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As computing systems become increasingly pervasive, the number of applications that can benefit from or require localization capabilities continuously increases. In indoor environments, wireless sensor networks are a common means to perform localization, trilateration being one of the most commonly used techniques. The placement of anchor nodes influences greatly the system performance and cost. This...
This paper introduces a Fresnel-like reflector antenna design producing high-order Orbital Angular Momentum states. This design is referred to as a Fresnel-like reflector because the typical surface discontinuity corresponding to the wrapped phase is only applied to the helical shaping and not to the basic parabolic shape so as to maintain broad band operation. This approach is found to provide stronger...
Curvature on the surface of 3D mesh model is an important discrete differential geometrical descriptor. It can show the curving degree very well for those models with curving pieces and the ones with extreme points or extension components. In this paper, we use mean curvature and corresponding coordinates of the vertexes on the surface as the feature descriptor of model. The descriptor we defined...
We present a new shape descriptor, the differential profile, for shape representation and recognition, which is derived from differential and geometric quantities evaluated at points on a shape. We model differential profiles from a class of shapes as a finite mixture of Gaussians, and use an expectation-maximization (EM) procedure for class-wise model learning. Experiments on handwritten digit and...
As a new theory for studying non-linear complex systems, fractal geometry has received much attention recently. Based on the relationship between length of curve and change of scale as well as the idea that a closed curve is formed by a certain amount of unclosed curves, we present an improved Douglas-Peuker method (IDPM) based algorithm. Our algorithm can not only keep the shape and details of the...
Sheet beam is employed in THz devices as the beam offers an effective interaction with the RF signal. Sheet beam gun design is a challenge in achieving required flatness and laminarity over the length of RF-beam interaction. As per the published literature, sheet beam shape is obtained by using complicated shapes of cathode, BFE and anode. In the present work a planar gun geometry has been proposed...
There are several notions of distance between (stable) IIR-filters. The mathematically most promising definition is based on Riemannian geometry. The underlying metric is typically highly warped which makes navigating in such spaces a complicated task. In particular, shortest paths between two given filters can be regarded as geodesics. We present a novel approach that is a combination of three ideas...
Shape spaces can be endowed with the structure of Rieman- nian manifolds; this allows one to compute, for example, Euler-Lagrange equations and geodesic distance for such spaces. Until very recently little was known about the actual geometry of shape manifolds; in this paper we summarize results contained in [1], which deals with the computation of curvature for landmark shape spaces. Implications...
Kernel PCA has received a lot of attention over the past years and showed usefull for many image processing problems. In this paper we analyse the issue of normalization in Kernel PCA for the pre-image problem. We present a geometric interpretation of the normalization process for the gaussian kernel. As a consequence, we could formulate a correct normalization criterion in centered feature space...
3D mesh models generated with range scanner or video images often have holes due to many occlusions by other objects and the object itself. This paper proposes a novel method to fill the missing parts in the incomplete models. The missing parts are filled by minimizing the energy function, which is defined based on similarity of local shape between the missing region and the rest of the object. The...
Images, polygonal models and point clouds are three kinds of heterogeneous cross-media resources, but they can stand for the same object. We introduce two kinds of homogeneous descriptions for them. First, we find a relation between surface moment invariants and shape distribution since they both use invariant geometric primitives. This relation can provide a way to approximate surface moment invariants...
In this paper, a strong emphasis is laid on the study of automatic alignment and registration technology for the purpose of stitching serial images and getting a larger, seamless and high-resolution one. Aerial image taken by robot flying flat has low quality and complex distortion, it is hard to find and evaluate transformation factors in the scene which appeared between the aeronautic consecutive...
Progressive vector data transmission is an import spatial data service for settling the contradiction between the amount of spatial data and network link. Existing work is focus on simplification with map generalization which has some problems. This paper put forward a new way for progressive vector data transmission based on overall effect, not on single geometry object. For this purpose, data model...
We propose a self-adaptive hybrid evolutionary algorithm for the optimization of Morse clusters. The approach relies on a two-phase local optimization method to efficiently guide search. Individuals encode its own penalty settings and the algorithm evolves them simultaneously with the search for low energy clusters. Results show that the approach is efficient, as it is able to discover all optimal...
This paper presents a novel method of contour reconstruction from dexel data solving the shape anomalies for the complex geometry in virtual sculpting. Grouping and traversing processes are developed to find connectivity between dexels along every two adjacent rays. After traveling through all the rays on one slice, sub-boundaries are connected into full boundaries which are desired contours. The...
As the amount of new information generated in the world rapidly increases, efficient search in collections of structured data, texts and multimedia objects. 3D objects are an important type of multimedia data with many applications. Recent developments in techniques for modeling, digitizing and visualizing 3D models have led to an increase in the number of available 3D models on the Internet and in...
Several computer vision algorithms rely on detecting a compact but representative set of interest regions and their associated descriptors from input data. When the input is in the form of an unorganized 3D point cloud, current practice is to compute shape descriptors either exhaustively or at randomly chosen locations using one or more preset neighborhood sizes. Such a strategy ignores the relative...
In the following paper we present a complete analytical model that predicts the band-gap (Eg) of single-walled carbon nanotubes (SWCNTs) directly from their diameter (d) and chiral angle (thetas). The proposed analytical model is based on two mathematical expressions that have been derived by curve-fitting the outcome generated from the third-nearest-neighbor tight-binding (TB) method in conjunction...
The paper presents a target recognition method with magnitude and direction of gradient in mid-resolution optical remote sensing images. Firstly, the directional texture is analyzed and a fast location method based on the gradient blurring process is realized. Secondly, the target characteristic like geography, gray, geometry are analyzed and described. Finally, using the shape character distance,...
Calculating mean envelope is defined as an operation (mean envelope operation) in empirical mode decomposition (EMD). According to the filter bank structure of the bidimensional empirical mode decomposition (BEMD), the hypothesis about the mean envelope operation on the band limited two-dimensional signal is brought out. With this hypothesis, the guess of the BEMD infinite sifting is deduced. In the...
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