Direct manipulation interface

Résumé

In computer science, human–computer interaction, and interaction design, direct manipulation is an approach to interfaces which involves continuous representation of objects of interest together with rapid, reversible, and incremental actions and feedback. As opposed to other interaction styles, for example, the command language, the intention of direct manipulation is to allow a user to manipulate objects presented to them, using actions that correspond at least loosely to manipulation of physical objects. An example of direct manipulation is resizing a graphical shape, such as a rectangle, by dragging its corners or edges with a mouse. Having real-world metaphors for objects and actions can make it easier for a user to learn and use an interface (some might say that the interface is more natural or intuitive), and rapid, incremental feedback allows a user to make fewer errors and complete tasks in less time, because they can see the results of an action before completing the acti

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https://en.wikipedia.org/wiki/Direct_manipulation_interface

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Chargement

Reduced Basis method for Isogeometric Analysis: application to structural problems

Marina Rinaldi

Isogeometric Analysis (IGA) is a computational methodology for the numerical approximation of Partial Differential Equations (PDEs). IGA is based on the isogeometric concept, for which the same basis functions, usually Non-Uniform Rational B-Splines (NURBS), are used both to represent the geometry and to approximate the unknown solutions of PDEs. Compared to the standard Finite Element method, NURBS-based IGA offers several advantages: ideally a direct interface with CAD tools, exact geometrical representation, simple refinement procedures, and smooth basis functions allowing to easily solve higher order problems, including structural shell problems. In these contexts, repeatedly solving a problem for a large set of geometric parameters might lead to high and eventually prohibitive computational cost. To cope with this problem, we consider in this work the Reduced Basis (RB) method for the solution of parameter dependent PDEs, specifically for which the NURBS representation of the computational domain is parameter dependent. RB refers to a technique that enables a rapid and reliable approximation of parametrized PDEs by constructing low dimensional approximation spaces. In this work, for the construction of the reduced spaces we adopt two different strategies, namely the Proper Orthogonal Decomposition and the greedy algorithm. In this thesis we combine RB and IGA for the efficient solution of parametrized problems for all the possible cases of NURBS geometrical parametrizations, which specifically include the NURBS control points, the weights, and both the control points and weights. In particular, we first focus on the solution of second order PDEs on parametrized lower dimensional manifolds, specifically surfaces in the three dimensional space. We consider geometrical parametrizations that entail a nonaffine dependence of the variational forms on the spatial coordinates and the geometric parameters. Thus, depending on the parametrization at hand and in order to ensure a suitable Offline/Online decomposition between the reduced order model construction and solution, we resort to the Empirical Interpolation Method (EIM) or the Matrix Discrete Empirical Interpolation Method (MDEIM), by comparing their performances. As application, we solve a class of benchmark structural problems modeled by Kirchoff-Love shells for which we consider NURBS geometric parametrizations and we apply the RB method to the solution of this class of fourth order PDEs. We highlight by means of numerical tests, the performance of the RB method applied to standard IGA approximation of parametrized shell geometries.

2015

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How Users Perceive and Appraise Personalized Recommendations

Li Chen, Nicolas Jones, Pearl Pu Faltings

Traditional websites have long relied on users revealing their preferences explicitly through direct manipulation interfaces. However recent recommender systems have gone as far as using implicit feedback indicators to understand users' interests. More than a decade after the emergence of recommender systems, the question whether users prefer them compared to stating their preferences explicitly, largely remains a subject of study. Even though some studies were found on users' acceptance and perceptions of this technology, these were general marketing-oriented surveys. In this paper we report an in-depth user study comparing Amazon's implicit book recommender with a baseline model of explicit search and browse. We address not only the question “do people accept recommender systems” but also how or under what circumstances they do and more importantly, what can still be improved.

Springer2009

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SUPER is an exploratory project into the next generation of user-DBMS interfaces. Its main objective is to demonstrate that a visual paradigm can lead to powerful and user-friendly interfaces supporting all phases of the database life cycle (i.e. creation, manipulation and evolution). Visual interaction in SUPER is based on direct manipulation of objects and functions, with a special focus on providing users with maximum flexibility and independence from database technicalities. The set of tools offers facilities to meet the varied demands from categories of users with different levels of skill. Diagrammatic representations and a basic set of functions are better suited for novice and occasional users, while menus and dialog boxes speed up the dialog for expert users. At the same times a consistent interaction style over the various functions and tools has been emphasized. SUPER has been designed as a front end to a relational or an object-oriented DBMS, i.e. the persistence of data, consistency and concurrency problems are delegated to an off-the-shelf database management system. The current prototype supports schema definition, query formulation and browsing using a powerful data model based on objects and relationships.

1995

Chargement

Reduced Basis method for Isogeometric Analysis: application to structural problems

Marina Rinaldi

2015