16,520 research outputs found
On the effects of changing mortality patterns on investment, labour and consumption under uncertainty
In this paper we extend the consumption-investment life cycle model for an
uncertain-lived agent, proposed by Richard (1974), to allow for
exible labor supply. We further study the consumption, labor supply and portfolio decisions of an agent facing age-dependent mortality risk, as presented by UK actuarial life tables spanning the time period from 1951-2060 (including mortality forecasts). We find that historical changes in mortality produces significant changes in portfolio investment (more risk taking), labour (decrease of hours) and consumption level (shift to higher level) contributing
up to 5% to GDP growth during the period from 1980 until 2010
New BCJ representations for one-loop amplitudes in gauge theories and gravity
We explain a procedure to manifest the Bern-Carrasco-Johansson duality
between color and kinematics in -point one-loop amplitudes of a variety of
supersymmetric gauge theories. Explicit amplitude representations are
constructed through a systematic reorganization of the integrands in the
Cachazo-He-Yuan formalism. Our construction holds for any nonzero number of
supersymmetries and does not depend on the number of spacetime dimensions. The
cancellations from supersymmetry multiplets in the loop as well as the
resulting power counting of loop momenta is manifested along the lines of the
corresponding superstring computations. The setup is used to derive the
one-loop version of the Kawai-Lewellen-Tye formula for the loop integrands of
gravitational amplitudes.Comment: 58 + 15 page
False Data Injection Attacks on Phasor Measurements That Bypass Low-rank Decomposition
This paper studies the vulnerability of phasor measurement units (PMUs) to
false data injection (FDI) attacks. Prior work demonstrated that unobservable
FDI attacks that can bypass traditional bad data detectors based on measurement
residuals can be identified by detector based on low-rank decomposition (LD).
In this work, a class of more sophisticated FDI attacks that captures the
temporal correlation of PMU data is introduced. Such attacks are designed with
a convex optimization problem and can always bypass the LD detector. The
vulnerability of this attack model is illustrated on both the IEEE 24-bus RTS
and the IEEE 118-bus systems.Comment: 6 pages, 4 figures, submitted to 2017 IEEE International Conference
on Smart Grid Communications (SmartGridComm
Optimal management and inflation protection for defined contribution pension plans
Due to the increasing risk of inflation and diminishing pension benefits, insurance companies have started selling in°ation-linked products. Selling such products the insurance company takes over some or all of the inflation risk from their customers. On the other side financial derivatives which are linked to inflation such as inflation linked bonds are traded on financial markets and appear to be of increasing popularity. The insurance company can use these products to hedge its own inflation risk. In this article we study how to optimally manage a pension fund taking positions in a money market account, a stock and an inflation linked bond, while financing investments through a continuous stochastic income stream such as the plan member's contributions. We use the martingale method in order to compute an analytic expression for the optimal strategy and express it in terms of observable market variables.Pension mathematics; in°ation; long-term investment; stochastic optimal control; martingale method
The Unreasonable Effectiveness of Deep Features as a Perceptual Metric
While it is nearly effortless for humans to quickly assess the perceptual
similarity between two images, the underlying processes are thought to be quite
complex. Despite this, the most widely used perceptual metrics today, such as
PSNR and SSIM, are simple, shallow functions, and fail to account for many
nuances of human perception. Recently, the deep learning community has found
that features of the VGG network trained on ImageNet classification has been
remarkably useful as a training loss for image synthesis. But how perceptual
are these so-called "perceptual losses"? What elements are critical for their
success? To answer these questions, we introduce a new dataset of human
perceptual similarity judgments. We systematically evaluate deep features
across different architectures and tasks and compare them with classic metrics.
We find that deep features outperform all previous metrics by large margins on
our dataset. More surprisingly, this result is not restricted to
ImageNet-trained VGG features, but holds across different deep architectures
and levels of supervision (supervised, self-supervised, or even unsupervised).
Our results suggest that perceptual similarity is an emergent property shared
across deep visual representations.Comment: Accepted to CVPR 2018; Code and data available at
https://www.github.com/richzhang/PerceptualSimilarit
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