10114388
O(1) Time Algorithm on BSR for Constructing a Binary Search Tree with Best Frequencies
Constructing a binary search tree of n nodes with best frequencies needs Ω(n log n) time on RAM, and Ω(log n) time on n-processor EREW, CREW, or CRCW PRAM. In this paper, we propose an O(1) time algorithm on n-processor BSR PRAM for the problem, which is the first constant time solution to the problem on any model of computation.
11974123
Practical 3-D Shape Measurement Using Optimal Intensity-Modulated Projection and Intensity-Phase Analysis Techniques
In the field of 3D image measurement, a technique based on stripe pattern projection and observation image intensity analysis is expected to be able to detect several stripes by a single projection. It is necessary to increase the stripe number of the projection pattern in order to improve the measurement accuracy of depth distance. However, when the stripe number is increased, the difference of the intensity between stripes will be reduced and stripe detection will become difficult. In order to improve the detection accuracy of the stripe order and shorten the 3D measurement time, we use the optimal intensity-modulation projection (OIMP) technique, and in order to improve the depth distance measurement accuracy, we propose an intensity-phase analysis (IPA) technique. In the proposed IPA technique, the observation pattern be segmented by the intensity of the intensity-modulated stripe, and in every segmentation the depth distance of all pixels are obtained by phase analysis. By using a combination of the OIMP and IPA techniques, high-speed (single projection and double image captures) and high-accuracy (error less than 0.1%) practical 3D shape measurement can be realized
30370540
On (d, 2)-dominating numbers of binary undirected de Bruijn graphs
Abstract In this paper, we show that: (i) For n-dimensional undirected binary de Bruijn graphs, UB(n), n⩾4, there is a vertex x=x 1 x 1 x 1 ⋯ x 1 x 1 (x1=1 or 0) such that for any other vertex t there exist at least two internally disjoint paths of length at most n−1 between x and t in UB(n), i.e., the (n−1,2)-dominating number of UB(n) is equal to one. (ii) For n⩾5, let S={100⋯01,011⋯10}. For any other vertex t there exist at least two internally disjoint paths of length at most n−2 between t and S in UB(n), i.e., the (n−2,2)-dominating number of UB(n) is no more than 2.
6462272
Intrinsic Images by Entropy Minimization
A method was recently devised for the recovery of an invariant image from a 3-band colour image. The invariant image, originally 1D greyscale but here derived as a 2D chromaticity, is independent of lighting, and also has shading removed: it forms an intrinsic image that may be used as a guide in recovering colour images that are independent of illumination conditions. Invariance to illuminant colour and intensity means that such images are free of shadows, as well, to a good degree. The method devised finds an intrinsic reflectivity image based on assumptions of Lambertian reflectance, approximately Planckian lighting, and fairly narrowband camera sensors. Nevertheless, the method works well when these assumptions do not hold. A crucial piece of information is the angle for an “invariant direction” in a log-chromaticity space. To date, we have gleaned this information via a preliminary calibration routine, using the camera involved to capture images of a colour target under different lights. In this paper, we show that we can in fact dispense with the calibration step, by recognizing a simple but important fact: the correct projection is that which minimizes entropy in the resulting invariant image. To show that this must be the case we first consider synthetic images, and then apply the method to real images. We show that not only does a correct shadow-free image emerge, but also that the angle found agrees with that recovered from a calibration. As a result, we can find shadow-free images for images with unknown camera, and the method is applied successfully to remove shadows from unsourced imagery.
7786870
Construction of a hierarchical classifier schema using a combination of text-based and image-based approaches
Web document hierarchical classification approaches often rely on textual features alone even though web pages include multimedia data. We propose a new hierarchical integrated web classification approach that combines image-based and text-based approaches. Instead of using a flat classifier to combine text and image classification, we perform classification on a hierarchy differently on different levels of the tree, using text for branches and images only at leaves. The results of our experiments show that the use of the hierarchical structure improved web document classification performance significantly.
2968463
Making Data Mining Models Useful to Model Non-paying Customers of Exchange Carriers
Due to both limitations of technologies and the nature of the problems, data mining may not be able to solve a problem completely in a way as one wishes. When this happens, we need to first understand the actual need of business, characteristic of available partial solution, and then make compromises between the technology solution and business needs. A majority of the papers published in data mining conferences and journals seem to concentrate only on the success side of the story. In this paper, we discuss our experiences and the complete process from near failure to success when applying inductive learning techniques to predict non-paying customers of competitive local exchange carriers (CLEC’s), currently at 20%. Experiments with a number of stateof-the-art methods and algorithms found that most customers were labeled as paying on time. Cost-sensitive learning is not possible since the target company cannot define a cost-model. Finally, after discussing with the billing department, a compromised but still useful solution is to predict the probability that someone will default. The billing team can use the predicted score to prioritize collection efforts as well as to predict cash flow. We have found that two randomized decision tree ensemble methods (Fan’s random decision tree and a probabilistic extension of Breiman’s random forest) are consistently more accurate in posterior probability estimation than single decision tree based probability calibration methods. The software, both Fan’s RDT and probabilistic extension of random forest, as well as a longer version of this paper will be made available by the contacting author.
17196005
Analysis of payment transaction security in mobile commerce
Mobile payment is the process of two parties exchanging financial value using a mobile device in return for goods or services. This paper is an analysis of the security issues in mobile payment for m-commerce. We introduce m-commerce and mobile payment, discuss the public key infrastructure as a basis for secure mobile technologies, and study the features for different security technologies employed in current m-commerce market, including WAP, SIM application toolkit and J2M. In addition, we compare the effectiveness of these security technologies in supporting a secure mobile payment, and discuss research issues to enhance the security of mobile payment for large scale deployment of m-commerce.