98,238 research outputs found

    Graphical models for marked point processes based on local independence

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    A new class of graphical models capturing the dependence structure of events that occur in time is proposed. The graphs represent so-called local independences, meaning that the intensities of certain types of events are independent of some (but not necessarily all) events in the past. This dynamic concept of independence is asymmetric, similar to Granger non-causality, so that the corresponding local independence graphs differ considerably from classical graphical models. Hence a new notion of graph separation, called delta-separation, is introduced and implications for the underlying model as well as for likelihood inference are explored. Benefits regarding facilitation of reasoning about and understanding of dynamic dependencies as well as computational simplifications are discussed.Comment: To appear in the Journal of the Royal Statistical Society Series

    Learning Outcomes For Economists

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    Articulating thoughtful learning outcome statements for courses and majors improves teaching and learning and satisfies accreditation requirements. After reading this paper, economists will be able to construct learning outcome statements that guide and enhance teaching and learning in their courses and programs. We present a framework for developing learning outcomes based on a set of five fundamental competencies in economics. We then provide another public good, offering a complete set of learning outcomes for an introductory microeconomics course, which instructors can include in their syllabi. For additional guidance, we construct examples of lesson-specific learning outcomes as well

    Reasoning about Independence in Probabilistic Models of Relational Data

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    We extend the theory of d-separation to cases in which data instances are not independent and identically distributed. We show that applying the rules of d-separation directly to the structure of probabilistic models of relational data inaccurately infers conditional independence. We introduce relational d-separation, a theory for deriving conditional independence facts from relational models. We provide a new representation, the abstract ground graph, that enables a sound, complete, and computationally efficient method for answering d-separation queries about relational models, and we present empirical results that demonstrate effectiveness.Comment: 61 pages, substantial revisions to formalisms, theory, and related wor

    Secondary mathematics guidance papers: summer 2008

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    Requirements modelling and formal analysis using graph operations

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    The increasing complexity of enterprise systems requires a more advanced analysis of the representation of services expected than is currently possible. Consequently, the specification stage, which could be facilitated by formal verification, becomes very important to the system life-cycle. This paper presents a formal modelling approach, which may be used in order to better represent the reality of the system and to verify the awaited or existing system’s properties, taking into account the environmental characteristics. For that, we firstly propose a formalization process based upon properties specification, and secondly we use Conceptual Graphs operations to develop reasoning mechanisms of verifying requirements statements. The graphic visualization of these reasoning enables us to correctly capture the system specifications by making it easier to determine if desired properties hold. It is applied to the field of Enterprise modelling
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