17,168 research outputs found
Steady-states and kinetics of ordering in bus-route models: connection with the Nagel-Schreckenberg model
A Bus Route Model (BRM) can be defined on a one-dimensional lattice, where
buses are represented by "particles" that are driven forward from one site to
the next with each site representing a bus stop. We replace the random
sequential updating rules in an earlier BRM by parallel updating rules. In
order to elucidate the connection between the BRM with parallel updating
(BRMPU) and the Nagel-Schreckenberg (NaSch) model, we propose two alternative
extensions of the NaSch model with space-/time-dependent hopping rates.
Approximating the BRMPU as a generalization of the NaSch model, we calculate
analytically the steady-state distribution of the {\it time headways} (TH)
which are defined as the time intervals between the departures (or arrivals) of
two successive particles (i.e., buses) recorded by a detector placed at a fixed
site (i.e., bus stop) on the model route. We compare these TH distributions
with the corresponding results of our computer simulations of the BRMPU, as
well as with the data from the simulation of the two extended NaSch models. We
also investigate interesting kinetic properties exhibited by the BRMPU during
its time evolution from random initial states towards its steady-states.Comment: Accepted for publication in EPJ
A payload to evaluate photodiodes for the detection of soft and hard x rays in a space environment using a Get Away Special
We propose to use the Get Away Special (GAS) facility to evaluate P-intrinsic-N (PIN) detectors and avalanche photodiodes (APD's) for the detection of both solar and nonsolar soft and hard x rays. We would like to fly both types of silicon detectors for the direct detection of the x ray photons in the energy range from 1 to 30 keV with an energy resolution of about 1 keV. We would also like to use both types of photodiodes viewing CsI(Tl) scintillators to extend the energy range up to 1 MeV with -6 percent resolution at 660 keV. Solar flares would be detected with this instrumentation during periods of solar pointing providing high energy resolution spectra with high time resolution. Similar data would be obtained in the scanning mode on nonsolar transient and steady x ray sources with the same instrumentation. A commandable door over the detectors would be required to allow measurements to be made as low as 1 keV
The Comovement of Returns and Investment Within the Multinational Firm
Can financial integration, particularly the cross-border investments of multinational firms, help explain the synchronization of business cycles? This paper presents evidence on the comovement of returns and investment within U.S. multinational firms to address this question. These firms constitute significant fractions of economic output and investment in most large economies, suggesting that they could create significant economic linkages. Aggregate measures of rates of return and investment rates of U.S. multinational firms located in different countries are highly correlated across countries. Firm-level regressions demonstrate that rates of return and investment rates of affiliates are highly correlated with the rates of return and investment of the affiliate's parent and other affiliates within the same parent system, controlling for country and industry factors. The evidence on these interrelationships and the importance of multinationals to local economies suggests that global firms may be an important channel for transmitting economic shocks. This evidence also sheds light on asset pricing puzzles related to the diversification benefits provided by multinational firms.
Research and development of open-cycle fuel cells Fourth quarterly progress report, period ending Aug. 15, 1965
Digital computer program for minimizing weight of fuel cell power systems - prelaunch startup and instrumentation - mathematical model of static moisture removal process - fuel cell mode
A MEMS electrostatic particle transportation system
We demonstrate here an electrostatic MEMS system
capable of transporting particles 5-10ÎĽm in diameter in
air. This system consists of 3-phase electrode arrays
covered by insulators (Figs. 1, 2). Extensive testing of
this system has been done using a variety of insulation
materials (silicon nitride, photoresist, and Teflon),
thickness (0- 12ÎĽm), particle sizes (1-10ÎĽm), particle
materials (metal, glass, polystyrene, spores, etc),
waveforms, frequencies, and voltages. Although
previous literature [1-2] claimed it impractical to
electrostatically transport particles with sizes 5-10ÎĽm
due to complex surface forces, this effort actually
shows it feasible (as high as 90% efficiency) with the
optimal combination of insulation thickness, electrode
geometry, and insulation material. Moreover, we suggest a qualitative theory for our particle transportation system which is consistent with our data and finite-element electrostatic simulations
Multinational Firms, FDI Flows and Imperfect Capital Markets
This paper examines how costly financial contracting and weak investor protection influence the cross-border operational, financing and investment decisions of firms. We develop a model in which product developers have a comparative advantage in monitoring the deployment of their technology abroad. The paper demonstrates that when firms want to exploit technologies abroad, multinational firm (MNC) activity and foreign direct investment (FDI) flows arise endogenously when monitoring is nonverifiable and financial frictions exist. The mechanism generating MNC activity is not the risk of technological expropriation by local partners but the demands of external funders who require MNC participation to ensure value maximization by local entrepreneurs. The model demonstrates that weak investor protections limit the scale of multinational firm activity, increase the reliance on FDI flows and alter the decision to deploy technology through FDI as opposed to arm's length licensing. Several distinctive predictions for the impact of weak investor protection on MNC activity and FDI flows are tested and confirmed using firm-level data.
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