60 research outputs found

    An Improved Active Network Concept and Architecture for Distributed and Dynamic Streaming Multimedia Environments with Heterogeneous Bandwidths

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    A problem in todays Internet infrastructure may occur when a streaming multimedia application is to take place. The information content of video and audio signals that contain moving or changing scenes may simply be too great for Internet clients with low bandwidth capacity if no adaptation is performed. In order to satisfactorily reach clients with various bandwidth capacities some works such as receiver-driven multicast and resilient overlay networks (RON) have been developed. However these efforts mainly call for modification on router level management or place additional layer to the Internet structure, which is not recommended in the nearest future due to the highly acceptance level and widely utilization of the current Internet structure, and the lengthy and tiring standardization process for a new structure or modification to be accepted. We have developed an improved active network approach for distributed and dynamic streaming multimedia environment with heterogeneous bandwidth, such as the case of the Internet. Friendly active network system (FANS) is a sample of our approach. Adopting application level active network (ALAN) mechanism, FANS participants and available media are referred through its universal resource locator (url). The system intercepts traffic flowing from source to destination and performs media post-processing at an intermediate peer. The process is performed at the application level instead of at the router level, which was the original approach of active networks. FANS requires no changes in router level management and puts no additional requirement to the current Internet architecture and, hence, instantly applicable. In comparison with ALAN, FANS possesses two significant differences. From the system overview, ALAN requires three minimum elements: clients, servers, and dynamic proxy servers. FANS, on the other hand, unifies the functionalities of those three elements. Each of peers in FANS is a client, an intermediate peer, and a media server as well. Secondly, FANS members tracking system dynamically detects the existence of a newly joined computers or mobile device, given its url is available and announced. In ALAN, the servers and the middle nodes are priori known and, hence, static. The application level approach and better performance characteristics distinguished also our work with another similar work in this field, which uses router level approach. The approach offers, in general, the following improvements: FANS promotes QoS fairness, in which clients with lower bandwidth are accommodated and receive better quality of service FANS introduces a new algorithm to determine whether or not the involvement of intermediate peer(s) to perform media post-processing enhancement services is necessary. This mechanism is important and advantageous due to the fact that intermediate post-processing increases the delay and, therefore, should only be employed selectively. FANS considers the size of media data and the capacity of clients bandwidth as network parameters that determine the level of quality of service offered. By employing the above techniques, our experiments with the Internet emulator show that our approach improves the reliability of streaming media applications in such environment

    Color image quality measures and retrieval

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    The focus of this dissertation is mainly on color image, especially on the images with lossy compression. Issues related to color quantization, color correction, color image retrieval and color image quality evaluation are addressed. A no-reference color image quality index is proposed. A novel color correction method applied to low bit-rate JPEG image is developed. A novel method for content-based image retrieval based upon combined feature vectors of shape, texture, and color similarities has been suggested. In addition, an image specific color reduction method has been introduced, which allows a 24-bit JPEG image to be shown in the 8-bit color monitor with 256-color display. The reduction in download and decode time mainly comes from the smart encoder incorporating with the proposed color reduction method after color space conversion stage. To summarize, the methods that have been developed can be divided into two categories: one is visual representation, and the other is image quality measure. Three algorithms are designed for visual representation: (1) An image-based visual representation for color correction on low bit-rate JPEG images. Previous studies on color correction are mainly on color image calibration among devices. Little attention was paid to the compressed image whose color distortion is evident in low bit-rate JPEG images. In this dissertation, a lookup table algorithm is designed based on the loss of PSNR in different compression ratio. (2) A feature-based representation for content-based image retrieval. It is a concatenated vector of color, shape, and texture features from region of interest (ROI). (3) An image-specific 256 colors (8 bits) reproduction for color reduction from 16 millions colors (24 bits). By inserting the proposed color reduction method into a JPEG encoder, the image size could be further reduced and the transmission time is also reduced. This smart encoder enables its decoder using less time in decoding. Three algorithms are designed for image quality measure (IQM): (1) A referenced IQM based upon image representation in very low-dimension. Previous studies on IQMs are based on high-dimensional domain including spatial and frequency domains. In this dissertation, a low-dimensional domain IQM based on random projection is designed, with preservation of the IQM accuracy in high-dimensional domain. (2) A no-reference image blurring metric. Based on the edge gradient, the degree of image blur can be measured. (3) A no-reference color IQM based upon colorfulness, contrast and sharpness

    Faculty Publications & Presentations, 2005-2006

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    Wireless sensor systems in indoor situation modeling II (WISM II)

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    Documentation Driven Software Development

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    The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an official Department of the Army position, policy or decision, unless so designated by other documentation.Our objective is to develop an integrated, systematic, documentation centric approach to software development, known as Documentation Driven Software Development (DDD). The research issues for DDD are creation and application of three key documenting technologies that will drive the development process and a Document Management System (DMS) that will support them. These technologies address (1) representations for active documents; (2) representations for repositories; (3) methods for analysis, transformation, and presentation of this information. In addition, we explored new possibilities for computed-aided interfaces that help humans with routine tasks. In doing so we applied Cognitive Science and machine learning methods to design user interfaces that can learn and assist users. We also expanded our work in the area of integration of ontologies from heterogeneous sources. Specifically, we studied Knowledge System Integration Ontology (KSIO) that aligns data and information systems with current situational context for the efficient knowledge collection, integration and transfer. The role of ontology is to organize and structure knowledge (e.g. by standardized terminology) so that semantic queries and associations become more efficient. We assessed the degree to which natural language processing can be usefully applied to the analysis of requirement changes and their impact on system structure and implementation

    On the cyber security issues of the internet infrastructure

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    The Internet network has received huge attentions by the research community. At a first glance, the network optimization and scalability issues dominate the efforts of researchers and vendors. Many results have been obtained in the last decades: the Internet’s architecture is optimized to be cheap, robust and ubiquitous. In contrast, such a network has never been perfectly secure. During all its evolution, the security threats of the Internet persist as a transversal and endless topic. Nowadays, the Internet network hosts a multitude of mission critical activities. The electronic voting systems and financial services are carried out through it. Governmental institutions, financial and business organizations depend on the performance and the security of the Internet. This role confers to the Internet network a critical characterization. At the same time, the Internet network is a vector of malicious activities, like Denial of Service attacks; many reports of attacks can be found in both academic outcomes and daily news. In order to mitigate this wide range of issues, many research efforts have been carried out in the past decades; unfortunately, the complex architecture and the scale of the Internet make hard the evaluation and the adoption of such proposals. In order to improve the security of the Internet, the research community can benefit from sharing real network data. Unfortunately, privacy and security concerns inhibit the release of these data: its suffices to imagine the big amount of private information (e.g., political preferences or religious belief) it is possible to get while reading the Internet packets exchanged between users and web services. This scenario motivates my research, and represents the context of this dissertation which contributes to the analysis of the security issues of the Internet infrastructures and describes relevant security proposals. In particular, the main outcomes described in this dissertation are: • the definition of a secure routing protocol for the Internet network able to provide cryptographic guarantees against false route announcement and invalid path attack; • the definition of a new obfuscation technique that allow the research community to publicly release their real network flows with formal guarantees of security and privacy; • the evidence of a new kind of leakage of sensitive informations obtained hacking the models used by sundry Machine Learning Algorithms

    Annual Research Report, 2009-2010

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    Annual report of collaborative research projects of Old Dominion University faculty and students in partnership with business, industry and governmenthttps://digitalcommons.odu.edu/or_researchreports/1001/thumbnail.jp

    Multimedia

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    The nowadays ubiquitous and effortless digital data capture and processing capabilities offered by the majority of devices, lead to an unprecedented penetration of multimedia content in our everyday life. To make the most of this phenomenon, the rapidly increasing volume and usage of digitised content requires constant re-evaluation and adaptation of multimedia methodologies, in order to meet the relentless change of requirements from both the user and system perspectives. Advances in Multimedia provides readers with an overview of the ever-growing field of multimedia by bringing together various research studies and surveys from different subfields that point out such important aspects. Some of the main topics that this book deals with include: multimedia management in peer-to-peer structures & wireless networks, security characteristics in multimedia, semantic gap bridging for multimedia content and novel multimedia applications
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