Applied Mechanics and Materials Vols. 284-287

Abstract: In this paper, we are proposing a web-based virtual collaboration system for e-learning system. We propose new multimedia presentation and recordable virtual collaboration which supports synchronized multimedia presentation using Synchronous Multimedia Integration Language (SMIL). It allows synchronization of the contents of a PowerPoint presentation file and a video file so that the presentation shows slides and video on the same topic at any given time. The resulting SMIL file is used to provide multimedia presentation for image intensive discussion. Participants can use text along with associated symbols during the discussion over the presented power point slides. The symbols such as arrows or polygons have x-y coordinates within the slides to represent associated participants’ questions and answers. Those can be set or removed dynamically to represent areas of questions in slides using so called layered architecture that separates slide layer from annotation layer. Those annotations can be easily hidden for training purposes. XML files are used to record participants’ questions and answers along with the associated elements such as arrows and polygons over some particular images.

Abstract: This article introduces cloud model to estimation of quality of service for voice communication network. It presents ideas of design, implementation procedure, carries out analysis of related key techniques, puts forward an improved backward cloud generator algorithm and conducts validating experiments. The results show that this model can handle the fuzziness and randomness of voice communication network well, adjust to uncertainty that hyper-entropy brings, reduce the impact of human factors, estimate grade of quality of service for voice communication network correctly and provide strong fundaments for further proper measures. It preserves the inherent uncertainty in the process of estimating at most and improves reliability of estimating results.

Abstract: This work lies on the framework of an interactive virtual environment for nanomanipulation. The model for the simulation of a manipulated nanoparticle dynamics in the virtual environment is constructed from the computed molecular dynamics. According to the operation by single-tip scanning probe microscope(SPM) for the nanomanipulation, the molecular forces are calculated based on the Lennard-Jones force-field such that the motion of the manipulated nanoparticles can be rendered for real-time virtual reality applications. Moreover, by coupling the CAD softwares to virtual reality (VR) techniques, the interactive virtual environment is developed for intuitive nanomanipulation visualization. Using the simulated nanomanipulation environment in VR, the operator can characterize and control the behavior of nanoparticles under the assumed SPM through physical simulation and 3D visualization.

Abstract: The design of mechanical structural parts is now predominantly a digital process. As an important element of the virtual design cycle, these parts must be tested for their structural integrity using finite element analysis (FEA) software. However, the interface between CAD and FEA is imperfect. The process of preparing CAD models for FEA consumes a great deal of the stress analyst’s time. Existing “automatic” CAD to FEA translators tend to treat all part features as “solid”; this leads to longer computation times and less accurate results for features that can be better characterized as “thin” or “long.” In addition, many features of CAD parts (e.g. fillets and chamfers) are important for their size and shape in the manufactured product, but have relatively little impact on the strength of the part and needlessly complicate the stress analysis—these features are usually removed by the analyst prior to FEA; they may need to be evaluated with additional analyses to test if it is safe to remove them. The Automatic CAD-FEA Interface Project (ACFI), is developing algorithms to make the translation from CAD to FEA seamless and automatic; these algorithms are based on mathematical theory and the principles of theoretical mechanics. This paper presents the latest ACFI advances for (i) automatically evaluating and reworking three dimensional CAD part geometries to prepare them for finite element meshing, (ii) exporting the revised geometries to a preprocessor, and (iii) identifying element type to be associated with each feature geometry. The algorithms used in this work approximate the medial axis transform (MAT) of the CAD part, a “power shape” that represents the three-dimensional solid part. This part can then be evaluated for its geometric properties. This approach has been shown to be a robust method for shape interrogation of three dimensional geometries.

Abstract: Abstract. Large amount of video data is stored and distributed in wide variety of application. Due to the fast video material increases, manage and query of video become more and more important. In this paper, we address a temporal signature representation and similarity model to retrieval the similar video within database by video query. Experimental results on real date are presented. The experimental results show that the statistical approach permits accurate query of video clip, in particular, the performance of the approach was found extremely satisfactory with determine all similar video in database.

Abstract: Advanced multimedia computing technology is capable of providing user-oriented services for the user and the environment through context-awareness. This study seeks to provide seamless video delivery service with the focus on the user’s mobility patterns during a multimedia streaming service session. Mobility supporting technology which ensures the provision of seamless services can be classified into host mobility and user mobility. The former corresponds to host-level handoff while the latter refers to user-level handoff. In host-level handoff, the factors that directly affect the quality of video consumption are total distance between hosts, the distance for streaming resuming while user is in mobility mode as well as the screen size of the end host. The relationship among these parameters is analyzed by carrying out a user subjective assessment and an appropriate video quality model was developed, accordingly. The proposed quality model supporting seamless-mobility has a high correlation to the assessed quality and enables an adequate seamless mobility for multimedia service delivery.

Abstract: Cylindrical panoramic view is a 360-degrees horizontal representation of a certain scene. The user can navigate interactively through the scene and change their view angles. Basically, panoramic views are often high-resolution, high-definition and consume a significant amount of bandwidth for transmission through Internet in mobile platform. In this paper, a method is proposed by combining a proposed tile-based algorithm with scrollViewDidScroll protocol of the iOS platform. With the tile-based algorithm, the panoramic views are divided into tiles and only tiles of interest are viewed on the mobile screen. Besides, the scrollViewDidScroll protocol of the iOS platform is used to link back the end of panoramic view with the start of the panoramic view to produce a cylindrical panoramic view. From here, the user can view the same output as panoramic views on a mobile device but using limited bandwidth, memory, and number of processors. Based on the evaluation, the respondents gave favorable response to the method.

Abstract: In this paper, we propose a three dimensional vision conversion based on cloud computing. Three dimensional video and image system become an important technology in consumer electronics field in latest decade. There are numerous three dimensional video and image formats for different 3D products. However, the three dimensional vision contents that are manufactured by different standards are difficult to exchange without complete three dimensional vision converters. Therefore, how to perform the three dimensional vision format converters to interchange different kinds of three dimension vision becomes an important research topic in academic and industry. Nevertheless, three dimensional vision processor and converter have high computing complexity. It is hard to perform whole three dimensional vision converter according to all kinds of international standards in client machine and portable device. At the same time, three dimensional visions often require a large number of storage spaces. It is also very difficult to record all kinds of three dimensional visions in local device. The above problem should be solved adopting different concepts. Therefore, we proposed cloud computing concept that establishes a complete three dimensional vision converter in cloud computing server and storage space in three dimensional vision clouds. The customer access the three dimensional vision rely on three dimensional vision cloud. The approach methodology solves the problems of computing complexity and storage space of tradition three dimensional vision converters and storage. The presented intact framework of three dimensional vision converters also provides a solution of related research in this paper.

Abstract: User authentication techniques such as the setting of passwords are gradually gaining importance as a means of managing important information stored in smartphones. Existing text–based password authentication schemes have the advantages of being quick and easy to use. However, they are problematic in that passwords are easily exposed to shoulder-surfing attack. In addition, a graphical password authentication scheme has the limitation of being difficult to apply to mobile device environments, in which a lot of information must be remembered and small-sized screens are provided. Therefore, in this paper, we propose a new hybrid password authentication scheme using a pocket billiard and a virtual joystick, which is secure against shoulder-surfing, brute force attack, and smudge attack and has excellent usability.

Abstract: Nowadays, network bandwidth and hardware technology are developing rapidly, resulting in the vigorous development of the Internet. However, cloud computing, an Internet-based development in which dynamically scalable and often virtualized resources are provided as a service over the Internet has become a significant issue. According to the characteristics of cloud computing, there are a lot of applications and data centers in the cloud-computing environment, hence, the issues of information and communication security and authentication must to be considered. However, the most of the studies on the security and authentication require large amounts of computing resource; therefore not suitable for the cloud-computing environment. In this paper, a lightweight computing protocol, Lightweight Authentication Protocol (LAP), is proposed to enhance the security of cloud computing environment and provide the authentication of service.