Increased fuel economy in transportation systems by use of energy management. Volume II - digital automotive propulsion simulator programs and description.

Transportation Department, Washington, D.C.

Graphical remote-access simulation system (GRASS), the communication and monitor components (GASP/GLASP).

"Supported in part by contract U.S. AEC AT(11-1)1469."

Parallel simulation of digital systems.

Includes bibliographical references.

The use of digital techniques for flight control; a discussion prepared for SAE Committee A-18 on Aerospace Vehicle Flight Control Systems.

Mode of access: Internet.

The effect of the ionosphere on communication, navigation, and surveillance systems : based on Ionospheric Effects Symposium, 5-7 May 1987 /

Mode of access: Internet.

Digital processes for sampled data systems.

Includes bibliography.

Towards Automation in Digital Investigations : Seeking Efficiency in Digital Forensics in Mobile and Cloud Environments

Cybercrime and related malicious activity in our increasingly digital world has become more prevalent and sophisticated, evading traditional security mechanisms. Digital forensics has been proposed to help investigate, understand and eventually mitigate such attacks. The practice of digital forensics, however, is still fraught with various challenges. Some of the most prominent of these challenges include the increasing amounts of data and the diversity of digital evidence sources appearing in digital investigations. Mobile devices and cloud infrastructures are an interesting specimen, as they inherently exhibit these challenging circumstances and are becoming more prevalent in digital investigations today. Additionally they embody further characteristics such as large volumes of data from multiple sources, dynamic sharing of resources, limited individual device capabilities and the presence of sensitive data. These combined set of circumstances make digital investigations in mobile and cloud environments particularly challenging. This is not aided by the fact that digital forensics today still involves manual, time consuming tasks within the processes of identifying evidence, performing evidence acquisition and correlating multiple diverse sources of evidence in the analysis phase. Furthermore, industry standard tools developed are largely evidence-oriented, have limited support for evidence integration and only automate certain precursory tasks, such as indexing and text searching. In this study, efficiency, in the form of reducing the time and human labour effort expended, is sought after in digital investigations in highly networked environments through the automation of certain activities in the digital forensic process. To this end requirements are outlined and an architecture designed for an automated system that performs digital forensics in highly networked mobile and cloud environments. Part of the remote evidence acquisition activity of this architecture is built and tested on several mobile devices in terms of speed and reliability. A method for integrating multiple diverse evidence sources in an automated manner, supporting correlation and automated reasoning is developed and tested. Finally the proposed architecture is reviewed and enhancements proposed in order to further automate the architecture by introducing decentralization particularly within the storage and processing functionality. This decentralization also improves machine to machine communication supporting several digital investigation processes enabled by the architecture through harnessing the properties of various peer-to-peer overlays. Remote evidence acquisition helps to improve the efficiency (time and effort involved) in digital investigations by removing the need for proximity to the evidence. Experiments show that a single TCP connection client-server paradigm does not offer the required scalability and reliability for remote evidence acquisition and that a multi-TCP connection paradigm is required. The automated integration, correlation and reasoning on multiple diverse evidence sources demonstrated in the experiments improves speed and reduces the human effort needed in the analysis phase by removing the need for time-consuming manual correlation. Finally, informed by published scientific literature, the proposed enhancements for further decentralizing the Live Evidence Information Aggregator (LEIA) architecture offer a platform for increased machine-to-machine communication thereby enabling automation and reducing the need for manual human intervention.

A COMUNICAÇÃO PODE SALVAR VIDAS: ALERTAS ANTECIPADOS DE EMERGÊNCIAS CLIMÁTICAS PELA TELEVISÃO DIGITAL INTERATIVA BRASILEIRA

Alertas Antecipados de Emergência são elementos importantes na redução de riscos de desastres, evitando a perda de vidas e reduzindo seu impacto econômico e material. Dentre os meios de comunicação mais eficazes para geração de alertas antecipados, a televisão digital com sua capacidade de emissão de um para muitos e ainda com suas possibilidades de gerar informações reativas com dados enviados pelo mesmo sinal de TV é, no momento, o estado da arte para ajudar a população em situações de risco, comprovado através de estudos comparativos entre os sistemas de alerta de emergência existentes hoje em todo o mundo. Neste trabalho são comparados os sistemas japonês e norte-americano, sendo que os referenciais teóricos apresentados focalizam o processo comunicacional de uma informação de emergência, a partir de diversas teorias que fundamentam o processo de comunicação em situações de crise, com os quais chegou-se à conclusão de que a tecnologia de televisão Digital Brasileira, juntamente com a infraestrutura essencial para detecção de riscos e confiabilidade para a geração de alertas antecipados já existente, dispõe de todo o ferramental necessário para a criação de um sistema nacional. Por fim são apresentadas as indicações iniciais para a criação de um modelo para uma comunicação eficaz e efetiva de informações de emergência destinado à população brasileira.

Impact of longitudinal power budget in coherent transmission systems employing digital back-propagation

We report the impact of longitudinal signal power profile on the transmission performance of coherently-detected 112 Gb/s m-ary polarization multiplexed quadrature amplitude modulation system after compensation of deterministic nonlinear fibre impairments. Performance improvements up to 0.6 dB (Q(eff)) are reported for a non-uniform transmission link power profile. Further investigation reveals that the evolution of the transmission performance with power profile management is fully consistent with the parametric amplification of the amplified spontaneous emission by the signal through four-wave mixing. In particular, for a non-dispersion managed system, a single-step increment of 4 dB in the amplifier gain, with respect to a uniform gain profile, at similar to 2/3(rd) of the total reach considerably improves the transmission performance for all the formats studied. In contrary a negative-step profile, emulating a failure (gain decrease or loss increase), significantly degrades the bit-error rate.

Impact of signal-ASE four-wave mixing on the effectiveness of digital back-propagation in 112 Gb/s PM-QPSK systems

Limitations in the performance of coherent transmission systems employing digital back-propagation due to four-wave mixing impairments are reported for the first time. A significant performance constraint is identified, originating from four-wave mixing between signals and amplified spontaneous emission noise which induces a linear increase in the standard deviation of the received field with signal power, and linear dependence on transmission distance.

Digital business reporting standards:mapping the battle in France

Government agencies use information technology extensively to collect business data for regulatory purposes. Data communication standards form part of the infrastructure with which businesses must conform to survive. We examine the development of, and emerging competition between, two open business reporting data standards adopted by government bodies in France; EDIFACT (incumbent) and XBRL (challenger). The research explores whether an incumbent may be displaced in a setting in which the contention is unresolved. We apply Latour’s (1992) translation map to trace the enrolments and detours in the battle. We find that regulators play an important role as allies in the development of the standards. The antecedent networks in which the standards are located embed strong beliefs that become barriers to collaboration and fuel the battle. One of the key differentiating attitudes is whether speed is more important than legitimacy. The failure of collaboration encourages competition. The newness of XBRL’s technology just as regulators need to respond to an economic crisis and its adoption by French regulators not using EDIFACT create an opportunity for the challenger to make significant network gains over the longer term. ANT also highlights the importance of the preservation of key components of EDIFACT in ebXML.

Advanced perturbation technique for digital backward propagation in WDM systems

An improved digital backward propagation (DBP) is proposed to compensate inter-nonlinear effects and dispersion jointly in WDM systems based on an advanced perturbation technique (APT). A non-iterative weighted concept is presented to replace the iterative in analytical recursion expression, which can dramatically simplify the complexity and improve accuracy compared to the traditional perturbation technique (TPT). Furthermore, an analytical recursion expression of the output after backward propagation is obtained initially. Numerical simulations are executed for various parameters of the transmission system. The results indicate that the advanced perturbation technique will relax the step size requirements and reduce the oversampling factor when launch power is higher than -2 dBm. We estimate this technique will reduce computational complexity by a factor of around seven with respect to the conventional DBP. © 2013 Optical Society of America.