Conceptual Graphs Are Also Graphs.- Argumentation-Based Paraconsistent Logics.- Towards a Framework for Learning from Networked Data.- Games on Graphs.- A Partial-Closure Canonicity Test to Increase the Efficiency of CbO-Type Algorithms.- On Conceptual Graphs and Explanation of Query Answering under Inconsistency.- Defining Key Semantics for the RDF Datasets: Experiments and Evaluations.- A Framework for Qualitative Representation and Reasoning about Spatiotemporal Patterns.- Combining Restricted Boltzmann Machine and One Side Perceptron for Malware Detection.- Knowledge Management and Human Trafficking: Using Conceptual Knowledge Representation, Text Analytics and Open-Source Data to Combat Organized Crime.- Default Reasoning Implementation in CoGui.- Extracting Threshold Conceptual Structures from Web Documents.- A Formal Topology of Web Classification.- Specifying Well-Formed Part-Whole Relations in Coq.- Automatic Extraction of Semantic Relations by Using Web Statistical Information.- Efficient Representation of Extensional Constraints.- On the Usability of Random Indexing in Patent Retrieval.- Teaching Syllogistics Using Conceptual Graphs.- Principles of Regulated Activation Networks.- Computing Concept Lattices from Very Sparse Large-Scale Formal Contexts.- Swip: A Natural Language to SPARQL Interface Implemented with SPARQL.- Environmental Scanning and Knowledge Representation for the Detection of Organised Crime Threats.- Combining Business Intelligence with Semantic Technologies: The CUBIST Project.- FCA-Based Recommender Models and Data Analysis for Crowdsourcing Platform Witology.- Conceptual Structures in Leading and Best Enterprise Practices.- Eco-Efficient Packaging Material Selection for Fresh Produce: Industrial Session.

This book constitutes the proceedings of the 21st International Conference on Conceptual Structures, ICCS 2014, held in Iasi, Romania, in July 2014. The 17 regular papers and 6 short papers presented in this volume were carefully reviewed and selected from 40 and 10 submissions, respectively. The topics covered are: conceptual structures, knowledge representation, reasoning, conceptual graphs, formal concept analysis, semantic Web, information integration, machine learning, data mining and information retrieval.