document

Optimizing Database Joins: Cost Models and Benchmarking for CPU and GPU Systems

Matušovič, Marko (author)

Optimizing SQL query execution through effective cost models is a critical challenge in database management systems (DBMS). This thesis introduces a modular benchmarking system for cost models, with a pluggable architecture for both cost models and execution engines, enabling comprehensive benchmarking across various scenarios. Accompanied by a...

master thesis 2024

document

Acceleration of hybrid CPU-GPU query execution engine in Arrow Format

Su, Kexin (author)

General-purpose GPUs, renowned for their exceptional parallel processing capabilities and throughput, hold great promise for enhancing the efficiency of data analytics tasks. At the same time, recent developments in query execution engines have integrated the support of OLAP operations in a way that benefits from the zero serialization overhead...

master thesis 2023

document

Multimodal Input-Dependent Object Query Initialization for LiDAR-Camera 3D Object Detection with Transformers

van Geerenstein, Mathijs (author)

3D object detection models that exploit both LiDAR and camera sensor features are top performers in large-scale autonomous driving benchmarks. A transformer is a popular network architecture used for this task, in which so-called object queries act as candidate objects. Initializing these object queries based on current sensor inputs leads to...

master thesis 2023

document

Interactive semantic segmentation of 3D medical images: Comparative analysis of discrete and gradient descent based batch query retrieval methods in active learning

Vilakathara, Arjun (author)

Accurate segmentation of anatomical structures and abnormalities in medical images is crucial, but manual segmentation is time-consuming and automated approaches lack clinical accuracy. In recent years, active learning approaches that aim to combine automatic segmentation with manual input have gained attention in the field, aiming to reduce the...

bachelor thesis 2023

document

Testing Distributed Database Isolation through Anti-Pattern Detection

Qiu, Jingxuan (author)

Distributed databases often struggle to fulfill their transactional isolation guarantees due to sharding and replication. As a result, the problem of checking isolation levels is consistently receiving attention from academia and industries. Transactional dependency graphs form a useful abstraction to analyze the transactions’ dependencies and...

master thesis 2023

document

Optimizing machine learning inference queries for multiple objectives

Schönfeld, Mariette (author)

Machine learning inference queries are a type of database query for databases where a model pipeline is needed to evaluate its boolean predicates. Using a model zoo it is possible to select a variety of models to execute in a sequence rather than using a highly specialized model to answer every query predicate. Machine learning models can have...

master thesis 2022

document

Declarative Image Generation

Palakodeti, Anitej (author)

Generating synthetic images has wide applications in several fields such as creating datasets for machine learning or using these images to investigate the behaviour of machine learning models. An essential requirement when generating images is to control aspects such as the entities or objects in the image. Controlling this helps in creating...

master thesis 2022

document

Mapping User Intents in Web Search Queries to Types of Commonsense Knowledge

Huang, Xiaoao (author)

Commonsense knowledge is a type of knowledge consisting of facts that humans use every day. Humans make queries in search engines with different user intents, and some of them can be answered by knowledge tuples. Different types of knowledge are stored differently in the knowledge bases. Being aware of the types of commonsense knowledge required...

bachelor thesis 2022

document

S-Query: Opening the Black Box of Internal Stream Processor State

Verheijde, Jim (author)

At the moment we are witnessing the maturation of distributed streaming dataflow systems whose use-cases have departed from the mere analysis of streaming windows and complex-event processing, as they now extend to cloud applications, workflows and even e-commerce. The state of streaming operators has been so far hidden from external...

master thesis 2021

document

A Static-Based Approach to Detect SQL Semantic Bugs

Ion, Claudiu (author)

While SQL engines are now capable of detecting a large number of syntactic mistakes, most often semantic errors are not detected, which can lead to serious performance issues or even security vulnerabilities being introduced in the system. This thesis proposes a set of 25 validated heuristics together with a new rule-based static analysis tool...

master thesis 2021

document

Query Answerability Classifier for Direct Answer Module in Web Search Engines

Wang, Yiran (author)

In order determine when we can show direct answer module to user queries in web search engine, an independent classifier is designed in this study to assess the answerability of each user query. Real user queries are sampled from MS MARCO Question Answering and Natural Langauge Generation dataset \cite{MSMARCO} and manually labelled with query...

bachelor thesis 2021

document

A way to store, query, update an InSAR spatiotemporal dataset

Li, Ze (author)

In SAR interferometry, the data acquired by satellite are large. The points in the dataset are usually expressed in spatial-temporal dimension in which many epochs may be included. Extra information including contextual values and data from other sources sometimes are important to be taken into account when analyzing the deformation based on the...

student report 2020

document

Finding and materializing common subexpressions among queries in a query workload

Pasterkamp, Mark (author)

Most queries in a collection of queries, also called a query workload, to some degree have parts of their intermediate execution steps in common. These intermediate exe- cution steps, also called subexpressions, provide the opportunity to further optimize query workload execution in addition to the already existing query optimization done by the...

master thesis 2020

document

Word Embedding Models for Query Expansion in Answer Passage Retrieval

Roy, Nirmal (author)

With the increasing popularity of mobile and voice-assisted, extracting short and precise answer passages to open-domain questions is becoming an increasingly important information retrieval (IR) task. The recently released large-scale corpus for answer passage retrieval—WikiPassageQA—was shown to be challenging for both traditional retrieval...

master thesis 2019

document

Choosing from skyline sets

Touloumis, Konstantinos (author)

The skyline operator has been proposed to bridge the gap between traditional and multimedia database systems by finding the optimal objects according to the notion of Pareto dominance. According to the notion of Pareto dominance an object dominates another if it is better in one attribute and equal in all others. Skyline sets end up being pretty...

master thesis 2019

document

Shared Perspectives on Perceptual Features for Query by Example in E-Commerce Systems

Valle Torre, Manuel (author)

In this thesis, we focus on database query processing for so-called experience items, i.e., items commonly encountered in E-Commerce systems such as books, games or movies which are better described by their perceived subjective consumption experience, or Perceptual Features, than by factual meta-data normally used in SQL-style queries. To...

master thesis 2018

document

Implicit Parallelization of the Nested Relational Calculus for Semi-Structured Data

Hameete, P.A. (author)

Large volumes of data are produced, published and exchanged over the Internet. Such data is often in a semi-structured format which is typically irregular and therefore challenging to analyze. High-level data analysis languages are built on top of implicit parallel data processing platforms that handle distribution of computations and data....

master thesis 2016

document

A boolean QPQ using single photons

Nagtegaal, M.A. (author)

I propose an implementation of the quantum private query protocol as described in an article using a photon to encode a question and reflectionor transmission of the photon as answer options. Each question is represented by a photon in a transmission line with both ends returning to the user, and the answer is represented by reflection or...

bachelor thesis 2015

document

Suggesting Queries using Query-Flow Graphs to find Dutch Content with Curated Tags

Guijt, D.J. (author)

One of the standard features of today’s major Web search engines are query suggestions, which aid the user in the formulation of their search queries. Over the years, a number of different approaches have been proposed that have com- monly been evaluated in the standard Web search setting. In this thesis, we build a query suggestion pipeline...

master thesis 2014

document

Performance Evaluation of Distributed SQL Query Engines and Query Time Predictors

Van Wouw, S.F. (author)

With the decrease in cost of storage and computation of public clouds, even small and medium enterprises (SMEs) are able to process large amounts of data. This causes businesses to increase the amounts of data they collect, to sizes that are difficult for traditional database management systems to handle. Distributed SQL Query Engines (DSQEs),...

master thesis 2014