1,395 research outputs found

    Continuing the Dialogue: Augustana College

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    Interactive Control of a Parallel Simulation from a Remote Graphics Workstation

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    Modern military commanders are faced with an overwhelming amount of intelligence data concerning the disposition of engaging forces, The sheer volume of data produced for a single planning scenario is an obstacle to the user as well as the computer. Today’s commander requires a real-time, three- dimensional representation of the battlefield in order to assimilate the data for the management of a conflict. Parallel computation is required to complete the processing of this information in a timely manner. A network protocol is required to link the interface with the parallel simulation. The of this study is to improve user interaction through graphical representation of a parallel simulation. Each portion of the system, the user interface, the simulation, and the network are discussed in this research. The concentration of the research deals with the parallel simulations ability to accept and act upon user input without corrupting the integrity of its execution. This includes the ability to receive and act upon a rewind or rollback command from the user. Effectively, this command halts the parallel execution and rewinds is back for restart at a previous state and time. Solutions to limitations in a conservative parallel simulation are developed and presented. Specifically, the ability of the parallel simulation to periodically save its state, and synchronize its separate logical processes for user input. All of the requirements for the users control commands and the effect of these requirements upon the entire system are developed and demonstrated. This research provides an increased capability to assist in battlefield management and critical decision making processes

    Investigation of fast initialization of spacecraft bubble memory systems

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    Bubble domain technology offers significant improvement in reliability and functionality for spacecraft onboard memory applications. In considering potential memory systems organizations, minimization of power in high capacity bubble memory systems necessitates the activation of only the desired portions of the memory. In power strobing arbitrary memory segments, a capability of fast turn on is required. Bubble device architectures, which provide redundant loop coding in the bubble devices, limit the initialization speed. Alternate initialization techniques are investigated to overcome this design limitation. An initialization technique using a small amount of external storage is demonstrated

    Dual frequency (20.0-19.9 kHz) VLF data

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    Data are presented from 24 months of operation of radio station WWVL. Daily measurements of the 20.0 kHz and 20.0/19.9 kHz signal phase angles corrected in accordance with the NBS measurements are presented in tabular form. The 20.0/19.9 kHz data is a function of the phase angle of the 100 Hz information inherent in the 20.0/19.9 transmissions. This data can be used to resolve the 50 microsecond ambiguity inherent in 20.0 kHz single frequency transmissions

    Prerequisites for Successful Fiscal Reform: Some Preliminary Results

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    Journal of Public Budgeting, Accounting and Financial Management, Winter 1998.Refereed Journal ArticleThis paper examines whether any relationship exists between success or failure of policy reform on the one hand, and various political/economic conditions in place at the time of reform on the other. Nineteen countries were scored using three financial variables to measure the degree of success or failure of the reform. The independent variables were country scores for ten different economic and political conditions. The independent variables were used to try and predict a priori which of the nineteen countries would succeed and which would fail. Eighteen of the nineteen countries were correctly placed into their respective success group. However only three of the ten conditions appeared important in predicting success: a visionary leader, a crisis, and a comprehensive program. Other writers have suggested different sets of predicting variables

    A Flattened Protostellar Envelope in Absorption around L1157

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    Deep Spitzer IRAC images of L1157 reveal many of the details of the outflow and the circumstellar environment of this Class 0 protostar. In IRAC band 4, 8 microns, there is a flattened structure seen in absorption against the background emission. The structure is perpendicular to the outflow and is extended to a diameter of 2 arcminutes. This structure is the first clear detection of a flattened circumstellar envelope or pseudo-disk around a Class 0 protostar. Such a flattened morphology is an expected outcome for many collapse theories that include magnetic fields or rotation. We construct an extinction model for a power-law density profile, but we do not constrain the density power-law index.Comment: ApJL accepte

    1.3 mm Polarized emission in the circumstellar disk of a massive protostar

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    We present the first resolved observations of the 1.3 mm polarized emission from the disk-like structure surrounding the high-mass protostar Cepheus A HW2. These CARMA data partially resolve the dust polarization, suggesting a uniform morphology of polarization vectors with an average position angle of 57° ± 6° and an average polarization fraction of 2.0% ± 0.4%. The distribution of the polarization vectors can be attributed to (1) the direct emission of magnetically aligned grains of dust by a uniform magnetic field, or (2) the pattern produced by the scattering of an inclined disk. We show that both models can explain the observations, and perhaps a combination of the two mechanisms produces the polarized emission. A third model including a toroidal magnetic field does not match the observations. Assuming scattering is the polarization mechanism, these observations suggest that during the first few 104 years of high-mass star formation, grain sizes can grow from1 mm to several 10s μm.Fil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; ArgentinaFil: Stephens, I. W.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos. Boston University; Estados Unidos. University of Illinois; Estados UnidosFil: Girart, J. M.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos. Institut de Ciències de l’Espai; EspañaFil: Looney, L.. University of Illinois; Estados UnidosFil: Curiel, S.. Universidad Nacional Autónoma de México; MéxicoFil: Segura Cox, D.. University of Illinois; Estados UnidosFil: Eswaraiah, C.. National Tsing Hua University; República de ChinaFil: Lai, S. P.. National Tsing Hua University; República de Chin
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