Aesthetic layout of generalized trees

Research on the aesthetic layout of trees has been largely concerned with the special case of binary trees with small constant-sized nodes. Yet, without otherwise requiring the power of general graph-layout algorithms, many layout problems involve n-ary trees with variable-sized nodes. This paper addresses the general issue of the aesthetic layout of such trees. Two algorithms are presented for the layout of generalized trees, and general issues, such as appropriate aesthetics, are discussed. The algorithms described are suitable for such tasks as the layout of class hierarchies, directory trees and tableau-style proofs.     

Automatic metro map layout using multicriteria optimization

This paper describes an automatic mechanism for drawing metro maps. We apply multicriteria optimization to find effective placement of stations with a good line layout and to label the map unambiguously. A number of metrics are defined, which are used in a weighted sum to find a fitness value for a layout of the map. A hill climbing optimizer is used to reduce the fitness value, and find improved map layouts. To avoid local minima, we apply clustering techniques to the map-the hill climber moves both stations and clusters when finding improved layouts. We show the method applied to a number of metro maps, and describe an empirical study that provides some quantitative evidence that automatically-drawn metro maps can help users to find routes more efficiently than either published maps or undistorted maps. Moreover, we have found that, in these cases, study subjects indicate a preference for automatically-drawn maps over the alternatives.     

Library layout via graph theory

This article reports on a case study of the design of the new Law library at the University of Canterbury in New Zealand. The objective was to produce a layout which attempts to minimize expected travel and is convenient for all users, including librarians. The problem differed from most layout studies in two ways. There are three identifiable groups of users of the library: the librarians, the students, and the law professors. Also, the intensity of travel between facilities in the library is location dependent. None of the existing layout methods that the authors tried seemed capable of producing a suitable layout. Using graph theory, the authors developed and implemented a flexible layout approach which led to a successful design. This article summarizes the steps involved, including obtaining a compromise layout which satisfied the needs of the three groups of users.     

An optimal emulator and VLSI layout for complete binary trees

How complex does a graph need to be in order to emulate an arbitrary size complete binary tree with the same level of efficiency as would be obtained by a directed complete graph? In this paper, this question is answered by showing that any -node graph needs to have at least edges in order to perform this emulation. Subsequently, a graph is presented which meets this bound, and it is shown how to optimally embed an arbitrary size complete binary tree in the proposed graph. It is also shown how to optimally embed a node cycle in the proposed graph of nodes with unit dilation, unit congestion and uniform load of . Finally optimal VLSI layouts are presented for the proposed graph which require asymptotically same area as the corresponding layouts for complete binary trees. Received: 7 July 1994 / 28 May 1996     

Comparing trees via crossing minimization

We consider the following problem (and variants thereof) that has important applications in the construction and evaluation of phylogenetic trees: Two rooted unordered binary trees with the same number of leaves have to be embedded in two layers in the plane such that the leaves are aligned in two adjacent layers. Additional matching edges between the leaves give a one-to-one correspondence between pairs of leaves of the different trees. Our goal is to find two planar embeddings of the two trees (drawn without crossings) that minimize the number of crossings of the matching edges. We derive both (classical) complexity results and (parameterized) algorithms for this problem (and some variants thereof).¹     

基于布局图的多物体场景新视角图像生成网络

新视角图像生成任务指通过多幅参考图像,生成场景新视角图像。然而多物体场景存在物体间遮挡,物体信息获取不全,导致生成的新视角场景图像存在伪影、错位问题。为解决该问题,提出一种借助场景布局图指导的新视角图像生成网络,并标注了全新的多物体场景数据集（multi-objects novel view Synthesis,MONVS）。首先,将场景的多个布局图信息和对应的相机位姿信息输入到布局图预测模块,计算出新视角下的场景布局图信息;然后,利用场景中标注的物体边界框信息构建不同物体的对象集合,借助像素预测模块生成新视角场景下的各个物体信息;最后,将得到的新视角布局图和各个物体信息输入到场景生成器中构建新视角下的场景图像。在MONVS和ShapeNet cars数据集上与最新的几种方法进行了比较,实验数据和可视化结果表明,在多物体场景的新视角图像生成中,所提方法在两个数据集上都有较好的效果表现,有效地解决了生成图像中存在伪影和多物体在场景中位置信息不准确的问题。     

Depth map inpainting via sparse distortion model

The depth map captured from a real scene by the Kinect motion sensor is always influenced by noise and other environmental factors. As a result, some depth information is missing from the map. This distortion of the depth map directly deteriorates the quality of the virtual viewpoints rendered in 3D video systems. We propose a depth map inpainting algorithm based on a sparse distortion model. First, we train the sparse distortion model using the distortion and real depth maps to obtain two learning dictionaries: one for distortion and one for real depth maps. Second, the sparse coefficients of the distortion and the real depth maps are calculated by orthogonal matching pursuit. We obtain the approximate features of the distortion from the relationship between the learning dictionary and the sparse coefficients of the distortion map. The noisy images are filtered by the joint space structure filter, and the extraction factor is obtained from the resulting image by the extraction factor judgment method. Finally, we combine the learning dictionary and sparse coefficients from the real depth map with the extraction factor to repair the distortion in the depth map. A quality evaluation method is proposed for the original real depth maps with missing pixels. The proposed method achieves better results than comparable methods in terms of depth inpainting and the subjective quality of the rendered virtual viewpoints.     

Line drawing via saliency map and ETF

Line drawing is a means of superior visual communication which can effectively convey useful information to viewers. Artists usually draw what they see rather than what exists, which means the most attractive object is emphasized while the rest are inhibited. Moreover, artists draw the whole object with coherent lines instead of fractured lines, which also contribute to the outstanding visual effect. From these perspectives, generating line drawings with saliency and coherence remains a great challenge. Existing line drawing generation methods ignore these important properties and cannot generate coherent lines in some cases since they do not take into account how artists draw a picture. To this end, a novel saliency-aware line drawing method was proposed to better grasp the viewer’s attention on an image. First, a saliency enhanced line extraction method combining saliency map and edge tangent flow was proposed to ensure the saliency and coherence of lines, especially in salient but low contrast areas. Then, the salient information was highlighted while irrelevant details were eliminated by inhibiting lines in less salient areas to enhance the saliency of the line drawing. Finally, the transparency of lines was adjusted to further emphasize important information. Various results showed that our method can generate line drawings with better visual saliency and coherence than the state-of-the-art methods.     

Flow field analysis in a spiral viscous micropump

The paper presents a stream function solution and a computational analysis for the flow field of a viscous spiral pump, which employs a rotating spiral channel to achieve pumping action. This pump is fabricated using surface micromachining technology. The stream function solution employs a simplified 2D model for the flow field in its spiral channel that neglects the curvature of the spiral, and replaces it with an equivalent straight channel. The effect of spiral wall height on flow rate is analyzed and discussed. 3D computational analyses are obtained and are compared with analytical predictions.     

Controllable procedural map generation via multiobjective evolution

This paper shows how multiobjective evolutionary algorithms can be used to procedurally generate complete and playable maps for real-time strategy (RTS) games. We devise heuristic objective functions that measure properties of maps that impact important aspects of gameplay experience. To show the generality of our approach, we design two different evolvable map representations, one for an imaginary generic strategy game based on heightmaps, and one for the classic RTS game StarCraft. The effect of combining tuples or triples of the objective functions are investigated in systematic experiments, in particular which of the objectives are partially conflicting. A selection of generated maps are visually evaluated by a population of skilled StarCraft players, confirming that most of our objectives correspond to perceived gameplay qualities. Our method could be used to completely automate in-game controlled map generation, enabling player-adaptive games, or as a design support tool for human designers.     

Person search via class activation map transferring

Multimedia Tools and Applications - The methods to tackle person search problem can be divided into two categories. One is to train an end-to-end person search model to search target person from...     

基于自适应权值滤波的深度图像超分辨率重建

目的 越来越多的应用都依赖于对真实场景深度图像的准确且快速的观测和分析。飞行时间相机可以实时获取场景的深度图像,但是由于硬件条件的限制,采集的深度图像分辨率较低,无法满足实际应用的需要。为此提出一种结合同场景彩色图像通过构造自适应权值滤波器对深度图像进行超分辨率重建的方法。方法 充分发掘深度图像的非局部以及局部自相似性先验约束,结合同场景的高分辨率彩色图像构造非局部及局部的自适应权值滤波算法对深度图像进行超分辨率重建。具体来说,首先利用非局部滤波算法来有效避免重建结果的振铃效应,然后利用局部滤波算法进一步提升重建的深度图像质量。结果 实验结果表明,无论在客观指标还是视觉效果上,基于自适应权值滤波的超分辨率重建算法较其他算法都可以得到更好的结果,尤其当初始的低分辨率深度图像质量较差的情况下,本文方法的优势更加明显,峰值信噪比可以得到1dB的提升。结论 结合非局部和局部自相似性先验约束,结合同场景的高分辨率彩色图像构造的自适应权值滤波算法,较其他算法可以得到更理想的结果。     

Flow equivalent trees in undirected node-edge-capacitated planar graphs

Given an edge-capacitated undirected graph G=(V,E,C) with edge capacity , n=|V|, an s−t edge cut C of G is a minimal subset of edges whose removal from G will separate s from t in the resulting graph, and the capacity sum of the edges in C is the cut value of C. A minimum s−t edge cut is an s−t edge cut with the minimum cut value among all s−t edge cuts. A theorem given by Gomory and Hu states that there are only n−1 distinct values among the n(n−1)/2 minimum edge cuts in an edge-capacitated undirected graph G, and these distinct cuts can be compactly represented by a tree with the same node set as G, which is referred to the flow equivalent tree. In this paper we generalize their result to the node-edge cuts in a node-edge-capacitated undirected planar graph. We show that there is a flow equivalent tree for node-edge-capacitated undirected planar graphs, which represents the minimum node-edge cut for any pair of nodes in the graph through a novel transformation.     

Minimum spanning trees made easier via multi-objective optimization

Many real-world problems are multi-objective optimization problems and evolutionary algorithms are quite successful on such problems. Since the task is to compute or approximate the Pareto front, multi-objective optimization problems are considered as more difficult than single-objective problems. One should not forget that the fitness vector with respect to more than one objective contains more information that in principle can direct the search of evolutionary algorithms. Therefore, it is possible that a single-objective problem can be solved more efficiently via a generalized multi-objective model of the problem. That this is indeed the case is proved by investigating the computation of minimum spanning trees.This work was supported by the Deutsche Forschungsgemeinschaft (DFG) as part of the Collaborative Research Center Computational Intelligence (SFB 531) and by the German-Israeli Foundation (GIF) in the project Robustness Aspects of Algorithms.     

Multipurpose watermarking scheme via intelligent method and chaotic map

Multimedia Tools and Applications - In this paper, we propose a novel multipurpose intelligent image watermarking scheme for both content authentication and copyright protection. To achieve this,...     

Externalizing cognitive maps via map reconstruction and verbal description

Universal Access in the Information Society - Helping blind people to build cognitive maps of an environment is one of the aims of several assistive systems. In order to evaluate such assistive...     

Hypotrochoid spiral optimization approach for sizing and layout optimization of truss structures with multiple frequency constraints

Engineering with Computers - The primary aim of this article is to present a new improved version of the spiral optimization algorithm (SPO) for shape and size optimization of truss structures...