Advances in Databases and Information Systems: 25th European Conference, ADBIS 2021, Tartu, Estonia, August 24–26, 2021, Proceedings

Preface
Organization
ADBIS’2021 Keynotes
Towards High-Quality Big Data: A Focus on Time
A Perspective on Prescriptive Learning
Data Exchange for Digital Government: Where Are We Heading?
Contents
Keynotes Talks
A Perspective on Prescriptive Learning ADBIS\'2021 Keynote
	1 Introduction
	2 Prescriptive Learning
	3 Reinforcement Learning
	4 Policy Gradient Optimization
	5 Join Ordering for Query Optimization
	6 Conclusion
	References
Data Exchange for Digital Government: Where Are We Heading? ADBIS’2021 Keynote
	1 The Data Exchange Platform X-Road
	2 A Digital Government Archtitecture Framework
	References
Patterns and Events
Maximal Mixed-Drove Co-Occurrence Patterns
	1 Introduction
	2 Related Work
	3 Definitions
	4 MAXMDCOP-Miner
	5 Experiments
	6 Summary and Future Work
	References
Efficiently Mining Large Gradual Patterns Using Chunked Storage Layout
	1 Introduction
	2 Preliminary Definitions
	3 State of the Art
	4 Proposed Chunking Approach
		4.1 Mapping Matrices into Chunked Layout
		4.2 GRAD-L Algorithm
		4.3 Computational Complexity
	5 Experiments
		5.1 Source Code
		5.2 Data Set Description
		5.3 Experiement Resultts
	6 Conclusion and Future Works
	References
A General Method for Event Detection on Social Media
	1 Introduction
	2 Related Work
	3 Generalized Representation of Temporal Social Media Text
	4 Generalized Multi-dimension Event Detection in Time Series
	5 Experimental Evaluation
		5.1 Evaluation Task
		5.2 Social Media Discussion Dataset
		5.3 Ground Truth Generation
		5.4 Recommending Newsworthy Words from Detected Events
		5.5 Baseline Methods
		5.6 Evaluation Results
	6 Conclusion
	References
5W1H Aware Framework for Representing and Detecting Real Events from Multimedia Digital Ecosystem
	1 Introduction
	2 Motivation
	3 Event Characteristics, Challenges, Opportunities and Approaches
	4 Related Work
	5 Preliminaries and Problem Definition
		5.1 Basic Definition
		5.2 Multimedia Object Dimensions Definition and Representation
	6 Proposed Framework
		6.1 Multimedia Object Extraction and Representation
		6.2 Cluster-Based Real Event Detection
	7 Similarity Measures and Cluster Comparison Strategies
		7.1 Similarity Measures
		7.2 Cluster Comparison Strategies
	8 Experimental Settings and Results
	9 Conclusion and Further Research
	References
Social Media and Text Mining
MONITOR: A Multimodal Fusion Framework to Assess Message Veracity in Social Networks
	1 Introduction
	2 Related Works
		2.1 Non-image Features
		2.2 Image Features
	3 MONITOR
		3.1 Multimodal Fusion Overview
		3.2 Feature Extraction and Selection
		3.3 Model Training
	4 Experiments
		4.1 Datasets
		4.2 Experimental Settings
		4.3 Classification Results
		4.4 Feature Analysis
	5 Conclusion and Perspectives
	References
Joint Management and Analysis of Textual Documents and Tabular Data Within the AUDAL Data Lake
	1 Introduction
	2 Metadata Management in AUDAL
		2.1 Intra-object Metadata
		2.2 Inter-object Metadata
		2.3 Global Metadata
	3 AUDAL\'s Architecture and Analysis Features
		3.1 AUDAL Architecture
		3.2 AUDAL\'s Analysis Features
	4 Quantitative Assessment of AUDAL
		4.1 Datasets and Query Workload
		4.2 Experimental Setup and Results
	5 Related Works
		5.1 Data Retrieval from Data Lakes
		5.2 Data Content Analysis from Data Lakes
		5.3 Discussion
	6 Conclusion and Future Works
	References
Aggregation and Summarization of Thematically Similar Twitter Microblog Messages
	1 Introduction
	2 Related Work
	3 Background and General Concept
	4 Data Preprocessing
	5 Data Clustering
	6 Data Aggregation
	7 Experiments
		7.1 Data Analysis and Runtime
		7.2 Aggregation and Summarization
	8 Summary and Conclusion
	References
Indexes, Queries and Constraints
Inserting Keys into the Robust Content-and-Structure (RCAS) Index
	1 Introduction
	2 Background
	3 Insertion of New Keys
	4 Index Restructuring During Insertion
		4.1 Strict Restructuring
		4.2 Lazy Restructuring
	5 Utilizing an Auxiliary Index
	6 Analysis
	7 Experimental Evaluation
		7.1 Runtime of Strict and Lazy Restructuring
		7.2 Query Runtime
		7.3 Merging of Auxiliary and Main Index
		7.4 Summary
	8 Related Work
	9 Conclusion and Outlook
	References
Optimizing Execution Plans in a Multistore
	1 Introduction
	2 Multistore Preliminaries
		2.1 Basic Concepts
		2.2 Dataspace Modeling
		2.3 Data Fusion Operations
	3 Query Plans and Optimization
	4 Cost Model
	5 Evaluation
	6 Related Work
	7 Conclusions
	References
Integrity Constraints for Microcontroller Programming in Datalog
	1 Introduction
	2 A Datalog-Variant for Microcontroller Systems
		2.1 Standard Datalog
		2.2 Datalog with States
		2.3 Interface Predicates
		2.4 Real Time
	3 Generalized Exclusion Constraints
	4 Refuting Violation Conditions
		4.1 Violation Conditions
		4.2 Proving Violation Conditions Inconsistent
	5 Conclusions
	References
Chance Constraint as a Basis for Probabilistic Query Model
	1 Introduction
	2 Problem Formulation
	3 Chance Constraint Model and Probabilistic Comparison Operators
	4 Conditioning as Application of Chance Constraints
	5 Examples
	6 Conclusion
	References
High-Dimensional Data and Data Streams
Unsupervised Feature Selection for Efficient Exploration of High Dimensional Data
	1 Introduction
	2 Background and Related Work
	3 Unsupervised Feature Selection with Clique Covers
	4 Evaluation
		4.1 Baseline Algorithms
		4.2 Performance Measure
	5 Conclusion
	References
MuLOT: Multi-level Optimization of the Canonical Polyadic Tensor Decomposition at Large-Scale
	1 Introduction
	2 Overview of Tensors and CP Decomposition
	3 State of the Art
	4 Distributed, Scalable and Optimized ALS for Apache Spark
		4.1 Distributed and Scalable Matrix Data Structures
		4.2 Mixing Three Principles of Optimization
		4.3 Stopping Criterion
		4.4 Data Centric Implementation
	5 Experiments
	6 Real Data Study
	7 Conclusion
	References
From Large Time Series to Patterns Movies: Application to Airbus Helicopters Flight Data
	1 Introduction
	2 From TS Data to Patterns Videos
	3 Implementation and Experimentations
	4 Evolution in Time of the Centroid of Co-occurrence Matrices
	5 Conclusion
	References
Data Integration
Experimental Evaluation Among Reblocking Techniques Applied to the Entity Resolution
	1 Introduction
	2 Preliminaries
		2.1 Entity Resolution
		2.2 Blocking
		2.3 ReBlocking
	3 Related Work
	4 Inside the Techniques
		4.1 Filtering Techniques
		4.2 Meta-Blocking Techniques
	5 Experimental Evaluation
		5.1 Datasets
		5.2 Evaluation Metrics
		5.3 Experimental Setup
		5.4 Performance of Techniques
	6 Conclusions
	References
FiLiPo: A Sample Driven Approach for Finding Linkage Points Between RDF Data and APIs
	1 Introduction
	2 Problem Statement
	3 Related Work
	4 Preliminaries
	5 Schema Matching and Mapping
		5.1 Probing Phase
		5.2 Aligning Phase: Candidate Alignment
		5.3 Aligning Phase: Final Alignment
	6 Evaluation
	7 Conclusion
	References
SMAT: An Attention-Based Deep Learning Solution to the Automation of Schema Matching
	1 Introduction
	2 Related Work
	3 SMAT: A DNN Model
		3.1 Problem Statement
		3.2 Overview
		3.3 Input Embedding and BiLSTM
		3.4 Attention-over-Attention (AOA)
		3.5 Data Augmentation and Controlled Batch Sample Ratio
	4 OMAP: A New Benchmark Dataset
	5 Experiments
		5.1 Dataset
		5.2 Baseline Models
		5.3 Experimental Setup
	6 Results
		6.1 Predictive Performance
		6.2 Training Size Sensitivity and Scalability
		6.3 Ablation Study
	7 Conclusion
	References
Towards a Cloud-WSDL Metamodel: A New Extension of WSDL for Cloud Service Description
	1 Introduction
	2 Background and Related Work
		2.1 WSDL
		2.2 Semantic Extensions
		2.3 Non-functional Properties Extensions
		2.4 Discussion
	3 Our Proposal: Cloud-WSDL Metamodel
		3.1 Overview of GCSD
		3.2 Adopted Methodology
	4 Comparison Between Cloud-WSDL and Other Description Languages
	5 Conclusion
	References
Author Index