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PubMed1992

The analysis of distributed control and information processing in adaptive systems: a biologically motivated approach.

Biological systems have evolved hierarchical, distributed control structures that greatly enhance their adaptability. Two important determinants of biological adaptability considered here are: (i) the pattern of distribution of self-control capabilities; (ii) the degree of programmability of information processing. In this paper we model organizations as goal-oriented, adaptive systems, possessing properties similar to those of biological systems. We use the notion of implicit control (defined as the capability of self-control that is embedded in a system's own dynamics) in the analysis of the impact of specific patterns of distribution of control and information processing on the adaptability of organizations. A principle of design of organizational information systems, that captures important aspects of adaptability-preserving strategies of information processing in biological systems, is stated in terms of the implicit control concept.

Adaptation, Biological↗
PubMed1995

Applying a controlled medical terminology to a distributed, production clinical information system.

To maximize the value of computerized medical records systems, an organizing structure is needed. That structure can be provided by a controlled medical terminology (CMT). At Columbia-Presbyterian Medical Center, we have been employing a controlled medical terminology, our Medical Entities Dictionary (MED), to mediate the storage and retrieval of patient data and enable decision support applications. This paper describes how the MED is actually used for data management in our distributed clinical information systems environment. Our system tools which access the MED for production purposes facilitate the mapping of terms from many sources to a uniform representation of concepts and also return information about the relationships between concepts. Applications which access a CMT for production purposes should be optimized for performance in high volume settings, fault tolerant, synchronizable, extensible, portable, and maintainable. We briefly describe our system architecture and then demonstrate how we utilize the MED for translation and semantic information as data is moved into and out of our patient database. We discuss our current tools and present a preview of the next generation of applications which will manage access to the MED for our production systems.

Computer Communication Networks↗
PubMedDate not supplied

Analysis and modeling of information flow and distributed expertise in space-related operations.

Evolving space operations requirements and mission planning for long-duration expeditions require detailed examinations and evaluations of information flow dynamics, knowledge-sharing processes, and information technology use in distributed expert networks. This paper describes the work conducted with flight controllers in the Mission Control Center (MCC) of NASA's Johnson Space Center. This MCC work describes the behavior of experts in a distributed supervisory coordination framework, which extends supervisory control/command and control models of human task performance. Findings from this work are helping to develop analysis techniques, information architectures, and system simulation capabilities for knowledge sharing in an expert community. These findings are being applied to improve knowledge-sharing processes applied to a research program in advanced life support for long-duration space flight. Additional simulation work is being developed to create interoperating modules of information flow and novice/expert behavior patterns.

Communication↗
PubMed2006

The contradictory information on the distribution of non-disjunction and pre-division in female gametes.

Valuable information on the cytogenetic constitution of female gametes has been deduced from the direct, so-called conventional analysis of oocytes remaining unfertilized in programmes of assisted reproduction. Additional, indirect conclusions have become possible by PGD of the polar bodies. Both techniques provided evidence for the co-existence of two aneuploidy-causing mechanisms during first maternal meiosis; non-disjunction (ND) of bivalents results in the loss or gain of whole chromosomes in metaphase II complements, whereas a precocious division (pre-division, PD) of univalents leads to the loss or gain of single chromatids. As to the distribution of ND and PD, however, direct oocyte chromosome studies and PGD tell surprisingly different stories. Moreover, first and second polar body analyses contradict the data derived from DNA polymorphism studies concerning the distribution of first and second meiotic division errors. An increased awareness of these problems appears necessary because important decisions are made on the basis of PGD results.

Adult↗
PubMed1994

The networked multimedia textbook: distributing radiology multimedia information across the Internet.

OBJECTIVE: The purpose of this project was to create an approach for global radiology multimedia publishing using the internet that would address the two largest problems facing radiology multimedia publishers today: the high percentage of radiologists who are computer novices and the variety of personal computers (Macintosh, Microsoft Windows/IBM-PC, X-Windows, Amiga) whose software is incompatible. MATERIALS AND METHODS: We developed a client/server approach to multimedia publishing, the networked multimedia textbook, that has a simple booklike user interface to facilitate use by computer novices. Once created, a networked multimedia textbook can be viewed on all current popular personal computers. The networked multimedia textbook is based on the internet, World-Wide Web, Mosaic, and Wide Area Information Servers software technologies, all of which are in the public domain. RESULTS: We created six radiology networked multimedia textbooks. CONCLUSION: This networked multimedia textbook approach for the global distribution of multimedia radiology information brings the benefits of multimedia publishing on the Internet to radiologists today.

Computer Communication Networks↗
PubMed1996

Spatial information on dose distribution using multisectional dose-volume histograms.

Dose-volume histograms are useful tools to summarize the information on the dose profiles resulting within a target volume. However, the spatial relationships of the hot and the cold spots are blunted in the dose-volume histograms. This study tries to circumvent this problem using multisectional dose-volume histograms and highlight the utility of these in the optimization of a radiation therapy plan.

Brachytherapy↗
PubMed2006

Design aspects of a distributed clinical trials information system.

BACKGROUND: Clinical trials informatics has evolved through the development of multiple applications addressing distinct parts of the clinical trials cycle. This setting creates difficulties in the transport and sharing of data among applications that serve a common functionality. PURPOSE: We present an alternative approach for the design of clinical trials information systems consisting of loosely coupled components standing on a comprehensive model of the global clinical trial process. METHODS: We describe how such a structure is able to support the development and implementation of complex knowledge-driven modules, such as automated database query systems, reporting systems and intelligent data-analysis tools, and how currently available internet technologies may be used to support the independent development of applications and collaboration between researchers. RESULTS: These principles were applied to the development of a fully functional system that has been in production for eight years in a diversity of pharmaceutical and academic drug trials. Marked time savings in database set-up and statistical reporting have been documented, as well as good reliability in the selection of appropriate statistical methods to clinical trial data analysis. CONCLUSIONS: In order to meet the expected functionality and to avoid the proliferation of databases and software applications, clinical trials information systems need to be based on a generic model of clinical trials and on a distributed architecture.

Clinical Trials as Topic↗
PubMed2002

Egg distributions and the information a solitary parasitoid has and uses for its oviposition decisions.

Approximately three decades ago the question was first answered "whether parasitoids are able to assess the number or origin of eggs in a host" for a solitary parasitoid, Leptopilina heterotoma, by fitting theoretically derived distributions to empirical ones. We extend the set of different theoretically postulated distributions of eggs among hosts by combining searching modes and abilities in assessing host quality. In the models, parasitoids search either randomly (Poisson) (1) or by vibrotaxis (Negative Binomial) (2). Parasitoids are: (a) assumed to treat all hosts equally, (b) able to distinguish them in unparasitised and parasitised hosts only, (c) able to distinguish them by the number of eggs they contained, or (d) able to recognise their own eggs. Mathematically tractable combinations of searching mode (1 and 2) and abilities (a,b,c,d) result in seven different models (M1a, M1b, M1c, M1d, M2a, M2b and M2c). These models have been simulated for a varying number of searching parasitoids and various mean numbers of eggs per host. Each resulting distribution is fitted to all theoretical models. The model with the minimum Akaike's information criterion (AIC) is chosen as the best fitting for each simulated distribution. We thus investigate the power of the AIC and for each distribution with a specified mean number of eggs per host we derive a frequency distribution for classification. Firstly, we discuss the simulations of models including random search (M1a, M1b, M1c and M1d). For M1a, M1c and M1d the simulated distributions are correctly classified in at least 70% of all cases. However, in a few cases model M1b is only properly classified for intermediate mean values of eggs per host. The models including vibrotaxis as searching behaviour (M2a, M2b and M2c) cannot be distinguished from those with random search if the mean number of eggs per host is low. Among the models incorporating vibrotaxis the three abilities are detected analogously as in models with random search. Experiments with two species of solitary parasitoids (L. heterotoma and Asobara tabida) are conducted. All theoretically postulated distributions are separately fitted to the resulting experimental egg distributions. The AIC criterion is used to choose the best fitting theoretical distribution. For both parasitoid species the frequency distribution of best fitting models for experimental data is compared to the classification of distributions generated by simulations. This leads to the conclusion that both L. heterotoma and A. tabida are able to distinguish between parasitised and unparasitised hosts. For L. heterotoma the results point to an ability to assess the number of eggs in a host, whereas A. tabida does not seem to have this ability. This difference suggests that an egg is more valuable for L. heterotoma than for A. tabida.

Animals↗
PubMed1989

Cooperative regional program for distribution of poison prevention information and syrup of ipecac.

A regional program to distribute poison prevention information and syrup of ipecac to families that have regular contact with young children is described. In December 1985 the department of pharmacy services at Bristol Hospital in Connecticut proposed implementation of a poison prevention program targeted to families with young children (less than 12 years of age) in the hospital's five-town service area. A planning committee was created to define program goals and oversee operations. The committee decided that poison prevention kits consisting of an instructional booklet and a one-ounce bottle of syrup of ipecac would be distributed to selected residents of the five-town area, with individual instruction provided in the correct use of syrup of ipecac. Funding was provided principally by the hospital, with some additional money from private foundations. The project was named CAP (Combating Accidental Poisoning) and ran initially from December 1, 1986, to June 30, 1987. Kits were distributed in cooperation with area health-care professionals with whom families had regular contact, including pediatricians, family-practice physicians, and community pharmacies. Apart from the hospital pharmacy service itself, the most effective participants were pediatricians; family-practice physicians were highly ineffective. During the course of the initial CAP program 6610 kits were distributed, with 48.7% going to families considered at high risk for the occurrence of an accidental child poisoning. An ongoing program to distribute these kits to all newly delivered mothers and to all area pediatricians free of charge has resulted in more than 15,000 kits being distributed.(ABSTRACT TRUNCATED AT 250 WORDS)

Connecticut↗
PubMed2001

Towards integration of clinical decision support in commercial hospital information systems using distributed, reusable software and knowledge components.

PROBLEM: Clinicians' acceptance of clinical decision support depends on its workflow-oriented, context-sensitive accessibility and availability at the point of care, integrated into the Electronic Patient Record (EPR). Commercially available Hospital Information Systems (HIS) often focus on administrative tasks and mostly do not provide additional knowledge based functionality. Their traditionally monolithic and closed software architecture encumbers integration of and interaction with external software modules. Our aim was to develop methods and interfaces to integrate knowledge sources into two different commercial hospital information systems to provide the best decision support possible within the context of available patient data. METHODS: An existing, proven standalone scoring system for acute abdominal pain was supplemented by a communication interface. In both HIS we defined data entry forms and developed individual and reusable mechanisms for data exchange with external software modules. We designed an additional knowledge support frontend which controls data exchange between HIS and the knowledge modules. Finally, we added guidelines and algorithms to the knowledge library. RESULTS: Despite some major drawbacks which resulted mainly from the HIS' closed software architectures we showed exemplary, how external knowledge support can be integrated almost seamlessly into different commercial HIS. This paper describes the prototypical design and current implementation and discusses our experiences.

Abdominal Pain↗
PubMed1995

EM mixed model analysis of data from informatively censored normal distributions.

Maximum likelihood techniques using the EM algorithm are applied to correlated normally distributed survival data from a placebo-controlled, double-blind, dose-ranging crossover study to assess the short-term efficacy of an antianginal drug in patients with chronic stable angina. Censoring was informative and nonterminal and was not due to death or withdrawal from the study. Unlike previous approaches these techniques are mathematically and computationally tractable, do not require computations of high-dimensional integrals, and do not require the inversion of large matrices.

Algorithms↗
PubMed1981

Spatial distribution of afferent information to the anterior lobe of the cat's cerebellum.

In the decerebrate cat discharges of Purkinje cells with simple and complex spikes as well as granule cell discharges in the c1-zone of lobules Va, b and c of the cerebellar anterior lobe were analyzed during a passive movement of the cat's forepaw. Penetrations were made 50 micrometers apart along the mediolateral and parasagittal directions, the depth never exceeding 500 micrometers. The response of the Purkinje cells to the climbing fiber input was surprisingly constant, while simple spike responses of the same cells showed a great variability to the same input. The variability between granule cell discharges recorded at a 50 micrometer distance from each other was similar to that of the simple spikes of the Purkinje cell. It is assumed that because of a patchy distribution of excited granule cells, two neighbouring Purkinje cells may receive a different information via their parallel fiber inputs. This difference is considered to be responsible for the great variability of their responses to mossy fiber inputs.

Afferent Pathways↗
PubMed1988

Structuring strain data for storage and retrieval of information on fungi and yeasts in MINE, the Microbial Information Network Europe.

A distributed Microbial Information Network Europe (MINE) is being constructed by a number of major microbial culture collections in countries of the European Community, with the support of the Biotechnology Action Programme (BAP) of the Commission of the European Community. The representatives of the collections participating in MINE have agreed to adopt a general format for the computer storage and retrieval of strain data. This uniform format will facilitate the electronic combination and exchange of data from different collections in order to produce integrated catalogues and the use of identical commands to search the different databases. It is recommended to other collections who may wish to contribute data to the MINE network or between themselves. Three kinds of records can be linked to the leading 'species records': strain records, synonym records, and alternative morphonym records. A minimum data set of 30 fields (similar to the fields used for producing catalogues) is defined that facilitates the exchange of data between the national nodes and serves as a directory to strains available at other nodes. It is suggested that the full strain record comprise 99 fields, grouped in 12 blocks: internal administration--name--strain administration--status--environment and history--biological interactions--sexuality--properties (cytology, biomolecular data)--genotype and genetics--growth conditions--chemistry and enzymes--practical applications. Several fields are divided into subfields of different ranks. Delimiters are used either to separate a range of entries that have to be indexed or to divide an entry from the reference to its source or remarks that should not be indexed. The contents and structure of the fields proposed for filamentous fungi and yeasts are described and in some cases illustrated by examples. Uniformity of input is essential for indexed fields and desirable for non-indexed fields. Seven thesaurus files are envisaged to ensure consistency.

Data Collection↗
PubMed1997

The representational capacity of the distributed encoding of information provided by populations of neurons in primate temporal visual cortex.

It has been shown that it is possible to read, from the firing rates of just a small population of neurons, the code that is used in the macaque temporal lobe visual cortex to distinguish between different faces being looked at. To analyse the information provided by populations of single neurons in the primate temporal cortical visual areas, the responses of a population of 14 neurons to 20 visual stimuli were analysed in a macaque performing a visual fixation task. The population of neurons analysed responded primarily to faces, and the stimuli utilised were all human and monkey faces. Each neuron had its own response profile to the different members of the stimulus set. The mean response of each neuron to each stimulus in the set was calculated from a fraction of the ten trials of data available for every stimulus. From the remaining data, it was possible to calculate, for any population response vector, the relative likelihoods that it had been elicited by each of the stimuli in the set. By comparison with the stimuli actually shown, the mean percentage correct identification was computed and also the mean information about the stimuli, in bits, that the population of neurons carried on a single trial. When the decoding algorithm used for this calculation approximated an optimal, Bayesian estimate of the relative likelihoods, the percentage correct increased from 14% correct (chance was 5% correct) with one neuron to 67% with 14 neurons. The information conveyed by the population of neurons increased approximately linearly from 0.33 bits with one neuron to 2.77 bits with 14 neurons. This leads to the important conclusion that the number of stimuli that can be encoded by a population of neurons in this part of the visual system increases approximately exponentially as the number of cells in the sample increases (in that the log of the number of stimuli increases almost linearly). This is in contrast to a local encoding scheme (of "grandmother" cells), in which the number of stimuli encoded increases linearly with the number of cells in the sample. Thus one of the potentially important properties of distributed representations, an exponential increase in the number of stimuli that can be represented, has been demonstrated in the brain with this population of neurons. When the algorithm used for estimating stimulus likelihood was as simple as could be easily implemented by neurons receiving the population's output (based on just the dot product between the population response vector and each mean response vector), it was still found that the 14-neuron population produced 66% correct guesses and conveyed 2.30 bits of information, or 83% of the information that could be extracted with the nearly optimal procedure. It was also shown that, although there was some redundancy in the representation (with each neuron contributing to the information carried by the whole population 60% of the information it carried alone, rather than 100%), this is due to the fact that the number of stimuli in the set was limited (it was 20). The data are consistent with minimal redundancy for sufficiently large and diverse sets of stimuli. The implication for brain connectivity of the distributed encoding scheme, which was demonstrated here in the case of faces, is that a neuron can receive a great deal of information about what is encoded by a large population of neurons if it is able to receive its inputs from a random subset of these neurons, even of limited numbers (e.g. hundreds).

Algorithms↗
PubMed1997

Bhorugram (India): revisited. A 4 year follow-up of a computer-based information system for distributed MCH services.

Impact of a health informatics research project on the management and delivery of primary health care, focusing on maternal and child health care (MCH), was reported earlier in 1992, with encouraging results in terms of increased antenatal care coverage and decrease in Immunisation drop-outs. The software (MCHS) was based on essential data sets (EDS) to assist the care providers in information management for MCH care. The site was revisited after four years to evaluate the status of the project and to ascertain whether computers were still in use and was the dispensary staff using the MCHS package or not? The results are presented in this paper to demonstrate that 'information is a difference that makes a difference'. Information generated by the MCHS acted as a catalyst for behavioural change in the community from indifferent users to active users of the health care services. This is reflected by the increased acceptance of antenatal care, 80% fully immunised child (FIC) and participation in other primary health care activities.

Adolescent↗
PubMed2000

Non-iterative methods incorporating a priori source distribution and data information for suppression of image noise and artefacts in 3D SPECT.

Non-iterative methods have been developed for image reconstruction in 3D SPECT with uniform attenuation and distance-dependent spatial resolution. It was observed that these methods can, in general, be susceptible to data noise and other errors, yielding conspicuous image artefacts. In this work, we developed and evaluated a regularized inverse-filtering approach for effective suppression of noise and artefacts in 3D SPECT images without significantly compromising image resolution. The proposed approach allows the incorporation of a priori random image field and data information and can thus robustly control the degree of suppression of noise and artefacts in 3D SPECT images. Using computer simulations, we evaluated and compared quantitatively images reconstructed from data sets of various noise levels by the use of the proposed methods and the existing non-iterative methods. These numerical results clearly demonstrated that the proposed regularized inverse-filtering approach can effectively suppress image noise and artefacts that plague the existing non-iterative methods, thus yielding quantitatively more accurate 3D SPECT images. The proposed regularized inverse-filtering approach can also be generalized to other imaging modalities.

Algorithms↗