Scalable Statistical Modeling and Query Processing over Large Scale Uncertain Databases

The past decade has witnessed a large number of novel applications that generate imprecise, uncertain and incomplete data. Examples include monitoring infrastructures such as RFIDs, sensor networks and web-based applications such as information extraction, data integration, social networking and so on. In my dissertation, I addressed several challenges in managing such data and developed algorithms for efficiently executing queries over large volumes of such data. Specifically, I focused on the following challenges. First, for meaningful analysis of such data, we need the ability to remove noise and infer useful information from uncertain data. To address this challenge, I first developed a declarative system for applying dynamic probabilistic models to databases and data streams. The output of such probabilistic modeling is probabilistic data, i.e., data annotated with probabilities of correctness/existence. Often, the data also exhibits strong correlations. Although there is prior work in managing and querying such probabilistic data using probabilistic databases, those approaches largely assume independence and cannot handle probabilistic data with rich correlation structures. Hence, I built a probabilistic database system that can manage large-scale correlations and developed algorithms for efficient query evaluation. Our system allows users to provide uncertain data as input and to specify arbitrary correlations among the entries in the database. In the back end, we represent correlations as a forest of junction trees, an alternative representation for probabilistic graphical models (PGM). We execute queries over the probabilistic database by transforming them into message passing algorithms (inference) over the junction tree. However, traditional algorithms over junction trees typically require accessing the entire tree, even for small queries. Hence, I developed an index data structure over the junction tree called INDSEP that allows us to circumvent this process and thereby scalably evaluate inference queries, aggregation queries and SQL queries over the probabilistic database. Finally, query evaluation in probabilistic databases typically returns output tuples along with their probability values. However, the existing query evaluation model provides very little intuition to the users: for instance, a user might want to know Why is this tuple in my result? or Why does this output tuple have such high probability? or Which are the most influential input tuples for my query ?'' Hence, I designed a query evaluation model, and a suite of algorithms, that provide users with explanations for query results, and enable users to perform sensitivity analysis to better understand the query results

Workshop on Database Programming Languages

These are the revised proceedings of the Workshop on Database Programming Languages held at Roscoff, Finistère, France in September of 1987. The last few years have seen an enormous activity in the development of new programming languages and new programming environments for databases. The purpose of the workshop was to bring together researchers from both databases and programming languages to discuss recent developments in the two areas in the hope of overcoming some of the obstacles that appear to prevent the construction of a uniform database programming environment. The workshop, which follows a previous workshop held in Appin, Scotland in 1985, was extremely successful. The organizers were delighted with both the quality and volume of the submissions for this meeting, and it was regrettable that more papers could not be accepted. Both the stimulating discussions and the excellent food and scenery of the Brittany coast made the meeting thoroughly enjoyable. There were three main foci for this workshop: the type systems suitable for databases (especially object-oriented and complex-object databases,) the representation and manipulation of persistent structures, and extensions to deductive databases that allow for more general and flexible programming. Many of the papers describe recent results, or work in progress, and are indicative of the latest research trends in database programming languages. The organizers are extremely grateful for the financial support given by CRAI (Italy), Altaïr (France) and AT&T (USA). We would also like to acknowledge the organizational help provided by Florence Deshors, Hélène Gans and Pauline Turcaud of Altaïr, and by Karen Carter of the University of Pennsylvania

Proceedings of the 21st Conference on Formal Methods in Computer-Aided Design – FMCAD 2021

The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing

Pseudo-contractions as Gentle Repairs

Updating a knowledge base to remove an unwanted consequence is a challenging task. Some of the original sentences must be either deleted or weakened in such a way that the sentence to be removed is no longer entailed by the resulting set. On the other hand, it is desirable that the existing knowledge be preserved as much as possible, minimising the loss of information. Several approaches to this problem can be found in the literature. In particular, when the knowledge is represented by an ontology, two different families of frameworks have been developed in the literature in the past decades with numerous ideas in common but with little interaction between the communities: applications of AGM-like Belief Change and justification-based Ontology Repair. In this paper, we investigate the relationship between pseudo-contraction operations and gentle repairs. Both aim to avoid the complete deletion of sentences when replacing them with weaker versions is enough to prevent the entailment of the unwanted formula. We show the correspondence between concepts on both sides and investigate under which conditions they are equivalent. Furthermore, we propose a unified notation for the two approaches, which might contribute to the integration of the two areas

Kiel Declarative Programming Days 2013

This report contains the papers presented at the Kiel Declarative Programming Days 2013, held in Kiel (Germany) during September 11-13, 2013. The Kiel Declarative Programming Days 2013 unified the following events: * 20th International Conference on Applications of Declarative Programming and Knowledge Management (INAP 2013) * 22nd International Workshop on Functional and (Constraint) Logic Programming (WFLP 2013) * 27th Workshop on Logic Programming (WLP 2013) All these events are centered around declarative programming, an advanced paradigm for the modeling and solving of complex problems. These specification and implementation methods attracted increasing attention over the last decades, e.g., in the domains of databases and natural language processing, for modeling and processing combinatorial problems, and for high-level programming of complex, in particular, knowledge-based systems

Principles of logic design

This study involves logic design and switching theory, in particular their practical application to the logic design and understanding of digital machines. Digital machines, of course, play an extremely important role in that large class of machines known as digital computers. But they also play an important role in many other kinds of practical devices important in the design of communications systems, digital control systems, counters, registers, digital meters, and so on. The basic content of switching theory is very simple. It embodies that body of machines and machine behavior that can be realized with "switches", things that are either "on" or "off", and nothing, really, could be much simpler than that. Of course the world is really comprised of very many complex structures which are really composed of exceedingly simple lesser structures, so that we really shouldn't be too surprised that even though the elements of switching theory are quite simple, their consequences are not necessarily so. The goals of our study are several, and include at least the following: 1) to develop some understanding and capability in using the techniques, design procedures, and models that have been developed for understanding and designing digital networks; 2) to explore in some modest detail the kinds of questions with which logic designers and practitioners concern themselves; 3) to develop an appreciation for the tremendous variation possible in digital design requirements and specifications, i. e,, for the complexity of the 'finite' digital problem, and hence an understanding of the need for systematic design techniques by which to attack such problems; 4) to gain some practice with the fundamental tools and techniques of logic design I so that the reader can adapt the techniques to the "new" problem presented by his own particular design constraints; and 5) to provide an introduction to the literature so that the discerning student can, in the future, dip into the ever growing literature in the field, and find it to some degree comprehensible, and advantageous to use

Retrieving information from compressed XML documents according to vague queries

XML has become the standard way for representing and transforming data over the World Wide Web. The problem with XML documents is that they have a very high ratio of redundancy, which makes these documents demanding large storage capacity and high network band-width for transmission. Because of their extensive use, XML documents could be retrieved according to vague queries by naive users with poor background in writing XPath query. The aim of this thesis is to present the design of a system named “XML Compressing and Vague Querying (XCVQ)” which has the ability of compressing the XML document and retrieving the required information from the compressed version with less decompression required according to vague queries. XCVQ first compressed the XML document by separating its data into containers and then compress these containers using the GZip compressor. The compressed file could be retrieved if a vague query is submitted without the need to decompress the whole file. For the purpose of processing the vague queries, XCVQ decomposes the query according to the relevant documents and then a second decomposition stage is made according to the relevant containers. Only the required information is decompressed and submitted to the user. To the best of our knowledge, XCVQ is the first XML compressor that has the ability to process vague queries. The average compression ratio of the designed compressor is around 78% which may be considered competitive compared to other queriable XML compressors. Based on several experiments, the query processor part had the ability to answer different kinds of vague queries ranging from simple exact match queries to complex ones that require retrieving information from several compressed XML documents.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fresh Techniques for Memory Profiling of Lazy Functional Programs

Lazy functional languages are known for their semantic elegance. They liberate programmers from many difficult responsibilities, such as the operational details of computations including memory management. However, the productivity and elegant semantics provided by lazy functional languages do not come without a cost. Lazy functional programs often suffer from unpredictable space leaks. For over two decades, various lazy functional implementations have been equipped with memory profiling tools. These tools furnish programmers with valuable information about space demands, but there is still scope for their future development. This dissertation presents two variants of memory profiling tools. The first tool is a hotspot heap profiler which presents information in two forms: profile charts and highlighted hotspots by source occurrence. The profile chart represents a hotspot-construction profile, distributed by hotspot temperatures. Hotspots are also marked in the textual display of source programs with the temperature they represent. Further information about hotspots is given in individual profiles. The second tool is a stack profiler which yields information about producers and construction of stack frames