Axiomatic Digital Topology

The paper presents a new set of axioms of digital topology, which are easily understandable for application developers. They define a class of locally finite (LF) topological spaces. An important property of LF spaces satisfying the axioms is that the neighborhood relation is antisymmetric and transitive. Therefore any connected and non-trivial LF space is isomorphic to an abstract cell complex. The paper demonstrates that in an n-dimensional digital space only those of the (a, b)-adjacencies commonly used in computer imagery have analogs among the LF spaces, in which a and b are different and one of the adjacencies is the “maximal” one, corresponding to 3 ⁿ − 1 neighbors. Even these (a, b)-adjacencies have important limitations and drawbacks. The most important one is that they are applicable only to binary images. The way of easily using LF spaces in computer imagery on standard orthogonal grids containing only pixels or voxels and no cells of lower dimensions is suggested. Vladimir Kovalevsky received his diploma in physics from the Kharkov University (Ukraine) in 1950, the first doctor degree in technical science from the Central Institute of Metrology (Leningrad) in 1957, the second doctor degree in computer science from the Institute of Cybernetics (Kiev) in 1968. Since 1961 he has been the head of Department of Pattern Recognition at that Institute. Lives since 1980 in Germany. Currently he is professor of computer science at the University of Applied sciences Berlin. His research interest include digital geometry, digital topology, computer vision, image processing and pattern recognition.     

FTP‐SC: Fuzzy Topology Preserving Stroke Correspondence

Stroke correspondence construction is a precondition for vectorized 2D animation inbetweening and remains a challenging problem. This paper introduces the FTP‐SC, a fuzzy topology preserving stroke correspondence technique, which is accurate and provides the user more effective control on the correspondence result than previous matching approaches. The method employs a two‐stage scheme to progressively establish the stroke correspondence construction between the keyframes. In the first stage, the stroke correspondences with high confidence are constructed by enforcing the preservation of the so‐called “fuzzy topology” which encodes intrinsic connectivity among the neighboring strokes. Starting with the high‐confidence correspondences, the second stage performs a greedy matching algorithm to generate a full correspondence between the strokes. Experimental results show that the FTP‐SC outperforms the existing approaches and can establish the stroke correspondence with a reasonable amount of user interaction even for keyframes with large geometric and spatial variations between strokes.     

Topological models for boundary representation: a comparison with n-dimensional generalized maps

In boundary representation, a geometric object is represented by the union of a ‘topological’ model, which describes the topology of the modelled object, and an ‘embedding’ model, which describes the embedding of the object, for instance in three-dimensional Euclidean space. In recent years, numerous topological models have been developed for boundary representation, and there have been important developments with respect to dimension and orientability. In the main, two types of topological models can be distinguished. ‘Incidence graphs’ are graphs or hypergraphs, where the nodes generally represent the cells of the modelled subdivision (vertex, edge, face, etc.), and the edges represent the adjacency and incidence relations between these cells. ‘Ordered’ models use a single type of basic element (more or less explicitly defined), on which ‘element functions’ act; the cells of the modelled subdivision are implicitly defined in this type of model. In this paper some of the most representative ordered topological models are compared using the concepts of the n-dimensional generalized map and the n-dimensional map. The main result is that ordered topological models are (roughly speaking) equivalent with respect to the class of objects which can be modelled (i.e. with respect to dimension and orientability).     

球头铣刀铣削表面形貌建模与仿真

为了研究铣削加工的表面形貌,文章给出了考虑刀杆柔性的螺旋刃球头铣刀的动态铣削过程模型,并基于广义加工表面创成理论、球头铣刀丸线模型和铣削运动模型,对球头刀动态铣削表面形貌进行了建模和仿真。     

A Dynamic Integrated Framework for Software Process Improvement

Current software process models (CMM, SPICE, etc.) strongly recommend the application of statistical control and measure guides to define, implement, and evaluate the effects of different process improvements. However, whilst quantitative modeling has been widely used in other fields, it has not been considered enough in the field of software process improvement. During the last decade software process simulation has been used to address a wide diversity of management problems. Some of these problems are related to strategic management, technology adoption, understanding, training and learning, and risk management, among others. In this work a dynamic integrated framework for software process improvement is presented. This framework combines traditional estimation models with an intensive utilization of dynamic simulation models of the software process. The aim of this framework is to support a qualitative and quantitative assessment for software process improvement and decision making to achieve a higher software development process capability according to the Capability Maturity Model. The concepts underlying this framework have been implemented in a software process improvement tool that has been used in a local software organization. The results obtained and the lessons learned are also presented in this paper.     

Discrete plane segmentation and estimation from a point cloud using local geometric patterns

This paper presents a method for segmenting a 3D point cloud into planar surfaces using recently obtained discretegeometry results. In discrete geometry, a discrete plane is defined as a set of grid points lying between two parallel planes with a small distance, called thickness. In contrast to the continuous case, there exist a finite number of local geometric patterns （LGPs） appearing on discrete planes. Moreover, such an LGP does not possess the unique normal vector but a set of normal vectors. By using those LGP properties, we first reject non-linear points from a point cloud, and then classify non-rejected points whose LGPs have common normal vectors into a planar-surface-point set. From each segmented point set, we also estimate the values of parameters of a discrete plane by minimizing its thickness.     

Toward a Lagrangian Vector Field Topology

In this paper we present an extended critical point concept which allows us to apply vector field topology in the case of unsteady flow. We propose a measure for unsteadiness which describes the rate of change of the velocities in a fluid element over time. This measure allows us to select particles for which topological properties remain intact inside a finite spatio‐temporal neighborhood. One benefit of this approach is that the classification of critical points based on the eigenvalues of the Jacobian remains meaningful. In the steady case the proposed criterion reduces to the classical definition of critical points. As a first step we show that finding an optimal Galilean frame of reference can be obtained implicitly by analyzing the acceleration field. In a second step we show that this can be extended by switching to the Lagrangian frame of reference. This way the criterion can detect critical points moving along intricate trajectories. We analyze the behavior of the proposed criterion based on two analytical vector fields for which a correct solution is defined by their inherent symmetries and present results for numerical vector fields.     

国产民机数字化运营流程管理及仿真系统

数字化运营支持对国际民机领先制造商提高自身市场竞争力、扩大经济效益起到了越来越重要的作用。深入调研国内外数字化运营支持先进技术、经验和发展趋势,针对现有机型ARJ21和C919,梳理了国产数字化运营支持的八大业务场景,重构适合国产民机发展规律的数字化运营支持业务流程。充分考虑数字化、信息化技术发展以及运营支持需求的变化,以及成果的实用性,基于BPMN2.0业务流程建模符号标准和Activiti5流程引擎,搭建业务流程管理及仿真系统,对国产民机数字化运营支持业务流程进行电子化管理,并对典型的维修任务分析作业方法业务流程进行仿真。     

VPML过程模型到面向对象Petri网模型的映射

为了支持对企业业务流程进行建模和分析,辅助过程改进,文章提出了用VPML语言建立过程模型.然后将该过程模型映射为面向对象Petri网模型,通过对Petri网模型的定性分析和模拟仿真,其结果可用于修正和改进模型设计.     

Gothic Town Halls in and around Flanders, 1350-1550: a Geometrical Analysis

Han Vandevyvere undertakes an investigation into some geometrical schemes that can be supposed to underlie the plans and facades of a number of Flemish Gothic town halls, all of them built from the late fourteenth till the early sixteenth century. To govern his study he founded a set of basic ordering rules: a search for simple series of integer numbers, so as to obtain simple ratios between the dimensions; a check to see that what is found to set up a plan is also found in the elevations; the preferential use of geometrical constructions that can easily be constructed with the compass and the carpenter’s square; checking the design in the measurement units that were in use at the moment and place of construction; a check for the use of construction based on a circle, its inscribed square and equilateral triangle.     

Enhancing Urban Façades via LiDAR‐Based Sculpting

Buildings with symmetrical façades are ubiquitous in urban landscapes and detailed models of these buildings enhance the visual realism of digital urban scenes. However, a vast majority of the existing urban building models in web‐based 3D maps such as Google earth are either less detailed or heavily rely on texturing to render the details. We present a new framework for enhancing the details of such coarse models, using the geometry and symmetry inferred from the light detection and ranging (LiDAR) scans and 2D templates. The user‐defined 2D templates, referred to as coded planar meshes (CPMs), encodes the geometry of the smallest repeating 3D structures of the façades via face codes. Our encoding scheme, take into account the directions, type as well as the offset distance of the sculpting to be applied at the respective locations on the coarse model. In our approach, LiDAR scan is registered with the coarse models taken from Google earth 3D or Bing maps 3D and decomposed into dominant planar segments (each representing the frontal or lateral walls of the building). The façade segments are then split into horizontal and vertical tiles using a weighted point count function defined over the window or door boundaries. This is followed by an automatic identification of CPM locations with the help of a template fitting algorithm that respects the alignment regularity as well as the inter‐element spacing on the façade layout. Finally, 3D boolean sculpting operations are applied over the boxes induced by CPMs and the coarse model, and a detailed 3D model is generated. The proposed framework is capable of modelling details even with occluded scans and enhances not only the frontal façades (facing to the streets) but also the lateral façades of the buildings. We demonstrate the potentials of the proposed framework by providing several examples of enhanced Google earth models and highlight the advantages of our method when designing photo‐realistic urban façades.     

On the design and implementation of a geometric-object-oriented language

This paper presents the design and implementation of a geometric-object-oriented language Gool for constructing, representing, manipulating, and visualizing symbolic geometric objects and relations and performing symbolic geometric computation and formal reasoning. The language uses case distinction to formalize symbolic geometric objects and relations, reducing the problem of dealing with uncertainty and degeneracy to that of handling geometric constraints. We describe the capabilities, features, and main components of Gool, propose several techniques for geometric constraint handling, and discuss some of the implementation issues.     

Selection strategies in a structural design support system

This paper presents two selection strategies for the process of establishing a structural design support system. The distinct difference between the strategies is the point of time when the decision maker participates in the design process. The first strategy is called the pre-selection strategy in which the designer tries to grasp the intention or preference of the decision maker at an early stage of the design, and the second one is called the post-selection strategy in which the designer prepares all design information as much as possible, and then the decision maker selects the final design solution. Based on these two strategies, the shared and essential processes of the structural design support system will be explicated in advance, and then the characteristics of these two strategies will be compared. The crucial parts of the structural design support system are common design process that is shared in the two strategies and the alternative based design approach. The common design process means the basic sequences of the design process, such as problem specification, concept design, preliminary design and selection of the final design solution, that are used conventionally in the general design process. These design processes are carried out with the screened region of the design alternatives, which is efficient and effective for the selection of the final design solution. With these concepts, the structural design support system especially the grid-like type structures will be examined and the usefulness of our design methodology will be confirmed. Received October 14, 1999     

Efficient Interpolation of Articulated Shapes Using Mixed Shape Spaces

Interpolation between compatible triangle meshes that represent different poses of some object is a fundamental operation in geometry processing. A common approach is to consider the static input shapes as points in a suitable shape space and then use simple linear interpolation in this space to find an interpolated shape. In this paper, we present a new interpolation technique that is particularly tailored for meshes that represent articulated shapes. It is up to an order of magnitude faster than state‐of‐the‐art methods and gives very similar results. To achieve this, our approach introduces a novel shape space that takes advantage of the underlying structure of articulated shapes and distinguishes between rigid parts and non‐rigid joints. This allows us to use fast vertex interpolation on the rigid parts and resort to comparatively slow edge‐based interpolation only for the joints.     

B超图象PACS系统的研制

介绍了Ｂ超图象ＰＡＣＳ系统的研制过程中的一些主要技术,分别从景象的获取与分析,信息存档及访问,系统通信ＤＩＣＯＭ标准化几个方面加以详细解释。并针对当前ＰＡＣＳ系统存在的一些缺陷提出了解决方法。     

Segmentation of ultrasound images by using a hybrid neural network

A hybrid neural network is presented for the segmentation of ultrasound images.

Feature vectors are formed by the discrete cosine transform of pixel intensities in region of interest (ROI). The elements and the dimension of the feature vectors are determined by considering only two parameters: The amount of ignored coefficients, and the dimension of the ROI.

First-layer-nodes of the proposed hybrid network represent hyperspheres (HSs) in the feature space. Feature space is partitioned by intersecting these HSs to represent the distribution of classes. The locations and radii of the HSs are found by the genetic algorithms.

Restricted Coulomb energy (RCE) network, modified RCE network, multi-layer perceptron and the proposed hybrid neural network are examined comparatively for the segmentation of ultrasound images.     

故障诊断专家系统中的PC机与过程计算机间数据通信的实现

本文介绍了ＰＣ机与过程计算机间如何实现正确数据通信的方法。其中ＰＣ机作为上位机,用于运行故障诊断专家系统;过程计算机是德国西门子ＳＩＥＭＥＮＳ Ｒ３０过程计算机,用来监测和控制某钢厂大型冷轧自动化生产线。该方法既保证了故障诊断专家系统对过程计算机及整个生产线实时地进行状态监测和故障,又不影响过程计算机本身对生产过程的监测和控制。     

混合式教学在“过程控制”课程中的应用

结合“过程控制”课程的教学实践与探索,介绍了该课程中应用混合式教学的目的,具体实施的方法与过程,以及思政元素的融入等。结合教学成果分析,对混合式教学模式进行教学反思,总结经验并发现问题。结果表明,混合式教学所取得的教学效果更佳,基本达到教学改革的目的。     

基于BP神经网络的烧结矿化学成分预报模型与仿真

烧结矿化学成分的测量是钢铁工业中的关键和难点,并且容易受到烧结几乎每一个操作环节的影响。本文利用BP神经网络建立烧结矿化学成分的预报模型。通过对现场实际数据进行仿真,表明该方法鲁棒性强,准确性高,泛化能力广,具有很强的实用性和推广价值。     

A fast algorithm for automatic segmentation and extraction of a single object by active surfaces

Segmentation is an important problem in various applications. There exist many effective models designed to locate all features and their boundaries in an image. However such global models are not suitable for automatically detecting a single object among many objects of an image, because nearby objects are often selected as well. Several recent works can provide selective segmentation capability but unfortunately when generalized to three dimensions, they are not yet effective or efficient. This paper presents a selective segmentation model which is inherently suited for efficient implementation. With the added solver by a fast nonlinear multigrid method for the inside domain of a zero level set function, the over methodology leads to an effective and efficient algorithm for 3D selective segmentation. Numerical experiments show that our model can produce efficient results in terms of segmentation quality and reliability for a large class of 3D images.