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

We conduct cross-layer analysis to demonstrate that impairment-aware scheduling is ineffective in compensating the Q-factor degradation impact on all-optical routers based on arrayed waveguide gratings (AWGs) and fiber delay lines (FDLs).

The practical limit to impairment-aware scheduling in all-optical routers

Node churn can have a severe impact on the performance of P2P applications. In this paper, we consider the design of reliable P2P networks that can provide predictable performance. We exploit the experimental finding that the age of a node can be a reliable predictor of longer residual lifetime to develop mechanisms that organize the network around these more reliable nodes. We propose two protocols, TrebleCast and TrebleCast?, to implement reliable overlay networks. These protocols dynamically create reliable layers of peers by moving nodes with higher expected lifetime to the center of the overlay. These more reliable layers can then be called upon to deliver predictable performance in the presence of churn.

Reliable P2P networks: TrebleCast and TrebleCast

The articles in this special section focus on the growing market for electric vehicles, with an emphasis on vehicle-to-grid network (V2G) development. These articles explore the state of the art in research and development on V2G networks. From the perspective of the power-sector, V2G networks necessitate a careful management of charging/discharging services for a large population of EVs, with the objectives of guaranteeing grid stability, improving energy utilization, and reaping potential arbitrage value. In addition, as indispensable bridges for managing the large number of EVs connected to the power grid and their associated bi-directional energy-flows, new sophisticated designs for communication infrastructures and protocols will play a crucial role. The objective here is to realize an efficient and effective information-flow, in addition to the energy-flow, which enables real-time monitoring, signaling and information-dissemination in V2G networks, regardless of the location, time, and the physical conditions/types of EVs. Such designs require the integration of emerging advances in information, computing, and communications technologies. Therefore, V2G networks involve the multidisciplinary study of smart grids, communication networks, and transportation networks, and they will lead to a wide range of interesting studies of practical importance and theoretical impact.

Vehicle-to-grid networks

We examine the packet loss performance of scalable all-optical routers exploiting fiber delay lines, under non-uniform and bursty data center traffic conditions. Our analysis reveals that a load balancing stage, capable of evenly distributing the incoming traffic in both space and time, is indispensable in wavelength-routing data centers with a distributed-buffer architecture.

Load balancing in wavelength-routing cloud data centers

Asynchronous Transfer Mode (ATM) is the recommended transport technique for the Broadband ISDN by CCITT (I121) Many switches have been proposed to accommodate the ATM that requires fast packet switching capability [1-8] The proposed switches for the Broadband ISDN can be cLassified as input queueing or output queueing type The input queueing type have a throughput performance which is approximately 58 percent that of the output queueing type [1] However, output queueing networks require larger amounts of hardware than input queueing networks [2] In this paper, we propose a new multistage switch with internal buffering that approaches a maximum throughput of 100% as the buffering is increased The switch is capable of broadcasting and self-routing It consists of two switching planes which consist of packet processors, 2x2 switching elements, distributors and buffers located between stages and in the output ports The internal data rate of the proposed switch is the same as that of the arriving information stream In this sense, the switch does not require speedup The switch has Iog2 N stages that forward packets in store-and-forward fashion, thus incurring a latency of log2 N time periods Performance analysis shows additional delay is small

Alberto Leon-Garcia

Papers

The practical limit to impairment-aware scheduling in all-optical routers

Reliable P2P networks: TrebleCast and TrebleCast

Vehicle-to-grid networks

Load balancing in wavelength-routing cloud data centers

A multistage atm switch with interstage buffer