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31.
Larry R. DeJarnett 《Information Systems Management》2013,30(1):81-84
Abstract This issue's column on IS strategy presents the results of a recent survey on the state of strategic planning in U.S. companies. 相似文献
32.
33.
3D Motion recovery via affine Epipolar geometry 总被引:10,自引:6,他引:4
Larry S. Shapiro Andrew Zisserman Michael Brady 《International Journal of Computer Vision》1995,16(2):147-182
Algorithms to perform point-based motion estimation under orthographic and scaled orthographic projection abound in the literature. A key limitation of many existing algorithms is that they operate on the minimum amount of data required, often requiring the selection of a suitable minimal set from the available data to serve as a local coordinate frame. Such approaches are extremely sensitive to errors and noise in the minimal set, and forfeit the advantages of using the full data set. Furthermore, attention is seldom paid to the statistical performance of the algorithms.We present a new framework that allowsall available features to be used in the motion computations, without the need to select a frame explicitly. This theory is derived in the context of theaffine camera, which preserves parallelism and generalises the orthographic, scaled orthographic and para-perspective models. We define the affine epipolar geometry for two such cameras, giving the fundamental matrix in this case. The noise resistant computation of the epipolar geometry is discussed, and a statistical noise model constructed so that confidence in the results can be assessed.The rigid motion parameters are then determineddirectly from the epipolar geometry, using the novel rotation representation of Koenderink and van Doorn (1991). The two-view partial motion solution comprises the scale factor between views, the projection of the 3D axis of rotation and the cyclotorsion angle, while the addition of a third view allows the true 3D rotation axis to be computed (up to a Necker reversal). The computed uncertainties in these parameters permit optimal estimates to be obtained over time by means of a linear Kalman filter. Our theory extends work by Huang and Lee (1989), Harris (1990), and Koenderink and van Doorn (1991), and results are given on both simulated and real data. 相似文献
34.
David A. Bader Joseph Jájá David Harwood Larry S. Davis 《The Journal of supercomputing》1996,10(2):141-168
This paper presents efficient and portable implementations of a powerful image enhancement process, the Symmetric Neighborhood Filter (SNF), and an image segmentation technique that makes use of the SNF and a variant of the conventional connected components algorithm which we call -Connected Components. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The image segmentation algorithm makes use of an efficient connected components algorithm based on a novel approach for parallel merging. The algorithms have been coded in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, IBM SP-1 and SP-2, Cray Research T3D, Meiko Scientific CS-2, Intel Paragon, and workstation clusters. Our experimental results are consistent with the theoretical analysis (and provide the best known execution times for segmentation, even when compared with machine-specific implementations). Our test data include difficult images from the Landsat Thematic Mapper (TM) satellite data.Also affiliated with the Department of Electrical Engineering.Also affiliated with the Department of Computer Science and the Center for Automation Research. 相似文献
35.
Han Bohyung Zhu Ying Comaniciu Dorin Davis Larry S. 《IEEE transactions on pattern analysis and machine intelligence》2009,31(5):919-930
Particle filtering is frequently used for visual tracking problems since it provides a general framework for estimating and propagating probability density functions for nonlinear and non-Gaussian dynamic systems. However, this algorithm is based on a Monte Carlo approach and the cost of sampling and measurement is a problematic issue, especially for high-dimensional problems. We describe an alternative to the classical particle filter in which the underlying density function has an analytic representation for better approximation and effective propagation. The techniques of density interpolation and density approximation are introduced to represent the likelihood and the posterior densities with Gaussian mixtures, where all relevant parameters are automatically determined. The proposed analytic approach is shown to perform more efficiently in sampling in high-dimensional space. We apply the algorithm to real-time tracking problems and demonstrate its performance on real video sequences as well as synthetic examples. 相似文献
36.
Gupta Abhinav Kembhavi Aniruddha Davis Larry S. 《IEEE transactions on pattern analysis and machine intelligence》2009,31(10):1775-1789
Interpretation of images and videos containing humans interacting with different objects is a daunting task. It involves understanding scene/event, analyzing human movements, recognizing manipulable objects, and observing the effect of the human movement on those objects. While each of these perceptual tasks can be conducted independently, recognition rate improves when interactions between them are considered. Motivated by psychological studies of human perception, we present a Bayesian approach which integrates various perceptual tasks involved in understanding human-object interactions. Previous approaches to object and action recognition rely on static shape/appearance feature matching and motion analysis, respectively. Our approach goes beyond these traditional approaches and applies spatial and functional constraints on each of the perceptual elements for coherent semantic interpretation. Such constraints allow us to recognize objects and actions when the appearances are not discriminative enough. We also demonstrate the use of such constraints in recognition of actions from static images without using any motion information. 相似文献
37.
Jay Smith Vladimir Shestak Howard Jay Siegel Suzy Price Larry Teklits Prasanna Sugavanam 《Parallel Computing》2009,35(7):389-400
Recently there has been an increased demand for imaging systems in support of high-speed digital printing. The required increase in performance in support of such systems can be accomplished through an effective parallel execution of image processing applications in a distributed cluster computing environment. The output of the system must be presented to a raster based display at regular intervals, effectively establishing a hard deadline for the production of each image. Failure to complete a rasterization task before its deadline will result in an interruption of service that is unacceptable. The goal of this research was to derive a metric for measuring robustness in this environment and to design a resource allocation heuristic capable of completing each rasterization task before its assigned deadline, thus, preventing any service interruptions. We present a mathematical model of such a cluster based raster imaging system, derive a robustness metric for evaluating heuristics in this environment, and demonstrate using the metric to make resource allocation decisions. The heuristics are evaluated within a simulation of the studied raster imaging system. We clearly demonstrate the effectiveness of the heuristics by comparing their results with the results of a resource allocation heuristic commonly used in this type of system. 相似文献
38.
The inability to engage with systems risk during the development of integrated socio-technical systems presents a real threat to global and local socio-economic stability. Current theories on system risk engagement are driven by a functionalist orthodoxy. Accordingly, risk management is either non-existent, done in parallel to other development activity, or used by organisations as an instrument of control. Systems risk management needs to be addressed at the source of the problem: the systems engineering process. This paper addresses the predominant failure to appropriately engage with systems risk during development. It provides, with respect to the theoretical dimensions, a diversity of risk perspectives, complexity and socio-technical systems theory. A broad literature review on different risk concepts, risk management perspectives and organisational paradigms (functionalist, interpretive, radical humanist and radical structuralist) is also presented. In order to overcome a lack of a holistic and reflective risk management approach to systems development, this paper sketches an integrated soft systems methodology approach which can be used for engaging with systems risk during systems development. 相似文献
39.
It is believed that mammalian chemosensory irritants are not aversive to birds and vice versa. Nevertheless, few avian repellents have been tested against mammals. For that reason, we evaluated the efficacy of 1.0% w/v methyl anthranilate, orthoaminoacetophenone, 2-amino-4,5-methoxyacetophenone, 2-methoxyacetophenone, and veratryl amine as mouse repellents in 3-hr no-choice drinking tests. Relative to ingestion of plain water, all test substances significantly reduced (P < 0.05) intake. Orthoaminoaceto-phenone was the most effective repellent, with intake reduced to levels statistically indistinguishable from zero. 相似文献
40.
Studied the relationship between 2 construct subsystems, one for construing people and one for defining a concrete social situation. Using a variant of G. Kelly's grid methodology, 20 college students rated 12 personal acquaintances on 12 constructs of bipolar concepts. They were then presented with 1 of 2 problematic social situations and asked to rate the same acquaintances on 10 dimensions relevant to the situation. Principal-components analysis was used to derive 1 central and 2 secondary patterns of construing (centrality being defined by the amount of variance the component accounts for on a grid), as well as 1 central and 2 secondary dimensions defining the social situation. Cross-correlations between the orderings of people on these 2 sets of components were used to determine the extent to which "implicit personality theory" influenced the definition of a situation. Findings show that central construing related strongly to the central definition of a situation, whereas secondary construing related more weakly to secondary definitions. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献