13,081 research outputs found
Models and techniques for hotel revenue management using a rolling horizon.
This paper studies decision rules for accepting reservations for stays in a hotel based on deterministic and stochastic mathematical programming techniques. Booking control strategies are constructed that include ideas for nesting, booking limits and bid prices. We allow for multiple day stays. Instead of optimizing a decision period consisting of a fixed set of target booking days, we simultaneously optimize the complete range of target booking dates that are open for booking at the moment of optimization. This yields a rolling horizon of overlapping decision periods, which will conveniently capture the effects of overlapping stays.Revenue management;Mathematical programming;Yield management
Models and Techniques for Hotel Revenue Management Using a Roling Horizon
AbstractThis paper studies decision rules for accepting reservations for stays in a hotel based on deterministic and stochastic mathematical programming techniques. Booking control strategies are constructed that include ideas for nesting, booking limits and bid prices. We allow for multiple day stays. Instead of optimizing a decision period consisting of a fixed set of target booking days, we simultaneously optimize the complete range of target booking dates that are open for booking at the moment of optimization. This yields a rolling horizon of overlapping decision periods, which will conveniently capture the effects of overlapping stays.mathematical programming;Revenue Management;yield management
State-recycling and time-resolved imaging in topological photonic lattices
Photonic lattices - arrays of optical waveguides - are powerful platforms for
simulating a range of phenomena, including topological phases. While probing
dynamics is possible in these systems, by reinterpreting the propagation
direction as "time," accessing long timescales constitutes a severe
experimental challenge. Here, we overcome this limitation by placing the
photonic lattice in a cavity, which allows the optical state to evolve through
the lattice multiple times. The accompanying detection method, which exploits a
multi-pixel single-photon detector array, offers quasi-real time-resolved
measurements after each round trip. We apply the state-recycling scheme to
intriguing photonic lattices emulating Dirac fermions and Floquet topological
phases. In this new platform, we also realise a synthetic pulsed electric
field, which can be used to drive transport within photonic lattices. This work
opens a new route towards the detection of long timescale effects in engineered
photonic lattices and the realization of hybrid analogue-digital simulators.Comment: Comments are welcom
Generation and remote detection of THz sound using semiconductor superlattices
The authors introduce a novel approach to study the propagation of high
frequency acoustic phonons in which the generation and detection involves two
spatially separated superlattices apart. Propagating modes
of frequencies up to escape from the superlattice where they
are generated and reach the second superlattice where they are detected. The
measured frequency spectrum reveals finite size effects, which can be accounted
for by a continuum elastic model.Comment: Submitted to Applied Physics Letter
Valence Quark Distribution in A=3 Nuclei
We calculate the quark distribution function for 3He/3H in a relativistic
quark model of nuclear structure which adequately reproduces the nucleon
approximation, nuclear binding energies, and nuclear sizes for small nuclei.
The results show a clear distortion from the quark distribution function for
individual nucleons (EMC effect) arising dominantly from a combination of
recoil and quark tunneling effects. Antisymmetrization (Pauli) effects are
found to be small due to limited spatial overlaps. We compare our predictions
with a published parameterization of the nuclear valence quark distributions
and find significant agreement.Comment: 18pp., revtex4, 4 fig
Influence of leaf trichomes on predatory mite ( Typhlodromus pyri ) abundance in grape varieties
Non-glandular leaf trichomes positively influence the abundance of many phytoseiid mites. We characterized the influence of grape leaf trichomes (domatia, hairs, and bristles) on Typhlodromus pyri Scheuten abundance over two years in a common garden planting of many grape varieties and 2years of sampling in a commercial vineyard. In general, a lack of trichomes was associated with much lower predator numbers and in the case of Dechaunac, a cultivar with almost no trichomes, very few T. pyri were found. Phytoseiid abundance was best predicted by a model where domatia and hair had an additive effect (r 2=0.815). Over two years of sampling at a commercial vineyard there were T. pyri present on all of the 5 cultivars except Dechaunac. At the same time, European red mite prey were present on Dechaunac alone. These results suggest that on grape cultivars lacking leaf trichomes, T. pyri likely will not attain sufficient densities to provide biological control of European red mite, despite presence of the mite food source. The relationship between leaf trichomes and phytoseiid abundance that is observed at the scale of single vines in a garden planting appears to also be manifest at the scale of a commercial vineyard. Because persistence of predatory mites in or nearby the habitats of prey mites is important for effective mite biological control, leaf trichomes, through their influence on phytoseiid persistence, may be critical for successful mite biological control in some system
Metacognition as Evidence for Evidentialism
Metacognition is the monitoring and controlling of cognitive processes. I examine the role of metacognition in âordinary retrieval casesâ, cases in which it is intuitive that via recollection the subject has a justiïŹed belief. Drawing on psychological research on metacognition, I argue that evidentialism has a unique, accurate prediction in each ordinary retrieval case: the subject has evidence for the proposition she justiïŹedly believes. But, I argue, process reliabilism has no unique, accurate predictions in these cases. I conclude that ordinary retrieval cases better support evidentialism than process reliabilism. This conclusion challenges several common assumptions. One is that non-evidentialism alone allows for a naturalized epistemology, i.e., an epistemology that is fully in accordance with scientiïŹc research and methodology. Another is that process reliabilism fares much better than evidentialism in the epistemology of memory
Building a Strong Corporate Ethical Identity: Key Findings from Suppliers
A recent series of reputational crises underscores the importance of building a strong corporate identity and reputation. The building of Corporate Ethical Identity, a process referred to as âethicalization,â is an important strategic imperative in todayâs world and an integral part of a firmâs attempts to build a strong corporate identity across its various stakeholders. In this process we focus on ethicalization on the part of SAB Ltd, a large South African brewer that is part of the global SABMiller plc, and the impact of its efforts on supplier perceptions. Our findings show that leaders and managers must consider six factors that drive the formation of ethical identity namely, the forming of trusted relationships with stakeholders, having sustainable organizational citizenship, making sure those ethical policies are developed and enforced and the ethical management of procurement contracting, administration and information. We use these findings to infer a model for senior managers to build ethical identity across an organizationâs stakeholders
A Reactive Molecular Dynamics Model for Uranium/Hydrogen Containing Systems
Uranium-based materials are valuable assets in the energy, medical, and
military industries. However, understanding their sensitivity to hydrogen
embrittlement is particularly challenging due to the toxicity of uranium and
computationally expensive nature of the quantum-based methods generally
required to study such processes. In this regard, we have developed a Chebyshev
Interaction Model for Efficient Simulation (ChIMES) model that can be employed
to compute energies and forces of U and UH3 bulk structures with vacancies and
hydrogen interstitials with similar accuracy to Density Functional Theory (DFT)
while yielding linear scaling and orders of magnitude improvement in
computational efficiency. We show that that the bulk structural parameters,
uranium and hydrogen vacancy formation energies, and diffusion barriers
predicted by the ChIMES potential are in strong agreement with the reference
DFT data. We then use ChIMES to conduct molecular dynamics simulations of the
temperature-dependent diffusion of a hydrogen interstitial and determine the
corresponding diffusion activation energy. Our model has particular
significance in studies of actinides and other high-Z materials, where there is
a strong need for computationally efficient methods to bridge length and time
scales between experiments and quantum theory.Comment: Reactive molecular dynamics model for U/H systems based on the ChIMES
reactive force fiel
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