1,720,987 research outputs found
Real-Time Numerical Simulation for Accurate Soft Tissues Modeling during Haptic Interaction
Get PDFThe simulation of fabrics physics and its interaction with the human body has been largely studied in recent years to provide realistic-looking garments and wears specifically in the entertainment business. When the purpose of the simulation is to obtain scientific measures and detailed mechanical properties of the interaction, the underlying physical models should be enhanced to obtain better simulation accuracy increasing the modeling complexity and relaxing the simulation timing constraints to properly solve the set of equations under analysis. However, in the specific field of haptic interaction, the desiderata are to have both physical consistency and high frame rate to display stable and coherent stimuli as feedback to the user requiring a tradeoff between accuracy and real-time interaction. This work introduces a haptic system for the evaluation of the fabric hand of specific garments either existing or yet to be produced in a virtual reality simulation. The modeling is based on the co-rotational Finite Element approach that allows for large displacements but the small deformation of the elements. The proposed system can be beneficial for the fabrics industry both in the design phase or in the presentation phase, where a virtual fabric portfolio can be shown to customers around the world. Results exhibit the feasibility of high-frequency real-time simulation for haptic interaction with virtual garments employing realistic mechanical properties of the fabric materials
Fast approximations of activation functions in deep neural networks when using posit arithmetic
Get PDFWith increasing real-time constraints being put on the use of Deep Neural Networks (DNNs) by real-time scenarios, there is the need to review information representation. A very challenging path is to employ an encoding that allows a fast processing and hardware-friendly representation of information. Among the proposed alternatives to the IEEE 754 standard regarding floating point representation of real numbers, the recently introduced Posit format has been theoretically proven to be really promising in satisfying the mentioned requirements. However, with the absence of proper hardware support for this novel type, this evaluation can be conducted only through a software emulation. While waiting for the widespread availability of the Posit Processing Units (the equivalent of the Floating Point Unit (FPU)), we can already exploit the Posit representation and the currently available Arithmetic-Logic Unit (ALU) to speed up DNNs by manipulating the low-level bit string representations of Posits. As a first step, in this paper, we present new arithmetic properties of the Posit number system with a focus on the configuration with 0 exponent bits. In particular, we propose a new class of Posit operators called L1 operators, which consists of fast and approximated versions of existing arithmetic operations or functions (e.g., hyperbolic tangent (TANH) and extended linear unit (ELU)) only using integer arithmetic. These operators introduce very interesting properties and results: (i) faster evaluation than the exact counterpart with a negligible accuracy degradation; (ii) an efficient ALU emulation of a number of Posits operations; and (iii) the possibility to vectorize operations in Posits, using existing ALU vectorized operations (such as the scalable vector extension of ARM CPUs or advanced vector extensions on Intel CPUs). As a second step, we test the proposed activation function on Posit-based DNNs, showing how 16-bit down to 10-bit Posits represent an exact replacement for 32-bit floats while 8-bit Posits could be an interesting alternative to 32-bit floats since their performances are a bit lower but their high speed and low storage properties are very appealing (leading to a lower bandwidth demand and more cache-friendly code). Finally, we point out how small Posits (i.e., up to 14 bits long) are very interesting while PPUs become widespread, since Posit operations can be tabulated in a very efficient way (see details in the text)
Faster deep neural network image processing by using vectorized posit operations on a RISC-V processor
No full textReal-time processing of images and videos is becoming considerably crucial in modern applications of machine learning (ML) and deep neural networks. Having a faster and compressed floating point arithmetic can significantly increase the performance of such applications optimizing memory occupation and transfer of information. In this field, the novel posit number system is very promising. In this paper we exploit posit numbers to evaluate the performance of several machine learning algorithms in real-time image and video processing applications. Future steps will involve further hardware accelerations for native posit operations
Fast deep neural networks for image processing using posits and ARM scalable vector extension
No full textWith the advent of image processing and computer vision for automotive under real-time constraints, the need for fast and architecture-optimized arithmetic operations is crucial. Alternative and efficient representations for real numbers are starting to be explored, and among them, the recently introduced positTM number system is highly promising. Furthermore, with the implementation of the architecture-specific mathematical library thoroughly targeting single-instruction multiple-data (SIMD) engines, the acceleration provided to deep neural networks framework is increasing. In this paper, we present the implementation of some core image processing operations exploiting the posit arithmetic and the ARM scalable vector extension SIMD engine. Moreover, we present applications of real-time image processing to the autonomous driving scenario, presenting benchmarks on the tinyDNN deep neural network (DNN) framework
Experimental Results of Vectorized Posit-Based DNNs on a Real ARM SVE High Performance Computing Machine
No full textWith the pervasiveness of deep neural networks in scenarios that bring real-time requirements, there is the increasing need for optimized arithmetic on high performance architectures. In this paper we adopt two key visions: i) extensive use of vectorization to accelerate computation of deep neural network kernels; ii) adoption of the posit compressed arithmetic in order to reduce the memory transfers between the vector registers and the rest of the memory architecture. Finally, we present our first results on a real hardware implementation of the ARM Scalable Vector Extension
A Novel Posit-based Fast Approximation of ELU Activation Function for Deep Neural Networks
No full textNowadays, real-time applications are exploiting DNNs more and more for computer vision and image recognition tasks. Such kind of applications are posing strict constraints in terms of both fast and efficient information representation and processing. New formats for representing real numbers have been proposed and among them the Posit format appears to be very promising, providing means to implement fast approximated version of widely used activation functions in DNNs. Moreover, information processing performance are continuously improved thanks to advanced vectorized SIMD (single-instruction multiple-data) processor architectures and instructions like ARM SVE (Scalable Vector Extension). This paper explores both approaches (Posit-based implementation of activation functions and vectorized SIMD processor architectures) to obtain faster DNNs. The two proposed techniques are able to speed up both DNN training and inference steps
Preface (Editorial) [to Haptics: Science, Technology, and Applications, 11th International Conference, EuroHaptics 2018, Pisa, Italy, June 13-16, 2018, Proceedings, Part I]
No full textThe proceedings contain 36 papers. The special focus in this conference is on Science, Technology, and Applications. The topics include: Identification and evaluation of perceptual attributes for periodic whole-body and hand-arm vibration; influence of shape elements on performance during haptic rotation; effects of Chai3D texture rendering parameters on texture perception; effect of control movement scale on visual haptic interactions; tactile apparent motion through human-human physical touch; preliminary stiffness perception assessment for a tele-palpation haptic interface; passive probing perception: Effect of latency in visual-haptic feedback; perceived frequency of aperiodic vibrotactile stimuli depends on temporal encoding; haptic tracing of midair linear trajectories presented by ultrasound bessel beams; is cross-modal matching necessary? A bayesian analysis of individual reference cues; asymmetric cooling and heating perception; haptic scene analysis: Mechanical property separation despite parasitic dynamics; influence of scanning velocity on skin vibration for coarse texture; judged roughness as a function of groove frequency and groove width in 3D-printed gratings; using spatiotemporal modulation to draw tactile patterns in mid-air; discovering articulations by touch: A human study for robotics applications; a multimodal illusion of force improves control perception in above-surface gesture: Elastic zed-zoom; pseudohaptic feedback for teleoperated gripping interactions; a pilot study: Introduction of time-domain segment to intensity-based perception model of high-frequency vibration; haptic human-human interaction through a compliant connection does not improve motor learning in a force field; differences in beta oscillation of the middle frontal cortex with or without tactile stimulation in active touch task; relative sensation of wetness of different materials
A Fast Approximation of the Hyperbolic Tangent When Using Posit Numbers and Its Application to Deep Neural Networks
No full textDeep Neural Networks (DNNs) are being used in more and more fields. Among the others, automotive is a field where deep neural networks are being exploited the most. An important aspect to be considered is the real-time constraint that this kind of applications put on neural network architectures. This poses the need for fast and hardware-friendly information representation. The recently proposed Posit format has been proved to be extremely efficient as a low-bit replacement of traditional floats. Its format has already allowed to construct a fast approximation of the sigmoid function, an activation function frequently used in DNNs. In this paper we present a fast approximation of another activation function widely used in DNNs: the hyperbolic tangent. In the experiment, we show how the approximated hyperbolic function outperforms the approximated sigmoid counterpart. The implication is clear: the posit format shows itself to be again DNN friendly, with important outcomes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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