13854955
Modeling Interactive Web Sources for Information Mediation
We propose a method for modeling complex Web sources that have active user interaction requirements. Here "active" refers to the fact that certain information in these sources is only reachable through interactions like filling out forms or clicking on image maps. Typically, the former interaction can be automated by wrapper software (e.g., using parameterized urls or post commands) while the latter cannot and thus requires explicit user interaction. We propose a modeling technique for such interactive Web sources and the information they export, based on so-called interaction diagrams. The nodes of an interaction diagram model sources and their exported information, whereas edges model transitions and their interactions. The paths of a diagram correspond to sequences of interactions and allow to derive the various query capabilities of the source. Based on these, one can determine which queries sire supported by a source and derive query plans with minimal user interaction. This technique can be used offline to support design and implementation of wrappers, or at runtime when the mediator generates query plans against such sources.
28954888
Modeling shape and topology of 3D images of biological specimens
This paper presents an efficient way of representing the geometry and topology of 3D images of biological specimens derived from electron microscopy. A vector quantization algorithm is used in order to select a reduced set of interior points that best approximates the probability density function of the original volumetric data. Object's geometry and topology are obtained from the point set by the use of the alpha shapes theory.
9743987
Complex Visual Activity Recognition Using a Temporally Ordered Database
We propose using a temporally ordered database for complex visual activity recognition. We use a temporal precedence relation together with the assumption of fixed bounded temporal uncertainty of occurrence time of an atomic activity and comparatively large temporal extent of the complex activity. Under these conditions we identify the temporal structure of complex activities as a semiorder and design a database that has semiorder as its data model. A query algebra is then defined for this data model.
8323337
Modeling Functional Data Sources as Relations
In this paper we present a model of functional access to data that, we argue, is suitable for modeling a class of data repositories characterized by functional access, such as web sites. We discuss the problem of modeling such data sources as a set of relations, of determining whether a given query expressed on these relations can be translated into a combination of functions defined by the data sources, and of finding an optimal plan to do so.
2635468
A System for Managing Alternate Models in Model-Based Mediation
In [1,3], we have described the problem of model-based mediation (MBM) as an extension of the global-as-view paradigm of information integration. The need for this extension arises in many application domains where the information sources to be integrated not only differ in their export formats, data models, and query capabilities, but have widely different schema with very little overlap in attributes. In scientific applications, the information sources come from different subdisciplines, and despite their poorly overlapping schema, can be integrated because they capture different aspects of the same scientific objects or phenomena, and can be conceptually integrated due to scientific reasons. In the MBM paradigm, a “mediation engineer” consults with domain experts to explicitly model the “glue knowledge” using a set of facts and rules at the mediator. Integrated views are defined in MBM on top of the exported schemas from the information sources together with the glue knowledge source that ties them together. We have successfully applied the MBM technique to develop the KIND mediator or Neuroscience information sources [1]-[4]. To accomplish this, sources in the MBM framework export their conceptual models (CMs), consisting of the logical schema, domain constraints, and object contexts, i.e., formulas that relate their conceptual schema with the global domain knowledge maintained at the mediator. Thus model-based mediation has a hybrid approach to information integration - on the one hand at the mediator integrated views are defined over source CMs and the Knowledge Map using a global-as-view approach; on the other hand, object-contexts of the source are defined as local-as-view.
14666453
An Interpolated Volume Data Model
Publisher Summary This chapter explores the basic functionality of the volume data model. It considers examples from biology and volumes of measurement from quantum physics. The data model is similar in the two cases, but the operations that are commonly used are quite different. In the second case, for instance, one is often interested in conditions on the behavior of local differential operators, such as zero-flow surfaces, while in the biological case one has a mix of value conditions and geometric condition. With these two application fields, this chapter highlights the generality and flexibility of the model. The system is based on a commercial database, augmented with specialized functions to manipulate the volume data model. The chapter demonstrates various operations specifying queries both using a graphical user interface and entering them directly in structured query language (SQL) augmented with the volume algebra operations.
44473002
Symmetry Reduction in SAT-Based Model Checking
The major challenge facing model checking is the state explosion problem. One technique to alleviate this is to apply symmetry reduction; this exploits the fact that many sequential systems consist of interchangeable components, and thus it may suffice to search a reduced version of the symmetric state space. Symmetry reduction has been shown to be an effective technique in both explicit and symbolic model checking with Binary Decision Diagrams (BDDs). In recent years, SAT-based model checking has been shown to be a promising alternative to BDD-based model checking. In this paper, we describe a symmetry reduction algorithm for SAT-based unbounded model checking (UMC) using circuit cofactoring. Our method differs from the previous efforts in using symmetry mainly in that we do not require converting any set of states to its representative or orbit set of states except for the set of initial states. This leads to significant simplicity in the implementation of symmetry reduction in model checking. Experimental results show that using our symmetry reduction approach improves the performance of SAT-based UMC due to both the reduced state space and simplification in the resulting SAT problems.
5958805
Selective and authentic third-party distribution of XML documents
Third-party architectures for data publishing over the Internet today are receiving growing attention, due to their scalability properties and to the ability of efficiently managing large number of subjects and great amount of data. In a third-party architecture, there is a distinction between the Owner and the Publisher of information. The Owner is the producer of information, whereas Publishers are responsible for managing (a portion of) the Owner information and for answering subject queries. A relevant issue in this architecture is how the Owner can ensure a secure and selective publishing of its data, even if the data are managed by a third-party, which can prune some of the nodes of the original document on the basis of subject queries and access control policies. An approach can be that of requiring the Publisher to be trusted with regard to the considered security properties. However, the serious drawback of this solution is that large Web-based systems cannot be easily verified to be secure and can be easily penetrated. For these reasons, we propose an alternative approach, based on the use of digital signature techniques, which does not require the Publisher to be trusted. The security properties we consider are authenticity and completeness of a query response, where completeness is intended with regard to the access control policies stated by the information Owner. In particular, we show that, by embedding in the query response one digital signature generated by the Owner and some hash values, a subject is able to locally verify the authenticity of a query response. Moreover, we present an approach that, for a wide range of queries, allows a subject to verify the completeness of query results.
12034549
On embedding ternary trees into Boolean hypercubes
It is pointed out that the problem of efficiently embedding a k-ary tree into hypercube with k>or=3 has largely remained unsolved, even though optimal embeddings (i.e. embeddings achieving minimum delta , lambda , and in ) of complete and incomplete binary trees into hypercubes have been known for some time. Thus, in their quest for designing efficient embeddings of k-ary trees into hypercube for arbitrary k, the authors present some preliminary results that give efficient embeddings for the situations when k=3, 2/sup p/, 3/sup p/, 2/sup p/*3/sup q/ and p, q>0. The embedding of complete ternary trees and the embedding of complete k-ary trees are considered.<<ETX>>
13293366
Improved bandwidth approximation for trees
A linear arrangement of an n-vertex graph G = (V, E) is a one-one mapping f of the vertex set V onto the set In] = {0, 1 , . . . , n 1}. The bandwidth of this linear arrangement is the maximum distance between the images of the endpoints of any edge in E(G). When the input graph G is a tree, the best known approximation algorithm for the minimum bandwidth linear arrangement (which is based on the principle of volume respecting embeddings) outputs a linear arrangement which has bandwidth within O(log 3 n) of the optimal bandwidth. In this paper, we present a simple randomized O(log 2 n lov~-n)-approximation algorithm for bandwidth minimization on trees.
8765967
A Dual-Pathway Neural Network Model of Control Relinquishment in Motor Skill Learning
Cognitive psychologists have long recognized that the acquisition of a motor skill involves a transition from attention-demanding controlled processing to more fluent automatic processing. Neuroscientific studies suggest that controlled and automatic processing rely on two largely distinct neural pathways. The controlled pathway, which includes the prefrontal cortex, is seen as acquiring declarative representations of skills. In comparison, the automatic pathway is thought to develop procedural representations. Automaticity in motor skill learning involves a reduction in dependence on frontal systems and an increased reliance on the automatic pathway. In this paper, we propose a biologically plausible computational model of motor skill automaticity. This model offers a dual-pathway neurocomputational account of the translation of declarative knowledge into procedural knowledge during motor learning. In support of the model, we review some previously reported human experimental results involving the learning of a sequential key pressing task, and we demonstrate, through simulation, howthe model provides a parsimonious explanation for these results.