基于因特网的连续媒体交互技术研究

对基于因特网的多媒体会议系统的传输特性、要求和协议标准等进行了系统地研究。通过对因特网上多媒体会议系统的特殊需求和支持多媒体网络协议存在问题的分析,提出了因特网多媒体会议系统的总体设计方案,并在此基础上对连续媒体中音频会议系统的实现进行了试验。     

Dynamic framework to mining Internet of Things for multimedia services

The rapid and unprecedented technological advancements are currently dominated by two technologies. At one hand, we witness the rise of the Internet of Things (IoT) as the next evolution of the Internet. At the other hand, we witness a vast spread of social networks that connects people together socially and opens the door for people to share and express ideas, thoughts, and information. IoT is overpopulated by a vast number of objects, millions of multimedia services, and interactions. Therefore, the search of the right object that can provide the specific multimedia service is considered as an important issue. The merge of these two technologies resulted in new paradigm called Social IoT (SIoT). The main idea in SIoT is that every object can mine IoT in search for certain multimedia service. We investigate the issue of friends' management in SIoT and propose a framework to manage friends' requests. The proposed framework employs several mechanisms to better manage friends' relationships. The proposed framework consists of friend selection, friendship removal, and an update module. It proposes a weight-based algorithm and Naïve Bayes Classifier-based algorithm for the selection component. Moreover, a random service allocation model is proposed to construct service-specific network model. This model is then used in the simulation setup to examine the performance of different friends' management algorithms. The performance of the proposed framework is evaluated using simulation under different scenarios. The obtained simulation results show improvement over other strategies in terms of average degree of connections, average path length, local cluster coefficients, and throughput.     

Context-driven encrypted multimedia traffic classification on mobile devices

The Internet has been experiencing immense growth in multimedia traffic from mobile devices. The increase in traffic presents many challenges to user-centric networks, network operators, and service providers. Foremost among these challenges is the inability of networks to determine the types of encrypted traffic and thus the level of network service the traffic needs to maintain an acceptable quality of experience. Therefore, end devices are a natural fit for performing traffic classification since end devices have more contextual information about device usage and traffic. This paper proposes a novel approach that classifies multimedia traffic types produced and consumed on mobile devices. The technique relies on a mobile device’s detection of its multimedia context characterized by its utilization of different media input/output (I/O) components, e.g., camera, microphone, and speaker. We develop an algorithm, MediaSense, which senses the states of multiple I/O components and identifies the specific multimedia context of a mobile device in real-time. We demonstrate that MediaSense classifies encrypted multimedia traffic in real-time as accurately as deep learning approaches and with even better generalizability.     

Efficient surface reconstruction method for distributed CAD

This paper describes a new fast Reverse Engineering (RE) method for creating a 3D computerized model from an unorganized cloud of points. The proposed method is derived directly from the problems and difficulties currently associated with remote design over the Internet, such as accuracy, transmission time and representation at different levels of abstraction. With the proposed method, 3D models suitable for distributed design systems can be reconstructed in real time. The mesh reconstruction approach is based on aggregating very large scale 3D scanned data into a Hierarchical Space Decomposition Model (HSDM), realized by the Octree data structure. Then, a Connectivity Graph (CG) is extracted and filled with facets. The HSDM can represent both the boundary surface and the interior volume of an object. Based on the proposed volumetric model, the surface reconstruction process becomes robust and stable with respect to sampling noise. Moreover, the data received from different surface/volume sampling devices can be handled naturally. The hierarchical structure of the proposed volumetric model enables data reduction, while preserving significant geometrical features and object topology. As a result, reconstruction and transmission over the network are efficient. Furthermore, the hierarchical representation provides a capability for extracting models at desired levels of detail, thus enabling designers to collaborate at any product development stage: draft or detailed design.     

Internet electronic product catalogs: an approach beyond simple keywords and multimedia

Internet-based Electronic Product Catalogs (IEPCs) are one of the most important parts of electronic markets. They are the merchant’s interactive interface towards online customers. Based on the features of their carrier, the interactive and ubiquitous Internet, IEPCs are online, permanently up-to date, and enable customization as well as direct communication between seller and buyer. Even though IEPCs are more sophisticated compared to paper-based catalogs, the search for products on the Internet is still a cumbersome process. Surveys show, that online customers have difficulties navigating through merchants’ sites to find the products they need. In this paper, a comprehensive approach for IEPCs as complex information spaces will be presented. First a detailed requirements analysis for IEPCs will be conducted. Then a concept for organizing information within IEPCs, which goes beyond simple keywords and multimedia, will be presented. Finally, technologies for its implementation will be identified.     

VoD on steroids : Optimized content delivery using distributed video servers over best-effort Internet

This paper addresses the problem of delivering a long-duration continuous media document, typically a movie, over unreliable communication links like the ones that make up the Internet. Packet loss/drop is one of the main problems that plague Internet's use for offering multimedia services. The framework presented here addresses analytically this problem by offering closed-form solutions for partitioning and scheduling the delivery of a document by multiple spatially distributed servers. The goal is to offer uninterrupted playback to clients while minimizing their access-time.The solid mathematical foundation presented, enables the study of multi-server document delivery using unreliable communications for both CBR and VBR media. It is also shown how slow connections that would otherwise prevent the deployment of Movie-on-Demand class services, could be used to offer such services in an optimal manner. The paper also addresses the problem of optimally arranging the available servers.A rigorous simulation study that explores the potential of the proposed approach concludes the paper. Our simulations show a super-linear speedup in access-times and also the robustness of the proposed scheme, capable of handling unknown network conditions by shifting server “load”.     

Slingshot 3D: A synchronous haptic-audio-video game

Recent advances in multimedia and human computer interaction technologies have paved the way for rich contents across multiple media such as haptics, audio, and video. This paper introduces a multimodal game named the Slingshot 3D Game: an interactive and synchronous haptic-audio-video shooter game over the Internet network. The game incorporates two types of haptic feedback: tactile feedback using a haptic jacket and kinesthetic feedback using the Novint Falcon haptic interface. Furthermore, the game utilizes a depth camera to track the player's (upper) body movements and detect collisions between the player's body and the shot projectile. To promote availability and cost, the game uses the Internet network as the communication medium between the players, by utilizing the Admux communication framework [10]. The game design and implementation are detailed in this paper. Both the player performance analysis and the user satisfaction analysis have shown that the incorporation of synchronous haptic-video multimedia has enhanced the perception of player presence and the overall quality of performance.     

BOX: Browsing objects in XML

The latest Internet markup languages support the representation of structured information and vector graphics. In this paper we describe how these languages can be used to publish software engineering diagrams on the Internet. We introduce BOX, a portable, distributed and interoperable approach to browsing UML models with off‐the‐shelf technology. Our approach to browsing UML models leverages XML and related specifications, such as the Document Object Model (DOM), the XML Metadata Interchange (XMI) and the Vector Markup Language (VML). BOX translates a UML model that is represented in XMI into VML. VML can be directly displayed in Internet browsers, such as Microsoft's Internet Explorer 5. BOX enables software engineers to access and review UML models without the need to purchase licenses of tools that produced the models. BOX has been successfully evaluated in two industrial case studies. The case studies used BOX to make extensive domain and enterprise object models available to a large number of stakeholders over corporate intranets and the Internet. We show how XML and the BOX architecture can be applied to other software engineering notations. We also argue that the approach taken in BOX can be applied to other domains that have already started to adopt XML and have a need for graphic representation of XML information. These include browsing gene sequences, chemical molecule structures and conceptual knowledge representations. Copyright © 2000 John Wiley & Sons, Ltd.     

Packet Spacing: An Enabling Mechanism for Delivering Multimedia Content in Computational Grids

Streaming multimedia with UDP has become increasingly popular over distributed systems like the Internet. Scientific applications that stream multimedia include remote computational steering of visualization data and video-on-demand teleconferencing over the Access Grid. However, UDP does not possess a self-regulating, congestion-control mechanism; and most best-effort traffic is served by congestion-controlled TCP. Consequently, UDP steals bandwidth from TCP such that TCP flows starve for network resources. With the volume of Internet traffic continuing to increase, the perpetuation of UDP-based streaming will cause the Internet to collapse as it did in the mid-1980's due to the use of non-congestion-controlled TCP. To address this problem, we introduce the counter-intuitive notion of inter-packet spacing with control feedback to enable UDP-based applications to perform well in the next-generation Internet and computational grids. When compared with traditional UDP-based streaming, we illustrate that our approach can reduce packet loss over 50% without adversely affecting delivered throughput.     

Digital libraries and Web 3.0. The CallimachusDL approach

The constantly increasing volume of information available on the Internet is changing the forms of classification and access to data. Given the immense collection of information stored on the Internet, digital libraries constitute a fundamental subject of research. Among the challenges of classifying, locating and accessing knowledge in digital libraries tackling with the huge amount of resources the Web provides, improving digital libraries by means of different strategies, particularly, using semantics remains a promising and interesting approach. In this paper, CallimachusDL is presented, a semantics-based digital library which provides faceted search, enhanced access possibilities and a proof-of-concept implementation. CallimachusDL represents a novel approach to digital libraries, integrating social web and multimedia elements in a semantically annotated repository. The results of the implementation indicate that the features proposed in CallimachusDL are encouraging and extendable in the use of digital libraries.     

演员模型：一种多媒体数据表达模型

本文提出一种多媒体数据表达模型：演员模型，该模型建立在多媒体数据库概念模型基础之上，基于库所—时间Ｐｅｔｒｉ网，描述多媒体对象之间的时态关系，同时引入与变迁相关联的场景表达式，描述多媒体对象之间的空间关系，从而模拟多媒体数据的时空编组，文中形式化地定义了演员模型的抽象模型和实现模型，提出多媒体对象的表达算法以及多媒体数据库的查询模型．     

支持综合业务的Internet-ATM网络及互联

文中阐述了Ｉｎｔｅｒｎｅｔ上综合业务的模式,介绍了资源预订协议ＲＳＶＰ、Ｉｎｔｅｒｎｅｔ流协议ＳＴ－ＩＩ、资源预先预订协议ＲｅＲＡ和几种主要的Ｉｎｔｅｒｎｅｔ与ＡＴＭ主干网络的互联协议以及传统的ＴＣＰ／ＩＰ协议族的报文在ＡＴＭ网络中传送的协议ＩＰ ｏｖｅｒＡＴＭ;阐述了局域网模拟ＬＡＮＥ的体系结构及其实现的一个实例和ＡＴＭ上支持多种网络层议（如ＩＰ,ＩＰＸ／ＳＰＸ,ＡｐｐｌｅＴａｌｋ等）的规范ＭＰ     

网络流媒体服务器的机制与实现研究

网络流媒体服务器是指在IP网络上提供实时视频(音频)流服务的网络服务器,对服务器的机制与实现进行了深入研究,在RTP／RTCP协议和RTSP协议基础上,提出了“生产者线程-消费者线程”的架构,用面向对象的方法和事件驱动的机制实现服务器异步工作方式,充分利用系统资源,提高了服务器的并发性和实时性。基于反馈报文的流服务器流量自调节,解决了网络拥塞时实时数据传输的问题。     

A local approach for 3D object recognition through a set of size functions

In this paper, a local approach for 3D object recognition is presented. It is based on the topological invariants provided by the critical points of the 3D object. The critical points and the links between them are represented by a set of size functions obtained after splitting the 3D object into portions. A suitable similarity measure is used to compare the sets of size functions associated with the 3D objects. In order to validate our approach's recognition performance, we used different collections of 3D objects. The obtained scores are favourably comparable to the related work.     

Integration of control system design and implementation over the internet using the Jini technology

This paper describes an approach for the integration of control system software design, testing, and implementation over the Internet using the Java and Jini technologies. Process models and control systems are remotely designed and tested in a virtual laboratory (also called the virtual world), and then implemented in a physical plant (also called the real world) through an integrated environment. Although control system and process model designers and real‐site operators are geographically dispersed they work together as a team over the Internet to provide the maintenance support to all the authorized industrial processes. As a consequence, time and money can both be saved because there is no need for an expert of the control software supplier to travel to the site of the real plant and conduct on‐site implementation. A generic control system life cycle model is presented first in this paper. Then three enabling technologies including Java, Jini and WWW are briefly introduced. Taking advantage of the Java, Jini and WWW technologies, an Internet‐based general infrastructure is proposed to remotely facilitate process modelling, control system design, simulation, validation and on‐site implementation. An integrated environment is established to implement the infrastructure. A water tank with a liquid level control system is refereed as a case study to illustrate how the prototype of the integrated environment works over the Internet. Further work and the conclusions are given at the end. Copyright © 2003 John Wiley & Sons, Ltd.     

Aggregating expert predictions in a networked environment

This paper describes an approach for combining the classifications or predictions of n local experts into a single composite prediction. We describe a Java-based application that allows a user to select up to n prediction experts that provide information for assigning an object to one of two predetermined groups. An advantage of this type of application is that it is capable of interacting with the Internet in a relatively seamless way. We examine the accuracy and robustness of our technique by comparing the classification accuracy of our technique, a maximum entropy-based aggregation technique, and four classification methods on a real-world, two-group data-set concerned with bank failure prediction. The classificaiton methods studied in this work include Quinlan's C4.5 decision-tree classifier, logistic regression, mahalanobis distance measures, and a neural network classifier. Our model includes a fundamental component (i.e., a transaction manager) that helps improve the general performance of applications that perform network-based classification. This component is found to provide reliable and secure connections along with ways to direct traffic across the Internet. Our results suggest three major contributions: (1) a transaction manager increases the flexibility of a network-based classifier since it is capable of transacting with one or more specific types of prediction expert(s) over the Internet; (2) our approach tends to be more accurate than the individual classification methods we examined; and, (3) our approach can outperform a recently introduced statistically based aggregation technique.Scope and purposeThe emergence of the Internet has produced a need for employing new types of programming and research tools that are capable of accessing information resources located throughout the world. There is only a limited amount of research available in this area and this work describes a network-based tool that solves a two-group classification problem. The two-group classification problem in discriminant analysis is concerned with developing a rule for predicting to which of k=2 mutually exclusive groups an observation of unknown origin belongs. This problem commonly occurs in business and other areas, and a plethora of statistical and artificial intelligence (AI) techniques exist to help decision-makers effectively analyze their data. A number of recent studies have compared the classificatory performance of various AI techniques to the more traditional statistical techniques, however, decision makers are left in somewhat of a quandary about which of the many available classification techniques to use to solve a specific classification problem. This paper proposes a new aggregation technique that focuses on combining or aggregating the predictions from multiple classification techniques into a single composite prediction. Our approach provides a simple method for aggregating expert predictions coming from remote locations by combining Java and Common Object Request Broker Architecture (CORBA) into a general classification tool. Object-oriented models developed using Java are platform independent and can be easily modified. CORBA provides the services necessary to establish and manage network connections. Computational results show that our technique outperforms a recently introduced maximum entropy-based aggregation technique using a real-world data set.     

A case study in mapping conceptual designs to object‐relational schemas

The recent emergence of object‐relational technology into the commercial database market has caused new challenges for the implementation of conceptual database designs. This paper presents our experience with using the Oracle 8 object‐relational data model in the implementation of an engineering application described using the EXPRESS conceptual modeling language. EXPRESS is part of the engineering community's Standard for the Exchange of Product Data and can be characterized as a structurally object‐oriented modeling language, supporting the notion of entities, entity hierarchies, complex constraints on entity hierarchies, relationships and inverse relationships between entities, and user‐defined types. As a result, EXPRESS provides an excellent framework for studying the mapping of conceptual modeling concepts into an object‐relational model. In this paper, we describe the way in which the features of EXPRESS can be mapped into object‐relational features such as object tables, object references, and nested tables. We also describe the manner in which features such as member functions on object types, triggers, and stored procedures can be used to support the implementation of constraints associated with a conceptual schema. Although the mappings presented are specific to EXPRESS and Oracle 8, the mappings are generalizable to conceptual modeling languages and object‐relational models with similar features. Our work defines how traditional mapping concepts must be revised in order to make adequate use of the features now found in object‐relational models. As part of this paper, we also compare our mapping approach using Oracle 8 to mapping issues for the PostgreSQL object‐relational model and the Objectivity/DB object‐oriented data model. Copyright © 2000 John Wiley & Sons, Ltd.     

A Survey of Application Layer Techniques for Adaptive Streaming of Multimedia

Though the integrated services model and resource reservation protocol (RSVP) provide support for quality of service, in the current Internet only best-effort traffic is widely supported. New high-speed technologies such as ATM (asynchronous transfer mode), gigabit Ethernet, fast Ethernet, and frame relay, have spurred higher user expectations. These technologies are expected to support real-time applications such as video-on-demand, Internet telephony, distance education and video-broadcasting. Towards this end, networking methods such as service classes and quality of service models are being developed. Today's Internet is a heterogeneous networking environment. In such an environment, resources available to multimedia applications vary. To adapt to the changes in network conditions, both networking techniques and application layer techniques have been proposed. In this paper, we focus on the application level techniques, including methods based on compression algorithm features, layered encoding, rate shaping, adaptive error control, and bandwidth smoothing. We also discuss operating system methods to support adaptive multimedia. Throughout the paper, we discuss how feedback from lower networking layers can be used by these application-level adaptation schemes to deliver the highest quality content.