Usually, a proof of a theorem contains more knowledge than the mere fact that the theorem is true. For instance, to prove that a graph is Hamiltonian it suffices to exhibit a Hamiltonian tour in it; however, this seems to contain more knowledge than the single bit Hamiltonian/non-Hamiltonian.In this paper a computational complexity theory of the “knowledge” contained in a proof is developed. Zero-knowledge proofs are defined as those proofs that convey no additional knowledge other than the correctness of the proposition in question. Examples of zero-knowledge proof systems are given for the languages of quadratic residuosity and 'quadratic nonresiduosity. These are the first examples of zero-knowledge proofs for languages not known to be efficiently recognizable.

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The knowledge complexity of interactive proof-systems

The development of the Internet in recent years has made it possible and useful to access many different information systems anywhere in the world to obtain information. While there is much research on the integration of heterogeneous information systems, most commercial systems stop short of the actual integration of available data. Data fusion is the process of fusing multiple records representing the same real-world object into a single, consistent, and clean representation.This article places data fusion into the greater context of data integration, precisely defines the goals of data fusion, namely, complete, concise, and consistent data, and highlights the challenges of data fusion, namely, uncertain and conflicting data values. We give an overview and classification of different ways of fusing data and present several techniques based on standard and advanced operators of the relational algebra and SQL. Finally, the article features a comprehensive survey of data integration systems from academia and industry, showing if and how data fusion is performed in each.

Data fusion

Computational geometry

Power Aware Routing in Mobile Ad Hoc Networks

This paper tackles a major privacy concern in current location-based services where users have to continuously report their locations to the database server in order to obtain the service. For example, a user asking about the nearest gas station has to report her exact location. With untrusted servers, reporting the location information may lead to several privacy threats. In this paper, we present Casper1; a new framework in which mobile and stationary users can entertain location-based services without revealing their location information. Casper consists of two main components, the location anonymizer and the privacy-aware query processor. The location anonymizer blurs the users' exact location information into cloaked spatial regions based on user-specified privacy requirements. The privacy-aware query processor is embedded inside the location-based database server in order to deal with the cloaked spatial areas rather than the exact location information. Experimental results show that Casper achieves high quality location-based services while providing anonymity for both data and queries.

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The new Casper: query processing for location services without compromising privacy

INTRODUCTION What is a GIS? GIS Functionality Data and Databases Hardware Support FUNDAMENTAL DATABASE CONCEPTS Introduction to Databases Relational Databases Database Development Object-Orientation FUNDAMENTAL SPATIAL CONCEPTS Euclidean Space Set-Based Geometry of Space Topology of Space Network Spaces Metric Spaces Endnote on Fractal Geometry MODELS OF GEOSPATIAL INFORMATION Modeling and Ontology The Modeling Process Field-Based Models Object-Based Models REPRESENTATION AND ALGORITHMS Computing with Geospatial Data The Discrete Euclidean Plane The Spatial Object Domain Representations of Field-Based Models Fundamental Geometric Algorithms Vectorization and Rasterization Network Representation and Algorithms STRUCTURES AND ACCESS METHODS General Database Structures and Access Methods From One to Two Dimensions Raster Structures Point Object Structures Linear Objects Collections of Objects Spherical Data Structures ARCHITECTURES Hybrid, Integrated, and Composable Architectures Syntactic and Semantic Heterogeneity Distributed Systems Distributed Databases Location-Aware Computing INTERFACES Human-Computer Interaction Cartographic Interfaces Geovisualization Developing GIS Interfaces SPATIAL REASONING AND UNCERTAINTY Formal Aspects of Spatial Reasoning Information and Uncertainty Qualitative Approaches to Uncertainty Quantitative Approaches to Uncertainty Applications of Uncertainty in GIS TIME Introduction: A Brief History of Time Temporal Information Systems Spatiotemporal Information Systems Indexes and Queries Appendices

GIS : a computing perspective

Obfuscation concerns the practice of deliberately degrading the quality of information in some way, so as to protect the privacy of the individual to whom that information refers. In this paper, we argue that obfuscation is an important technique for protecting an individual's location privacy within a pervasive computing environment. The paper sets out a formal framework within which obfuscated location-based services are defined. This framework provides a computationally efficient mechanism for balancing an individual's need for high-quality information services against that individual's need for location privacy. Negotiation is used to ensure that a location-based service provider receives only the information it needs to know in order to provide a service of satisfactory quality. The results of this work have implications for numerous applications of mobile and location-aware systems, as they provide a new theoretical foundation for addressing the privacy concerns that are acknowledged to be retarding the widespread acceptance and use of location-based services.

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A formal model of obfuscation and negotiation for location privacy

Cultural Studies.- Progress on Yindjibarndi Ethnophysiography.- Study of Cultural Impacts on Location Judgments in Eastern China.- Cross-Cultural Similarities in Topological Reasoning.- Thalassographein: Representing Maritime Spaces in Ancient Greece.- Semantics.- From Top-Level to Domain Ontologies: Ecosystem Classifications as a Case Study.- Semantic Categories Underlying the Meaning of 'Place'.- Spatial Semantics in Difference Spaces.- Similarity.- Evaluation of a Semantic Similarity Measure for Natural Language Spatial Relations.- Affordance-Based Similarity Measurement for Entity Types.- An Image-Schematic Account of Spatial Categories.- Mapping and Representation.- Specifying Essential Features of Street Networks.- Spatial Information Extraction for Cognitive Mapping with a Mobile Robot.- Spatial Mapping and Map Exploitation: A Bio-inspired Engineering Perspective.- Scale-Dependent Simplification of 3D Building Models Based on Cell Decomposition and Primitive Instancing.- Perception and Cognition.- Degradation in Spatial Knowledge Acquisition When Using Automatic Navigation Systems.- Stories as Route Descriptions.- Three Sampling Methods for Visibility Measures of Landscape Perception.- Reasoning and Algorithms.- Reasoning on Spatial Semantic Integrity Constraints.- Spatial Reasoning with a Hole.- Geospatial Cluster Tessellation Through the Complete Order-k Voronoi Diagrams.- Drawing a Figure in a Two-Dimensional Plane for a Qualitative Representation.- Navigation and Landmarks.- Linguistic and Nonlinguistic Turn Direction Concepts.- A Uniform Handling of Different Landmark Types in Route Directions.- Effects of Geometry, Landmarks and Orientation Strategies in the 'Drop-Off' Orientation Task.- Uncertainty and Imperfection.- Data Quality Ontology: An Ontology for Imperfect Knowledge.- Triangulation of Gradient Polygons: A Spatial Data Model for Categorical Fields.- Relations in Mathematical Morphology with Applications to Graphs and Rough Sets.

Spatial Information Theory

Geographic Information Science. The Nature and Value of Geographic Information. Communicating Geographic Information in Context. Pragmatic Information Content. Representational Commitment in Maps. Granularity in Change over Time. A Theory of Granular Partitions. On the Ontological Status of Geographical Boundaries. Regions in Geography. Neighborhoods and Landmarks. Geographical Terminology Servers. Placing Cultural Events and Documents. Geographic Activity Models.

Foundations of Geographic Information Science

Numerous cognitive studies have indicated that the form and complexity of route instructions may be as important to human navigators as the overall length of route. Most automated navigation systems rely on computing the solution to the shortest path problem, and not the problem of finding the “simplest” path. This paper addresses the issue of finding the “simplest” paths through a network, in terms of the instruction complexity. We propose a “simplest” paths algorithm that has quadratic computation time for a planar graph. An empirical study of the algorithm’s performance, based on an established cognitive model of navigation instruction complexity, revealed that the length of a simplest path was on average only 16% longer than the length of the corresponding shortest path. In return for marginally longer routes, the simplest path algorithm seems to offer considerable advantages over shortest paths in terms of their ease of description and execution. The conclusions indicate several areas for future research: in particular cognitive studies are needed to verify these initial computational results. Potentially, the simplest paths algorithm could be used to replace shortest paths algorithms in any automated system for generating human navigation instructions, including in-car navigation systems, Internet driving direction servers, and other location-based services.

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Matt Duckham

Papers

GIS : a computing perspective

A formal model of obfuscation and negotiation for location privacy

Spatial Information Theory

Foundations of Geographic Information Science

"Simplest" Paths: Automated Route Selection for Navigation