Showing papers on "Matching (statistics) published in 1994"
TL;DR: In this article, the authors present an efficient indexing method to locate 1-dimensional subsequences within a collection of sequences, such that the subsequences match a given (query) pattern within a specified tolerance.
Abstract: We present an efficient indexing method to locate 1-dimensional subsequences within a collection of sequences, such that the subsequences match a given (query) pattern within a specified tolerance....
422 citations
01 Jan 1994
TL;DR: A generic model of matching that can be usefully applied to misuse intrusion detection, based on Colored Petri Nets, with main benefits of its generality, portability and flexibility.
Abstract: This paper describes a generic model of matching that can be usefully applied to misuse intrusion detection. The model is based on Colored Petri Nets. Guards define the context in which signatures are matched. The notion of start and final states, and paths between them define the set of event sequences matched by the net. Partial order matching can also be specified in this model. The main benefits of the model are its generality, portability and flexibility.
420 citations
TL;DR: Urn randomization is randomization that is systematically based in favor of balancing that preserves randomization as the primary basis for assignment to treatment and is less susceptible to experimenter bias or manipulation of the allocation process by staff than is balancing.
Abstract: In comparative or matching research involving two or more treatments, the equivalence of the patient groups is of critical importance. In the past, equivalence has either been imposed by matching or balancing, or has been assured statistically by randomization. Matching and balancing, while useful in many contexts, nonetheless have important limitations, as does simple randomization. In recent years, a new tool has been developed that represents a compromise between balancing and randomization. This method, urn randomization, gives clinical investigators new options for improving the credibility of studies at a relatively modest cost. Urn randomization is randomization that is systematically based in favor of balancing. It can be used with several covariates, both marginally and jointly, producing optimal multivariate equivalence of treatment groups for large sample sizes. It preserves randomization as the primary basis for assignment to treatment and is less susceptible to experimenter bias or manipulation of the allocation process by staff than is balancing. Disadvantages include the fact that it is more difficult to implement, and that it violates the simple probability model of simple randomization. A number of research studies on addictions, including client-treatment matching trials, have used urn randomization. A summary of the mechanics of urn randomization is presented, and guidelines for its use in treatment studies are discussed.
420 citations
TL;DR: An algorithm is derived that isolates the coherent structures of a signal and describes an application to pattern extraction from noisy signals, using a greedy algorithm called a matching pursuit, which computes a suboptimal expansion.
Abstract: Computing the optimal expansion of a signal in a redundant dictionary of waveforms is an NP-hard problem. We introduce a greedy algorithm, called a matching pursuit, which computes a suboptimal expansion. The dictionary waveforms that best match a signal's structures are chosen iteratively. An orthogonalized version of the matching pursuit is also developed. Matching pursuits are general procedures for computing adaptive signal representations. With a dictionary of Gabor functions, a matching pursuit defines an adaptive time-frequency transform. Matching pursuits are chaotic maps whose attractors define a generic noise with respect to the dictionary. We derive an algorithm that isolates the coherent structures of a signal and describe an application to pattern extraction from noisy signals.
381 citations
TL;DR: In this article, the authors describe polynomial-time algorithms that will establish, in either of these two cases, whether a matching of the appropriate kind exists, and if so will find such a matching.
281 citations
01 Jan 1994
TL;DR: A generalized model for matching intrusion signatures based on Colored Petri Nets is presented, and some of its properties are derived.
Abstract: This report examines and classi es the characteristics of signatures used in misuse intrusion detection. E cient algorithms to match patterns in some of these classes are described. A generalized model for matching intrusion signatures based on Colored Petri Nets is presented, and some of its properties are derived.
207 citations
TL;DR: This paper presents a system, called approximate-tree-by-example (ATBE), which allows inexact matching of trees, and describes the architecture of ATBE, its use and describes some aspects ofATBE implementation.
Abstract: Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has any) is fixed. Such trees have many applications in vision, pattern recognition, molecular biology, programming compilation, and natural language processing. Many of the applications involve comparing trees or retrieving/extracting information from a repository of trees. Examples include classification of unknown patterns, analysis of newly sequenced RNA structures, semantic taxonomy for dictionary definitions, generation of interpreters for nonprocedural programming languages, and automatic error recovery and correction for programming languages. Previous systems use exact matching (or generalized regular expression matching) for tree comparison. This paper presents a system, called approximate-tree-by-example (ATBE), which allows inexact matching of trees. The ATBE system interacts with the user through a simple but powerful query language; graphical devices are provided to facilitate inputing the queries. The paper describes the architecture of ATBE, illustrates its use and describes some aspects of ATBE implementation. We also discuss the underlying algorithms and provide some sample applications. >
182 citations
01 Jan 1994
TL;DR: In this paper, the authors present case studies of wind-diesel systems and evaluate the economics index of the wind resource and their suitability for different types of diesel generators and generators.
Abstract: How to use this book 1. Wind-diesel system options 2. Matching the wind-diesel system to the community 3. Assessing the wind resource 4. Designing a system 5. Wind-diesel case studies 6. Modelling techniques and model validation 7. Installing and monitoring of wind-diesel systems 8. Assessing the economics Index.
173 citations
Posted Content•
TL;DR: In this article, the authors analyzed the effect of three dimensions of choice on the specification and power of test-statistics designed to detect abnormal operating performance: (1) the selection of a performance measures (e.g., return on assets or return on sales), (2) the choice of a statistical test, and (3) selection of performance benchmark (where they evaluate nine different performance benchmarks).
Abstract: Many recent studies have analyzed the impact that corporate events or managerial decisions have on operating performance. In these studies, researchers face many methodological choices. This paper analyzes the effect that three dimensions of choice have on the specification and power of test-statistics designed to detect abnormal operating performance: (1) the selection of a performance measures (e.g. return on assets or return on sales), (2) the selection of a statistical test (e.g., parametric t-statistic or non-parametric Wilcoxon T*), and (3) the selection of a performance benchmark (where we evaluate nine different performance benchmarks). On the first two dimensions (choice of performance measures and statistical test) we generally find little difference in the specification and power of test-statistics. However, on the third dimension (choice of performance benchmark), only one benchmark -- matching sample firms to firms with the same two-digit SIC code and similar past performance -- is well-specified. In the conclusion, we provide specific recommendations about the choice of performance measure, test-statistic, and benchmark.
154 citations
28 Feb 1994
TL;DR: This paper introduces a novel instruction-set matching and selection methodology, based upon a rich representation useful for DSP and mixed control-oriented applications, implemented in a retargetable code generation system called CodeSyn.
Abstract: The increasing use of digital signal processors (DSPs) and application specific instruction-set processors (ASIPs) has put a strain on the perceived mature state of compiler technology The presence of custom hardware for application-specific needs has introduced instruction types which are unfamiliar to the capabilities of traditional compilers Thus, these traditional techniques can lead to inefficient and sparsely compacted machine microcode In this paper, we introduce a novel instruction-set matching and selection methodology, based upon a rich representation useful for DSP and mixed control-oriented applications This representation shows explicit behaviour that references architecture resource classes This allows a wide range of instructions types to be captured in a pattern set The pattern set has been organized in a manner such that matching is extremely efficient and retargeting to architectures with new instruction sets is well defined The matching and selection algorithms have been implemented in a retargetable code generation system called CodeSyn >
150 citations
TL;DR: This work builds upon the seminal work of Kishon et al. (1990), where curves are first smoothed using B-splines, with matching based on hashing using curvature and torsion measures, but introduces two enhancements that allow a more accurate estimation of position, curvature, torsions, and Frénet frames along the curve.
Abstract: We present a new approach to the problem of matching 3-D curves. The approach has a low algorithmic complexity in the number of models, and can operate in the presence of noise and partial occlusions. Our method builds upon the seminal work of Kishon et al. (1990), where curves are first smoothed using B-splines, with matching based on hashing using curvature and torsion measures. However, we introduce two enhancements:
We present experimental results using synthetic data and also using characteristic curves extracted from 3-D medical images. An earlier version of this article was presented at the 2nd European Conference on Computer Vision in Italy.
TL;DR: A list of generic layout rules and a layout scheme that predict matching accuracies better than 0.1% for the individual systematic error sources using capacitor sizes in the range of 20-40 /spl mu/m are developed.
Abstract: Precise capacitor ratios are employed in a variety of analog and mixed signal integrated circuits. The use of identical unit capacitors to form larger capacitances can easily produce 1% accuracy, but, in many cases, 0.1% accuracy can provide important performance advantages. Unfortunately, the ultimate matching precision of the ratio is limited by a number of systematic and random error sources. We have analyzed the source and significance of the systematic error sources on actual integrated circuit layouts and isolated five key contributors. Based on this analysis, we have developed a list of generic layout rules and a layout scheme that predict matching accuracies better than 0.1% for the individual systematic error sources using capacitor sizes in the range of 20-40 /spl mu/m. >
TL;DR: A variety of new information technologies have emerged that clearly can improve the efficiency and effectiveness of marketing programs as mentioned in this paper, however, the use of technologies such as computer matching or computer matching is limited.
Abstract: A variety of new information technologies have emerged that clearly can improve the efficiency and effectiveness of marketing programs. However, the use of technologies such as computer matching or...
TL;DR: In this paper, the effectiveness of three different search channels: advertisements, public employment office, and informal channels is analyzed, and the matching functions are estimated using market level data and micro data on vacancy duration and job search duration.
Abstract: The authors analyze the effectiveness of three different search channels: advertisements, public employment office, and informal channels. Their approach integrates search on both sides of the labor market. For each search channel, the authors specify matching functions in which the number of vacancies and the number of searchers in that market are input variables. The effectiveness of the search channels can be assessed on the basis of the estimated parameters of the matching functions. The matching functions are estimated using market level data and micro data on vacancy duration and job search duration. Copyright 1994 by Royal Economic Society.
TL;DR: Alternative habitat matching rules based on ideal distribution models of density-dependent habitat use are developed that can be applied to a wide array of ideal forms of habitat selection, including the ideal free, continuous input example.
Abstract: I evaluate habitat matching rules based on ideal distribution models of density-dependent habitat use. Recent approaches and the ideal free continuous input matching rule on which they depend, are restricted to only those habitats that are jointly occupied across the full range of population sizes. These assumptions may often be inappropriate to field applications of habitat matching. I develop alternatives that can be applied to a wide array of ideal forms of habitat selection, including the ideal free, continuous input example. Input matching can be distinguished from assumptions of consumer-resource models and preemptive habitat use by regressions of density between paired habitats (isodars). Isodars for continuous input models should be linear on a logarithmic scale, while those for consumer-resource models should be linear on an arithmetic scale. Pre-emptive isodars can be distinguished from the others by dramatic non-linearities at both low and high densities. Field data on white-footed mice support the consumer-resource theory. Implications of the rules for population regulation and community organization are highlighted by new models that specify how the fitness of pre-emptive habitat selectors should decline with increasing density. Strong non-linearities produced by comparisons between variable and homogeneous habitats produce reversing source-sink population regulation and a new form of cyclical community dynamics. Variable habitats act as a source of emigrants at low density and a sink for immigrants at high density. Subordinate species may occupy only the variable habitat at both low and high density.
09 Sep 1994
TL;DR: It is demonstrated that, with a simple preprocessing step for the Computed Tomography (CT) images, grey value correlation can be used for matching of Magnetic Resonance Imaging (MRI) with CT images and the method is robust and accurate.
Abstract: Grey value correlation is generally considered not to be applicable to matching of images of different modalities. In this paper we will demonstrate that, with a simple preprocessing step for the Computed Tomography (CT) images, grey value correlation can be used for matching of Magnetic Resonance Imaging (MRI) with CT images. Two simple schemes are presented for automated 3D matching of MRI and CT neuroradiological images. Both schemes involve grey value correlation of the images in order to determine the matching transformation. In both schemes the preprocessing consists of a simple intensity mapping of the original CT image only. It will be shown that the results are insensitive to considerable changes in the parameters that determine the intensity mapping. Whichever preprocessing step is chosen, the correlation method is robust and accurate. Results, compared with a skin marker-based matching technique, are shown for brain images. Additionally, results are shown for an entirely new application: matching of the cervical spine.
Patent•
18 Mar 1994TL;DR: An electronic dealing system which performs foreign exchange transactions among banks etc. by matching terms of sale and terms of purchase, provided with a leave-order function whereby a dealing terminal may continue to place orders on the market and automatically perform transactions even after log-out processing as mentioned in this paper.
Abstract: An electronic dealing system which performs foreign exchange transactions among banks etc. by matching terms of sale and terms of purchase, provided with a leave-order function whereby a dealing terminal may continue to place orders on the market and automatically perform transactions even after log-out processing. This enables transactions to be safely performed even when the operator is not present.
TL;DR: Thirty-one empirical studies on "client-treatment matching" are reviewed, particularly from the perspective of how research methodology in this area has evolved, and several promising interactions between client characteristics and particular interventions are noted.
Abstract: During the past 20 years researchers have become increasingly interested in exploring the benefits of differential assignment of alcoholics to treatments based on client-specific characteristics, rather than searching for a single "most effective" intervention for all clients. Thirty-one empirical studies on "client-treatment matching" are reviewed, particularly from the perspective of how research methodology in this area has evolved. In addition, general observations are provided on how research methodology on this topic can be further enhanced. Finally, several promising interactions between client characteristics and particular interventions are noted, based on empirical studies to date.
TL;DR: Three adolescent students with special educational needs were given a choice between completing one of two available sets of math problems, and Reinforcers across these alternatives were arranged systematically in separate experimental phases according to three different concurrent variable-interval schedules.
Abstract: Three adolescent students with special educational needs were given a choice between completing one of two available sets of math problems. Reinforcers (nickels) across these alternatives were arranged systematically in separate experimental phases according to three different concurrent variable-interval schedules (reinforcement ratios of 2:1, 6:1, and 12:1). Time allocated to the two stacks of math problems stood in linear relationship to the reinforcement rate obtained from each stack, although substantial undermatching and bias were observed for all subjects. However, changes in the schedules were not followed by changes in allocation patterns until adjunct procedures (e.g., changeover delays, limited holds, timers, and demonstrations) were introduced. The necessity of adjunct procedures in establishing matching in applied situations is discussed as a limitation to quantitative applications of the matching law in applied behavior analysis.
TL;DR: The strategies used in Project MATCH are described, which include: strategies for treating a variety of alcoholics within a single treatment approach; development of clinical care guidelines and clinical deterioration criteria; specification of treatments in manuals with minimization of overlapping active ingredients; and extensive therapist training and monitoring.
Abstract: Treatment matching research is predicated on heterogeneity among subjects and their differential response to treatments. The sine qua non of a treatment matching study is the integrity of the treatment variable, since detection of client-treatment interactions requires delivery of treatments that are highly specific, consistent and distinct. Matching research thus presents particular challenges in treatment implementation, as greater heterogeneity in subjects may generate a broader array of problems than study treatments are designed to address, leading to several potential threats to treatment integrity. Moreover, as practiced outside of research settings, treatments for alcoholism are marked by ideological heterogeneity and a lack of purity across approaches. In this article we describe the strategies used in Project MATCH to protect treatment integrity while treating a large and heterogeneous sample of alcoholics in a number of geographically distant sites. These include: strategies for treating a vari...
TL;DR: A stratified version of nested case-control sampling which is called "countermatching" is presented, and asymptotic relative efficiency calculations indicate that a substantial efficiency gain relative to simple random sampling of controls can be expected in these situations.
Abstract: A stratified version of nested case-control sampling which we call "countermatching" is presented This design uses data available for all cohort members to obtain a sample for collecting additional information in a case-control substudy Hitherto the only stratified sampling design for such studies has involved matching of controls to cases with respect to confounding variables However, in some situations, rather than sampling to make controls as similar as possible to cases, we might wish to make them as different as possible This is achieved by the counter-matched design Statistical analysis of counter-matched studies is straightforward using existing computer software We investigate the use of the design when a surrogate measure of exposure is available for the full cohort, but accurate exposure data is to be collected only in a nested case-control study, and when exposure data are available for the whole cohort but data concerning important confounders are not Asymptotic relative efficiency calculations indicate that a substantial efficiency gain relative to simple random sampling of controls can be expected in these situations We also illustrate how the design might be implemented in practice
TL;DR: This paper describes an iterative technique for gradually deforming a mask binary image with successive local affine transformation (LAT) operations so as to yield the best match to an input binary image as one new and promising approach toward robust handwritten character recognition.
Abstract: This paper describes an iterative technique for gradually deforming a mask binary image with successive local affine transformation (LAT) operations so as to yield the best match to an input binary image as one new and promising approach toward robust handwritten character recognition. The method uses local shapes in the sense that the LAT of each point at one location is optimized using locations of other points by means of least-squares data fitting using Gaussian window functions. It also uses a multiscale refinement technique that decreases the spread of window functions with each iteration. Especially in handwritten character recognition, structural information is indispensable for robust shape matching or discrimination. The method is enhanced to explicitly incorporate structures by weighting the above least-squares criterion with similarity measures of both topological and geometric features of the mask and input images. Moreover, deformation constraints are imposed on each iteration, not only to promote and stabilize matching convergence but also to suppress an excessive matching process. Shape matching experiments have been successfully carried out using skeletons of totally unconstrained handwritten numerals. >
10 Jun 1994
TL;DR: Practical methods for approximate geometric pattern matching in d-dimensions and experimental data regarding the quality of matches and running times of these methods versus those of a branch-and-bound search are presented.
Abstract: We present practical methods for approximate geometric pattern matching in d-dimensions along with experimental data regarding the quality of matches and running times of these methods versus those of a branch-and-bound search. Our methods are faster than previous methods but still produce good matches.
TL;DR: In this article, a detailed and comprehensive method to establish similarities and dissimilarities in a systematic and at all stages transparent way is proposed for the analysis of the conditions of survival or breakdown of democratic systems in the inter-war period in Europe.
Abstract: Comparative political analysis at the macro-level of political systems can reduce the inevitably high complexity of such comparisons by the systematic matching or contrasting of cases, depending on the particular problem. Such 'most similar systems' or 'most different systems' designs, in Przeworski & Teune's terminology, thus constitute one of the major ways out of the usual 'small N - many variables' dilemma. This paper proposes a detailed and comprehensive method to establish such similarities and dissimilarities in a systematic and at all stages transparent way. The examples chosen refer to an analysis of the conditions of survival or breakdown of democratic systems in the inter-war period in Europe.
09 Sep 1994
TL;DR: In this paper, the efficacy of using intensity edges, curvature of iso-intensity contours, and tissue classified data for image matching is examined, and the image matching problem is formulated in such a way that the different features are handled uniformly, allowing the same code to be used in each instance.
Abstract: The efficacy of using intensity edges, curvature of iso-intensity contours, and tissue classified data for image matching are examined. The image matching problem is formulated in such a way that the different features are handled uniformly, allowing the same code to be used in each instance. The results using both simulated and real brain images indicate that each feature affected and improvement in the correspondence after matching with it.
07 Jun 1994
TL;DR: In this paper, the authors use production history to improve the estimates of geological and petrophysical parameters in the oil field and estimate response surfaces based on a set of reservoir simulations with different combinations of the reservoir parameters.
Abstract: History matching is the process of using production history to improve the estimates of geological and petrophysical parameters in the oil field. We estimate response surfaces based on a set of reservoir simulations with different combinations of the reservoir parameters. A response surface is a simplified relation y(x) between reservoir simulator input x and output (response) y, and gives a rough overview of the behavior of the response in the whole region of interest. These response surfaces are searched to find parts that are close to the historical data. Since a his tory matching problem may have several solutions, surfaces that give overview over the whole region are of interest. History matching is done by mininlizing the distance between the observed values of the response variables, and the response predicted from the response surfaces y(x). The process is iterative: make experimental design, run the selected experiments, generate response surface, optimize, make new refined design, run ... and so on. One or several iterations may be performed automatically. The method is demonstrated on a synthetic reservoir simulation example.
TL;DR: The cluster matching approach showed the best performance over a broad range of motion, illumination change and object deformation.
Abstract: A new method for estimating displacements in computer imagery through cluster matching is presented. Without reliance on any object model, the algorithm clusters two successive frames of an image sequence based on position and intensity. After clustering, displacement estimates are obtained by matching the cluster centers between the two frames using cluster features such as position, intensity, shape and average gray-scale difference. The performance of the algorithm was compared to that of a gradient method and a block matching method. The cluster matching approach showed the best performance over a broad range of motion, illumination change and object deformation. >
Book•
30 May 1994
TL;DR: The text describes and evaluates the BF, KMP, BM, and KR algorithms, discusses improvements for string pattern matching machines, and details a technique for detecting and removing the redundant operation of the AC machine.
Abstract: From the Publisher:
Introduces the basic concepts and characteristics of string pattern matching strategies and provides numerous references for further reading. The text describes and evaluates the BF, KMP, BM, and KR algorithms, discusses improvements for string pattern matching machines, and details a technique for detecting and removing the redundant operation of the AC machine. Also explored are typical problems in approximate string matching. In addition, the reader will find a description for applying string pattern matching algorithms to multidimensional matching problems, an investigation of numerous hardware-based solutions for pattern matching, and an examination of hardware approaches for full text search. The first chapter's survey paper describes the basic concepts of algorithm classifications. The five chapters that follow include 15 papers further illustrating these classifications: single keyword matching, matching sets of keywords, approximate string matching, multidimensional matching, and hardware matching.