QoE Assessment of Will Transmission Using Vision and Haptics in Networked Virtual Environment

In this paper, we handle collaborative work in which two users move an object together to eliminate a target in a 3-D virtual space. In the work, the users transmit their wills about movement direction of the object to each other by only haptics and by haptics and vision (including with/ without drawing an arrow to indicate the direction of force applied to the object by the other user). We carry out QoE (Quality of Experience) assessment subjectively and objectively to investigate the influence of network delay on will transmission. As a result, we clarify the effects of vision on the transmissibility of haptic will transmission.

The Network Architecture and Protocols for Distributed Virtual Environment

In this paper, the properties of distributed virtual environment (DVE) and the requirements on computer networks is briefly reviewed. A multicast protocol, called sender initiated grouping multicast protocol for DVE (SIGMP), is proposed. This new multicast protocol is based on a novel concept, multicast group (MG), which divides all participants in a DVE system into groups, among which there is a multicast group trustee (MGT) node to manage the group. The protocol provides unreliable/reliable, totally ordered and multiple to multiple multicast transmission service for DVE systems without sacrificing the communication efficiency heavily. At the same time, reliable unicast and one to multiple multicast transmission services are also supported. The performance analysis of the new protocols is also presented. Based on SIGMP, a simple demonstration of DVE system is designed and implemented. This demo system is running on several SGI workstations connected by a FDDI and Ethernet network.

SFC placement and dynamic resource allocation based on VNF performance-resource function and service requirement in cloud-edge environment

With the continuous development of network func-tions virtualization(NFV)and software-defined networking(SDN)technologies and the explosive growth of network traffic,the requirement for computing resources in the network has risen sharply.Due to the high cost of edge computing resources,coordinating the cloud and edge computing resources to improve the utilization efficiency of edge computing resources is still a considerable challenge.In this paper,we focus on optimiz-ing the placement of network services in cloud-edge environ-ments to maximize the efficiency.It is first proved that,in cloud-edge environments,placing one service function chain(SFC)integrally in the cloud or at the edge can improve the utilization efficiency of edge resources.Then a virtual network function(VNF)performance-resource(P-R)function is proposed to repre-sent the relationship between the VNF instance computing per-formance and the allocated computing resource.To select the SFCs that are most suitable to deploy at the edge,a VNF place-ment and resource allocation model is built to configure each VNF with its particular P-R function.Moreover,a heuristic recur-sive algorithm is designed called the recursive algorithm for max edge throughput(RMET)to solve the model.Through simula-tions on two scenarios,it is verified that RMET can improve the utilization efficiency of edge computing resources.

Integration of Manufacturing Services into Virtual Environments over the Internet

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.

Machining process model based on virtual reality environment

Virtual manufacturing is fast becoming an affordable technology with wide-ranging applications in modern manufacturing. Its advantages over existing technology are primarily that users can visualize, feel involvement and interact with virtual representations of real world activities in real time. In this paper, a virtual cutting system is built which can simulate turning process, estimate tool wear and cutting force using artificial neural network etc. Using the simulated machining environment in virtual reality (VR), the user can practise and preview the operations for possible problems that might occur during implementation. This approach enables designers to evaluate and design feasible machining processes in a consistent manner as early as possible during the development process.

Influences of Network Delay on Quality of Experience for Soft Objects in Networked Real-Time Game with Haptic Sense

In this paper, we investigate the influences of network delay on QoE (Quality of Experience) such as the operability of haptic interface device and the fairness between players for soft objects in a networked real-time game subjectively and objectively. We handle a networked balloon bursting game in which two players burst balloons (i.e., soft objects) in a 3D virtual space by using haptic interface devices, and the players compete for the number of burst balloons. As a result, we find that the operability depends on the network delay from the local terminal to the other terminal, and the fairness is mainly dependent on the difference in network delay between the players’ terminals. We confirm that there exists a trade-off relationship between the operability and the fairness. We also see that the contribution of the fairness is larger than that of the operability to the comprehensive quality (i.e., the weighted sum of the operability and fairness). Assessment results further show that the output timing of terminals should be adjusted to the terminal which has the latest output timing to maintain the fairness when the difference in network delay between the terminals is large. In this way, the comprehensive quality at each terminal can be maintained as high as possible.

Net-VE系统中动态共享状态管理方法的研究

本文介绍了net VE系统中动态共享状态管理的三种方法及其优缺点,分析了如何使用分布式数据库来管理net VE中的共享状态,讨论了与分布式数据库的接口设计、接口要完成的主要功能、数据库中要存储的对象类型、共享状态的更新策略等。

用Virtual PC组建虚拟实验环境

提出了使用虚拟机的原因,介绍其优点、安装VirtualPC系统的需求和方法及用Ghost工具组建虚拟网络的过程。

The construction of personalized virtual landslide disaster environments based on knowledge graphs and deep neural networks

Virtual Landslide Disaster environments are important for multilevel simulation,analysis and decision-making about Landslide Disasters.However,in the existing related studies,complex disaster scene objects and relationships are not deeply analyzed,and the scene contents are fixed,which is not conducive to meeting multilevel visualization task requirements for diverse users.To resolve the above issues,a construction method for Personalized Virtual Landslide Disaster Environments Based on Knowledge Graphs and Deep Neural networks is proposed in this paper.The characteristics of relationships among users,scenes and data were first discussed in detail;then,a knowledge graph of virtual Landslide Disaster environments was established to clarify the complex relationships among disaster scene objects,and a Deep Neural network was introduced to mine the user history information and the relationships among object entities in the knowledge graph.Therefore,a personalized Landslide Disaster scene data recommendation mechanism was proposed.Finally,a prototype system was developed,and an experimental analysis was conducted.The experimental results show that the method can be used to recommend intelligently appropriate disaster information and scene data to diverse users.The recommendation accuracy stabilizes above 80%–a level able to effectively support The Construction of Personalized Virtual Landslide Disaster environments.

Virtual-reality-based digital twin of office spaces with social distance measurement feature

Background Social distancing is an effective way to reduce the spread of the SARS-CoV-2 virus.Many students and researchers have already attempted to use computer vision technology to automatically detect human beings in the field of view of a camera and help enforce social distancing.However,because of the present lockdown measures in several countries,the validation of computer vision systems using large-scale datasets is a challenge.Methods In this paper,a new method is proposed for generating customized datasets and validating deep-learning-based computer vision models using virtual reality(VR)technology.Using VR,we modeled a digital twin(DT)of an existing office space and used it to create a dataset of individuals in different postures,dresses,and locations.To test the proposed solution,we implemented a convolutional neural network(CNN)model for detecting people in a limited-sized dataset of real humans and a simulated dataset of humanoid figures.Results We detected the number of persons in both the real and synthetic datasets with more than 90%accuracy,and the actual and measured distances were significantly correlated(r=0.99).Finally,we used intermittent-layer-and heatmap-based data visualization techniques to explain the failure modes of a CNN.Conclusions A new application of DTs is proposed to enhance workplace safety by measuring the social distance between individuals.The use of our proposed pipeline along with a DT of the shared space for visualizing both environmental and human behavior aspects preserves the privacy of individuals and improves the latency of such monitoring systems because only the extracted information is streamed.

TVIDS: Trusted Virtual IDS With SGX

Network functions such as intrusion detection systems (IDS) have been increasingly deployed as virtual network functions or outsourced to cloud service providers so as to achieve the scalability and agility, and reducing equipment costs and operational cost. However, virtual intrusion detection systems (VIDS) face more serious security threats due to running in a shared and virtualized environment instead of proprietary devices. Cloud service providers or malicious tenants may illegally access and tamper with the policies, packet information, and internal processing states of intrusion detection systems, thereby violating the privacy and security of tenant’s networks. To address these challenges, we use Intel Software Guard Extensions (SGX) to build a Trusted Virtual Intrusion Detection System (TVIDS). For TVIDS, to prevent cloud service providers from accessing sensitive information about the users’ network, we build a trusted execution environment for security policy, packets processing, and internal state so that cloud service providers and other malicious tenants can’t access the protected code, policy, processing states, and packets information of the intrusion detection system. We implemented TVIDS on the basis of the Snort which is a famous open-source IDS and evaluated its results on real SGX hardware.The results show that our method can protect the security of the virtual IDS and brings acceptable performance overhead.

计算机网络实验课程教学改革研究

在计算机网络技术高速发展和大学生科学能力培养目标的新形势下,针对当前计算机网络实践教学存在的问题,提出“三位一体”的计算机网络实验课改革方案。从通信、协议和应用三个方面,构建计算机网络实验模块内容体系,综合运用现场实验、线上虚拟环境和虚拟仿真教学手段,充分激发学生的学习兴趣,有效发挥其学习专长,在教学设施投入受限的情况下,积极开展计算机网络实践教学。

网络安全中的威胁情报整合与VMware基础设施的主动安全措施

随着数字化时代到来,网络安全问题日益突出。文章旨在探讨网络安全中的威胁情报整合与VMware基础设施的主动安全措施。其中,威胁情报整合是一项关键活动,有助于组织更好地了解网络威胁,并加强防御措施,以提高对潜在攻击的应对能力。而在虚拟化环境中(如VMware基础设施),主动安全措施将成为维护系统完整性和安全性不可或缺的一部分。

分布式虚拟环境综述

在分布式虚拟环境中 ,位于不同物理位置的多个用户或多个虚拟环境通过网络相互联结 ,进行信息共享和交互 .该文结合作者的研究工作 ,从分布式虚拟环境的产生、需求和特征、模型和结构以及系统关键技术这几个方面对分布式虚拟环境的研究情况进行综述 。

基于虚拟化的网络创新实验环境研究

研究者针对未来网络创新研究而提出的各种创新性解决方案,需要在大规模真实网络实验环境中测试、验证.现有互联网无法支持基于后IP新型体系结构的创新实验,因此需要构建全面支持未来网络创新研究的实验环境.清华大学TUNIE平台,基于虚拟化技术,是拥有自主知识产权的未来网络创新实验环境.本文介绍网络创新实验环境的相关研究、关键技术,以及TUNIE设计目标、关键技术实现方案、平台部署情况等.目前,TUNIE平台已实现初步部署,应用于教学和科研中,并且承载一些网络创新实验.

虚拟计算环境中的虚拟网络

虚拟计算环境是近年来的学术研究热点,而虚拟网络是构成虚拟计算环境的核心技术。本文介绍了主流的虚拟网络构成原理和虚拟网络实现技术,分析了虚拟计算环境中虚拟网络的特点,总结并提出了虚拟网络的性能开销、QoS、自适应和安全性等开放性问题。

复杂工业过程仿真系统的虚拟环境

为提高仿真逼真度和仿真功能可扩充性 ,本文对当前复杂工业过程仿真系统的仿真环境所存在的缺点进行了分析 ,提出了建立复杂工业过程仿真系统的复制与虚拟环境相结合的设计思想 ,并通过电站网控仿真系统仿真环境的设计 ,讨论了这种设计思想在工程中的具体实现 ,并对实现上的一些技术细节进行了讨论。

虚拟声音会议环境中的应用共享

应用共享系统是一种ＣＳＣＷ 系统工具，它可以将单用户应用程序在多人的网络环境中协同地使用． 在应用共享系统中需要提供各用户间方便、直接的交互方式． 文中首先提出了一个应用共享系统的模型，介绍了公有区管理与发言权控制等关键技术． 其次讨论了基于Ａｇｅｎｔ的系统的软件结构，包括应用共享管理器的概念和应用协作Ａｇｅｎｔ的结构，进而给出了采用简化的ＨＲＴＦ模型的虚拟声音会议环境的设计方案． 最后描述了在虚拟声音会议环境中应用共享系统的实现方法． 通过虚拟声音会议。

网络教学平台的发展定位及服务设计

本文运用实证研究方法,对天津市高校用户进行了网络教学平台及其资源与服务问卷调研,在调研分析基础上,对网络教学平台的发展给予定位;从图书馆资源规划、图书馆服务设计、一体化虚拟学习环境设计三方面对网络教学平台的服务进行了设计。

空地战场作战可视化仿真系统研究

采用STAGE作为作战想定编辑器,MultiGenCreator和Vega作为视景仿真开发工具,在SGI350大型图形工作站上开发了空地战场作战可视化仿真系统。解决了作战想定的二维显示、三维地形建模、UNIX系统下的视景仿真软件开发以及经由实时网络接口与分布交互仿真系统的连接等关键技术。结果表明系统具有图像刷新快,实时性好和逼真度高等优点。