Wireless environments present many challenges for secure multimediaaccess, especial streaming media. The availability of varying network bandwidths and diverse receiver device processing powers and storage spaces dem...
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ISBN:
(纸本)0819451282
Wireless environments present many challenges for secure multimediaaccess, especial streaming media. The availability of varying network bandwidths and diverse receiver device processing powers and storage spaces demand scalable and flexible approaches that are capable of adapting to changing network conditions as well as device capabilities. To meet these requirements, scalable and fine granularity scalable (FGS) compression algorithms were proposed and widely adopted to provide scalable access of multimedia with interoperability between different services and flexible support to receivers with different device capabilities. Encryption is one of the most important security tools to protect content from unauthorized use. If a medium data stream is encrypted using non-scalable cryptography algorithms, decryption at arbitrary bit rate to provide scalable services can hardly be accomplished. If a medium compressed using scalable coding needs to be protected and non-scalable cryptography algorithms are used, the advantages of scalable coding may be lost. Therefore scalable encryption techniques are needed to provide scalability or to preserve the FGS adaptation capability (if the media stream is FGS coded) and enable intermediate processing of encrypted data without unnecessary decryption. In this paper, we will give an overview of scalable encryption schemes and present fine grained scalable encryption algorithm. One desirable feature for FGS compatible encryption schemes is to provide simplicity and flexibility in supporting scalable multimedia communication and multimediacontentaccess control in wireless environments.
Modality conversion is an important part in the content adaptation process of a Universal multimediaaccess system. The decision on modality conversion is dependent on terminal/network conditions and on the user prefe...
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Modality conversion is an important part in the content adaptation process of a Universal multimediaaccess system. The decision on modality conversion is dependent on terminal/network conditions and on the user preference. We propose a systematic and comprehensive approach to make decision on modality conversion in a UMA system. Our approach includes three integral components, (1) an overlapped content model, (2) a flexible specification of user preference on modality conversion, and (3) a resource allocation method to distribute resource to multiple contents.
multimedia data, which are direct reflections of the real world, have unlimited semantic interpretations within different application domains. In order to reuse information resources, in this paper, we provide a layer...
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ISBN:
(纸本)0889863806
multimedia data, which are direct reflections of the real world, have unlimited semantic interpretations within different application domains. In order to reuse information resources, in this paper, we provide a layered architecture of multimedia schema - raw multimedia layer, domain knowledge layer, and user profile layer. Raw multimedia layer provides non-semantic management of data, including storage allocations, buffer algorithms and strategies, and multimedia preprocessing facilities. Domain knowledge layer provides semantic-oriented management and access of multimedia data. Different domains can utilize different knowledge bases to support semantic interpretations. We use Frame and Semantic Network as the representation models for domain knowledge. content-based retrievals can be performed on different levels of visual object constructions or concept abstractions. Furthermore, since different individual users may have different interpretations for fuzzy specifications in their queries, user profiles are created and used to support fuzzy retrievals of multimedia data.
Traditional cryptography systems treat every portion of a message (a video, an image, or an audio) equally and encrypt the entire message as a whole. As a result, those security systems often have only two states: acc...
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Traditional cryptography systems treat every portion of a message (a video, an image, or an audio) equally and encrypt the entire message as a whole. As a result, those security systems often have only two states: acc...
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Traditional cryptography systems treat every portion of a message (a video, an image, or an audio) equally and encrypt the entire message as a whole. As a result, those security systems often have only two states: access authorization and access denial. To facilitate multi-level access control with interoperability, scalable security mechanism is needed. Further, the availability of varying network bandwidth and diverse receiver device capabilities demand scalable and flexible approaches that are capable of adapting to changing network conditions as well as device capabilities. In this paper, we describe a multimedia encryption scheme that supports scalability. One desirable feature of the proposed scheme is its simplicity and flexibility in supporting scalable contentaccess control.
One of the main challenges facing web-based multimediacontent creators today is the development of cost-effective digital media content for courseware that is reusable and interoperable. Given this, we propose the de...
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ISBN:
(纸本)0780379659
One of the main challenges facing web-based multimediacontent creators today is the development of cost-effective digital media content for courseware that is reusable and interoperable. Given this, we propose the design and implementation of a model to manage the multimedia and meta-data within a system of related topics in a course that is delivered via electronic lectures. This model not only supports the re-purposing and interchange of a course's digital media content, but also preserves the semantic dependencies and associated media-mapping, of pre-requisite and co-requisite knowledge within a course. Coarse grain or topic-based segmentations of an electronic lecture are used as building blocks to automatically create new, media-rich, electronic lecture experiences of interest to a user and subject to the constraints imposed by the model.
Encryption is one of the most important security tools for secure message communication. There is increasing need for secure digital multimedia communication technologies to restrict unauthorized access. Prior to the ...
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Encryption is one of the most important security tools for secure message communication. There is increasing need for secure digital multimedia communication technologies to restrict unauthorized access. Prior to the availability of variable bit rate (VBR) communication services, systems typically treat every portion of a message equally and encrypt each and every bit of a message that is decrypted at the same rate as encrypted. Hence, encryption/decryption processes at both ends of the network were required to operate at the same rate. The advent of VBR multimedia communication services require new cryptography system implementations that can operate at different data rates, i.e., be scaled to different speed, different network bandwidth, and diverse receiver device capabilities. In this paper, we describe a progressive and scalable encryption scheme that supports scalability. One desirable feature of the proposed scheme is its simplicity and flexibility in supporting scalable multimedia communication and multimediacontentaccess control.
As the usage of wireless packet data services increases, wireless carriers today are faced with the challenge of offering multimedia applications with QoS requirements within current 3G data networks. End-to-end QoS r...
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ISBN:
(纸本)0819451258
As the usage of wireless packet data services increases, wireless carriers today are faced with the challenge of offering multimedia applications with QoS requirements within current 3G data networks. End-to-end QoS requires support at the application, network, link and medium access control (MAC) layers. We discuss existing CDMA2000 network architecture and show its shortcomings that prevent supporting multiple classes of traffic at the Radio access Network (RAN). We then propose changes in RAN within the standards framework that enable support for multiple traffic classes. In addition, we discuss how Session Initiation Protocol (SIP) can be augmented with QoS signaling for supporting end-to-end QoS. We also review state of the art scheduling algorithms at the base station and provide possible extensions to these algorithms to support different classes of traffic as well as different classes of users.
When speaking of wireless and mobile Internet, we often assume that a bi-directional access network must be within reach. Usually we see GPRS, UMTS and wireless LANs as carriers supporting the Internet access service....
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ISBN:
(纸本)0780376617
When speaking of wireless and mobile Internet, we often assume that a bi-directional access network must be within reach. Usually we see GPRS, UMTS and wireless LANs as carriers supporting the Internet access service. This service consequently provides a basis for browsing and retrieving a wealth of digital multimediacontent upon user request. However, there are alternative means to deliver digital content to mobile users. Indeed, general content and content formats are independent from various communication methods. In this paper we focus on an alternative content delivery method - content push over terrestrial IP data broadcasting. To give a concrete context for discussion we assume DVB-T as transmission technology. The unidirectional, wide-band, shared channel suits especially well delivery service that targets multiple end users on the move. Applied to mobile communications, IP data broadcasting proves to complement the traditional mobile Internet access service provided over bi-directional accesssystems. From the viewpoint of international standards developing organizations, we tackle the issues needed to establish a globally inter-operable IP datacast baseline as a service platform.
Guaranteed QoS for multimedia applications requires support from the connecting network and the communicating parties. However, in many communications through the Internet, the backbones offer only best-effort service...
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ISBN:
(纸本)0889863806
Guaranteed QoS for multimedia applications requires support from the connecting network and the communicating parties. However, in many communications through the Internet, the backbones offer only best-effort service but are usually over-provisioned and, thus provide sufficient quality. The problems are often in the access networks that may become the bottleneck, especially when they have wireless links. Moreover, current content servers do not support QoS signaling. It would be useful if end hosts could reserve at least local resources at the access network, especially wireless link resources. Additionally, for mobile nodes the continuity of QoS is enhanced if resource signaling can be localized and coupled with mobility management. This paper presents a simple enhancement to RSVP, which allows initial resource reservations and re-reservations due to host mobility to be done locally in an access network.
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