Type

Database

Creator

Date

Thumbnail

Search results

283 records were found.

The need for a computer-based information management system in a department of radiology is not new. For more than ten years now, it has been addressed by a variety of systems which all offer but partial solutions to the problem: Radiology Information System (RIS) for factual data, Picture Archiving and Communication System (PACS) for radiological images, voice-messaging system for verbal reports, etc. A multimedia information system is therefore required to integrate and expand the capabilities of each of these partial solutions. In this thesis, we investigate the information management aspects of such a multimedia information system. We characterize the radiological information, by identifying its components and their dynamic evolution. Based on this characterization, we apply concepts developed for the automated office environment t...
To diagnose patients with heart disease, cardiologists need to view the co-ordinated movements of various components of the heart, and check for narrowings and blockages in the coronary arteries. Echocardiography and Cardiac Angiography are two imaging modalities which permit visualization of these aspects of the heart. Currently, examinations performed with these modalities are stored on either 35mm cine film or VHS video cassette, making their review tedious and time consuming for the cardiologists. We propose a multimedia workstation to store the examinations and all related textual and graphical information in such a way as to permit convenient access. This information would be supported by a multimedia database which would allow for retrieval based on logical indices, such as patient name and examination date. This thesis details ...
The basic functions of a Geographic Information System (GIS) and the different ways that a GIS may be implemented are described. It surveys that GIS software packages that are currently in operation at the Goddard Space Flight Center and discusses the types of applications for which they are best suited. Future plans for in-house GIS research and development are outlined.
A geocoded data structure is a means for digitally representing a geographically referenced map or image. The characteristics of representative cellular, linked, and hybrid geocoded data structures are reviewed. The data processing requirements of Earth science projects at the Goddard Space Flight Center and the basic tools of geographic data processing are described. Specific ways that new geocoded data structures can be used to adapt these tools to scientists' needs are presented. These include: expanding analysis and modeling capabilities; simplifying the merging of data sets from diverse sources; and saving computer storage space.
Comment: 20 pages. Corrected typos and improved explanatory remarks at the end
In dimension $n>3$ we show the existence of a compactly supported potential in the differentiability class $C^\alpha$, $\alpha < \frac{n-3}2$, for which the solutions to the linear Schr\"odinger equation in $\R^n$, $$ -i\partial_t u = - \Delta u + Vu, \quad u(0)=f, $$ do not obey the usual $L^1\to L^{\infty}$ dispersive estimate. This contrasts with known results in dimensions $n \leq 3$, where a pointwise decay condition on $V$ is generally sufficient to imply dispersive bounds.
New convenient stability criteria are provided in this paper for a large class of finite difference approximations to initial-boundary value problems associated with the hyperbolic system u sub t = au sub x + Bu + f in the quarter plane x or = 0, t or = 0. Using the new criteria, stability is easily established for numerous combinations of well known basic schemes and boundary conditions, thus generalizing many special cases studied in recent literature.
New convenient stability criteria are provided in this paper for a large class of finite difference approximations to initial-boundary value problems associated with the hyperbolic system u sub t = au sub x + Bu + f in the quarter plane x or = 0, t or = 0. Using the new criteria, stability is easily established for numerous combinations of well known basic schemes and boundary conditins, thus generalizing many special cases studied in recent literature.
New convenient stability criteria are provided for a large class of finite difference approximations to initial-boundary value problems associated with the hyperbolic system u sub t = Au sub x + Bu + f in the quarter plane x greater than or equal to 0, t greater than or equal to 0. The criteria are used to easily establish stability for numerous combinations of well known basic schemes and boundary conditions, thus generalizing many special cases studied in the recent literature. A number of examples are examined, including the unitary unconditionally stable Crank-Nicholson scheme and an almost-dissipative unconditionally stable backward Euler scheme.
Want to know more?If you want to know more about this cutting edge product, or schedule a demonstration on your own organisation, please feel free to contact us or read the available documentation at http://www.keep.pt/produtos/retrievo/?lang=en