Interactive visualization of 3D mantle convection

The current availability of thousands of processors at many high performance computing centers has made it feasible to carry out, in near real time, interactive visualization of 3D mantle convection temperature fields, using grid configurations having 10–100 million unknowns. We will describe the technical details involved in carrying out this endeavor, using the facilities available at the Laboratory of Computational Science and Engineering (LCSE) at the University of Minnesota. These technical details involve the modification of a parallel mantle convection program, ACuTEMan; the usage of client–server socket based programs to transfer upwards of a terabyte of time series scientific model data using a local network; a rendering system containing multiple nodes; a high resolution PowerWall display, and the interactive visualization software, DSCVR. We have found that working in an interactive visualizastion mode allows for fast and efficient analysis of mantle convection results.     

Ubiquitous interactive visualization of 3D mantle convection using a web-portal with Java and Ajax framework

We have developed a new strategy and espouse a novel paradigm for large-scale computing and real-time interactive visualization. This philosophy calls for intense interactive sessions for a couple of hours at a time at the expense of storing data on many disk drives during regular or heroic runs on massively parallel systems. We have already carried out successfully real-time volume-rendering visualization by employing hundreds of processors for a grid with over 25 million unknowns. Both Cartesian and spherical 3D mantle convection are visualized. The volume-rendered images are viewed on a large display device, with many panels holding around 13 million pixels. We will employ a software strategy involving an hierarchical rendering service, which will have as software an Ajax interface for interactive visualization of large data sets on many different platforms from desktop PC’s to hand-held devices, such as the OQO and the Nokia N-800. An option for stereo viewing is also implemented. We have installed a user interface as web application, using Java and Ajax framework in order to achieve over the Internet reasonable accessibility to our ongoing runs. Our goal is to expand the array of interactive devices, which will make it feasible to carry out ubiquitous visualization and monitoring of large-scale simulations or onsite events and to allow for collaborations across oceans.     

Current Trends and Demands in Visualization in the Geosciences

Geosciences, along with many other disciplines in science and engineering, faces an exponential increase in the amount of data generated from observation, experiment and large-scale, high-resolution 3-D numerical simulations. In this communication we describe the fundamentals of visualization necessary to meet these challenges. We present several alternative methodologies such as 2D/3D feature extraction, segmentation methods, and flow topology, to help better understand the physical structure of the data. We use AMIRA from TGS to demonstrate our concepts. Examples are drawn from fields in computational fluid dynamics, 3-D mantle convection and seismic tomography. Finally, we present our perspective on the future of visualization.     

An Approach to a Visual Language for Convective Fluid Flows: Visualization of Geophysical Simulations

It was known that deep within numbers and binary data from simulations of geophysical convective flows resided various patterns. Two models of convective fluid flows were being considered. One was a model of two-dimensional (768 × 256) air convection with finite Prandtl number of one and Rayleigh number of 10⁸?10¹⁰, and another was a model of three-dimensional (up to 120 × 120 × 90) mantle convection with infinite Prandtl number and Rayleigh number of 10⁶?10⁸. Clearly, phenomena existed which superceded each individual dimensionless computer model to provide a piece of information regarding actual fluid flows. The problem was how to find, prove, and communicate these patterns and phenomena for convection simulations with gigabytes of data. In a search for such an analytical and communicative tool, the alternative of visualization was considered. The need for visualization was recognized and discussed. Then, utilizing both two- and three-dimensional models of high Rayleigh number convection, basic techniques of style and content were developed. Applications of the visualization techniques were designed utilizing IBM’s Data Explorer in order to create communicative images and movies, and after the applications, the problems of data storage and transfer became apparent. Throughout the process though, it became clear how important the language of vision actually could be in the geophysics community. In a field in which words such as plumes and internal waves have in ways replaced mathematics as the basic language for science, there is a need for another resource, another language-the visualization of convective fluid flows.     

Interactive Web-Based Map: Applications to Large Data Sets in the Geosciences

Current advances in computer hardware, information technology and data collection techniques have produced very large data sets in a wide variety of scientific and engineering disciplines. We must harness this opportunity to visualize and extract useful information from geophysical and geological data. We have taken the task of data mining by implementing a map-like approach over a web server for interrogating the data, using a client-server paradigm. The spatial-data is mapped onto a two-dimensional grid from which the user (client) can quiz the data with the map-interface as a user extension. The data is stored on the server, while the computational gateway separating the client and the server can be the front-end of an electronic publication, electronic classroom, a survey, or an e-business. We have used a combination of Java, Java3D, and Perl for processing the data and communicating between the client and the server. The user can interrogate the geospatial data over any particular region with arbitrary dimensions and then receive back relevant statistical analysis, such as the histogram plots and local statistics. We have applied this method for the following data sets: (1.) distribution of prime numbers (2.) two-dimensional mantle convection (3.) three-dimensional mantle convection (4.) high-resolution satellite reflectance data over multiple wavelengths (5.) molecular dynamics describing the flow of blood in narrow vessels. Using the map-interface, one can actually interrogate this data over the Internet.     

Visualization of time-dependent dynamics of postglacial rebound

Postglacial rebound is a major geological process which plays an important role in many areas in the earth sciences. Up to now, most of the images derived from studies of the glacial isostatic adjustment phenomenon have been concerned with surface signatures, such as the uplift and gravity anomalies and not much attention has been paid on the dynamical responses in the mantle. We will make use of the 3D visualization package Amira to depict both the external and internal deformation histories of the transient viscoelastic flow inside the mantle induced by postglacial uplift. Of particularly great interest are the transient displacement fields and shear heating inside the mantle. This same visualization technology can be brought to bear in the future for visualizing tsunami waves in ocean basins excited by earthquakes, volcanic eruptions and InSAR images. We have also integrated the visualization results into the Google Earth virtual globe by combining this scheme with the Amira package to provide a better geographical and dynamical context.     

Interactive Statistical Analysis of Complex Mantle Flows with the Web

Up to now, all of the figures in mantle convection literature have been presented in a static manner, where the fields at one scale are shown on a printed page . This is no longer possible with the spatial resolution increasing at an ever rising clip and the appearance of the issue of multi-scale structures. Because of the onslaught of data-flooding and the growing complexity of strongly time-varying physical fields from compressible mantle convection, such as the adiabaticity, and other thermo dynamical heating functions, we can no longer afford to display and look at the results in the same static way as in a book. We have developed a new approach for interrogating data coming out from numerical simulations. This is based on an interactive two-dimensional map which is used over the WEB with a client-server paradigm. We have applied this to investigate mantle convection flows in both two-and three-dimensional situations. The distributions of thermal anomalies found are no longer Gaussian but sometimes have long tails, especially near the edges of plume heads. The same is also found for the distribution of mechanical heating, which can be quite skewed. Our experiences with this new interactive mode of data-query have shown both the educational and scientific importance of using the world wide web media to quiz handily the data taken from large-scale numerical simulations.     

Parallel visualization of seismic wave propagation

Today parallel visualization of massive datasets from observation and numerical simulation of seismic waves is one of the major goals of geoscience community. A majority of these datasets are time-varying volume data (TVVD), also known as 4D field data. The difficulty of visualizing them on distributed parallel system mainly lies in the algorithm designing for distributed preprocessing of raw datasets, hierarchical point-to-point or collective communication implementation based on distributed data allocation, synchronous volume rendering techniques. In this work we present viable solutions for preprocessing of raw data sets, novel algorithms of parallel rendering and display matrix. Our main objective is focused on the parallel visualization of results coming from full 4D seismic wave propagation simulations.     

WEB-IS (integrated system): an overall view

WEB-IS, Web-based Integrated System, allows remote, interactive visualization of large-scale 3-D data over the Internet, along with data analysis and data mining. In this paper, we discuss the overall structure of WEB-IS. Up until now we have developed three sub-modules geared towards geophysical problems. WEB-IS1 allows geoscientists to navigate through their 3-D geophysical data, such as seismic structures or numerical simulations, and interactively analyze the statistics or apply data-mining techniques, such as cluster analysis. WEB-IS2 lets a user control Amira (a powerful 3-D visualization package) remotely and analyze, render and view large datasets across the Internet. WEB-IS3 is an imaging service that enables the user to control the scale of features to view through interactive zooming. In the near future, we propose to integrate the three components together through a middleware framework called NaradaBrokering (iNtegrated Asynchronous Real-time Adaptive Distributed Architecture, a distributed messaging infrastructure that can be used to intelligently route data between the originators and registered consumers) without regard for time or location. As a result, WEB-IS will improve its scalability and acquire properties of fault-tolerance. WEB-IS uses a combination of Java, C++, and through the use of NaradaBrokering will seamlessly integrate the server-side processing and user interaction utilities on the client. The server takes care of the processor intensive tasks, such as visualization and data mining, and sends either the resulting bitmap image or statistical results to the middleware across the Internet for viewing. WEB-IS is an easy-to-use service, which will eventually help geoscientists collaborate from different sites in a natural manner. It will be very useful in the next 10 years because of the increasing number of space missions and geophysical campaigns.     

The Problem of Viscoelastic Relaxation of the Earth Solved by a Matrix Eigenvalue Approach Based on Discretization in Grid Space

Viscoelasticity is a geophysical process which operates over intermediate timescales between a few years to millions of years, depending on the ambient thermal conditions of the self-gravitating spherical planet. Topography undulations with time represent geological signatures to both the internal and external loading processes, such as post-glacial rebound, volcanic eruptions, sedimentary loading, meteoritic impacts and mountain building. The span of relaxation timescales or relaxation spectrum in a viscoelastic spherical body has traditionally been determined by employing the Laplacian transform method and the correspondence principle relating the elastic solution to its viscoelastic counterpart. We have devised a novel approach based on the method of lines in which the equations at each angular order in the spherical harmonic expansion are discretized in the radial co-ordinate. The finite-dimensional space spanned by the discretized points in the radial direction of the planetary model then forms the basis of a matrix Eigenvalue problem. The Eigenvalues can be computed very fast because of the availability of public domain software. We can, for instance, compute the entire range of viscoelastic relaxation with computational times from 0.05 to 50 sec using only 30 to 300 radial grid points. The models can have both realistic density and elastic parameter profiles, derived from seismology. We show results here for complicated viscosity profiles with an asthenosphere in the upper mantle and a viscosity hill in the middle portion of the lower mantle. Because of the rapidity of the code, we may use this new method for exploring non-linear inversion problems by parameter sweeping.     

Visualization and Analysis of Mixing Dynamical Properties in Convecting Systems with Different Rheologies

We analyzed and compared the mixing properties of 2-D mantle convection models. Two rheologically different models, Newtonian and non-Newtonian (power-law), were considered with both the line and field methods. The line method is based on monitoring of passive particles joined into lines, while the field method relies on the advection of a passive scalar field. Both visual and quantitative estimates revealed that the efficiency of the Newtonian mixing is greater than the non-Newtonian. A heterogeneity placed in the non-Newtonian convection forms horizontal structures, which may persist for at least 1 Ga on the upper-mantle scale. In addition, the non-Newtonian medium reveals a lesser amount of stretching of the lines than the Newtonian material. The rate of the Newtonian stretching fits well with an exponential dependence with time, while the non-Newtonian rheology shows the stretching rate close to a power-law dependence with time. In the Newtonian medium the heterogeneity is reorganized into two unstable vertical columns, while the non-Newtonian mixing favors horizontal structures. In the latter case, these structures are sufficiently stable in both the temporal and spatial planes to explain the mantle geochemical and geophysical heterogeneities. Due to the non-linear character of power-law rheology, the non-Newtonian medium offers a “natural” scale-dependent resistance to deformation, which prevents efficient mixing at the intermediate length scales.     

Secondary upwelling instabilities developed in high Rayleigh number convection: Possible applications to hot spots

We have conducted numerical experiments for mantle convection in an axisymmetrical spherical-shell geometry from Rayleigh numbers ranging from three million to 10 billion for a purely basal heating configuration. We focus on the development of secondary instabilities developed from plumes and compare them with laboratory experiments by Skilbeck and Whitehead (1978) and Whitehead, (1982). For Rayleigh numbers between around thirty million to one billion, a string of these secondary instabilities can develop from a single plume. Analysis of the spectrum of wavelength associated with the fold instabilities shows that there is a window in the Rayleigh number between around ten million and one bilion where these secondary folding instabilities would develop. These results, when applied to the upper mantle, may explain the formation of hot-spots in a turbulently convecting upper-mantle with a Rayleigh number greater than ten million.     

我国纺织工业东、西部合作与产业转移

我国纺织工业主要分布于沿海地区。随着沿海地区经济发展 ,沿海地区生产要素的价格 ,特别是劳动力价格的上涨 ,使得沿海地区纺织工业的传统优势在逐渐丧失 ,纺织工业呈现出向西部地区转移的趋势 ,特别是纺织初加工业。纺织工业向西部地区转移的原因主要是 :来自国内外的竞争压力 ;区域分工与协作的需要 ;国家宏观政策的影响以及西部地区所具有的资源和劳动力优势。从纺织工业转移的前景看 ,棉纺工业向西部地区转移的趋势较为明显 ,而毛纺和化纤工业近期向西部地区转移的趋势并不明显。     

Visualization of tsunami waves with Amira package

In recent years numerical investigations of tsunami wave propagation have been spurred by the magnitude 9.3 earthquake along the Andaman–Sumatra fault in December, 2004. Visualization of tsunami waves being modeled can yield a much better physical understanding about the manner of wave propagation over realistic seafloor bathymetries. In this paper we will review the basic physics of tsunami wave propagation and illustrate how these waves can be visualized with the Amira visualization package. We have employed both the linear and nonlinear versions of the shallow-water wave equation. We will give various examples illustrating how the files can be loaded by Amira, how the wave-heights of the tsunami waves can be portrayed and viewed with illumination from light sources and how movies can be used to facilitate physical understanding and give important information in the initial stages of wave generation from interaction with the ambient geological surroundings. We will show examples of tsunami waves being modeled in the South China Sea, Yellow Sea and southwest Pacific Ocean near the Solomon Islands. Visualization should be a part of any training program for teaching the public about the potential danger arising from tsunami waves. We propose that interactive visualization with a web-portal would be useful for understanding more complex tsunami wave behavior from solving the 3-D Navier–Stokes equation in the near field.     

Clustering and visualization of earthquake data in a grid environment

We present a web client-server service WEB-IS, which we have developed for remote analysis and visualization of seismic data consisting of both small magnitude events and large earthquakes. We show that the problem-solving environment (PSE) intended for prediction of large magnitude earthquakes can be based on this WEB-IS idea. The clustering schemes, feature generation, feature extraction techniques and rendering algorithms form a computational framework of this environment. On the other hand, easy and fast access both to the seismic data distributed among distant computing resources and to computational and visualization resources can be realized in a GRID framework. We discuss the usefulness of NaradaBrokering (iNtegrated Asynchronous Real-time Adaptive Distributed Architecture) as a middleware, allowing for flexibility and high throughput for remote visualization of geophysical data. The WEB-IS functionality was tested both on synthetic and the actual earthquake catalogs. We consider the application of similar methodology for tsunami alerts.     

Unification and the policy predicament in Germany

We argue that wages have increased so far ahead of labour productivity in east Germany as to produce a problem that will continue to hound German policy-makers for the next two decades. Despite rapid rates of capital accumulation (around 9%) and growth (around 5%) in east Germany over the coming 10 years, our estimates show that even if wage catch-up decelerates greatly, as long as it continues, the rate of unemployment in the east will still be twice as high as in the west in another 10 years. Alternatively, if wage discipline forces the eastern unemployment rate to come down to the western level, wage differentials will widen substantially over these next 10 years. Thus serious problems loom ahead.     

Visualization of multi-scale dynamics of hydrous cold plumes at subduction zones

Recent increases in the computational power of high-performance computing systems have led to a large gap between the high-resolution runs of numerical simulations—typically approaching 50–100 million tracers and 1–5 million grid points in two dimensions—and the modest resolution of 1–2 million pixels for conventional display devices. This technical problem is further compounded by the variety of fields produced by numerical simulations and the limited bandwidth available through the Internet in the course of collaborative ventures. We have developed a visualization system using the paradigm of web-based inquiry to address these mounting problems. We have employed, as a case study, a problem involving two-dimensional multi-scale dynamics of hydrous cold plumes at subduction zones. A Lagrangian marker method, in which the number of markers varies dynamically, is used to delineate the many different fields, such as temperature, viscosity, strain, and chemical composition. We found commercially available software to be insufficient for our visualization needs and so we were driven to develop a new set of tools tailored to high-resolution, multi-aspect, multi-scale simulations, and adaptable to many other applications in which large datasets involving tens of millions of tracers with many different fields are prevalent. In order to address this gap in visualization techniques, we have developed solutions for remote visualization and for local visualization. Our remote visualization solution is a web-based, zoomable image service (WEB-IS) that requires minimal bandwidth while allowing the user to explore our data through time, across many thermo–physical properties, and through different spatial scales. For local visualization, we found it optimal to use bandwidth-intensive, high-resolution display walls for performing parallel visualization in order to best comprehend the causal and temporal relationships between the multiple physical and chemical properties in a simulation.     

Evaluating R&D performance of EU countries using categorical DEA

Over the coming decade, Research and Development (R&D) performance will be the key component of bringing innovation and the determinant of global competitiveness of nations. Therefore, this paper presents categorical Data Envelopment Analysis (DEA) for evaluating R&D performance of European Union (EU) countries. We utilise the output-oriented constant returns to scale (CRS) and variable returns to scale (VRS) DEA models with categorical data, namely, CAT-O-C and CAT-O-V models. In addition to DEA based framework, to examine the relationship between R&D performance and political-regulatory-economic situation of the countries; three research hypotheses are stated and their results are analysed. Policy implications about R&D activities can be derived for EU countries from the findings of this study.     

3D printing,international trade,and FDI

We analyze the relationship between 3D printing technology, the volume of trade, and the structure of foreign direct investment (FDI). We present a standard trade model with firm-specific heterogeneity into which we include 3D printing as a technology choice for foreign direct investment. The model generates three predictions. First, 3D printers are introduced in areas with high economic activity that face high transport costs. Second, technological progress in 3D printing leads to FDI dependent on traditional techniques gradually being replaced by FDI based on 3D printing. Third, with wider adoption, further technological progress in 3D printing leads to a gradual replacement of international trade. Empirical evidence focusing on the sectors with the highest rates of adoption supports the first hypothesis, while evidence from a case study supports the second and third. Our results suggest that the traditional strategy of poor countries for export-led industrialization is threatened by the widespread adoption of 3D printing that replaces international trade.     

Demographic trends and international capital flows in an integrated world

This paper examines the impact of projected demographic trends on international capital flows. The analysis builds upon a ten-region overlapping generations' model of the world economy where capital is mobile across regions. Results show that, over the first half of the century, emerging regions will finance the demand of capital coming from the developed world where population aging is relatively advanced. In particular, the findings suggest that in the coming decades China will be the world's main creditor region. However, in the second half of the century, India will take over this leading position because of the predicted decline in the Chinese labor force. An additional analysis demonstrates that the economic consequences of demographic changes depend on the degree of capital market integration between regions.