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At least 631 records · Page 35Linked to original sources
PubMed2006

A notary archive model for secure preservation and distribution of electrically signed patient documents.

The healthcare industry is moving from paper-based documentation into the digital era. Electronic health records (EHR) are playing a major role in this development. Electronic health records will not only to be shared among a growing number of healthcare providers but they have also to be archived over long periods of time. The required life cycle depends of national regulations, but typically the preservation time of patient data varies between 20 and 100 years. Availability, integrity, confidentiality and non-repudiation of stored data over these lengthy preservation periods needs to be fully proven, both to preclude loss and also ensure the ability to read and understand content is maintained. This document describes a co-operative trusted notary archive (TNA) which receives granular health data from different EHR-systems, stores data together with associated meta-information for long periods and distributes granular EHR-data objects. TNA communicates with EHR-systems and external users via archive request and distribution messages. TNA can store objects in XML-format and prove the non-repudiation and integrity of stored data with the help of event records, Time-stamps and archive e-signatures.

Access to Information↗
PubMed2005

Spatial-temporal modeling of malware propagation in networks.

Network security is an important task of network management. One threat to network security is malware (malicious software) propagation. One type of malware is called topological scanning that spreads based on topology information. The focus of this work is on modeling the spread of topological malwares, which is important for understanding their potential damages, and for developing countermeasures to protect the network infrastructure. Our model is motivated by probabilistic graphs, which have been widely investigated in machine learning. We first use a graphical representation to abstract the propagation of malwares that employ different scanning methods. We then use a spatial-temporal random process to describe the statistical dependence of malware propagation in arbitrary topologies. As the spatial dependence is particularly difficult to characterize, the problem becomes how to use simple (i.e., biased) models to approximate the spatially dependent process. In particular, we propose the independent model and the Markov model as simple approximations. We conduct both theoretical analysis and extensive simulations on large networks using both real measurements and synthesized topologies to test the performance of the proposed models. Our results show that the independent model can capture temporal dependence and detailed topology information and, thus, outperforms the previous models, whereas the Markov model incorporates a certain spatial dependence and, thus, achieves a greater accuracy in characterizing both transient and equilibrium behaviors of malware propagation.

Algorithms↗
PubMed2005

GEMSS: grid-infrastructure for medical service provision.

OBJECTIVES: The European GEMSS Project is concerned with the creation of medical Grid service prototypes and their evaluation in a secure service-oriented infrastructure for distributed on demand/supercomputing. Key aspects of the GEMSS Grid middleware include negotiable QoS support for time-critical service provision, flexible support for business models, and security at all levels in order to ensure privacy of patient data as well as compliance to EU law. METHODS: The GEMSS Grid infrastructure is based on a service-oriented architecture and is being built on top of existing standard Grid and Web technologies. The GEMSS infrastructure offers a generic Grid service provision framework that hides the complexity of transforming existing applications into Grid services. For the development of client-side applications or portals, a pluggable component framework has been developed, providing developers with full control over business processes, service discovery, QoS negotiation, and workflow, while keeping their underlying implementation hidden from view. RESULTS: A first version of the GEMSS Grid infrastructure is operational and has been used for the set-up of a Grid test-bed deploying six medical Grid service prototypes including maxillo-facial surgery simulation, neuro-surgery support, radio-surgery planning, inhaled drug-delivery simulation, cardiovascular simulation and advanced image reconstruction. CONCLUSIONS: The GEMSS Grid infrastructure is based on standard Web Services technology with an anticipated future transition path towards the OGSA standard proposed by the Global Grid Forum. GEMSS demonstrates that the Grid can be used to provide medical practitioners and researchers with access to advanced simulation and image processing services for improved preoperative planning and near real-time surgical support.

Access to Information↗
PubMed2003

Beyond PACS: getting images to referring physicians.

The digital imaging hospital has the potential advantage that imaging studies are available anytime, and anywhere they are needed, with negligible loss. Fulfilling this promise in reality, however, presents challenges as described in this paper. No single best formula for successful deployment exists, since each institution is unique, and its medical staff may have varying preferences. This requires a collaborative team approach to design a solution acceptable to all parties, inside and outside of radiology. We have attempted to identify the significant issues. In addition, hardware and software technology continuously evolve and improve. What is clear is that all institutions will adopt this technology for the reasons described. The successful implementations will be those that are collaboratively and thoughtfully designed. User training of all members of the healthcare team involved with image study access is essential.

Computer Security↗
PubMed1998

Teleworks: a CSCW application for remote medical diagnosis support and teleconsultation.

The present paper describes methods for the design of both synchronous and asynchronous computer-supported cooperative work (CSCW) procedures suitable for the medical application area and specifically for the purpose of medical teleconsultation and remote diagnosis support. The experimental implementation of a CSCW system built upon a PC/Windows platform is detailed as an example of a low-cost system suitable for adoption in a wide range of medical teleconsultation applications.

Computer Communication Networks↗
PubMed2005

Digital watermarking robust to geometric distortions.

In this paper, we present two watermarking approaches that are robust to geometric distortions. The first approach is based on image normalization, in which both watermark embedding and extraction are carried out with respect to an image normalized to meet a set of predefined moment criteria. We propose a new normalization procedure, which is invariant to affine transform attacks. The resulting watermarking scheme is suitable for public watermarking applications, where the original image is not available for watermark extraction. The second approach is based on a watermark resynchronization scheme aimed to alleviate the effects of random bending attacks. In this scheme, a deformable mesh is used to correct the distortion caused by the attack. The watermark is then extracted from the corrected image. In contrast to the first scheme, the latter is suitable for private watermarking applications, where the original image is necessary for watermark detection. In both schemes, we employ a direct-sequence code division multiple access approach to embed a multibit watermark in the discrete cosine transform domain of the image. Numerical experiments demonstrate that the proposed watermarking schemes are robust to a wide range of geometric attacks.

Algorithms↗
PubMed2006

Still-image watermarking robust to local geometric distortions.

Geometrical distortions are the Achilles heel for many watermarking schemes. Most countermeasures proposed in the literature only address the problem of global affine transforms (e.g., rotation, scaling, and translation). In this paper, we propose an original blind watermarking algorithm robust to local geometrical distortions such as the deformations induced by Stirmark. Our method consists in adding a predefined additional information to the useful message bits at the insertion step. These additional bits are labeled as resynchronization bits or reference bits and they are modulated in the same way as the information bits. During the extraction step, the reference bits are used as anchor points to estimate and compensate for small local and global geometrical distortions. The deformations are approximated using a modified basic optical flow algorithm.

Algorithms↗
PubMed2004

A neural-network approach for visual cryptography and authorization.

In this paper, we propose a neural-network approach for visual authorization, which is an application of visual cryptography (VC). The scheme contains a key-share and a set of user-shares. The administrator owns the key-share, and each user owns a user-share issued by the administrator from the user-share set. The shares in the user-share set are visually indistinguishable, i.e. they have the same pictorial meaning. However, the stacking of the key-share with different user-shares will reveal significantly different images. Therefore, the administrator (in fact, only the administrator) can visually recognize the authority assigned to a particular user by viewing the information appearing in the superposed image of key-share and user-share. This approach is completely different from traditional VC approaches. The salient features include: (i) the access schemes are described using a set of graytone images, and (ii) the codebooks to fulfil them are not required; and (iii) the size of share images is the same as the size of target image.

Algorithms↗
PubMed2004

Decryption of pure-position permutation algorithms.

Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation algorithm, we put forward an effective decryption algorithm for all pure-position permutation algorithms. First, a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices. Then, by using probability theory and algebraic principles, the decryption probability of pure-position permutation algorithms is verified theoretically; and then, by defining the operation system of fuzzy ergodic matrices, we improve a specific decryption algorithm. Finally, some simulation results are shown.

Algorithms↗
PubMed1994

ScriptWriter. A relational database to manage outpatient medical treatment.

ScriptWriter is database software designed to replicate the process of a physician writing a prescription. The software also includes standard demographic and progress note information; however the focus of the software is on automating the process of writing prescriptions. The software is especially adept at creating patient medication lists, generating medication histories and keeping track of medication expiration dates. Other strengths include its ability to organize patient assignments and assist in the generation of progress notes. The application is network capable and fully graphical. A psychiatric outpatient clinic is currently using the software. Practitioners in non-psychiatric settings can also benefit from the software.

Ambulatory Care↗