In many monitoring applications, recent data is more important than distant data. How does this affect privacy of data analysis? We study a general class of data analyses --- predicate sums --- in this context.

Formally, we study the problem of ...

A common goal of privacy research is to release synthetic data that satisfies a formal privacy guarantee and can be used by an analyst in place of the original data. To achieve reasonable accuracy, a synthetic data set must be tuned to support a ...

While there is a large and growing body of literature on differentially private mechanisms for answering various classes of queries, to the best of our knowledge "count-range" queries have not been studied. These are a natural class of queries that ask "...

The task of formulating queries is greatly facilitated when they can be generated automatically from some given data values, schema concepts or both (e.g., names of particular entities and XML tags). This automation is the basis of various database ...

Formulating an XPath query over an XML document is a difficult chore for a non-expert user. This paper introduces a novel approach to ease the querying process. Instead of specifying a query, the user simply marks positive examples χ⁺ of nodes that fit ...

Group-by and top-k are fundamental constructs in database queries. However, the criteria used for grouping and ordering certain types of data -- such as unlabeled photos clustered by the same person ordered by age -- are difficult to evaluate by ...

We consider which queries are answerable in the presence of access restrictions and integrity constraints, and which portions of the schema are accessible in the presence of access restrictions and constraints. Unlike prior work, we focus on integrity ...

We study static analysis, in particular the containment problem, for analogs of conjunctive queries over XML documents. The problem has been studied for queries based on arbitrary patterns, not necessarily following the tree structure of documents. ...

Data exchange and schema mapping management have received little attention so far in the graph database scenario, and tools developed in this context for relational databases have significant drawbacks in the context of graph-structured data. In this ...

Most systems that have been developed for annotation of data assume a two-level structure in which annotation is superimposed on, and separate from, the data. However there are many cases in which an annotation may itself be annotated. For example ...

We study the problem of concealing functionality of a proprietary or private module when provenance information is shown over repeated executions of a workflow which contains both public and private modules. Our approach is to use provenance views to ...

We show that the evaluation of SPARQL algebra queries on various notions of annotated RDF graphs can be seen as particular cases of the evaluation of these queries on RDF graphs annotated with elements of so-called spm-semirings. Spm-semirings extend ...

Given a graph, a relation on its nodes, and a query language Q of interest, we study the Q-definability problem which amounts to deciding whether there exists a query in Q defining precisely the given relation over the given graph. Previous research has ...

XPath plays a prominent role as an XML navigational language due to several factors, including its ability to express queries of interest, its close connection to yardstick database query languages (e.g., first-order logic), and the low complexity of ...

Motivated by the current interest in languages for expressing path queries to graph databases, this paper proposes to investigate Walk Logic (WL): the extension of first-order logic on finite graphs with the possibility to explicitly quantify over ...

Active context-free games are two-player games on strings over finite alphabets with one player trying to rewrite the input string to match a target specification. These games have been investigated in the context of exchanging Active XML (AXML) data. ...

The analysis of datalog programs over relational structures has been studied in depth, most notably the problem of containment. The analysis problems that have been considered were shown to be undecidable with the exception of (i) containment of ...

In this paper we explore the problem of counting solutions to conjunctive queries. We consider a parameter called the quantified star size of a formula φ which measures how the free variables are spread in φ. We show that for conjunctive queries that ...

Unranked trees can be represented using their minimal dag (directed acyclic graph). For XML this achieves high compression ratios due to their repetitive mark up. Unranked trees are often represented through first child/next sibling (fcns) encoded ...

Integrity constraint management concerns both checking whether data is valid and taking action to restore correctness when invalid data is discovered. In XML the notion of valid data can be captured by schema languages such as Document Type Definitions (...