“硬件”与“虚拟”实验教学相关的思考

分别阐述硬件仪器设备实现实验教学和用虚拟电子实验平台实现实验教学的优缺点，并研究了它们之间的相互关系。力求科学处理它们之间的关系，达到全面培养学生实际动手能力之目的。

电子技术实验教学中的“虚”与“实”

论述了电子技术实验教学中“虚”与“实”的关系 ,在电子工作平台上利用虚拟仪器 (VI)技术进行实验教学 ,恰当确定虚拟技术在实践教学中的地位 。

Virtual Laboratory for Corporations: The Source of Policy

Many corporations are complaining that they cannot make decisions correctly. This article describes virtual laboratory (VL), an organization which can help managers make decision. The virtual laboratory based on Intranet uses many methods to draw policies for the corporation by analyzing business processes. It is a tool for learning organization too.

Study on Collision Between Two Ships Using Selected Parameters in Collision Simulation

In the present analysis, several parameters used in a numerical simulation are investigated in an integrated study to obtain their influence on the process and results of this simulation. The parameters studied are element formulation, friction coefficient, and material model. Numerical simulations using the non-linear finite element method are conducted to produce virtual experimental data for several collision scenarios. Pattern and size damages caused by collision in a real accident case are assumed as real experimental data, and these are used to validate the method. The element model study performed indicates that the Belytschko-Tsay element formulation should be recommended for use in virtual experiments. It is recommended that the real value of the friction coefficient for materials involved is applied in simulations. For the study of the material model, the application of materials with high yield strength is recommended for use in the side hull structure.

Effects of different poses and wind speeds on flow field of dish solar concentrator based on virtual wind tunnel experiment with constant wind

In order to improve structure performance of the dish solar concentrator,a three-dimensional model of dish solar concentrator was established based on the high-precision numerical algorithms.And a virtual wind tunnel experiment with constant wind is adopted to investigate the pressure distribution of the reflective surface,velocity distribution of the fluid domain for the dish solar concentrator in different poses and wind speeds distribution.Some results about wind pressure distribution before and after dish solar concentrator surface and wind load velocity distribution in the entire fluid domain had been obtained.In particular,it is necessary to point out that the stiffness at the center of the dish solar concentrator should be relatively raised.The results can provide a theoretical basis for the improvement of solar concentrator dish structure as well as the failure analysis of dish solar concentrator in engineering practice.

Microstructure modeling and virtual test of asphalt mixture based on three-dimensional discrete element method

The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete element method.A randomly generating algorithm was proposed to capture the three-dimensional irregular shape of coarse aggregate.And then,modeling algorithm and method for graded aggregates were built.Based on the combination of modeling of coarse aggregates,asphalt mastic and air voids,three-dimensional virtual sample of asphalt mixture was modeled by using PFC^(3D).Virtual tests for penetration test of aggregate and uniaxial creep test of asphalt mixture were built and conducted by using PFC^(3D).By comparison of the testing results between virtual tests and actual laboratory tests,the validity of the microstructure modeling and virtual test built in this study was verified.Additionally,compared with laboratory test,the virtual test is easier to conduct and has less variability.It is proved that microstructure modeling and virtual test based on three-dimensional discrete element method is a promising way to conduct research of asphalt mixture.

SATVPC:Secure-agent-based trustworthy virtual private cloud model in open computing environments

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.

The Design and Implementation of the Network Interactive Virtual Experiment Platform for Electronic Information Courses

Experimental teaching plays a crucial role in the trainings of students＇ abilities to analyze and solve problems. Therefore, it is very necessary to continuously carry out experiment teaching reform, improve experiment teaching methods and means, and comprehensively open laboratories so as to provide students with more opportunities of doing experiments. To improve the teaching effect of electronic information experimental courses, a network interactive virtual experimental platform is developed. This platform allows students to finish the construction of all kinds of circuit structures and test virtual instruments in a simulation environment, upload experimental data and also interactively communicate with teachers through the lnternet. The platform can be applied to the teaching activities of related electronic information experimental courses, and also can be used as an aid teaching method for theory teachers. Therefore, it possesses a very good interactivity, and makes up the disadvantages of the experimental teaching in hardware environment, so that a feasible solution is provided for the opening of laboratories.

Research on Simulation and Test of the Nonlinear Responses for the Hydraulic Shock Absorber

Basically on the multi-body system dynamics,the virtual prototype of the hydraulic shock absorber for the bench test is developed in the ADAMS environment.Dynamic behaviors of the absorber are studied by both computer simulation and real test.Numerical predictions of dynamic responses are produced by the established virtual prototype of the absorber and compared with experimental results.It has been shown from the comparison that the vibration behaviors of the prototype with hysteretic damping characteristics are considered to be more identical with the bench test results than those of the same prototype with piecewise linear damping properties are.The current virtual prototype of the shock absorber is correct and can be a developing terrace for the optimizing design of the absorber and matching capability of the whole car.

Real-time haptic model for soft tissue deformation in surgery simulation

The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment.In this paper,a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic rendering.During the modelling,the accumulation of relative displacements in every chain structure unit in each layer is equal to the deformation on the virtual object surface,and the resultant force of corresponding springs is equivalent to the external force.The layered rhombus-chain-connected model is convenient and fast to calculate,and can satisfy real-time requirement due to its simple nature.Simulation experiments in virtual human liver based on the proposed model are conducted,and the results demonstrate that our model provides stable and realistic haptic feeling in real time.Meanwhile,the display result is vivid.

Experimental study of Internet telerobotics based on virtual guides

For the virtual environment (VE) to control remote robots through Internet, this paper proposes an operational idea based on virtual guides (VGs). The VGs consist of three types, line VG, plane VG, and body VG, which can greatly enhance the safety and flexibility of the man-machine system. Through the analysis of several common cases, the idea of the VGs are first introduced and described. Second, detailed descriptions of the three VGs are given, and then a uniform representation of all VGs is given. Finally, a typical experiment is designed and implemented according to the modes of video feedback, video&VE feedback, and video&VE&VG feedback. Experimental results show that the operation based on VEs and VGs have significant advantages over that based on video feedback, and VGs can greatly improve the ability of the VE to control remote robots, thus obtaining high and efficient man-machine cooperation.

The Design and Implementation of Virtual Physics Experiment System based on VB Programming

This paper used the virtual reality modeling language （VRML） to establish the 3D virtual experiment instrument model, and by using the visual programming language VB to design and develop a interactive virtual realization experiment platform, the interface has friendly interface, stable operation, strong practicability like with the Windows style, is a kind of reform for the traditional physics experiment teaching mode. The system has practical use value, also has reference value for the reform and modernization of other experimental courses.

Solving the Perennial Problems of Inadequate Physical Laboratories in Africa Through the Use of Virtual Reality Technology and Tools

The major restriction for learning in science and engineering education in Africa is the absence of equipped laboratories. Where laboratory is available, there is the problem of obsolete and antiquated materials, which are seldom available for use. In most Universities in Africa, there is inadequate supply of laboratory space and laboratory materials. The laboratories only have the items of equipment that were provided when the universities were established, this has hampered learning. An alternative educational approach is required to address the aforementioned problems and provide a cost-effective solution for education as well as a valuable complementary or learning tool for university students. The alternative approach is the use of Virtual Reality （VR） technology to simulate virtual learning environments such as virtual reality laboratories. This is a one solution to inadequate physical laboratories in Africa.

How to Make Virtual Community More Active and Cohesive:From Brand and Perceived Protection Perspectives

With the increasing popularity of the Internet and mobile Internet, the Virtual Community （VC） is becoming an important medium for person-to-person communication. To realise the potential of the VC, it is neces- sary to cultivate within it good group cohesion and vitality. Using empirical and experimental research methods, this study explores the ef- fect of users＇ trust in the VC Platform （VCP） on group cohesion and vitality and how brand and perceived privacy security can affect us- ers＇ trust in the VC. The research results indi- cate that the brand of the VCP can directly af- fect users＇ trust in the VC, and can also influe- nce it indirectly through users＇ perceived pri- vacy protection and perceived security protec- tion. Further, this study also confu＇ms that the performance of the VC （group cohesion and vitality） is significantly affected by users＇ trust in the VC. The results of this study can provide theoretical guidance for internet companies to maintain and enhance the value of VCs.

Interactions between background matching and disruptive colouration： Experiments using human predators and virtual crabs

Interactions between disruptive colouration and the match between prey and background spot size were manipulated in two experiments that used time taken by human ＇predators＇ to find artificial prey （virtual crab morphs） against heterogeneous backgrounds as a measure of the their camouflage. Experiment 1, in which the spots and their placement imitated the arrangement on the crab Carcinus maenas, tested whether high and low contrast spots touching the body outline （disruptive ＇edge＇ morphs） made the artificial prey more difficult to detect than when the spots did not touch the outline （non-disruptive ＇inner＇ morphs） against three different backgrounds： ＇small＇, ＇middle＇ and ＇large＇ spot size. In Experiment 2, the range of spot sizes and their positions （＇edge＇ and ＇inner＇） on the crab morphs were varied to determine the most effective combination against the ＇mid- dle＇ background. Altogether, 640 volunteers participated in these computer trials, representing a high degree of independent replication. All patterned morphs were significantly harder to detect than plain morphs, indicating that possessing at least some degree of background matching can provide camouflage. Both experiments demonstrated that various morphs, though not having the same spot sizes as the background, had similar or better survivorship as those with matching spot sizes--indicating that opti- mal camouflage did not come from background matching alone. In Experiment 2, edge-disrupted morphs consistently took longer to find than their non-disruptive counterparts. The relative effects of edge disruption, contrast, and background/prey spot size are clearly context-dependent, highlighting the complexity of prey concealment [Current Zoology 61 （4）： 718-728, 2015].