6,536 research outputs found
Subjective Expected Utility Theory with “Small Worlds”
We model the notion of a "small world" as a context dependent state space embedded into the "grand world". For each situation the decision maker creates a "small world" reflecting the events perceived to be relevant for the act under consideration. The "grand world" is represented by an event space which is a more general construction than a state space. We retain preference axioms similar in spirit to the Savage axioms and obtain, without abandoning linearity of expectations, a subjective expected utility theory which allows for an intuitive distinction between risk and uncertainty. We also obtain separation of subjective probability and utility as in the state space models.subjective expected utility; decision making under uncertainty; uncertainty aversion; Ellsberg paradox
Effect of asphericity in caustic mass estimates of galaxy clusters
The caustic technique for measuring mass profiles of galaxy clusters relies
on the assumption of spherical symmetry. When applied to aspherical galaxy
clusters, the method yields mass estimates affected by the cluster orientation.
Here we employ mock redshift catalogues generated from cosmological simulations
to study the effect of clusters intrinsic shape and surrounding filamentary
structures on the caustic mass estimates. To this end, we develop a new method
for removing perturbations from large-scale structures, modelled as the
two-halo term, in a caustic analysis of stacked cluster data.
We find that the cluster masses inferred from kinematical data of ~10^14 Msun
clusters observed along the major axis are larger than masses from those
observed along the minor axis by a factor of 1.7 within the virial radius,
increasing to 1.8 within three virial radii. This discrepancy increases by 20%
for the most massive clusters. In addition a smaller but still significant mass
discrepancy arises when filamentary structures are present near a galaxy
cluster.
We find that the mean cluster mass from random sightlines is unbiased at all
radii and their scatter ranges from 0.14 to 0.17 within one and three virial
radii, with a 40% increase for the most massive clusters. We provide tables
which estimate the caustic mass bias given observational constraints on the
cluster orientation.Comment: 19 pages, 9 figures, 6 tables, accepted for publication in MNRA
Assessment of Optimal Flexibility in Ensemble of Frequency Responsive Loads
Potential of electrical loads in providing grid ancillary services is often
limited due to the uncertainties associated with the load behavior. A knowledge
of the expected uncertainties with a load control program would invariably
yield to better informed control policies, opening up the possibility of
extracting the maximal load control potential without affecting grid
operations. In the context of frequency responsive load control, a
probabilistic uncertainty analysis framework is presented to quantify the
expected error between the target and actual load response, under uncertainties
in the load dynamics. A closed-form expression of an optimal demand
flexibility, minimizing the expected error in actual and committed flexibility,
is provided. Analytical results are validated through Monte Carlo simulations
of ensembles of electric water heaters.Comment: IEEE International Conference on Smart Grid Communication
Northern Oil & Gas Strategic Audit
Northern Oil & Gas is an energy company that operates in various basins across the United States. The company utilizes a non-operating model, meaning it does not drill wells or operate rigs, but rather partners with operators and acquires fractional working interests in drilling units. This report seeks to understand Northern Oil & Gas’ business model by examining its competitive strategy, advantages, and resources. Internal and external environmental factors are also analyzed using both PESTEL analysis and Porter’s Five Forces. In addition, key challenges facing the company are explored and recommendations are given on how Northern Oil & Gas can overcome these obstacles and sustain a competitive advantage
Real-Time Local Volt/VAR Control Under External Disturbances with High PV Penetration
Volt/var control (VVC) of smart PV inverter is becoming one of the most
popular solutions to address the voltage challenges associated with high PV
penetration. This work focuses on the local droop VVC recommended by the grid
integration standards IEEE1547, rule21 and addresses their major challenges
i.e. appropriate parameters selection under changing conditions, and the
control being vulnerable to instability (or voltage oscillations) and
significant steady state error (SSE). This is achieved by proposing a two-layer
local real-time adaptive VVC that has two major features i.e. a) it is able to
ensure both low SSE and control stability simultaneously without compromising
either, and b) it dynamically adapts its parameters to ensure good performance
in a wide range of external disturbances such as sudden cloud cover, cloud
intermittency, and substation voltage changes. A theoretical analysis and
convergence proof of the proposed control is also discussed. The proposed
control is implementation friendly as it fits well within the integration
standard framework and depends only on the local bus information. The
performance is compared with the existing droop VVC methods in several
scenarios on a large unbalanced 3-phase feeder with detailed secondary side
modeling.Comment: IEEE Transactions on Smart Grid, 201
Utilizing the Public on Public Lands: The Application of Community Science to Monitor and Model Erosion in National Forests
Unpaved forest roads are adversely affecting coldwater streams through excessive erosion and the subsequent sedimentation of adjacent waterways. To help identify areas of concern, Trout Unlimited (TU) in the Southern Appalachian region developed a Community Science initiative to gather data on sediment sources and stream-road crossings. Volunteers were recruited and trained to monitor road and trail conditions and collect and submit data using a Survey123 application on their cell phones. Analysis of the contributed data reveals statistical connections between drainage type and both erosion level and stream sedimentation. The contributed data were also included as a calibration for the lite version of the Geomorphic Road Analysis and Inventory Package (GRAIP-Lite), a GIS-based road sediment contribution model. The analysis found statistically significant differences between Basic and Calibrated models at one of two sites, and substantial increases in sediment delivery from the Alternate model at both sites
Liberty and Obligation:The Moral Lifeworlds of White Middle-Class Americans in Northeastern and Southern US
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