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Many high level representations of time series have been proposed for data mining, including Fourier transforms, wavelets, eigenwaves, piecewise polynomial models, etc. Many researchers have also considered symbolic representations of time series, noting that such representations would potentiality allow researchers to avail of the wealth of data structures(More)
Many algorithms have been proposed for the problem of time series classification. However, it is clear that one-nearest-neighbor with Dynamic Time Warping (DTW) distance is exceptionally difficult to beat. This approach has one weakness, however; it is computationally too demanding for many realtime applications. One way to mitigate this problem is to speed(More)
The problem of time series classification has attracted great interest in the last decade. However current research assumes the existence of large amounts of <i>labeled</i> training data. In reality, such data may be very difficult or expensive to obtain. For example, it may require the time and expertise of cardiologists, space launch technicians, or other(More)
The matching of two-dimensional shapes is an important problem with applications in domains as diverse as biometrics, industry, medicine and anthropology. The distance measure used must be invariant to many distortions, including scale, offset, noise, partial occlusion, etc. Most of these distortions are relatively easy to handle, either in the(More)
The vast majority of data mining algorithms require the setting of many input parameters. The dangers of working with parameter-laden algorithms are twofold. First, incorrect settings may cause an algorithm to fail in finding the true patterns. Second, a perhaps more insidious problem is that the algorithm may report spurious patterns that do not really(More)
Over the past three decades, there has been a great deal of research on shape analysis, focusing mostly on shape indexing, clustering, and classification. In this work, we introduce the new problem of finding shape discords, the most unusual shapes in a collection. We motivate the problem by considering the utility of shape discords in diverse domains(More)
The comments, opinions, and views expressed in the paper do not necessarily reflect those of the members, directors, and officers of the New York Stock Exchange, Inc. All errors and omissions are the authors' own. Abstract Have structural changes in the U.S. equities markets, such as decimalization, the growth of ECNs, and improvements in order routing(More)
Video data security is very important for multimedia commerce such as video-on-demand and real-time video multicast. Nowadays, many video encryption methods have been put forward. This paper presents a new kind of video encryption approach that based on the syntax character of compressed digital video bitstreams. Using this approach, we can shuffle the(More)