Interactive space deformation with hardware-assisted rendering

The authors introduce a new approach for the deformation of surface and raster models in two and three dimensions. Rather than deforming the model, they deform the agents employed to render it. The method uses one deformation tool (the deflector) to deform any object that is ray traceable. Based on deforming the rendering primitives rather than objects, the approach invests computation effort only in those regions of the model that contribute to the final image     

Interactive visualization of Earth and space science computations

Scientists often view computer algorithms as risk-filled black boxes. The barrier between scientists and their computations can be bridged by techniques that make the internal workings of algorithms visible and that allow scientists to experiment with their computations. We describe two interactive systems developed at the University of Wisconsin-Madison Space Science and Engineering Center (SSEC) that provide these capabilities to Earth and space scientists. These visualization packages help scientists see the internal workings of their algorithms and thus understand their computations     

Interactive ads recommendation with contextual search on product topic space

The rapid popularization of various online media services have attracted large amounts of consumers and shown us a large potential market of video advertising. In this paper, we propose interactive service recommendation based on ad concept hierarchy and contextual search. Instead of traditional ODP (Open Directory Project) based approach, we built a ad domain based concept hierarchy to make the most of the product details over the e-commerce sites. Firstly, we capture the summarization images related to the advertising product in the video content and search visually similar product images from the built product image database. Then, we aggregate the visual tags and textual tags with K-line clustering. Finally, we map them to the product concept space and make keywords suggestion, and users can interactively select keyframes or keywords to personalize their intentions by textual re-search. Experiments and comparison show that the system can accurately provide effective advertising suggestions.     

Interactive balance space approach for solving multi-level multi-objective programming problems

This paper studies a multi-level multi-objective decision-making (ML-MODM) problems with linear or non-linear constraints. The objective functions at each level are non-linear functions, which are to be maximized or minimized.This paper presents a three-level multi-objective decision-making (TL-MODM) model and an interactive algorithm for solving such a model. The algorithm simplifies three-level multi-objective decision-making problems by transforming them into separate multi-objective decision making problems at each level, thereby avoiding the difficulty associated with non-convex mathematical programming. Our algorithm is an extension of the work of Shi and Xia [X. Shi, H. Xia, Interactive bi-level multi-objective decision making, Journal of the Operational Research Society 48 (1997) 943-949], which dealt with interactive bi-level multi-objective decision-making problems, with some modifications in assigning satisfactoriness to each objective function in all the levels of the TL-MODM problem. Also, we solve each separate multi-objective decision making problem of the TL-MODM problem by the balance space approach.A new formula is introduced to interconnect the satisfactoriness and the proportions of deviation needed to reflect the relative importance of each objective function. Thus, we have the proportions of deviation including satisfactoriness.In addition, we present new definitions for the satisfactoriness and the preferred solution in view of singular-level multi-objective decision making problems that corresponds to the η-optimal solution of the balance space approach. Also, new definitions for the feasible solution and the preferred solution (η-optimal point) of the TL-MODM problem are presented. An illustrative numerical example is given to demonstrate the algorithm.     

基于自学习采样粒子滤波器的不完备故障空间交互诊断方法

针对不完备空间混合系统,提出一种基于自学习采样粒子滤波器(SLSPF)的交互诊断方法.融入自学习采样机制,利用自学习即时概率指导采样,以摆脱粒子滤波器对转移概率的依赖;结合自学习采样与诊断的动态交互方式调整模式空间,使粒子滤波器采样粒子数动态减少;同时给出了不完备信息空间的真实模式与未知模式阈值的决策条件.实验结果表明,尤其在高维状态空间下,SLSPF不仅可以保证粒子滤波器的诊断精度,而且能够提高计算效率.     

Interactive parameter space design for robust performance of MISO control systems

This paper presents a method for the design of nonconservative low-order controllers achieving robust performance in the case of multi-input single-output parallel structure plants subject to unstructured uncertainty. The first step is the analytical generation of gain-phase controller bounds, as in quantitative feedback theory (QFT). Then, to avoid the difficult step of QFT loop shaping, which often produces high-order controllers, these bounds are translated into the controller parameter space where the iterative design of low fixed order controllers takes place. This, as well as the design transparency offered by this technique, constitutes appreciable advantages over the other popular robust performance design method of /spl mu/-synthesis. Other important features are the fact that no extra conservatism is introduced by the method presented and the fact that the method is directly compatible with a sequential loop closing strategy. Finally, the direct search optimization of any additional secondary criteria is possible.     

自适应分区多代理模型交互式遗传算法

为提高交互式遗传算法的性能.提出一种自适应分区多代理模型交互式遗传算法.该算法基于关键维分割进化初期的搜索空间,同时基于进化进程、逼近精度以及用户评价敏感度,自适应地分割进化中后期的搜索空间.在子空间上,采用多类代理模型学习用户对进化个体评价,并用于评价后续进化的部分或全部个体.将该算法应用于服装进化设计系统,实验结果表明,算法在种群多样性、减轻用户疲劳及用户对优化结果满意度等方面均具有优越性.     

Interactive control system design by a mixedH∞-parameter space method

This paper presents an interactive graphical method to determine sets of stabilizing controllers satisfying any combination of constraints on the sensitivity, complementary sensitivity, and input sensitivity transfer functions. The method is limited to single-input/single-output systems but offers significant advantages over current H^∞ methods. It can handle pure time delays in an exact manner. The weighting functions need not be rational. By virtue of producing the required parameter space region for the frequency response criteria, subsequent direct time-domain optimization is possible. The controllers obtained are of lower order for comparable performance than those produced by current H^∞ techniques. The method is particularly well suited to robust control problems, where frequency domain constraints emerge from the analysis of uncertainties in the system, and also to suboptimal problems, where the frequency-domain loop shaping is used to achieve time-domain specifications     

Interactive machinability analysis of free-form surfaces using multiple-view image space techniques on the GPU

In this paper we present a set of graphics hardware accelerated algorithms to interactively evaluate the machinability of complex free-form surfaces. These algorithms work in image space and easily interface with all common formats available on CAD systems. The running time of these algorithms is independent of the complexity of the surface to be analyzed and depends only on the size of the projected image of the surface and the largest available tool head. Interactive speed is achieved through clever use of data-parallel techniques that map nicely onto the programming model of modern programmable graphics processing units. We demonstrate a method for pre-calculating and storing the machinability of a surface within a texture to further reduce rendering costs. The algorithms are implemented and tested on a complex set of parts and their performance has been analyzed.     

Finite element MAC scheme in general curvilinear coordinates

A combined study of F.D. and F.E. methods for 2-D incompressible Navier-Stokes flows is undertaken. In primitive variable formulation, major difficulties are connected to spurious numerical oscillations which may arise from the enforcement of the incompressibility constraint. With regard to this problem, various F.D. schemes differ essentially according to the variable location on the mesh points, while F.E. schemes are analogously differentiated by the interpolation functions adopted for the different variables. In the present paper, we propose an F.E. analog of MAC scheme, which can be accomplished by different interpolation functions for the two velocity components. This new F.E. scheme-although based on low order approximations-eliminates all spurious oscillations. The extension to curvilinear quadrilateral elements—which is needed in order to achieve geometrical versatility—requires the problem to be formulated in general curvilinear coordinates and the contravariant velocity components to be assumed as variables. Some numerical results are presented and discussed, in order to assess the capabilities of the proposed model.     

Hierarchical models of elastic shells in curvilinear coordinates

In the present paper, static and dynamical problems for linearly elastic shells in curvilinear coordinates are considered. Hierarchies of two-dimensional models for corresponding boundary and initial boundary value problems are constructed within the variational settings. The existence and uniqueness of solutions of the reduced problems are investigated in suitable spaces. Under the conditions of solvability of the original static or dynamical problem, convergence of the sequence of vector functions of three variables restored from the solutions of the constructed two-dimensional problems to the solution of the three-dimensional problem is proved and approximation error is estimated.     

Sharing,finding and reusing end-user code for reformatting and validating data

To help users with automatically reformatting and validating spreadsheets and other datasets, prior work introduced a user-extensible data model called “topes” and a supporting visual programming language. However, no support has existed to date for users to exchange and reuse topes. This functional gap results in wasteful duplication of work as users implement topes that other people have already created.In this paper, a design for a new repository system is presented that supports sharing and finding of topes for reuse. This repository tightly integrates traditional keyword-based search with two additional search methods whose usefulness in repositories of end-user code has gone unexplored to date. The first method is “search-by-match”, where a user specifies examples of data, and the repository retrieves topes that can reformat and validate that data. The second method is collaborative filtering, which has played a vital role in repositories of non-code artifacts.The repository’s search functionality was empirically tested on a prototype repository implementation by simulating queries generated from real user spreadsheets. This experiment reveals that search-by-match and collaborative filtering greatly improve the accuracy of search over the traditional keyword-based approach, to a recall as high as 95%. These results show that search-by-match and collaborative filtering are useful approaches for helping users to publish, find, and reuse visual programs similar to topes.     

An unbiased detector of curvilinear structures

The extraction of curvilinear structures is an important low-level operation in computer vision that has many applications. Most existing operators use a simple model for the line that is to be extracted, i.e., they do not take into account the surroundings of a line. This leads to the undesired consequence that the line will be extracted in the wrong position whenever a line with different lateral contrast is extracted. In contrast, the algorithm proposed in this paper uses an explicit model for lines and their surroundings. By analyzing the scale-space behavior of a model line profile, it is shown how the bias that is induced by asymmetrical lines can be removed. Furthermore, the algorithm not only returns the precise subpixel line position, but also the width of the line for each line point, also with subpixel accuracy     

Grid orthogonalization for curvilinear alternating-direction techniques

A method is developed for an a posteriori iterative improvement to an arbitrary computational grid. Local corrections to the coordinates of the grid points are used to form a global cost function which is minimized with respect to a single parameter. The local corrections and cost function can be constructed to maximize the local smoothness and/or the local orthogonality of the grid. The advantage of this method is that it allows the user to generate an initial grid using any inexpensive method, and then the grid can be improved with respect to both orthogonality and smoothness.This technique was used to generate grids for a finite element alternating-direction method which uses curved elements. A sample transient diffusion problem was solved on a series of grids to investigate the sensitivity of the curvilinear alternating-direction method to grid orthogonalization. The initial grid was highly nonorthogonal and each grid produced by the automatic grid generation program was smoother and more orthogonal.This work shows that the adaptive grid program can be easily used to generate nearly orthogonal grids and it shows that the curvilinear alternating-direction technique is not highly sensitive to nonorthogonality of the grid. It is shown that as long as a grid is somewhat reasonable, the alternating-direction method will perform quite well.     

Inpainting images with curvilinear structures propagation

Inpainting images with smooth curvilinear structures interrupted is a challenging problem, because the structures are salient features sensitive to the human vision system and they are not easy to be completed in a visually pleasing way, especially when gaps are large. In this paper, we propose an approach to address this problem. A curve with a desired nice shape is first created to smoothly extend the missing structure from the known to unknown regions. As the curve partitions the unknown region into separate areas, textures can be filled independently into each area. We then adopt a patch-based texture inpainting method enhanced by a novel similarity measurement of patches. After that, very abrupt edges caused by different inpainted colours on their two sides need to be smoothed for natural colour transition across the curve. Experimental results demonstrate the effectiveness of the proposed approach.     

The effect of asymmetry on micromixing in curvilinear microchannels

The necessity of microscale mixing processes has been tremendously increasing in most of the microsize chemical and biochemical devices during recent years, particularly in the design of lab-on-a-chip and micrototal analysis systems. Different approaches were implemented in the available micromixers in the literature for improving the mixing performance. Due to the absence of any external source, mixing by utilizing passive mixing techniques is more economical. In curvilinear microchannels, which offer effective passive mixing, chaotic advection results in continuous radial perforation of inter-diffusion layer between the fluid streams due to the transverse secondary flows. In this study, the effects of Dean vortices and secondary flows were investigated in asymmetrical polydimethylsiloxane curvilinear rectangular microchannels, which were fabricated by one-step lithography process and had repeated S-shape patterns with a curvature of 280° along the channel. Moreover, the effect of asymmetry was assessed by comparing the mixing results with symmetrical microchannels. Mixing performance was analyzed by using NaOH and phenolphthalein solutions as mixing fluids, which entered from the channel inlets. According to the results, the significant effects of stretching and contracting motion of Dean vortices revealed themselves above a certain Dean number value, thereby making the asymmetrical microchannel outperform the symmetrical channel in the mixing performance. Below this threshold, the symmetrical microchannel was observed to be superior to the asymmetrical microchannel.     

Symbolic pixel labeling for curvilinear feature detection

This paper describes a method of detecting thin curvilinear features in an image based on a detailed analysis of the local gray level patterns at each pixel. This allows operations such as thinning and gap filling to be based on more accurate information.     

High-order curvilinear meshing using a thermo-elastic analogy

With high-order methods becoming increasingly popular in both academia and industry, generating curvilinear meshes that align with the boundaries of complex geometries continues to present a significant challenge. Whereas traditional low-order methods use planar-faced elements, high-order methods introduce curvature into elements that may, if added naively, cause the element to self-intersect. Over the last few years, several curvilinear mesh generation techniques have been designed to tackle this issue, utilizing mesh deformation to move the interior nodes of the mesh in order to accommodate curvature at the boundary. Many of these are based on elastic models, where the mesh is treated as a solid body and deformed according to a linear or non-linear stress tensor. However, such methods typically have no explicit control over the validity of the elements in the resulting mesh. In this article, we present an extension of this elastic formulation, whereby a thermal stress term is introduced to ‘heat’ or ‘cool’ elements as they deform. We outline a proof-of-concept implementation and show that the adoption of a thermo-elastic analogy leads to an additional degree of robustness, by considering examples in both two and three dimensions.