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At least 757 records · Page 42Linked to original sources
PubMed2003

Hot spot detection based on feature space representation of visual search.

This paper presents a new framework for capturing intrinsic visual search behavior of different observers in image understanding by analysing saccadic eye movements in feature space. The method is based on the information theory for identifying salient image features based on which visual search is performed. We demonstrate how to obtain feature space fixation density functions that are normalized to the image content along the scan paths. This allows a reliable identification of salient image features that can be mapped back to spatial space for highlighting regions of interest and attention selection. A two-color conjunction search experiment has been implemented to illustrate the theoretical framework of the proposed method including feature selection, hot spot detection, and back-projection. The practical value of the method is demonstrated with computed tomography image of centrilobular emphysema, and we discuss how the proposed framework can be used as a basis for decision support in medical image understanding.

Adult↗
PubMedDate not supplied

A conceptual framework for managing clinical processes.

Reengineering of the health care delivery system is underway, as is the transformation of the processes and methods used for recording information describing patient care (i.e., the development of a computer-based record). This report describes the use of object-oriented analysis and design to develop and implement clinical process reengineering as well as the organization of clinical data. In addition, the facility of the proposed framework for implementing workflow computing is discussed.

Ambulatory Care↗
PubMed1989

Developing the request for proposal.

A well thought-out RFP can serve a variety of purposes in the selection of a pharmacy computer vendor system, including a planning document, a means of communication, a framework for vendor selection, and a lever for postinstallation vendor accountability. Considering the magnitude of the investment, the importance of a viable computer system to the overall departmental operation, and the potential impact of a poor decision choice, the RFP is well worth the investment of time, energy, and thought required.

Communication↗
PubMed2026

AI-genomics synergy for drug repurposing in breast cancer: an interpretability-driven framework.

Breast cancer's genomic heterogeneity complicates drug discovery, making repurposing an attractive but challenging strategy. Advances in artificial intelligence now enable integration of multi-omics data to reveal drug-gene-disease relationships and generate subtype-specific repurposing hypotheses. In this Review, we examine AI-driven computational approaches from signature-based to multi-modal frameworks and propose an integrated interpretability-driven framework linking mechanistic validation with clinical translation toward more transparent and actionable precision oncology.

Journal Article↗
PubMed2005

Muscle blood flow-O2 uptake interaction and their relation to on-exercise dynamics of O2 exchange.

A computer model was developed to provide a theoretical framework for interpreting the dynamics of muscle capillary O(2) exchange in health and disease. We examined the effects of different muscle oxygen uptake (V O(2m)) and CvO(2) profiles on muscle blood flow (Q (m)) kinetics (Q (m)=V O(2m)/[CaO(2)-CvO(2)]). Further, we simulated V O(2m) and Q (m) responses to predict the CvO(2) profile and the underlying dynamics of capillary O(2) exchange (CvO(2)=CaO(2)-V O(2m)/Q (m)). Exponential equations describing V O(2m), CvO(2) and Q (m) responses in vivo were used in the simulations. The results indicated that Q (m) kinetics were relatively insensitive to CvO(2) parameters, but directly associated with V O(2m) kinetics. The biphasic Q (m) response produced a substantial fall in CvO(2) within the first 15-20s of the exercise transition (phase 1 of Q (m)). These results revealed that the main determinant of CvO(2) (or O(2) extraction) kinetics was the dynamic interaction of Q (m) and V O(2m) kinetics during phase 1 of Q (m).

Capillaries↗
PubMedDate not supplied

Technology assessment. A framework for generating questions useful in evaluating nursing information systems.

Nursing information systems are computer systems that enable nurses to collect, manipulate, store, retrieve, display, and communicate data to administer nursing services and resources, manage nursing practice to improve patient care, and advance nursing knowledge. Selection and implementation of a nursing information system require a clear vision of the need for the system, careful planning, and astute forward thinking. Technology assessment provides a framework for generating pragmatic questions that can be used in systematically evaluating nursing information systems. This article provides a brief overview of nursing information systems, explains the technology assessment framework, and gives examples of questions useful in evaluating a nursing information system.

Computer Security↗
PubMed2007

The basal ganglia and cortex implement optimal decision making between alternative actions.

Neurophysiological studies have identified a number of brain regions critically involved in solving the problem of action selection or decision making. In the case of highly practiced tasks, these regions include cortical areas hypothesized to integrate evidence supporting alternative actions and the basal ganglia, hypothesized to act as a central switch in gating behavioral requests. However, despite our relatively detailed knowledge of basal ganglia biology and its connectivity with the cortex and numerical simulation studies demonstrating selective function, no formal theoretical framework exists that supplies an algorithmic description of these circuits. This article shows how many aspects of the anatomy and physiology of the circuit involving the cortex and basal ganglia are exactly those required to implement the computation defined by an asymptotically optimal statistical test for decision making: the multihypothesis sequential probability ratio test (MSPRT). The resulting model of basal ganglia provides a new framework for understanding the computation in the basal ganglia during decision making in highly practiced tasks. The predictions of the theory concerning the properties of particular neuronal populations are validated in existing experimental data. Further, we show that this neurobiologically grounded implementation of MSPRT outperforms other candidates for neural decision making, that it is structurally and parametrically robust, and that it can accommodate cortical mechanisms for decision making in a way that complements those in basal ganglia.

Algorithms↗
PubMed2006

Integrating modelling and experiments to assess dynamic musculoskeletal function in humans.

Magnetic resonance imaging, bi-plane X-ray fluoroscopy and biomechanical modelling are enabling technologies for the non-invasive evaluation of muscle, ligament and joint function during dynamic activity. This paper reviews these various technologies in the context of their application to the study of human movement. We describe how three-dimensional, subject-specific computer models of the muscles, ligaments, cartilage and bones can be developed from high-resolution magnetic resonance images; how X-ray fluoroscopy can be used to measure the relative movements of the bones at a joint in three dimensions with submillimetre accuracy; how complex 3-D dynamic simulations of movement can be performed using new computational methods based on non-linear control theory; and how musculoskeletal forces derived from such simulations can be used as inputs to elaborate finite-element models of a joint to calculate contact stress distributions on a subject-specific basis. A hierarchical modelling approach is highlighted that links rigid-body models of limb segments with detailed finite-element models of the joints. A framework is proposed that integrates subject-specific musculoskeletal computer models with highly accurate in vivo experimental data.

Animals↗
PubMed1997

Some organizing principles for the control of movement based on olivocerebellar physiology.

Motor control is defined as the process of restricting the output of the motor nervous system so that meaningful and coordinated behavior ensues. The high dimensionality of the computation underlying motor control is presented and a simplifying framework is outlined. Evidence that movements are performed non-continuously is reviewed as is the construct of the 'motor synergy' as a fundamental unit of control. It is proposed that the pulsatile nature of movement and the tendency of muscle collectives to be activated as synergies reflect processes that the nervous system has evolved to reduce the dimensionality of motor control. We propose that the inferior olive simplifies the computation underlying motor control by biasing the activities of spinal and cranial motor systems so that discrete collectives of muscles are predisposed to contract at specific times during movement. The well-characterized oscillatory activity of olivary neurons is postulated to provide a pacemaking signal and to restrict the control process to particular moments in time while the process of electrotonic coupling and uncoupling of assemblies of olivary neurons is proposed to underlie the spatial distribution of synergic muscle activations. It is proposed that the olivocerebellar contribution to the control process is to allow movements to be executed rapidly in a feedforward manner, so that the need for sensory guidance and feedback is minimized.

Animals↗
PubMed2001

Effects of computer surveillance on perceptions of privacy and procedural justice.

Electronic workplace surveillance is raising concerns about privacy and fairness. Integrating research on electronic performance monitoring, procedural justice, and organizational privacy, the author proposes a framework for understanding reactions to technologies used to monitor and control employees. To test the framework's plausibility. temporary workers performed computer/Web-based tasks under varying levels of computer surveillance. Results indicated that monitoring job-relevant activities (relevance) and affording those who were monitored input into the process (participation) reduced invasion of privacy and enhanced procedural justice. Moreover, invasion of privacy fully mediated the effect of relevance and partially mediated the effect of participation on procedural justice. The findings are encouraging for integrating theory and research on procedural justice and organizational privacy.

Adult↗
PubMed2005

Multivariate parametric spatiotemporal models for county level breast cancer survival data.

In clustered survival settings where the clusters correspond to geographic regions, biostatisticians are increasingly turning to models with spatially distributed random effects. These models begin with spatially oriented frailty terms, but may also include further region-level terms in the parametrization of the baseline hazards or various covariate effects (as in a spatially-varying coefficients model). In this paper, we propose a multivariate conditionally autoregressive (MCAR) model as a mixing distribution for these random effects, as a way of capturing correlation across both the regions and the elements of the random effect vector for any particular region. We then extend this model to permit analysis of temporal cohort effects, where we use the term "temporal cohort" to mean a group of subjects all of whom were diagnosed with the disease of interest (and thus, entered the study) during the same time period (say, calendar year). We show how our spatiotemporal model may be efficiently fit in a hierarchical Bayesian framework implemented using Markov chain Monte Carlo (MCMC) computational techniques. We illustrate our approach in the context of county-level breast cancer data from 22 annual cohorts of women living in the state of Iowa, as recorded by the Surveillance, Epidemiology, and End Results (SEER) database. Hierarchical model comparison using the Deviance Information Criterion (DIC), as well as maps of the fitted county-level effects, reveal the benefit of our approach.

Adult↗
PubMed2005

Forensic interpretation of Y-chromosomal DNA mixtures.

The mathematical concept previously introduced for the forensic interpretation of DNA mixtures using non-associated genetic markers has been adapted to the assessment of haplotypes. Such calculus is required, for example, when Y-chromosomal markers are used in forensics. In addition to outlining the general mathematical framework, we devise two approaches to its practical computational implementation, involving either the inclusion-exclusion principle of probability theory or a recursion in the number of unknown contributors invoked. The two approaches scale differently, depending upon the complexity of the case and the diversity of the markers used. The performance of Y-chromosomal microsatellites (Y-STRs) as a means of trace donor discrimination has been assessed by simulation, using the derived formulas. Based upon data from the Y-chromosomal Haplotype Reference Database (YHRD), the exclusion chance of a non-contributor is shown to vary between 95% in the case of two contributors, and 70% for five contributors. With only one additional contributor, half of all contributing suspects would yield a log-likelihood ratio in favour of donorship of 1.61 or higher, although the median drops to 0.66 with four additional contributors. It must be emphasised that these estimates of the discriminatory power of Y-STRs are likely to be conservative since the simulations involved only haplotypes known to occur in YHRD.

Chromosomes, Human, Y↗
PubMed2006

What does it take to replace an old functioning information system with a new one? A case study.

PURPOSE: To investigate the case of a municipal wound care practice and the process of designing a specific computer documentation record system. In carrying out our kind of action research, creation of the system that integrate digital photos, was supposed to remake the old wound care documentation system and transform it into a more advanced and unified tool. METHODS: Ethnographic studies were conducted before and parallel to the design work. Nurse practitioners were involved in design and actively determining essentials of the computer artefact. Developmental Work Research (DWR) is the framework against which data from the work practice and system development where analyzed and interpreted. RESULTS: First, an old-fashioned information system (IS) within health care work will not successfully be replaced by a new one, unless the new is better "as a whole", that is, better supports work practices of a range of occupational and professional workers. Second, when designing information system for the public sector, system designers will almost always face dilemmas based on a contradiction between central, high level interest and a local level work-practice perspective. DISCUSSION: Our study reveals that the work practice of the municipal nurses is characterized by three distinctive features: High mobility, the need for face-to-face interaction in different locations, and a great variety of artefact usage. This implies that a new information system has to be "better as a whole" dealing with those characteristics.

Diffusion of Innovation↗
PubMed2004

Generalized image models and their application as statistical models of images.

A generalized image model (GIM) is presented. Images are represented as sets of four-dimensional (4D) sites combining position and intensity information, as well as their associated uncertainty and joint variation. This model seamlessly allows for the representation of both images and statistical models (such as those used for classification of normal/abnormal anatomy and for inter-patient registration), as well as other representations such as landmarks or meshes. A GIM-based registration method aimed at the construction and application of statistical models of images is proposed. A procedure based on the iterative closest point (ICP) algorithm is modified to deal with features other than position and to integrate statistical information. Furthermore, we modify the ICP framework by using a Kalman filter to efficiently compute the transformation. The initialization and update of the statistical model are also described. Preliminary results show the feasibility of the approach and its potentialities.

Algorithms↗
PubMedDate not supplied

Multi-scale models of local control of calcium induced calcium release.

Calcium-induced-calcium-release in cardiac myocytes is the release of Ca(2+) from the sarcoplasmic reticulum (SR) triggered by Ca(2+) entering the cell through L-type Ca(2+) channels. The Ca(2+) is released through ryanodine receptors which 'sense' local [Ca(2+)] in the small region (the diadic space) positioned between the t-tubules and the SR. The length-scale of a single diad is of the order of 10nm and the diffusion time-scale is of order of 1 micros with each cell containing approximately 10,000 diadic spaces which act independently. However, typically one is interested in Ca(2+) currents at the whole cell level and higher. This is a multi-scale problem and cannot be solved by direct computation. In this paper we develop a general framework for deriving approximate solutions of these models.

Animals↗
PubMed2005

Crystallized frameworks with giant pores: are there limits to the possible?

In the domain of porous solids with inorganic or hybrid frameworks, the combination of mastered chemistry and of computer simulations pushes forward the limits of the classical approach and allows the full determination from powder diffraction data of architectures with cells of several hundred thousand cubic angstroms with hierarchies of giant pores and unprecedented Langmuir surfaces. The different limits induced by this new approach are analyzed.

Journal Article↗
PubMed2004

Demonstrating the synergy of synthetic, mechanistic, and computational studies in a regioselective aniline synthesis.

Tri- and tetrasubstituted anilines are formed in good to excellent yields by the addition of ketones to vinamidinium salts (up to 98%). The reaction proceeds via the formation of dienone intermediates, which react to form an enamine with the liberated amine. In the case of a nitro, or dimethylaminomethylene substituent, the enamines undergo a facile electrocyclic ring closure to form a cyclohexadiene, which goes on to form anilines with a high degree of selectivity (up to 50:1) with a minor competing pathway proceeding via the enol providing phenols. Competition experiments using isotopic substitution reveal that the rate determining step en route to dienone is enol/enolate addition to the vinamidinium salt, which is characterized by an inverse secondary isotope effect (k(H/D) 0.7-0.9). Computational studies have been used to provide a framework for understanding the reaction pathway. The original proposal for a [1,5]-H shift was ruled out on the basis of the calculations, which did not locate a thermally accessible transition state. The minimum energy conformation of the enamine is such that a facile electrocyclic ring closure is ensured, which is corroborated by the experimental studies. A framework for understanding the reaction pathway is presented.

Journal Article↗
PubMed2006

Quantification of intramolecular nonbonding interactions in organochalcogens.

Intramolecular nonbonding interactions between chalcogen atoms in a series of ortho substituted arylselenides (S/O...Se-Y, with Y = -Me, -CN, -Cl, and -F) are quantified using the coupled cluster CCSD(T)/cc-pVDZ level of theory. A homodesmic reaction method as well as an ortho-para approach are employed in evaluating the strength of intramolecular interactions. Comparison of the results obtained using the ab initio MP2 method and pure and hybrid density functional theories are performed with that of the coupled cluster values to assess the quality of different density functionals in evaluating the strength of nonbonding interactions. The interaction energies are found to be higher when the thioformyl group acts as the donor and the Se-F bond acts as the acceptor. In a given series with the same donor atom, the strength of the interaction follows the order Me < CN < Cl < F, exhibiting fairly high sensitivity to the group attached to selenium (Se-Y). Analysis of electron density at the S/O...Se bond critical point within the Atoms in Molecule framework shows a very good correlation with the computed intramolecular interaction energies.

Journal Article↗