421 research outputs found

    Home rule: the creation of local historic districts in the New Boston, 1953 to 1983

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    As large-scale, modernist urban renewal projects advanced following World War II, residents of Boston’s historic neighborhoods pushed back, asserting the value of the existing built environment and enlisting new strategies, like local historic districts, to mediate change. Over time, these defenders of traditional urbanism changed from relatively conventional 1950s home- and business-owners to more countercultural, back-to-the-city technocrats, the advance guard of a new middle class. Employing previously unexplored government archives and public documents, extensive contemporaneous newspaper reports, and interviews with current and former neighborhood activists, “Home Rule” analyzes historic districting as a social movement, tracing how adherents of this cause mobilized resources to effect the policy changes they sought. While the growth of the historic preservation movement in the interwar South has been well documented, the adoption of preservation planning techniques in the post-war North is less well studied. The first chapter investigates the effort to create the first historic district in the urban North on Beacon Hill, a campaign that took place against the backdrop of a destructive urban-renewal project in the nearby West End. A neighborhood association spearheaded the effort, carefully building support, consistent with the consensus culture of the 1950s. The chapter also examines the expansion of the district and challenges to its authority. The highly contested movement to designate the Back Bay occupies the second chapter, pitting a powerful mayor and his deep-pocketed allies determined to insert high-rise towers in a historically low-rise area against a large and well-heeled neighborhood association. The third chapter examines the drive to create a statutory Landmarks Commission to regulate historic resources citywide. The chapter also explores two attempts to designate historic districts after the creation of the new agency, one effort on Ashmont Hill that failed and another in West Back Bay that succeeded. The movement to designate three contiguous historic districts – the St. Botolph Street area, Bay Village, and the South End – constitutes the fourth and last chapter. These efforts exemplify the rediscovery of urban life by an educated, progressive middle class who negotiated with various ethnic and racial minorities, transformed the city, and reinvented urban renewal.2018-08-11T00:00:00

    Ionospheric calibration for single frequency altimeter measurements

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    This report investigates the potential of using Global Positioning System (GPS) data and a model of the ionosphere to supply a measure of the sub-satellite Total Electron Current (TEC) of the required accuracy (10 TECU rms) for the purpose of calibrating single frequency radar altimeter measurements. Since climatological (monthly mean) models are known to be in error by as much as 50 percent, this work focused on the Parameterized Real-Time Ionospheric Specification Model (PRISM) which has the capability to improve model accuracy by ingesting (adjusting to) in situ ionospheric measurements. A set of globally distributed TEC measurements were generated using GPS data and were used as input to improve the accuracy of the PRISM model. The adjusted PRISM TEC values were compared to TOPEX dual frequency TEC measurements (which are considered truth) for a number of TOPEX sub-satellite tracks. The adjusted PRISM values generally compared to the TOPEX measurements within the 10 TECU accuracy requirements when the sub-satellite track passed within 300 to 400 km of the GPS TEC data or when the track passed through a night time ionosphere. However, when the sub-satellite points were greater than 300 to 400 km away from the GPS TEC data or when a local noon ionosphere was sampled, the adjusted PRISM values generally differed by greater than 10 TECU rms with data excursions from the TOPEX TEC measurements of as much as 40 TECU (an 8 cm path delay error at K band). Therefore, it can be concluded from this analysis that an unrealistically large number of GPS stations would be needed to predict sub-satellite TEC at the 10 TECU level in the day time ionosphere using a model such as PRISM. However, a technique currently being studied at the Jet Propulsion Laboratory (JPL) may provide a means of supplying adequate TEC data to meet the 10 TECU ionospheric correction accuracy when using a realistic number of ionospheric stations. This method involves using global GPS TEC data to estimate a global grid of vertical ionospheric TEC as a function of time (i.e. every one half hour) in a sun-fixed longitude frame. Working in a sun-fixed longitude frame, one is not limited by the spatial decorrelation distance of the ionosphere, but instead is limited more by the temporal correlations of the ionosphere in the sun-fixed frame which are a smaller effect. It is the opinion of the authors that using the global sun-fixed TEC grid data, in particular, ingesting it into PRISM, offers the best possibility of meeting the 10 TECU ionospheric correction accuracy requirement, and should be the subject of further study

    Internal structures of electrons and photons: the concept of extended particles revisited

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    The theoretical foundations of quantum mechanics and de Broglie--Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of extended particles comply with a wave-equation. Including external potentials yields the Schrodinger equation, which, in this context, is arbitrary due to internal energy components. The statistical interpretation of wave functions in quantum theory as well as Heisenberg's uncertainty relations are shown to be an expression of this, fundamental, arbitrariness. Electrons and photons can be described by an identical formalism, providing formulations equivalent to the Maxwell equations. Electrostatic interactions justify the initial assumption of electron-wave stability: the stability of electron waves can be referred to vanishing intrinsic fields of interaction. The theory finally points out some fundamental difficulties for a fully covariant formulation of quantum electrodynamics, which seem to be related to the existing infinity problems in this field.Comment: 14 pages (RevTeX one column) and 1 figure (eps). For a full list of available papers see http://info.tuwien.ac.at/cms/wh

    Preface [to SEASAT II]

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    No abstract is available for this article

    Some aspects of simultaneously flying Topex Follow-On in a Topex orbit with Geosat Follow-On in a Geosat orbit

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    The advantages of having Geosat Follow-On in a Geosat orbit flying simultaneously with Topex Follow-On in a Topex/Poseidon orbit are examined. The orbits are evaluated using two criteria. The first is the acute crossover angle. This angle should be at least 40 degrees in order to accurately resolve the slope of sea level at crossover locations. The second is tidal aliasing. In order to solve for tides, the largest constituents should not be aliased to a frequency lower than two cycles/year and should be at least one cycle discrete from one another and from exactly two cycles/year over the mission life. The results show that TFO and GFO in these orbits complement each other. Both satellites have large crossover angles over a wide latitude range. In addition, the Topex orbit has good aliasing characteristics for the M2 and P1 tides for which the Geosat orbit has difficulty

    Remembering Harry Pratter (1917-2002)

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    At this year\u27s annual Alumni Weekend, colleagues, family, friends, and former students of the inimitable Professor Harry Pratter, who died in March 2002, gathered to share their recollections of his life and career. Pratter, who was born in the Ukraine and emigrated to the United States as a child, began teaching at the Law School in 1950, after earning his JD from the University of Chicago. He taught many different subjects, including Commercial Law, Negotiable Instruments, Conflicts of Law, Contracts, Torts, and Family Law. But more fundamentally, he taught life, according to Professor Fred Aman, longtime dean of the school. For Harry, says Aman, there was no such thing as just a legal problem. There were only human problems with which the law must deal. The following remembrances were presented by Pratter\u27s former students

    Remembering Harry Pratter (1917-2002)

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    At this year\u27s annual Alumni Weekend, colleagues, family, friends, and former students of the inimitable Professor Harry Pratter, who died in March 2002, gathered to share their recollections of his life and career. Pratter, who was born in the Ukraine and emigrated to the United States as a child, began teaching at the Law School in 1950, after earning his JD from the University of Chicago. He taught many different subjects, including Commercial Law, Negotiable Instruments, Conflicts of Law, Contracts, Torts, and Family Law. But more fundamentally, he taught life, according to Professor Fred Aman, longtime dean of the school. For Harry, says Aman, there was no such thing as just a legal problem. There were only human problems with which the law must deal. The following remembrances were presented by Pratter\u27s former students

    Altimetric system: Earth observing system. Volume 2h: Panel report

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    A rationale and recommendations for planning, implementing, and operating an altimetric system aboard the Earth observing system (Eos) spacecraft is provided. In keeping with the recommendations of the Eos Science and Mission Requirements Working Group, a complete altimetric system is defined that is capable of perpetuating the data set to be derived from TOPEX/Poseidon, enabling key scientific questions to be addressed. Since the scientific utility and technical maturity of spaceborne radar altimeters is well documented, the discussion is limited to highlighting those Eos-specific considerations that materially impact upon radar altimetric measurements

    Correction of Single Frequency Altimeter Measurements for Ionosphere Delay

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    This study is a preliminary analysis of the accuracy of various ionosphere models to correct single frequency altimeter height measurements for Ionospheric path delay. In particular, research focused on adjusting empirical and parameterized ionosphere models in the parameterized real-time ionospheric specification model (PRISM) 1.2 using total electron content (TEC) data from the global positioning system (GPS). The types of GPS data used to adjust PRISM included GPS line-of-sight (LOS) TEC data mapped to the vertical, and a grid of GPS derived TEC data in a sun-fixed longitude frame. The adjusted PRISM TEC values, as well as predictions by IRI-90, a climatotogical model, were compared to TOPEX/Poseidon (T/P) TEC measurements from the dual-frequency altimeter for a number of T/P tracks. When adjusted with GPS LOS data, the PRISM empirical model predicted TEC over 24 1 h data sets for a given local time to with in a global error of 8.60 TECU rms during a midnight centered ionosphere and 9.74 TECU rms during a noon centered ionosphere. Using GPS derived sun-fixed TEC data, the PRISM parameterized model predicted TEC within an error of 8.47 TECU rms centered at midnight and 12.83 TECU rms centered at noon. From these best results, it is clear that the proposed requirement of 3-4 TECU global rms for TOPEX/Poseidon Follow-On will be very difficult to meet, even with a substantial increase in the number of GPS ground stations, with any realizable combination of the aforementioned models or data assimilation schemes

    Ionospheric calibration for single frequency altimeter measurements

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    This study is a preliminary analysis of the effectiveness (in terms of altimeter calibration accuracy) of various ionosphere models and the Global Positioning System (GPS) to calibrate single frequency altimeter height measurements for ionospheric path delay. In particular, the research focused on ingesting GPS Total Electron Content (TEC) data into the physical Parameterized Real-Time Ionospheric Specification Model (PRISM), which estimates the composition of the ionosphere using independent empirical and physical models and has the capability of adjusting to additional ionospheric measurements. Two types of GPS data were used to adjust the PRISM model: GPS receiver station data mapped from line-of-sight observations to the vertical at the point of interest and a grid map (generated at the Jet Propulsion Laboratory) of GPS derived TEC in a sun-fixed longitude frame. The adjusted PRISM TEC values, as well as predictions by the International Reference Ionosphere (IRI-90), a climatological (monthly mean) model of the ionosphere, were compared to TOPEX dual-frequency TEC measurements (considered as truth) for a number of TOPEX sub-satellite tracks. For a 13.6 GHz altimeter, a Total Electron Content (TEC) of 1 TECU 10(exp 16) electrons/sq m corresponds to approximately 0.218 centimeters of range delay. A maximum expected TEC (at solar maximum or during solar storms) of 10(exp 18) electrons/sq m will create 22 centimeters of range delay. Compared with the TOPEX data, the PRISM predictions were generally accurate within the TECU when the sub-satellite track of interest passed within 300 to 400 km of the GPS TEC data or when the track passed through a night-time ionosphere. If neither was the case, in particular if the track passed through a local noon ionosphere, the PRISM values differed by more than 10 TECU and by as much as 40 TECU. The IRI-90 model, with no current ability to unseat GPS data, predicted TEC to a slightly higher error of 12 TECU. The performance of PRISM is very promising for predicting TEC and will prove useful for calibrating single frequency altimeter height measurements for ionospheric path delay. When adjusted to the GPS line-of-sight data the PRISM URSI empirical model predicted TEC over a day's period to within a global error of 8.60 TECU rms during a nighttime ionosphere and 9.74 TECU rms during the day. When adjusted to the GPS derived TEC grid, the PRISM parametrized model predicted TEC to within an error of 8.47 TECU rms for a nighttime ionosphere and 12.83 TECU rms during the day. However, the grid cannot be considered globally due to the lack of sufficient numbers of GPS stations and large latitude gaps in GPS data. It is the opinion of the authors that using the PRISM model and adjusting to the global sun-fixed TEC grid regenerated with a localized weighted interpolation offers the best possibility of meeting the 10 TECU global rms (or 2 cm at 13.6 GHz) ionosphere range correction accuracy requirement of TOPEX/Poseidon and should be the subject of further study. However, it is clear that the anticipated requirement of 34 TECU global rms for TOPEX/Poseidon Follow-On (corresponding to the TOPEX/Poseidon performance) can not be met with any realizable combination of existing models and data assimilation schemes
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