9,539 research outputs found
The Relative Merits of Investable Hedge Fund Indices and of Funds of Hedge Funds in Optimal Passive Portfolios
Can the new investable hedge fund indices (IHF) enhance the performance of optimal passive portfolios made of equities and bonds? How do they compare to funds of hedge funds (FoHF) as well as to other alternative investments such as commodities and volatility? The conclusions depend crucially on forecasts of future expected excess returns for all assets as well as a careful conditioning of the data to reflect trading costs and remove unrealistic serial correlations. A naĂŻve forecast based on recent historical performance leads to no allocations to either IHF or FoHF, a result explained by the performance of equities and commodities and limited diversification effects from hedge funds. Yet a forecast based on market equilibrium returns for all main asset classes but hedge funds, which are kept at their historical level, leads to the opposite result with optimal portfolios almost exclusively invested in hedge funds. Both conclusions are unrealistic and unstable. More reasonable allocations are obtained with the Black-Litterman (BL) approach to combining subjective views with equilibrium returns. Then both hedge funds instruments play a significant role in optimal passive portfolios if their expected excess returns are at least 1%. Long volatility positions are also likely to be attractive. However the BL approach can also be criticised.hedge funds, investable hedge funds indices, funds of hedge funds, commodities, VIX, mean-variance analysis, Sharpe Ratio, Adjusted Sharpe Ratio, Omega Ratio, Black Litterman model
CoFeD: A visualisation framework for comparative quality evaluation
Evaluation for the purpose of selection can be a challenging task particularly when there is a plethora of choices available. Short-listing, comparisons and eventual choice(s) can be aided by visualisation techniques. In this paper we use Feature Analysis, Tabular and Tree Representations and Composite Features Diagrams (CFDs) for profiling user requirements and for top-down profiling and evaluation of items (methods, tools, techniques, processes and so on) under evaluation. The resulting framework CoFeD enables efficient visual comparison and initial short-listing. The second phase uses bottom-up quantitative evaluation which aids the elimination of the weakest items and hence the effective selection of the most appropriate item.
The versatility of the framework is illustrated by a case study comparison and evaluation of two agile methodologies. The paper concludes with limitations and indications of further work
Art Beyond the Globe: Lucio Fontana’s Spatial Identity
In several works produced in the 1950s and 60s, the Argentine-Italian artist Lucio Fontana (1899 – 1968) proposed that the advent of space travel would lead to a profound decentring of human identity. In this article selected works by Fontana are discussed with reference to statements made by the artist and his contemporary critics as well as to more recent, theoretical writings on space and the body. It is argued that Fontana put forward in his work the idea that travel through outer space would render the image of the modern subject unrecognisable
Gravitational waves and electroweak baryogenesis in a global study of the extended scalar singlet model
We perform a global fit of the extended scalar singlet model with a fermionic
dark matter (DM) candidate. Using the most up-to-date results from the
measured DM relic density, direct detection limits from the
XENON1T (2018) experiment, electroweak precision observables and Higgs searches
at colliders, we constrain the 7-dimensional model parameter space. We also
find regions in the model parameter space where a successful electroweak
baryogenesis (EWBG) can be viable. This allows us to compute the gravitational
wave (GW) signals arising from the phase transition, and discuss the potential
discovery prospects of the model at current and future GW experiments. Our
global fit places a strong upper lower limit on the second
scalar mass, the fermion DM mass and the scalar-fermion DM coupling. In
agreement with previous studies, we find that our model can simultaneously
yield a strong first-order phase transition and saturate the observed DM
abundance. More importantly, the GW spectra of viable points can often be
within reach of future GW experiments such as LISA, DECIGO and BBO.Comment: 42 pages, 10 figures and 2 tables; v2: updated references, submitted
to JHEP; v3: corrected typos and updated references, matches version
published in JHE
LUX likelihood and limits on spin-independent and spin-dependent WIMP couplings with LUXCalc
We present LUXCalc, a new utility for calculating likelihoods and deriving
WIMP-nucleon coupling limits from the recent results of the LUX direct search
dark matter experiment. After a brief review of WIMP-nucleon scattering, we
derive LUX limits on the spin-dependent WIMP-nucleon couplings over a broad
range of WIMP masses, under standard assumptions on the relevant astrophysical
parameters. We find that, under these and other common assumptions, LUX
excludes the entire spin-dependent parameter space consistent with a dark
matter interpretation of DAMA's anomalous signal, the first time a single
experiment has been able to do so. We also revisit the case of spin-independent
couplings, and demonstrate good agreement between our results and the published
LUX results. Finally, we derive constraints on the parameters of an effective
dark matter theory in which a spin-1 mediator interacts with a fermionic WIMP
and Standard Model fermions via axial-vector couplings. A detailed appendix
describes the use of LUXCalc with standard codes to place constraints on
generic dark matter theories.Comment: 16 pages, 6 figures. Software package included as ancillary files.
v2: added references, Baksan limits. v3: clarifications and small
corrections, results unchange
Including design in e-manufacturing
This paper reviews major issues in the implementation of e-manufacturing, particularly the design aspects. It will examine recent progress, drawing out particular issues that are being addressed. Use will be made of the work by the author and colleagues to devise rule-based design and Internet-based control of machines to illustrate how these developments affect the integrated e-manufacturing environment. A dynamic Simulink model of the way e-manufacture is affected by overall design delays is used to evaluate general solutions for partial and complete e-based companies. These models show how changing to improved designs reduces WI
Cross-correlation of cosmic far-infrared background anisotropies with large scale structures
We measure the cross-power spectra between luminous red galaxies (LRGs) from
the Sloan Digital Sky Survey (SDSS)-III Data Release Eight (DR8) and cosmic
infrared background (CIB) anisotropies from Planck and data from the Improved
Reprocessing (IRIS) of the Infrared Astronomical Satellite (IRAS) at 353, 545,
857, and 3000 GHz, corresponding to 850, 550, 350 and 100 micron, respectively,
in the multipole range 100<l<1000. Using approximately 6.5 10^5 photometrically
determined LRGs in 7760 deg^2 of the northern hemisphere in the redshift range
0.45 < z < 0.65, we model the far-infrared background (FIRB) anisotropies with
an extended version of the halo model. With these methods, we confirm the basic
picture obtained from recent analyses of FIRB anisotropies with Herschel and
Planck, that the most efficient halo mass at hosting star forming galaxies is
log(M_ eff/M_\odot)=12.84+/-0.15. We estimate the percentage of FIRB
anisotropies correlated with LRGs as approximately 11.8 %, 3.9 %, 1.8 %, and
1.0 % of the total at 3000, 857, 545, and 353 GHz, respectively. At redshift
z~0.55, the bias of FIRB galaxies with respect to the dark matter density field
has the value b_{FIRB}~1.45, and the mean dust temperature of FIRB galaxies is
T_d=26 K. Finally, we discuss the impact of present and upcoming
cross-correlations with far-infrared background anisotropies on the
determination of the global star formation history and the link between
galaxies and dark matter.Comment: 9 pages, 6 figures, accepted for publication in A&
Causal judgements about temporal sequences of events in single individuals
Stimuli were presented in which values of an outcome variable for a single individual were recorded over
24 time periods, and an intervention was introduced at one of the time periods. Participants judged
whether and how much the intervention affected the outcome. Judgements were affected by manipulations
of the temporal relation between the intervention and a gradual increase in values on the outcome
variable, by the size of the increase, by the time taken for the increase to occur, and by variance in the
preincrease data. Most results were predicted by a simple model in which the mean outcome value for
the preintervention time periods is subtracted from the mean outcome value for the postintervention
time periods, though there was also an effect of temporal contiguity that is not predicted by the
simple model. This form of information, which is a kind of quasiexperimental design, is more representative
of the kind of information generally available for causal judgement than the more commonly
investigated binary variables in which the cause is either present or absent, and the outcome either
occurs or does not; as such, it is more revealing of how causal judgements are made under the conditions
that prevail in the world
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