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At least 217 records · Page 12Linked to original sources
PubMed2001

SignStream: a tool for linguistic and computer vision research on visual-gestural language data.

Research on recognition and generation of signed languages and the gestural component of spoken languages has been held back by the unavailability of large-scale linguistically annotated corpora of the kind that led to significant advances in the area of spoken language. A major obstacle has been the lack of computational tools to assist in efficient analysis and transcription of visual language data. Here we describe SignStream, a computer program that we have designed to facilitate transcription and linguistic analysis of visual language. Machine vision methods to assist linguists in detailed annotation of gestures of the head, face, hands, and body are being developed. We have been using SignStream to analyze data from native signers of American Sign Language (ASL) collected in our new video collection facility, equipped with multiple synchronized digital video cameras. The video data and associated linguistic annotations are being made publicly available in multiple formats.

Computer Simulation↗
PubMed2003

Support vector machine applications in bioinformatics.

The support vector machine (SVM) approach represents a data-driven method for solving classification tasks. It has been shown to produce lower prediction error compared to classifiers based on other methods like artificial neural networks, especially when large numbers of features are considered for sample description. In this review, the theory and main principles of the SVM approach are outlined, and successful applications in traditional areas of bioinformatics research are described. Current developments in techniques related to the SVM approach are reviewed which might become relevant for future functional genomics and chemogenomics projects. In a comparative study, we developed neural network and SVM models to identify small organic molecules that potentially modulate the function of G-protein coupled receptors. The SVM system was able to correctly classify approximately 90% of the compounds in a cross-validation study yielding a Matthews correlation coefficient of 0.78. This classifier can be used for fast filtering of compound libraries in virtual screening applications.

Algorithms↗
PubMed1998

The impact of a computer generated patient held health record.

OBJECTIVE: To examine the use and impact of a computer generated, patient held health record (PHR) on information sharing, responsibility sharing and preventive health care. SETTING: An academic group, private solo and private group general practice in Adelaide, South Australia. METHODS: Patients with chronic health problem(s) were randomly assigned to an experimental control or post test only group. Pre and post intervention data were collected using a standardised audit and abstraction of the patient records into a computer based record system. In addition, patient and doctor questionnaires, telephone follow ups and face to face interviews were conducted. OUTCOME MEASURES: Patient and GP use of, and satisfaction with the PHR; effectiveness of information and responsibility sharing; and uptake and performance of selected preventive health care by patient and GP. RESULTS: Seventy-two patients were recruited (29 received the PHR, and 22 each were in the control and post test only groups). The PHR was well received and used in both primary and secondary care settings. No statistically significant differences in the outcome measures were found between the groups as well as before and after the intervention (Kruskal-Wallis, p > 0.05). Data trends suggested that the PHR may increase information and responsibility sharing as well as improve patient awareness of the issues involved, with patient participation in information sharing, preventive health care and clinical decision making. Provided training and resources were made available, participating GPs believed that the computer based methodology developed was a practical option for use in practice. CONCLUSION: The computer generated PHR is an important determinant of patient participation in information and responsibility sharing, health promotion, and disease management. Implementation and evaluation studies are recommended.

Adolescent↗
PubMed1998

Concepts, knowledge and language in healthcare information systems: follow-up 30 months later.

The paper reviews the last IMIA-WG6 recommendations, issued along two themes: (1) how to better share common results and (2) how to conduct new research and development efforts. Some of the major discrepancies in the field are reviewed. The paper intends to offer insight into two areas, first, in the issue of knowledge representation and, second, in the science of meaning, incorporating the broad intersection of computational linguistics, semantics, conceptual approach, and denotation. The Ogden-Richards meaning triangle is used as a convenient organizing principle to maximize the scope of understanding among the different schools, particularly in areas of linguistics and semantics on the one side and denotation and conceptual approach on the other. In conclusion, there is a need for clarification and for more scientific pragmatism.

Artificial Intelligence↗
PubMedDate not supplied

[Method of computing the geometrical parameters of contact lenses].

Contact lenses of home-made production are classified, and the methodology of computing their structural elements for several types of lenses is presented. Some design features of the parameters are considered with regard to the properties of the water-receptive material used for soft lenses.

Contact Lenses↗
PubMedDate not supplied

An integrated methodological approach to the computer-assisted gas chromatographic screening of basic drugs in biological fluids using nitrogen selective detection.

This paper presents the methodological aspects of a computerized system for the gas-chromatographic screening and primary identification of central nervous system stimulants and narcotic analgesics (including some of their respective metabolites) extracted from urine. The operating conditions of a selective nitrogen detector for optimized analytical functions are discussed, particularly the effect of carrier and fuel gas on the detector's sensitivity to nitrogen-containing molecules and discriminating performance toward biological matrix interferences. Application of simple extraction techniques, combined with rapid derivatization procedures, computer data acquisition, and reduction of chromatographic data are presented. Results show that this system approach allows for the screening of several drugs and their metabolites in a short amount of time. The reliability and stability of the system have been tested by analyzing several thousand samples for doping control at major international sporting events and for monitoring drug intake in addicts participating in a rehabilitation program. Results indicate that these techniques can be used and adapted to many different analytical toxicology situations.

Body Fluids↗
PubMedDate not supplied

[Structural principles in the creation of training in medical information retrieval systems].

The systems approach has been used to consider the principles in the creation of the popular medical information retrieval systems (IRSs) BodyWorks, 3DBody, MAYO Clinic on IBM personal computers. The methodological problems in the use of IRSs in a training process, requirements for computer resources, strategy for development of such systems under the Russian conditions are discussed in the paper. Guidelines for further developments are also forwarded.

Information Systems↗
PubMed1997

Two complementary methods for predicting peptides binding major histocompatibility complex molecules.

Peptides that bind to major histocompatibility complex products (MHC) are known to exhibit certain sequence motifs which, though common, are neither necessary nor sufficient for binding: MHCs bind certain peptides that do not have the characteristic motifs and only about 30% of the peptides having the required motif, bind. In order to develop and test more accurate methods we measured the binding affinity of 463 nonamer peptides to HLA-A2.1. We describe two methods for predicting whether a given peptide will bind to an MHC and apply them to these peptides. One method is based on simulating a neural network and another, called the polynomial method, is based on statistical parameter estimation assuming independent binding of the side-chains of residues. We compare these methods with each other and with standard motif-based methods. The two methods are complementary, and both are superior to sequence motifs. The neural net is superior to simple motif searches in eliminating false positives. Its behavior can be coarsely tuned to the strength of binding desired and it is extendable in a straightforward fashion to other alleles. The polynomial method, on the other hand, has high sensitivity and is a superior method for eliminating false negatives. We discuss the validity of the independent binding assumption in such predictions.

Artificial Intelligence↗
PubMed1984

Analyzing and comparing the performance of two real-time playback systems.

A technique used in animated computer graphics involves the use of real-time playback. This method is used when it is not possible to display frames of display code in real-time. Instead, frames are compiled in advance at non realtime rates, saved in secondary storage, and played back at desired realtime speeds. The basic design and operation of two such systems will be considered. The more powerful of the two is built upon an Evans and Sutherland picture System I and utilizes animated vector graphics. The other playback system is built upon a Terak micro computer display and represents an example of rudimentary raster graphics animation. The synchronization, buffering, blocking and man-machine interfaces of both systems are detailed thus spotlighting their operational behavior. A comparison of the two systems show: that similarities in the logical organization of each system exist; that both systems are input bound; and both require their image files to be built on other computer systems. The differences in the performance of the two systems can be attributed to technological differences between the two systems; the retrieval rates of their respective disk subsystems; and differences in the intent and purpose behind the design of each machine. The systems are demonstrated by applying them to chemical modeling. It is determined that playback is a useful technique for examining complicated sequential situations or for providing the concise and convenient representation of large amounts of data.

Computer Graphics↗
PubMedDate not supplied

Parallel computation of simple arithmetic using peptide-antibody interactions.

We propose a theoretical model for representing and manipulating binary numbers using peptide-antibody interactions. In particular, we present models to solve simple binary arithmetical problems like addition and subtraction. As the interactions can take place in parallel we show that the number of steps is independent of the size (bits) of the numbers.

Algorithms↗
PubMed1997

World Wide Web interface for advanced SPECT reconstruction algorithms implemented on a remote massively parallel computer.

Data from Single Photon Emission Computed Tomography (SPECT) studies are blurred by inevitable physical phenomena occurring during data acquisition. These errors may be compensated by means of reconstruction algorithms which take into account accurate physical models of the data acquisition procedure. Unfortunately, this approach involves high memory requirements as well as a high computational burden which cannot be afforded by the computer systems of SPECT acquisition devices. In this work the possibility of accessing High Performance Computing and Networking (HPCN) resources through a World Wide Web interface for the advanced reconstruction of SPECT data in a clinical environment was investigated. An iterative algorithm with an accurate model of the variable system response was ported on the Multiple Instruction Multiple Data (MIMD) parallel architecture of a Cray T3D massively parallel computer. The system was accessible even from low cost PC-based workstations through standard TCP/IP networking. A speedup factor of 148 was predicted by the benchmarks run on the Cray T3D. A complete brain study of 30 (64 x 64) slices was reconstructed from a set of 90 (64 x 64) projections with ten iterations of the conjugate gradients algorithm in 9 s which corresponds to an actual speed-up factor of 135. The technique was extended to a more accurate 3D modeling of the system response for a true 3D reconstruction of SPECT data; the reconstruction time of the same data set with this more accurate model was 5 min. This work demonstrates the possibility of exploiting remote HPCN resources from hospital sites by means of low cost workstations using standard communication protocols and an user-friendly WWW interface without particular problems for routine use.

Algorithms↗
PubMed1998

Integration of a blood pressure controller and an infusion toolbox system using client-server technology.

This paper shortly describes an Infusion Toolbox and a blood pressure (BP) control application. It explains how we applied an agent model and client-server technology to integrate them. We show that by using this framework and object oriented technologies the necessary changes to the existing applications are reduced. Many elements of the tested original systems could be re-used, which enhances safe development.

Anesthesia↗
PubMed2004

How much information can one store in a nonequilibrium medium?

It has recently been emphasized again that the very existence of stationary stable localized structures with short-range interactions might allow one to store information in nonequilibrium media, opening new perspectives on information storage. We show how to use generalized topological entropies to measure aspects of the quantities of storable and nonstorable information. This leads us to introduce a measure of the long-term stably storable information. As a first example to illustrate these concepts, we revisit a mechanism for the appearance of stationary stable localized structures that is related to the stabilization of fronts between structured and unstructured states (or between differently structured states).

Computers, Molecular↗
PubMed1999

Developments in component-based normalization for 3D PET.

Normalization in positron emission tomography (PET) is the process of ensuring that all lines of response joining detectors in coincidence have the same effective sensitivity. In three-dimensional (3D) PET, normalization is complicated by the presence of a large proportion of scattered coincidences, and by the fact that cameras operating in 3D mode encounter a very wide range of count-rates. In this work a component-based normalization model is presented which separates the normalization of true and scattered coincidences and accounts for variations in normalization effects with count-rate. The effects of the individual components in the model on reconstructed images are investigated, and it is shown that only a subset of these components has a significant effect on reconstructed image quality.

Adult↗
PubMed1997

EEG data compression techniques.

In this paper, electroencephalograph (EEG) and Holter EEG data compression techniques which allow perfect reconstruction of the recorded waveform from the compressed one are presented and discussed. Data compression permits one to achieve significant reduction in the space required to store signals and in transmission time. The Huffman coding technique in conjunction with derivative computation reaches high compression ratios (on average 49% on Holter and 58% on EEG signals) with low computational complexity. By exploiting this result a simple and fast encoder/decoder scheme capable of real-time performance on a PC was implemented. This simple technique is compared with other predictive transformations, vector quantization, discrete cosine transform (DCT), and repetition count compression methods. Finally, it is shown that the adoption of a collapsed Huffman tree for the encoding/decoding operations allows one to choose the maximum codeword length without significantly affecting the compression ratio. Therefore, low cost commercial microcontrollers and storage devices can be effectively used to store long Holter EEG's in a compressed format.

Algorithms↗
PubMed2002

Automatic "pipeline" analysis of 3-D MRI data for clinical trials: application to multiple sclerosis.

The quantitative analysis of magnetic resonance imaging (MRI) data has become increasingly important in both research and clinical studies aiming at human brain development, function, and pathology. Inevitably, the role of quantitative image analysis in the evaluation of drug therapy will increase, driven in part by requirements imposed by regulatory agencies. However, the prohibitive length of time involved and the significant intraand inter-rater variability of the measurements obtained from manual analysis of large MRI databases represent major obstacles to the wider application of quantitative MRI analysis. We have developed a fully automatic "pipeline" image analysis framework and have successfully applied it to a number of large-scale, multicenter studies (more than 1,000 MRI scans). This pipeline system is based on robust image processing algorithms, executed in a parallel, distributed fashion. This paper describes the application of this system to the automatic quantification of multiple sclerosis lesion load in MRI, in the context of a phase III clinical trial. The pipeline results were evaluated through an extensive validation study, revealing that the obtained lesion measurements are statistically indistinguishable from those obtained by trained human observers. Given that intra- and inter-rater measurement variability is eliminated by automatic analysis, this system enhances the ability to detect small treatment effects not readily detectable through conventional analysis techniques. While useful for clinical trial analysis in multiple sclerosis, this system holds widespread potential for applications in other neurological disorders, as well as for the study of neurobiology in general.

Algorithms↗