2,667 research outputs found

    Integrated component-based computer design modeling system : the implications of the representation of control parameters on the design process

    Get PDF
    The design process is dependent on a clear order of integrating and managing all of the control parameters that impact on a building\u27s design. All component elements of a building must be defined by their: Physical and functional relations; Quantitative and calculable properties; Component and/or system functions. This requires a means of representation to depict a model of a building that can be viewed and interpreted by a variety of interested parties. These parties need different types of representation to address their individual control parameters, as each component instance has specific implications on all of the control parameters. Representations are prepared for periodic design review either manually through hand-drawn graphics and handcrafted models; or with the aid of computer aided design programs. Computer programs can profoundly increase the speed and accuracy of the process\u27, as well as provide a level of integration, graphic representation and simulation, untenable through a manual process. By maintaining a single control model in an Integrated Component-based Computer Design Modeling System (ICCDMS), interested parties could access the design model at any point during the process. Each party could either: 1. Analyze individual components, or constraints of the model, for interferences against parameters within that party\u27s control; or 2. Explore design alternatives to modify the model, and verify the integration of the components or functions, within the design model, as allowable in relation to other control parameters

    Mass extinctions: Persistent problems and new directions

    Get PDF
    Few contest that mass extinctions have punctuated the history of life, or that those events were so pervasive environmentally, taxonomically, and geographically that physical forcing factors were probably involved. However, consensus remains elusive on the nature of those factors, and on how a given perturbation - impact, volcanism, sea-level change, or ocean anoxic event - could actually generate the observed intensity and selectivity of biotic losses. At least two basic problems underlie these long-standing disagreements: difficulties in resolving the fine details of taxon ranges and abundances immediately prior to and after an extinction boundary and the scarcity of simple, unitary cause-and-effect relations in complex biological systems

    Software for Data Acquisition AMC Module with PCI Express Interface

    Get PDF
    Free Electron Laser in Hamburg (FLASH) and XRay Free Electron Laser (XFEL) are linear accelerators that require a complex and accurate Low Level Radio Frequency (LLRF) control system. Currently working systems are based on aged Versa Module Eurocard (VME) architecture. One of the alternatives for the VME bus is the Advanced Telecommunications and Computing Architecture (ATCA) standard. The ATCA based LLRF controller mainly consists of a few ATCA carrier boards and several Advanced Mezzanine Cards (AMC). AMC modules are available in variety of functions such as: ADC, DAC, data storage, data links and even CPU cards. This paper focuses on the software that allows user to collect and plot the data from commercially available TAMC900 board

    Correlated radial velocity and X-ray variations in HD 154791/4U 1700+24

    Get PDF
    We present evidence for approximately 400-d variations in the radial velocity of HD 154791 (V934 Her), the suggested optical counterpart of 4U 1700+24. The variations are correlated with the previously reported approximately 400 d variations in the X-ray flux of 4U 1700+24, which supports the association of these two objects, as well as the identification of this system as the second known X-ray binary in which a neutron star accretes from the wind of a red giant. The HD 154791 radial velocity variations can be fit with an eccentric orbit with period 404 +/- 3 d, amplitude K=0.75 +/- 0.12 km/s and eccentricity e=0.26 +/- 0.15. There are also indications of variations on longer time scales >~ 2000 d. We have re-examined all available ASM data following an unusually large X-ray outburst in 1997-98, and confirm that the 1-d averaged 2-10 keV X-ray flux from 4U 1700+24 is modulated with a period of 400 +/- 20 d. The mean profile of the persistent X-ray variations was approximately sinusoidal, with an amplitude of 0.108 +/- 0.012 ASM count/s (corresponding to 31% rms). The epoch of X-ray maximum was approximately 40 d after the time of periastron according to the eccentric orbital fit. If the 400 d oscillations from HD 154791/4U 1700+24 are due to orbital motion, then the system parameters are probably close to those of the only other neutron-star symbiotic-like binary, GX 1+4. We discuss the similarities and differences between these two systems.Comment: 6 pages, 2 figures; accepted by Ap

    Assessing the economic impacts of food hubs on regional economies: a framework that includes opportunity cost

    Get PDF
    Includes bibliographical references (pages 168-171).The number of food hubs—businesses that aggregate and distribute local food—in the United States is growing, fueled in part by increasing public support. However, there have been few data-driven assessments of the economic impacts of these ventures. Using an input-output-based methodology and a unique data set from a successful food hub, we measure net and gross impacts of a policy supporting their development. We estimate a gross output multiplier of 1.75 and an employment multiplier of 2.14. Using customer surveys, we estimate that every 1increaseinfinaldemandforfoodhubproductsgeneratesa1 increase in final demand for food hub products generates a 0.11 reduction in purchases in other sectors

    Model-based prediction of optogenetic sound encoding in the human cochlea by future optical cochlear implants

    Get PDF
    When hearing fails, electrical cochlear implants (eCIs) partially restore hearing by direct stimulation of spiral ganglion neurons (SGNs). As light can be better confined in space than electrical current, optical CIs (oCIs) provide more spectral information promising a fundamental improvement of hearing restoration by cochlear implants. Here, we turned to computer modelling for predicting the outcome of optogenetic hearing restoration by future oCIs in humans. We combined three-dimensional reconstruction of the human cochlea with ray-tracing simulation of emission from LED or laser-coupled waveguide emitters of the oCI. Irradiance was read out at the somata of SGNs. The irradiance values reached with waveguides were about 14 times higher than with LEDs, at the same radiant flux of the emitter. Moreover, waveguides outperformed LEDs regarding spectral selectivity. oCIs with either emitter type showed greater spectral selectivity when compared to eCI. In addition, modeling the effects of the source-to-SGN distance, orientation of the sources and impact of scar tissue further informs the development of optogenetic hearing restoration

    Did aid promote democracy in Africa?: the role of technical assistance in Africa’s transitions

    Get PDF
    Did foreign aid impede or catalyze democratization in Africa in the 1990s? We argue that after the Cold War, donors increased their use of technical assistance in aid packages, improving their monitoring capacity and thus reducing autocrats’ ability to use aid for patronage. To remain in power, autocrats responded by conceding political rights to their opponents—from legalizing opposition parties to staging elections. We test our theory with panel data for all sub-Saharan African countries. While other factors played pivotal roles in Africa’s political liberalization, we find technical assistance helps to explain the timing and extent of Africa’s democratization

    Scaling of plasma parameters in the SOL and divertor for Alcator C-Mod

    Get PDF

    Facial Cosmetics Have Little Effect on Attractiveness Judgments Compared with Identity

    Get PDF
    The vast majority of women in modern societies use facial cosmetics, which modify facial cues to attractiveness. However, the size of this increase remains unclear - how much more attractive are individuals after an application of cosmetics? Here, we utilised a 'new statistics' approach, calculating the effect size of cosmetics on attractiveness using a within-subjects design, and compared this with the effect size due to identity - that is, the inherent differences in attractiveness between people. Women were photographed with and without cosmetics, and these images were rated for attractiveness by a second group of participants. The proportion of variance in attractiveness explained by identity was much greater than the variance within models due to cosmetics. This result was unchanged after statistically controlling for the perceived amount of cosmetics that each model used. Although cosmetics increase attractiveness, the effect is small, and the benefits of cosmetics may be inflated in everyday thinking. © 2015, Pion Limited. All rights reserved
    • …
    corecore