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Walsh-like nonlinear phase orthogonal codes for direct sequence CDMA communications

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2007年第7期55卷 3800-3806页

作者： Akansu, Ali N. Poluri, Radha New Jersey Inst Technol Dept Elect & Comp Engn Newark NJ 07102 USA

Walsh codes are perfectly orthogonal binary (antipodal) block codes that found their use in many popular applications over several decades including synchronous multiuser communications. It is well known in the literature that they perform poorly for the case of asynchronous multiuser communications. Therefore, the near-orthogonal and nonlinear phase Gold codes with better performance are the preferred user codes in asynchronous direct sequence code division multiple access (DS-CDMA) communications standards. In this paper, we relaxed linear phase requirements and new sets of Walsh-like nonlinear phase binary orthogonal user codes (transforms) are obtained for asynchronous and synchronous spread spectrum multiuser communications. It is shown that the proposed binary user code family outperforms the Walsh codes significantly and they match in performance with the popular, nearly orthogonal Gold codes closely for asynchronous multiuser communications in additive white Gaussian noise (AWGN) channels. It is also shown that all. of the binary code families considered in this paper performed comparable for Rayleigh flat-fading channels. We present in this paper that there are a good number of such desirable code sets available in the binary sample space with different transform sizes. These new binary sets with good performance and flexible code lengths might help us to improve the spread spectrum multiplexing capabilities of future wireline and wireless CDMA communications systems.

关键词： additive white Gaussian noise (AWGN) channel code division multiple access (CDMA) Gold sequences orthogonal binary codes Rayleigh flat-fading channel Walsh sequences

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Semantics and image content integration for pulmonary nodule interpretation in thoracic computed tomography

Semantics and image content integration for pulmonary nodule...

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Medical Imaging 2007 Conference

作者： Raicu, Daniela S. Varutbangkul, Ekarin Cisneros, Janie G. Furst, Jacob D. Channin, David S. Armato, Samuel G., iii Depaul Univ Intelligent Multimedia Proc Lab Sch Comp Sci Telecommun & Informat Syst Chicago IL 60604 USA Northwestern Univ Med Sch Dept Radiol Chicago IL 60611 USA Univ Chicago Dept Radiol Chicago IL 60637 USA

ISBN: (纸本)9780819466303

Useful diagnosis of lung lesions in computed tomography (CT) depends on many factors including the ability of radiologists to detect and correctly interpret the lesions. Computer-aided Diagnosis (CAD) systems can be used to increase the accuracy of radiologists in this task. CAD systems are, however, trained against ground truth and the mechanisms employed by the CAD algorithms may be distinctly different from the visual perception and analysis tasks of the radiologist. In this paper, we present a framework for finding the mappings between human descriptions and characteristics and computed image features. The data in our study were generated from 29 thoracic CT scans collected by the Lung Image Database Consortium (LIDC). Every case was annotated by up to 4 radiologists by marking the contour of nodules and assigning nine semantic terms to each identified nodule;fifty-nine image features were extracted from each segmented nodule. Correlation analysis and stepwise multiple regression were applied to find correlations among semantic characteristics and image features and to generate prediction models for each characteristic based on image features. From our preliminary experimental results, we found high correlations between different semantic terms (margin, texture), and promising mappings from image features to certain semantic terms (texture, lobulation, spiculation, malignancy). While the framework is presented with respect to the interpretation of pulmonary nodules in CT images, it can be easily extended to find mappings for other modalities in other anatomical structures and for other image features.

关键词： LIDC shape texture stepwise multiple regression correlation analysis

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OSGi Platform for UPnP Audiovisual Service Delivery

OSGi Platform for UPnP Audiovisual Service Delivery

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Workshop on Intelligent Solutions in Embedded systems

作者： Javier Martinez Natividad Martinez Madrid Ralf Seepold Departamento de Ingeniería Telemática Universidad Carlos III de Madrid Leganes Spain

ISBN: (纸本)9788489315471

There is continuously increasing number of devices available which support multimedia management and enable capabilities of interconnection beyond the borders of a Residential Gateway. This paper focuses on devices providing multimedia content (Media Server) and devices reproducing the contents (Media Renders). The objective is to discover, manage and use remote devices like local resources. The setup and configuration should be easy to manage for service providers and transparent for the end users that access to remote services. The paper presents a solution supporting devices implementing UPnP A V that are integrated into an OSGi platform implemented in a heterogeneous scenario with multiple devices and services.

关键词： multimedia systems Network servers Quality of service Protocols Home automation Web server Mobile handsets Resource management Nonhomogeneous media DVD

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Unwanted SMTP Paths and Relays

Unwanted SMTP Paths and Relays

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International Conference on Communication systems Software and Middleware (COMSWARE)

作者： Srikanth Palla Ram Dantu Department of Computer Science University of North Texas Denton TX USA

Based on the social interactions of an email user, incoming email traffic can be divided into different categories such as, telemarketing, Opt-in family members and friends. Due to a lack of knowledge in the different categories, most of the existing spam filters are prone to high false positives and false negatives. Moreover, a majority of the spammers obfuscate their email content inorder to circumvent the content-based spam filters. However, they do not have access to all the fields in the email header. Our classification method is based on the path traversed by email (instead of content analysis) since we believe that spammers cannot forge all the fields in the email header. We based our classification on three kinds of analyses on the header: i) EndToEnd path analysis, which tries to establish the legitimacy of the path taken by an email and classifies them as either spam or non-spam; ii) Relay analysis, which verifies the trustworthiness of the relays participating in the relaying of emails; iii) Emails wantedness analysis, which measure the recipients wantedness of the senders emails. We use the IMAP message status flags such as, message has been read, deleted, answered, flagged, and draft as an implicit feed back from the user in Emails wantedness analysis. Finally we classify the incoming emails as i) socially close (such as, legitimate emails from family, and friends), ii) socially distinct emails from strangers, iii) spam emails (for example, emails from telemarketers, and spammers) and iv) opt-in emails. Based on the relation between spamminess of the path taken by spam emails and the unwantedness values of the spammers, we classify spammers as i) prospective spammers, ii) suspects, iii) recent spammers and iv) serial spammers. Overall, our method resulted in far less false positives compared to current filters like SpamAssassin. We achieved a precision of 98.65% which is better than the precisions achieved by SPF and DNSBL blacklists.

关键词： Relays Filters Unsolicited electronic mail Computer science multimedia communication Counterfeiting Web page design Credit cards Information security Legislation

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System support for pervasive multimedia systems

System support for pervasive multimedia systems

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作者： Liu, Xiaotao University of Massachusetts Amherst

学位级别：Ph.D.

The proliferation of multimedia-capable mobile devices, such as laptops, personal digital assistants (PDA), and cellular telephones, has lend to an explosive increase of multimedia contents. With the increasing capacities of disk storage, this trend has encouraged users to create ever-larger personal digital libraries of audios, pictures, and videos. The prevalence of small and mobile devices such as sensors and RFID tags is expected to create an ubiquitous computing environment. This ubiquitous environment can provide us pervasive locationing and identification services, and further can create sensor data streams encoding object’s location and identity which are the context of media capture. The concurrence of these two trends enable a new set of multimedia systems that we refer to as Pervasive multimedia systems. Pervasive multimedia systems enable users to create, access and navigate large volumes of multimedia content on a variety of personal mobile devices. Designing these pervasive multimedia systems face three major challenges: (i) achieving energy efficiency for the battery-powered mobile devices; (ii) searching and retrieving media content in a fast and human-friendly manner; and (iii) identifying and locating in scalable and maintainable fashions. In this thesis, We propose techniques that provide system support for pervasive multimedia systems to address these challenges. Due to the power constraints, battery-powered mobile devices impose requirements of energy efficiency. On the other hand, the real-time nature of multimedia applications makes it challenging to trade off application's performance with energy savings. To achieve energy efficiency without sacrificing application's quality-of-service (QoS), We have developed power management techniques using application domain-specific knowledge and time-series-based models. Our approaches can reduce the power consumption of mobile devices significantly, while at the same time still meet the QoS requirement

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SYSTEM SUPPORT FOR PERV ASIVE multimedia systems

SYSTEM SUPPORT FOR PERV ASIVE MULTIMEDIA SYSTEMS

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作者： XIAOTAO LIU University of Massachusetts Amherst

学位级别：博士

The proliferation of multimedia-capable mobile devices, such as laptops, personal digi- tal assistants (PDA), and cellular telephones, has lend to an explosive increase of multime- dia contents. With the increasing capacities of disk storage, this trend has encouraged users to create ever-larger personal digital libraries of audios, pictures, and videos. The preva- lence of small and mobile devices such as sensors and RFID tags is expected to create an ubiquitous computing environment. This ubiquitous environment can provide us pervasive locationing and identification services, and further can create sensor data streams encoding object's location and identity which are the context of media capture. The concurrence of these two trends enable a new set of multimedia systems that we refer to as Pervasive multimedia systems. Pervasive multimedia systems enable users to create, access and navigate large volumes of multimedia content on a variety of personal mobile devices. Designing these pervasive multimedia systems face three major challenges: (i) achiev- ing energy efficiency for the battery-powered mobile devices; (ii) searching and retrieving media content in a fast and human-friendly manner; and (iii) identifying and locating in scalable and maintainable fashions. In this thesis, We propose techniques that provide system support for pervasive multimedia systems to address these challenges. Due to the power constraints, battery-powered mobile devices impose requirements of energy efficiency. On the other hand, the real-time nature of multimedia applications makes it challenging to trade off application's performance with energy savings. To achieve energy efficiency without sacrificing application's quality-of-service (QoS), We have de- veloped power management techniques using application domain-specific knowledge and time-series-based models. Our approaches can reduce the power consumption of mobile devices significantly, while at the same time still meet the QoS r

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content based description of audio in the context of AXMEDIS

Content based description of audio in the context of AXMEDIS

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2nd International Conference on Automated Production of Cross Media content for Multi-Channel Distribution

作者： Scaringella, Nicolas Schmucker, Martin Arnold, Michael Swiss Fed Inst Technol EPFL Signal Proc Inst ITS LTS 3 CH-1015 Lausanne Switzerland Fraunhofer Inst Comp Graph Res Darmstadt Germany

ISBN: (纸本)9780769526256

The enormous growth of digital music databases has led to a comparable growth in the need for methods that help users organize and access such information. One area in particular that has seen much recent research activity is the use of automated techniques to describe audio content and to allow its identification, browsing and retrieval. This paper presents algorithms for audio content analysis, description and identification that are developed and implemented in the context of the AXMEDIS project.

关键词： Database systems

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9th IFIP/IEEE International Conference on Management of multimedia and Mobile Networks and Services, MMNS 2006

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9th IFIP/IEEE International Conference on Management of multimedia and Mobile Networks and Services, MMNS 2006

ISBN: (纸本)3540476547

The proceedings contain 26 papers. The special focus in this conference is on multimedia over wireless, Mobile Ad-Hoc networks, Video streaming, Short papers, Short papers, Bandwidth provisioning and control and multimedia over Wireless (2). The topics include: Enhanced multimedia and Real-Time Stream Throughput in Wireless Ad-Hoc LAN Using Distributed Virtual Channel Based MAC, Adaptive Streaming of Combined Audio/Video content over Wireless Networks, Management of IEEE 802.11e Wireless LAN for Realtime QoS-Guaranteed Teleconference Service with Differentiated H.264 Video Transmission, Link Available Bandwidth Monitoring for QoS Routing with AODV in Ad Hoc Networks, An Efficient and Robust Service Discovery Protocol for Dynamic MANETs, Modeling Energy Consumption in Error-Prone IEEE 802.11-Based Wireless Ad-Hoc Networks, MaVIS: Media-aware Video Streaming Mechanism, On the Power of Cooperation in multimedia Caching, Delay Constrained Spatio-temporal Video Rate Control for Time-Varying Rate Channels, A Scalable Framework for content Replication in Multicast-Based content Distribution Networks, VidShare: A Management Platform for Peer-to-Peer multimedia Asset Distribution Across Heterogeneous access Networks with Intellectual Property Management, A Service-Oriented Framework to Promote Interoperability Among DRM systems, A Distributed Hierarchical Structure for Object Networks Supporting Human Activity Recognition, A Bandwidth-Broker Based Inter-domain SLA Negotiation, Efficiency of Loss Differentiation algorithms in 802.11 Wireless Networks, Towards Autonomic Handover Decision Management in 4G Networks, Evaluation of an Intelligent Utility-Based Strategy for Dynamic Wireless Network Selection and Overlays on Wireless Mesh Networks: Implementation and Cross-Layer Searching.

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BIRAM: A content-based image retrieval framework for medical images

BIRAM: A content-based image retrieval framework for medical...

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Medical Imaging 2006 Conference

作者： Moreno, Ramon A. Furuie, Sergio S. Univ Sao Paulo Sch Med Heart Inst InCor Sao Paulo Brazil Univ Sao Paulo Polytech Sch EPUSP Sao Paulo Brazil

ISBN: (纸本)0819464244

In the medical field, digital images are becoming more and more important for diagnostics and therapy of the patients. At the same time, the development of new technologies has increased the amount of image data produced in a hospital. This creates a demand for access methods that offer more than text-based queries for retrieval of the information. In this paper is proposed a framework for the retrieval of medical images that allows the use of different algorithms for the search of medical images by similarity. The framework also enables the search for textual information from an associated medical report and DICOM header information. The proposed system can be used for support of clinical decision making and is intended to be integrated with an open source picture, archiving and communication systems (PACS). The BIRAM has the following advantages: (i) Can receive several types of algorithms for image similarity search;(ii) Allows the codification of the report according to a medical dictionary, improving the indexing of the information and retrieval;(iii) The algorithms can be selectively applied to images with the appropriated characteristics, for instance, only in magnetic resonance images. The framework was implemented in Java language using a MS access 97 database. The proposed framework can still be improved, by the use of regions of interest (ROI), indexing with slim-trees and integration with a PACS Server.

关键词： CBIR medical image information retrieval

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Affinity Hybrid Tree: An Indexing Technique for content-Based Image Retrieval in multimedia Databases

Affinity Hybrid Tree: An Indexing Technique for Content-Base...

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IEEE International Symposium on multimedia

作者： Kasturi Chatterjee Shu-ching Chen Distributed Multimedia Information System Laboratory School of Computing and Information Sciences Florida International University Miami FL USA

ISBN: (纸本)0769527469;9780769527468

A novel indexing and access method, called affinity hybrid tree (AH-tree), is proposed to organize large image data sets efficiently and to support popular image access mechanisms like content-based image retrieval (CBIR) by embedding the high-level semantic image-relationship in the access mechanism as it is. AH-tree combines space-based and distance-based indexing techniques to form a hybrid structure which is efficient in terms of computational overhead and fairly accurate in producing query results close to human perception. algorithms for similarity (range and k-nearest neighbor) queries are implemented. Results from elaborate experiments are reported which depict a low computational overhead in terms of the number of I/O and distance computations and a high relevance of query results. The proposed index structure solves the existing problems of introducing high-level image relationships in a retrieval mechanism without going through the pain of translating the content-similarity measurement into feature-level equivalence and yet maintaining an efficient structure to organize the large sets of images

关键词： Indexing Information retrieval Image retrieval content based retrieval multimedia databases multimedia systems Multidimensional systems Indexes Image databases multimedia computing

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