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

Many modern day cloud services are composites of multiple smaller services working correctly together. This design has become increasingly prevalent due to the rise of the microservices application architecture, as well as service chaining in Network Function Virtualization (NFV). Future composite applications and services will be deployed on multi-tier clouds where their constituent microservices may be geographically spread over different regions. To optimize the delivery of such composites, the constituent microservices must be placed in locations where their clients, which may be other microservices, are able to meet certain QoS constraints. We propose an architecture and present a prototype system for incorporating network metrics into the auto-scaling and scheduling decisions of cloud management systems. Given a service with QoS constraints, our system monitors the network metrics (e.g. latency and bandwidth) of their clients. If a particular client is unable to receive the required latency or bandwidth of the service, our system auto-scales the service and strategically places the new instance(s) in a location capable of meeting the service quality, and re-directs traffic to the new instance.

Towards a Client-Centric QoS Auto-Scaling System

Towards a generic real-time transport and adaptation protocol for IP networks

An approach to the delay analysis of various service disciplines in symmetric token passing networks is presented. It is shown that exact or approximate accurate expressions for the average packet delay of different service disciplines can be directly derived by the delay expression of the exhaustive service system. This can be accomplished by inflating, by an appropriate factor, the packet size of the discipline whose performance is analyzed and then using the inflated packet in the delay expression of the exhaustive service system. The method is applied to the analysis of the limited service and TTS disciplines, and its accuracy is verified by simulation results. The advantages of the analytic method presented are its generality, higher accuracy over previous analytic methods, and insensitivity to network latency and other system parameters. >

Delay analysis of various service disciplines in symmetric token passing networks

Peer-to-Peer (P2P) systems have witnessed an explosive growth in popularity due to their desirable characteristics (robustness, scalability, availability). In this paper, we present an approach to bring these characteristics into the control plane of IP networks, which mainly relies on signaling protocols such as SIP to setup multimedia and instant messaging sessions. We present a structured P2P control plane based on modifications to the original Chord P2P topology, resulting in a hierarchical overlay of SIP peers that replaces traditional client-server paradigms in control plane signaling protocols. Implementations were used to study the performance of the proposed structured P2P control plane, and its suitability for use in IP networks.

/pdf/structured-peer-to-peer-control-plane-4rfi449vd8.pdf

Structured Peer-to-Peer Control Plane

We begin by considering the grand challenge to design application platforms that will enable the smart city. We identify two fundamental research challenges: 1. Cross-infrastructure Management Systems to coordinate resource use in a city; 2. Services Platforms that promote collective and individual intelligence. Next we report research progress in the design of application platforms that can support the smart applications required in the smart city. In particular, we describe the SAVI (Smart Applications on Virtual Infrastructure) application platform testbed for research in smart applications and its design using software-defined infrastructure. We present the CVST (Connected Vehicles and Smart Transportation) Platform for Intelligent Transportation Services in the Greater Toronto area, which runs on the SAVI testbed. Its design provides the intelligence to enable smart management in smart cities. We end with a discussion of general principles for the design of smart infrastructures.

Alberto Leon-Garcia

Papers

Towards a Client-Centric QoS Auto-Scaling System

Towards a generic real-time transport and adaptation protocol for IP networks

Delay analysis of various service disciplines in symmetric token passing networks

Structured Peer-to-Peer Control Plane

Application platforms for smart cities