108 research outputs found

    Using Texture Synthesis for Non-Photorealistic Shading from Paint Samples

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    This paper presents several methods for shading meshes from scanned paint samples that represent dark to light transitions. Our techniques emphasize artistic control of brush stroke texture and color. We first demonstrate how the texture of the paint sample can be separated from its color gradient. We demonstrate three methods, two real-time and one off-line for producing rendered, shaded images from the texture samples. All three techniques use texture synthesis to generate additional paint samples. Finally, we develop metrics for evaluating how well each method achieves our goal in terms of texture similarity, shading correctness and temporal coherence

    Entrepreneurship as a potential driving force for the further development of rural areas

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    Entrepreneurial human capital and entrepreneurship are crucial elements for the further develop - ment of rural areas. In order to understand the role of rural enterprises it is essential to learn the characte - ristics of successful companies in local economies. The main aim of this paper is to demonstrate through the introduction of the activity, everyday practice and production procedure how non-agricultural and non-tourism enterprises can foster the development of rural and peripheral areas in the Visegrad countries. Nine local enter - prises of different size, profile and development pathway were examined in order to highlight main experiences and lessons being vital for and adaptable in other disadvantaged areas. The results and company descriptions provided in the article are based on in-depth interviews, online data collection and statistical analys

    Performance Improvement of an Indirect Solar Dryer with Single Axis Manual Tracking System and Angular Simulation of the Flat Plate Collector Reflectors

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    The need of food preservation cannot be over-emphasised. Crops need to be processed and preserved in times of their abundance to ensure for life and specie sustainability in times of scarcity. Flat plate collectors (FPCs) are often made fixed and the positions of reflectors used on them are not normally specified; in this paper, a report of an experimental test of an indirect solar dryer whose FPC is operated manually in a single axis to track the sun is presented. To avoid incurring extra cost on the existing design, the FPC was rather made to be operated manually instead of the automation process. Using the Engineering Equation Solver (EES) and the TRNSYS 16 softwares, the angular positions of reflectors placed east and west on the FPC were simulated for the first quarter months of the year of the experiment – this included the month of the test. This is to ascertain the best positions for the reflectors in other to achieve maximum insolation. For the month of the test, March, the angular positions of the reflectors placed east and west of the FPC were found to be 40° and 80° respectively relative to the horizontal plane. The performance of the solar dryer in terms of the percentage moisture loss, drying rate, collector efficiency and drying efficiency was evaluated when the FPC was fixed and when it was made to track the sun and the results obtained there from were compared. In comparison, it was found that the dryer tested by manually tracking the sun increased the total percentage moisture loss by 5.11%; the total drying rate by 2.10×10-5 kg/s; the average collector efficiency by 3.92% and the overall drying efficiency by 2.0% as compare to when the FPC was fixed, i.e. not tracking the sun. The indirect solar dryer with the ability to manually track the sun in a single axis using the meteorological conditions of Zaria, Nigeria was therefore found to have increased the performance of the system dryer as compare to when tracking of the sun was not done

    ToMRobot 2.0: real mobility mechanism in MANET testbed using mobile robot

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    This paper is a continuation of our previous paper under the same topic, ToMRobot 1.0. Our main goal of developing ToMRobot 2.0 is to improve the ToMRobot 1.0 that we developed earlier. ToMRobot was developed because we think mobile robot technology is more practical than other approaches as a real world mobility mechanism in MANET testbed. But to develop our own mobile robot at low cost and at the same time not complex is very challenging. The challenge is overcome through the use of easy-to-use components, self-built components using 3D printers and the use of mobile robot designs that have proven to be easily developed, cheap and effective. The use of the Robot Operating System (ROS) as the main robot software framework greatly helps to reduce the complexity of developing control system for mobile robot

    Mobile ad hoc network testbed using mobile robot technology

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    MANET (Mobile Ad Hoc Network) researchers have shown increased interest in using mobile robot technology for their testbed platforms. Thus, the main motivation of this paper is to review various robot-based MANET testbeds that have been developed in previously reported research. Additionally, suggestions to heighten mobility mechanisms by using mobile robots to be more practical, easy and inexpensive are also included in this paper, as we unveils ToMRobot, a low-cost MANET robot created from an ordinary remote control car that is capable of performing a real system MANET testbed with the addition of only a few low-cost electronic components. Despite greatly reduced costs, the ToMRobot does not sacrifice any of the necessary MANET basic structures and will still be easily customizable and upgradeable through the use of open hardware technology like Cubieboard2 and Arduino, as its robot controller. This paper will also include guidelines to enable technically limited MANET researchers to design and develop the ToMRobot. It is hoped that this paper achieves its two pronged objectives namely (i) to facilitate other MANET researchers by providing them with a source of reference that eases their decision making for selecting the best and most suitable MANET mobile robots for real mobility in their MANET testbeds (ii) to provide MANET researchers with a prospect of building their own MANET robots that can be applied in their own MANET testbed in the future

    4D and 5D phase-space tomography using slowing-down physics regularization

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    We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be istinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions

    Involvement of the Metabotropic Glutamate Receptor mGluR5 in NMDA Receptor-Dependent, Learning-Facilitated Long-Term Depression in CA1 Synapses

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    Learning-facilitated synaptic plasticity describes the ability of hippocampal synapses to respond with persistent synaptic plasticity to the coupling of weak afferent stimulation, which is subthreshold for the induction of plasticity, with a spatial learning experience. The metabotropic glutamate receptor subtype 5 (mGluR5) is critically involved in enabling the persistency of multiple forms of hippocampal synaptic plasticity. We compared the effects of pharmacological allosteric antagonism of mGluR5 in learning-facilitated plasticity with plasticity that had been induced solely by patterned afferent stimulation of the Schaffer collateral pathway to the CA1 stratum radiatum of adult freely behaving rats. Intracerebroventricular injection of the selective mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) had no effect on basal synaptic transmission but significantly prevented both long-term depression (LTD) elicited by electrical stimulation and LTD facilitated by novel object-place configuration learning. NMDA receptor antagonism also prevented learning-facilitated LTD. Habituation to the objects was prevented by MPEP application. Whereas reexposure to the object-place configuration (after 7 days) failed to facilitate LTD in control animals, those who had been treated previously with MPEP expressed LTD, suggesting that inhibition of learning contributed to the initial prevention of LTD. These data support a pivotal role for mGluR5 in both hippocampal LTD and the acquisition of object-place configurations

    Analysis of Sample Correlations for Monte Carlo Rendering

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    Modern physically based rendering techniques critically depend on approximating integrals of high dimensional functions representing radiant light energy. Monte Carlo based integrators are the choice for complex scenes and effects. These integrators work by sampling the integrand at sample point locations. The distribution of these sample points determines convergence rates and noise in the final renderings. The characteristics of such distributions can be uniquely represented in terms of correlations of sampling point locations. Hence, it is essential to study these correlations to understand and adapt sample distributions for low error in integral approximation. In this work, we aim at providing a comprehensive and accessible overview of the techniques developed over the last decades to analyze such correlations, relate them to error in integrators, and understand when and how to use existing sampling algorithms for effective rendering workflows.publishe

    Telomerase promoter mutations in cancer: an emerging molecular biomarker?

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    João Vinagre, Vasco Pinto and Ricardo Celestino contributed equally to the manuscript.Cell immortalization has been considered for a long time as a classic hallmark of cancer cells. Besides telomerase reactivation, such immortalization could be due to telomere maintenance through the “alternative mechanism of telomere lengthening” (ALT) but the mechanisms underlying both forms of reactivation remained elusive. Mutations in the coding region of telomerase gene are very rare in the cancer setting, despite being associated with some degenerative diseases. Recently, mutations in telomerase (TERT) gene promoter were found in sporadic and familial melanoma and subsequently in several cancer models, notably in gliomas, thyroid cancer and bladder cancer. The importance of these findings has been reinforced by the association of TERT mutations in some cancer types with tumour aggressiveness and patient survival. In the first part of this review, we summarize the data on the biology of telomeres and telomerase, available methodological approaches and non-neoplastic diseases associated with telomere dysfunction. In the second part, we review the information on telomerase expression and genetic alterations in the most relevant types of cancer (skin, thyroid, bladder and central nervous system) on record, and discuss the value of telomerase as a new biomarker with impact on the prognosis and survival of the patients and as a putative therapeutic target
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