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671.
A novel thin line detection algorithm for use in low-altitude aerial vehicles is presented. This algorithm is able to detect thin obstacles such as cables, power lines, and wires. The system is intended to be used during urban search and rescue operations, capable of dealing with low-quality images, robust to image clutter, bad weather, and sensor artifacts. The detection process uses motion estimation at the pixel level, combined with edge detection, followed by a windowed Hough transform. The evidence of lines is tracked over time in the resulting parameter spaces using a dynamic line movement model. The algorithm's receiver operating characteristic curve (ROC) is shown, based on a multi-site dataset with 86 videos with 10160 wires spanning in 5576 frames.  相似文献   
672.
Earth as a planet under firm control of life processes since more than 3 Ga has evolved global biogeochemical cycles, biogeomorphogenetic processes and structures also called plates or global tectonics including global climate and movement of water masses. These processes have deep impact on the shape and thickness of continental land masses as well as the chemistry and mineralogy of the crust and upper mantle. Biogenerated rock structures in this sense can be visualised through the analysis of sedimentary rock structures exhibiting e.g., biogenerated stromatolites, onkolites, oolites or cementing structures of sandstones which clearly preserve biochemical processes and biophysical structures. Further the chemical composition including the segregation of mineral layers, ore deposits, sedimentary and metamorphic rocks and granites hint to sun powered energy storage (gas, gas hydrates, hydrocarbons, coal) and tectonic processes initiated or at least modified through the enormous input of external energy through reduced carbon and iron compounds. One can state with considerable reliability that a planet under control of life must exhibit rock chemistry, mineralogy and structures typical for the impact of life on the geodynamic cycles. This includes the idea of top-down geotectonics instead of bottom-up processes.  相似文献   
673.
Today, every modern organization aspires to improve its performance through better use of information technology. As communication technology improves, organizations can operate over wider distances and can even assemble operational components on an ad-hoc basis to meet requirements of a specific objective. Future air traffic communication studies are already discussing whether to operate IP networks that are combining voice and data transport. The problem is that although voice and data are using a common infrastructure, they remain separate at the application level. Probably, some service providers have already enjoyed reduced network infrastructure and operational costs by merging voice and data transport, but the majority may have failed to realize the significant cost, productivity, and service differentiation capabilities that converged, collaborative applications could bring. This elaborates mechanisms needed for a robust and globally interconnected network environment (including infrastructure, systems, processes, and people) in which data is shared timely and seamlessly among users, applications, and platforms. Such an environment enables substantially improved situational awareness and shortened decision-making cycles. Stepping ahead, our contribution discusses standards making application or service convergence a reality.  相似文献   
674.
A technique for selecting a rational variant of a multifunctional aircraft system using the analytic hierarchy process is proposed and a solution of a practical problem is presented.  相似文献   
675.
The historical development of terrestrial atmospheric electricity is described, from its beginnings with the first observations of the potential gradient to the global electric circuit model proposed by C.T.R. Wilson in the early 20th century. The properties of the terrestrial global circuit are summarised. Concepts originally needed to develop the idea of a global circuit are identified as “central tenets”, for example, the importance of radio science in establishing the conducting upper layer. The central tenets are distinguished from additional findings that merely corroborate, or are explained by, the global circuit model. Using this analysis it is possible to specify which observations are preferable for detecting global circuits in extraterrestrial atmospheres. Schumann resonances, the extremely low frequency signals generated by excitation of the surface-ionosphere cavity by electrical discharges, are identified as the most useful single measurement of electrical activity in a planetary atmosphere.  相似文献   
676.
The paper is related to specific emissions at frequency <3 MHz observed by the low altitude satellite DEMETER in relation with the thunderstorm activity. At its altitude (~700 km), the phenomena observed on the E-field and B-field spectrograms recorded by the satellite are mainly dominated by whistlers. Particular observations performed by DEMETER are reported. It concerns multiple hop whistlers and interaction between whistlers and lower hybrid noise. Two new phenomena discovered by the satellite are discussed. First, V-shaped emissions up to 20 kHz are observed at mid-latitude during night time. They are centered at the locations of intense thunderstorm activity. By comparison with VLF saucers previously observed by other satellites in the auroral zones it is hypothesized that the source region is located below the satellite and that the triggering mechanism is due to energetic electrons accelerated during sprite events. Second, emissions at frequency ~2 MHz are observed at the time of intense whistlers. These emissions are produced in the lower ionosphere in probable relation with Transient Luminous Events (TLEs).  相似文献   
677.
This describes a NOAA-14 spacecraft loss of control event and the lessons learned. The lessons learned are in two categories: contingency recovery operations; and on-orbit propulsion system isolation methods. The work is motivated in recognition of the effort of the NOAA off-line engineering support team and their NOAA civil servant mission leads and operations support staff.  相似文献   
678.
679.
Congress authorized NASA's Prometheus Project in February 2003, with the first Prometheus mission slated to explore the icy moons of Jupiter. The project had two major objectives: 1) to develop a nuclear reactor that would provide unprecedented levels of power and show that it could be processed safely and operated reliably in space for long-duration, deep-space exploration; and 2) to explore the three icy moons of Jupiter - Callisto, Ganymede, and Europa - and return science data that would meet the scientific goals as set forth in the Decadal Survey Report of the National Academy of Sciences. Early in project planning, it was determined that the development of the Prometheus nuclear-powered spaceship would be complex and require the intellectual knowledge residing at numerous organizations across the country. In addition, because of the complex nature of the project and the multiple partners, approaches beyond those successfully used to manage a typical JPL project would be needed. This describes the key experiences in managing Prometheus, which should prove useful for future projects of similar scope and magnitude.  相似文献   
680.
Network management is one of the key technologies needed to fulfill the requirements. In other words, a new paradigm for network management is also needed, in order to address the requirements arising both from the ATN side and the telecommunication side of the new telecommunication infrastructure. In particular, the new network management paradigm will incorporate the ATN management framework consisting of related standards, along with the telecommunication management framework, notably Telecommunication Management Network (TMN) standards from ITU-T.  相似文献   
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