The IDX data format provides efficient, cache oblivious, and progressive access to large-scale scientific datasets by storing the data in a hierarchical Z (HZ) order. data stored in IDX format can be visualized in an ...
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The IDX data format provides efficient, cache oblivious, and progressive access to large-scale scientific datasets by storing the data in a hierarchical Z (HZ) order. data stored in IDX format can be visualized in an interactive environment allowing for meaningful explorations with minimal resources. This technology enables real-time, interactive visualization and analysis of large datasets on a variety of systems ranging from desktops and laptop computers to portable devices such as iPhones/iPads and over the web. While the existing ViSUS API for writing IDX data is serial, there are obvious advantages of applying the IDX format to the output of large scale scientific simulations. We have therefore developed PIDX - a parallel API for writing data in an IDX format. With PIDX it is now possible to generate IDX datasets directly from large scale scientific simulations with the added advantage of real-time monitoring and visualization of the generated data. In this paper, we provide an overview of the IDX file format and how it is generated using PIDX. We then present a data model description and a novel aggregation strategy to enhance the scalability of the PIDX library. The S3D combustion application is used as an example to demonstrate the efficacy of PIDX for a real-world scientific simulation. S3D is used for fundamental studies of turbulent combustion requiring exceptionally high fidelity simulations. PIDX achieves up to 18 GiB/s I/O throughput at 8,192 processes for S3D to write data out in the IDX format. This allows for interactive analysis and visualization of S3D data, thus, enabling in situ analysis of S3D simulation.
Isoline generating is often used in reservoir simulation, but the speed of data processing is likely to become slowly while the number of data is enormous. During the isoline generating, isoline tracing takes most of ...
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Isoline generating is often used in reservoir simulation, but the speed of data processing is likely to become slowly while the number of data is enormous. During the isoline generating, isoline tracing takes most of the time. In order to satisfy the requirement of real-time, an isoline tracing algorithm with CUDA is designed in this paper. In the algorithm designed here, equivalent points are stored in texture memory, and took an indexed array instead of link list structure. In order to make full use of multi-thread in GPU, a new method for tracing the isoline is designed in this paper. The experiment shows that the algorithm is high effective even if the number of data is enormous.
nSpace2 is an innovative visual analytics tool that was the primary platform used to search, evaluate, and organize the data in the VAST 2011 Mini Challenge #3 dataset. nSpace2 is a web-based tool that is designed to ...
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nSpace2 is an innovative visual analytics tool that was the primary platform used to search, evaluate, and organize the data in the VAST 2011 Mini Challenge #3 dataset. nSpace2 is a web-based tool that is designed to facilitate the back-and-forth flow of the multiple steps of an analysis process, including search, data triage, organization, sense-making, and reporting. This paper describes how nSpace2 was used to assist every step of the analysis process for this VAST challenge.
Permission-based security models use a computer security technique that allows the administrator and operating system to restrict applications to access specific resources. The restrictions used in this model are not ...
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Permission-based security models use a computer security technique that allows the administrator and operating system to restrict applications to access specific resources. The restrictions used in this model are not designed by the users, but instead are designed by developers or administrators. Therefore, the user's system security is dependent on the user's belief that the developers and administrators are legitimate, which can be easily exploited by malicious developers. In this paper, we perform a high-level contextual analysis and an exploration of Android applications based on their implementation of permission-based security models by applying network visualization techniques and clustering algorithms. Throughout the analysis, we discover several phenomena that verify past research, and new potentials in permission-based security models that may provide additional security to the users.
Parallel coordinates is a powerful visualization method for the exploration of multi-dimensional dataset, but the crowded poly line make it hard to find pattern, although another view such as scatter plot can be linke...
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Parallel coordinates is a powerful visualization method for the exploration of multi-dimensional dataset, but the crowded poly line make it hard to find pattern, although another view such as scatter plot can be linked. It is meaningful to find suitable way to assign point to poly line. We presented a simple method to assign point for different line segment, the application of our method shows that it is feasible and beneficial in the process of dataanalysis.
Complex data is usually represented through signatures, which are sets of features describing the data content. Several kinds of complex data allow extracting different signatures from an object, representing compleme...
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Complex data is usually represented through signatures, which are sets of features describing the data content. Several kinds of complex data allow extracting different signatures from an object, representing complementary data characteristics. However, there is no ground truth of how balancing these signatures to reach an ideal similarity distribution. It depends on the analyst intent, that is, according to the job he/she is performing, a few signatures should have more impact in the data distribution than others. This work presents a new technique, called Visual Signature Weighting (ViSW), which allows interactively analyzing the impact of each signature in the similarity of complex data represented through multiple signatures. Our method provides means to explore the tradeoff of prioritizing signatures over the others, by dynamically changing their weight relation. We also present case studies showing that the technique is useful for global dataset analysis as well as for inspecting subspaces of interest.
Feature visualization plays an important role in visualization of complicated flows because it can highlight the feature of the flows with a simplified representation. The traditional feature visualization methods may...
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Feature visualization plays an important role in visualization of complicated flows because it can highlight the feature of the flows with a simplified representation. The traditional feature visualization methods may exact some important features in flow field imprecisely due to the lack of the knowledge and the experience of the user. This paper gives a particle-based visualization system which is developed with the application of the interactive fuzzy feature extraction and interactive visual analysis theories. To obtain a more precise feature extraction, we have proposed an interactive fuzzy feature description language (FFDL) and an interactive fuzzy feature extraction algorithm. Based on the work before, we introduced the proportion ration for different rules and optimized our algorithm in practice further by communicating with specific researchers and doing lots of experiments. The further experiments show that our method can not only make full use of the ability of the user to extract the features precisely, but also reflect the uncertainty of the numerical simulation data.
This paper proposes a new approach to validating and visualising cluster structure by combining fuzzy membership functions and spectral clustering. By modifying the Visual Cluster Validity algorithm (VCV) to use an ex...
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This paper proposes a new approach to validating and visualising cluster structure by combining fuzzy membership functions and spectral clustering. By modifying the Visual Cluster Validity algorithm (VCV) to use an external fuzzy membership function as the distance measure and using sum of cluster membership as the sorting function, computational experiments on both the Zelnik-Manor synthetic and UCI real datasets show the proposed method, SpecVCMV, more clearly identifies the underlying cluster structure in the data.
This paper conducts analysis on the metadata information of shared Earth System Science data of China Scientific data Sharing Project(SDSP) published online by Portal of Chinese Science and Technology Resource. Highfr...
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This paper conducts analysis on the metadata information of shared Earth System Science data of China Scientific data Sharing Project(SDSP) published online by Portal of Chinese Science and Technology Resource. Highfrequency keywords are extracted from the metadata, keyword clusters are formed by means of co-occurrence matrix and K-core analysis, and then network visualization is made by Pajek software. This research reveals the field characteristics of the data through analyzing the keywords network structure, make conclusion on the hot acquisition spots of data in Earth System Science field shared on SDSP.
The published studies of regression testing methods often contain many of the hallmarks of high quality empirical research. Beyond features like clear descriptions of the methodology and the visualization and statisti...
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The published studies of regression testing methods often contain many of the hallmarks of high quality empirical research. Beyond features like clear descriptions of the methodology and the visualization and statistical analysis of the data sets, certain papers in this field also provide some of the artifacts used in and/or produced by the experiments. Yet, the limited industrial adoption of regression testing techniques is due in part to a lack of comprehensive empirical evaluations. Moreover, the regression testing community has not achieved a level of experimental reproducibility that would fully establish it as a science. After identifying the challenges associated with evaluating regression testing methods, this paper advocates a way forward involving a mutually beneficial increased sharing of the inputs, outputs, and procedures used in experiments.
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