rpanel: Simple Interactive Controls for R Functions Using the tcltk Package

In a variety of settings it is extremely helpful to be able to apply R functions through buttons, sliders and other types of graphical control. This is particularly true in plotting activities where immediate communication between such controls and a graphical display allows the user to interact with a plot in a very effective manner. The tcltk package provides extensive tools for this and the aim of the rpanel package is to provide simple and well documented functions which make these facilities as accessible as possible. In addition, the operations which form the basis of communication within tcltk are managed in a way which allows users to write functions with a more standard form of parameter passing. This paper describes the basic design of the software and illustrates it on a variety of examples of interactive control of graphics. The tkrplot system is used to allow plots to be integrated with controls into a single panel. An example of the use of a graphical image, and the ability to interact with this, is also discussed.

Analysis of (iso)surface reconstructions: Quantitative metrics and methods

Due to sampling processes volumetric data is inherently discrete and most often knowledge of the underlying continuous model is not available. Surface rendering techniques attempt to reconstruct the continuous model, using isosurfaces, from the discrete data. Therefore, it natural to ask how accurate the reconstructed isosurfaces are with respect to the underlying continuous model. A reconstructed isosurface may look impressive when rendered ( photorealism ), but how well does it reflect reality ( physical realism )?;The users of volume visualization packages must be aware of the short-comings of the algorithms used to produce the images so that they may properly interpret, and interact with, what they see. However, very little work has been done to quantify the accuracy of volumetric data reconstructions. Most analysis to date has been qualitative. Qualitative analysis uses simple visual inspection to determine whether characteristics, known to exist in the real world object, are present in the rendered image. Our research suggests metrics and methods for quantifying the physical realism of reconstructed isosurfaces.;Physical realism is a many faceted notion. In fact, a different metric could be defined for each physical property one wishes to consider. We have defined four metrics--Global Surface Area Preservation (GSAP), Volume Preservation (VP), Point Distance Preservation (PDP), and Isovalue Preservation (IVP). We present experimental results for each of these metrics and discuss their validity with respect to those results.;We also present the Reconstruction Quantification (sub)System (RQS). RQS provides a flexible framework for measuring physical realism. This system can be embedded in existing visualization systems with little modification of the system itself. Two types of analysis can be performed; reconstruction analysis and algorithm analysis. Reconstruction analysis allows users to determine the accuracy of individual surface reconstructions. Algorithm analysis, on the other hand, allows developers of visualization systems to determine the efficacy of the visualization system based on several reconstructions

Porting a visualization package from IRIX to NT : what will I get, what will I pay?

We discuss our experiences in porting a moderately large scientific visualization environment from IRIX to NT~4.0. Two porting strategies have been taken: a port via a POSIX emulation layer and a native NT port. POSIX compliant code can be ported to NT with relatively little effort if the code adheres to general accepted programming principles, such as modularity and encapsulation. The performance of a modern 3D Wintel machine is quite satisfactory for a variety of scientific desktop tasks. We have compared the performance of a 2 CPU Dell OptiPlex with FireGL 4000 graphics option to various SGI desktop workstations

rpanel: Simple interactive controls for R functions using the tcltk package

In a variety of settings it is extremely helpful to be able to apply R functions through buttons, sliders and other types of graphical control. This is particularly true in plotting activities where immediate communication between such controls and a graphical display allows the user to interact with a plot in a very effective manner. The tcltk package provides extensive tools for this and the aim of the rpanel package is to provide simple and well documented functions which make these facilities as accessible as possible. In addition, the operations which form the basis of communication within tcltk are managed in a way which allows users to write functions with a more standard form of parameter passing. This paper describes the basic design of the software and illustrates it on a variety of examples of interactive control of graphics. The tkrplot system is used to allow plots to be integrated with controls into a single panel. An example of the use of a graphical image, and the ability to interact with this, is also discussed

Simulation modelling and visualisation: toolkits for building artificial worlds

Simulations users at all levels make heavy use of compute resources to drive computational simulations for greatly varying applications areas of research using different simulation paradigms. Simulations are implemented in many software forms, ranging from highly standardised and general models that run in proprietary software packages to ad hoc hand-crafted simulations codes for very specific applications. Visualisation of the workings or results of a simulation is another highly valuable capability for simulation developers and practitioners. There are many different software libraries and methods available for creating a visualisation layer for simulations, and it is often a difficult and time-consuming process to assemble a toolkit of these libraries and other resources that best suits a particular simulation model. We present here a break-down of the main simulation paradigms, and discuss differing toolkits and approaches that different researchers have taken to tackle coupled simulation and visualisation in each paradigm

Interactive Teaching Tools for Spatial Sampling

The statistical analysis of data which is measured over a spatial region is well established as a scientific tool which makes considerable contributions to a wide variety of application areas. Further development of these tools also remains a central part of the research scene in statistics. However, understanding of the concepts involved often benefits from an intuitive and experimental approach, as well as a formal description of models and methods. This paper describes software which is intended to assist in this understanding. The role of simulation is advocated, in order to explain the meaning of spatial correlation and to interpret the parameters involved in standard models. Realistic scenarios where decisions on the locations of sampling points in a spatial setting are required are also described. Students are provided with a variety of sampling strategies and invited to select the most appropriate one in two different settings. One involves water sampling in the lagoon of the Mururoa Atoll while the other involves sea bed sampling in a Scottish firth. Once a student has decided on a sampling strategy, simulated data are provided for further analysis. This extends the range of teaching activity from the analysis of data collected by others to involvement in data collection and the need to grapple with issues of design. It is argued that this approach has significant benefits in learning.

QT grafičko korisničko sučelje u Pythonu

U ovome radu opisana je biblioteka Qt, višeplatformski radni okvir otvorenog koda za izradu grafičkih korisničkih sučelja računalnih programa. Pruženi su uvid u povijest nastanka Qt-a, njegova svojstva, tri osnovne značajke (apstrakcija od izrade grafičkog sučelja, signali i slotovi i metaobjektni prevoditelj) i jezična poveznica koja omogućuje korištenje Qt biblioteke u programskom jeziku Python. Primjenom jezičnih poveznica programer ne mora poznavati programski jezik u kojemu je biblioteka izvorno napisana jer poveznica sadrži objekte i metode ili funkcije biblioteke napisane u programeru poznatom jeziku. Predstavljene su tri druge široko rasprostranjene višeplatformske biblioteke otvorenog koda za izradu sučelja računalnih programa: GTK+, Kivy i wxWidgets. Pritom su istaknuta svojstva po kojima se te biblioteke razlikuju od Qt-a i ona koja su im zajednička. Na kraju je predstavljen primjer programa napisanog u Pythonu pomoću Qt biblioteke koji omogućuje učitavanje i prikaz slika, njihovu obradu koristeći skriptirane filtere te pregled i pohranu izmijenjene slike. Filteri obrađuju slike primjenom OpenCV biblioteke.This paper describes the Qt library, an open-source, cross-platform framework used for developing graphical user interfaces of computer programs. An insight is given into the history of creation, features, three principal properties of Qt (abstraction of the graphical user interface, signals and slots and the metaobject compiler), and a language binding which allows the usage of Qt in Python programming language. Language bindings relieve the programmer of the need to learn the language in which a library is originally written as the binding contains objects and methods or functions of the library written in a language known to the programmer. Three other widespread open-source cross-platform libraries for graphical user interface development are presented: GTK+, Kivy, and wxWidgets. Features which differ Qt from these libraries are emphasized as well as features which Qt has in common with them. Finally, a program example written in Python using Qt is demonstrated, which allows loading and viewing images, their manipulation using scripted filters, previewing and saving the altered image. Filters perform image processing using the OpenCV library

Hayaku : designing and optimizing finely tuned and portable interactive graphics with a graphical compiler

International audienceAlthough reactive and graphically rich interfaces are now mainstream, their development is still a notoriously difficult task. This paper presents Hayaku, a toolset that supports designing finely tuned interactive graphics. With Hayaku, a designer can abstract graphics in a class, describe the connections between input and graphics through this class, and compile it into runnable code with a graphical compile chain. The benefits of this approach are multiple. First, the frontend of the compiler is a rich standard graphical language that designers can use with existing drawing tools. Second, manipulating a data flow and abstracting the low-level run-time through a front-end language makes the transformation from data to graphics easier for designers. Third, the graphical interaction code can be ported to other platforms with minimal changes, while benefiting from optimizations provided by the graphical compiler

Electromagnetic Scattering Characteristics of Composite Targets and Software Development Based on PO Algorithm

Physical optics (PO) algorithm is a high-frequency electromagnetic (EM) algorithm, which is widely used to solve the EM scattering problems of electrically large composite targets. Due to the PO algorithm only considers the induced current in the bright region irradiated by EM wave, the computational memory and time consumption are superior than other high-frequency algorithms, and the calculation accuracy is pretty fine. Based on the PO algorithm, this thesis focuses on the occlusion judgement of PO algorithm and its application in composite targets. The main contents of this thesis are as follows: 1. The occlusion judgement software system for PO algorithm is developed. The main function of this software is to judge the bright region of the target under the irradiation of EM wave. This software uses two judgement methods: ray tracing method based on CPU and Z-Buffer method based on CPU and GPU. Moreover, due to the compromise between patch size and patch number, both methods have errors at the edge of bright and shadow regions. This thesis discusses the error and reduces it. 2. Based on PO algorithm, the EM scattering characteristics of targets covered by plasma sheath are discussed. We simulate the plasma sheath flow field data of hypersonic vehicle by FASTRAN software, compare and analyze the plasma sheath electron number density at different flight heights and speeds. On this basis, the bistatic RCS of hypersonic vehicle head-on irradiation under different flight heights and speeds is calculated by using the PO algorithm of layered medium. 3. SAR image simulation of tree ground composite target is carried out based on PO algorithm and Non-Uniform Fast Fourier Transform (NUFFT) method. Firstly, we introduce the geometric modeling and EM parameter modeling of tree ground composite target, and the scattering characteristics of tree ground composite target are obtained by using PO algorithm. Finally, the scattering field of the target is processed by NUFFT method, and the SAR simulation images of multiple trees scene are obtained