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.     

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.     

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.     

Remote data analysis,visualization and problem solving environment (PSE) based on wavelets in the geosciences

We discuss here the issues faced by earth scientists in analyzing and visualizing large datasets over a GRID-like setup from a client-server perspective. We approach this problem by using a remote, web-based visualization and data analysis framework, called WEB-IS, and by employing second-generation wavelets as a means for reducing the amount of data transferred and for extracting coherent features in complex geophysical flows and surface faulting patterns. As an example, we describe how onboard processors on satellites can function as a server for beaming down extracted information to the client computer on the ground, thus exemplifying WEB-IS as a viable middleware on a GRID network for geosciences.     

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.     

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.     

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.     

How private is private information? The ability to spot deception in an economic game

We provide experimental evidence on the ability to detect deceit in a buyer–seller game with asymmetric information. Sellers have private information about the value of a good and sometimes have incentives to mislead buyers. We examine if buyers can spot deception in face-to-face encounters. We vary whether buyers can interrogate the seller and the contextual richness. The buyers’ prediction accuracy is above chance, and is substantial for confident buyers. There is no evidence that the option to interrogate is important and only weak support that contextual richness matters. These results show that the information asymmetry is partly eliminated by people’s ability to spot deception.     

移动社会化媒体技术接受与匹配影响因素研究——以移动微博客户端发布行为为例

移动微博是移动社会化媒体技术的典型代表,其技术与用户需求高度匹配,用户粘性日益提高,正逐渐改变着人们的联系方式,基于需求技术匹配理论和动机理论的整合拓展模型对用户使用移动终端发布微博的行为进行研究,用户需求特征和任务特征均对需求任务匹配有正向影响,最终对行为意愿产生影响。以感知有用性为代表的外部动机和以感知愉悦性为代表的内部动机对行为意愿也存在正向影响。对移动微博客户端提供商提升服务水平提供了新的思路。     

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.     

Do data policy restrictions impact the productivity performance of firms and industries?

This paper examines how policies regulating the cross‐border movement and domestic use of electronic data on the internet impact the productivity of firms in sectors relying on electronic data. In doing so, we collect regulatory information on a group of developed economies and create an index that measures the regulatory restrictiveness of each country's data policies. The index is based on observable policy measures that explicitly inhibit the cross‐border movement and domestic use of data. Using cross‐country firm‐level and industry‐level data, we analyse econometrically the extent to which these data regulations over time impact the productivity performance of downstream firms and industries, respectively. We show that stricter data policies have a negative and significant impact on the performance of downstream firms in sectors reliant on electronic data. This adverse effect is stronger for countries with strong technology networks, for servicified firms, and holds for several robustness checks.     

Barriers to investment in ICT

This paper studies the complementarity between investment in information and communication technologies (ICT) and the related investment in human and organizational capital. Using firm-level data taken from a large sample of Italian manufacturing firms, an ICT marginal product much higher than its user cost is estimated. It is then argued that missing complementary investments may have acted as barriers to investment in ICT. Results support the conjecture that the marginal product excess over the user cost is due to those firms that did not complement their ICT investment with an increase in the human capital of their labour force and with a reorganization of the workplace.     

农业资源高效利用决策支持系统的属性信息与属性数据管理--以宁津县为例

本文以宁津县为例,研制了农业资源高效利用决策支持信息系统的一部分－属性信息与属性数据管理信息系统,提出了系统结构设计与数据库设计,对用户需求进行了扼要分析,并论述了系统的特点。这一新技术可以为地方建立农业资源高效利用决策支持系统服务。     

Geographic patterns of trading profitability in Xetra

Transaction data from the electronic trading system Xetra of the German Security Exchange is used to explore the relationship between trader location and trading profitability. The non-discriminatory nature of the electronic trading system and its wide international adoption allows interesting conclusions about the information geography of international equity trading. We use spectral analysis to examine trading profitability over intraday, intraweek, and intraquarter inventory cycles. Proprietary trader accounts reveal the underperformance of foreign traders at all three trading horizons. Our analysis confirms the hypothesis of financial market segmentation due to international information barriers.     

To disclose or not? An analysis of software user behavior

We address the ongoing debates over disclosing information about software vulnerabilities through an open public forum. A game-theoretic approach is used to show that full public disclosure can be an equilibrium strategy in a game played by rational loss-minimizing agents. We provide conditions under which full disclosure of vulnerabilities improves social welfare and analyze the effect of vendor and product characteristics, as well as the composition of the pool of software users on the decisions to disclose. We also provide conditions under which user threats to vendors to disclose after a grace period or users’ ability to develop fixes themselves further improve welfare. The likelihood that user-developed fixes improve welfare increases with user familiarity with the details of software, providing an argument for “open source” software.     

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.     

Designing incentives for online question-and-answer forums

We provide a game-theoretic model of sequential information aggregation motivated by online question-and-answer forums. An asker posts a question and each user decides when to aggregate a unique piece of information with existing information. When the quality exceeds a certain threshold, the asker closes the question and allocates points to users. We consider the effect of different rules for allocating points on the equilibrium behavior. A best-answer rule provides a unique, efficient equilibrium in which all users respond in the first round, for substitutes valuations over information. However, the best-answer rule isolates the least efficient equilibrium for complements valuations. We demonstrate alternate scoring rules that provide an efficient equilibrium for distinct subclasses of complements valuations, and retain an efficient equilibrium for substitutes valuations. We introduce a reasonable set of axioms, and establish that no rule satisfying these axioms can achieve the efficient outcome in a unique equilibrium for all valuations.     

PREFERENCES UNDER IGNORANCE

A decision maker (DM) makes choices from different sets of alternatives. The DM is initially ignorant of the payoff associated with each alternative and learns these payoffs only after a large number of choices have been made. We show that, in the presence of an outside option, once payoffs are learned, the optimal choice rule from sets of alternatives can be rationalized by a DM with strict preferences over all alternatives. Under this model, the DM has preferences for preferences while being ignorant of what preferences are “right.”     

电子信息产业国内价值链省域比较优势测度及空间差异研究

为应对后疫情时代全球电子信息产业加剧的“比较优势陷阱”,中国亟需通过国内价值链省域比较优势的互补协同提升整体国际竞争力。在价值链产品内,基于垂直专业化分工框架,兼顾增值能力与劳动生产率两个维度,使用非竞争型投入占用产出模型,设计一个评测国家内部区域电子信息产业真实比较优势的新指标。结果表明,东部沿海省域比较优势强度与广度最为显著,内陆省域比较优势集中于上游能源型部门;制造业部门比较优势凸显,服务业部门比较优势相对薄弱;比较优势高省域集中度与低省域集中度的产业部门中,均存在整体比较优势强弱差异,其中,高省域集中度产业部门比较优势强度更高。