This paper addresses the issues of charging, rate control and routing for a communication network carrying elastic traffic, such as an ATM network offering an available bit rate service. A model is described from which max-min fairness of rates emerges as a limiting special case; more generally, the charges users are prepared to pay influence their allocated rates. In the preferred version of the model, a user chooses the charge per unit time that the user will pay; thereafter the user's rate is determined by the network according to a proportional fairness criterion applied to the rate per unit charge. A system optimum is achieved when users' choices of charges and the network's choice of allocated rates are in equilibrium.

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Charging and rate control for elastic traffic

This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

[서평]「Component Software」 - Beyond Object-Oriented Programming -

The Long Tail: How Technology is turning mass markets into millions of niches. (p. 15). This passage from The Long Tail, pretty much sums it all up. The Long Tail by Chris Anderson is a good and worthwhile read for information scientists, computer scientists, ecommerce researchers, and others interested in all areas of Web research. The central premise of the book is that the combination of (1) the Pareto or Zipf distribution (i.e., power law probability distribution) that is characteristic of Web traffic and (2) the direct access to consumers via Web technology has opened up new business opportunities in the ''long tail''. Producers and advertisers no longer have to target ''the big hits'' at the head of the distribution. Instead, they can target the small, niche communities or even individuals in the tail of the distribution. The long tail is has been studied by Web researchers and has been noted in term usage on search engines, access times to servers, and popularity of Web sites. Andersen points out that the long tail also applies to products sold on the Web. He recounts that a sizeable percentage of Amazon sales come from books that only sell a few copies, a large number of songs from Rhapsody get downloaded only once in a month, and a significant number of movies from Netflix only get ordered occasionally. However, since the storage is in digital form for the songs and music (and Amazon out sources the storage of books) there is little additional inventory cost of these items. This phenomenon across all Web companies has led to a broadening of participation by both producers and consumers that would not have happened without the Web. The idea of the long tail is well known, of course. What Anderson has done is present it in an interesting manner and in a Web ecommerce setting. He applies it to Web businesses and then relates the multitude of other factors ongoing that permit the actual implementation of the long tail effect. Anderson also expands on prior work on the long tail by introducing an element of time, given the distribution a three dimensional effect. All in all, it is a nifty idea. The book is comprised of 14 chapters, plus an Introduction. Chapter 1 presents an overview of what the long tail is. Chapter 2 discusses the ''head'', which is the top of the tail where the …

The Long Tail: Why the Future of Business is Selling Less of More

Many commercial video players rely on bitrate adaptation logic to adapt the bitrate in response to changing network conditions. Past measurement studies have identified issues with today's commercial players with respect to three key metrics---efficiency, fairness, and stability---when multiple bitrate-adaptive players share a bottleneck link. Unfortunately, our current understanding of why these effects occur and how they can be mitigated is quite limited.In this paper, we present a principled understanding of bitrate adaptation and analyze several commercial players through the lens of an abstract player model. Through this framework, we identify the root causes of several undesirable interactions that arise as a consequence of overlaying the video bitrate adaptation over HTTP. Building on these insights, we develop a suite of techniques that can systematically guide the tradeoffs between stability, fairness and efficiency and thus lead to a general framework for robust video adaptation. We pick one concrete instance from this design space and show that it significantly outperforms today's commercial players on all three key metrics across a range of experimental scenarios.

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Improving fairness, efficiency, and stability in HTTP-based adaptive video streaming with FESTIVE

The success of next-generation mobile communication systems depends on the ability of service providers to engineer new added-value multimedia-rich services, which impose stringent constraints on the underlying delivery/transport architecture. The reliability of real-time services is essential for the viability of any such service offering. The sporadic packet loss typical of wireless channels can be addressed using appropriate techniques such as the widely used packet-level forward error correction. In designing channel-aware media streaming applications, two interrelated and challenging issues should be tackled: accuracy of characterizing channel fluctuations and effectiveness of application-level adaptation. The first challenge requires thorough insight into channel fluctuations and their manifestations at the application level, while the second concerns the way those fluctuations are interpreted and dealt with by adaptive mechanisms such as FEC. In this article we review the major issues that arise when designing a reliable media streaming system for wireless networks.

Forward error correction strategies for media streaming over wireless networks

The need for higher frequency in state estimation execution covering larger supervised networks has led to the investigation of faster and numerically more stable state estimation algorithms. However, technical developments in distributed Energy Management Systems, based on fast data communication networks, open up the possibility of parallel or distributed state estimation implementation. In this paper, this possibility is exploited to derive a solution methodology based on conventional state estimation algorithms and a coupling constraints optimization technique. Numerical experiments show suitable performance of the proposed method with regard to estimation accuracy, convergence robustness and computational efficiency. The results of these experiments also indicate the decoupled nature of the state estimation problem. >

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Parallel and distributed state estimation

In general, video quality adaptation and video quality evaluation are distinct activities. Most adaptive delivery mechanisms for streaming multimedia content do not explicitly consider user-perceived quality when making adaptation decisions. Equally, video quality evaluation techniques are not designed to evaluate instantaneous quality where the quality is changing over time. We propose that an Optimal Adaptation Trajectory (OAT) through the set of possible encoding exists, and that it indicates how to adapt encoding quality in response to changes in network conditions in order to maximize user-perceived quality. The subjective and objective tests carried out to find such trajectories for a number of different MPEG-4 video clips are described. Experimental subjective testing results are presented that demonstrate the dynamic nature of user perception with adapting multimedia. The results demonstrate that adaptation using the OAT out-performs conventional adaptation strategies in which only a single aspect of the video quality is adapted. In contrast, the OAT provides a mechanism to adapt multiple aspects of the video quality thereby giving better user-perceived quality in both the short and long term.

User perception of adapting video quality

This article explores and connects two issues: (1) the relation between the Rule of Law (or legality) and the work we do in general jurisprudence on the concept of law; and (2) the distinction between conceptions of the Rule of Law that emphasize certainty, rules, and predictability and conceptions of the Rule of Law that also emphasize procedure and argument, even when legal argumentation detracts from the certainty emphasized the first set of conceptions. It argues (1) in favour of a more demanding understanding of what law is (informed by the ideal of the Rule of Law) and against "casual positivism" that takes almost any instance of centralized command and control as a legal system. And it argues (2) in favour of a procedural and argumentative conception of the Rule of Law. It connects the two arguments by observing that casual positivism is commonly associated with an impoverished rule-oriented understanding of the Rule of Law is associated commonly; and (following Dworkin and MacCormick) it suggests that a jurisprudence that emphasizes the role of legal argumentation and the institutions that sponsor it, will inevitably bring our conceptions of law and legality very close together.

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The Concept and the Rule of Law

A significant challenge in all-IP multi-service networks is to balance the goal of providing high-quality services to the end-users with the desire to maximize the number of end-users that can be simultaneously served. This paper presents a solution to this challenge by using the Quality-Oriented Adaptation Scheme (QOAS) for delivering multimedia streams. This adaptive mechanism uses feedback from clients regarding the quality of delivery to assist the server in making dynamic adjustments to the transmitted streams. Experimental objective and subjective test results illustrate the significant performance improvements achieved by QOAS, both in terms of number of simultaneous viewers served and of end-user perceived quality.

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Liam Murphy

Papers

Forward error correction strategies for media streaming over wireless networks

Parallel and distributed state estimation

User perception of adapting video quality

The Concept and the Rule of Law

A new adaptive multimedia streaming system for all-IP multi-service networks