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Delivering high-definition (HD) videos to a large number of Internet users is a challenging research problem due to its heavy bandwidth consumption and inelastic quality-of-service (QoS) requirement. Different from the traditional content delivery networks and overlay peer-to-peer networks, crowdsourcing-based platforms, e.g., Thunder Crystal, deliver HD videos by renting agents' bandwidth and storage resources. Cash will be rewarded to agents based on agents' upload traffic. Online video providers, i.e., Tencent Video and YouKu, pay Thunder Crystal for its video distribution service. Therefore, a critical problem for Thunder Crystal is to evaluate the performance it can achieve, which determines Thunder Crystal's competitiveness and its bargaining power with online video providers. Although previously studied proportional video replication and random request scheduling strategy are implemented by Thunder Crystal, the system performance cannot be evaluated by simply using existing models, because of its novel business model. To address this problem, this paper proposes a theoretical framework that can analyze the performance for synchronized streaming, video-on-demand (VoD) streaming, and video downloading, which are all supported by Thunder Crystal. A differentiated bandwidth allocation is designed to boost Thunder Crystal's streaming performance by assigning downloading users more fluctuating bandwidth, which only slightly degrades downloading performance. Finally, simulation is conducted to validate the accuracy of our theoretical results. Refereed/Peer-reviewed

Content distribution, especially the distribution of video content, unavoidably consumes bandwidth resources heavily. Internet content providers invest heavily in purchasing content distribution network (CDN) services. By deploying tens of thousands of edge servers close to end users, CDN companies are able to distribute content efficiently and effectively, but at considerable cost. Thus, it is of great importance to develop a new system that distributes content at a lower cost but comparable service quality. In lieu of expensive CDN systems, we implement a crowdsourcing-based content distribution system, Thunder Crystal, by renting bandwidth for content upload/download and storage for content cache from agents. This is a large-scale system with tens of thousands of agents, whose resources significantly amplify Thunder Crystal’s content distribution capacity. The involved agents are either from ordinary Internet users or enterprises. Monetary rewards are paid to agents based on their upload traffic so as to motivate them to keep contributing resources. As far as we know, this is a novel system that has not been studied or implemented before. This article introduces the design principles and implementation details before presenting the measurement study. In summary, with the help of agent devices, Thunder Crystal is able to reduce the content distribution cost by one half and amplify the content distribution capacity by 11 to 15 times.

In a thermal simulation experiment of gold tubes of closed-system, calculating with the KINETICS and GOR-ISOTOPE KINETICS software, kinetic parameters of gas generation and methane carbon isotopic fractionation from Triassic—Jurassic hydrocarbon source rocks in the Kuqa depression of Tarim Basin are obtained. The activation energies of methane generated from Jurassic coal, Jurassic mudstone and Triassic mudstone in the Kuqa Depression are 197–268 kJ/mol, 180–260 kJ/mol and 214–289 kJ/mol, respectively, and their frequency factors are 5.265times1013s−1, 9.761times1011s−1 and 2.270times1014s−1. This reflects their differences of hydrocarbon generation behaviors. The kinetic parameters of methane carbon isotopic fractionation are also different in Jurassic coal, Jurassic mudstone and Triassic mudstone, whose average activation energies are 228 kJ/mol, 205 kJ/mol and 231 kJ/mol, respectively. Combined with the geological background, the origin of natural gas in the Yinan-2 gas pool is discussed, and an accumulation model of natural gas is thus established. The Yinan-2 gas is primarily derived from Jurassic coal-bearing source rocks in the Yangxia Sag. Main gas accumulation time is 5–0 Ma and the corresponding Ro is in the range from 1.25%–1.95%. The loss rate of natural gas is 25%–30%.

After the stage of higher tailoring, the candidate triangle pairs are still need to be further reduced to eliminate redundant tests in the stage of lower tailoring. This paper aims to propose a method to improve performance and efficiency in lower tailoring for self-collision detection of arm cloth simulation. Lower tailoring is a primitive level of cutting off redundant and non-colliding primitive pairs. Our method includes two stages. Firstly this paper eliminate redundant primitive pairs and remove non-intersecting primitive pairs by carrying out feature-based distribution and making intersection test of primitive bounding box. Secondly a non-coplanar filter is used to filter out non-coplanar primitive pairs within time step through non-coplanar test which further reduce candidate primitive pairs. Test results show that, our method can effectively remove redundant and non-colliding primitive pairs and has, to some extent, improved the efficiency for self-collision detection.

In the process of clothing simulation, visual authenticity of simulating effect has always been a criterion to measure the value of clothing simulation. In real life, wrinkle may occur to flexible clothing due to the interaction of forces, and are the major details of clothing fabrics that cannot be ignored. Hence, generating of wrinkles can intensify visual authenticity of clothing simulation and simulation of wrinkles has become an integral part for achieving authentic simulation of flexible clothing. This Paper has further studied on the methods for generating three-dimensional (3D) wrinkles. We proposed a new method for generating 3D wrinkles based on wrinkle baseline. The first step is to generate 3D wrinkle surface by convolution surface structuring method. Then generate finally clothing wrinkle by mapped the vertex in wrinkle area onto convolution surface. At last, adjusted section shape of the 3D wrinkles generated, so as to improve visual authenticity of clothing wrinkles.

This Paper presents an algorithm to optimize high-level culling for self-collision test of arm cloth grid. High-level culling is at the triangle level, to cut off non-colliding areas and triangular pairs and obtain all possibly colliding triangular pairs. Here, we processed basic high-level culling firstly by bounding box and continuous normal cone information. Then, we perform radiation angle test to cut off non-colliding triangular pairs through radiation angle test. At last, we cut off all neighbouring triangular pairs in the candidate triangular pairs based on Orphan set. Experimental results show that, the high-level culling optimization method here in the Paper can effectively cut off non-colliding triangular pairs and has greatly improved the efficiency for self-collision test.

Copyright 2015 ACM.Content distribution, especially the distribution of video content, unavoidably consumes bandwidth resource heavily. Internet content providers (ICP) spend lots of money to buy content distribution network (CDN) service. By deploying thousands of edge servers close to end users, CDN companies are able to distribute content efficiently. In lieu of traditional CDN systems, we implement a crowdsourcing-based content distribution system, Thunder Crystal, which utilizes agents' upload bandwidth to amplify the content distribution capacity. Agents are well motivated to contribute storage and upload bandwidth to the system by rebated cash. As far as we know, this is a novel system that has not been studied before. In this work, we will present its design principles first. Then, we study agent behavior and methods to evaluate system efficiency and user efficiency. We evaluate the system by simulations, and observe that agents are well motivated to keep online most of the time and amplify the content distribution capacity by 10∼20 times. Refereed/Peer-reviewed

Crowdsourcing-based video service systems, e.g., Thunder Crystal, are novel content distribution platforms composed by a large number of agent devices, acting like miniservers. Most agents are normal Internet users who would like to earn rewarded cash by uploading content through their devices. Compared with CDN, the bandwidth cost is much cheaper; while compared with Peer-To-Peer(P2P), the bandwidth supply is more stable. In this work, we create a stochastic model to analyze the live and VoD streaming performance in such crowdsourcingbased video service systems. Simulation is conducted to validate the accuracy of our analytical results. Refereed/Peer-reviewed