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Results for “computational frameworks”

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At least 415 records · Page 23Linked to original sources

PubMed2004

Simplified methods of implant treatment in the edentulous lower jaw. Part II: Early loading.

BACKGROUND: Most implant treatment is performed with a two-stage surgical procedure. A disadvantage of these implant treatments is that they are time-consuming. PURPOSE: The aim of the present study was to evaluate the results of early loading in the edentulous mandible and to compare those results with treatment results of one-stage surgery followed by a healing period and with two-stage surgery. MATERIAL AND METHODS: The material comprises four treatment groups with a total of 108 patients with edentulous lower jaws and 432 implants. All patients were treated with Brånemark implants (Nobel Biocare AB, Gothenburg, Sweden) with a turned surface and fixed prostheses in the lower jaw, supported by four implants. The patients in group A were treated with a one-stage procedure, a two-piece implant, and a 3-month healing period before loading. Group B (control group) had a two-stage procedure, a two-piece implant, and a 3-month healing period. Group C had a one-stage procedure, a one-piece implant, and a 3-month healing period. Group D was treated with a one-stage surgical procedure, a two-piece implant, and early loading (within 3 weeks). All patients were provided with a Procera Implant Bridge (Nobel Biocare) with a framework made by computer-assisted milling of one piece of pure titanium. All patients have been followed up for 1 year. RESULTS: The survival rates were 93.2 to 93.3% in the experimental groups and 97.5% in the control group. The difference was not statistically significant. The measurements of the marginal bone level demonstrated a mean bone loss of 0.8 mm between fixture insertion and the 1-year examination in patients with early loading (group D) whereas the bone loss in patients who underwent a healing period before loading was 1.3 to 1.6 mm. The difference between the control group and the group with early loading was significant. CONCLUSIONS: Survival rates for patients treated with a one-stage procedure were lower than survival rates for patients treated according to a "classical concept," but the differences were not statistically significant. There was no difference between treatment results with one-piece and two-piece implants. The implant loss in patients with early loading was probably caused by overloading, and careful supervision of occlusal loading is recommended. Early loading gave significantly less marginal bone loss when compared with two-stage surgery.

Adult↗

PubMed2002

[CRANIO--development of a system for computer- and robot-assisted craniotomy].

In the framework of the DFG project CRANIO, we are dealing with the problems of computer-assisted planning and robot-assisted realization of craniotomy, with optional skull reconstruction. A CT dataset was obtained from a phantom skull model and basic operation planning as well as different registration methods were performed. As one option it is possible to mill a contour on the skull or even to remove the entire area with a robot-guided microsurgical milling tool. In this context, work space tests were performed with a hexapod parallel robot. The milling of any contour geometry could be realized with different tool angles using the existing CRIGOS robot system without additional axes.

Computer Simulation↗

PubMed2000

Federation of the Person Identification Service between enterprises.

The Person Identification Service (PIDS) is a standard that has been adopted by the Object Management Group for managing identities of persons within a particular domain. That standard includes an interface that supports the ability to connect multiple PIDS servers together in a federated manner. The specification leaves great flexibility as to how to accomplish the federation. In this paper, we examine some of the federated approaches being considered by the Government Computer-based Patient Record Framework (G-CPR) project and discuss their advantages and disadvantages and the details of a specific, scalable approach to federation.

Government Agencies↗

PubMed1991

Population density and development potential in rural Zimbabwe: an assessment based on the 1969 and 1982 censuses.

"Based on 1969 and 1982 census data, this paper examines the spatial association between high rural population density and development potential in Zimbabwe and its significance for national development policy. A 1982 grid cell density map was compiled on the same geographical frame as an existing 1969 density map, yielding an intercensal density change map. A land classification map and a composite map of development constraints were rasterized on the same spatial framework and subjected to computer analysis. Areas of critically high (and generally increasing) densities showed strong spatial associations with areas of severe development constraints...."

Africa↗

PubMed2002

[Registration statistical program for the Rehabilitation Center for Patients with Cleft Lip and Palate in Uzbekistan].

The authors suggest an information computer support within the framework of a complex system for the diagnosis and treatment of patients with cleft lip and palate. This program will ensure operative information exchange for specialists of various spheres. Such information, united in the data base, will become the base for creation of a universal system of complex rehabilitation of patients with cleft lip and palate.

Cleft Lip↗

PubMed2005

Mathematical modeling and optimization of drug delivery from intratumorally injected microspheres.

PURPOSE: Paclitaxel is a highly promising phase-sensitive antitumor drug that could conceivably be improved by extended lower dosing as opposed to intermittent higher dosing. Although intratumoral delivery of paclitaxel to the whole tumor at different loads and rates has already been achieved, determining an optimal release mode of paclitaxel for tumor eradication remains difficult. This study set out to rationally design such an optimal microsphere release mode based on mathematical modeling. EXPERIMENTAL DESIGN: A computational reaction-diffusion framework was used to model drug release from intratumorally injected microspheres, drug transport and binding in tumor interstitum, and drug clearance by microvasculature and intracellular uptake and binding. RESULTS: Numerical simulations suggest that interstitial drug concentration is characterized by a fast spatially inhomogeneous rise phase, during which interstitial and intracellular binding sites are saturated, followed by a slow spatially homogeneous phase that is governed by the rate of drug release from microspheres. For zero-order drug release, the slow phase corresponds to a plateau drug concentration that is proportional to the ratio of the rate of blood clearance of drug to the rate of drug release from microspheres. Consequently, increasing the duration of intratumoral drug release extends the duration of cell exposure to the drug but lowers the plateau drug concentration. This tradeoff implies that intratumoral drug release can be designed to optimize tumor cell kill. Synthesizing our modeling predictions with published dose-response data, we propose an optimal protocol for the delivery of paclitaxel-loaded microspheres to small solid tumors.

Animals↗

PubMed2005

Multi-agent model for Indian rural health care.

PURPOSE: The objective of this paper is to present a model that uses multi-agent system (MAS) technology to assist doctors based at rural areas to receive timely expert opinions from specialist doctors working in medical institutions like the Postgraduate Institute of Medical Research, Chandigarh or the All India Institute of Medical Sciences, New Delhi. DESIGN/METHODOLOGY/APPROACH: A MAS is a software entity wherein agent metaphor is used to represent human-like intelligence and behavior. These agents are distributed over geographical areas and are part of software running at these sites. The foundation for this model lies in the fact that medical intelligence is distributed in nature and, if it is possible to bring this knowledge together, it could prove to be advantageous in providing improved health care to those people in rural areas. A few existing research works are included to demonstrate the usage of MAS in health care. FINDINGS: It has been observed that the health scenario in India is ranked poor world-wide by international organizations and, with the increasing population, this will worsen. RESEARCH LIMITATIONS/IMPLICATIONS: Initially, the aim is to concentrate on a few medical departments only. It can be extended into more detailed framework. PRACTICAL IMPLICATIONS: Physical computing and networking infrastructure are required for practical implementation along with training for the doctors. ORIGINALITY/VALUE: The primary beneficiaries of this system are likely to be those patients in the rural sector requiring expert medical opinion. The government health organizations will be able to provide quality medical facilities comparable with the medical facilities available in the developed nations. Currently this would seem to be a distant dream.

Delivery of Health Care↗

PubMed1996

A desktop image processing system for computer-assisted orthopedic surgery (DISOS).

Within the framework of our research activities in orthopedic surgery a PC-based imageprocessing system for the processing of x-ray computer-tomographic data has been developed. The system is used as a work platform for the investigations concerning interaction modalities, strategies and techniques for an efficient planning and execution of surgical interventions in orthopedic surgery by means of individual templates. The method of individual templates has been presented in /1,2/ and will not be subject of this paper.

Computer Peripherals↗

PubMed2004

GiPSi: an open source/open architecture software development framework for surgical simulation.

In this paper we propose an open source/open architecture framework for developing organ level surgical simulations. Our goal is to facilitate shared development of reusable models, to accommodate heterogeneous models of computation, and to provide a framework for interfacing multiple heterogeneous models. The framework provides an intuitive API for interfacing models with spatial relationships. It is specifically designed to be independent of the specifics of the modeling methods used and therefore facilitates seamless integration of heterogeneous models and processes. Furthermore, each model has separate geometries for visualization, simulation, and interfacing, allowing the modeler choose the most natural geometric representation for each case.

Computer Simulation↗

PubMed1998

Constrained optimization for neural map formation: a unifying framework for weight growth and normalization.

Computational models of neural map formation can be considered on at least three different levels of abstraction: detailed models including neural activity dynamics, weight dynamics that abstract from the neural activity dynamics by an adiabatic approximation, and constrained optimization from which equations governing weight dynamics can be derived. Constrained optimization uses an objective function, from which a weight growth rule can be derived as a gradient flow, and some constraints, from which normalization rules are derived. In this article, we present an example of how an optimization problem can be derived from detailed nonlinear neural dynamics. A systematic investigation reveals how different weight dynamics introduced previously can be derived from two types of objective function terms and two types of constraints. This includes dynamic link matching as a special case of neural map formation. We focus in particular on the role of coordinate transformations to derive different weight dynamics from the same optimization problem. Several examples illustrate how the constrained optimization framework can help in understanding, generating, and comparing different models of neural map formation. The techniques used in this analysis may also be useful in investigating other types of neural dynamics.

Animals↗

PubMed2005

Proposal for a framework for optimizing artificial environments based on physiological feedback.

We propose and then evaluate a new framework for finding the physical parameters of an artificial environment which give rise to given target physiological characteristics. We assume that a human is a system that takes as inputs the physical parameters of an artificial environment and outputs physiological parameters in response. We define our task as the inverse problem; we must find the best inputs from given target outputs. Our proposed framework solves the inverse problem using evolutionary computation techniques to optimize an artificial environment. We evaluate this framework using a simulation with a vibration environment and verify that it works.

Environment, Controlled↗

PubMed1995

Coevolutionary computation.

This article proposes a general framework for the use of coevolution to boost the performance of genetic search. It combines coevolution with yet another biologically inspired technique, called lifetime fitness evaluation (LTFE). Two unrelated problems--neural net learning and constraint satisfaction--are used to illustrate the approach. Both problems use predator-prey interactions to boost the search. In contrast with traditional "single population" genetic algorithms (GAs), two populations constantly interact and co-evolve. However, the same algorithm can also be used with different types of co-evolutionary interactions. As an example, the symbiotic coevolution of solutions and genetic representations is shown to provide an elegant solution to the problem of finding a suitable genetic representation. The approach presented here greatly profits from the partial and continuous nature of LTFE. Noise tolerance is one advantage. Even more important, LTFE is ideally suited to deal with coupled fitness landscapes typical for coevolution.

Algorithms↗

PubMedDate not supplied

Consumer informatics in chronic illness.

OBJECTIVE: To explore the informatic requirements in the home care of chronically ill patients. DESIGN: A number of strategies were deployed to help evoke a picture of home care informatics needs: A detailed questionnaire evaluating informational needs and assessing programmable technologies was distributed to a clinic population of parents of children with cancer. Open ended questionnaires were distributed to medical staff and parents soliciting a list of questions asked of medical staff. Parent procedure training was observed to evaluate the training dialog, and parents were observed interacting with a prototype information and education computer offering. RESULTS: Parents' concerns ranged from the details of managing day to day, to conceptual information about disease and treatment, to management of psychosocial problems. They sought information to solve problems and to provide emotional support, which may create conflicts of interest when the material is threatening. Whether they preferred to be informed by a doctor, nurse, or another parent depended on the nature of the information. Live interaction was preferred to video, which was preferred to text for all topics. Respondents used existing technologies in a straightforward way but were enthusiastic about the proposed use of computer technology to support home care. Multimedia solutions appear to complement user needs and preferences. CONCLUSION: Consumers appear positively disposed toward on-line solutions. On-line systems can offer breadth, depth and timeliness currently unattainable. Patients should be involved in the formation and development process in much the same way that users are involved in user-centered computer interface design. A generic framework for patient content is presented that could be applied across multiple disorders.

Adaptation, Psychological↗

PubMed2002

[The 3D PACS image system based on pipeline framework].

We put forward an image rendering system based on pipeline framework for processing and displaying medical images. Compared to original computer graphics algorithms divided into volume rendering and surface rendering, this framework can effectively comprehend methods of computer graphics and image processing, import some new concepts such as vertex buffer, pixel buffer and texture buffer. We implement Shaded Surface Display, Maximum Intensity Projection, Digitally Reconstructed Radiography, Multi planar Reformation, Curved Planar Reformation and Interactive Virtual Endoscopy in our new developed PACS image system.

Algorithms↗

PubMed2005

A user-centered framework for redesigning health care interfaces.

Numerous health care systems are designed without consideration of user-centered design guidelines. Consequently, systems are created ad hoc, users are dissatisfied and often systems are abandoned. This is not only a waste of human resources, but economic resources as well. In order to salvage such systems, we have combined different methods from the area of computer science, cognitive science, psychology, and human-computer interaction to formulate a framework for guiding the redesign process. The paper provides a review of the different methods involved in this process and presents a life cycle of our redesign approach. Following the description of the methods, we present a case study, which shows a successfully applied example of the use of this framework. A comparison between the original and redesigned interfaces showed improvements in system usefulness, information quality, and interface quality.

Artificial Intelligence↗

PubMed1999

A framework and tools for authoring, editing, documenting, sharing, searching, navigating, and executing computer-based clinical guidelines.

With the spread of managed care and integrated delivery networks, an increased emphasis has been placed on the cost-effectiveness of clinical practices. The need has been recognized to use guidelines to support education, and to integrate them into clinical practice. A specification for guideline representation that would facilitate computer-based clinical guideline sharing has been developed by the InterMed Collaboratory. Called GLIF (GuideLine Interchange Format), this specification and its proposed extensions have been the basis for our implementation of a framework and suite of integrated software tools for guideline authoring and editing, packaging in XML, Internet distribution, navigation, eligibility determination, and automatic execution.

Eligibility Determination↗

PubMed1999

Merging multiple institutions: information architecture problems and solutions.

Amalgamating organizations face great challenges when trying to merge their formerly separate information systems. An architectural approach is essential in order to understand the business process and data implications of the new organization's business decisions and application choices. HL7 is useful as a common messaging standard, but does not help to reconcile conflicting local identifier coding systems. The Information Services department has an important role in catalyzing decisions about inconsistent business processes and conflicting universal coding systems within an enterprise framework.

Computer Systems↗

PubMed2001

End-user support: a necessary issue in the implementation and use of EPR systems.

A successful integration of an IT-system is dependent not only of the quality of the information and the user interface features of the system but also of the organizations ability to support the users learning process. As IT is becoming more and more pervasive in the Health Care sector as such there is a need for a systematic approach to the question on how to support end-users. Based on an empirical study of an implementation process in a Danish Primary Health Care Services the concept of end-user support is discussed and it is argued that there is a need for a distinction between different kinds of support depending of the type of activity involved. First the organizations strategy for learning when the system was implemented is described. The evaluation of the learning strategy revealed that there was a need for different kinds of knowledge involving qualitatively different kinds of learning. Second the area of end-user support is discussed and it is argued that the common understanding of end-user support as something provided by DP staff, vendors or manuals are to narrow. Third a more differentiated way of thinking of support that link the need for different kind of knowledge and learning processes to different kinds of support is proposed. Finally Activity Theory is put forward as a possible basis that provide the opportunity of discussing issues belonging to different kinds of end-user support within an integrated framework.

Computer User Training↗