Track Paths Research Articles

Visually encoding orthogonal planar graph drawings as graph mazes: An eye tracking study

There are various styles to visually represent relational data in the form of node-link diagrams. In particular, for planar graphs we can find orthogonal node-link diagrams consisting of links bending only at ninety degrees a successful and prominent variant. One of the benefits of such drawings is the tracking of longer paths through a network with the eyes due to their limited number of link orientations, changes, and variations, but on the negative side the links can have arbitrary bending shapes. In this article we developed a novel way to visualize such orthogonal planar drawings by making use of mazes that look more natural to the human eye due to the street-like visual metaphor that many people are familiar with. Tracking paths is one of the major tasks in such graph visualizations, similar to orthogonal node-link diagrams, however, we argue that mazes are a more natural way to find paths. To get insights in the visual scanning behavior when reading graph mazes we conducted a comparative eye tracking study with 26 male versus female participants of different experience levels while also alternating between orthogonal node-link drawings and graph mazes as well as different graph size levels. The major result of this comparative study is that the participants can track paths in both representation styles, including a geodesic path tendency in their visual search behavior, but typically have a longer fixation duration at branching nodes and locations in the mazes that lead to opposite directions to the geodesic path tendency, maybe the viewers had to start a reorientation phase in their visual scanning behavior. We also found out that the size, that is the number of graph vertices has an impact on the visual scanning behavior for both orthogonal node-link diagrams as well as street-like maze representations, but for the mazes we found this impact to be less strong (in terms of the eye movement data metrics fixation durations and saccade lengths) compared to the node-link diagrams. To conclude the article, we discuss limitations and scalability issues of our approach. Moreover, we give an outlook and future work for possible extensions.

PO-02-212 TWISTED FIBROTICALLY-INSULATED MYOBUNDLES CREATE THE COMMON TRACK AND PIVOTING POINTS FOR REENTRANT DRIVERS MAINTAINING PERSISTENT AF IN-VIVO

Localized reentrant drivers have been suggested to maintain persistent atrial fibrillation (perAF). However, their existence, electrophysiological mechanisms, and structural substrates in-vivo are controversial. Define AF driving mechanism in-vivo and ex-vivo in a perAF canine model. A clinically relevant canine model (n=5) of self-sustained (4 months) perAF was developed to study AF maintaining mechanisms both in-vivo and ex-vivo by integrated 3D imaging, including high-resolution near-infrared optical mapping (NIOM, 0.3-0.5mm resolution), contrast-enhanced magnetic resonance imaging (CE-MRI, 0.15mm resolution). Transmural fibrosis was validated with histology. CE-MRI was used to quantitatively analyze 3D atrial structure, including transmural fiber orientation and fibrosis content in the sub-epi, intramural, and sub-endocardial layers. In all canine models (n=5), sequential in-vivo to ex-vivo sub-surface NIOM and 3D CE-MRI revealed that the self-sustained perAF was primarily maintained by localized reentrant drivers with temporal stability 53±17% (n=10), which recurrent on the same arrhythmogenic hubs. The 3D structure of the arrhythmogenic driver hubs includes a common intramural reentry track and multiple return paths formed by fibrotically-insulated bundles. The in-vivo spatio-temporal activation patterns of reentrant drivers were preserved ex-vivo (Figure A), including driver AFCL (91±7 ms vs 96±12 ms, p>0.05) and temporal driver stability (51±8% vs 52±6%, n=4, p>0.05). Targeted ablation of the driver reentrant tracks terminated or converted AF to slower tachycardia. Quantitative CE-MRI analysis of 3D myofiber orientations revealed that the transmural fiber twist along the common reentry tracks and pivoting points is greater than in non-driver regions (Figure B-C). The driver reentrant tracks had increased interstitial fibrotic strands and significantly higher intramural fibrosis than the neighboring non-driver regions (Figure D-E). Our results provide in-vivo proof-of-concept that spatially stable reentrant drivers are a mechanism of perAF maintenance. Intramural fibrotic strands and fibrotically-insulated myobundles in regions with the highest transmural myofiber twist which may form the common tracks and pivoting points for return paths of the spatially-stable reentrant AF driver.

Tropical Cyclone Simulations with WRF Using High Performance Computing

Tropical cyclone (TC) Bud occurred over the Eastern Pacific Ocean from 9 June to 16 June 2018 reaching, a category-4 hurricane status (H4) due to its strong sustained winds and gusts. In this study, we simulate this TC to reproduce its track path, direction, and strength to determine the best model physics configurations that weather agencies could use to forecast TC tracks over the Eastern Pacific Ocean, adjacent to the Mexican coastline. To achieve this goal, the sensitivity for the impact of different microphysics and cumulus parameterization schemes is carried out through high-performance computer simulations, with the WRF model using the cluster CÓDICE B2 at Centro de Investigación en Computación (CIC) of the Instituto Politécnico Nacional (IPN). The realism of the TC for the different schemes is assessed by comparing the simulations and the best track data taken from the National Hurricane Center (NHC-NOAA). The NCEPGFS forecast data is used as initial and boundary conditions. The evolution of wind and minimum pressure at sea level for the different physics combination runs are also compared with the best track data. We found that the track paths and intensities improve when Sea Surface Temperature (SST) is allowed to evolve with the modeled atmosphere via computer simulations.

Vertical and horizontal soil stresses beneath a modern combine harvester: Measurements and modelling

AbstractVehicle traffic‐induced subsoil compaction has negative influences on soil functions and ecosystems, which may cause the degradation of farmland. Rubber tracks are recommended for use on modern large agricultural vehicles due to its low ground pressure as compared to tyres. However, few studies have discussed the potential of the rubber tracks to reduce subsoil stress. In this study, we investigated the magnitude and distribution of soil stress below a rubber track and a tyre for a range of traffic velocities. The vertical and horizontal soil stresses were measured under the centrelines of the rubber track and tyre paths at a depth of 0.35 m by transducers buried in the soil. The SoilFlex model was adopted to simulate soil stress in the soil profile. Vertical stress was distributed with one peak under the tyre and multiple peaks under the rubber track. Horizontal stress exhibited one peak before and one peak after the passing of the axle. The maximum vertical and horizontal stresses were approximately 3.4‐ and 2.0‐times higher, respectively, under the tyre than under the rubber track, indicating greater effectiveness of the rubber track in reducing the vertical stress than reducing horizontal stress. Both vertical and horizontal stresses presented a downward trend as the vehicle velocity increased.

Application of an improved spatio-temporal identification method of flash droughts

Flash droughts are regional phenomena that can manifest in large areas with rapid intensification for a period of time. Few studies have considered the spatial pathways of flash droughts or their drought period. This study uses the five criteria based on the standardized evaporative stress ratio (SESR) method to identify flash droughts, and when a SESR value recovers to the 20th percentile, the flash drought is considered to terminate. To define spatially continuous flash droughts accurately, the usual order of first calculating drought patches and then identifying flash droughts is reversed to first identify flash droughts on the grid and then determine flash drought patches. In addition, this study tracks the spatial paths of flash droughts via centroid transfers of flash drought patches. Using MOD16 data, the methodology is evaluated by analyzing the regional characteristics of flash droughts in the Huaibei Plain of China from 2001 to 2019. The flash droughts in this region most frequently tracked in the northeast and west. The average flash drought duration was 31 days, of which the rapid intensification period was 18 days and drought period was 14 days. Flash drought events in this region mostly occurred in May, August and October, and east to west transition and non-transitions, which accounted for 44% and 22%, respectively, were the main spatial track paths. Only 26% of flash drought events transitioned to long term drought events. This study expands our knowledge of the evolution process of flash droughts to space-time dimensions, which is essential for flash droughts early warning and agricultural water management.

Rural Track Paths on Low-Volume Roads in Austria

The rural road network in Austria consists of all roads that are neither federal nor provincial roads and serve the purpose of enabling access to the rural area. This low-volume road network includes all municipal roads, farm roads, and forest roads. The total length of these roads amounts to approximately 160,000 km or 80% of the total Austrian road network. The responsibility for construction and maintenance of this rural road network in Austria is split between private persons and public authorities. Within these special circumstances a new technical design guideline for rural track paths has been elaborated in Austria. During this elaboration the experiences and know-how from Germany and Switzerland have been analyzed and taken into consideration. The main part of the paper deals with this new design guideline and shows an innovative way to handle activities in construction and maintenance of low-volume roads realized as single-lane rural track paths. These track paths consist of two load-carrying tracks constructed of asphalt, concrete, surface treatment, or block pavers. The obvious advantages of this tracked paving approach are to reduce the impact of impervious surface types and the impact on the environment. What makes this guideline unique is the fact that it is the first of its kind in Austria to encompass all aspects of planning, design, practical construction, and implementation of rural track paths on low-volume roads.

Continuous track paths reveal additive evidence integration in multistep decision making

Multistep decision making pervades daily life, but its underlying mechanisms remain obscure. We distinguish four prominent models of multistep decision making, namely serial stage, hierarchical evidence integration, hierarchical leaky competing accumulation (HLCA), and probabilistic evidence integration (PEI). To empirically disentangle these models, we design a two-step reward-based decision paradigm and implement it in a reaching task experiment. In a first step, participants choose between two potential upcoming choices, each associated with two rewards. In a second step, participants choose between the two rewards selected in the first step. Strikingly, as predicted by the HLCA and PEI models, the first-step decision dynamics were initially biased toward the choice representing the highest sum/mean before being redirected toward the choice representing the maximal reward (i.e., initial dip). Only HLCA and PEI predicted this initial dip, suggesting that first-step decision dynamics depend on additive integration of competing second-step choices. Our data suggest that potential future outcomes are progressively unraveled during multistep decision making.

A Nonlinear Model to Predict Drivers’ Track Paths Along a Curve

This study proposes a prediction model about the trajectories a vehicle, in isolated conditions, along a curve of a road. As we know, the road environment induces stress on users and, under certain conditions, influences driving behavior. It is of advantage then, to isolate and identify those conditions from among the numerous variables, which are actually the most significant so as to prevent or mitigate the occurrence of dangerous maneuvers. On the basis of an experiment performed using an instrumented vehicle, we collected a data base to which we subsequently applied Neuro-Fuzzy techniques for the selection of the most representative variables. We then used these data to prepare a nonlinear dynamic Hammerstein-Wiener’s model able to predict the track paths along curves. The findings were encouraging since almost all the results obtained from the validation checks proved satisfactory. This research is the first step in the identification of complex systems and could be applied in road safety measures and design of new and existing roads.

The effect of artificial light on wildlife use of a passage structure

Barriers to animal movement can isolate populations, impacting their genetic diversity, susceptibility to disease, and access to resources. Barriers to movement may be caused by artificial light, which is known to disrupt bird, sea turtle, and bat behavior, but few studies have experimentally investigated the effects of artificial light on movement for a suite of terrestrial vertebrates. Therefore, we studied the effect of ecological light pollution on animal usage of a bridge under-road passage structure. On a weekly basis, sections of the structure were subjected to different light treatments including no light added, followed by a Reference period when lights were off in all the structure sections. Sand track data revealed use by 23 mammals, birds, reptiles and amphibians, nine of which had >30 tracks for species-level analysis. Columbia black-tailed deer (Odocoileus hemionus columbianus) traversed under unlit bridge sections much less when neighboring sections were lit compared to when none were, suggesting avoidance due to any nearby presence of artificial light. Similarly, deer mouse (Peromyscus maniculatus) and opossum (Didelphis virginiana) track paths were less frequent in the lit sections than the ambient. Crossing was correlated with temporal or spatial factors but not light for three of the other species. These findings suggest that artificial light may be reducing habitat connectivity for some species though not providing a strong barrier for others. Such information is needed to inform mitigation of habitat fragmentation in the face of expanding urbanization.

Prediction of road track paths by a fuzzy model

ABSTRACTThis research proposes a fuzzy model built to predict the track paths of a motor vehicle on a two-lane road and two-way traffic. The purpose of this study stems from the awareness that the position of the vehicle within the cross-section hardly coincides with the axis of the lane but deviates from this one because of some conditions generally not provided in the road standards. To solve this problem, the authors prepared an instrumented vehicle, measuring many variables during some trials in a rural road located in Sicily, Italy. The resulting database was treated at first with subtractive clustering techniques to correctly size the membership functions and rules without the subjective help of an analyst. Therefore, the fuzzy model was built only on the basis of the measured data, and the result was the position of the vehicle within the cross-section of the examined road. This research can help the analyst to look for the real cause of user's misbehavior even when the variables involved are fully respectful with the road standard to modify or eliminate disturbing elements in the understanding of the road by the users.

Frame frequency prediction for Risley-prism-based imaging laser radar.

A dual-wedge scanner has potential applications in laser imaging radar. To realize fast scanning imaging without a blind region, the rotation rates of the wedges have to be controlled to perform beam scanning along appropriate track paths. The first-order paraxial approximation method is employed to investigate the 2D scan patterns and path density for different angular frequency ratios of the wedges rotating steadily in the same and opposite directions. The frame rate of no-blind-region scanning imaging is estimated in terms of the imaging coverage requirement. The internal relations between the rotation rates, the instantaneous field of view (IFOV), and the imaging velocity are revealed. The results show that the spiral scanning trace, resulting from co-rotating wedges, is dense in the center and sparse at the edge of the scanning field. The reverse results can be obtained for the rosette scanning trace, resulting from counter-rotating wedges. The denser the scanning trace is, the longer the scan period is. The faster the wedges rotate and the wider the IFOV is, the higher the frame rate is. When the ratio of the width of IFOV to the angular radius of the scanning field is 0.15, the frame rate of no-blind-region spiral scanning imaging can be up to 18 fps for wedge rotation rate of 12000 r/min, and that for rosette scanning imaging can be up to 20 fps.

A 3D absolute nodal coordinate finite element model to compute the initial configuration of a railway catenary

In this paper we propose a method of finding the initial equilibrium configuration of cable structures discretized by finite elements applied to the shape-finding of the railway overhead system. Absolute nodal coordinate formulation finite elements, which allow for axial and bending deformation, are used for the contact and messenger wires. The other parts of the overhead system are discretized with non-linear bars or equivalent springs. The proposed method considers the constraints introduced during the assembly of the catenary, such as the position of droppers, cable tension, and height of the contact wire. The formulation is general and can be applied to different catenary configurations or transitions both in 2D and 3D with straight or curved track paths. A comparison of the results obtained for reference catenaries in the bibliography is also included.

Functional habitat connectivity for beach mice depends on perceived predation risk

Landscape features that promote animal movement contribute to functional habitat connectivity. Factors that affect the use of landscape features, such as predation risk, may alter functional connectivity. We identify factors important to functional habitat connectivity by quantifying movement patterns of the Santa Rosa beach mouse (Peromyscus polionotus leucocephalus) in relation to landscape features and by examining how ambient perceived predation risk, which is altered by moon phase, interacts with landscape features. We use track paths across the sand to relate the probability that beach mice cross gaps between vegetation patches to gap width, patch quality, landscape context and moon phase. Overall activity levels were lower during full versus new moon nights, demonstrating that beach mice respond negatively to moonlight. Gap crossing was more likely during new moon nights (25 % of gaps crossed vs. 7 % during full moon nights), and across narrower gaps ( 11.75 m2). This study suggests that vegetation recovery is necessary for functional connectivity in post-hurricane landscapes commonly inhabited by beach mice and provides initial guidelines for restoring landscape connectivity. More broadly, this study highlights the importance of considering predation risk when quantifying landscape connectivity, as landscape features that facilitate connectivity when predation risk is low may be ineffective if predation risk increases over time or across space.

Study on Vehicle Track Model in Road Curved Section Based on Vehicle Dynamic Characteristics

Plenty of experiments and data analysis of vehicle track type in road curved section show that the deviation and the crossing characteristics of vehicle track paths are directly related to the driving stability and security. In this connection, the concept of driving trajectory in curved section was proposed, six track types were classified and defined, and furthermore their characteristic features were determined. Most importantly, considering curve geometry and vehicle dynamic characteristics, each trajectory model was established, respectively, and the optimum driving trajectory models were finally determined based on the crucial factors of vehicle yaw rate, which was also the most important factor that impacts vehicle’s handling stability. Through it all, MATLAB was used to simulate and verify the correctness of models. Finally, this paper comes to the conclusion that normal trajectory and cutting trajectory are the optimum driving trajectories.

Study on Driving Dangerous Area in Road Curved Section Based on Vehicle Track Characteristics

Plenty of experiments and data analysis of vehicle track type in road curved section show that the deviation and the crossing characteristics of vehicle track paths are directly related to the driving stability and security. In this paper, the concept of driving dangerous area in curved section was proposed based on the vehicle track characteristics according to driving behavior decision making and accident probability. Taking the observation data of passenger cars as the representative, the vehicle track paths deviation regularity per measurement direction were analyzed by SPSS under the condition of different radius and different road cross section. The distribution probability of different track type and the accident probability calculation methods and results between opposite direction vehicles were given based on the track characteristics.

A discussion of the links between solar variability and high‐storm‐surge events in Venice

This study explores the long‐term frequency variability of high‐surge events (HSEs) in the North Adriatic, the so‐called acqua alta, which, particularly during autumn, cause flooding of the historical city center of Venice. The period 1948–2008, when hourly observations of sea level are available, is considered. The frequency of HSEs is correlated with the 11 year solar cycle, solar maxima being associated with a significant increase in the October‐November‐December HSE frequency. The seasonal geopotential height pattern at 1000 hPa (storm surge pattern; SSP) associated with the increased frequency of HSEs is identified for the whole time period and found to be similar to the positive phase of the main variability mode of the regional atmospheric circulation (empirical orthogonal function 1; EOF1). However, further analysis indicates that solar activity modulates the spatial patterns of the atmospheric circulation (EOF) and the favorable conditions for HSE occurrence (SSP). Under solar maxima, the occurrence of HSEs is enhanced by the main mode of regional atmospheric variability, namely, a large‐scale wave train pattern that is symptomatic of storm track paths over northern Europe. Solar minima reveal a substantially different and less robust SSP, consisting of a meridionally oriented dipole with a preferred southward path of storm track activity, which is not associated with any dominant mode of atmospheric variability during low‐solar periods. It is concluded that solar activity plays an indirect role in the frequency of HSEs by modulating the spatial patterns of the main modes of atmospheric regional variability, the favorable patterns for HSE occurrence, and their mutual relationships, so that constructive interaction between them is enhanced during solar maxima and inhibited in solar minima.

Track Behavior in Curve Areas: Attempt at Typology

In contrast to the usual descriptions of driving behavior in curve areas in terms of speeds, this research project investigated track behavior. In this connection, a classification of the driving processes according to the type of the track paths along curves was developed; six track types were defined and their characteristic features were determined, and the frequency of the individual track types which occur was evaluated. Correlations between track behavior, curve geometry, and accidents in curves were also examined. For these purposes, data were collected for curves on two-lane highways in rural areas (speed limit 80km∕h). The measurements were made with specially developed “measuring posts,” a tool that makes it possible to detect driving direction, vehicle lengths, spot speeds, as well as transverse distances of the vehicles from the edge of the pavement. This pilot investigation confirmed that different patterns of track paths do exist in curves, and that the frequency of the individual track types differs considerably from curve to curve. The track types also have very different characteristics.

Tracking with distributed sets of proximity sensors using geometric invariants

We propose a new approach to forming an estimate of a target track in a distributed sensor system using very limited sensor information. This approach uses a central fusion system that collects only the peak energy information from each sensor and assumes that the energy attenuates as a power law in range from the source. A geometrical invariance property of the proximity of the distributed sensors relative to a target track is used to generate potential target track paths. Numerical simulation examples are presented to illustrate the practicality of the technique.

Influence of trapping on silicon microstrip detector design and performance

New systematic measurements of effective carrier trapping times were used as an input to simulate the operation of an irradiated silicon strip detector. The dependence of charge-collection efficiency (CCE) on bias voltage, magnetic field, irradiation particle type, fluence, and detector design was investigated. It was observed that irradiated detectors processed on standard n-silicon material with n/sup +/ strips performed better than those with p/sup +/ strips. At /spl Phi//sub eq/=2/spl times/10/sup 14/ cm/sup -2/, the difference in CCE was around 10% at voltages well above V/sub FD/ and even larger for lower voltages. A few percent difference in CCE for different track paths across the strip was observed. The effective Lorentz angle was found to be independent of the irradiation level. A nonnegligible amount of charge also appears on neighboring strips as a consequence of charge trapping. The influence of detector thickness and strip width on induced charge was also studied.

Alpha-particle spectroscopy with TASTRAK (CR-39 type) plastic, and its application to the measurement of hot particles

Two applications of TASTRAK plastic to measurement of alpha activity are described. (1) Alpha particle spectroscopy is possible by automated analysis of etched alpha particle tracks in TASTRAK (CR-39) type plastic. The method is based on the measurement of two geometric parameters of etched tracks, the minor axis, and the diameter of the etched out track end. Accurate measurement of these two parameters allows reliable separation of tracks according to alpha particle energy, with a FWHM of 80–110 keV (1.33–2%) over an energy band of 1.1 MeV. Within this band the intrinsic measurement efficiency is as high as 0.75, a critical factor for possible low level measurement applications. The results indicate that a basis exists for a robust working method for alpha particle spectroscopy in TASTRAK plastic. (2) A method is being developed for simultaneous measurement of size and activity of alpha emitting hot particles. A hot particle is defined here as a volume of alpha active material, which may be attached to an inert particle. Hot alpha emitting particles produce characteristic radial clusters of tracks in etched TASTRAK. Automated image analysis of each track yields the following values: track co-ordinate, azimuth angle, dip angle, and track range. With these values, track paths can be projected above the plastic surface. A multi-step procedure is described which calculates three parameters for a hot particle: the alpha activity, the physical size and distance of the particle above the plastic. The method is demonstrated as applied to anthropogenic hot particles in the Chernobyl region, Ukraine, and to natural uranium hot particles in soil from Bristol, UK.