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.     

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.     

Space–time multiresolution atomistic visualization of MgO and MgSiO3 liquid data

First-principles molecular dynamics simulations of complex material systems such as geophysically relevant oxide and silicate liquids produce massive amounts of time-varying three-dimensional data for the atomic configurations. Given the high accuracy of these data, it is desirable to extract as much information hidden in the data as possible. In this paper, we elaborate on our recently proposed scheme to support interactive visualization at space–time multiresolution of the atomistic simulation data. Instead of just focusing on direct rendering of the given data, additional data (containing more quantitative and qualitative information) that usually have to be extracted by some other means are extracted and rendered on the fly. This allows us to gain better insight into the global as well as local spatio-temporal behavior of the data in the context of bonding, radial distribution, atomic coordination, clustering, structural stability and distortion, and diffusion. We illustrate such visualization for the simulation data on the liquid phases of MgO and MgSiO₃—the two most abundant components of Earth’s mantle. Our analysis shows that the structure and dynamics of both liquids change substantially with compression, with no discernible effects of temperature in most cases.     

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.     

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.     

On the possibility of an inverse relationship between tax rates and government revenues

When Arthur Laffer and other ‘supply side advocates’ plot total tax revenue as a function of a particular tax rate, they draw an upward-sloping segment called the normal range, followed by a downward-sloping segment called the prohibitive range. A brief literature review indicates that tax rates on the prohibitive range in theoretical and empirical models have been the result of particularly high tax rates, high elasticity parameters, or both. The labor tax rate which maximizes total revenue, for example, will depend on the assumed labor supply elasticity. This paper introduces a new curve which summarizes the tax rate and elasticity combinations that result in maximum revenues, separating the ‘normal area’ from the ‘prohibitive area’. A general- purpose empirical U.S. general equilibrium model is used to plot the Laffer curve for several elasticities, and to plot the newly introduced curve using the labor tax example. Results indicate that the U.S. could conceivably be operating in the prohibitive area, but that the tax wedge or labor supply elasticity would have to be much higher than most estimates would suggest.     

Inflation and the Exchange Rate: The Role of Aggregate Demand Elasticity

This paper examines the effect of aggregate demand elasticity on the exchange rate when inflation occurs. We discover that both the source of the inflation, whether demand-pull or cost-push, and the elasticity of aggregate demand with respect to the price level, are of consequence for the exchange rate. We obtain two primary conclusions. First, the effect on the exchange rate of cost push inflation is ambiguous and is partially determined by the price level elasticity of aggregate demand. In particular, and assuming that the two examined countries have equivalent aggregate supply elasticities, we conclude that the nation with the less elastic aggregate demand function will see its currency appreciate relative to the other. Second, demand-pull inflation results in an unambiguous increase in the exchange rate but the size of that increase is partially a function of aggregate demand elasticity. Assuming again that two countries have equivalent aggregate supply elasticities, that country with the more elastic aggregate demand will experience currency appreciation.     

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.     

Volume rendering visualization of 3D spherical mantle convection with an unstructured mesh

We propose a new approach to utilize the algorithm of hardware-assisted visibility sorting (HAVS) in the 3D volume rendering of spherical mantle convection simulation results over unstructured grid configurations. We will also share our experience in using three different spherical convection codes and then taking full advantages of the enhanced efficiency of visualization techniques, which are based on the HAVS techniques and related transfer functions. The transfer function is a powerful tool designed specifically for editing and exploring large-scale datasets coming from numerical computation for a given environmental setting, and generates hierarchical data structures, which will be used in the future for fast access of GPU visualization facilities. This method will meet the coming urgent needs of real-time visualization of 3D mantle convection, by avoiding the demands of huge amount of I/O space and intensive network traffic over distributed parallel terascale or petascale architecture.     

Productivity versus elasticity: a normalized constant elasticity of substitution production function applied to historical Soviet data

This study tests the extensive growth hypothesis, which would attribute the Soviet economic slowdown to low elasticity of substitution and over-investment rather than deteriorating productivity growth. To circumvent the low availability of data, widely applicable new methods for estimating productivity and elasticity of substitution were developed based on the normalized constant elasticity of substitution (CES) production function. One is an extended version of the Solow residual calculation, and the other is a direct estimation of the time-varying parameter normalized CES production function. The application of the methods to the Soviet data showed a decreasing trend in productivity growth and a low elasticity of substitution of approximately 0.25. The results neither reject nor support the extensive growth hypothesis because of uncertainty in the interpretation of the low elasticity of substitution. The results suggest that it is reasonable to assert that both deteriorating productivity growth and low elasticity of substitution caused the Soviet economic slowdown. Further empirical studies on productivity and elasticity of substitution in the Soviet and other economies are necessary to fully understand relations between productivity growth, elasticity of substitution and economic development.     

The physical Properties of marine sediments as inferred from Wavelet Correlation Analysis

Seismic waves traveling in the water/sediment or sub-bottom sediment interface have been the subject of considerable interest in underwater acoustics in recent years. Some progress has been made in understanding the propagation and attenuation characteristics of interface waves in different geological environments. However, the generating mechanisms are poorly understood. In particular, what is the acoustic-seismic energy conversion process? As seismic waves involve both time and space parameters it should be able to relate directly the propagation characteristics of the ocean bottom interface waves to the shear properties of the sediments over the propagation area. To address these problems we have applied the wavelet correlation method (WCR) to examine the variations of bottom characteristics and their role in coupling waterborne sound into the sea bottom. To confirm the validity of the developed modeling technique, we applied the wavelet correlation analysis for synthetic seismograms and field data. In this discussion paper we present images of the first and second shear modes and the interface wave component as a function of arrival time and frequency. We also discuss the possibility of inverting phase and group velocity information directly from the wavelet cross-correlation function and propose the way of using the WCR method to predict physical dynamic parameters of marine sediments.     

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.     

With and without the tracks: how railroad access impacts gas price elasticity

Since 2011, gas prices have fallen 43%, raising the question of how different communities adjust their vehicle miles travelled. Data from the National Household Travel Survey’s EPA fuel economy database and the Energy Information Administration database are used to measure consumers’ elasticity to changes in gas prices. We find no significant difference between the price elasticity of individuals in cities with rail access and those without. Furthermore, we are able to rule out an elasticity in those with rail that is greater than 0.61, suggesting that rail access does not make consumer demand elastic.     

Housing supply elasticity in local government areas of Sydney

We report supply elasticity estimates of residential property (houses and apartments) for local government areas (LGAs) in metropolitan Sydney. Using annual data for 1991–2012, the average supply elasticity estimate across all LGAs is 0.2 for houses and 0.8 for apartments. The supply of houses is inelastic in all 43 LGAs; in contrast, apartment supply is elastic – greater than unity – in about one-third of LGAs. We develop theoretical and empirical models to explain the cross-section variation in supply elasticity across LGAs. For houses, supply elasticity is negatively related to an LGA’s population density, the time taken by a local council to process a development application and to different measures of the amount of land in an LGA that is unavailable for new housing development. In contrast to houses, variation in supply elasticity for apartments across LGAs is unrelated to any of the available regressors.     

Valuing water for Chinese industries: a marginal productivity analysis

A marginal productivity approach is developed for valuing industrial use of water and applied using data from Chinese industrial firms, where water, as well as capital, labour and raw materials, are treated as inputs to a production function. Models on price elasticity of water demand associated with the marginal productivity approach are also developed and estimated for different Chinese industrial sectors.     

The impact of public R&D investments on patenting activity: technology transfer at the U.S. Environmental Protection Agency

ABSTRACT

This paper presents estimates of the impact of public R&D on patenting activity at the U.S. Environmental Protection Agency (EPA). Using a time series of public sector agency data, we estimate the per-capita R&D elasticity of new patent applications using a knowledge production function framework model that is an expanded version of what other scholars have used with private sector data. New patent applications are an important step in the technology transfer activities of a federal agency. We estimate this elasticity to be about 2.0. This elasticity value represents an initial estimate of the impact of EPA’s R&D investments on its technology transfer activity.     

Robots and humans – complements or substitutes?

The effect of the spread of Artificial Intelligence (AI) on wages depends on both the form of aggregate production relationships and the elasticity of substitution between human and robotic labor. With a conventional production function involving labor, robots, and ordinary capital, an increase in robotic labor can have either a positive or a negative effect on wages. Alternatively, it is possible to estimate the aggregate production relationship without measuring capital or other fixed factors explicitly, using the procedure developed by Houthakker in the 1950s. Houthakker's method is based on the probability distribution of the productivity of the variable factor. Fitting different distributions to cross-sectional data on U.S. productivity, it is shown that if the elasticity of substitution between human and robotic labor is greater than about 1.9, the burgeoning of AI technologies will cause a decline in aggregate wages, other things equal. For the manufacturing sector, an even smaller human-robot elasticity of substitution is likely to result in declining wages of industrial workers as robots proliferate.     

中国"超额货币"成因的进一步检验

中国的超额货币一直是理论界颇有争议的话题,因而关于超额货币成因的理论假说有很多种。基于对以往的理论假说进行总结与质疑的基础上,利用货币需求的收入弹性与价格弹性对交易方程式进行调整,并利用中国1991-2003年的数据对调整后的模型进行检验,结果发现:货币需求的收入弹性与价格弹性的变化是导致中国超额货币存在的主要原因。     

MEASURING PRICE ELASTICITY OF SECTORIAL IMPORTS

Previous published studies have estimated the long‐run cointegrating relationship to infer the price elasticity of imports, but a stable long‐run cointegrating relationship might not be detected in the data, especially in the case of sectoral data. This paper develops a method to estimate the price elasticity of imports based on a vector autoregression model, which can be applied when a stable long‐run cointegration relationship does not exist. The methods developed in past studies and our method are applied to Korean sectoral imports data to illustrate the usefulness of our method.     

Structural Changes in Australian Manufacturing Industry*

The paper uses a neoclassical production function and historical data to test for structural stability in Australian manufacturing industry. The production function is an extended constant elasticity of substitution form in which factor substitution elasticity, returns to scale and market structure in output, capital and labour are testable hypotheses. Tests for structural changes in homogeneity and factor substitution elasticity relations are based on overall and individual tests of covariance analysis and also on a special version of the Swerling-Kalman filtering systems as proposed by Cooley and Prescott. The empirical findings possess desirable statistical properties and indicate the existence of structural instability in the industry. The evidence also repudiates the assumptions of unitary factor substitution elasticity, constant returns to scale and market competitiveness in output and factors of production.