458 research outputs found

    Proton therapy Monte Carlo SRNA-VOX code

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    The most powerful feature of the Monte Carlo method is the possibility of simulating all individual particle interactions in three dimensions and performing numerical experiments with a preset error. These facts were the motivation behind the development of a general-purpose Monte Carlo SRNA program for proton transport simulation in technical systems described by standard geometrical forms (plane, sphere, cone, cylinder, cube). Some of the possible applications of the SRNA program are: (a) a general code for proton transport modeling, (b) design of accelerator-driven systems, (c) simulation of proton scattering and degrading shapes and composition, (d) research on proton detectors; and (e) radiation protection at accelerator installations. This wide range of possible applications of the program demands the development of various versions of SRNA-VOX codes for proton transport modeling in voxelized geometries and has, finally, resulted in the ISTAR package for the calculation of deposited energy distribution in patients on the basis of CT data in radiotherapy. All of the said codes are capable of using 3-D proton sources with an arbitrary energy spectrum in an interval of 100 keV to 250 MeV

    Recognition of one class of quadrics from 3D point clouds

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    Within cyber physical production systems 3D vision as a source of information from real-world provides enormous possibilities. While the hardware of contemporary 3D scanners is characterized by high speed along with high resolution and accuracy, there is a lack of real-time online data processing algorithms that would give certain elements of intelligence to the sensory system. Critical elements of data processing software are efficient, real-time applicable methods for fully automatic recognition of high level geometric primitives from point cloud (surface segmentation and fitting). This paper presents a method for recognition of one class of quadrics from 3D point clouds, in particular for recognition of cylinders, elliptical cylinders and ellipsoids. The method is based on the properties of scatter matrix during direct least squares fitting of ellipsoids. Presented recognition procedure can be employed for segmentation of regions with G1 or higher continuity, and this is its comparative advantage to similar methods. The applicability of the method is illustrated and experimentally verified using two case studies. First case study refers to a synthesized, and the second to a real-world scanned point cloud

    Recognition of one class of quadrics from 3D point clouds

    Get PDF
    Within cyber physical production systems 3D vision as a source of information from real-world provides enormous possibilities. While the hardware of contemporary 3D scanners is characterized by high speed along with high resolution and accuracy, there is a lack of real-time online data processing algorithms that would give certain elements of intelligence to the sensory system. Critical elements of data processing software are efficient, real-time applicable methods for fully automatic recognition of high level geometric primitives from point cloud (surface segmentation and fitting). This paper presents a method for recognition of one class of quadrics from 3D point clouds, in particular for recognition of cylinders, elliptical cylinders and ellipsoids. The method is based on the properties of scatter matrix during direct least squares fitting of ellipsoids. Presented recognition procedure can be employed for segmentation of regions with G1 or higher continuity, and this is its comparative advantage to similar methods. The applicability of the method is illustrated and experimentally verified using two case studies. First case study refers to a synthesized, and the second to a real-world scanned point cloud

    The wild sunflowers collection in Novi Sad

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    Lowered genetic variability in the cultivated sunflower and use of interspecies hybridization in sunflower breeding were the main reasons to establish the wild species collection. Wild species were collected during collecting trips performed jointly by researchers from Novi Sad and Fargo from 1980 to 1991. A total of 917 accessions were gathered. Different numbers of species (1-37) and populations (52-384) were gathered in each trip and wild sunflower habitats were inspected in 6-21 US federal states. Presently there are 21 perennial and 7 annual species in the collection, represented by 447 accessions. The perennial species are grown in quarantine fields (311 accessions) and kept in temporary seed storage at +4° (163 accessions). Annual species are sawn each year and 136 accessions are kept in temporary seed storage. Seed reserves vary from a few seeds to several thousand per accession and all of them were produced in the period between 1998 and 2004. Several problems were encountered in the course of the establishment maintenance and utilization of the collection: 1. Occasional errors in species determination during collection trips were caused by the presence of natural hybrids, heterogeneity of natural populations and differences in ploidy within the same species; 2. The local continental climate caused loss in material due to winterkill and inability of some species to complete the vegetative cycle; 3. Perennial species were difficult to grow because of low seed viability; 4. Low self-fertility or complete selfsterility precluded seed production and renewal of seed reserves; 5. Wild species were difficult to utilize as a source of desirable genes because of their cross incompatibility with cultivated sunflower. The collection of wild sunflower species has mostly been used for development of disease resistant or tolerant genotypes, new cms and Rf genes and for breeding of special-purpose hybrids

    Anisotropy of Thermal Conductivity and Possible Signature of the Fulde-Ferrell-Larkin-Ovchinnikov state in CeCoIn_5

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    We have measured the thermal conductivity of the heavy-fermion superconductor CeCoIn_5 in the vicinity of the upper critical field, with the magnetic field perpendicular to the c axis. Thermal conductivity displays a discontinuous jump at the superconducting phase boundary below critical temperature T_0 ~ 1 K, indicating a change from a second to first order transition and confirming the recent results of specific heat measurements on CeCoIn_5. In addition, the thermal conductivity data as a function of field display a kink at a field H_k below the superconducting critical field, which closely coincides with the recently discovered anomaly in specific heat, tentatively identified with the appearance of the spatially inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state. Our results indicate that the thermal conductivity is enhanced within the FFLO state, and call for further theoretical investigations of the order parameter's real space structure (and, in particular, the structure of vortices) and of the thermal transport within the inhomogeneous FFLO state.Comment: 19 pages, 6 figures, submitted to Prhys. Rev.

    Dynamic adsorption characteristics of thin layered activated charcoal materials used in chemical protective overgarments

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    The efficiency of a thin layered activated charcoal material used in chemical protective overgarments has been evaluated. The study has been conducted with the aim to obtain protective materials with best characteristics considering resistance to benzene effect under dynamic conditions and to create a new filtration protection device. In order to evaluate dynamic adsorption characteristics of thin layered sorption materials, sophisticated dynamic gas chromatography method is used. The curves of benzene penetration are determined for sandwich materials, and sorption layers used in filtrating protective clothing shows that thin layered carbon sorption materials (type M00) have good protective properties as compared to other similar materials. The findings will help to create conditions for developing a functional model for producing a new protective overgarment in the near future

    Cross-Lingual Neural Network Speech Synthesis Based on Multiple Embeddings

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    The paper presents a novel architecture and method for speech synthesis in multiple languages, in voices of multiple speakers and in multiple speaking styles, even in cases when speech from a particular speaker in the target language was not present in the training data. The method is based on the application of neural network embedding to combinations of speaker and style IDs, but also to phones in particular phonetic contexts, without any prior linguistic knowledge on their phonetic properties. This enables the network not only to efficiently capture similarities and differences between speakers and speaking styles, but to establish appropriate relationships between phones belonging to different languages, and ultimately to produce synthetic speech in the voice of a certain speaker in a language that he/she has never spoken. The validity of the proposed approach has been confirmed through experiments with models trained on speech corpora of American English and Mexican Spanish. It has also been shown that the proposed approach supports the use of neural vocoders, i.e. that they are able to produce synthesized speech of good quality even in languages that they were not trained on
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