Reducing control points in surface interpolation

Surface interpolation to rectangularly arranged points is an integral part of surface design and modeling in CAD/CAM and graphics. Using B-spline surfaces, the process involves curve interpolations through rows of data points and through columns of control points. This method, as well tuned as it is, proves inadequate for recent problems such as those of reverse engineering. Data acquisition devices, such as scanners, may be used to return rows of data points, but it's not guaranteed that each row contains the same number of points. The problem then arises of passing a smooth surface through these points (assuming that interpolation is justified, meaning the number of points isn't large). Since each row contains different numbers of points, regular data interpolation can't be used. One method to solve this problem is to interpolate each row with B-spline curves and to pass a smooth surface through these curves via surface skinning. While this is a legitimate solution, the number of control points tends to become prohibitively large, especially if the number of rows is large. This article addresses the problem of how to reduce the number of control points while maintaining precise interpolation. The idea is to give the knots some flexibility so that each row can be interpolated with as few new knots added as possible     

P(VDF-TrFE) copolymer acoustic emission sensors

Acoustic emission (AE) sensors have been fabricated using polarized polyvinylidene fluoride/trifluoroethylene (P(VDF-TrFE)) piezoelectric copolymer films. The acoustic and electromechanical properties of the copolymers have been determined using the ultrasonic immersion technique and the resonance technique, respectively. The P(VDF-TrFE) AE sensors have been calibrated according to the ASTM standard and evaluated for potential application in the detection of AE in glass fiber reinforced polypropylene (GFPP). A ceramic AE sensor also has been fabricated using lead zirconate titanate (PZT) 7A piezoelectric ceramic and its sensitivity and performance are reported as well. The copolymer sensors do not show resonance peaks of the ceramic sensor and have adequate sensitivity. They can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.     

Locality-preserved maximum information projection.

Dimensionality reduction is usually involved in the domains of artificial intelligence and machine learning. Linear projection of features is of particular interest for dimensionality reduction since it is simple to calculate and analytically analyze. In this paper, we propose an essentially linear projection technique, called locality-preserved maximum information projection (LPMIP), to identify the underlying manifold structure of a data set. LPMIP considers both the within-locality and the between-locality in the processing of manifold learning. Equivalently, the goal of LPMIP is to preserve the local structure while maximize the out-of-locality (global) information of the samples simultaneously. Different from principal component analysis (PCA) that aims to preserve the global information and locality-preserving projections (LPPs) that is in favor of preserving the local structure of the data set, LPMIP seeks a tradeoff between the global and local structures, which is adjusted by a parameter alpha, so as to find a subspace that detects the intrinsic manifold structure for classification tasks. Computationally, by constructing the adjacency matrix, LPMIP is formulated as an eigenvalue problem. LPMIP yields orthogonal basis functions, and completely avoids the singularity problem as it exists in LPP. Further, we develop an efficient and stable LPMIP/QR algorithm for implementing LPMIP, especially, on high-dimensional data set. Theoretical analysis shows that conventional linear projection methods such as (weighted) PCA, maximum margin criterion (MMC), linear discriminant analysis (LDA), and LPP could be derived from the LPMIP framework by setting different graph models and constraints. Extensive experiments on face, digit, and facial expression recognition show the effectiveness of the proposed LPMIP method.     

The impact of process standardization on business process outsourcing success

What is the impact of business process standardization on business process outsourcing (BPO) success? This paper argues that there is a direct impact of process standardization on BPO success, due to production cost economies, and also an indirect effect via improved contractual and relational governance resulting from better monitoring opportunities and facilitated communication and coordination. This threefold impact of standardization on BPO success is empirically confirmed using data from 335 BPO ventures in 215 German banks.     

Evaluation of Localization Attacks on Power-Modulated Challenge–Response Systems

Location information should be verifiable in order to support new computing and information services. In this paper, we adapt the classical challenge-response method for authentication to the task of verifying an entity's location. Our scheme utilizes a collection of transmitters, and adapts the power allocations across these transmitters to verify a user's claimed location. This strategy, which we call a power-modulated challenge response, is able to be used with existing. wireless sensor networks. First, we propose a direct method, where some transmitters are selected to send ldquochallengesrdquo that the claimant node should be able to witness based on its claimed location, and for which the claimant node must correctly respond to in order to prove its location. Second, we reverse the strategy by presenting an indirect method, where some transmitters send challenges that the claimant node should not be able to witness. Then, we present a signal-strength-based method, where the node responds with its received signal strength and thereby provides improved location verification. To evaluate our schemes, we examine different adversarial models for the claimant, and characterize the performance of our power-modulated challenge response schemes under these adversarial models. Further, we propose a new localization attack, where a set of nodes collaborates to pretend that there is a node at the claimed location. This collusion attack can do tremendous harm to localization and the performance of the aforementined methods under collusion attack are explained. Finally, we propose the use of a rotational directional power-modulated challenge response, where directional antennas are used to defend against collusion attacks.     

Polarized light imaging of white matter architecture

Polarized light imaging (PLI) is a method to image fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method uses the transmission of polarized light to quantitatively estimate the fiber orientation and inclination angles at every point of the imaged section. Multiple sections can be assembled into a 3D volume, from which the 3D extent of fiber tracts can be extracted. This article describes the physical principles of PLI and describes two major applications of the method: the imaging of white matter orientation of the rat brain and the generation of fiber orientation maps of the human brain in white and gray matter. The strengths and weaknesses of the method are set out.     

Interface with angels: the future of VIR and AR interfaces

Although real guardian angels aren't easy to get hold of, some of the computer technology needed for such a personal assistant is already available. Other parts exist in the form of research prototypes, but some technological breakthroughs are necessary before we can realize their potential, let alone integrate into our daily routines. Future VR and AR interfaces won't necessarily try to provide a perfect imitation of reality but instead will adapt their display mechanisms to their users' individual requirements. The emergence of these interfaces won't rely on a single technology but will depend on the advances in many areas, including computer graphics, display technology, tracking and recognition devices, natural and intuitive interactions, 3D interaction techniques, mobile and ubiquitous computing, intelligent agents, and conversational user interfaces, to name a few. The guardian angel scenario exemplifies how future developments in AR and VR user interfaces might change the way we interact with computers. Although this example is just one of several plausible scenarios, it demonstrates that AR and VP, in combination with user-centered design of their post-WIMP interfaces, can provide increased access, convenience, usability, and efficiency     

Semiautomated finite element mesh generation methods for a long bone

The objective of this work was to develop and test a semi-automated finite element mesh generation method using computed tomography (CT) image data of a canine radius. The present study employs a direct conversion from CT Hounsfield units to elastic moduli. Our method attempts to minimize user interaction and eliminate the need for mesh smoothing to produce a model suitable for finite element analysis. Validation of the computational model was conducted by loading the CT-imaged canine radius in four-point bending and using strain gages to record resultant strains that were then compared to strains calculated with the computational model. Geometry-based and uniform modulus voxel-based models were also constructed from the same imaging data set and compared. The nonuniform voxel-based model most accurately predicted the axial strain response of the sample bone (R(2)=0.9764).