An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Performance of missing transverse momentum reconstruction in proton-proton collisions at root s=13 TeV using the CMS detector

The performance of missing transverse momentum ((p) over right arrow (miss)(T)) reconstruction algorithms for the CMS experiment is presented, using proton-proton collisions at a center-of-mass energy of 13 TeV, collected at the CERN LHC in 2016. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The results include measurements of the scale and resolution of (p) over right arrow (miss)(T), and detailed studies of events identified with anomalous (p) over right arrow (miss)(T). The performance is presented of a (p) over right arrow (miss)(T) reconstruction algorithm that mitigates the effects of multiple proton-proton interactions, using the "pileup per particle identification" method. The performance is shown of an algorithm used to estimate the compatibility of the reconstructed (p) over right arrow (miss)(T) with the hypothesis that it originates from resolution effects.Peer reviewe

Real-time generation of smoothed-particle hydrodynamics-based special effects in character animation

In the previous works, the real-time fluid-character animation could hardly be achieved because of the intensive processing demand on the character's movement and fluid simulation. This paper presents an effective approach to the real-time generation of the fluid flow driven by the motion of a character in full 3D space, based on smoothed-particle hydrodynamics method. The novel method of conducting and constraining the fluid particles by the geometric properties of the character motion trajectory is introduced. Furthermore, the optimized algorithms of particle searching and rendering are proposed, by taking advantage of the graphics processing unit parallelization. Consequently, both simulation and rendering of the 3D liquid effects with realistic character interactions can be implemented by our framework and performed in real-time on a conventional PC. Copyright © 2013 John Wiley & Sons, Ltd.In the previous works, the real-time fluid-character animation could hardly be achieved because of the intensive processing demand on the character's movement and fluid simulation. This paper presents an effective approach to the real-time generation of the fluid flow driven by the motion of a character in full 3D space, based on smoothed-particle hydrodynamics method. The novel method of conducting and constraining the fluid particles by the geometric properties of the character motion trajectory is introduced. Furthermore, the optimized algorithms of particle searching and rendering are proposed, by taking advantage of the graphics processing unit parallelization. Consequently, both simulation and rendering of the 3D liquid effects with realistic character interactions can be implemented by our framework and performed in real-time on a conventional PC. Copyright © 2013 John Wiley & Sons, Ltd

Dynamic BFECC Characteristic Mapping method for fluid simulations

In this paper, we present a new numerical method for advection in fluid simulation. The method is built on the Characteristic Mapping method. Advection is solved via grid mapping function. The mapping function is maintained with higher order accuracy BFECC method and dynamically reset to identity mapping whenever an error criterion is met. Dealing with mapping function in such a way results in a more accurate mapping function and more details can be captured easily with this mapping function. Our error criterion also allows one to control the level of details of fluid simulation by simply adjusting one parameter. Details of implementation of our method are discussed and we present several techniques for improving its efficiency. Both quantitative and visual experiments were performed to test our method. The results show that our method brings significant improvement in accuracy and is efficient in capturing fluid details. © 2014 Springer-Verlag Berlin Heidelberg.In this paper, we present a new numerical method for advection in fluid simulation. The method is built on the Characteristic Mapping method. Advection is solved via grid mapping function. The mapping function is maintained with higher order accuracy BFECC method and dynamically reset to identity mapping whenever an error criterion is met. Dealing with mapping function in such a way results in a more accurate mapping function and more details can be captured easily with this mapping function. Our error criterion also allows one to control the level of details of fluid simulation by simply adjusting one parameter. Details of implementation of our method are discussed and we present several techniques for improving its efficiency. Both quantitative and visual experiments were performed to test our method. The results show that our method brings significant improvement in accuracy and is efficient in capturing fluid details. © 2014 Springer-Verlag Berlin Heidelberg

A comprehensive geometrical optics application for wave rendering

This paper presents a novel method to model wave effects in a ray tracer which attempts to account for the attenuation, scattering and absorption of light affected by participating media along rays. Inspired by diffraction shaders (DS), we propose an extension of this model to construct a new Bidirectional Reflectance Distribution Function (BRDF) to simultaneously take into consideration the phase and amplitude variation of light. The new method can simulate diffraction effects of a variety of materials, where we introduce the Fresnel factor and a microfacet scattering metric which affect the absorption and geometrical attenuation of photons. Incorporating Wigner Distribution Function (WDF), our method is further extended to model interference effects after multiple bounces by deferring the phase calculation. An acceleration algorithm is also implemented to real-time model diffraction effects of different apertures. We demonstrate the validity of our method by generating wave patterns for diverse scenes. © 2013 Elsevier Inc. All rights reserved.This paper presents a novel method to model wave effects in a ray tracer which attempts to account for the attenuation, scattering and absorption of light affected by participating media along rays. Inspired by diffraction shaders (DS), we propose an extension of this model to construct a new Bidirectional Reflectance Distribution Function (BRDF) to simultaneously take into consideration the phase and amplitude variation of light. The new method can simulate diffraction effects of a variety of materials, where we introduce the Fresnel factor and a microfacet scattering metric which affect the absorption and geometrical attenuation of photons. Incorporating Wigner Distribution Function (WDF), our method is further extended to model interference effects after multiple bounces by deferring the phase calculation. An acceleration algorithm is also implemented to real-time model diffraction effects of different apertures. We demonstrate the validity of our method by generating wave patterns for diverse scenes. © 2013 Elsevier Inc. All rights reserved

Real-time depth-of-field rendering using single-layer composition

In this paper, we propose a single-layer post-processing method for real-time depth-of-field rendering that uses single-layer composition. In the proposed method, blurring is achieved by gathering background pixels and scattering foreground pixels. Major artifacts in post-filtering techniques such as intensity leakage and blurring discontinuity are reduced by using two different blurring functions and the controllable parameter in the gathering process. The method can be entirely implemented in GPU parallelization to achieve the real-time performance required for virtual reality. The results of comparisons of our method with recent post-processing methods in terms of rendering quality and rendering performance indicate that our method generates realistic natural images and is also the fastest in terms of frames per second. Copyright © 2014 John Wiley & Sons, Ltd.In this paper, we propose a single-layer post-processing method for real-time depth-of-field rendering that uses single-layer composition. In the proposed method, blurring is achieved by gathering background pixels and scattering foreground pixels. Major artifacts in post-filtering techniques such as intensity leakage and blurring discontinuity are reduced by using two different blurring functions and the controllable parameter in the gathering process. The method can be entirely implemented in GPU parallelization to achieve the real-time performance required for virtual reality. The results of comparisons of our method with recent post-processing methods in terms of rendering quality and rendering performance indicate that our method generates realistic natural images and is also the fastest in terms of frames per second. Copyright © 2014 John Wiley & Sons, Ltd

Accurate gaze tracking from single camera using gabor corner detector

Most of the existing gaze tracking schemes with high accuracy and high speed depend on infra-red (IR) lights and multi-cameras, which leads to high complexity of apparatus and high cost. Besides, many proposed approaches hardly offer a full discussion and solution of eye blink issue. In this paper, we propose a novel gaze tracking scheme which is capable of tracking eye movements in high accuracy. Our scheme incorporates the eye corner information extracted using a novel eye corner detector. This detector is developed based on the Gabor Wavelet Transform and the Structure Tensor. Gabor Wavelet Transform decomposes an image in multi-scales and multi-orientations, thus is robust against lighting variation and tiny shift. We abstract the distribution statistics of the feature points in the eye region and re-express it as a connectivity graph. Based on such abstraction we propose a novel solution to the eye blink issue which obtains a high successful detection rate. After implementation, our scheme is proven to be accurate compared with the state of the art. Notably, only one web camera is employed in our scheme without any auxiliary light source or cameras.Most of the existing gaze tracking schemes with high accuracy and high speed depend on infra-red (IR) lights and multi-cameras, which leads to high complexity of apparatus and high cost. Besides, many proposed approaches hardly offer a full discussion and solution of eye blink issue. In this paper, we propose a novel gaze tracking scheme which is capable of tracking eye movements in high accuracy. Our scheme incorporates the eye corner information extracted using a novel eye corner detector. This detector is developed based on the Gabor Wavelet Transform and the Structure Tensor. Gabor Wavelet Transform decomposes an image in multi-scales and multi-orientations, thus is robust against lighting variation and tiny shift. We abstract the distribution statistics of the feature points in the eye region and re-express it as a connectivity graph. Based on such abstraction we propose a novel solution to the eye blink issue which obtains a high successful detection rate. After implementation, our scheme is proven to be accurate compared with the state of the art. Notably, only one web camera is employed in our scheme without any auxiliary light source or cameras

Research on knowledge service oriented expert management system

The distinctive characteristics of knowledge service oriented expert management system needs to have instant, on-demand service, accurate service, comprehensive services, and personalized service. In order to meet the requirements of the establishment of this system, this paper studied the construction of expert resources and expert retrieval services, and The crowdsourcing technology-based open expert body build, experts of different heterogeneous data sources access to information based expert body interaction semantics expert retrieval method. © (2014) Trans Tech Publications, Switzerland.The distinctive characteristics of knowledge service oriented expert management system needs to have instant, on-demand service, accurate service, comprehensive services, and personalized service. In order to meet the requirements of the establishment of this system, this paper studied the construction of expert resources and expert retrieval services, and The crowdsourcing technology-based open expert body build, experts of different heterogeneous data sources access to information based expert body interaction semantics expert retrieval method. © (2014) Trans Tech Publications, Switzerland