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.     

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.     

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.     

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.     

gLucifer: next generation visualization framework for high-performance computational geodynamics

High-performance computing provides unprecedented capabilities to produce higher resolution 4-D models in a fraction of time. Thus, the need exists for a new generation of visualization systems able to maintain parity with the enormous volume of data generated. In attempting to write this much data to disk, each computational step introduces a significant performance bottleneck, yet most existing visualization software packages inherently rely on reading data in from a dump file. Available packages make this assumption of postprocessing at quite a fundamental level and are not very well suited for plotting very large numbers of specialized particles. This necessitates the creation of a new visualization system that meets the needs of large-scale geodynamic modeling. We have developed such a system, gLucifer, using a software framework approach that allows efficient reuse of our efforts in other areas of research. gLucifer is capable of producing movies of a 4-D data set “on the fly” (simultaneously with running the parallel scientific application) without creating a performance bottleneck. By eliminating most of the human efforts involved in visualizing results through postprocessing, gLucifer reconnects the scientist to the numerical experiment as it unfolds. Data sets that were previously very difficult to even manage may be efficiently explored and interrogated without writing to disk, and because this approach is based entirely on memory distributed across as many processors as are being utilized by the scientific application, the visualization solution is scalable into terabytes of data being rendered in real time.     

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.     

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.     

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.     

Developing and Implementing an Internet-Based Financial System Simulation Game

Thanks to the Internet and server-side technology such as Active Server Pages (ASP), faculty can develop, implement, and share interactive pedagogy easily and inexpensively. The Financial System Simulator (FSS) is an example of an interactive game that the author has developed. The FSS is an Internet-based, interactive teaching aid that introduces undergraduate students to the domestic and international consequences of monetary policy. Although simulators are common among computer-aided interactive learning devices in today's undergraduate economics curricula, the FSS is different from the others because it allows students, who represent nations, to interact with each other rather than with a computer. The exercise provides users with real-time outcomes based on their decisions, as well as the decisions of other students. According to student surveys, the game helped students understand monetary policy and kept students motivated and interested.     

从统计学的视角看我国人口大规模流动

笔者通过对中国大规模人口流动形成机理的分析,认为经济社会制度的变迁引发了我国大规模人口流动,而地区间、城乡间已经存在多年的经济差势和收入差距如果不能得到根本性扭转,人口大规模流动的状况便会长期存在下去。     

Optimal Reserves and Short‐Term Interest Rates in a Model of Bank Runs

A global game framework of bank runs is used to analyse a bank's choice of its reserve level and short‐term interest rate. Higher level of reserves and a lower short‐term interest rate would decrease the probability of bank runs. When the bank's reserve policy is transparent, it will hold excess reserves to discourage withdrawals by patient depositors. This inefficiency of excess reserves increases with the proportion of impatient depositors. When the bank has private information about its reserve level, it will follow a more risky strategy of choosing lower reserves and higher early return than what maximizes depositor welfare and increases the probability of bank runs.     

有线电视台的技术支撑与管理体制——以江苏有线电视台为例

江苏有线电视台成立于1994年4月,章剑华任台长。1994年12月28日,江苏有线电视台正式播出,1998年8月8日开播大型互动式综艺电视节目《非常周末》,最高收视率42.38%,该节目一直办到2010年5月,是江苏电视史上收视率最高的综艺节目。2000年,江苏有线电视台广告创收1.8亿元,江苏市场占有率55%,利润近亿元,进入全国省级有线媒体前三强。2001年6月,江苏有线台并入江苏省广播电视总台,章剑华任总台台长。江苏有线电视台的台训、台歌与台标体现新媒体时代的精神,其组织体系、频道结构、节目样式、基本建设、经营创收、技术实施、网络建设顺应潮流,技术支撑、品牌特色、机制创新、管理体制领先行业,业绩显著,成为中国广播电视行业的标杆之一。     

有线电视台的经营创收策略——以江苏有线电视台为例

江苏有线电视台筹建之初(1994年4月～2001年6月)开办经费仅30万元,一度靠筹措的800万元维持运转.江苏有线台依托文体频道、影剧频道及《东方文化周刊》经营创收,其经营创收策略在于制造品牌、维系品牌和发展品牌,以此为指导思想,创办《非常周末》、《地球村》等品牌栏目.重视大型活动和受众工作,尝试广告代理和商业运作,将其纳入经营创收的统一规划,以扩大品牌的知名度、影响力和美誉度,变小作坊式的分散经营为有集约、规模效应的社会化大合作.1995年还清借贷,1996年创收2000万,1997年创收3000多万,1998年创收6000多万,1999年创收8000万.2000年创收1.8亿元,江苏市场占有率55％,位居全国省级有线媒体前三名,与江苏电视台旗鼓相当.     

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.     

A visualization system for mineral elasticity

The authors have developed an efficient visualization system to gain insight into large collections of mineral elasticity data produced by an increasing number of both theoretical calculations and experiments. The system allows us to visualize multivariate elastic moduli (i.e., elastic constant tensors) and their variation with composition, pressure and temperature. Moreover, it supports visualization of elastic wave propagation in an anisotropic medium by rendering the wave velocity data, which are calculated as a function of propagation direction in a three-dimensional space. This paper describes the design, implementation and application of the visualization scheme we have developed for mineral elasticity. In particular, our scheme exploits a combination of parallel coordinates, star plot, scatter plot and polygon-surface rendering techniques, which are implemented using OpenGL, GLUI and C++. The result is a highly portable and flexible interactive visualization system. For illustration, the elastic properties of several important oxide and silicate minerals are successfully visualized as a function of pressure and temperature.     

Can debt crises be self-fulfilling?

Several papers argue that debt crises can be the result of self-fulfilling expectations that no one will lend to a country, triggering default and rationalizing the refusal to lend. I show these coordination failures can be eliminated by a combination of state-contingent securities and a mechanism that allows investors to promise to lend only if enough other investors do so as well. This suggests that runs on the debt of a single borrower (such as the government) can be eliminated and that self-fulfilling features are more plausible when externalities among many decentralized borrowers allow for economy-wide debt runs to occur.     

影响西藏地区GDP增长的相关要素分析——基于经济权利禀赋视角

实施西部大开发战略十年来,在西藏自治区党委、政府的正确领导下,西藏的经济社会发展取得了有目共睹的巨大成就.毋庸置疑的是,相对落后的西藏在未来的发展中仍然会面临很多棘手的难题.弄清影响西藏地区GDP增长的相关因素,将会对西藏的发展有极好的促进作用.本研究基于经济权利禀赋的视角,运用SPSS软件处理数据,建立多元非线性回归分析模型,得出影响因素与GDP之间的函数关系.     

BANK RUNS: DEPOSIT INSURANCE AND CAPITAL REQUIREMENTS*

Diamond and Dybvig provide a model of intermediation in which deposit insurance can avoid socially undesirable bank runs. We extend the Diamond–Dybvig model to evaluate the costs and benefits of deposit insurance in the presence of moral hazard by banks and monitoring by depositors. We find that complete deposit insurance alone will not support the first‐best outcome: depositors will not have adequate incentives for monitoring and banks will invest in excessively risky projects. However, an additional capital requirement for banks can restore the first‐best allocation.     

中国跨国公司与对外投资地区互动机制研究

跨国公司在对外投资过程中与投资地区的互动是双方反复博弈的结果，建立良好的互动机制是一种双赢策略。互动机制的建立将有助于对外投资企业提高技术学习和竞争能力，适应投资地的市场与文化，规避对外投资中存在的风险，为中国跨国公司创造有利的外部发展条件。外部因素通过良好的互动机制也可以与内部因素产生相互推动作用。     

石墨烯技术及产业发展现状

石墨烯(graphene)是一种新型的碳基材料,具有极好的结晶性及电学性能,在能源、半导体、生物医学等多个领域具有良好的应用前景,已成为发达国家必争的战略制高点。美国在全球率先将石墨烯研究上升为国家发展战略,欧盟投入巨资资助开发石墨烯在能源和数字技术等领域的应用,英国拟投资6 100万英镑建立国家石墨烯研究所,日本、韩国也持续开展了一系列与石墨烯相关的研究和应用。我国对石墨烯材料的基础研究处于国际领先地位,但在器件制造和应用方面仍很欠缺。我国应加强石墨烯规模化制备技术和改性技术的研究,加强石墨烯的应用研究,并在石墨烯研究方面加强产学研联合研究和国际合作。