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Results for “process mapping”

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At least 55 records · Page 3Linked to original sources
PubMed1990

Self-organization of associative memory and pattern classification: recurrent signal processing on topological feature maps.

We extend the neural concepts of topological feature maps towards self-organization of auto-associative memory and hierarchical pattern classification. As is well-known, topological maps for statistical data sets store information on the associated probability densities. To extract that information we introduce a recurrent dynamics of signal processing. We show that the dynamics converts a topological map into an auto-associative memory for real-valued feature vectors which is capable to perform a cluster analysis. The neural network scheme thus developed represents a generalization of non-linear matrix-type associative memories. The results naturally lead to the concept of a feature atlas and an associated scheme of self-organized, hierarchical pattern classification.

Algorithms↗
PubMed1988

Probability mapping: power and coherence analyses of cognitive processes.

In recent years different mapping techniques have proved to be an efficient means in studying cognitive processes. Our approach is based on recordings with 19 EEG channels and the computation of spectral parameters. Power and coherence values are obtained from the EEG of control recordings and recordings during the performance of cognitive tasks and are compared for significant differences. The statistical procedures used yield descriptive error probabilities for the rejection of the null hypothesis which are mapped either colour coded or by black and white squares. The usefulness of this method is demonstrated on a mental cube rotation study involving 31 students, 13 males and 18 females. One essential result during the performance of this test is an increase of theta power only in females. As far as local coherence and the theta band are concerned, males show increased values right parietally and right temporo-occipitally; opposed to this, in females the left hemisphere is more affected. In the beta bands, local coherence increases in males right parietally and left temporo-occipitally. Contrary to this, in females the parietal increase of local coherence is more accentuated in the left hemisphere but temporo- occipital coherence is increased in the right hemisphere. In both sexes interhemispheric parietal coherence increases during cube rotation suggesting increased functional couplings between the hemispheres. This study demonstrates that the inclusion of the coherence parameter in brain mapping furthers the detection of sex and hemispheric differences during the performance of cognitive tasks.

Adult↗
PubMedDate not supplied

Data representation for subsequent image interpretation.

Radiological scans acquired using either the X-ray CT or the NMR imaging techniques provide a wealth of information about tissue behaviour under that imaging modality and contrast agent. To reason about the image in an interpretation stage the scans have to be converted from a pixel by pixel representation to a symbolic form. The technique used by us to generate such a description is region-based segmentation. Each region refers to a pixel or group of pixels having a common attribute. This work has provided a quantitative measure for the partial evaluation of the segmentation which can be applied independent of attribute or combination of attributes. From our initial studies of the behaviour of CT scans a precept for segmentation was developed. The segmentation employs a one-to-one map as an adaptive mechanism. The segmentation criterion at each point in the image therefore depends on the value at the corresponding point in the map. Any process can be used to generate this map, and so easily utilizes new operators as they are developed.

Artificial Intelligence↗
PubMed1988

Mapping techniques for document processing.

An information retrieval system should provide references to the set of documents the user must evaluate in order to satisfy his/her information requirements. A major concern in this evaluation process is whether or not a document meets the user's needs. In many document retrieval systems there is no relevant information regarding the content of the documents. This makes it very difficult to evaluate if a document is relevant to the user's initial query. This suggests the need for a method to compare the documents on a word by word basis. Fully automated methods are too complex and difficult to generalize upon. A semiautomated user driven method for document mapping is described in this paper. It should decrease the amount of time required to validate the information content of a query.

Documentation↗
PubMed1995

Fragment collapsing and splitting while assembling high-resolution restriction maps.

In the process of constructing high-resolution restriction maps via greedy algorithms, a classical anomaly, known as fragment collapsing, introduces errors into the maps that impedes further map assembly. Fragment collapsing occurs when two different genomic fragments of approximately the same length and occurring in the digestion of two different overlapping clones are incorrectly identified as representative of a single genomic fragment. This introduces a single fragment of commensurate length into an incorrect position in the map. The present work describes techniques for detecting and correcting such anomalies.

Algorithms↗
PubMed1990

Crystalluria, medullary matrix crystal deposits and bladder calculi associated with an acutely induced renal papillary necrosis.

A single (100 mg/kg) intraperitoneal dose of 2-bromoethanamine hydrobromide induced renal papillary necrosis (RPN) acutely in rodents and caused a transient crystalluria between 4 and 8 h after dosing. These crystals comprised struvite or magnesium ammonium phosphate (MAP) as assessed by shape, solubility, infra-red spectrum and X-ray microprobe analysis. Acid-soluble, bi-refringent crystals were also present within the renal medullary matrix during the same time period as the crystalluria. The presence of the MAP was associated with loss of the anionic renal medullary mucopolysaccharides staining. A total of 5/64 rats with a 2-bromoethanamine-induced renal papillary necrosis and monitored for up to 160 days had bladder calculi that were predominantly MAP. These data suggest that medullary mucopolysaccharide matrix disruption associated with RPN leads to a release of previously bound cations, super-saturation and the nucleation of crystalline MAP. These processes could also be implicated in the formation of MAP bladder calculi.

Animals↗
PubMed1988

Spectral processing for parallel recording of elemental maps.

Seven different one-, two-, or three-parameter analytic expressions were tested for their applicability to electron energy-loss spectral processing for mapping of atomic distributions in images of magnesium oxide crystals. Two-point two-parameter fits all provided indistinguishable results. Fine structure in the spectrum produced major quantitative inconsistencies for any given expression. This effect was exacerbated with the use of three-parameter expressions. Mass-thickness effects on the oxygen map of Mg0 were inconsequential up to a crystal thickness of 30 nm, but became dominant and unacceptable at a 50% increase in thickness above this. This observation can be explained by a specific single inelastic scatter coupled with any number of elastic scattering events.

Crystallization↗
PubMed1991

Mathematical problem solving by analogy.

We report the results of 2 experiments and a verbal protocol study examining the component processes of solving mathematical word problems by analogy. College students first studied a problem and its solution, which provided a potential source for analogical transfer. Then they attempted to solve several analogous problems. For some problems, subjects received one of a variety of hints designed to reduce or eliminate the difficulty of some of the major processes hypothesized to be involved in analogical transfer. Our studies yielded 4 major findings. First, the process of mapping the features of the source and target problems and the process of adapting the source solution procedure for use in solving the target problem were clearly distinguished: (a) Successful mapping was found to be insufficient for successful transfer and (b) adaptation was found to be a major source of transfer difficulty. Second, we obtained direct evidence that schema induction is a natural consequence of analogical transfer. The schema was found to co-exist with the problems from which it was induced, and both the schema and the individual problems facilitated later transfer. Third, for our multiple-solution problems, the relation between analogical transfer and solution accuracy was mediated by the degree of time pressure exerted for the test problems. Finally, mathematical expertise was a significant predictor of analogical transfer, but general analogical reasoning ability was not. The implications of the results for models of analogical transfer and for instruction were considered.

Adult↗
PubMed2026

Mapping the de-implementation of traditional diagnostic tests in pediatric acute lymphoblastic leukemia.

INTRODUCTION: Advances in cancer diagnostics raise questions about when and how to de-implement traditional approaches; however, these processes remain poorly described. At St. Jude Children's Research Hospital (SJCRH), routine conventional cytogenetics for pediatric acute lymphoblastic leukemia (ALL) diagnosis was de-implemented in 2018 following adoption of clinical genomics. This study aimed to map this process to inform future diagnostic de-implementation initiatives. METHODS: Interviews were conducted with SJCRH staff involved or impacted by cytogenetics de-implementation. Data were analyzed using thematic and rapid qualitative analysis informed by the Consolidated Framework for Implementation Research. Member-checking was used to verify and refine process maps, which were subsequently reviewed by an external expert panel, representing diverse settings, through focus group discussions. RESULTS: Thirteen SJCRH clinicians participated. De-implementation was described as successful, with no negative impact on patient outcomes. Decision-making began with internal correlation studies that demonstrated superior diagnostic performance of clinical genomics. De-implementation was viewed as a natural evolution that improved molecular classification, resource allocation, and workflow efficiency. Perceived risks included loss of cytogenetics competency, delayed turnaround time, and career insecurity, all addressed institutionally. Lessons learned highlighted the importance of deliberate discussion about logic and evidence supporting de-implementation. Fifteen external experts offered suggestions to improve process map generalizability, highlighting institutional- and system-level considerations. CONCLUSION: De-implementation of cytogenetics in ALL in favor of clinical genomics was successful at SJCRH. This study offers an example of diagnostic de-implementation in cancer care and proposes a structured approach to guide future efforts. De-implementation should be considered alongside introduction of novel diagnostic approaches.

cancer diagnostics↗
PubMed1992

Classification of pathologies by reduced sequential potential maps.

Body surface potential mapping (BSPM) is an electrocardiographic measuring technique which produces the data as a series of three-dimensional maps. These maps are assumed to contain information which may help classify subjects for diagnostic purposes more effectively than standard ECGs. As quantitative classification of the complete sequences of maps is complex and cumbersome, the present study uses extracted features which characterise the data. The features, which have been presented and evaluated in a recent work, have been extracted after the maps were processed by a compression technique which conserved the spatial details of the maps. The compression by two-level thresholding converted the sequences of maps into sequences of annuli, from which the following features were extracted: time indices, velocity vector magnitude, loci in three-dimensional space of the centres of mass and cross-correlation coefficients between successive annuli in the sequence. Here, three different classification methods are applied to these features: statistical methods, the Fisher linear discriminant method and visual inspection. BSPMs from 54 subjects are used: 25 normal, 11 WPW syndrome and 18 CAD cases. It is found that by applying a decision role which comprises all features, the procedure offers a completely accurate classification of the subjects to their groups. The three-dimensional centre of mass is found to be the single best classifier; successfully categorising 20/25 of the normals 17/18 of the CAD patients and 11/11 of the WPW patients.

Action Potentials↗
PubMed1986

[Methodology, limitations and value of mapping in electroencephalography].

Data processing is mandatory for EEG mapping. After having used a correct filter and ADC, spectral analysis is completed by interpolating between the spectral values obtained on each recording point to allow a sufficient number of values to be expressed in a grey or color scale on the skull projection plane. The obtention of valid results implies extreme care in data recording and processing. Transitory events (paroxysmal bursts) cannot be detected by spectral analysis. Nevertheless, EEG spectral data mapping is a very good technique to show abnormal EEG focuses in neurology, to study all sorts of neuropsychological reactivities, to follow the evolution of tracings during normal or abnormal aging, metabolic diseases or drug effects.

Aging↗
PubMed1989

Grouping processes in visual search: effects with single- and combined-feature targets.

We report evidence for spatially parallel visual search for targets defined by combinations of form elements in visual search. In Section 1, we show that flat search functions occur for combined-form targets when distractor forms are homogeneous and can be grouped together, thus segmenting the target from the distractors. Introducing heterogeneous distractors lessens distractor grouping and can produce serial search. These results cannot be easily attributed to subjects' use of local feature information to discriminate targets. Instead, they suggest that grouping can operate at a level at which combined form information is represented. In Section 2 we show that these grouping effects are spatially scaled by the size of the stimuli. In Section 3 we show that heterogeneity does not prevent flat search functions when the target has a unique defining feature. The data are interpreted in terms of a hierarchical processing system involving both devoted single-feature and combined-feature (junction) maps. Grouping processes can operate at both the single-feature and the combined-form levels. Selection in visual search remains confined to one object description at a time, but this description can be at various spatial scales, including that at the level of grouped forms.

Attention↗
PubMed1990

Spectrotemporal analysis of ventricular late potentials.

The authors introduce a new technique for the analysis of ventricular late potentials: spectrotemporal mapping. Spectrotemporal mapping displays a signal in both the time and frequency domains simultaneously, overcoming some of the limitations of single domain analysis. Spectrotemporal analysis of late potentials was developed from a critique of classical spectral analysis methods. Several examples of spectrotemporal analysis of signal-averaged ECG waveforms are presented. These include cases in which spectrotemporal mapping was able to represent late potentials that were not seen after conventional time-domain processing. Spectrotemporal mapping reveals that ventricular late potentials have a time-varying energy spectrum, which theoretically would preclude the use of classical Fourier analysis techniques. Both the vector magnitude and Fourier transformations are a reduced representation of the information available in the signal average. Spectrotemporal mapping combines time and frequency information in a way that is compatible with the basic statistical structure of late potentials.

Electrocardiography↗
PubMed1990

A genetic map of human chromosome 17p.

A genetic linkage map was constructed with 18 loci from the short arm and pericentric region of chromosome 17 typed on the CEPH reference families. The genetic map includes three markers extracted from the CEPH public database. Nine loci could be ordered using a threshold of odds of at least 1000:1 against alternative orders during the map construction process. With a reduced tolerance of 100:1, a total of 13 loci could be placed on the map spanning a distance of approximately 60 cM in females and 46 cM in males. There were statistically significant differences between the male and the female genetic maps. The order inferred from the genetic data was consistent with the physical localizations of these probes obtained from somatic cell hybrids and tumor deletion studies. This map should be useful for genetic fine mapping of 17p loci.

Alleles↗
PubMed1991

Processing and termination of 23S rRNA-5S rRNA-tRNA(Gly) primary transcripts in Thermus thermophilus HB8.

The two 23S rRNA-5S rRNA-tRNAGly operons from the extreme thermophilic eubacterium Thermus thermophilus HB8 were used to characterized the in vivo processing and termination of 23S rRNA-5S rRNA-tRNAGly primary transcripts in this organism by nuclease S1 mapping. A processing site in the pre-23S rRNA 3'-flanking region is located approximately 25 nucleotides upstream of 5S rRNA and precedes a putative 23S-5S rRNA spacer antitermination box A. Cleavage at this site and 5S rRNA 5' end formation were shown to be inseparable events. Termination of transcription at the uridine cluster following the termination-associated hairpin was shown to be efficient but leaky. Subsequent to the operon, a functional promoter was detected whose -35 box coincided with the uridine-rich termination region. The promoter directed synthesis of a beta-galactosidase fusion protein in Escherichia coli.

Base Sequence↗
PubMed1988

Proprioceptors and their contribution to somatosensory mapping: complex messages require complex processing.

This review of other people's work concentrates on two matters. First, which of the various receptors are chiefly involved in creating the central representations or maps of the body that both underlie the conscious perception of our body image and are needed to control our motor performance. Second, how are these relatively well-charted signals used in sensorimotor mapping, with particular attention paid to various human psychophysical observations and illusions that throw light on the central integrative mechanisms involved. Detailed citation is largely restricted to developments since earlier reviews.

Animals↗