Simulating the softness property of object is quite a challenge in virtual reality system. A novel softness display system was developed based on the principle of deformable length of elastic element control （DLEEC）...Simulating the softness property of object is quite a challenge in virtual reality system. A novel softness display system was developed based on the principle of deformable length of elastic element control （DLEEC）. In the system, the equivalent stiffness of the device is adjustable, and is inversely proportional to the third power of the deformable length of elastic beam. PD position control is employed to guarantee the accurate softness display. The softness of the virtual objects in large scale can be felt with the softness display device. Compared with other haptic devices, the device is passive and exert the react force only when the operator ＂actively touch＂ the virtual objects. The stability of the softness display system was analyzed. It was theoretical proved that the system satisfied the criteria of wide impedance range ＂Z-width＂, and the performance was superior to an active system. The experimental results were presented.展开更多
Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main mo...Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main modules——data sources, 3D simulation terrain database, 3D simulation model database, 3D simulation implementation and application system. Then the key technoiogies of constructing Virtual Huanghe River System were discussed in detail： 1） OpenGL technology, the 3D graphics developing instrument, was employed in Virtual Huanghe River System to realize the function of dynamic real-time navigation. 2） MO and OpenGL technologies were used to make the mutual response between 3D scene and 2D electronic map available, which made use of the advantages of both 3D scene and 2D electronic map, with the macroscopic view, integrality and conciseness of 2D electronic map combined with the locality, reality and visualization of 3D scene. At the same time the disadvantages of abstract and ambiguity of 2D electronic map and the direction losing of virtual navigation in 3D scene were overcome.展开更多
For Virtual Reality(VR) to be truly immersive, it needs convincing sound to match. Due to the diversity of individual's anthropometric measurements, the individualized customization technology is needed to get con...For Virtual Reality(VR) to be truly immersive, it needs convincing sound to match. Due to the diversity of individual's anthropometric measurements, the individualized customization technology is needed to get convincing sound. In this paper, we proposed a simple and effective method for modeling relationships between anthropometric measurements and Head-related Impulse Response(HRIR). Considering the relationship between anthropometric measurements and different HRIR parts is complicated, we divided the HRIRs into small segments and carried out regression analysis between anthropometric measurements and each segment to establish relationship model. The results of objective simulation and subjective test indicate that the model can generate individualize HRIRs from a series of anthropometric measurements. With the individualized HRIRs, we can get more accurate acoustic localization sense than using non-individualized HRIRs.展开更多
Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and soft...Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and software resources sufficiently,but also bring a series of security,reliability and credibility problems.To solve these problems,a novel secure-agent-based trustworthy virtual private cloud model named SATVPC was proposed for the integrated and open cloud computing environment.Through the introduction of secure-agent technology,SATVPC provides an independent,safe and trustworthy computing virtual private platform for multi-tenant systems.In order to meet the needs of the credibility of SATVPC and mandate the trust relationship between each task execution agent and task executor node suitable for their security policies,a new dynamic composite credibility evaluation mechanism was presented,including the credit index computing algorithm and the credibility differentiation strategy.The experimental system shows that SATVPC and the credibility evaluation mechanism can ensure the security of open computing environments with feasibility.Experimental results and performance analysis also show that the credit indexes computing algorithm can evaluate the credibilities of task execution agents and task executor nodes quantitatively,correctly and operationally.展开更多
with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this...with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation(DIV) framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine's architecture stack.DIV introduces a trusted third party(TTP) to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.展开更多
A virtual reality model was created in order to help in the maintenance of exterior closures and interior finishes of walls in a building. It allows the visual and interactive transmission of information related to th...A virtual reality model was created in order to help in the maintenance of exterior closures and interior finishes of walls in a building. It allows the visual and interactive transmission of information related to the physical behavior of the elements, defined as a function of the time variable. To this end, the basic knowledge of material most often used in walls, anomaly surveillance, techniques of rehabilitation, and inspection planning were studied. This information was included in a database that supports the periodic inspection needed in a program of preventive maintenance. The results are obtained interactively and visualized in the virtual environment itself. This work brings an innovative contribution to the field of maintenance supported by emergent technology.展开更多
This paper presents the Bayes estimation and empirical Bayes estimation of causal effects in a counterfactual model. It also gives three kinds of prior distribution of the assumptions of replaceability. The experiment...This paper presents the Bayes estimation and empirical Bayes estimation of causal effects in a counterfactual model. It also gives three kinds of prior distribution of the assumptions of replaceability. The experiment shows that empirical Bayes estimation is better than other estimations when not knowing which assumption is true.展开更多
基金Supported by the National Basic Research and Development Program （No. 2002CB312102） and the National Natural Science Foundation of China （No. 60643007, 60475034）.
文摘Simulating the softness property of object is quite a challenge in virtual reality system. A novel softness display system was developed based on the principle of deformable length of elastic element control （DLEEC）. In the system, the equivalent stiffness of the device is adjustable, and is inversely proportional to the third power of the deformable length of elastic beam. PD position control is employed to guarantee the accurate softness display. The softness of the virtual objects in large scale can be felt with the softness display device. Compared with other haptic devices, the device is passive and exert the react force only when the operator ＂actively touch＂ the virtual objects. The stability of the softness display system was analyzed. It was theoretical proved that the system satisfied the criteria of wide impedance range ＂Z-width＂, and the performance was superior to an active system. The experimental results were presented.
基金Under the auspices of the Science Data Sharing Pilot Project of Ministry of Science and Technology of China (No. 2003DEA2C010), Natural Science Fund of Henan University on Virtual City Construction Method (No. 04YBRW026)
文摘Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main modules——data sources, 3D simulation terrain database, 3D simulation model database, 3D simulation implementation and application system. Then the key technoiogies of constructing Virtual Huanghe River System were discussed in detail： 1） OpenGL technology, the 3D graphics developing instrument, was employed in Virtual Huanghe River System to realize the function of dynamic real-time navigation. 2） MO and OpenGL technologies were used to make the mutual response between 3D scene and 2D electronic map available, which made use of the advantages of both 3D scene and 2D electronic map, with the macroscopic view, integrality and conciseness of 2D electronic map combined with the locality, reality and visualization of 3D scene. At the same time the disadvantages of abstract and ambiguity of 2D electronic map and the direction losing of virtual navigation in 3D scene were overcome.
基金supported by the National Key R&D Program of China(No.2017YFB1002803)the National Nature Science Foundation of China(No.61671335,No.U1736206,No.61662010)the Hubei Province Technological Innovation Major Project(No.2016AAA015)
文摘For Virtual Reality(VR) to be truly immersive, it needs convincing sound to match. Due to the diversity of individual's anthropometric measurements, the individualized customization technology is needed to get convincing sound. In this paper, we proposed a simple and effective method for modeling relationships between anthropometric measurements and Head-related Impulse Response(HRIR). Considering the relationship between anthropometric measurements and different HRIR parts is complicated, we divided the HRIRs into small segments and carried out regression analysis between anthropometric measurements and each segment to establish relationship model. The results of objective simulation and subjective test indicate that the model can generate individualize HRIRs from a series of anthropometric measurements. With the individualized HRIRs, we can get more accurate acoustic localization sense than using non-individualized HRIRs.
基金Projects(61202004,61272084)supported by the National Natural Science Foundation of ChinaProjects(2011M500095,2012T50514)supported by the China Postdoctoral Science Foundation+2 种基金Projects(BK2011754,BK2009426)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(12KJB520007)supported by the Natural Science Fund of Higher Education of Jiangsu Province,ChinaProject(yx002001)supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Private clouds and public clouds are turning mutually into the open integrated cloud computing environment,which can aggregate and utilize WAN and LAN networks computing,storage,information and other hardware and software resources sufficiently,but also bring a series of security,reliability and credibility problems.To solve these problems,a novel secure-agent-based trustworthy virtual private cloud model named SATVPC was proposed for the integrated and open cloud computing environment.Through the introduction of secure-agent technology,SATVPC provides an independent,safe and trustworthy computing virtual private platform for multi-tenant systems.In order to meet the needs of the credibility of SATVPC and mandate the trust relationship between each task execution agent and task executor node suitable for their security policies,a new dynamic composite credibility evaluation mechanism was presented,including the credit index computing algorithm and the credibility differentiation strategy.The experimental system shows that SATVPC and the credibility evaluation mechanism can ensure the security of open computing environments with feasibility.Experimental results and performance analysis also show that the credit indexes computing algorithm can evaluate the credibilities of task execution agents and task executor nodes quantitatively,correctly and operationally.
基金Supported by the National Natural Science Foundation of China under Grant No. 61370068
文摘with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation(DIV) framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine's architecture stack.DIV introduces a trusted third party(TTP) to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.
文摘A virtual reality model was created in order to help in the maintenance of exterior closures and interior finishes of walls in a building. It allows the visual and interactive transmission of information related to the physical behavior of the elements, defined as a function of the time variable. To this end, the basic knowledge of material most often used in walls, anomaly surveillance, techniques of rehabilitation, and inspection planning were studied. This information was included in a database that supports the periodic inspection needed in a program of preventive maintenance. The results are obtained interactively and visualized in the virtual environment itself. This work brings an innovative contribution to the field of maintenance supported by emergent technology.
文摘This paper presents the Bayes estimation and empirical Bayes estimation of causal effects in a counterfactual model. It also gives three kinds of prior distribution of the assumptions of replaceability. The experiment shows that empirical Bayes estimation is better than other estimations when not knowing which assumption is true.
