Evangelia A. Sitaridi

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Scheduling data processing workflows (dataflows) on the cloud is a very complex and challenging task. It is essentially an optimization problem, very similar to query optimization, that is characteristically different from traditional problems in two aspects: Its space of alternative schedules is very rich, due to various optimization opportunities that(More)
Modern frameworks, such as Hadoop, combined with abundance of computing resources from the cloud, offer a significant opportunity to address long standing challenges in distributed processing. Infrastructure-as-a-Service clouds reduce the investment cost of renting a large data center while distributed processing frameworks are capable of efficiently(More)
Implementations of database operators on GPU processors have shown dramatic performance improvement compared to multicore-CPU implementations. GPU threads can cooperate using shared memory, which is organized in interleaved banks and is fast only when threads read and modify addresses belonging to distinct memory banks. Therefore, data processing operators(More)
Implementations of relational operators on GPU processors have resulted in order of magnitude speedups compared to their multicore CPU counterparts. Here we focus on the efficient implementation of string matching operators common in SQL queries. Due to different architectural features the optimal algorithm for CPUs might be suboptimal for GPUs. GPUs(More)
Complex on-demand data retrieval and processing is a characteristic of several applications and combines the notions of querying & search, information filtering & retrieval, data transformation & analysis, and other data manipulations. Such rich tasks are typically represented by data processing graphs, having arbitrary data operators as nodes and their(More)
AITION is a scalable, user-friendly, and interactive data mining (DM) platform, designed for analyzing large heterogeneous datasets. Implementing state-of-the-art machine learning algorithms, it successfully utilizes generative Probabilistic Graphical Models (PGMs) providing an integrated framework targeting feature selection, Knowledge Discovery (KD), and(More)
String processing tasks are common in analytical queries powering business intelligence. Besides substring matching, provided in SQL by the like operator, popular DBMSs also support regular expressions as selective filters. Substring matching can be optimized by using specialized SIMD instructions on mainstream CPUs, reaching the performance of numeric(More)