We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

We propose a natural scene statistic-based distortion-generic blind/no-reference (NR) image quality assessment (IQA) model that operates in the spatial domain. The new model, dubbed blind/referenceless image spatial quality evaluator (BRISQUE) does not compute distortion-specific features, such as ringing, blur, or blocking, but instead uses scene statistics of locally normalized luminance coefficients to quantify possible losses of “naturalness” in the image due to the presence of distortions, thereby leading to a holistic measure of quality. The underlying features used derive from the empirical distribution of locally normalized luminances and products of locally normalized luminances under a spatial natural scene statistic model. No transformation to another coordinate frame (DCT, wavelet, etc.) is required, distinguishing it from prior NR IQA approaches. Despite its simplicity, we are able to show that BRISQUE is statistically better than the full-reference peak signal-to-noise ratio and the structural similarity index, and is highly competitive with respect to all present-day distortion-generic NR IQA algorithms. BRISQUE has very low computational complexity, making it well suited for real time applications. BRISQUE features may be used for distortion-identification as well. To illustrate a new practical application of BRISQUE, we describe how a nonblind image denoising algorithm can be augmented with BRISQUE in order to perform blind image denoising. Results show that BRISQUE augmentation leads to performance improvements over state-of-the-art methods. A software release of BRISQUE is available online: http://live.ece.utexas.edu/research/quality/BRISQUE_release.zip for public use and evaluation.

/pdf/no-reference-image-quality-assessment-in-the-spatial-domain-2mnlvf25ig.pdf

No-Reference Image Quality Assessment in the Spatial Domain

An important aim of research on the blind image quality assessment (IQA) problem is to devise perceptual models that can predict the quality of distorted images with as little prior knowledge of the images or their distortions as possible. Current state-of-the-art “general purpose” no reference (NR) IQA algorithms require knowledge about anticipated distortions in the form of training examples and corresponding human opinion scores. However we have recently derived a blind IQA model that only makes use of measurable deviations from statistical regularities observed in natural images, without training on human-rated distorted images, and, indeed without any exposure to distorted images. Thus, it is “completely blind.” The new IQA model, which we call the Natural Image Quality Evaluator (NIQE) is based on the construction of a “quality aware” collection of statistical features based on a simple and successful space domain natural scene statistic (NSS) model. These features are derived from a corpus of natural, undistorted images. Experimental results show that the new index delivers performance comparable to top performing NR IQA models that require training on large databases of human opinions of distorted images. A software release is available at http://live.ece.utexas.edu/research/quality/niqe_release.zip.

/pdf/making-a-completely-blind-image-quality-analyzer-4rsald8tn3.pdf

Making a “Completely Blind” Image Quality Analyzer

Over the past decade, there has been an explosion of interest in network research across the physical and social sciences. For social scientists, the theory of networks has been a gold mine, yielding explanations for social phenomena in a wide variety of disciplines from psychology to economics. Here, we review the kinds of things that social scientists have tried to explain using social network analysis and provide a nutshell description of the basic assumptions, goals, and explanatory mechanisms prevalent in the field. We hope to contribute to a dialogue among researchers from across the physical and social sciences who share a common interest in understanding the antecedents and consequences of network phenomena.

/pdf/network-analysis-in-the-social-sciences-440fzedv4c.pdf

Network Analysis in the Social Sciences

I. the origin of species by means of natural selection

The study of robustness and connectivity properties are important in the analysis of complex networks. This paper reports on an effort to compare different network topologies according to their algebraic connectivity, network criticality, average node degree, and average node betweenness. We consider different network types and study the behavior of these various metrics as scale is increased. Based on extensive simulations, we suggest some guidelines for the design and simplification of networks. The main finding is that, algebraic connectivity, network criticality, average degree, and average node betweenness capture different properties of a graph. Depending on the nature of the problem at hand, one needs to select which one is appropriate to use as the main metric for network analysis.

/pdf/comparison-of-network-criticality-algebraic-connectivity-and-3gs8ympb4p.pdf

Comparison of network criticality, algebraic connectivity, and other graph metrics

The next-generation network will enable provision of various multimedia applications, with different QoS requirements, over a common IP- based transport infrastructure. However, along with the service consolidation over IP and the rapid increase of network scale, the task of service and network management has become extremely complex and costly. Efforts are being made in various areas, for example, SOA, application-oriented networking, and autonomic computing, to achieve a scalable, secure, and self-managed service delivery framework to shorten the time-to-market of new Internet applications, as well as lower the management costs of service providers. Nevertheless, these technologies are not developed in a coordinated manner for optimal scalability, resource utilization, and QoS performance. In this article, we propose a prototype architecture and discuss related implementation issues for an autonomic service management framework, based on a holistic view of SOA, AON, and autonomic computing. In ASMF, a business or management application with end-to-end QoS requirements can be automatically composed from standard service components in a distributed manner and autonomically managed according to service level agreements.

/pdf/toward-an-autonomic-service-management-framework-a-holistic-4xg0b18252.pdf

Toward an Autonomic Service Management Framework: A Holistic Vision of SOA, AON, and Autonomic Computing

An output-buffered packet switch with priority packet transmission and a flexible buffer management scheme is disclosed. The switch consists of a sorting network at the input, a nonblocking routing network at the output, and multiple modules of column-fill networks together with the storage elements connected in series to provide a novel buffer management scheme. Each module provides one dedicated buffer for each output port, except the last module where the storage is shared by all the outputs. The combination of dedicated and shared buffering gives high performance for a wide range of traffic conditions. The switch is expandable in the sense that its performance can be enhanced by simply adding more modules. The switch design is distributed and has self-routing capabilities, so it can operate at very high data rates. The output-buffered packet switch can be used to implement a centralized control for another packet switch of higher speed but same functionality.

Output-buffered packet switch with a flexible buffer management scheme

Future wireless ATM networks are expected to support a variety of services with different bit-rates and quality-of-service (QoS) requirements. A major challenge for these networks is the design of the multiple access scheme. We introduce a new MAC protocol called scheduled CDMA (SCDMA). This scheme is a hybrid CDMA/TDMA scheme in which the base station schedules transmission of CDMA-based mobile terminals. At any time, a group of services are scheduled to transmit simultaneously. Interference control is done with power control. Several QoS issues of this scheme are addressed including power control, application of FEC coding, and high bit-rate service support.

Scheduled CDMA: a hybrid multiple access for wireless ATM networks

A method and system for integrated management of converged heterogeneous resources is disclosed. The method includes: defining a Software-Defined Infrastructure (SDI) by separating data, control, and management for converged heterogeneous resource provisioning, creating an integrated resource manager using interfaces for one or more cloud controllers, Software-Defined Network (SDN) controllers, or general-resource controllers, enabling external entities to request and use the resources through interfaces, storing topology information and utilizing it for integrated resource management, and monitoring and measuring the converged heterogeneous resources. An integrated management system includes an SDI manager configured to provide integrated resource control and management functions, a cloud controller, an SDN controller, a general resource controller, a topology manager, northbound interfaces of an SDI manager for external entities to request resources and check the status of resources, and all inter-relations between an SDI manager, a cloud controller, an SDN manager, a general resource manager and a topology manager.

Alberto Leon-Garcia

Papers

Comparison of network criticality, algebraic connectivity, and other graph metrics

Toward an Autonomic Service Management Framework: A Holistic Vision of SOA, AON, and Autonomic Computing

Output-buffered packet switch with a flexible buffer management scheme

Scheduled CDMA: a hybrid multiple access for wireless ATM networks

Method and System for Integrated Management of Converged Heterogeneous Resources in Software-Defined Infrastructure