932967
Modulation and Information Hiding in Images
We use concepts from communication theory to characterize information hiding schemes: the amount of information that can be hidden, its perceptibility, and its robustness to removal can be modeled using the quantities channel capacity, signal-to-noise ratio, and jamming margin. We then introduce new information hiding schemes whose parameters can easily be adjusted to trade off capacity, imperceptibility, and robustness as required in the application. The theory indicates the most aggressive feasible parameter settings. We also introduce a technique called predistortion for increasing resistance to JPEG compression. Analogous tactics are presumably possible whenever a model of anticipated distortion is available.
5213007
Applying electric field sensing to human-computer interfaces
A non-contact sensor based on the interaction of a person with electric fields for human-computer interface is investigated. Two sensing modes are explored: an external electric field shunted to ground through a human body, and an external electric field transmitted through a human body to stationary receivers. The sensors are low power (milliwatts), high resolution (millimeter) low cost (a few dollars per channel), have low latency (millisecond), high update rate (1 kHz), high immunity to noise (>72 dB), are not affected by clothing, surface texture or reflectivity, and can operate on length scales from microns to meters. Systems incorporating the sensors include a finger mouse, a room that knows the location of its occupant, and people-sensing furniture. Haptic feedback using passive materials is described. Also discussed are empirical and analytical approaches to transform sensor measurements into position information.
14619787
Field Mice: Extracting Hand Geometry from Electric Field Measurements
Several members of a family of techniques called Electric Field Sensing are described. Each sensing technique can be understood as a measurement of the value of a different component in an effective circuit diagram that summarizes all possible current pathways involving the body to be sensed and the sensing electrodes. An analytical model of the sensor response is presented, and then a probabilistic framework for inferring geometrical information from field measurements is described. The inference framework is demonstrated for the cases of a two-dimensional and a three-dimensional mouse.
7878072
Imperceptible Sensory Channels
System designers can use imperceptible sensory channels to create smarter, safer, and more secure environments. Beyond their diverse applications, imperceptible sensory channels suggest a new approach to the problem of machine perception. In adapting a video camera a device designed to capture human-readable images for use by the PDP-6, Minsky and Papert had to match perceptual algorithms to the sensor's capabilities. In contrast, for sensory channels such as electric field imaging that have no human analog, the sensor hardware can be designed to support perceptual algorithms.
17082505
Designing Biomorphs with an Interactive Genetic Algorithm
We describe an interactive version of the Genetic Algorithm which can be used to evolve Fourier series based \biomorphs." The user plays the role of a binary-valued objective function. The usual Genetic operators of Selection, Mutation, and Crossover are applied normally. We discuss the Interactive Genetic Algorithm's use as a teaching tool and in domains in which measures of utility are di cult or impossible to specify mathematically. We argue that the evolution of biomorphs can be considered an ergonomic design problem, and with the evolution of biomorphs as an example, we argue that a large class of design problems can be cast as \imprecise optimization" and \solved" with Interactive Genetic Algorithms. Thus IGAs can be used for applications that fall somewhere between AI, optimization, and CAD.
17924974
Towards effective practitioner evaluation: an exploration of issues relating to skills, motivation and evidence
Although academics are increasingly expected to undertake studies of their practice, particularly where this involves the use of learning technology, experience to date suggests that meeting this expectation has proved difficult. This paper attempts to explain this difficulty. After reviewing literature that provides a rationale for practitioner evaluation, the experiences of three projects (EFFECTS, ASTER and SoURCE) which attempted to draw on this process are described. Three main areas of difficulty are discussed: the skills and motivations of the academics involved, and the kinds of evidence (and its analysis) that ‘count’ for a given evaluation. This discussion leads to the identification of a number of problems that inhibit practitioner evaluation, including ambiguity in the nature and purpose of evaluation, and a general feeling that the function of evaluation has already been served through existing quality mechanisms. Finally, the possible implications are considered of some or all of the steps in the evaluation process being undertaken by an evaluator working alongside the academic.
32676071
Exploring semantic dependencies for scalable concept detection
Semantic concept detection from multimedia features enables high-level access to multimedia content. While constructing robust detectors is feasible for concepts with sufficient training samples, concepts with fewer training samples are hard to train efficiently. Comparable performance may be possible if the dependence of these concepts on the ones that can be robustly modeled is exploited. In this paper we show this phenomenon using the TREC Video 2002 Corpus as a test bed. Using a basic set of 12 semantic concepts modeled with support vector machines, we predict presence of 4 other concepts. We then compare the performance of these predictors with direct SVM models for these 4 concepts and observe improvements of up to 150% in average precision.
16182080
Self adaptation of mutation rates in a steady state genetic algorithm
This paper investigates the use of genetically encoded mutation rates within a "steady state" genetic algorithm in order to provide a self-adapting mutation mechanism for incremental evolution. One of the outcomes of this work will be a reduction in the number of parameters required to be set by the operator, thus facilitating the transfer of evolutionary computing techniques into an industrial setting. The NK family of landscapes is used to provide a variety of different problems with known statistical features in order to examine the effects of changing various parameters on the performance of the search. A number of policies are considered for the replacement of members of the population with newly created individuals and recombination of material between parents, and a number of methods of encoding for mutation rate are investigated. Empirical comparisons (using the "best-of current-population" metric) over a range of test problems show that a genetic algorithm incorporating the best "flavour" of the adaptive mutation operator outperformed the same algorithm when using any one of a variety of "standard" fixed mutation rates suggested by other authors.
18087423
Image and video search engine for the World Wide Web
We describe a visual information system prototype for searching for images and videos on the World-Wide Web. New visual information in the form of images, graphics, animations and videos is being published on the Web at an incredible rate. However, cataloging this visual data is beyond the capabilities of current text-based Web search engines. In this paper, we describe a complete system by which visual information on the Web is (1) collected by automated agents, (2) processed in both text and visual feature domains, (3) catalogued and (4) indexed for fast search and retrieval. We introduce an image and video search engine which utilizes both text-based navigation and content-based technology for searching visually through the catalogued images and videos. Finally, we provide an initial evaluation based upon the cataloging of over one half million images and videos collected from the Web.
5110411
Quasigroups and quandles
Abstract Two connexions between quasigroups and quandles are established. In one direction, Joyce's homogeneous quandle construction is shown to yield a quasigroup isotopic to the loop constructed by Scimemi on the set of o-commutators of a group automorphism o. In the other direction, the universal multiplication group construction of quasigroup theory is extended to quandles. The group of a knot becomes the universal right multiplication group of the knot quandle.