Specific Approaches -- Conceptual Modeling of Structure and Behavior with UML – The Top Level Object-Oriented Framework (TLOOF) Approach -- How to Manage Uniformly Software Architecture at Different Abstraction Levels -- Schema Integration Based on Uncertain Semantic Mappings -- Process Modeling and Views -- Combining Intention-Oriented and State-Based Process Modeling -- Pattern-Based Analysis of the Control-Flow Perspective of UML Activity Diagrams -- A Three-Layered XML View Model: A Practical Approach -- Conceptual Modeling in eLearning -- Modeling Group-Based Education -- Learning Process Models as Mediators Between Didactical Practice and Web Support -- Managing Models and Modeling -- A Fundamental View on the Process of Conceptual Modeling -- How to Tame a Very Large ER Diagram (Using Link Analysis and Force-Directed Drawing Algorithms) -- A Multilevel Dictionary for Model Management -- A MOF-Compliant Approach to Software Quality Modeling -- Requirements and Software Engineering -- Conceptual Modeling Based on Transformation Linguistic Patterns -- Applying Modular Method Engineering to Validate and Extend the RESCUE Requirements Process -- Security Patterns Meet Agent Oriented Software Engineering: A Complementary Solution for Developing Secure Information Systems -- Ontologies -- Kuaba Ontology: Design Rationale Representation and Reuse in Model-Based Designs -- Ontology Creation: Extraction of Domain Knowledge from Web Documents -- Choosing Appropriate Method Guidelines for Web-Ontology Building -- Web Services and Navigational Models -- Conceptual Model Based Semantic Web Services -- Automatically Grounding Semantically-Enriched Conceptual Models to Concrete Web Services -- Transforming Web Requirements into Navigational Models: AN MDA Based Approach -- Aspects of Workflow Modeling -- Accelerating Workflows with Fixed Date Constraints -- Workflow Data Patterns: Identification, Representation and Tool Support -- Actor-Oriented Design of Scientific Workflows -- Blueprints and Measures for ETL Workflows -- Queries and OLAP Summaries -- Vague Sets or Intuitionistic Fuzzy Sets for Handling Vague Data: Which One Is Better? -- A Semantic Approach to Query Rewriting for Integrated XML Data -- A Taxonomy of Inaccurate Summaries and Their Management in OLAP Systems -- Temporal and Spatial Modeling -- XCM: Conceptual Modeling for Dynamic Domains -- Precise Modeling and Verification of Topological Integrity Constraints in Spatial Databases: From an Expressive Power Study to Code Generation Principles -- Topological Relationships Between Complex Lines and Complex Regions.Conceptual modeling is fundamental to any domain where one must cope with complex real-world situations and systems because it fosters communication - tween technology experts and those who would bene?t from the application of those technologies. Conceptual modeling is the key mechanism for und- standing and representing the domains of information system and database - gineering but also increasingly for other domains including the new “virtual” e-environmentsandtheinformationsystemsthatsupportthem.Theimportance of conceptual modeling in software engineering is evidenced by recent interest in “model-drivenarchitecture”and“extremenon-programming”.Conceptualm- eling also plays a prominent rolein various technical disciplines and in the social sciences. The Annual International Conference on Conceptual Modeling (referred to as the ER Conference) provides a central forum for presenting and discussing current research and applications in which conceptual modeling is the major emphasis. In keeping with this tradition, ER 2005, the 24th ER Conference, spanned the spectrum of conceptual modeling including research and practice in areas such as theories of concepts and ontologies underlying conceptual m- eling, methods and tools for developing and communicating conceptual models, and techniques for transforming conceptual models into e?ective (information) system implementations. Moreover, new areas of conceptual modeling incl- ing Semantic Web services and the interdependencies of conceptual modeling with knowledge-based, logical and linguistic theories and approaches were also addressed.