439,971 research outputs found

    Model Transformation Technologies in the Context of Modelling Software Systems

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    Programming technologies have improved continuously during the last decades, but from an Information Systems perspective, some well-known problems associated to the design and implementation of an Information Systems persists. Object-Oriented Methods, Formal Specification Languages, Component-Based Software Production... This is just a very short list of technologies proposed to solve a very old and, at the same time, very well-known problem: how to produce software of quality. Programming has been the key task during the last 40 years, and the results have not been successful yet. This work will explore the need of facing a sound software production process from a different perspective: the non-programming perspective, where by non-programming we mainly mean modeling. Instead of talking about Extreme Programming, we will introduce a Extreme Non-Programming (Extreme Modeling-Oriented) approach. We will base our ideas on the intensive work done during the last years, oriented to the objective of generating code from a higher-level system specification, normally represented as a Conceptual Schema. Nowadays, though, the hip around MDA has given a new push to these strategies. New methods propose sound model transformations which cover all the different steps of a sound software production process from an Information Systems Engineering point of view. This must include Organizational Modeling, Requirements Engineering, Conceptual Modeling and Model-Based Code Generation techniques. In this context, it seems that the time of Model Transformation Technologies is finally here..

    The logic of adaptive behavior : knowledge representation and algorithms for the Markov decision process framework in first-order domains

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    Learning and reasoning in large, structured, probabilistic worlds is at the heart of artificial intelligence. Markov decision processes have become the de facto standard in modeling and solving sequential decision making problems under uncertainty. Many efficient reinforcement learning and dynamic programming techniques exist that can solve such problems.\ud Until recently, the representational state-of-the-art in this field was based on propositional representations.\ud \ud However, it is hard to imagine a truly general, intelligent system that does not conceive of the world in terms of objects and their properties and relations to other objects. To this end, this book studies lifting Markov decision processes, reinforcement learning and dynamic programming to the first-order (or, relational) setting. Based on an extensive analysis of propositional representations and techniques, a methodological translation is constructed from the propositional to the relational setting. Furthermore, this book provides a thorough and complete description of the state-of-the-art, it surveys vital, related historical developments and it contains extensive descriptions of several new model-free and model-based solution techniques

    Nitrogen as a Capital Input and Stock Pollutant: A Dynamic Analysis of Corn Production and Nitrogen Leaching under Non-Uniform Irrigation

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    A spatially dynamic programming model of nonuniform irrigation is developed to investigate the nitrogen leaching problem associated with irrigated agriculture. We evaluate the importance of temporal and spatial elements in (i) appropriately modeling the interseasonal corn production problem with nitrogen carry-over and leaching under non-uniform irrigation, and (ii) in adequately evaluating alternative policy instruments for pollution control. Comparisons of the time profiles under spatially variable nitrogen levels arising from nonuniform irrigation are provided along with an evaluation of three different price-based policy instruments for reducing nitrogen leaching.Environmental Economics and Policy,

    Evaluation of topic-based adaptation and student modeling in QuizGuide

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    This paper presents an in-depth analysis of a nonconventional topic-based personalization approach for adaptive educational systems (AES) that we have explored for a number of years in the context of university programming courses. With this approach both student modeling and adaptation are based on coarse-grained knowledge units that we called topics. Our motivation for the topic-based personalization was to enhance AES transparency for both teachers and students by utilizing typical topic-based course structures as the foundation for designing all aspects of an AES from the domain model to the end-user interface. We illustrate the details of the topic-based personalization technology, with the help of the Web-based educational service QuizGuide—the first system to implement it. QuizGuide applies the topic-based personalization to guide students to the right learning material in the context of an undergraduate C programming course. While having a number of architectural and practical advantages, the suggested coarse-grained personalization approach deviates from the common practices toward knowledge modeling in AES. Therefore, we believe that several aspects of QuizGuide required a detailed evaluation—from modeling accuracy to the effectiveness of adaptation. The paper discusses how this new student modeling approach can be evaluated, and presents our attempts to evaluate it from multiple different prospects. The evaluation of QuizGuide across several consecutive semesters demonstrates that, although topics do not always support precise user modeling, they can provide a basis for successful personalization in AESs
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