2,611 research outputs found
Can fear cause economic collapse? Insights from an experimental study
"Wir untersuchen das Verhalten experimenteller Subjekte, die in Anwesenheit
von Netzexternalitäten (externen Effekten) eine Reihe von riskanten Investitionsentscheidungen
machen sollen. Die Subjekte folgen einer einfachen
Heuristik – sie investieren nach positiven Erfahrungen, nach einem Misserfolg
reduzieren sie ihre Investitionsneigung. Diese Resultate stehen im Gegensatz
zu den theoretischen Befunden von Jeitschko und Taylor (2001), in welchen
sogar die Agenten, die ausschlieĂźlich positive Erfahrungen gemacht haben,
schließlich aufhören zu investieren, weil sie Angst haben, dass die anderen, mit
schlechteren Erfahrungen, ausscheiden werden. Theoretisch kann diese 'Bayesianische Angst' einen plötzlichen Wirtschaftszusammenbruch auslösen – auch in dem effizientesten Bayesianischen Gleichgewicht. Im Experiment sind die Subjekte überraschend furchtlos bezüglich der Erfahrungen der anderen. Sie folgen einfach nur eigenen Erfahrungen und verhindern so den totalen
Zusammenbruch." (Autorenreferat)"We study the behavior of experimental subjects who have to make a sequence
of risky investment decisions in the presence of network externalities. Subjects
follow a simple heuristic – investing after positive experiences and reducing
their propensity to invest after a failure. This result contrasts with the theoretical
findings of Jeitschko and Taylor (2001) in which even agents who have only
good experiences eventually stop investing because they are afraid that others
with worse experiences will quit. In theory, this 'Bayesian fear' can trigger
sudden economic collapse – even in the most efficient Bayesian equilibrium. In
the experiment, subjects are surprisingly fearless of others’ experiences, and
simply follow their own experiences, thus averting a total collapse." (author's abstract
Nonlocal feedback in ferromagnetic resonance
Ferromagnetic resonance in thin films is analyzed under the influence of
spatiotemporal feedback effects. The equation of motion for the magnetization
dynamics is nonlocal in both space and time and includes isotropic, anisotropic
and dipolar energy contributions as well as the conserved Gilbert- and the
non-conserved Bloch-damping. We derive an analytical expression for the
peak-to-peak linewidth. It consists of four separate parts originated by
Gilbert damping, Bloch-damping, a mixed Gilbert-Bloch component and a
contribution arising from retardation. In an intermediate frequency regime the
results are comparable with the commonly used Landau-Lifshitz-Gilbert theory
combined with two-magnon processes. Retardation effects together with Gilbert
damping lead to a linewidth the frequency dependence of which becomes strongly
nonlinear. The relevance and the applicability of our approach to ferromagnetic
resonance experiments is discussed.Comment: 22 pages, 9 figure
Fuzzy supervisory control strategies to minimize energy use of airport terminal buildings
Airport terminal buildings are among energy most
consuming buildings and this presents huge opportunities for
implementing energy saving strategies. Achieving satisfactory
control of these buildings using classical controllers alone is
difficult because they contain components that are complex, nonlinear
but dynamically related. Therefore, this paper presents
and appraises fuzzy control strategies for reducing energy
consumptions while simultaneously providing comfort for
passengers in an airport terminal building. The inputs into this
fuzzy supervisory controller are the time schedule for arrival and
departure of passenger planes as well as the expected number of
passengers during each flight, zone illuminance and external
temperature. The controller outputs optimised temperature,
airflow rates and lighting setpoints for the conventional
controllers. Simulation studies in MATLAB/SIMULINK
confirmed the capacity of this control strategy to provide comfort
setpoints for the passengers at reduced energy
Evaluation of indoor environment system performance for airport buildings
Airport terminals are energy intensive buildings. They are mostly thought to operate on a 24/7 scale and so indoor environment systems run on full schedules and do not have fine control based on detailed passenger flow information. While this assumption of round-the-clock operation may be true for the public areas of the airport building and so opportunity for complete shut-down of HVAC and lighting systems are limited especially in a busy airport terminals, there are many passenger exclusive area within the airport in which occupancy varies strictly with flight schedules. This paper presents the results of indoor environment measurement and flight schedules to identify such opportunities and to implement energy conservation measure in the passenger exclusive areas of the airport building. It also uses building simulation to assess the benefits of such energy saving interventions in terms of comfort, energy and carbon emission savings
Has the regulation of non-GAAP disclosures influenced managers' use of aggressive earnings exclusions?
The frequency of non-GAAP (“pro forma”) reporting has continued to increase in the U.S. over the last decade despite preliminary evidence that regulatory intervention led to a decline in non-GAAP disclosures. In particular, the Sarbanes-Oxley Act of 2002 (SOX) and Regulation G (2003) impose strict requirements related to the reporting of non-GAAP numbers. More recently, the SEC has renewed its emphasis on non-GAAP reporting and declared it a “fraud risk factor.” Given the SEC’s renewed emphasis on non-GAAP disclosures, we explore the extent to which regulation has curbed potentially misleading disclosures by investigating two measures of aggressive non-GAAP reporting. Consistent with the intent of Congress and the SEC, we find some evidence that managers report adjusted earnings metrics more cautiously in the post-SOX regulatory environment. Specifically, the results suggest that firms reporting non-GAAP earnings in the post-SOX period are less likely to (1) exclude recurring items incremental to those excluded by analysts and (2) use non-GAAP exclusions to meet strategic earnings targets on a non-GAAP basis that they miss based on I/B/E/S actual earnings. However, we also find that some firms exclude specific recurring items aggressively. Overall, the results suggest that while regulation has generally reduced aggressive non-GAAP reporting, some firms continue to disclose non-GAAP earnings numbers that could be misleading in the post-SOX regulatory environment
Designing an occupancy flow-based controller for airport terminals
One of the most cost-effective ways to save energy in commercial buildings is through designing a dedicated controller for adjusting environmental set-points according occupancy flow. This paper presents the design of a fuzzy rule-based supervisory controller for reducing energy consumptions while simultaneously providing comfort for passengers in a large airport terminal building. The inputs to the controller are the time schedule of the arrival and departure of passenger planes as well as the expected number of passengers, zone global illuminance (daylight) and external temperature. The outputs from the controller are optimised temperature, airflow and lighting set-point profiles for the building. The supervisory controller was designed based on expert knowledge in MATLAB/Simulink, and then validated using simulation studies. The simulation results demonstrate significant potential for energy savings in the controller's ability to maintain comfort by adjusting set-points according to the flow of passengers.
Practical application : The systematic approach adopted here, including the use of artificial intelligence to design supervisory controllers, can be extended to other large buildings which have variable but predictable occupancy patterns like the restricted area of the airport terminal building
Investigating the performance of a combined solar system with heat pump for houses
The UK government has committed to generate 20% of the country's energy from renewable sources by 2020. This paper investigates energy reduction in houses by using an innovative solar thermal collector combined with a heat pump system. The dynamic lumped parameter model for a small house is derived and the combined heating system is used to provide the typical hot water and heating requirement. The goal is to maintain thermal comfort inside the house and reduce the amount of electricity consumption used for heating and hot water. This is achieved by reducing the electricity costs through optimising the operation of the heat pump, integrating the available solar energy, and by shifting electricity consumption to the cheaper night time tariff. Models of conventional controller on–off and a multi-variable model predictive control (MPC) are developed and used for several different climatic conditions. The results showed that the model predictive controller performed best by providing better comfort, consuming less electric energy and better use of cheap night time electricity by load shifting and storing heat energy in the heating tank
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Strongly phosphorescent transition metal π complexes of boron-boron triple bonds
Herein are reported the first π complexes of compounds with boron-boron triple bonds to transition metals, in this case CuI. Three different compounds were isolated that differ in the number of copper atoms bound to the BB unit. Metallation of the B-B triple bonds causes significant lengthening of the B-B and B-CNHC bonds, as well as large upfield shifts of the 11B NMR signals, suggesting greater orbital interactions between the boron and transition metal atoms than those observed with recently published diboryne / alkali metal cation complexes. In contrast to previously-reported fluorescent copper(I) π complexes of boron-boron double bonds, the Cun-π-diboryne compounds (n = 2, 3) show intense phosphorescence in the red to near-IR region from their triplet excited states, according to their microsecond lifetimes, with quantum yields of up to 58%. The bonding situation, as well as the unusual photophysical properties, has been further corroborated by DFT studies
Efficient measurement of quantum gate error by interleaved randomized benchmarking
We describe a scalable experimental protocol for obtaining estimates of the
error rate of individual quantum computational gates. This protocol, in which
random Clifford gates are interleaved between a gate of interest, provides a
bounded estimate of the average error of the gate under test so long as the
average variation of the noise affecting the full set of Clifford gates is
small. This technique takes into account both state preparation and measurement
errors and is scalable in the number of qubits. We apply this protocol to a
superconducting qubit system and find gate errors that compare favorably with
the gate errors extracted via quantum process tomography.Comment: 5 pages, 2 figures, published versio
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