Showing papers on "Matching (statistics) published in 1995"

Probabilistic linkage of large public health data files

Abstract: Probabilistic linkage technology makes it feasible and efficient to link large public health databases in a statistically justifiable manner. The problem addressed by the methodology is that of matching two files of individual data under conditions of uncertainty. Each field is subject to error which is measured by the probability that the field agrees given a record pair matches (called the m probability) and probabilities of chance agreement of its value states (called the u probability). Fellegi and Sunter pioneered record linkage theory. Advances in methodology include use of an EM algorithm for parameter estimation, optimization of matches by means of a linear sum assignment program, and more recently, a probability model that addresses both m and u probabilities for all value states of a field. This provides a means for obtaining greater precision from non-uniformly distributed fields, without the theoretical complications arising from frequency-based matching alone. The model includes an interative parameter estimation procedure that is more robust than pre-match estimation techniques. The methodology was originally developed and tested by the author at the U.S. Census Bureau for census undercount estimation. The more recent advances and a new generalized software system were tested and validated by linking highway crashes to Emergency Medical Service (EMS) reports and to hospital admission records for the National Highway Traffic Safety Administration (NHTSA).

Crossing network utilizing satisfaction density profile with price discovery features

Abstract: A crossing network that matches buy and sell orders based upon a satisfaction and quantity profile includes a number of trader terminals that can be used for entering orders. The orders are entered in the form of a satisfaction density profile that represents a degree of satisfaction to trade a particular instrument at various (price, quantity) combinations. Typically, each order is either a buy order or a sell order. The trader terminals are coupled to a matching controller computer. The matching controller computer can receive as input the satisfaction density profiles entered at each one of the trading terminals. The matching controller computer matches orders (as represented by each trader's satisfaction density profile) so that each trader is assured that the overall outcome of the process (in terms of average price and size of fill) has maximized the mutual satisfaction of all traders. Typically, the matching process is anonymous. The matching process can be continuous or a batch process, or a hybrid of the two. Unmatched satisfaction density profiles can be used to provide spread and pricing information. Factors other than price and quantity also may be used to determine the degree of satisfaction. Optionally, priority may be given to certain profiles in the matching process to accommodate stock exchange rules, for example, requiring that priority be given to orders exhibiting the best price, regardless of size or any other consideration.

Negotiated matching system

Abstract: A negotiated matching system includes a plurality of remote terminals associated with respective potential counterparties, a communications network for permitting communication between the remote terminals, and a matching station. Each user enters trading information and ranking information into his or her remote terminal. The matching station then uses the trading and ranking information from each user to identify transactions between counterparties that are mutually acceptable based on the ranking information, thereby matching potential counterparties to a transaction. Once a match occurs, the potential counterparties transmit negotiating messages to negotiate some or all terms of the transaction. Thus, the negotiated matching system first matches potential counterparties who are acceptable to each other based on trading and ranking information, and then enables the two counterparties to negotiate and finalize the terms of a transaction.

Crossing network utilizing optimal mutual satisfaction density profile

Abstract: A crossing network that matches buy and sell orders based upon a satisfaction and quantity profile is disclosed. The crossing network includes a number of trader terminals that can be used for entering orders. The orders are entered in the form of a satisfaction density profile that represents a degree of satisfaction to trade a particular instrument at various (price, quantity) combinations. Typically, each order is either a buy order or a sell order. The trader terminals are coupled to a matching controller computer. The matching controller computer can receive as input the satisfaction density profiles entered at each one of the trading terminals. The matching controller computer matches orders (as represented by each trader's satisfaction density profile) so that each trader is assured that the overall outcome of the process (in terms of average price and size of fill) has maximized the mutual satisfaction of all traders. Typically, the matching process is anonymous. The matching process can be continuous or performed on a batch basis.

Signature matching: a tool for using software libraries

Abstract: Signature matching is a method for organizing, navigating through, and retrieving from software libraries. We consider two kinds of software library components—functions and modules—and hence two kinds of matching—function matching and module matching. The signature of a function is simply its type; the signature of a module is a multiset of user-defined types and a multiset of function signatures. For both functions and modules, we consider not just exact match but also various flavors of relaxed match. We describe various applications of signature matching as a tool for using software libraries, inspired by the use of our implementation of a function signature matcher written in Standard ML.

Method for accessing and evaluating information for processing an application for insurance

Abstract: A method of controlling a computer network to render information needs and risk evaluative decisions includes the matching of profiles, defined by data characteristics and collective characteristics, to customer data. Multiple profiles are matched to arrive at a consensus decision, in addition to providing a rationale and summary analysis of the decision. Advice profiles provide advice, when matched, regarding customer data.

Method for rating a match for a given entity found in a list of entities

Abstract: In a system that accepts a given search entity from a user and utilizes a database to identify a possible matching entity from a large list of entries, a method is provided for evaluating the reliability of the matching entity. Preferably, the method is carried out with minimal human intervention. A user inputs a plurality of attributes to identify a given entity, the system identifies a possible matching entity, and assigns a numerical grade to reflect the match quality of each attribute. Thereafter, the method assigns a grade to each attribute score, assembles the grades into a key, uses the key to address a memory, and retrieves a confidence code or quality indicator from the memory. The confidence codes are based on empirical information and reflect the overall quality of the match for the particular entity.

Computer-based data integration and management process for workforce planning and occupational readjustment

Abstract: Disclosed is a computer system and a method for a computer-based data integration and management processing system and a method for workforce planning and occupational readjustment. The system and method of the present invention uses a number of databases that are either created internally or are imported from existing databases. These databases are manipulated by the invention for skill matching analysis based on a rigorous behavioral skill analysis of target occupations, using one or more predetermined analysis metrics and an examination of an individual's skills using metrics with similar behavioral attributes.

Fast Non-Rigid Matching of 3D Medical Images

Abstract: We present a method to perform the non-rigid matching of two 3D medical images, which is fast and fully automated. We illustrate this method in several applications, such as inter-patient registration, cardiac image sequence analysis, and the automatic registration with anatomical atlases, which we identify as currently important challenges for medical image processing. Several interesting inter-patient matching methods have been proposed recently, showing the interest of such techniques, but whose computation time is still prohibitive for practical clinical applications. The main interest of our methods is to perform a "satisfying" non-rigid matching of large image volumes within only several tens of minutes on a conventional workstation. We describe our method as based on "demons" (in the sense of Maxwell's demons) which locally deform the model to push it into a mold, as opposed to more traditional "attractor" based deformable model techniques. Finally, we present experiments on real data, and discuss two current limitations of our technique: the sensitivity to initial positioning, and to intensity variations between images.

Online tracking of mobile users

Abstract: This paper deals with the problem of maintaining a distributed directory server, that enables us to keep track of mobile users in a distributed network. The paper introduces the graph-theoretic concept of regional matching, and demonstrates how finding a regional matching with certain parameters enables efficient tracking. The communication overhead of our tracking mechanism is within a polylogarithmic factor of the lower bound.

Symbolic description and visual querying of image sequences using spatio-temporal logic

Abstract: The emergence of advanced multimedia applications is emphasizing the relevance of retrieval by contents within databases of images and image sequences. Matching the inherent visuality of the information stored in such databases, visual specification by example provides an effective and natural way to express content-oriented queries. To support this querying approach, the system must be able to interpret example scenes reproducing the contents of images and sequences to be retrieved, and to match them against the actual contents of the database. In the accomplishment of this task, to avoid a direct access to raw image data, the system must be provided with an appropriate description language supporting the representation of the contents of pictorial data. An original language for the symbolic representation of the contents of image sequences is presented. This language, referred to as spatio-temporal logic, comprises a framework for the qualitative representation of the contents of image sequences, which allows for treatment and operation of content structures at a higher level than pixels or image features. Organization and operation principles of a prototype system exploiting spatio-temporal logic to support querying by example through visual iconic interaction are expounded. >

Searching and matching unrecognized handwriting

Abstract: A method and system provide for searching and matching gesture-based data such as handwriting without performing a recognition process on the handwritten gesture data to convert it to a standard computer-coded form. Target data collected as sample data points of spatial coordinates over time are concatenated into a single target gesture sequence of sample data points. The sample data points comprising the gesture-based data structure to be searched (the corpus) are grouped into corpus gesture sequences for matching against the target gesture sequence. Matching may be done by any suitable method, and a novel signal comparison technique based on dynamic time warping concepts is illustrated. The result of the matching is a list of the locations of the matching corpus gesture sequences in the corpus, which in turn may be used for further processing, such as the display of an image of the matching corpus gestures for a system user. The ability to determine the existence and location of a gesture in the corpus that matches a target gesture is the basis for performing a variety of additional functions, such as a "find and replace" function and the ability to use gestures as keywords to index a gesture-based data structure without performing recognition on either the keyword gestures or the gesture-based data structure. The technique is suitable for inclusion in any system that accepts gesture-based data, such as a personal digital assistant (PDA) or other pen-based computing device.

Breaking the Matches in a Paired T-Test for Community Interventions When the Number of Pairs is Small

Abstract: There is considerable interest in community interventions for health promotion, where the community is the experimental unit. Because such interventions are expensive, the number of experimental units (communities) is usually small. Because of the small number of communities involved, investigators often match treatment and control communities on demographic variables before randomization to minimize the possibility of a bad split. Unfortunately, matching has been shown to decrease the power of the design when the number of pairs is small, unless the matching variable is very highly correlated with the outcome variable (in this case, with change in the health behaviour). We used computer simulation to examine the performance of an approach in which we matched communities but performed an unmatched analysis. If the appropriate matching variables are unknown, and there are fewer than ten pairs, an unmatched design and analysis has the most power. If, however, one prefers a matched design, then for N < 10, power can be increased by performing an unmatched analysis of the matched data. We also discuss a variant of this procedure, in which an unmatched analysis is performed only if the matching 'did not work'.

Prognostic Models and the Propensity Score

Abstract: Subjects in observational studies of exposure effects have not been randomized to exposure groups and may therefore differ systematically with regard to variables related to exposure and/or outcome. To obtain unbiased estimates and tests of exposure effects one needs to adjust for these variables. A common method is adjustment via a parametric model incorporating all known prognostic variables. Rosenbaum and Rubin propose adjustment by the conditional exposure probability given a set of covariates which they call the propensity score. They show that, at any value of the propensity score, covariates are on average balanced between exposure groups. Thus matching on the propensity score leads to unbiased estimators and tests of exposure effect. However, the validity of the method depends on knowing the exposure probability. This quantity is usually not known in observational studies and needs to be estimated.

Address Matching: GIS Technology for Mapping Human Activity Patterns

Abstract: Address matching is the process of adding locational information to a database containing business, survey, or administrative records. It is a very powerful GIS technology, because it can transform any existing database with street addresses into a GIS database that can be mapped or used as input into more sophisticated spatial analyses. Address matching is inexpensive, as well, since it can be performed on microcomputers with low-cost GIS software and the U.S. Census Bureau's TIGER/Line files. Although address matching has a number of important limitations, it is nevertheless one of the most cost-effective means for applying GIS mapping and spatial analysis tools to the country's pressing urban problems.

Excess Commuting in the Tokyo Metropolitan Area: Measurement and Policy Simulations

Abstract: In this paper Tokyos commuting patterns are examined to determine the extent to which the volume of commuting is an inevitable result of the functioning of such a vast interconnected economic system and the extent to which it is the result of inefficient matching of workers and jobs. Some comparisons are made to the situation in Los Angeles. Several simulations are used to examine the effect of decentralisation of employment on commuting behaviour and it is found that commuting time could be significantly reduced by decentralising jobs or centralising workers." (EXCERPT)

Adaptive block matching motion estimation algorithm using bit-plane matching

Abstract: Motion estimation/compensation techniques are extensively used in video compression because of their abilities to exploit the high temporal correlation between successive frames of an image sequence. We first propose a new matching criterion called bit-plane matching (BPM) for distance measurement in the block matching algorithm. This criterion not only considers the magnitude but also the directive information of the pixel elements in the block. A simple adaptive block matching algorithm is also developed to adjust the search origin and search range at a block-by-block basis. Simulation results show that the proposed algorithm achieves similar MSE performance for motion-predicted images but requires about 8 times less the number of computations than the full-search method.

A rigorous error analysis of D/A conversion with dynamic element matching

Abstract: A known approach to reducing harmonic distortion in D/A converters involves a technique called dynamic element matching, The idea is not to reduce the power of the overall conversion error but rather to give it a random, noise-like structure. By reducing the correlation among successive samples of the conversion error, harmonic distortion is reduced. This paper presents the first rigorous and quantitative theoretical analysis of the conversion error introduced by an important type of D/A converter with dynamic element matching, In addition to supporting previously published experimental results that indicate the conversion error consists of white noise instead of harmonic distortion, the analysis provides an expression for the power of the white noise in terms of the power of the input sequence and the component matching errors. A yield estimation technique based on the expression is presented that can be used to estimate how the power of the white noise varies across different copies of the same D/A converter circuit for any given component matching error statistics.

Matching versus cultural competence in research: Methodological considerations

Abstract: Researcher/participant matching has been used in nursing research as a strategy for the development of culturally competent knowledge. In this manuscript, the complexities inherent in matching in nursing research are discussed. In raising and discussing issues and questions related to matching, we argue that although matching may be one of the strategies used to generate culturally competent knowledge, it is frequently too complex for operationalization. Therefore, we propose that researchers reflect on questions related to their knowledge of culture, their cultural sensitivity, and the nature of collaboration during every phase of the research. Reflecting on and responding to these questions in every research project may facilitate the development of more culturally competent knowledge.

Adaptive Pattern Matching

Abstract: Pattern matching is an important operation used in many applications such as functional programming, rewriting, and rule-based expert systems. By preprocessing the patterns into a DFA-like automaton, we can rapidly select the matching pattern(s) in a single scan of the relevant portions of the input term. This automaton is typically based on left-to-right traversal of the patterns. By adapting the traversal order to suit the set of input patterns, it is possible to considerably reduce the space and matching time requirements of the automaton. The design of such adaptive automata is the focus of this paper. We first formalize the notion of an adaptive traversal. We then present several strategies for synthesizing adaptive traversal orders aimed at reducing space and matching time complexity. In the worst case, however, the space requirements can be exponential in the size of the patterns. We show this by establishing an exponential lower bounds on space that is independent of the traversal order used. We then discuss an orthogonal approach to space minimization based on direct construction of optimal dag automata. Finally, our work brings forth the impact of typing in pattern matching. In particular, we show that several important problems (e.g., lazy pattern matching in ML) are computationally hard in the presence of type disciplines, whereas they can be solved efficiently in the untyped setting.

Exact moment matching model of transmission lines and application to interconnect delay estimation

Abstract: Moment matching methods are widely used in delay estimation of interconnects modeled as transmission line networks. In this paper, we analyze the contribution of a transmission line to the moments of a resistor-transmission line-capacitor (R-T-C) network and provide a method to form a lumped moment matching model of the line. When the transmission lines are replaced by their pth order moment matching models, the network is transformed into a lumped R-L-C network such that these two networks have identical moments up to the order of p for each corresponding output node voltage. We also provide a recursive formula to compute the moments of the R-L-C network so that the moment matching techniques can be efficiently used in the delay estimation. >

Probabilistic Matching of Brain Images

Abstract: Image matching has emerged as an important area of investiga tion in medical image analysis In particular much attention has been fo cused on the atlas problem in which a template representing the structural anatomy of the human brain is deformed to match anatomic brain images from a given individual The problem is made di cult because there are important di erences in both the gross and local morphology of the brain among normal individuals We have formulated the image matching prob lem under a Bayesian framework The Bayesian methodology facilitates a principled approach to the development of a matching model Of special in terest is its capacity to deal with uncertainty in the estimates a potentially important but generally ignored aspect of the solution In the construction of a reference system for the human brain the Bayesian approach is well suited to the task of modeling variation in morphology Statistical informa tion about morphological variability accumulated over past samples can be formally introduced into the problem formulation to guide the matching or normalization of future data sets To appear in Proceedings of XIVth International Conference on Information Pro cessing in Medical Imaging Ile de Berder France June

Modal matching: a method for describing, comparing, and manipulating digital signals

Abstract: Thesis (Ph. D.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1995.

Pattern matching for design concept localization

Abstract: The effective synergy of a number of different techniques is the key to the successful development of an efficient reverse engineering environment. Compiler technology, pattern matching techniques, visualization tools, and software repositories play an important role for the identification of procedural, data, and abstract-data-type related concepts in the source code. This paper describes a number of techniques used for the development of a distributed reverse engineering environments. Design recovery is investigated through code-to-code and abstract-descriptions-to-code pattern matching techniques used to locate code that may implement a particular plan or algorithm. The code-to-code matching uses dynamic programming techniques to locate similar code fragments and is targeted for large software systems (1MLOC). Patterns are specified either as source code or as a sequence of abstract statements written in an concept language developed for this purpose. Markov models are used to compute similarity measures between an abstract description and or code fragment in terms of the probability that a given abstract statement can generate a given code fragment. The abstract-description-to-code matcher is under implementation and early experiments show it is a promising technique.