INIS)

Alvarez, J; Janse van Rensburg, E J

2008-01-01

A polymer in a layered environment is modeled as a directed path in a layered square lattice composed of alternating A-layers of width w a and B-layers of width w b . In this paper we consider general cases of this model, where edges in the path interact with the layers, and vertices in the path interact with interfaces between adjacent layers. The phase diagram exhibits different regimes. In particular, we found that the path may be localized to one layer, be adsorbed on an interface between two layers or be delocalized across layers. We examine special aspects of the model in detail: the asymptotic regimes of the models are examined, and entropic forces on the interfaces are determined. We focus on several different cases, including models with layers of equal or similar width. More general models of layers with different but finite widths, or with one layer of infinite width, are also examined in detail. Several of these models exhibit phase behavior which relate to well-studied polymer phase behavior such as adsorption at an impenetrable wall, pinning at an interface between two immiscible solvents, steric stabilization of colloidal particles and sensitized flocculation of colloidal particles by polymers

New framework for the Feynman path integral

International Nuclear Information System (INIS)

Shaharir, M.Z.

1986-01-01

The well-known Fourier integral solution of the free diffusion equation in an arbitrary Euclidean space is reduced to Feynmannian integrals using the method partly contained in the formulation of the Fresnelian integral. By replacing the standard Hilbert space underlying the present mathematical formulation of the Feynman path integral by a new Hilbert space, the space of classical paths on the tangent bundle to the Euclidean space (and more general to an arbitrary Riemannian manifold) equipped with a natural inner product, we show that our Feynmannian integral is in better agreement with the qualitative features of the original Feynman path integral than the previous formulations of the integral

Path space measures for Dirac and Schroedinger equations: Nonstandard analytical approach

International Nuclear Information System (INIS)

Nakamura, T.

1997-01-01

A nonstandard path space *-measure is constructed to justify the path integral formula for the Dirac equation in two-dimensional space endash time. A standard measure as well as a standard path integral is obtained from it. We also show that, even for the Schroedinger equation, for which there is no standard measure appropriate for a path integral, there exists a nonstandard measure to define a *-path integral whose standard part agrees with the ordinary path integral as defined by a limit from time-slice approximant. copyright 1997 American Institute of Physics

Predicting Intentions of a Familiar Significant Other Beyond the Mirror Neuron System

Directory of Open Access Journals (Sweden)

Stephanie Cacioppo

2017-08-01

Full Text Available Inferring intentions of others is one of the most intriguing issues in interpersonal interaction. Theories of embodied cognition and simulation suggest that this mechanism takes place through a direct and automatic matching process that occurs between an observed action and past actions. This process occurs via the reactivation of past self-related sensorimotor experiences within the inferior frontoparietal network (including the mirror neuron system, MNS. The working model is that the anticipatory representations of others' behaviors require internal predictive models of actions formed from pre-established, shared representations between the observer and the actor. This model suggests that observers should be better at predicting intentions performed by a familiar actor, rather than a stranger. However, little is known about the modulations of the intention brain network as a function of the familiarity between the observer and the actor. Here, we combined functional magnetic resonance imaging (fMRI with a behavioral intention inference task, in which participants were asked to predict intentions from three types of actors: A familiar actor (their significant other, themselves (another familiar actor, and a non-familiar actor (a stranger. Our results showed that the participants were better at inferring intentions performed by familiar actors than non-familiar actors and that this better performance was associated with greater activation within and beyond the inferior frontoparietal network i.e., in brain areas related to familiarity (e.g., precuneus. In addition, and in line with Hebbian principles of neural modulations, the more the participants reported being cognitively close to their partner, the less the brain areas associated with action self-other comparison (e.g., inferior parietal lobule, attention (e.g., superior parietal lobule, recollection (hippocampus, and pair bond (ventral tegmental area, VTA were recruited, suggesting that the

Reaction path simulations in multicomponent materials

International Nuclear Information System (INIS)

Seifert, H.J.

1999-01-01

The CALPHAD (calculation of phase diagrams) method is used in combination with selected experimental investigations to derive reaction paths in multicomponent systems. The method is illustrated by applying computerized thermodynamic databases and suitable software to explain quantitatively the thermal degradation of precursor-derived Si-C-N ceramics and the nitridation of titanium carbide. Reaction sequences in the Si 3 N 4 -SiC-TiC x N l-x -C-N system are illustrated by graphical representation of compatibility regions and indicated reaction paths. From these results the experimentally known microstructure development of TiC reinforced Si 3 N 4 ceramics is explained and quantitative information is provided to optimize the microstructure of such materials. The concept of reaction paths for the understanding of rapid solidification processes is shown by the example of AZ type Mg casting alloys. (orig.)

An in vitro comparison of root canal transportation by reciproc file with and without glide path.

Science.gov (United States)

Nazarimoghadam, Kiumars; Daryaeian, Mohammad; Ramazani, Nahid

2014-09-01

The aim of ideal canal preparation is to prevent iatrogenic aberrations such as transportation. The aim of this study was to evaluate the root canal transportation by Reciproc file with and without glide path. Thirty acrylic-resin blocks with a curvature of 60° and size#10 (2% taper) were assigned into two groups (n= 15). In group 1, the glide path was performed using stainless steel k-files size#10 and 15 at working length In group 2, canals were prepared with Reciproc file system at working length. By using digital imaging software (AutoCAD 2008), the pre-instrumentation and post-instrumentation digital images were superimposed over, taking the landmarks as reference points. Then the radius of the internal and external curve of the specimens was calculated at three α, β and γ points (1mm to apex as α, 3mm to apex as β, and 5mm to apex as γ). The data were statically analyzed using the independent T-test and Mann-Whitney U test by SPSS version 16. Glide path was found significant for only external curve in the apical third of the canal; that is, 5mm to apex (P=0.005). But in the other third, canal modification was not significant (P> 0.008). Canal transportation in the apical third of the canal seems to be significantly reduced when glide path is performed using reciprocating files.

Interactions of information transfer along separable causal paths

Science.gov (United States)

Jiang, Peishi; Kumar, Praveen

2018-04-01

Complex systems arise as a result of interdependences between multiple variables, whose causal interactions can be visualized in a time-series graph. Transfer entropy and information partitioning approaches have been used to characterize such dependences. However, these approaches capture net information transfer occurring through a multitude of pathways involved in the interaction and as a result mask our ability to discern the causal interaction within a subgraph of interest through specific pathways. We build on recent developments of momentary information transfer along causal paths proposed by Runge [Phys. Rev. E 92, 062829 (2015), 10.1103/PhysRevE.92.062829] to develop a framework for quantifying information partitioning along separable causal paths. Momentary information transfer along causal paths captures the amount of information transfer between any two variables lagged at two specific points in time. Our approach expands this concept to characterize the causal interaction in terms of synergistic, unique, and redundant information transfer through separable causal paths. Through a graphical model, we analyze the impact of the separable and nonseparable causal paths and the causality structure embedded in the graph as well as the noise effect on information partitioning by using synthetic data generated from two coupled logistic equation models. Our approach can provide a valuable reference for an autonomous information partitioning along separable causal paths which form a causal subgraph influencing a target.

Low level constraints on dynamic contour path integration.

Directory of Open Access Journals (Sweden)

Sophie Hall

Full Text Available Contour integration is a fundamental visual process. The constraints on integrating discrete contour elements and the associated neural mechanisms have typically been investigated using static contour paths. However, in our dynamic natural environment objects and scenes vary over space and time. With the aim of investigating the parameters affecting spatiotemporal contour path integration, we measured human contrast detection performance of a briefly presented foveal target embedded in dynamic collinear stimulus sequences (comprising five short 'predictor' bars appearing consecutively towards the fovea, followed by the 'target' bar in four experiments. The data showed that participants' target detection performance was relatively unchanged when individual contour elements were separated by up to 2° spatial gap or 200 ms temporal gap. Randomising the luminance contrast or colour of the predictors, on the other hand, had similar detrimental effect on grouping dynamic contour path and subsequent target detection performance. Randomising the orientation of the predictors reduced target detection performance greater than introducing misalignment relative to the contour path. The results suggest that the visual system integrates dynamic path elements to bias target detection even when the continuity of path is disrupted in terms of spatial (2°, temporal (200 ms, colour (over 10 colours and luminance (-25% to 25% information. We discuss how the findings can be largely reconciled within the functioning of V1 horizontal connections.

Transition paths in single-molecule force spectroscopy.

Science.gov (United States)

Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

2018-03-28

In a typical single-molecule force spectroscopy experiment, the ends of the molecule of interest are connected by long polymer linkers to a pair of mesoscopic beads trapped in the focus of two laser beams. At constant force load, the total extension, i.e., the end-to-end distance of the molecule plus linkers, is measured as a function of time. In the simplest systems, the measured extension fluctuates about two values characteristic of folded and unfolded states, with occasional transitions between them. We have recently shown that molecular (un)folding rates can be recovered from such trajectories, with a small linker correction, as long as the characteristic time of the bead fluctuations is shorter than the residence time in the unfolded (folded) state. Here, we show that accurate measurements of the molecular transition path times require an even faster apparatus response. Transition paths, the trajectory segments in which the molecule (un)folds, are properly resolved only if the beads fluctuate more rapidly than the end-to-end distance of the molecule. Therefore, over a wide regime, the measured rates may be meaningful but not the transition path times. Analytic expressions for the measured mean transition path times are obtained for systems diffusing anisotropically on a two-dimensional free energy surface. The transition path times depend on the properties both of the molecule and of the pulling device.

A career path in clinical pathways.

Science.gov (United States)

Bower, K A

1998-03-01

Much like the development of a clinical path, the creation of a career path requires knowledge of patterns of behavior, needs for standardized education and skill development, along with variance analysis and individualized care. This nationally known nursing entrepreneur tells the story of her involvement in the development of case management and clinical pathways and how she turned that into a successful business that has changed how patient care is managed nationally and internationally.

Experimental demonstration of spectrum-sliced elastic optical path network (SLICE).

Science.gov (United States)

Kozicki, Bartłomiej; Takara, Hidehiko; Tsukishima, Yukio; Yoshimatsu, Toshihide; Yonenaga, Kazushige; Jinno, Masahiko

2010-10-11

We describe experimental demonstration of spectrum-sliced elastic optical path network (SLICE) architecture. We employ optical orthogonal frequency-division multiplexing (OFDM) modulation format and bandwidth-variable optical cross-connects (OXC) to generate, transmit and receive optical paths with bandwidths of up to 1 Tb/s. We experimentally demonstrate elastic optical path setup and spectrally-efficient transmission of multiple channels with bit rates ranging from 40 to 140 Gb/s between six nodes of a mesh network. We show dynamic bandwidth scalability for optical paths with bit rates of 40 to 440 Gb/s. Moreover, we demonstrate multihop transmission of a 1 Tb/s optical path over 400 km of standard single-mode fiber (SMF). Finally, we investigate the filtering properties and the required guard band width for spectrally-efficient allocation of optical paths in SLICE.

comparative analysis and implementation of dijkstra's shortest path

African Journals Online (AJOL)

user

path problem requires finding a single shortest-path between given vertices s and t; ... Bridge in 1735, [5 – 10]. This problem led to the .... their advancements from new design paradigms, data structures ..... .

Identification of flow paths and quantification of return flow volumes and timing at field scale

Science.gov (United States)

Claes, N.; Paige, G. B.; Parsekian, A.

2017-12-01

Flood irrigation, which constitutes a large part of agricultural water use, accounts for a significant amount of the water that is diverted from western streams. Return flow, the portion of the water applied to irrigated areas that returns to the stream, is important for maintaining base flows in streams and ecological function of riparian zones and wetlands hydrologically linked with streams. Prediction of timing and volumes of return flow during and after flood irrigation pose a challenge due to the heterogeneity of pedogenic and soil physical factors that influence vadose zone processes. In this study, we quantify volumes of return flow and potential pathways in the subsurface through a vadose zone flow model that is informed by both hydrological and geophysical observations in a Bayesian setting. We couple a two-dimensional vadose zone flow model through a Bayesian Markov Chain Monte Carlo approach with time lapse ERT, borehole NMR datasets that are collected during and after flood irrigation experiments, and soil physical lab analysis. The combination of both synthetic models and field observations leads to flow path identification and allows for quantification of volumes and timing and associated uncertainties of subsurface return that stems from flood irrigation. The quantification of the impact of soil heterogeneity enables us to translate these results to other sites and predict return flow under different soil physical settings. This is key when managing irrigation water resources and predictions of outcomes of different scenarios have to be evaluated.

A Model Predictive Algorithm for Active Control of Nonlinear Noise Processes

Directory of Open Access Journals (Sweden)

Qi-Zhi Zhang

2005-01-01

Full Text Available In this paper, an improved nonlinear Active Noise Control (ANC system is achieved by introducing an appropriate secondary source. For ANC system to be successfully implemented, the nonlinearity of the primary path and time delay of the secondary path must be overcome. A nonlinear Model Predictive Control (MPC strategy is introduced to deal with the time delay in the secondary path and the nonlinearity in the primary path of the ANC system. An overall online modeling technique is utilized for online secondary path and primary path estimation. The secondary path is estimated using an adaptive FIR filter, and the primary path is estimated using a Neural Network (NN. The two models are connected in parallel with the two paths. In this system, the mutual disturbances between the operation of the nonlinear ANC controller and modeling of the secondary can be greatly reduced. The coefficients of the adaptive FIR filter and weight vector of NN are adjusted online. Computer simulations are carried out to compare the proposed nonlinear MPC method with the nonlinear Filter-x Least Mean Square (FXLMS algorithm. The results showed that the convergence speed of the proposed nonlinear MPC algorithm is faster than that of nonlinear FXLMS algorithm. For testing the robust performance of the proposed nonlinear ANC system, the sudden changes in the secondary path and primary path of the ANC system are considered. Results indicated that the proposed nonlinear ANC system can rapidly track the sudden changes in the acoustic paths of the nonlinear ANC system, and ensure the adaptive algorithm stable when the nonlinear ANC system is time variable.

Influence of a glide path on apical extrusion of debris during canal preparation using single-file systems in curved canals.

Science.gov (United States)

Topçuoğlu, H S; Düzgün, S; Akpek, F; Topçuoğlu, G; Aktı, A

2016-06-01

To evaluate the effect of a glide path on the amount of apically extruded debris during canal preparation using single-file systems in curved canals. Ninety extracted mandibular molar teeth were randomly assigned to six groups (n = 15 for each group) for canal instrumentation. Endodontic access cavities were prepared in each tooth. In three of the six groups, a glide path was not created whereas a glide path was created using PathFile instruments on the mesial canals of all teeth in the remaining three groups. The mesial canals of the teeth were then instrumented with the following single-file instrument systems: WaveOne, Reciproc and OneShape. Debris extruded apically during instrumentation was collected into pre-weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weight of the Eppendorf tubes for each group. The data obtained were analysed using one-way analysis of variance (anova) and Tukey's post hoc tests. The OneShape file was associated with less debris extrusion than the Reciproc and WaveOne files when canal instrumentation was performed without a glide path (P files (P > 0.05). There was no significant difference amongst the OneShape, Reciproc and WaveOne files when a glide path was created before canal preparation in curved root canals (P > 0.05). All systems extruded significantly less debris in groups with a glide path than in groups without a glide path (P < 0.05). All instruments were associated with apical extrusion of debris. Creating a glide path prior to canal instrumentation reduced the amount of apically extruded debris in curved canals. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Toward solving the sign problem with path optimization method

Science.gov (United States)

Mori, Yuto; Kashiwa, Kouji; Ohnishi, Akira

2017-12-01

We propose a new approach to circumvent the sign problem in which the integration path is optimized to control the sign problem. We give a trial function specifying the integration path in the complex plane and tune it to optimize the cost function which represents the seriousness of the sign problem. We call it the path optimization method. In this method, we do not need to solve the gradient flow required in the Lefschetz-thimble method and then the construction of the integration-path contour arrives at the optimization problem where several efficient methods can be applied. In a simple model with a serious sign problem, the path optimization method is demonstrated to work well; the residual sign problem is resolved and precise results can be obtained even in the region where the global sign problem is serious.

Path Following in the Exact Penalty Method of Convex Programming.

Science.gov (United States)

Zhou, Hua; Lange, Kenneth

2015-07-01

Classical penalty methods solve a sequence of unconstrained problems that put greater and greater stress on meeting the constraints. In the limit as the penalty constant tends to ∞, one recovers the constrained solution. In the exact penalty method, squared penalties are replaced by absolute value penalties, and the solution is recovered for a finite value of the penalty constant. In practice, the kinks in the penalty and the unknown magnitude of the penalty constant prevent wide application of the exact penalty method in nonlinear programming. In this article, we examine a strategy of path following consistent with the exact penalty method. Instead of performing optimization at a single penalty constant, we trace the solution as a continuous function of the penalty constant. Thus, path following starts at the unconstrained solution and follows the solution path as the penalty constant increases. In the process, the solution path hits, slides along, and exits from the various constraints. For quadratic programming, the solution path is piecewise linear and takes large jumps from constraint to constraint. For a general convex program, the solution path is piecewise smooth, and path following operates by numerically solving an ordinary differential equation segment by segment. Our diverse applications to a) projection onto a convex set, b) nonnegative least squares, c) quadratically constrained quadratic programming, d) geometric programming, and e) semidefinite programming illustrate the mechanics and potential of path following. The final detour to image denoising demonstrates the relevance of path following to regularized estimation in inverse problems. In regularized estimation, one follows the solution path as the penalty constant decreases from a large value.

Automatic path proposal computation for CT-guided percutaneous liver biopsy.

Science.gov (United States)

Helck, A; Schumann, C; Aumann, J; Thierfelder, K; Strobl, F F; Braunagel, M; Niethammer, M; Clevert, D A; Hoffmann, R T; Reiser, M; Sandner, T; Trumm, C

2016-12-01

To evaluate feasibility of automatic software-based path proposals for CT-guided percutaneous biopsies. Thirty-three patients (60 [Formula: see text] 12 years) referred for CT-guided biopsy of focal liver lesions were consecutively included. Pre-interventional CT and dedicated software (FraunhoferMeVis Pathfinder) were used for (semi)automatic segmentation of relevant structures. The software subsequently generated three path proposals in downward quality for CT-guided biopsy. Proposed needle paths were compared with consensus proposal of two experts (comparable, less suitable, not feasible). In case of comparable results, equivalent approach to software-based path proposal was used. Quality of segmentation process was evaluated (Likert scale, 1 [Formula: see text] best, 6 [Formula: see text] worst), and time for processing was registered. All biopsies were performed successfully without complications. In 91 % one of the three automatic path proposals was rated comparable to experts' proposal. None of the first proposals was rated not feasible, and 76 % were rated comparable to the experts' proposal. 7 % automatic path proposals were rated not feasible, all being second choice ([Formula: see text]) or third choice ([Formula: see text]). In 79 %, segmentation at least was good. Average total time for establishing automatic path proposal was 42 [Formula: see text] 9 s. Automatic software-based path proposal for CT-guided liver biopsies in the majority provides path proposals that are easy to establish and comparable to experts' insertion trajectories.

Which coordinate system for modelling path integration?

Science.gov (United States)

Vickerstaff, Robert J; Cheung, Allen

2010-03-21

Path integration is a navigation strategy widely observed in nature where an animal maintains a running estimate, called the home vector, of its location during an excursion. Evidence suggests it is both ancient and ubiquitous in nature, and has been studied for over a century. In that time, canonical and neural network models have flourished, based on a wide range of assumptions, justifications and supporting data. Despite the importance of the phenomenon, consensus and unifying principles appear lacking. A fundamental issue is the neural representation of space needed for biological path integration. This paper presents a scheme to classify path integration systems on the basis of the way the home vector records and updates the spatial relationship between the animal and its home location. Four extended classes of coordinate systems are used to unify and review both canonical and neural network models of path integration, from the arthropod and mammalian literature. This scheme demonstrates analytical equivalence between models which may otherwise appear unrelated, and distinguishes between models which may superficially appear similar. A thorough analysis is carried out of the equational forms of important facets of path integration including updating, steering, searching and systematic errors, using each of the four coordinate systems. The type of available directional cue, namely allothetic or idiothetic, is also considered. It is shown that on balance, the class of home vectors which includes the geocentric Cartesian coordinate system, appears to be the most robust for biological systems. A key conclusion is that deducing computational structure from behavioural data alone will be difficult or impossible, at least in the absence of an analysis of random errors. Consequently it is likely that further theoretical insights into path integration will require an in-depth study of the effect of noise on the four classes of home vectors. Copyright 2009 Elsevier Ltd

Continuous-Curvature Path Generation Using Fermat's Spiral

Directory of Open Access Journals (Sweden)