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Generating databases for testing database applications (e.g., OLAP or business objects) is a daunting task in practice. There are a number of commercial tools to automatically generate test databases. These tools take a database schema (table layouts plus integrity constraints) and table sizes as input in order to generate new tuples. However, the databases(More)
Today, a common methodology for testing a database management system (DBMS) is to generate a set of test databases and then execute queries on top of them. However, for DBMS testing, it would be a big advantage if we can control the input and/or the output (e.g., the cardinality) of each individual operator of a test query for a particular test case.(More)
In many applications, information is best represented as graphs. In a dynamic world, information changes and so the graphs representing the information evolve with time. We propose that historical graph-structured data be maintained for analytical processing. We call a historical evolving graph sequence an EGS. We observe that in many applications, graphs(More)
After decades of effort working on database performance, the quality and the usability of database systems have received more attention in recent years. In particular, the feature of explaining missing tuples in a query result, or the so-called "why-not" questions, has recently become an active topic. In this paper, we study the problem of answering why-not(More)
To evaluate the performance of database applications and DBMSs, we usually execute workloads of queries on generated databases of different sizes and measure the response time. This paper introduces MyBenchmark, an offline data generation tool that takes a set of queries as input and generates database instances for which the users can control the(More)
Hepcidin is a peptide hormone that regulates iron homeostasis and acts as an antimicrobial peptide. It is expressed and secreted by a variety of cell types in response to iron loading and inflammation. Hepcidin mediates iron homeostasis by binding to the iron exporter ferroportin, inducing its internalization and degradation via activation of the protein(More)
Regression testing is an important software maintenance activity to ensure the integrity of a software after modification. However, most methods and tools developed for software testing today do not work well for database applications; these tools only work well if applications are stateless or tests can be designed in such a way that they do not alter the(More)
Skyline queries return a set of interesting data points that are not dominated on all dimensions by any other point. Most of the existing algorithms focus on skyline computation in centralized databases, and some of them can progressively return skyline points upon identification rather than all in a batch. Processing skyline queries over the Web is a more(More)
Caching is an important optimization in search engine architectures. Existing caching techniques for search engine optimization are mostly biased towards the reduction of random accesses to disks, because random accesses are known to be much more expensive than sequential accesses in traditional magnetic hard disk drive (HDD). Recently, solid state drive(More)
Hepcidin is a hormone secreted in response to iron loading and inflammation. Hepcidin binds to the iron exporter ferroportin, inducing its degradation and thus preventing iron entry into plasma. We determined that hepcidin binding to ferroportin leads to the binding and activation of the protein Janus Kinase2 (Jak2), which is required for phosphorylation of(More)