作者：
Dutilleul, PMcGill Univ
Dept Plant Sci Lab Appl Stat Ste Anne De Bellevue PQ H9X 3V9 Canada
The maximum likelihood estimation (MLE) of the parameters of the matrix normal distribution is considered, In the absence of analytical solutions of the system of likelihood equations for the among-row and among-colum...
详细信息
The maximum likelihood estimation (MLE) of the parameters of the matrix normal distribution is considered, In the absence of analytical solutions of the system of likelihood equations for the among-row and among-column covariance matrices, a two-stage algorithm must be solved to obtain their maximum likelihood estimators. A necessary and sufficient condition for the existence of maximum likelihood estimators is given and the question of their stability as solutions of the system of likelihood equations is addressed. In particular, the covariance matrix parameters and their maximum likelihood estimators are defined up to a positive multiplicative constant;only their direct product is uniquely defined. Using simulated data under two variance-covariance structures that, otherwise, are indistinguishable by semivariance analysis, further specific aspects of the procedure are studied: (1) the convergence of the MLE algorithm is assessed;(2) the empirical bias of the direct product of covariance matrix estimators is calculated for various sample sizes;and (3) the consistency of the estimator is evaluated by its mean Euclidean distance from the parameter, as a function of the sample size. The adequacy of the matrix normal model, including the separability of the variance-covariance structure, is tested on multiple time series of dental medicine data;other applications to real doubly multivariate data are outlined.
In this paper, we discuss a nonadaptive group testing algorithm that identifies up to two defects. The number of required tests in our algorithm is not optimal, but our search procedure is less complex than that of ot...
详细信息
In this paper, we discuss a nonadaptive group testing algorithm that identifies up to two defects. The number of required tests in our algorithm is not optimal, but our search procedure is less complex than that of other well known algorithms using fewer tests. We go on to discuss a simple twostage modification of our algorithm which dramatically reduces the number of sufficient tests. (C) 1998 Elsevier Science B.V.
We use a simple, but nonstandard, incidence relation to construct probabilistic nonadaptive group testing algorithms that identify many positives in a population with a zero probability of yielding a false positive. M...
详细信息
We use a simple, but nonstandard, incidence relation to construct probabilistic nonadaptive group testing algorithms that identify many positives in a population with a zero probability of yielding a false positive. More importantly, we give two-stage modifications of our nonadaptive algorithms that dramatically reduce the expected number of sufficient pools. For our algorithms, we give a lower bound on the probability of identifying all the positives and we compute the expected number of positives identified. Our method gives control over the pool sizes. In DNA library screening algorithms, where relatively small pools are generally preferred, having control over the pool sizes is an important practical consideration.
A two-stage algorithm for matching line segments using three-dimensional data is presented. In the first stage, a tree-search based on the orientation of the line segments is applied to establish potential matches. th...
详细信息
A two-stage algorithm for matching line segments using three-dimensional data is presented. In the first stage, a tree-search based on the orientation of the line segments is applied to establish potential matches. the sign ambiguity of line segments is fixed by a simple congruency constraint. In the second stage, a Hough clustering technique based on the position of line segments is applied to verify potential matches. Any paired line segments of a match that cannot be brought to overlap by the translation determined by the clustering are removed from the match. Unlike previous methods, this algorithm combats noise more effectively, and ensures the global consistency of a match. While the original motivation for the algorithm is multiple-object motion estimation from stereo image sequences, the algorithm can also be applied to other domains, such as object recognition and object model construction from multiple views.","doi":"10.1109/34.58872","publicationTitle":"IEEE Transactions on Pattern Analysis and Machine Intelligence","startPage":"1002","endPage":"1008","rightsLink":"http://***/AppDispatchServlet?publisherName=ieee&publication=0162-8828&title=Matching+3-D+line+segments+with+applications+to+multiple-object+motion+estimation&isbn=&publicationDate=Oct.+1990&author=H.H.+Chen&ContentID=10.1109/34.58872&orderBeanReset=true&startPage=1002&endPage=1008&volumeNum=12&issueNum=10","displayPublicationTitle":"IEEE Transactions on Pattern Analysis and Machine Intelligence","pdfPath":"/iel1/34/2141/***","keywords":[{"type":"IEEE Keywords","kwd":["Motion estimation","Stereo vision","Image sequences","Motion analysis","Clustering algorithms","Testing","Image recognition","Image motion analysis","Object recognition","Computer vision"]},{"type":"INSPEC: Controlled Indexing","kwd":["trees (mathematics)","pattern recognition","search problems"]},{"type":"INSPEC: Non-Controlled Indexing","kwd":["object model construction","pattern recognition","3-D line s
A technique for finding the solution of discrete, multistate dynamic programming problems is applied to solve certain variational problems. The algorithm is a method of successive approximations using a general two-st...
详细信息
A technique for finding the solution of discrete, multistate dynamic programming problems is applied to solve certain variational problems. The algorithm is a method of successive approximations using a general two-stage solution. The advantage of the method is that it provides a means of reducing Bellman's “curse of dimensionality.” An example on the Plateau problem or the minimal surface area problem is considered, and the algorithm is found to be computationally efficient.
暂无评论