Optimizing Segment Based Document Protection (Corrected Version)

In this paper we provide a corrected and generalized version of the scheme presented at SOFSEM\u272012 in our paper ``Optimizing Segment Based Document Protection\u27\u27 (SOFSEM 2012: Theory and Practice of Computer Science, LNCS 7147, pp. 566-575). We develop techniques for protecting documents with restricted access rights. In these documents so called \emph{segments} are encrypted. Different segments may be encrypted with different keys so that different user may be given different \emph{access rights}. Hierarchy of access rights is represented by means of a directed acyclic \emph{access graph}. The segments are encrypted with keys - where each key corresponds to one node in the access graph. The main feature of the access graph is that if there is an arch $\overrightarrow{AB}$ in the graph, then all segments labelled with $B$ can be decrypted with the key corresponding to node $A$. We show how to minimize the space overhead necessary for auxiliary keying information stored in the document. We provide an algorithm based on node disjoint paths in the access graph and key derivation based on one-way functions. Our current solution, based on maximal weighted matchings, provides an optimal solution for creating subdocuments, in case when frequency of creating each subdocument is known

Flight evaluation of two-segment approaches using area navigation guidance equipment

A two-segment noise abatement approach procedure for use on DC-8-61 aircraft in air carrier service was developed and evaluated. The approach profile and procedures were developed in a flight simulator. Full guidance is provided throughout the approach by a Collins Radio Company three-dimensional area navigation (RNAV) system which was modified to provide the two-segment approach capabilities. Modifications to the basic RNAV software included safety protection logic considered necessary for an operationally acceptable two-segment system. With an aircraft out of revenue service, the system was refined and extensively flight tested, and the profile and procedures were evaluated by representatives of the airlines, airframe manufacturers, the Air Line Pilots Association, and the Federal Aviation Adminstration. The system was determined to be safe and operationally acceptable. It was then placed into scheduled airline service for an evaluation during which 180 approaches were flown by 48 airline pilots. The approach was determined to be compatible with the airline operational environment, although operation of the RNAV system in the existing terminal area air traffic control environment was difficult

Optimización de operaciones y comunicaciones de red para sistemas de monitorización oceanográfica

[ES] Esta tesis se centra en los sistemas de monitoreo oceanográfico y la optimización de sus operaciones, especialmente sus comunicaciones de red. Se han desarrollado tres cuestiones de investigación, centrándolas en el proyecto Mission-oriented autonomous systems with small satellites for maritime sensing, surveillance and communication (MASSIVE). Se han aplicado herramientas de ingeniería de sistemas para comprender los componentes del sistema y sus interfaces. Específicamente, desarrollo de escenarios, análisis N-squared y Documento de Control de Interfaz. Además, se ha destacado el papel de una Interfaz de Usuario en sistemas operativos y se han desarrollado los requisitos de la Interfaz de Usuario para el sistema analizado, así como su primera iteración con Django.[EN] This thesis is concerned about oceanographic monitoring systems and the optimization of their operations, especially their network communications. Three research questions have been discussed, focusing them on the Mission-oriented autonomous systems with small satellites for maritime sensing, surveillance and communication (MASSIVE) system. Systems Engineering tools have been applied to shed an understanding of the system’s constituents and their interfaces. Specifically, scenario development, N-squared analysis, and Interface Control Document. Also, the important role of a User Interface in operational systems has been highlighted and the development of the User Interface requirements as well as the first iteration using Django.Carcelén Ferragut, S. (2020). Optimización de operaciones y comunicaciones de red para sistemas de monitorización oceanográfica. Universitat Politècnica de València. http://hdl.handle.net/10251/161633TFG

A model of quality service management for information systems

Tese de mestrado. Mestrado em Engenharia Electrotécnica e de Computadores (Área de especialização Tecnologias da Informação para Gestão Empresarial). Faculdade de Engenharia. Universidade do Porto. 200

Digital Image Access & Retrieval

The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio

Development and validation of a tool to assess the risk of QT drug-drug interactions in clinical practice

Background The exact risk of developing QTc-prolongation when using a combination of QTc-prolonging drugs is still unknown, making it difficult to interpret these QT drug-drug interactions (QT-DDIs). A tool to identify high-risk patients is needed to support healthcare providers in handling automatically generated alerts in clinical practice. The main aim of this study was to develop and validate a tool to assess the risk of QT-DDIs in clinical practice. Methods A model was developed based on risk factors associated with QTc-prolongation determined in a prospective study on QT-DDIs in a university medical center inthe Netherlands. The main outcome measure was QTc-prolongation defined as a QTc interval > 450 ms for males and > 470 ms for females. Risk points were assigned to risk factors based on their odds ratios. Additional risk factors were added based on a literature review. The ability of the model to predict QTc-prolongation was validated in an independent dataset obtained from a general teaching hospital against QTc-prolongation as measured by an ECG as the gold standard. Sensitivities, specificities, false omission rates, accuracy and Youden's index were calculated. Results The model included age, gender, cardiac comorbidities, hypertension, diabetes mellitus, renal function, potassium levels, loop diuretics, and QTc-prolonging drugs as risk factors. Application of the model to the independent dataset resulted in an area under the ROC-curve of 0.54 (95% CI 0.51-0.56) when QTc-prolongation was defined as > 450/470 ms, and 0.59 (0.54-0.63) when QTc-prolongation was defined as > 500 ms. A cut-off value of 6 led to a sensitivity of 76.6 and 83.9% and a specificity of 28.5 and 27.5% respectively. Conclusions A clinical decision support tool with fair performance characteristics was developed. Optimization of this tool may aid in assessing the risk associated with QT-DDIs.Clinical Pharmacy and Toxicolog