Average Track Length Research Articles

Convolutional Neural Network-Based Approximation of Coverage Path Planning Results for Parking Lots

Parking lots have wide variety of shapes because of surrounding environment and the objects inside the parking lot, such as trees, manholes, etc. In the case of paving the parking lot, as much area as possible should be covered by the construction vehicle to reduce the need for manual workforce. Thus, the coverage path planning (CPP) problem is formulated. The CPP of the parking lots is a complex problem with constraints regarding various issues, such as dimensions of the construction vehicle and data processing time and resources. A strategy based on convolutional neural networks (CNNs) for the fast estimation of the CPP’s average track length, standard deviation of track lengths, and number of tracks was suggested in this article. Two datasets of different complexity were generated to analyze the suggested approach. The first case represented a simple case with a working polygon constructed out of several rectangles with applied shear and rotation transformations. The second case represented a complex geometry generated out of rectangles and ellipses, narrow construction area, and obstacles. The results were compared with the linear regression models, with the area of the working polygon as an input. For both generated datasets, the strategy to use an approximator to estimate outcomes led to more accurate results compared to the respective linear regression models. The suggested approach enables us to have rough estimates of a large number of geometries in a short period of time and organize the working process, for example, planning construction time and price, choosing the best decomposition of the working polygon, etc.

Impacts of praseodymium (III, IV) oxide on physical, optical, and gamma-ray shielding properties of boro-silicate glasses

The present work aims to study the influence of Pr3+ ions on the structural, optical, and gamma-ray shielding properties of borosilicate glasses. Therefore, a new series of boro-silicate glass reinforced by small concentrations of praseodymium oxide varied between 0 and 1 mol.%. The XRD was utilized to emphasize the amorphous phase of the fabricated glasses. Moreover, UV–Vis Spectroscopy is used to detect the absorbance which is used to evaluate the energy band gap (Eg, eV) and Urbach energy (Eu, eV). The optical results showed that the energy band gap for direct transition decreased from 3.508 eV to 3.086 eV and decreased for the indirect transition from 3.086 eV to 2.879 eV with raising the Pr6O11 concentration in the fabricated glasses. The Monte Carlo simulation method was applied to simulate the average track length of γ-photons inside the fabricated boro-silicate. The linear attenuation coefficient for the fabricated boro-silicate glasses was enhanced by factors of 2.56 times (at 26 keV), 2.68 (at 103 keV), and 1.05 times (at 511 keV) with raising the Pr6O11 concentration between 0 and 1 mol.%. The result depicts no considerable change in the γ-ray shielding properties observed at γ energy ≥511 keV.

Theoretical Examination of the Radiation Protecting Properties of CaTiO3 Material Sintered at Different Temperatures

This research is devoted to studying the radiation-protecting characteristics of calcium titanate (CaTiO3) perovskite-based ceramic material. The ceramics were made by the solid-state reaction method (SSRM) and treated at temperatures of 1300 °C, 1200 °C, and 1100 °C. The structural characteristics of the ceramics were analyzed by XRD and FT-IR. The results indicated a CaTiO3 phase formation with an orthorhombic structure. The size of the crystallites was in the range of 27–36 nm and was found to increase as the temperatures increased. The relative density showed an increase from 93% to 96% as the temperatures varied from 1100 °C to 1300 °C. The impact of temperature on the radiation-protecting characteristics of the CaTiO3 ceramic was assessed using the Monte Carlo simulation (MCS). There was a slight decrease in the γ-photons average track length with a raising of the temperature. At a γ-photon energy of 0.662 MeV, the γ-photons’ average track lengths diminished from 3.52 cm to 3.38 cm by raising the temperature from 1100 °C to 1300 °C. The illustrated decrease in the γ-photons average track length affected the linear attenuation coefficient (µ) where the µ increased from 0.28 to 0.30 cm−1 with a rising temperature from 1100 °C to 1300 °C.

Study of charge carrier transport properties and lifetimes in HR GaAs:Cr with Timepix3

The response of a Timepix3 (256 × 256 pixels, pixel pitch 55 μm) detector with a 500 μm thick HR GaAs:Cr sensor was studied in proton beams of 125 MeV at the Danish Centre for Particle Therapy in Aarhus, Denmark and in a 120 GeV/c pion beam at the Super-Proton Synchrotron (SPS) at CERN. The sensor was biased at different voltages and irradiated at different angles. The readout chip was configured to operate in electron and hole collection modes. Measurements at grazing angles allowed to see elongated tracks with well-defined impact and exit points, so that charge carrier production depths could be determined in each pixel. We extracted the charge collection efficiencies and the charge carrier drift times as a function of the distance to the pixel plane. It was found that measured proton tracks are shorter in hole collection than in the case of electron collection, which is explained by the shorter lifetime of holes. At an angle of 60 degrees with respect to the sensor normal, the average track length in hole collection was ∼700 μm and 950 μm in electron collection mode. To understand the experimental findings, models describing the properties of HR GaAs:Cr were implemented into the Allpix2 simulation framework. We added previously presented experimental results describing the dependence of the electron drift velocity on the electric field and validated the response by comparing measurement and simulation for various X- and gamma-ray sources in the energy range of 10–60 keV. By comparison of the experimental and the simulated results, the mobility μ h and the lifetime of holes τ h were estimated as μ h = (320 ± 10) cm2/V/s and τ h = (4.5 ± 0.5) ns.

Neurite orientation dispersion and density imaging in evaluation of high-grade glioma-induced corticospinal tract injury

PurposeTo evaluate the application of neurite orientation dispersion and density imaging (NODDI) to brain glioma-induced corticospinal tract (CST) injury. Material and methodsTwenty-four patients with high-grade glioma (HGG) in or adjacent to the CST pathway and 12 matched healthy subjects underwent structural and diffusion MRI. The CSTs were reconstructed on the both sides. The CST features including morphological features (track number, average track length and track volume) and the diffusion parameter values including fractional anisotraphy (FA), mean diffusivity (MD), intracellular volume fraction (ICVF), isotropic or free water volume fraction (ISOVF) and orientation dispersion index (ODI) along the CST were calculated. The CST features were compared between the affected and healthy side for HGG patients and between the left and right side for healthy subjects. The relative CST features were compared across the healthy subjects, patients with motor weakness and patients with normal muscle strength. Receiver operating characteristic (ROC) curve was applied to evaluate the performance of each relative CST characteristic for HGG-induced CST changes. ResultsCompared with the CST features on the healthy side, the track number, track volume and FA along the CST changed significantly on the affected side for HGG patients (p < 0.05 for all), whereas MD and ICVF changed significantly on the affected side only for HGG patients with motor weakness (p = 0.012 for both). In patients with motor weakness, the relative MD was significantly higher (p < 0.001), whereas the relative FA and ICVF was significantly lower (p = 0.002 and <0.001) than those in patients with normal muscle strength. The relative ICVF had a similar area under curve (AUC) to that of MD (AUC=0.953 and 0.969). Compared with the relative CST features in the healthy subjects, only the relative ICVF was significantly lower in HGG patients with normal muscle strength (p = 0.012). ConclusionsNODDI seems to be useful in reflecting the HGG infiltration to CST, and can evaluate the CST destruction with a performance similar to DTI by providing additional information about neurite density for HGG-induced CST injury.

Vehicle Trajectory Prediction Method based on Deep Learning under the background of Internet of Vehicles

With the expansion of the Internet, big data and other industries, mobile devices are almost used in all aspects of life. The location-based service platform provides convenient services for users, but also obtains a large number of user history tracks. Through the trajectory data mining, we can extract valuable user behavior information, help user’s better plan routes, and can be applied in urban traffic management and commercial advertising layout and other scenarios. In this paper, a trajectory prediction algorithm based on deep learning is proposed to solve the problem of vehicle trajectory prediction. In this paper, the vehicle passing records are preprocessed and the vehicle trajectory is generated. The trajectory is transformed into the discrete position sequence of the vehicle as the input of the algorithm. Then the space-time multi-dimensional features of vehicle trajectory are extracted. Finally, a trajectory prediction algorithm based on deep learning is constructed. The batch size is 256 and the average track length of training set is 46.45. The convolution neural network and deep bidirectional long-term memory network are fused to learn the local and global information of vehicle trajectory. The research shows that compared with traditional machine learning, deep learning has achieved better results in various fields of computer vision because of its powerful representation ability. The visual perception algorithm based on deep learning can accurately analyze the regularity of vehicle movement and make accurate prediction of vehicle moving trajectory in the future.

A comprehensive examination of zinc-boro-vanadate glass reinforced with Ag2O in physical, optical, mechanical, and radiation shielding aspects

This study explored the zinc-boro-vanadate (ZBV) glass reinforced with Ag2O to show radiation shielding competencies. A glass system with composition 20ZnO-55B2O3-(25-x)V2O5-xAg2O, where x ranges from 0 to 10 with the steps of 2.5 mol%, was designed. Some physical and optical calculations were employed to figure out glass density (ρglass), molar volume (Vm), oxygen molar volume (OMV), oxygen packing density (OPD), refractive index (n), dielectric constant (ϵ), and metalization criterion (M) for the glass system of ZBV0 to ZBV10. According to the findings, one can specify that the increasing content of Ag2O enhanced both the physical and optical features of the ZBV series. The glass density was increased from 3.3150 to 3.6930 g/cm3, while the refractive index was raised from 3.0693 to 3.1216 with the insertion ratio of Ag2O from 0 to 10 mol%. The ZBV10 sample having the maximum Ag2O of 10 mol% ensured to improve physical and optical properties. The shielding properties of the examined glass samples were investigated to evaluate their ability for radiation protection purposes. The Monte Carlo N-Particle Transport Code 5 (MCNP-5) was utilized to assess the projected gamma photons' average track length on the investigated glass samples. Then, the linear attenuation coefficient (LAC), half-value layer (HVL), transmission factor (TF), and radiation protection efficiency (RPE) were calculated based on the simulated gamma photons' average track length. The obtained results showed that the highest LAC values increased from 71.999 to 91.979 cm−1. Moreover, the thicker HVL decreased from 9.869 to 9.332 cm−1, increasing the Ag2O insertion ratio between 0 and 10 mol%, respectively. The mentioned data confirmed that substitution of the V2O5 by the Ag2O enhance the gamma-ray shielding capacity of the explored series of glass.

Neuronal trafficking dynamics and regulators

AbstractBackgroundNeurons are highly polarized cells continuously relying on intracellular transport, through which they communicate with the external world. Among the somatodendritic and axonal compartments many proteins with different functions are sorted to reach long distances. The relevance of neuronal transport in ensuring cell development and homeostasis maintenance raises a big interest on this topic. Moreover, several neurodegenerative diseases, such as Alzheimer’s or Amyotrophic Lateral Sclerosis, exhibit significant axonal pathology, where transport impairment seems to have a crucial influence. However, the role of this process in neurodegeneration, remains poorly understood. In this study we aim to characterize neuronal transport dynamics of specific proteins, and the molecular machinery regulating this process. Furthermore, we aim to explore transport from the pathological point of view, evaluating the effect that mutant proteins (e.g. TDP43‐related) may have on it.MethodHuman Neural Stem Cells derived neurons were differentiated for 30 DIV. Plasmids encoding for different GFP‐coupled proteins were designed to express those who are involved in main neuronal functions (e.g. synaptic activity) and transfected in neurons. Time‐lapse movies of cargoes were acquired to detect changes in movement. Data analysis was performed using object segmentation and tracking algorithms. Raw data were processed to describe the main motion parameters: average velocity, directionality, track length, and others. Post‐imaging Immunocytochemistry was performed to assess cargoes localization and discriminate between axonal and dendritic transport.ResultAmyloid Precursor Protein (APP) cargoes with higher velocity in anterograde direction were observed compared with the retrograde one; meanwhile for Synaptophysin, a major population of stationary particles was found. Moreover, sorted data for axonal and dendritic transport description shown faster APP particles in axonal anterograde movement. Relying on the movement dynamics description, we decided to screen for protein‐protein interactions, using GFP‐trap and CoIP approaches followed by Mass Spectrometry analysis, which can shed light on possible partners involved in the transport regulation.ConclusionOur work describes an in vitro model for neuronal transport study and highlights the different behavior of proteins with various physiological functions. A complete view will elucidate details about transport regulation and will open a way to understand its role in neuropathological processes.

Novel borosilicate glass system: Na2B4O7-SiO2-MnO2: Synthesis, average electronics polarizability, optical basicity, and gamma-ray shielding features

A novel glass system with a chemical composition described by the formula 50SiO2– (48+x) Na2B4O7 – x MnO2 (0≤x≤2 mol %) was fabricated using a melt-quenching method. An XRD diffractometer procedure was applied to check the state of these glass samples. Obtaining the physical and optical values of the manganese borosilicate glass system can help develop solid-state devices and optical memory equipment. The energy gap shifting to higher energies may be due to the formation of bridging oxygens (BO). Urbach energies decrease in the range between 0.736 and 0.485 eV, with increasing the borax concentration between 48-50 mol %, respectively. The polarizability and optical basicity were investigated based on the experimental values of the refractive index for the fabricated glass samples. The polarizability and basicity were found to have the same trend as the refractive index. Monte Carlo N-particle transport code (MCNP-5) was applied to evaluate the gamma-shielding features for the investigated glass samples at gamma-photon energies between 0.248 and 1.406 MeV. The linear attenuation coefficient (LAC) was simulated based on the average track length of the gamma photons inside the fabricated glass samples. The highest LAC was achieved for the G5 glass sample, which has no MnO2 and changed between 0.330-0.153 cm−1 for photons with energy ranged between 0.248 and 1.406 MeV, respectively.

Quantitative capillary blood flow spatial analysis in skeletal muscle during sepsis

IntroductionTreatment of sepsis accounts for 23 billion healthcare dollars annually, and one in three hospitalized patients are diagnosed with sepsis. While current therapeutic strategies have been effective, sepsis‐induced mortality rates still remain greater than 10% and 40% with severe sepsis. Thus, new therapeutic approaches are needed.A defining characteristic of sepsis is that it induces hyperglycemia and an insulin resistant state. Skeletal muscle is one of the largest consumers of glucose in the body. Muscle glucose uptake can be controlled by: delivery of glucose through the vasculature, transport of glucose into the muscle, and muscle glucose metabolism. Hyperglycemia and insulin resistance may be due to a defect in one or more of these processes. Our lab and others have shown that inflammatory states cause alterations in vascular flow to the skeletal muscle. Further, changes in vascular flow have been shown to correlate with sepsis‐induced hyperglycemia and insulin resistance. Given that both sepsis and inflammation induce insulin resistance and are associated with impaired muscle blood flow, we hypothesize that protecting the endothelium from sepsis‐induced inflammation will prevent insulin resistance. We will test this hypothesis through the use of mice with a vascular specific knock down of NFκB. However, few tools exist too accurately and reproducibly measure changes in capillary flow with single‐capillary spatial resolution. To being testing the hypothesis we sought to develop and validate a method to measure capillary flow patterns to assess changes in microvascular flow and heterogeneity in the skeletal muscle.MethodIntravital microscopy was used to track fluorescent beads in mouse gastrocnemius muscle capillaries, and these data were used to build spatial capillary velocity profiles. Briefly, C57/BL6 mice with jugular vein catheters were anesthetized with isoflurane and the gastrocnemius was surgically exposed and positioned on a coverslip with warmed saline. Mice were then injected with 3 μm florescent beads and imaged at 111 frames per second. Resulting videos of binarized fluorescent beads were subjected to a positional tracking algorithm to yield a dataset of position and velocity data for tracked beads. This dataset was used to build capillary flow velocity maps for enhanced spatial visualization of flow data. Data analysis was conducted on both bead tracking data and capillary flow velocity maps using MATLAB. To assess whether the method could detect changes in capillary flow, mice were subjected to saline or lipopolysaccharide (2 mg/kg; LPS).ResultsThe average vessel track length was found to be 450 μm and the average vessel flow rate in the gastrocnemius was determined to be 1030 μm/second. To prevent tracking bead vessel selection bias, we averaged the spatial velocities of vessels, and determined the average spatial velocities of capillaries to be 970 μm/second. We calculated the sample size needed to determine a 10–50% change from baseline for all variables (Table 1). LPS decreased muscle capillary flow velocity and increased flow heterogeneity (Figure 1).ConclusionWe have developed a method to quantitate microvascular flow in the skeletal muscle of mice using flourescent beads. The average flow distribution and velocity of mice was consistent and stable. Additionally, when mice were challenged with LPS, we were able to detect a decrease in capillary flow and an increase in flow heterogeneity within the skeletal muscle.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Accelerated magnetic resonance diffusion tensor imaging of the median nerve using simultaneous multi-slice echo planar imaging with blipped CAIPIRINHA.

To investigate the feasibility of MR diffusion tensor imaging (DTI) of the median nerve using simultaneous multi-slice echo planar imaging (EPI) with blipped CAIPIRINHA. After federal ethics board approval, MR imaging of the median nerves of eight healthy volunteers (mean age, 29.4years; range, 25-32) was performed at 3T using a 16-channel hand/wrist coil. An EPI sequence (b-value, 1,000s/mm(2); 20 gradient directions) was acquired without acceleration as well as with twofold and threefold slice acceleration. Fractional anisotropy (FA), mean diffusivity (MD) and quality of nerve tractography (number of tracks, average track length, track homogeneity, anatomical accuracy) were compared between the acquisitions using multivariate ANOVA and the Kruskal-Wallis test. Acquisition time was 6:08min for standard DTI, 3:38min for twofold and 2:31min for threefold acceleration. No differences were found regarding FA (standard DTI: 0.620 ± 0.058; twofold acceleration: 0.642 ± 0.058; threefold acceleration: 0.644 ± 0.061; p ≥ 0.217) and MD (standard DTI: 1.076 ± 0.080mm(2)/s; twofold acceleration: 1.016 ± 0.123mm(2)/s; threefold acceleration: 0.979 ± 0.153mm(2)/s; p ≥ 0.074). Twofold acceleration yielded similar tractography quality compared to standard DTI (p > 0.05). With threefold acceleration, however, average track length and track homogeneity decreased (p = 0.004-0.021). Accelerated DTI of the median nerve is feasible. Twofold acceleration yields similar results to standard DTI. • Standard DTI of the median nerve is limited by its long acquisition time. • Simultaneous multi-slice acquisition is a new technique for accelerated DTI. • Accelerated DTI of the median nerve yields similar results to standard DTI.

Simultaneous Multislice Echo Planar Imaging With Blipped Controlled Aliasing in Parallel Imaging Results in Higher Acceleration: A Promising Technique for Accelerated Diffusion Tensor Imaging of Skeletal Muscle.

The aim of this study was to investigate the feasibility of accelerated diffusion tensor imaging (DTI) of skeletal muscle using echo planar imaging (EPI) applying simultaneous multislice excitation with a blipped controlled aliasing in parallel imaging results in higher acceleration unaliasing technique. After federal ethics board approval, the lower leg muscles of 8 healthy volunteers (mean [SD] age, 29.4 [2.9] years) were examined in a clinical 3-T magnetic resonance scanner using a 15-channel knee coil. The EPI was performed at a b value of 500 s/mm2 without slice acceleration (conventional DTI) as well as with 2-fold and 3-fold acceleration. Fractional anisotropy (FA) and mean diffusivity (MD) were measured in all 3 acquisitions. Fiber tracking performance was compared between the acquisitions regarding the number of tracks, average track length, and anatomical precision using multivariate analysis of variance and Mann-Whitney U tests. Acquisition time was 7:24 minutes for conventional DTI, 3:53 minutes for 2-fold acceleration, and 2:38 minutes for 3-fold acceleration. Overall FA and MD values ranged from 0.220 to 0.378 and 1.595 to 1.829 mm2/s, respectively. Two-fold acceleration yielded similar FA and MD values (P ≥ 0.901) and similar fiber tracking performance compared with conventional DTI. Three-fold acceleration resulted in comparable MD (P = 0.199) but higher FA values (P = 0.006) and significantly impaired fiber tracking in the soleus and tibialis anterior muscles (number of tracks, P < 0.001; anatomical precision, P ≤ 0.005). Simultaneous multislice EPI with blipped controlled aliasing in parallel imaging results in higher acceleration can remarkably reduce acquisition time in DTI of skeletal muscle with similar image quality and quantification accuracy of diffusion parameters. This may increase the clinical applicability of muscle anisotropy measurements.

Measurement of polystyrene beads suspended in a turbulent square channel flow: Spatial distributions of velocity and number density

Single view, inline digital holographic cinematography (1kHz) was used to track near neutrally buoyant, polystyrene beads in a turbulent water channel flow at bulk flow Reynolds number of 10,602. In-house developed algorithms, fine-tuned to tracking single and overlapping beads were developed. In total, 1616 beads were tracked using a nearest neighbor algorithm resulting in an average track length of 53ms. Overlapping beads were segmented using distance and watershed transforms. In most cases, beads’ in-focus positions were determined based on maximum rms of intensity gradients that outperformed other methods. Data processing and tracking was illustrated by a case study of four beads near the bottom channel wall. Bead diameters and in-plane positions/velocities were determined accurately. However, in the illumination direction, bead positions/velocities suffered from inherent in-focus inaccuracy. In agreement with available literature results, ascending beads lagged the mean streamwise water velocity while descending ones had similar velocities. Average streamwise bead velocities and number densities collapsed onto wall-normal-streamwise and spanwise–streamwise planes, indicated preferential segregation of ascending and descending beads up to a height of 100 wall units. Spanwise “lane” separation distances ranged between 150 and 200 wall units, larger but of the same order as the spanwise extent of coherent near-wall turbulence structures.

Abstract 2551: New understanding of cancer induction by ionizing radiation

Abstract Ionizing radiation is a unique carcinogen that provides an opportunity to vary the location of biological damage within a cell nucleus. For example, electron and x-ray beams deposit dose uniformly and randomly, while energetic heavy ions deposit dose in densely packed straight lines along the ion paths. Cancer yields for these 2 radiations vary as follows: upward curvature with dose rate sparing for random and linearity and no dose rate sparing for heavy ions. Dose rate sparing has long been assumed to be based on biological repair, but it has never been explained why dose responses should differ between these radiation or why repair should be ineffective for heavy ions. To understand this better, consider how the distribution of a typical molecular lesion, DNA double strand breaks (DSBs), varies with the type of radiation. For heavy ions at a specific energy, DSBs are expected to be lined up at random intervals along each track, their number being proportional to average track length in each nucleus, i.e. DSBs per nucleus are proportional to radiation dose (D). Increased charge on the heavy ion causes increased lineal energy transfer (L), i.e. DSBs are also proportional to L. Similarly for heavy ions fusions between DSBs would also be proportional to D and L. The comparable scenario for randomly deposited radiation differs in that the DSBs are distributed randomly with the nuclei. Their number remains proportional to radiation dose, but now fusions would exhibit proportionality to dose-squared as a direct result of the randomness of the DSBs. Moreover randomness eliminates simultaneity. Consequently DSBs can be eliminated before second ones occur close enough to fuse, which automatically gives rise to dose rate sparing. DSB fusion yields based on the above considerations would have the form Yfusions = CfLD + BfD2 with no dose rate sparing for the first term and positive dose rate sparing for the second term. If fusions are the initial lesion of radiation carcinogenesis, then Ycancer = CcaLD + BcaD2. Extensive cancer data in rat skin based on radiations with very different L values (56Fe (L = 150 keV/µ), 40Ar (L = 125 keV/ µ), 29Ne (L = 26 keV/ µ), 1H (L = 0.34 keV/ µ).) and doses are presented that confirm the existence of independent linear and dose-squared terms and that dose rate sparing only applies to the dose-squared term. The data support the proposition that DSB fusions could be the initial lesion of radiation carcinogenesis in the rat skin model. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2551. doi:1538-7445.AM2012-2551

Track Quality Based Multitarget Tracking Approach for Global Nearest-Neighbor Association

In multitarget tracking, in addition to the problem of measurement-to-track association, there are decision problems related to track confirmation and termination. In general, such decisions are taken based on the total number of measurement associations, length of no association sequence, and total lifetime of the track in question. For a better utilization of available information, confidence of the tracker on a particular track can be used. This quantity can be computed using the measurement-to-track association likelihoods corresponding to the particular track, target detection probability for the sensor-target geometry, and false alarm density. A track quality measure is proposed here for assignment-based global nearest neighbor (GNN) trackers. It can be noted that to compute track quality measure for assignment-based data association one needs to consider different detection events than those considered for computation of the track quality measures available in the literature, which are designed for probabilistic data association (PDA) based trackers. In addition to the proposed track quality measure, a multitarget tracker based on it is developed, which is particularly suitable in scenarios with temporarily undetectable targets. In this work, tracks are divided into three sets based on their quality and measurement association history: initial tracks, confirmed tracks, and unobservable tracks. Details of the update procedures of the three track sets are provided. The results show that discriminating tracks on the basis of their track quality can lead to longer track life while decreasing the average false track length.

A weather radar data processing module for storm analysis

A pre- and post-processing weather radar data module was developed in the Matlab suite of software with GIS data exchange abilities for storm event analysis. During pre-processing, each radar sweep is converted from spherical to Cartesian coordinates in the desired temporal and spatial resolution. The module's functionality in post processing includes radar data display, geo-referencing over GIS maps, data filtering with the Wiener filter and single or multiple sweep processing. The user can perform individual storm cell detection and tracking, resulting in the storm's average velocity and track length. The tested methods are modifications of the LoG (Laplacian of the Gaussian) blob detection method and a Brownian particle trajectory linking algorithm. Radar reflectivity factor (Z) data can be referenced over predefined rainfall (R) gauges in order to determine the radar Z–R equation parameters. The user can also produce spatially distributed precipitation estimates by using standard Z–R equations from the literature. The module's functionality is demonstrated using data from a rainfall event captured by the NSA Souda Bay C-Band radar during a storm in October 2006. Results show that the Rosenfeld Tropical Z–R equation is the one that gives a satisfactory description of the spatial and temporal precipitation distribution of the investigated event.

Climatology of Thunderstorms for North Dakota, 2002–06

Abstract Radar and surface thunderstorm data in North Dakota were investigated to obtain the climatology of thunderstorms in the state. A life cycle analysis for the individual storm cells between 2002 and 2006 was carried out, and it was found that June and July were the peak months, late afternoon to early morning was the peak time for thunderstorms, the average lifetime of storm cells was 23.6 min, the average gust wind speed was 16.5 m s−1, the average track length was 21.8 km, and the average movement speed was 16.4 m s−1. The average movement of storm cells varied with months, and the storms moved toward the north, the northeast, and the east. It was also demonstrated that there were 19–35 thunderstorm days each year in North Dakota and that, of these, 9–14 thunderstorm days each year were associated with high speed winds. Severe thunderstorms composed 1.7% of all the thunderstorms in 2002–06. The most intense thunderstorm in North Dakota between 2002 and 2006 was associated with a 5-yr-high wind speed of 31.4 m s−1. It was also found that the longer-lasting storms were the stronger storms.

TH‐D‐BRB‐04: Ion Chamber Dosimetry Modification under Strong Magnetic Field Conditions

Purpose: To examine the dose response of an ion chamber in an external magnetic field and to simulate the energy deposition using the Monte Carlo technique. Method and Materials: This work investigates the response of a 0.6cm3 Farmer chamber to an 11.17 mCi 137Cs source under the influence of a 1.5 T magnetic field on a GE MRI scanner. A wooden frame was designed that allowed varying field direction measurements while keeping the source to chamber axis distance constant. Monte Carlo simulations were conducted using FLUKA a particle physics transport package to score the energy deposition and the average electron track length inside the cavity. Results: Higher chamber current readings were obtained when a transverse (to chamber central axis) magnetic field was applied compared to zero B field conditions. Lower readings were obtained when a longitudinal field was present. A 4.8% increase was observed for the transverse field measurements and negative voltage polarity while a 3.5% decrease was measured for the longitudinal case. The positive polarity measurements showed a 3.7% increase and an 11.5% decrease in transverse and longitudinal fields vs. a 4.0% increase and a 6.0% decrease found through Monte Carlo simulations. The average track length increased by 11.0% and decreased by 6.8% in transverse and the longitudinal fields.Varying the electric field applied to the electrodes showed no significant changes in chamber response. Conclusion: The dose response of a Farmer chamber in an external magnetic field varies with the average charged particle trajectory length. The average trajectory depends on the B field magnitude and direction and on the energy spectrum of the primary photon beam. Thus an alignment with the B field direction would be essential. Smaller cavity chambers are expected to be affected less under B field conditions and should be investigated in the future.

Diffusion controlled reaction rate, survival probability, and molecular trajectory characteristics in the bulk, transition and Knudsen regime

Random walk simulation results are presented for the diffusion controlled reaction rate coefficient, molecular survival probability, average track length and relative collision frequency in the bulk, transition and Knudsen diffusion regime, in porous media formed by randomly oriented cylindrical fibers. The survival probability and mean survival distance are found to increase with the porosity in all diffusion regimes. The diffusion controlled reaction rate coefficient attains higher values at lower porosities, obeying an upper bound of the literature and approaching its value in the bulk regime. The values computed for all three parameters in the transition regime depend strongly on the Knudsen number, whereas in the Knudsen regime they are in line with analytical predictions based on the chord length distribution of the fiber structures. A harmonic average approximation based on Bosanquet's equation for the effective diffusivities is found to link successfully the values of the diffusion controlled reaction rate coefficient in the three diffusion regimes. The simulation results for the average molecular track length and relative collision frequency deviate in the biggest part of the transition regime from earlier analytical and numerical results obtained from long diffusion time random walks, in agreement with an analysis centered on the basic differences of molecular trajectories in diffusion controlled reaction systems from those involving molecular reflection from the pore surface.

Track measurements of fast particle streams in pulsed discharge explosive plasma

This paper reports results of track registration for fast particles from the hot spot sparked inside a metal target. CR-39 track detectors placed in the ion pinhole camera, a magnetic analyzer, and Thomson-type mass-spectrometer in order were used to obtain images of the hot spot and to determine spectra of the fast particles. Using track detectors in the pinhole camera, we have obtained specific split images. The “average etch rate ratio versus track length” locus for track sample groups is depicted by means of squared diameters asymptotic method. Our analysis shows the majority of tracks belong to hydrogen nuclei. The track loci for the detectors from the pinhole or analyzers turn out to be split into two parallel streaks that have been interpreted as a proton–deuteron doublet. Data obtained using the Thomson analyzer clearly demonstrate the equal numbers of protons and deuterons for some parallel parabola sections.