a bayesian variable selection approach for analyzing designed experiments with complex aliasing experiments using designs with complex aliasing patterns are often performed for example twolevel nongeometric plackett burman designs multilevel and mixed level fractional factorial designs two level fractional factorial designs with hard to control factors and supersaturated designs hamada and wu proposed an iterative guided stepwise regression strategy for analyzing the data from such designs that allows entertainment of interactions their strategy provides a restricted search in a rather large model space however this article provides an efficient methodology based on a bayesian variable selection algorithm for searching the model space more thoroughly we show how the use of hierarchical priors provides a flexible and powerful way to focus the search on a reasonable class of models the proposed methodology is demonstrated with four examples three of which come from actual industrial experiments

some risks in the construction and analysis of supersaturated designs a designed experiment in which the number of factors is at least as large as the number of runs is referred to as a supersaturated ss design recently these designs have received increased attention construction of such designs and analysis of data from them have been discussed by several authors our objective in this article is to examine these designs and methods for their analysis an important finding for practitioners is that the correlation structure inherent in ss designs can obscure real effects or promote nonreal effects whatever analysis method is used this problem can occur although all subsets regression is preferable to stepwise regression hence one should be cautious with the use of ss designs

the distribution function of the effective field of the ising spin glass on the bethe lattice for the coordination number z 4 5 6 abstract the integral equation for the effective fields of the spin glass is solved analytically for the j ising model on the bether lattice with coordination number z 4 5 and 6 and symmetric distribution functions are obtained the paramagnetic distribution spin glass distribution with three delta functions and spin glass distributions with a continuous distribution are obtained the effect of the truncation of the algebraic equation for solving the integral equation is discussed

snakes active contour models a snake is an energy minimizing spline guided by external constraint forces and influenced by image forces that pull it toward features such as lines and edges snakes are active contour models they lock onto nearby edges localizing them accurately scale space continuation can be used to enlarge the capture region surrounding a feature snakes provide a unified account of a number of visual problems including detection of edges lines and subjective contours motion tracking and stereo matching we have used snakes successfully for interactive interpretation in which user imposed constraint forces guide the snake near features of interest

motion and structure from orthographic projections s ullman s classical 1979 results on motion structure from orthographic views are revisited specifically two results are presented 1 two orthographic views allow an uncountably infinite number of solutions to motion structure of a rigid body and 2 a linear algorithm for solving motion structure from four point correspondences over three views

graph partitioning and dilute spin glasses the minimum cost solution the authors calculate the ground state cost function energy for graph bipartitioning and spin glasses on networks with fixed finite valences allowing a continuous distribution for the effective field compared with previous calculations using a field distribution in integral multiples of the coupling strength j the ground state energy is higher by less than one per cent although the distribution itself is altered drastically

using the folded over 12 run plackett burman design to consider interactions this article demonstrates that the folded over 12 run plackett burman design is useful for considering up to 12 factors in 24 runs even if one anticipates that some two factor interactions may be significant the properties of this design are investigated and a sequential procedure for analyzing the data from such a design is proposed the performance of the procedure is investigated through the analysis of real and constructed examples and through a small simulation study applications to other folded over plackett burman designs are also briefly discussed

3d motion recovery via affine epipolar geometry 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

some comments on cp i study the typical configuration of a cp plot when the number of variables in the regression problem is large and there are many weak effects i show that a particular configuration that is very commonly seen can arise in a simple way i give a formula by means of which the risk incurred by the minimum cp rule can be estimated

nonregular designs with desirable projection properties in many industrial applications the experimenter is interested in estimating some of the main effects and two factor interactions in this article we rank two level orthogonal designs based on the number of estimable models containing a subset of main effects and their associated two factor interactions by ranking designs in this way the experimenter can directly assess the usefulness of the experimental plan for the purpose in mind we apply the new ranking criterion to the class of all non isomorphic two level orthogonal designs with 16 and 20 runs and introduce a computationally efficient algorithm based on two theoretical results which will aid in finding designs with larger run sizes catalogs of useful designs with 16 20 24 and 28 runs are presented

the free energy at t 0 of the spin glass in the case of the continuous distribution of the effective field on the bethe lattice for z 4 5 6 abstract we evaluated the free energy at t 0 of the j random ising model on the bethe lattice of the coordination number z 4 5 6 in the case where the distribution function of the effective field has a continuous distribution by using the method of the integral equation of the effective field

benefits and fast construction of efficient two level foldover designs recent work in two level screening experiments has demonstrated the advantages of using small foldover designs even when such designs are not orthogonal for the estimation of main effects mes i

quick and easy analysis of unreplicated factorials box and meyer 1986 introduced a method for assessing the sizes of contrasts in unreplicated factorial and fractional factorial designs this is a useful technique and an associated graphical display popularly known as a bayes plot makes it even more effective this article presents a competing technique that is also effective and is computationally simple an advantage of the new method is that the results are given in terms of the original units of measurement this direct association with the data may make the analysis easier to explain

polyhedral object localization in an image by referencing to a single model view identifying a three dimensional 3d object in an image is traditionally dealt with by referencing to a 3d model of the object in the last few years there has been a growing interest of using not a 3d shape but multiple views of the object as the reference this paper attempts a further step in the direction using not multiple views but a single clean view as the reference model the key issue is how to establish correspondences from the model view where the boundary of the object is explicitly available to the scene view where the object can be surrounded by various distracting entities and its boundary disturbed by noise we propose a solution to the problem which is based upon a mechanism of predicting correspondences from just four particular initial point correspondences the object is required to be polyhedral or near polyhedral the correspondence mechanism has a computational complexity linear with respect to the total number of visible corners of the object in the model view the limitation of the mechanism is also analyzed thoroughly in this paper experimental results over real images are presented to illustrate the performance of the proposed solution

applications of tensor theory to object recognition and orientation determination a method is developed by which images resulting from orthogonal projection of rigid planar patch objects arbitrarily oriented in three dimensional 3 d space may be used to form systems of linear equations which are solved for the affine transform relating the images the technique is applicable to complete images and to unlabeled feature sets derived from images and with small modification may be used to transform images of unknown objects such that they represent images of those objects from a known orientation for use in object identification no knowledge of point correspondence between images is required theoretical development of the method and experimental results are presented the method is shown to be computationally efficient requiring o n multiplications and additions where depending on the computation algorithm n may equal the number of object or edge picture elements

incorporating prior information in optimal design for model selection an important use of experimental designs is in screening in which experimenters seek to identify significant effects both main effects and potentially interactions from a large set of candidate effects this article goes further than identification of effects introducing a design criterion that seeks to maximize the ability to discriminate between models motivated by the work of meyer steinberg and box the bayesian criterion is based on the hellinger distance between predictive distributions under competing models a bound for the criterion is obtained greatly improving interpretability the set of all possible models to compare is huge and not all models are equally plausible this challenge is addressed through prior distributions on the space of models that indicate preference for intuitively appealing models such as those with few effects more low order than high order effects and inheritance structure between active main effects and interactions techniques for evaluating the criterion a

recognizing solid objects by alignment with an image in this paper we consider the problem of recognizing solid objects from a single two dimensional image of a three dimensional scene we develop a new method for computing a transformation from a three dimensional model coordinate frame to the two dimensional image coordinate frame using three pairs of model and image points we show that this transformation always exists for three noncollinear points and is unique up to a reflective ambiguity the solution method is closed form and only involves second order equations we have implemented a recognition system that uses this transformation method to determine possible alignments of a model with an image each of these hypothesized matches is verified by comparing the entire edge contours of the aligned object with the image edges using the entire edge contours for verification rather than a few local feature points reduces the chance of finding false matches the system has been tested on partly occluded objects in highly cluttered scenes

irgs image segmentation using edge penalties and region growing this paper proposes an image segmentation method named iterative region growing using semantics irgs which is characterized by two aspects first it uses graduated increased edge penalty giep functions within the traditional markov random field mrf context model in formulating the objective functions second irgs uses a region growing technique in searching for the solutions to these objective functions the proposed irgs is an improvement over traditional mrf based approaches in that the edge strength information is utilized and a more stable estimation of model parameters is achieved moreover the irgs method provides the possibility of building a hierarchical representation of the image content and allows various region features and even domain knowledge to be incorporated in the segmentation process the algorithm has been successfully tested on several artificial images and synthetic aperture radar sar images

algebraic functions for recognition in the general case a trilinear relationship between three perspective views is shown to exist the trilinearity result is shown to be of much practical use in visual recognition by alignment yielding a direct reprojection method that cuts through the computations of camera transformation scene structure and epipolar geometry moreover the direct method is linear and sets a new lower theoretical bound on the minimal number of points that are required for a linear solution for the task of reprojection the proof of the central result may be of further interest as it demonstrates certain regularities across homographics of the plane and introduces new view invariants experiments on simulated and real image data were conducted including a comparative analysis with epipolar intersection and the linear combination methods with results indicating a greater degree of robustness in practice and a higher level of performance in reprojection tasks

recognition by linear combinations of models an approach to visual object recognition in which a 3d object is represented by the linear combination of 2d images of the object is proposed it is shown that for objects with sharp edges as well as with smooth bounding contours the set of possible images of a given object is embedded in a linear space spanned by a small number of views for objects with sharp edges the linear combination representation is exact for objects with smooth boundaries it is an approximation that often holds over a wide range of viewing angles rigid transformations with or without scaling can be distinguished from more general linear transformations of the object by testing certain constraints placed on the coefficients of the linear combinations three alternative methods of determining the transformation that matches a model to a given image are proposed

zero temperature hysteresis in the random field ising model on a bethe lattice we consider the single spin flip dynamics of the random field ising model on a bethe lattice at zero temperature in the presence of a uniform external field we determine the average magnetization as the external field is varied from to by setting up the self consistent field equations which we show are exact in this case the qualitative behaviour of magnetization as a function of the external field unexpectedly depends on the coordination number z of the bethe lattice for z 3 with a gaussian distribution of the quenched random fields we find no jump in magnetization for any non zero strength of disorder for for weak disorder the magnetization shows a jump discontinuity as a function of the external uniform field which disappears for a larger variance of the quenched field we determine exactly the critical point separating smooth hysteresis curves from those with a jump we have checked our results by monte carlo simulations of the model on three and four coordinated random graphs which for large system sizes give the same results as on the bethe lattice but avoid surface effects altogether

construction of two level nonregular designs of strength three with large run sizes abstracttwo level orthogonal arrays of strength 3 permit the study of the main effects and the two factor interactions of the experimental factors these arrays are classified into regular and nonr

the quadric reference surface theory and applications the conceptual component of this work is about reference surfaces which are the analogous to reference frames often used for shape representation purposes the theoretical component of this work involves the question of whether one can find a unique and simple mapping that aligns two arbitrary perspective views of an opaque textured quadric surface in 3d given i few corresponding points in the two views or ii the outline conic of the surface in one view only and few corresponding points in the two views the practical component of this work is concerned with applying the theoretical results as tools for the task of achieving full correspondence between views of arbitrary objects

optimal foldover plans for two level nonregular orthogonal designs this article considers optimal foldover plans for nonregular designs by using the indicator function we define words with fractional lengths the extended word length pattern is then used to select among nonregular foldover designs some general properties of foldover designs are obtained using the indicator function we prove that the full foldover plan that reverses the signs of all factors is optimal for all 12 run and 20 run orthogonal designs the optimal foldover plans for all 16 run regular and nonregular orthogonal designs are constructed and tabulated for practical use optimal foldover plans for higher order orthogonal designs can be constructed in a similar manner

optimal semifoldover plans for two level orthogonal designs foldover is a widely used procedure for selecting follow up experimental runs as foldover designs require twice as many runs as the initial design they can be inefficient if the number of effects to be de aliased is smaller than the size of the original experiment semifolding refers to adding half of a foldover fraction and is a technique that has been investigated in recent literature for regular two level fractional factorial designs as an alternative to foldover in this article semifoldover plans for two level orthogonal factorial designs regular and nonregular are compared and ranked based on the concept of minimal dependent sets optimal plans are developed for selected 12 16 20 and 32 run designs a hidden projection property of optimal semifoldovers of 12 and 20 run orthogonal arrays is uncovered general properties of semifoldover designs are also discussed all initial designs considered in this article are included in the supplementary files available online