| 1. |
- Engelson, Vadim, 1965-, et al.
(author)
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Automatic generation of user interfaces from data structure specifications and object-oriented application models
- 1996
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In: ECOOP ’96 — Object-Oriented Programming. - : Springer Berlin/Heidelberg. - 9783540614395 ; , s. 114-141
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Conference paper (peer-reviewed)abstract
- Applications in scientific computing operate with data of complex structure and graphical tools for data editing, browsing and visualization are necessary.Most approaches to generating user interfaces provide some interactive layout facility together with a specialized language for describing user interaction. Realistic automated generation approaches are largely lacking, especially for applications in the area of scientific computing.This paper presents two approaches to automatically generating user interfaces (that include forms, pull-down menus and pop-up windows) from specifications.The first is a semi-automatic approach, that uses information from object-oriented mathematical models, together with a set of predefined elementary types and manually supplied layout and grouping information. This system is currently in industrial use. A disadvantage is that some manual changes need to be made after each update of the model.Within the second approach we have designed a tool, PDGen (Persistence and Display Generator) that automatically creates a graphical user interface and persistence routines from the declarations of data structures used in the application (e.g., C++ class declarations). This largely eliminates the manual update problem. The attributes of the generated graphical user interface can be altered.Now structuring and grouping information is automatically extracted from the object-oriented mathematical model and transferred to PDGen. This is one of very few existing practical systems for automatically generating user interfaces from type declarations and related object-oriented structure information.
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| 2. |
- Engelson, Vadim, et al.
(author)
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Generating efficient 3D graphics animation code with OpenGL from object oriented models in Mathematica
- 1997
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In: Innovation in Mathematics. ; , s. 129-136
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Conference paper (peer-reviewed)abstract
- Traditionally 3D plots of parametric functions expressed in Mathematica are computed interpretively and saved in a static form before display. This causes low graphic performance. In this paper we describe an approach to generate efficient C++/Fortran90 code from such functions. This code is linked together with a powerful 3D browsing environment and uses OpenGL with possible hardware support. Thus flexibility of interactive exploration of 3D scenes and animation options become available for the end-user. 1 Introduction 1.1 The visualization problem Numerical experiments based on mathematical models is one of the most prevalent classes of applications of high performance computers and workstations. A common problem is however to interpret and make use of numerical data produced from such experiments. High performance numerical programs usually generate vast amounts of data (in our applications 1-2 Gbyte or more).
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| 3. |
- Engelson, Vadim, 1965-, et al.
(author)
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Lossless compression of high-volume numerical data from simulations
- 2000
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In: Proceedings. DCC 2000 Data Compression Conference, 2000. - : IEEE. - 0769505929
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Conference paper (peer-reviewed)abstract
- Summary form only given. We propose a lossless algorithm of delta compression (a variant of predictive coding) that attempts to predict the next point from previous points using higher-order polynomial extrapolation. In contrast to traditional predictive coding our method takes into account varying (non-equidistant) domain (typically, time) steps. To save space and guarantee lossless compression, the actual and predicted values are converted to 64-bit integers. The residual (difference between actual and predicted values) is computed as difference of integers. The unnecessary bits of the residual are truncated, e.g., 1111110101 is replaced by 10101. The length of the bit sequence (510=(000101)2) is prepended
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| 4. |
- Engelson, Vadim, 1965-, et al.
(author)
-
Lossless Compression of High-volume Numerical Data from Simulations
- 2000
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Reports (other academic/artistic)abstract
- Applications in scientific computing operate with high-volume numerical data and the occupied space should be reduced. Traditional compression algorithms cannot provide sufficient compression ratio for such kinds of data. We propose a lossless algorithm of delta-compression (a variant of predictive coding) that packs the higher-order differences between adjacent data elements. The algorithm takes into account varying domain (typically, time) steps. The algorithm is simple, it has high performance and delivers a high compression ratio for smoothly changing data. Both lossless and lossy variants of the algorithm can be used. The algorithm has been successfully applied to the output from a simulation application that uses a solver of ordinary differential equations.
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| 5. |
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| 6. |
- Engelson, Vadim, 1965-, et al.
(author)
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Using the Mathematica environment for generating efficient 3D graphics
- 1997
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In: Proceedings of EDUGRAPHICS/COMPUGRAPHICS-97. - : Graphic Science Promotions and Publications. ; , s. 222-231
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Conference paper (peer-reviewed)abstract
- Mathematica is an integrated environment for symbolic transformation of mathematical formulas. This environment has applications in scientific computing, scientific visualization and education. Mathematica gives possibility to describe visualized objects in form of mathematical formulas and expressions. Such descriptions are more clear and concise than low-level C or C++ code. Many visualization systems require input in the form of (sometimes huge) data files, which is a disadvantage for highly interactive and animated 3D graphics applications. This is also the case for graphics expressed in Mathematica which is computed interpretively and saved in a static data form before display. This causes low graphic performance. In this paper we describe an approach which uses object geometry descriptions in the form of efficient program code instead of huge data files. We have built a tool that produces 3D visualizations of geometrical objects and object trajectories from mathematical specifications expressed as parametric functions in Mathematica. A compiler has been developed which generates efficient C++ code from such functions and symbolic expressions. This code is linked together with a powerful 3D browsing environment and uses OpenGL with possible hardware support. All the computations are performed within the visualizing application. Object geometry, color, etc. can be changed dynamically during animations. Thus the flexibility of interactive exploration of 3D scenes and animation become available for the end-user.
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| 7. |
- Fritzson, Dag, et al.
(author)
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Object-Oriented Mathematical Modelling – Applied to Machine Elements
- 1994
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In: Computers & structures. - : Elsevier. - 0045-7949 .- 1879-2243. ; 51:3, s. 241-253
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Journal article (peer-reviewed)abstract
- Machine element analysis has a goal of describing function and other aspects of machine elements in a theoretical form. This paper shows how ideas from object-oriented modelling can be applied to machine element analysis. The models thus obtained are both easier to understand, better structured, and allow a higher degree of re-use than conventional models. An object-oriented model description is natural and suitable for machine element analysis. As a realistic example an equational model of rolling bearings is presented. The structure of the model is general, and applies to many types of rolling bearings. The model and one solution require approximately 200 + 200 equations. The model is extensible, e.g. simple submodels of detailed properties can be made more complex without altering the overall structure. The example model has been implemented in a language of our own design, ObjectMath (Object-oriented Mathematical language for scientific computing). Using ObjectMath, it is possible to model classes of equation objects, to support multiple and single inheritance of equations, to support composition of equations, and to solve systems of equations. Algebraic transformations can conveniently be done since ObjectMath models are translated into the Mathematica computer algebra language. When necessary, equations can be transformed to C++ code for efficient numerical solution. The re-use of equations through inheritance reduced the size of the model by a factor of two, compared to a direct representation of the model in the Mathematica computer algebra language.
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| 8. |
- Fritzson, Dag, et al.
(author)
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Object-Oriented Mathematical Modelling - Applied to Rolling Bearings
- 1992
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Conference paper (peer-reviewed)abstract
- Machine element analysis has the goal of describing functionality and other important aspects of machine elements in theoretical form. A rolling bearing is a typical example of a machine element. The first issue covered in this paper is how ideas from object-oriented programming and modelling can be applied to machine element analysis. The models thus obtained are easier to understand, better structured, and allow a higher degree of re-use than conventional models. Our conclusion is that an object-oriented model description is natural for the machine element analyst and is suitable for machine element analysis.An equational model of rolling bearings is presented in this paper. The structure of the model is general, in three dimensions, and applies to many types of rolling bearings. Part of this generality is obtained by using parametric surfaces. In order to keep the presentation of the model understandable, we have simplified many details. Nevertheless, the model and one solution require approximately 200+200 equations. The model is also extensible, e.g., simple submodels of detailed properties can be made more complex without altering the overall structure.
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| 9. |
- Fritzson, Dag, et al.
(author)
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Rolling Bearing Simulation on MIMD Computers
- 1997
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In: The international journal of high performance computing applications. - : Sage Publications. - 1094-3420 .- 1741-2846. ; 11:4, s. 299-313
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Journal article (peer-reviewed)abstract
- Rolling bearing simulations are very computationally in tensive. Serial simulations may take weeks to execute, and there is a need to use the potential of parallel comput ing. The specific structure of the rolling bearing problem is used to develop suitable scheduling strategies. The authors discuss the system of stiff ordinary differential equations arising from a bearing model and show how to numerically solve these ordinary differential equations on parallel computers. Benchmarking results are presented for two test cases on three platforms.
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| 10. |
- Fritzson, Peter, et al.
(author)
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High-level mathematical modeling and programming in Scientific Computing
- 1995
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In: IEEE Software. - : IEEE. - 0740-7459 .- 1937-4194. ; 12:4, s. 77-87
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Journal article (peer-reviewed)abstract
- Scientific computing and advanced mechanical analysis demand high-level support for modeling and solving complex equations. To meet this need, the authors designed ObjectMath and applied it to real problems in machine-element analysis
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