A study of a space communication system for the control and monitoring of the electric distribution system. Volume 1: Summary

It is technically feasible to design a satellite communication system to serve the United States electric utility industry's needs relative to load management, real-time operations management, remote meter reading, and to determine the costs of various elements of the system. A definition of distribution control and monitoring functions is given. Associated communications traffic is quantified. A baseline conceptual design in terms of operating capability and equipment is described, important factors to be considered in designing a system are examined, and preliminary cost data are provided. Factors associated with implementation are discussed and conclusions and recommendations are listed

Secure voice for mobile satellite applications

The initial system studies are described which were performed at JPL on secure voice for mobile satellite applications. Some options are examined for adapting existing Secure Telephone Unit III (STU-III) secure telephone equipment for use over a digital mobile satellite link, as well as for the evolution of a dedicated secure voice mobile earth terminal (MET). The work has included some lab and field testing of prototype equipment. The work is part of an ongoing study at JPL for the National Communications System (NCS) on the use of mobile satellites for emergency communications. The purpose of the overall task is to identify and enable the technologies which will allow the NCS to use mobile satellite services for its National Security Emergency Preparedness (NSEP) communications needs. Various other government agencies will also contribute to a mobile satellite user base, and for some of these, secure communications will be an essential feature

A study of a space communication system for the control and monitoring of the electric distribution system. Volume 2: Supporting data and analyses

It is technically feasible to design a satellite communication system to serve the United States electric utility industry's needs relative to load management, real-time operations management, remote meter reading and to determine the costs of various elements of the system. The functions associated with distribution automation and control and communication system requirements are defined. Factors related to formulating viable communication concepts, the relationship of various design factors to utility operating practices, and the results of the cost analysis are discussed The system concept and several ways in which the concept could be integrated into the utility industry are described

Satellite and terrestrial narrow-band propagation measurements at 2.05 GHz

A series of satellite and terrestrial propagation measurements were conducted on 15 and 16 Dec. 1994 in the vicinity of the Jet Propulsion Laboratory (JPL), Pasadena, California, in support of the VOA/JPL DBS-Radio Program. The reason for including terrestrial measurements was the possible use of terrestrial boosters to improve reception in some satellite digital audio broadcasting system service areas. The signal sources used were the NASA TDRS satellite located at 171 degrees West and a terrestrial transmitter located on a high point on JPL property. Both signals were unmodulated carriers near 2.05 GHz, spaced a few kHz apart so that both could be received simultaneously by a single receiver. An unmodulated signal was used in order to maximize the dynamic range of the signal strength measurement. A range of greater than 35 dB was achieved with the satellite signal, and over 50 dB was achieved with the terrestrial signal measurements. Three test courses were used to conduct the measurements: (1) a 33 km round trip drive from JPL through Pasadena was used to remeasure the propagation of the satellite signal over the path previously used in DBS-Radio experiments in mid 1994. A shortened portion of this test course, approximately 20 km, was used to measure the satellite and terrestrial signals simultaneously; (2) a 9 km round trip drive through JPL property, going behind buildings and other obstacles, was used to measure the satellite and terrestrial signals simultaneously; and (3) a path through one of the buildings at JPL, hand carrying the receiver, was also used to measure the satellite and terrestrial signals simultaneously

TO STAY OR NOT TO STAY: THAT IS A QUESTION

Emigration and immigration, particularly of young individuals, raise social, economic, and cultural problems for both the recipient and donor countries. Substantial fluctuations in these rates make coherent adjustment and planning for the resulting social processes at best difficult, at worst ineffective. We have undertaken a study of the behavior and motivation of university students as they enter the university educational system and begin their studies with an aim to provide a measure of predictability in this phenomenon. To identify important factors which influence a young person's choice between continuing studies in a native university and a foreign one we have carried out a longitudinal study of about fifty Lithuanian students at three time instances: At t0, the time they choose between emigration or staying in their home country for their university education; at t1, soon after they arrive and first encounter their chosen environment; at t2, some six months or so after their direct experience of their chosen environment. The investigation was carried out with respondents drawn from universities in Lithuania and Great Britain. The information was collected through in-depth interviews using ethnographic techniques, initiated with a questionnaire designed to identify some four hundred binary values but allowing additional exploration of naturally arising motivational factors

TO STAY OR NOT TO STAY: THAT IS A QUESTION

Emigration and immigration, particularly of young individuals, raise social, economic, and cultural problems for both the recipient and donor countries. Substantial fluctuations in these rates make coherent adjustment and planning for the resulting social processes at best difficult, at worst ineffective. We have undertaken a study of the behavior and motivation of university students as they enter the university educational system and begin their studies with an aim to provide a measure of predictability in this phenomenon. To identify important factors which influence a young person's choice between continuing studies in a native university and a foreign one we have carried out a longitudinal study of about fifty Lithuanian students at three time instances: At t0, the time they choose between emigration or staying in their home country for their university education; at t1, soon after they arrive and first encounter their chosen environment; at t2, some six months or so after their direct experience of their chosen environment. The investigation was carried out with respondents drawn from universities in Lithuania and Great Britain. The information was collected through in-depth interviews using ethnographic techniques, initiated with a questionnaire designed to identify some four hundred binary values but allowing additional exploration of naturally arising motivational factors

Benchmarking Study of Maintenance Performance Monitoring Practices

This Report summarizes the results of a research carried out in the year 2007 under the SONIS (Safety of Nuclear Installations) programme for 2007, Task 1.1.1, Maintenance effectiveness indicators and risk monitors. The research was based on the survey of the experience of European nuclear utilities in the use of maintenance performance indicators at selected European nuclear utilities. The survey results proved the validity of the specific maintenance performance indicators selected for the maintenance performance monitoring framework proposed by IE/JRC and published in the EU Report 22602. The obtained results provide good basis for further development and implementation of the proposed maintenance monitoring system. The analysis of the survey results revealed additional maintenance aspects critical to the effectiveness of maintenance programme. All these topics will be carefully analysed in the next steps of the research in connection to their coverage in the maintenance monitoring system and identification of critical items that could be subject for the further activities in the SONIS Research program.JRC.F.5-Nuclear operation safet

Coral Populations and Growth Patterns: Responses to Sedimentation and Turbidity Associated with Dredging

Analysis of coral growth patterns and populations in Bermuda reveals that living coral abundance on the reefs of Castle Harbor, a location where extensive dredging occurred during 1941- 1943, is much reduced in comparison to external North-South reefs. Dead corals, sampled in the harbor, have skeletal patterns of growth which are similar and which show a marked decline in growth for several years prior to death. For the brain coral genus Diploria, both D. strigosa and D. labyrinthiformis are fairly evenly represented on contemporary North-South reefs and in the assemblages of dead corals from Castle Harbor, while D. labyrinthiformis, a species demonstrably more capable of rejecting accumulated sediment, is the predominant living form inside the harbor. Age distributions of Castle Harbor living corals exhibit no members older than approximately 60 years and show abruptly decreasing numbers of individuals in the older age classes. The North-South living and Castle Harbor dead corals show a longevity of at least 250 years and a gradual decrease in the numbers of individuals from younger to older age classes. This evidence, coupled with information on the effects of sedimentation on corals, suggests that the process of dredging and its after effects created catastrophically detrimental conditions for the Castle Harbor coral population and produced mass coral mortality

Climatic Implications of Barbados Coral Growth

Results from a coral growth band analysis utilizing samples of M. annularis from the Recent Barbados reef and from three fossil raised reefs (Barbados I, II, and III dated at 82,000, 105,000, and 125,000 yrs. B.P.) indicate that in the Barbados II collection both average band width and variability were lower than in the other samples. We suggest the climate during formation of the 105,000 yrs. B.P. reef was significantly different than that of the present