256,563 research outputs found

    On the evolution of conceptual modeling

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    Since the 1980s the need increased for overcoming idiosyncrasies of approaches to modeling in the various sub-disciplines of computing. The theoretical model of evolution is used in this paper for analyzing how computing and conceptual modeling have changed. It is concluded that computing has changed into a social phenomenon with a technical core and that therefore relying on (formal) model semantics as the sole tool for the discussion of conceptual modeling is no more adequate. A number of language games of computing is identified and the task set to describe these language games to the extent necessary for deciding whether or not they can serve as the foundation of computing

    An Approach to Conceptual Schema Evolution

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    In this work we will analyse conceptual foundations of user centric content management. Content management often involves integration of content that was created from different points of view. Current modeling techniques and especially current systems lack of a sufficient support of handling these situations. Although schema integration is undecideable in general, we will introduce a conceptual model together with a modeling and maintenance methodology that simplifies content integration in many practical situations. We will define a conceptual model based on the Higher-Order Entity Relationship Model that combines advantages of schema oriented modeling techniques like ER modeling with element driven paradims like approaches for semistructured data management. This model is ready to support contextual reasoning based on local model semantics. For the special case of schema evolution based on schema versioning we will derive the compatibility relation between local models by tracking dependencies of schema revisions. Additionally, we will discuss implementational facets, such as storage aspects for structurally flexible content or generation of adaptive user interfaces based on a conceptual interaction model

    Recommendation-Based Conceptual Modeling and Ontology Evolution Framework (CMOE+)

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    Within an enterprise, various stakeholders create different conceptual models, such as process, data, and requirements models. These models are fundamentally based on similar underlying enterprise (domain) concepts, but they differ in focus, use different modeling languages, take different viewpoints, utilize different terminology, and are used to develop different enterprise artifacts; as such, they typically lack consistency and interoperability. This issue can be solved by enterprise-specific ontologies, which serve as a reference during the conceptual model creation. Using such a shared semantic repository makes conceptual models interoperable and facilitates model integration. The challenge to accomplish this is twofold: on the one hand, an up-to-date enterprise-specific ontology needs to be created and maintained, and on the other hand, different modelers also need to be supported in their use of the enterprise-specific ontology. The authors propose to tackle these challenges by means of a recommendation-based conceptual modeling and an ontology evolution framework, and we focus in particular on ontology-based modeling support. To this end, the authors present a framework for Business Process Modeling Notation (BPMN) as a conceptual modeling language, and focus on how modelers can be assisted during the modeling process and how this impacts the semantic quality of the resulting models. Subsequently, a first, large-scale explorative experiment is presented involving 140 business students to evaluate the BPMN instantiation of our framework. The experiments show promising results with regard to incurred overheads, intention of use and model interoperability

    25 Years of Model-Driven Web Engineering : What we achieved, what is missing

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    Model-Driven Web Engineering (MDWE) approaches aim to improve the Web applications development process by focusing on modeling instead of coding, and deriving the running application by transformations from conceptual models to code. The emergence of the Interaction Flow Modeling Language (IFML) has been an important milestone in the evolution of Web modeling languages, indicating not only the maturity of the field but also a final convergence of languages. In this paper we explain the evolution of modeling and design approaches since the early years (the 90’s) detailing the forces which drove that evolution and discussing the strengths and weaknesses of some of those approaches. A brief presentation of IFML is accompanied with a thorough analysis of the most important achievements of the MDWE community as well as the problems and obstacles that hinder the dissemination of model-driven techniques in the Web engineering field.Laboratorio de Investigación y Formación en Informática Avanzada (LIFIA

    Inferring stabilizing mutations from protein phylogenies : application to influenza hemagglutinin

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    One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present a conceptual framework that explains how this requirement causes the probability that a particular amino acid mutation is fixed during evolution to depend on its effect on protein stability. We mathematically formalize this framework to develop a Bayesian approach for inferring the stability effects of individual mutations from homologous protein sequences of known phylogeny. This approach is able to predict published experimentally measured mutational stability effects (ΔΔG values) with an accuracy that exceeds both a state-of-the-art physicochemical modeling program and the sequence-based consensus approach. As a further test, we use our phylogenetic inference approach to predict stabilizing mutations to influenza hemagglutinin. We introduce these mutations into a temperature-sensitive influenza virus with a defect in its hemagglutinin gene and experimentally demonstrate that some of the mutations allow the virus to grow at higher temperatures. Our work therefore describes a powerful new approach for predicting stabilizing mutations that can be successfully applied even to large, complex proteins such as hemagglutinin. This approach also makes a mathematical link between phylogenetics and experimentally measurable protein properties, potentially paving the way for more accurate analyses of molecular evolution

    Spatial Dynamic Modeling and Urban Land Use Transformation:

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    Assessing the economic impacts of urban land use transformation has become complex and acrimonious. Although community planners are beginning to comprehend the economic trade-offs inherent in transforming the urban fringe, they find it increasingly difficult to analyze and assess the trade-offs expediently and in ways that can influence local decisionmaking. New and sophisticated spatial modeling techniques are now being applied to urban systems that can quickly assess the probable spatial outcomes of given communal policies. Applying an economic impact assessment to the probable spatial patterns can provide to planners the tools needed to quickly assess scenarios for policy formation that will ultimately help inform decision makers. This paper focuses on the theoretical underpinnings and practical application of an economic impact analysis submodel developed within the Land use Evolution and Impact Assessment Modeling (LEAM) environment. The conceptual framework of LEAM is described, followed by an application of the model to the assessment of the cost of urban sprawl in Kane County, Illinois. The results show the effectiveness of spatially explicit modeling from a theoretical and a practical point of view. The agent-based approach of spatial dynamic modeling with a high spatial resolution allows for discerning the macro-level implications of micro-level behaviors. These phenomena are highlighted in the economic submodel in the discussion of the implications of land use change decisions on individual and communal costs; low-density development patterns favoring individual behaviors at the expense of the broader community.

    Trends in conceptual modeling: Citation analysis of the ER conference papers (1979-2005)

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    Paper presented at The 11th International Conference of the International Society for Scientometrics and Informetrics (ISSI 2007). Madrid, Spain.We analyze thematic trends and challenging issues in conceptual modeling based on the metadata of 943 research papers published in a series of conferences on conceptual modeling (known as the ER conferences) between 1979 and 2005. We specifically address 1) all-time prominent challenges in conceptual modeling, 2) current challenges and emerging trends, and 3) the structure and dynamics of the conceptual modeling community. We utilize CiteSpace, a progressive domain visualization tool, to identify and visualize the movement of research fronts and intellectual bases, persistent clusters of papers, critical paths connecting these clusters, and the evolution of co-authorship networks as well as citation networks. The work contributes an indepth analysis of a major forum of conceptual modeling and a practical method that one can use as frequently as needed to keep abreast of the state of the art of conceptual modeling
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