89 research outputs found
Media education in youth media: specific methods of organizing the educational process
No full textThe article raises the issue of enhancing efficiency of media-education activity through youth involvement in creating various media. Author describes the development of amateur children and youth editions in Russia, determined by the formation of the information society. Particular attention is paid to the problem of improving the media literacy of young people.
The author presents the experience of the editorial board of the regional children’s and youth newspaper Sami (Russia, Altai Region), which authors are children, so the editorial board carry out educational functions. The experimental approach described in the article used traditional forms of editorial work as forms of educational activity. The organization of such forms of work as an editorial meeting and a press conference is described in detail. It is told what educational problems they solve. The article presents the technology developed by the professor of the Altai State Pedagogical University Ivan Shalaev and gained recognition in Russia. This is a motivational program-and- goal-oriented approach, the key concept of which is the formation of a motivational complex for students. Ivan Shalaev developed a typology of stimulus situations that contribute to the formation of a motivational complex. The author of the article considers the technology of modeling stimulus situations in the conditions of the editorial board of juvenile media, describes the results of their use.
The author proves that using the motivational program-and-goal-oriented approach enhances the efficiency of media education and teaching teenagers basic journalism skills
Loran phase codes, revisited
No full textThe United States has a significant, strategic investment in the Loran system in its tower and monitor locations nationwide. Furthermore, many in the US and Europe have recognized that Loran (actually a developing modernized version called eLoran) is the best choice for a backup position, navigation, and timing (PNT) system to the global positioning system (GPS) in that it is not subject to the same vulnerabilities and failure modes. The current Loran-C signal, repeated groups of teardrop shaped pulses modulated to 100 kHz, has been operated by the U.S. Coast Guard since 1957. While recent years have brought numerous improvements to the Loran system, these have been technological upgrades to improve efficiency and reliability of the transmitter equipment; the details of the system\u27s signaling have not changed and the system still operates essentially as it was designed and implemented 50 years ago. The design decisions made then were based upon the technology available at that time; the fact that the system is still operational and viable today is a tribute to the system design. However, now, with advances in technology, there are changes that could be made to the system that could improve performance. A natural question then, that should be part of the development of eLoran, is: How should the system be configured to best serve PNT users given today\u27s technologies? In a paper at PLANS 2006, these authors began this discussion by re-opening some of the degrees of freedom in the system\u27s design process. While certain hard constraints were kept (tower locations, power levels, spectrum, and it being an 8-pulse per group ranging system), that paper investigated the impact of several implementation options on navigation accuracy: time-of-transmission control of the transmitters, single-rating all stations, and chain/GRI realignment. The conclusion in that paper was that all three changes yielded a net gain in Loran navigation accuracy. This current paper continues the discussion by investigating possible changes to the Loran phase codes, and the potential improvements that such changes could provide. (The term phase code refers to a multiplier of ±1 on the envelope of each individual Loran pulse; the sequence of signs repeats every two groups or phase code interval. ) Currently, all Master signals use one specific phase code and all Secondary signals use another. The phase codes now in use allow for cancellation of sky wave interference (beyond 1 msec delay, that is) and for discrimination between Master and Secondary stations, an important consideration for legacy Loran receiver technology. The goal in this paper is to open up the discussion of phase code selection. Two importantissues considered are:•The codes themselves - could redesigned phase codes still provide sufficient sky wave protection, yet yield improved cross rate interference rejection?•The allocation of the codes - currently, all Secondaries share a common phase code (Master signals have a different code). Could different stations have different phase codes (e.g. implementing a form of code division multiplexing)? © 2008 IEEE
Airframe effects on Loran H-field antenna performance
No full textThe 2001 Volpe National Transportation Systems Center report on GPS vulnerabilities identified Loran-C as one possible backup system for GPS. The Federal Aviation Administration (FAA) observed in its recently completed Navigation and Landing Transition Study that Loran-C, as an independent radio navigation system, is theoretically the best backup for GPS; however, this study also observed that Loran-C\u27s potential benefits hinge upon the level of position accuracy actually realized (as measured by the 2 drms error radius). For aviation applications this is the ability to support non-precision approach (NPA) at a Required Navigation Performance (RNP) of 0.3 which equates to a 2 drms error of 309 meters. The recently released report of the DOT Radionavigation Task Force recommended to complete the evaluation of enhanced Loran to validate the expectation that it will provide the performance to support aviation NPA and maritime HEA operations. To meet this need, the FAA is currently leading a team consisting of members from industry, government, and academia to provide guidance to the policy makers in their evaluation of the future of enhanced Loran (eLoran) in the United States. Through FAA sponsoring, the U.S. Coast Guard Academy (USCGA) is responsible for conducting some of the tests and evaluations to help determine whether eLoran can provide the accuracy, availability, integrity, and continuity to meet these requirements. One area of importance that has been under investigation has been the use of H-field antennas to receive the Loran signal (the times of arrivals of the signals, or TOAs, are used in the navigation position solution). H-field antennas provide better performance than E-field antennas (the usual maritime antenna) in the presence of precipitation static, which is a common problem on aircraft. However, in the past, our research has shown that H-field antennas suffered from loop coupling and other effects that led to variations, or errors, in the received TOAs as a function of bearing to the Loran station. New antennas are improved over older models; however, the installation of the antenna on the airframe changes the performance from that of the antenna alone. A necessary task to certify Loran for NPA is bounding the effects of those error sources that cannot be eliminated. The USCG Academy and Alion in partnership with the FAA Technical Center have been conducting tests on H-field antennas both on and off the Convair 580 in order to characterize the impact the aircraft has on the antenna performance. This paper presents the results of this testing and makes an assessment as to the error bounds required for H-field antennas on aircraft
Performance trials of an Integrated loran/GPS/IMU navigation system, part i
No full textThe Federal Aviation Administration (FAA) is currently leading a team consisting of members from Industry, Government, and Academia to provide guidance to the policy makers in their evaluation of the future of Loran-C in the United States. In a recently completed Navigation Transition Study, the FAA concluded that Loran-C, as an independent radionavigation (RNAV) system, is theoretically the best backup for the Global Positioning System (GPS). However, in order for Loran-C to be considered a viable back-up system to GPS, it must be able to meet the requirements for non-precision approaches (NPA\u27s) for the aviation community, and the Harbor Entrance and Approach (HEA) requirements for the maritime community. Through FAA sponsoring, the U.S. Coast Guard Academy (USCGA) is responsible for conducting some of the tests and evaluations to help determine whether Loran can provide the accuracy, availability, integrity, and continuity to meet these requirements. A major part of assessing the suitability of Loran is in understanding the nature of Loran ground wave propagation over paths of varying conductivities and terrain. Propagation time adjustments, called additional secondary factors (ASFs), are used to adjust receiver times of arrival (TOAs) to account for propagation over non-seawater path(s). These ASFs vary both spatially and temporally, and unless understood and/or modeled, we lose accuracy and may not be able to guarantee a hazardously misleading information (HMI) probability of less than 1×10-7. The Coast Guard Academy has been conducting a series of tests on a new integrated Loran/GPS/IMU receiver in the Thames River. This receiver integrates IMU information (velocity and acceleration) and ASF data from a stored grid into the Loran position solution to improve the accuracy and consistency of the resulting position. The density of the ASF grid used is based upon our previous study (ION AM June 2004); points in between the grid values are calculated by the receiver using a linear interpolation. The GPS information (position, time) is used to measure the ASF values in real-time to track deviations from the stored ASF grid. These grid differences are used to correct the grid values in the absence of a local ASF monitor station. Performance of the receiver using different ASF grids and interpolation techniques and corrected using the real-time calculated grid differences is shown. Finally, how all of these efforts lead towards meeting the accuracy requirements is shown
Can LORAN meet GPS backup requirements?
No full textThe use of Loran-C as the best backup system to Global Positioning System (GPS) was discussed. It was observed that Loran-C\u27s potential benefits hinge upon the level of position accuracy actually realized as measured by the 2 drms error radius. A significant factor limiting the accuracy of Loran system was the spatial and temporal variation in the times of arrival (TOA) observed by the receiver. The simulation efforts have shown that the Loran system is capable of meeting the aviation and maritime accuracy requirements
Software defined radio for HA-NDGPS performance improvements
No full textThe Next Generation High-Speed Rail Program is a key element in the Department of Transportation\u27s overall program to encourage the development of higher speed rail in the United States. The main focus is on implementing high-speed rail service in selected congested corridors to achieve a more balanced intermodal transportation system. The Program supports the advancement of high-speed rail, particularly on existing infrastructure, by improving, adapting, and demonstrating potentially more cost-effective technologies which could have wide application in U.S. corridors. Up until 2007 the Federal Railroad Administration was the lead agency of nine federal agencies working to develop the Nationwide Differential Global Positioning System. NDGPS is needed for Positive Train Control and is also an enabling technology for automated railroad surveying systems and accurate rail defect detection. FRA and the other agencies have been exploring new signals that could be added to the NDGPS system to improve the accuracy, integrity, anti-jam capability and overall signal robustness. The development and use of High Accuracy Nationwide DGPS (HA-NDGPS) was identified by the Federal Railroad Administration (FRA) as a necessary capability for positive train control (PTC) and for automated rail survey. Currently the only HA-NDGPS receiver in existence is a modified DGPS beacon receiver, of which only a few prototypes exist. There are also concerns about the receiver\u27s ability to function in the noise environment found on locomotives. These receivers also do not have the ability to collect raw signal data which can be used as a tool to post process and characterize signal quality. Under contract to the FRA, Alion Science and Technology has developed a software-defined receiver for HA-NDGPS experimentation and testing. This Digital Signal Processing (DSP) receiver is a combination of COTS hardware including: analog RF front-end gain and filtering; high-speed A/D data acquisition, and a standard laptop computer running C++ and MatLab ™ receiver code. This new advanced capability receiver has been used to establish a performance baseline of the current HA-NDGPS system. Specifically, in this paper we will report upon the software receiver design and development, the lab simulator built to test the receiver, the performance curves (BER vs SNR) from both lab and field testing, and the characterization and mitigation of the noise environment found on typical locomotives based upon testing in Omaha, NE and in Lancaster, PA
An Evaluation of eLoran as a Backup to GPS
No full textIn 2001, the Volpe National Transportation Systems Center completed an evaluation of the Global Positioning System (GPS) vulnerabilities and the potential impacts to transportation systems in the United States. One of the recommendations of this study was for the operation of backup system(s) to GPS; Loran C, which has been operated by the U.S. Coast Guard for the past 40 years, was identified as one possible backup system. The Federal Aviation Administration (FAA) has been leading a team consisting of members from industry, government, and academia to evaluate the future of Loran-C in the United States. In a recently completed Navigation Transition Study, the FAA concluded that Loran-C, as an independent radionavigation system, is theoretically the best backup for the GPS; however, in order for Loran-C to be considered a viable back-up system to GPS, it must be able to meet the requirements of non-precision approach (NPA) for the aviation community and the Harbor Entrance and Approach (HEA) requirements for the maritime community. The accuracy requirements for Loran to be used as a backup system are 307m for NPA and 20m for HEA. In addition, there are integrity, availability, and continuity requirements. The current Loran system of 24 Stations provides a stated absolute accuracy in navigation position of only 0.25 NM; however, enhanced Loran or eLoran has the capability of meeting the stringent requirements for NPA and HEA. In order to meet the accuracy requirements user receivers must use Additional Secondary Factors (ASFs) in calculating the user position. ASFs are propagation time adjustments that are subtracted from the receiver\u27s times of arrival (TOAs) to account for propagation over non-seawater paths. These ASFs vary both spatially and temporally and both types of variations need to be accounted for to meet the accuracy targets. The current approaches to meeting the needs of the aviation and maritime communities are slightly different. For maritime navigation, the spatial variations will be accounted for through the use of a grid of ASF values that is known by the receiver a priori. As one component of the eLoran system, a reference station located nearby the harbor will be used to estimate the temporal changes in the ASFs relative to the published spatial grid; these differences will be broadcast using the Loran Data Channel (9th pulse) to the user receiver. This general method to HEA navigation was discussed by the authors in 2003 (ION AM 2003). More recently (ION GNSS 2006) we developed a technique to process survey data into a harbor grid. For the aviation community the approach is to measure and publish a set of ASF values for each airport. These airport ASFs will be adjusted to be in the middle of the seasonal variation in order to minimize the maximum error. This approach has been discussed by the authors most recently in papers presented in 2005 (ILA 34) and 2006 (ION NTM 2006). In this paper we will show results from both flight tests at various airports around the U.S. and maritime tests in the Thames River in CT. These results demonstrate the ability of eLoran to meet the accuracy requirements for both NPA and HEA using the ASF methods we have proposed. © 2007 IEEE
Exciton luminescence suppression in BaF2–LaF3 solid solutionsDue to circumstances beyond the Publisher's control, this article appears in print without author corrections
No full textLow-dose anticoagulation with rivaroxaban in the long-term prophylaxis of cardiovascular complications in patients with acute coronary syndrome
No full textThe ongoing search of optimal antithrombotic drug maintenance of patients with acute coronary syndrome [ACS] after performing intracoronary interventions is an obvious trend of modern cardiology. In the publication, the opportunities of new oral anticoagulants in long-term prophylaxis of cardiovascular complications after ACS are shown from the standpoint of evidence-based cardiology. The results of randomized study ATLAS ACS 2-TIMI 51, which evaluated the effectiveness and safety of low-dose anticoagulation with rivaroxaban for patients with ACS in addition to dual antiplatelet therapy, are studied in details. The author makes the conclusion that with suitable selection of “candidates" the low-dose anticoagulation therapy with rivaroxaban can represent a new strategy in treating patients with recent ACS.Продолжающийся поиск оптимального лекарственного антитромботического сопровождения больных острым коронарным синдромом [ОКС] после выполнения интракоронарных вмешательств - очевидный тренд современной кардиологии. В публикации с позиций доказательной кардиологии освещаются возможности новых оральных антикоагулянтов в долгосрочной профилактике сердечно-сосудистых осложнений после перенесенного ОКС. Детально рассматриваются результаты рандомизированного исследования ATLAS ACS 2-TIMI 51, оценивавшего эффективность и безопасность низкодозовой антикоагуляции ривароксабаном у больных ОКС в дополнение к двойной антитромбоцитарной терапии. Автором делается заключение, что при условии адекватного отбора «кандидатов» низкодозовая антикоагулянтная терапия ривароксабаном может представлять новую стратегию лечения больных с недавно перенесенным ОКС
Laminar-turbulent transition in the vicinity of blunt leading edge of flat delta wing in hypersonic flow
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