1,721,086 research outputs found
Extending Spider Diagrams for policy definition
No full textSpider Diagrams (SDs) are a well-established visual language used to specify sets, their relationships, and constraints on their cardinalities. We propose two extensions allowing their use in the definition of temporal policies. Firstly, Timed SDs (TSDs) enable the expression of temporal constraints. We adopt an interval-based model of calendar time, permitting diagram elements to be specified to exist only over some interval. We introduce basic TSDs, where time constraints refer to an entire diagram rather than individual elements, as a canonical form for TSDs, and decompose complex TSDs into comic strip-like sequences of basic TSDs. Secondly, we introduce an innovative usage of SDs by specialising and adapting them to an OO-modelling context: in type-SDs a spider represents a type, whereas in instance-SDs a spider represents a specific object of a given type. A notion of conformance of an instance-SD to a type-SD ensues and we extend the concepts to instance-TSDs and type-TSDs. Finally, we combine extensions to allow the specification of temporal policies, which define permissible states for instances of some given type over a period without temporal gaps in it, and introduce a notion of conformance to a policy for a sequence of time-annotated instances. (C) 2012 Elsevier Ltd. All rights reserved
Online region computations for Euler diagrams with relaxed drawing conventions
Full text linkAbstractEuler diagrams are an accessible and effective visualisation of data involving simple set-theoretic relationships. Efficient algorithms to quickly compute the abstract regions of an Euler diagram upon curve addition and removal have previously been developed (the single marked point approach, SMPA), but a strict set of drawing conventions (called well-formedness conditions) were enforced, meaning that some abstract diagrams are not representable as concrete diagrams. We present a new methodology (the multiple marked point approach, MMPA) enabling online region computation for Euler diagrams under the relaxation of the drawing convention that zones must be connected regions. Furthermore, we indicate how to extend the methods to deal with the relaxation of any of the drawing conventions, with the use of concurrent line segments case being of particular importance. We provide complexity analysis and compare the MMPA with the SMPA. We show that these methods are theoretically no worse than other comparators, whilst our methods apply to any case, and are likely to be faster in practise due to their online nature. The machinery developed for the concurrency case could be of use in Euler diagram drawing techniques (in the context of the Euler Graph), and in computer graphics (e.g. the development of an advanced variation of a winged edge data structure that deals with concurrency). The algorithms are presented for generic curves; specialisations such as utilising fixed geometric shapes for curves may occur in applications which can enhance capabilities for fast computations of the algorithms' input structures. We provide an implementation of these algorithms, utilising ellipses, and provide time-based experimental data for benchmarking purposes
Policy Specifications with Timed Spider Diagrams
No full textSpider Diagrams are a well-established visual language used to specify sets, their relationships, and constraints on their cardinalities but they have no means of specifying temporal aspects of a system. Timed Spider Diagrams are an evolution enabling the specification of temporal constraints, with a granular-based time system, for use in areas such as policy specification. In this paper we introduce event based actions to this framework and illustrate with examples from models of an automatic parking meter system, and an internet billing system
Visual Exploration System in an Industrial Context
Full text linkThis paper describes ExploraTool, a new interactive tool to visually explore data from multiple repositories. The tool has been applied in a real setting to explore computational fluid dinamics (CFD) simulation data and obtain new insights into the space of simulations. The inclusion of free exploration, filtering operations, and chart generation provides a quick method for performance comparisons. The paper proposes an algorithmic means of processing input in the form of tabular data sets, generating a plausible hierarchical structure over metadata categories, which is used to initialize the visualization together with interactions' methods to explore, select, and compare sets of simulation data. This paper also reports on the evaluation study performed involving 24 engineers over two distinct locations from a large automotive manufacturer to evaluate the usability and the overall user satisfaction with the tool. Participants rated the tool as intuitive, useful, and effective
Annotating spiders with resource information
No full textThe recently introduced notion of Modeling Spider Diagrams immerses Spider Diagrams in a modelling context. We enhance here their capabilities by including references to resources that are required to persist in some state or to perform some state transition. To this end, we introduce a notion of annotation, which can be expressed through a restriction of Conceptual Spider Diagrams (extended over domains), where domains are partially ordered and predicate edges have to be consistent with this ordering. The resulting notion of Annotated Modeling Spider Diagrams can then be used to express constraints on the usage of resources, so that conformance to a policy can be verified with respect to resource availability. We provide additional options for user-modelling choices via a natural equivalent representation in terms of (classical) Spider Diagrams, restricted on the domain of interest, and the use of colour for domain identification
Simulation repository visualisation and exploration
Full text linkThis paper describes a tool called ExploraTool to visualise, explore and graphically query large repositories of simulations. Instead of starting with the empty list, ExploraTool provides an initial overview of the repository content, progressively grouping the simulations by their main attributes, such as brand, vehicle model, power source, engine type and so on. Users can interactively navigate the repository view through drill-down, roll-up and rearrangement operations. In this way, using the ExploraTool, simulation analysts can visualise, explore and filter large repository of simulations as well as select groups of simulations to compare their performances
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Visual and textual dataset exploration
No full textExploraTool is a tool to visually and textually explore, filter and select data within simulation repositories. The tool groups items together by their main attribute values. Groups are represented as nested ellipses. Drill-down and rollup operations are provided. In this paper, we extend by adding a textual based search facility that updates the visualisation, allowing at same time textual and visual queries. ExploraTool's features, challenges to face and future work have been discussed
Resource-aware policies
Full text linkIn previous papers, we proposed an extension of Spider Diagrams to object-oriented modelling, called Modelling Spider Diagrams (MSDs), as a visual notation for specifying admissible states of instances of types, and for verifying the conformance of configurations of instances with such specifications. Based on this formalisation, we developed a notion of transformation of MSDs, modelling admissible evolutions of configurations. In the original version of MSD, individual instances evolve independently, but in reality evolutions often occur in the context of available resources, so transformations must be extended to take this into account. In this paper we provide an abstract syntax for MSDs, in terms of typed attributed graphs, and a semantics for the specification of policies based on notions from the theory of graph transformations, and we associate with them a notion of resources. We also introduce a synchronisation mechanism, based on annotation of instances with resources, so that the transformations required by a policy occur with respect to available resources. In particular, resources can be atomically produced or consumed or can change their state consistently with the evolution of the spiders subject to the policy
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