Copyright protection for the electronic distribution of text documents

Each copy of a text document can be made different in a nearly invisible way by repositioning or modifying the appearance of different elements of text, i.e., lines, words, or characters. A unique copy can be registered with its recipient, so that subsequent unauthorized copies that are retrieved can be traced back to the original owner. In this paper we describe and compare several mechanisms for marking documents and several other mechanisms for decoding the marks after documents have been subjected to common types of distortion. The marks are intended to protect documents of limited value that are owned by individuals who would rather possess a legal than an illegal copy if they can be distinguished. We will describe attacks that remove the marks and countermeasures to those attacks. An architecture is described for distributing a large number of copies without burdening the publisher with creating and transmitting the unique documents. The architecture also allows the publisher to determine the identity of a recipient who has illegally redistributed the document, without compromising the privacy of individuals who are not operating illegally. Two experimental systems are described. One was used to distribute an issue of the IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, and the second was used to mark copies of company private memoranda

Electronic marking and identification techniques to discourage document copying

Modern computer networks make it possible to distribute documents quickly and economically by electronic means rather than by conventional paper means. However, the widespread adoption of electronic distribution of copyrighted material is currently impeded by the ease of illicit copying and dissemination. In this paper we propose techniques that discourage illicit distribution by embedding each document with a unique codeword. Our encoding techniques are indiscernible by readers, yet enable us to identify the sanctioned recipient of a document by examination of a recovered document. We propose three coding methods, describe one in detail, and present experimental results showing that our identification techniques are highly reliable, even after documents have been photocopied

Anonymous credit card transactions

Techniques for performing credit-card transactions without disclosing the subject matter of the transaction to the institution providing the credit card. The techniques include the use of a communications exchange so that information and funds may be transferred without the destination for the transfer knowing the source of the information or funds and the use of public key encryption so that each party to the transaction and the communications exchange can read only the information the party or the exchange needs for its role in the transaction. Also disclosed are techniques for authenticating a card holder by receiving personal information from the card holder, using the information to ask the card holder one or more questions, and using the answers to authenticate the card holder

The Minimum Shared Edges Problem on Grid-like Graphs

We study the NP-hard Minimum Shared Edges (MSE) problem on graphs: decide whether it is possible to route $p$ paths from a start vertex to a target vertex in a given graph while using at most $k$ edges more than once. We show that MSE can be decided on bounded (i.e. finite) grids in linear time when both dimensions are either small or large compared to the number $p$ of paths. On the contrary, we show that MSE remains NP-hard on subgraphs of bounded grids. Finally, we study MSE from a parametrised complexity point of view. It is known that MSE is fixed-parameter tractable with respect to the number $p$ of paths. We show that, under standard complexity-theoretical assumptions, the problem parametrised by the combined parameter $k$, $p$, maximum degree, diameter, and treewidth does not admit a polynomial-size problem kernel, even when restricted to planar graphs

Natural Variation in the Vertical Distribution of Macrobenthic Invertebrates Within Sandy-Mud Habitats

Virginia Institute of Marine ScienceMaster of Science (M.Sc.

An Adaptive Intraframe DPCM Codec based Upon Nonstationary Image Model

This Paper Introduces a Nonstationary Model for Images and Develops an Adaptive Intrafield Dpcm Codec based Upon the Model. the Codec Attempts to Minimize the Mean‐square Coding Error at Each Sample Point in the Picture. the Quantizer in the Resulting Adaptive Codec is Found to Be Similar to that Previously Obtained from Visual Masking Considerations. Comparative Simulation Results using 256 X 256 Pixel Rasters Are Given for Two‐ and Three‐bit/pixel Versions of the Adaptive Codec, the Three‐bit/pixel Graham Codec, and Three‐bit/pixel Previous Element Dpcm. © 1979 the Bell System Technical Journa

Reduction of Transmission Error Propagation in Adaptively Predicted, DPCM Encoded Pictures

A New Technique for Reducing Transmission Error Propagation in Adaptively Predicted, dpcm‐encoded Pictures is Described. the Basis for the Technique is a Generalization of the Notion of Predictor Output Attenuation, Described by Graham, to Include Attenuation of the Adaptive Prediction Function. Simulation Results Are Presented that Show that Application of the Technique to Graham\u27s Codec Results in Significant Reduction in Error Propagation Without Degradation of Picture Quality. the Technique Requires No Increase in Transmission Rate. © 1979 the Bell System Technical Journa

Wavelength-routed networks with lightpath data interchanges

We observe that tunable wavelength converters (TWCs) that are traditionally installed in wavelength-routed (WR) networks for wavelength contention resolution can be further utilized to provide fast data switching between lightpaths. This allows us to route a data unit through a sequence of lightpaths from source to destination if a direct single lightpath connection is not available or if we want to minimize the overhead of setting up new lightpaths. Since TWCs have a tuning time of picoseconds, it may be possible to use the installed TWCs as lightpath data interchanges (LPIs) to improve the performance of WR networks without significant optical hardware upgrade. Compared with the multihop electronic grooming approach of lightpath networks, the LPI approach has a simpler WR node architecture, does not need expensive high-speed electrical multiplexers/routers, and does not sacrifice the bit-rate/format transparency of data between the source and destination. Our simulation results show that WR networks with LPIs can have much lower blocking probability than WR networks without LPIs if the traffic duration is short. We show that LPIs can also be used to provide new data transportation services such as optical time division multiplexing access (OTDMA) time-slotted service in WR networks. © 2010 OSA.published_or_final_versio

The Fair Distribution of Power to Electric Vehicles: An Alternative to Pricing

As the popularity of electric vehicles increases, the demand for more power can increase more rapidly than our ability to install additional generating capacity. In the long term we expect that the supply and demand will become balanced. However, in the interim the rate at which electric vehicles can be deployed will depend on our ability to charge these vehicles without inconveniencing their owners. In this paper, we investigate using fairness mechanisms to distribute power to electric vehicles on a smart grid. We assume that during peak demand there is insufficient power to charge all the vehicles simultaneously. In each five minute interval of time we select a subset of the vehicles to charge, based upon information about the vehicles. We evaluate the selection mechanisms using published data on the current demand for electric power as a function of time of day, current driving habits for commuting, and the current rates at which electric vehicles can be charged on home outlets. We found that conventional selection strategies, such as first-come-first-served or round robin, may delay a significant fraction of the vehicles by more than two hours, even when the total available power over the course of a day is two or three times the power required by the vehicles. However, a selection mechanism that minimizes the maximum delay can reduce the delays to a few minutes, even when the capacity available for charging electric vehicles exceeds their requirements by as little as 5%.Comment: accepted in IEEE Smartgridcomm'1