Visual exploration of high dimensional scalar functions

An important goal of scientific data analysis is to understand the behavior of a system or process based on a sample of the system. In many instances it is possible to observe both input parameters and system outputs, and characterize the system as a high-dimensional function. Such data sets arise, for instance, in large numerical simulations, as energy landscapes in optimization problems, or in the analysis of image data relating to biological or medical parameters. This paper proposes an approach to analyze and visualizing such data sets. The proposed method combines topological and geometric techniques to provide interactive visualizations of discretely sampled high-dimensional scalar fields. The method relies on a segmentation of the parameter space using an approximate Morse-Smale complex on the cloud of point samples. For each crystal of the Morse-Smale complex, a regression of the system parameters with respect to the output yields a curve in the parameter space. The result is a simplified geometric representation of the Morse-Smale complex in the high dimensional input domain. Finally, the geometric representation is embedded in 2D, using dimension reduction, to provide a visualization platform. The geometric properties of the regression curves enable the visualization of additional information about each crystal such as local and global shape, width, length, and sampling densities. The method is illustrated on several synthetic examples of two dimensional functions. Two use cases, using data sets from the UCI machine learning repository, demonstrate the utility of the proposed approach on real data. Finally, in collaboration with domain experts the proposed method is applied to two scientific challenges. The analysis of parameters of climate simulations and their relationship to predicted global energy flux and the concentrations of chemical species in a combustion simulation and their integration with temperature.     

Cooperative exploration of distributed worlds in WAVE

This paper modifies the WAVE model for parallel processing in virtual networks to explore and process continuous physical worlds. Expressing distributed activity by cooperative jobs spreading in space and “seeing” each other, rather than as vehicles exchanging messages, the model allows complex missions to be planned in a very flexible manner, with mobile hardware being assigned to the evolving space-conquering programs (waves) dynamically, when required or available. A number of cooperative scenarios in a physical world demonstrate the simplicity and compactness of the wave code. The execution of waves by mobile hardware is discussed, including run-time mapping of waves to vehicles, and supporting multiple distributed jobs in cases of hardware shortages. WAVE can be used efficiently for solving complex problems in space by organized groups of cheap specialized mobile robots, where intelligent behavior is provided by very high level of system organization rather than by the smartness of individual units. In a broader sense, it may also serve as a basic technology for parallel and distributed simulation, and the management of evolution and self-organization of large open systems of different natures.     

Rare category exploration

Rare category discovery aims at identifying unlabeled data examples of rare categories in a given data set. The existing approaches to rare category discovery often need a certain number of labeled data examples as the training set, which are usually difficult and expensive to acquire in practice. To save the cost however, if these methods only use a small training set, their accuracy may not be satisfactory for real applications. In this paper, for the first time, we propose the concept of rare category exploration, aiming to discover all data examples of a rare category from a seed (which is a labeled data example of this rare category) instead of from a training set. To this end, we present an approach known as the FRANK algorithm which transforms rare category exploration to local community detection from a seed in a kNN (k-nearest neighbors) graph with an automatically selected k value. Extensive experimental results on real data sets verify the effectiveness and efficiency of our FRANK algorithm.     

Curvature behaviours at extraordinary points of subdivision surfaces

During the development of subdivision surface methods one of the important questions has been the degree of continuity of the limit surface. In particular whether continuity of curvature can be achieved at the extraordinary points. However, there are several different curvature behaviours, not just two, and this note demonstrates them by examples.     

MIS中的协同开发设计

该文提出了ＭＩＳ中协同开发设计的思想。以Ｏｒａｃｌｅ为例，说尽地描述和比较两种协同开发的实现方法。该思想的应用可大大增强和完善ＭＩＳ的功能。     

Generalized shape operators on polyhedral surfaces

This work concerns the approximation of the shape operator of smooth surfaces in R³ from polyhedral surfaces. We introduce two generalized shape operators that are vector-valued linear functionals on a Sobolev space of vector fields and can be rigorously defined on smooth and on polyhedral surfaces. We consider polyhedral surfaces that approximate smooth surfaces and prove two types of approximation estimates: one concerning the approximation of the generalized shape operators in the operator norm and one concerning the pointwise approximation of the (classic) shape operator, including mean and Gaussian curvature, principal curvatures, and principal curvature directions. The estimates are confirmed by numerical experiments.     

Cooperative estimation of human motion and surfaces using multiview videos

We propose a human motion tracking method that not only captures the motion of the skeleton model but also generates a sequence of surfaces using images acquired by multiple synchronized cameras. Our method extracts articulated postures with 42 degrees of freedom through a sequence of visual hulls. We seek a globally optimized solution for likelihood using local memorization of the “fitness” of each body segment. Our method efficiently avoids problems of local minima by using a mean combination and an articulated combination of particles selected according to the weights of the different body segments. The surface is produced by deforming the template and the details are recovered by fitting the deformed surface to 2D silhouette rims. The extracted posture and estimated surface are cooperatively refined by registering the corresponding body segments. In our experiments, the mean error between the samples of the deformed reference model and the target is about 2 cm and the mean matching difference between the images projected by the estimated surfaces and the original images is about 6%.     

开放协作环境中协作信息本体模型的研究

CSCW的发展提出了构建开放协作环境的需求，纲格技术为这一开放协作环境的研究带来了新机遇。在这一环境中，需综合研究一系列相关关键技术，包括协作虚拟场地技术、协作感知技术、协同服务总线技术和协同信息共享空间等，并要将这些技术同已有CSCW中的研究成果相融合，包括如工作流技术、各种交互群件技术。本文介绍这一开放协作环境的基本架构，并重点阐述协同信息共享空间研究中协作信息本体模型的研究。     

多媒体协同编辑中共享粒度的研究与实现

首先阐述了协同编辑和共享粒度(Sharing Granularity)的概念,以及两者之间的关系.并通过作者参与设计的一个协同编辑的实验系统(Swan Editor)具体阐述了共享粒度的设计思想及实现方式.最后进一步讨论了共享粒度的意义以及与协同工作系统中其他研究内容的关系.     

Improvement of free-form surfaces for product styling applications

There are a number of ways of describing free-form surfaces within geometric modelling systems. For product styling and related activities, there is a need to ensure that surface quality is good and that patches join together smoothly. Additional parameters can be introduced to allow surfaces to be modified. This raises the question of whether these can be chosen automatically, and this in turn requires measures of what is a ‘fair’ surface. Measures based on surface curvature are discussed and applied to adjust surface patches presented in terms of point meshes.     

Direct volume rendering of multiple scalar fields

Rendering of volume data without forming geometric objects is often termed direct volume rendering. Most of the previously developed methods for this purpose are restricted to display of one scalar variable. This paper presents methods for direct volume rendering of several scalar variables defined at discrete points in three-dimensional space. Typical requirements for the rendering of such data are proposed and then used as a basis for the derivation of a computational model. The proposed model uses a classification technique to composite specific types of information from different scalar fields. The visual display of the composite information is controlled through a set of rendering parameters.     

Stabilization of symmetric formations to motion around convex loops

We provide a cooperative control algorithm to stabilize symmetric formations to motion around closed curves suitable for mobile sensor networks. This work extends previous results for stabilization of symmetric circular formations. We study a planar particle model with decentralized steering control subject to limited communication. Because of their unique spectral properties, the Laplacian matrices of circulant graphs play a key role. We illustrate the result for a skewed superellipse, which is a type of curve that includes circles, ellipses, and rounded parallelograms.     

小组合作学习在《非线性编辑》课程中的应用

本文从从实际教学工作出发,阐述了小组合作学习在《非线性编辑》课程教学的具体应用,提高了教学效果,促进了学生素质的全面发展。     

Accurate adaptive level set method and sharpening technique for three dimensional deforming interfaces

In this paper, we demonstrate improved accuracy of the level set method for resolving deforming interfaces by proposing two key elements: (1) accurate level set solutions on adapted Cartesian grids by judiciously choosing interpolation polynomials in regions of different grid levels and (2) enhanced re-initialization by an interface sharpening procedure. The level set equation is solved using a fifth order WENO scheme or a second order central differencing scheme depending on availability of uniform stencils at each grid point. Grid adaptation criteria are determined so that the Hamiltonian functions at nodes adjacent to interfaces are always calculated by the fifth order WENO scheme. This selective usage between the fifth order WENO and second order central differencing schemes is confirmed to give more accurate results compared to those in literature for standard test problems. In order to further improve accuracy especially near thin filaments, we suggest an artificial sharpening method, which is in a similar form with the conventional re-initialization method but utilizes sign of curvature instead of sign of the level set function. Consequently, volume loss due to numerical dissipation on thin filaments is remarkably reduced for the test problems.     

Cooperative behavior of interacting robots

We have researched the efficiency of cooperative behavior of interacting multirobots. In this paper, we generalize the definition of swarm intelligence and examine the emergence of the generalized swarm intelligence (here we call it “swarm function”) through the task of gathering pucks in a field by interacting simple robots. This robot has a drive system and the simplest means of interaction. The effectiveness of group behavior was studied for various (homogeneous, localized) puck distributions. To evaluate the efficiency of group behavior, we proposed a scaling relation between the task completion time and the number of robots, and examined the relation between the interaction duration and the efficiency of the group. We also proposed a simplified state transition diagram of the group and analysed their characteristics using it. This work was presented, in part, at the Second International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1997.     

基于大纲的网上协同编辑环境的实现

介绍了CSCW的基本概念，论述了一个协同编辑系统的设计方法，该系统采用工作流的管理机制，设置了4个角色，由主编负责建立整个作品的大纲和任务的分配，由各个编辑在网上共同完成各自子作品的创作，审稿人负责各个子作品的审核，子作品都审核通过后，由主编完成整个作品的生成和发布。     

Cooperative Visualization of Computational Fluid Dynamics

Tempus Fugit/Interview is a computational fluid dynamics visualization application for which processing is distributed between high performance graphics workstations and supercomputers. Facilities are provided in the application for more than one user to view shared images creating a cooperative visualization environment. The way in which the computation is partitioned between the super computer and the workstations is critical to the capability of the application to present simultaneous, identical, animated images of fluid dynamics to more than one user.     

UUV群探测系统仿真设计

研究水下航行器(UUV)群协同探测问题,系统用多传感器协同探测,执行警戒、侦察、监视水下航行等作战任务,要求实时快速和准确探测。针对目前水下情况复杂,UUV导航精度低、水声通信误码率大等状态。为解决算法研制与实际结合不紧密的问题,提高UUV群协同探测系统性能,采用GUI函数接口,设计并实现了UUV群协同探测仿真系统。系统可通过可视化界面,用MATLAB平台对UUV群用于多目标的协同探测算法进行仿真。仿真结果表明,仿真系统能够满足UUV协同仿真测试要求,对于UUV群协同探测系统的研制具有重要的应用价值。     

移动Agent在协同电子商务系统中的分布式应用设计

如何实现高效的、动态的资源共享和开放式协作，并有效地解决其集成性、智能性和开放性的不足将是协同电子商务的核心问题。移动Agent为解决这一些问题提供了一种新的方案，为此本文设计一种分布式的基础应用模型，并给出一个应用的案例。