Future multimedia satellite will provide a multitude of services to end users ranging from narrow band to broad band (voice, video, internet access...). We consider here users sharing a common access carrier through t...
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The access to Online Social Networks (OSN) and to media shared over these platforms account for around 20% of today's mobile Internet traffic. For mobile device users, the access to media content and specifically ...
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ISBN:
(纸本)9781479958047
The access to Online Social Networks (OSN) and to media shared over these platforms account for around 20% of today's mobile Internet traffic. For mobile device users, the access to media content and specifically videos is still challenging and costly. Mobile contracts usually have a data cap and connection qualities can vary greatly, depending on the cellular network coverage. Prefetching mechanisms that fetch content items beforehand, in times when the mobile device is connected to a WiFi network, have a high potential to address these problems. Yet, such a mechanism can only be effective if relevant content can be predicted with a high accuracy. Therefore, in this paper, an analysis of content properties and their potential for prediction are presented. An initial user study with 14 Facebook users running an app on their mobile device was conducted. The results show that video consumption is very diverse across the users. This work discusses the evaluation setup, the data analysis, and their potential to define an effective prefetching algorithm.
The rapid growth of multimedia communication systems has expanded the High-Efficiency Video Coding (HEVC) security applications precipitously. Therefore, there is an urgent, elevated need to protect and secure the HEV...
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The rapid growth of multimedia communication systems has expanded the High-Efficiency Video Coding (HEVC) security applications precipitously. Therefore, there is an urgent, elevated need to protect and secure the HEVC content during streaming and communication over insecure channels to ensure the privacy of HEVC data against intruders and attackers. This paper introduces an optical HEVC cipher algorithm based on bit-plane 3D-JST (Three-Dimensional Jigsaw Transform) and multistage 2D-FrFT (Two-Dimensional Fractional Fourier Transform) encryption. The main advantage of employing 3D-JST is its unitary transform that has an inverse transform used to reorganize the HEVC frame-blocks in an indiscriminately way. The proposed algorithm embraces the cascaded 2D-FrFT encryption in the optical domain using a single arbitrary phase code;to be executed all optically with a lone lens. The suggested algorithm utilizes the two 2D-FrFT stages with distinct kernels in mutually dimensions separated by employing the arbitrary phase code. A foregoing bit-plane permutation stage is conducted on the input HEVC frames before the 3D-JST and 2D-FrFT processes to accomplish a high robustness and security level. To validate the efficacy of the proposed cryptography algorithm for secure HEVC streaming, a comprehensive evaluation framework has been introduced and followed to (a) test HEVC streams against different statistical cryptographic metrics, (b) compare the proposed algorithm with recent related works whether optical-based or digital-based algorithms and (c) study the impact of different security attacks on its performance. The evaluation results show a secure and efficient proposed cryptography algorithm that outperforms the conventional and related cryptography algorithms in terms of all examined evaluation metrics.
Spatial audio becomes increasingly popular in domestic and mobile multimedia applications. Evaluating quality of experience (QoE) of such applications requires the development of algorithms capable of identification a...
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ISBN:
(纸本)9783319986784;9783319986777
Spatial audio becomes increasingly popular in domestic and mobile multimedia applications. Evaluating quality of experience (QoE) of such applications requires the development of algorithms capable of identification and quantification of perceptual characteristics of spatial audio scenes. This paper introduces a method for the automatic categorization of surround sound recordings using a criterion based on the distribution of foreground and background audio content around a listener. The principles of the method were demonstrated using a study in which a corpus of 110 five-channel surround sound recordings was computationally classified according to the two basic spatial audio scene categories. In order to develop the proposed method a novel metric, representing spatial audio characteristics, was identified. Moreover, five machine learning algorithms, including neural networks, random forests and support vector machines, were employed and their performance compared. According to the obtained results, the proposed method was capable of categorization of surround sound recordings reaching accuracy of 99%.
E-health is greatly impacting on information distribution and availability within the health services, hospitals and to the public. Previous research has addressed the development of system architectures with the aim ...
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This paper presents our latest work oil identifying frame content types for understanding learning media content. In particular, we categorize frames into six classes namely, slide, web-page, instructor, audience, pic...
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ISBN:
(纸本)0780393317
This paper presents our latest work oil identifying frame content types for understanding learning media content. In particular, we categorize frames into six classes namely, slide, web-page, instructor, audience, picture-in-picture and miscellaneous, which make up salient narrative modes in learning videos. Various image and video analysis approaches are explored to achieve this task. Preliminary experiments carried out on three recorded seminars have yielded encouraging results. The identification of fine-grained visual content types can assist us in content understanding, access, browsing and searching of generic learning videos.
The distribution of multimedia files brings new challenges to the problem of replica placement in content distribution networks (CDN) and invalidates several assumptions underlying the existing solutions. In this pape...
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ISBN:
(纸本)0780378024
The distribution of multimedia files brings new challenges to the problem of replica placement in content distribution networks (CDN) and invalidates several assumptions underlying the existing solutions. In this paper we formulate a new model for the problem of replica placement to accommodate these new characteristics. We perform a theoretical analysis of the cost of distributing multimedia files over CDNs and find out that, contrary to the intuition, deploying as many replicas as possible is not always a good strategy. We then propose several replica placement algorithms that can determine the optimal number of replicas we should select from a given set of potential sites. By simulation we demonstrate that the performance of clients may degrade if we choose too many sites for replica placement.
Various types of multimedia objects are distributed to peer computers (peers) in peer-to-peer (P2P) overlay networks. An application has to find target peers which can support enough quality of service (QoS) of target...
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ISBN:
(纸本)0769522815
Various types of multimedia objects are distributed to peer computers (peers) in peer-to-peer (P2P) overlay networks. An application has to find target peers which can support enough quality of service (QoS) of target multimedia objects. We discuss acquaintance relations of peers with respect to what objects each peer holds, is allowed to manipulate, and can grant access rights on. We discuss a charge-basedflooding (CBF) algorithm to find target peers based on charge and acquaintance concepts so that areas in P2P overlay networks where target peers are expected to exist are more deeply searched. We evaluate the CBF algorithm compared with a traditional flooding algorithm in terms of the number of messages transmitted in networks.
Large-scale multimedia semantic concept detection requires real-time identification of a set of concepts in streaming video or large image datasets. The potentially high data volumes of multimediacontent, and high co...
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ISBN:
(纸本)9781424442904
Large-scale multimedia semantic concept detection requires real-time identification of a set of concepts in streaming video or large image datasets. The potentially high data volumes of multimediacontent, and high complexity associated with individual concept detectors, have hindered the practical deployment of many current solutions. In this paper, we present a summary of our work in building systems and applications for resource adaptive semantic concept detection in multimedia using large-scale distributed stream mining systems. We construct such concept detection applications as a hierarchical topology of individual concept detectors, and deploy them on distributed processing infrastructure. We then focus on dynamically configuring individual concept detectors to meet system imposed resource constraints while minimizing a penalty defined in terms of the misclassification cost. We present multiple centralized and distributed algorithms for this configuration, and describe the implemented application and system. We also verify through simulations that significant improvement in terms of accuracy of classification can be achieved through our approach.
This paper is on the scope of the use of virtual learning environments in higher education institutions. The aim is to understand between the school year of 2009/2010 to 2013/2014 the use of a virtual learning environ...
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ISBN:
(纸本)9781479983308
This paper is on the scope of the use of virtual learning environments in higher education institutions. The aim is to understand between the school year of 2009/2010 to 2013/2014 the use of a virtual learning environment of a Portuguese higher education institution in terms of publishing of contents by teachers, the type of contents published, the students access to these contents as well as the exploration of relationships between published content and access to these contents. The data were obtained by document analysis, using databases to retrieve the records of publication of contents and access, during the study period. The contents published by teachers were integrated into categories: PDF, Text Documents, Spreadsheets, Presentations, Images, Compressed Files and multimedia. Most of the contents were published in PDF format.
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