In this paper we study the problem of jointly performing scheduling and congestion control in mobile adhoc networks so that network queues remain bounded and the resulting flow rates satisfy an associated network utility maximization problem. In recent years a number of papers have presented theoretical solutions to this problem that are based on combining differential-backlog scheduling algorithms with utility-based congestion control. However, this work typically does not address a number of issues such as how signaling should be performed and how the new algorithms interact with other wireless protocols.In this paper we address such issues. In particular:• We define a specific network utility maximization problem that we believe is appropriate for mobile adhoc networks. • We describe a wireless Greedy Primal Dual(wGPD) algorithm for combined congestion control and scheduling that aims to solve this problem. • We show how the wGPD algorithm and its associated signaling can be implemented in practice with minimal disruption to existing wireless protocols. • We show via OPNET simulation that wGPD significantly outperforms standard protocols such as 802.11 operating in conjunction with TCP.This work was supported by the DARPA CBMANET program.This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the IEEE INFOCOM 2008 proceedings. 978-1-4244-2026-1/08/$25.00

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Proper display and accurate recognition of document images are often hampered by degradations caused by poor scanning or transmission conditions. We propose a method to enhance such degraded document images for better display quality and recognition accuracy. The essence of the method is in finding and averaging bitmaps of the same symbol that are scattered across a text page. Outline descriptions of the symbols are then obtained that can be rendered at arbitrary resolution. The paper describes details of the algorithm and an experiment to demonstrate its capabilities using fax images.

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We present a system of interpolating splines with first-order and approximate second-order geometric continuity. The curves are easily computed in linear time by solving a diagonally dominant, tridiagonal system of linear equations. Emphasis is placed on the need to find aesthetically pleasing curves in a wide range of circumstances; favorable results are obtained even when the knots are very unequally spaced or widely separated. The curves are invariant under translation, rotation, and scaling, and the effects of a local change fall off exponentially as one moves away from the disturbed knot.Approximate second-order continuity is achieved by using a linear "mock curvature" function in place of the actual endpoint curvature for each spline segment and choosing tangent directions at knots so as to equalize these. This avoids extraneous solutions and other forms of undesirable behavior without seriously compromising the quality of the results.The actual spline segments can come from any family of curves whose endpoint curvatures can be suitably approximated, but we propose a specific family of parametric cubics. There is freedom to allow tangent directions and "tension" parameters to be specified at knots, and special "curl" parameters may be given for additional control near the endpoints of open curves.

This work explains how to analyze the aggregate electricity consumption of many consumers, and extract key components such as heating, ventilation and air conditioning (HVAC), residential lighting, and street lighting consumption from the total consumption. To avoid explicit modeling of dependencies on time of day and on working versus non-working days, leastsquares fitting for outside temperature and natural illumination dependency proceeds independently for each hour of the day. Cubic polynomials model dependencies on Steadman apparent temperature and on log-scale illumination, but spline surfaces are best when considering these variables jointly. The primary focus is on residential consumption, but the same techniques can be used for studying street lighting, commercial and industrial consumption.

Consider the problem of generating bitmaps from character shapes given as outlines. The obvious scan-conversion process does not produce acceptable results unless important features such as stem widths are carefully controlled during the scan-conversion process. This paper describes a method for automatically extracting the necessary feature information and generating high-quality bitmaps without resorting to hand editing. Almost all of the work is done in a preprocessing step, the result of which is an intermediate form that can be quickly converted into bitmaps once the font size and device resolution are known. A heuristically defined system of linear equations describes how the ideal outlines should be distorted in order to produce the best possible results when scan converted in a straightforward manner. The Lova´sz basis reduction algorithm then reduces the system of equations to a form that makes it easy to find an approximate solution subject to the constraint that some variables must be integers. The heuristic information is of such a general nature that it applies equally well to Roman fonts and Japanese Kanji.