1,587 research outputs found
Comparing Factor Models in European Stock Market
How to construct portfolios is a vital issue for investors and the effective use of asset pricing models can better achieve the goal of risk diversification. Given the large amount of asset pricing models, this paper intended to select a benchmark model that performs the best among a set of prominent asset pricing models in European stock markets. The candidate models included CAPM, the three-factor (FF3), five-factor, and six-factor (FF6) models of Fama and French (1993, 2015, 2018), the four-factor model of Carhart (1997), and a variant of FF6 that contains a more-timely value factor. This paper compared their abilities to explain size-B/M and size-momentum portfolios based on average absolute alphas and average absolute t-statistics. The empirical results showed that FF6 and its variant in general outperforms the other competing models
Faster Random Walks By Rewiring Online Social Networks On-The-Fly
Many online social networks feature restrictive web interfaces which only
allow the query of a user's local neighborhood through the interface. To enable
analytics over such an online social network through its restrictive web
interface, many recent efforts reuse the existing Markov Chain Monte Carlo
methods such as random walks to sample the social network and support analytics
based on the samples. The problem with such an approach, however, is the large
amount of queries often required (i.e., a long "mixing time") for a random walk
to reach a desired (stationary) sampling distribution.
In this paper, we consider a novel problem of enabling a faster random walk
over online social networks by "rewiring" the social network on-the-fly.
Specifically, we develop Modified TOpology (MTO)-Sampler which, by using only
information exposed by the restrictive web interface, constructs a "virtual"
overlay topology of the social network while performing a random walk, and
ensures that the random walk follows the modified overlay topology rather than
the original one. We show that MTO-Sampler not only provably enhances the
efficiency of sampling, but also achieves significant savings on query cost
over real-world online social networks such as Google Plus, Epinion etc.Comment: 15 pages, 14 figure, technical report for ICDE2013 paper. Appendix
has all the theorems' proofs; ICDE'201
Inkjet-printed conductive patterns for physical manipulation of audio signals
In this demo paper, we present the realization of a completely aesthetically driven conductive image as a multi-modal music controller. Combining two emerging technologies - rapid prototyping with an off-the-shelf inkjet printer using conductive ink and parametric graphic design, we are able to create an interactive surface that is thin, flat, and flexible. This sensate surface can be conformally wrapped around a simple curved surface, and unlike touch screens, can accommodate complex structures and shapes such as holes on a surface. We present the design and manufacturing flow and discuss the technology behind this multi-modal sensing design. Our work seeks to offer a new dimension of designing sonic interaction with graphic tools, playing and learning music from a visual perspective and performing with expressive physical manipulation
Low-cost sensor tape for environmental sensing based on roll-to-roll manufacturing process
We describe the concept of fabricating low-cost sensor tape for fine-grid environmental sensing based on roll-to-roll manufacturing processes. We experiment with constructing sensors and electronic connections with low-cost conductive inkjet printed copper traces. Our first attempt is to fabricate humidity sensors by spin-coating conductive polymer on sensor substrates and integrating the design with an embedded system. The humidity sensor was tested in a two-point probe and exhibits the I-V profile of a diode. We demonstrated a working humidity sensor with an impedance variance of 30 kΩ from 99% to 58% RH within 300 seconds under a 1.4 volt bias.Massachusetts Institute of Technology. Media Laborator
Experiences and challenges in deploying potentially invasive sensor systems for dynamic media applications
This paper describes a series of projects that explore a set of dynamic media applications built upon a potentially invasive sensor system - the Ubiquitous Media Portal, featuring high-resolution video and audio capture with user ID/tracking capabilities that we installed throughout our facility. In addition to sensors, the portals provide a display and loudspeaker to locally display information or manifest phenomena from virtual worlds. During an eight-month long period, we implemented four different applications to explore acceptance by our buildingwide users. Our results provide insight into how different levels of information presentation and perceived user control can influence the user acceptance and engagement with such sensor platforms in ubiquitous deployments.Things That Think ConsortiumNokia Research Cente
The consistency test on the cosmic evolution
We propose a new and robust method to test the consistency of the cosmic
evolution given by a cosmological model. It is realized by comparing the
combined quantity r_d^CMB/D_V^SN, which is derived from the comoving sound
horizon r_d from cosmic microwave background (CMB) measurements and the
effective distance D_V derived from low-redshift Type-Ia supernovae (SNe Ia)
data, with direct and independent r_d/D_V obtained by baryon acoustic
oscillation (BAO) measurements at median redshifts. We apply this test method
for the Lambda-CDM and wCDM models, and investigate the consistency of the
derived value of r_d/D_V from Planck 2015 and the SN Ia data sets of Union2.1
and JLA (z<1.5), and the r_d/D_V directly given by BAO data from
six-degree-field galaxy survey (6dFGS), Sloan Digital Sky Survey Data Release 7
Main Galaxy Survey (SDSS-DR7 MGS), DR11 of SDSS-III, WiggleZ and Ly-alpha
forecast surveys from Baryon Oscillation Spectroscopic Data (BOSS) DR-11 over
0.1<z<2.36. We find that r_d^CMB/D_V^SN for both non-flat Lambda-CDM and flat
wCDM models with Union2.1 and JLA data are well consistent with the BAO and CMB
measurements within 1-sigma CL. Future surveys will further tight up the
constraints significantly, and provide stronger test on the consistency.Comment: 11 pages, 5 figures, 4 tables. Version accepted by PR
A cuttable multi-touch sensor
We propose cutting as a novel paradigm for ad-hoc customization of printed electronic components. As a first instantiation, we contribute a printed capacitive multi-touch sensor, which can be cut by the end-user to modify its size and shape. This very direct manipulation allows the end-user to easily make real-world objects and surfaces touch-interactive, to augment physical prototypes and to enhance paper craft. We contribute a set of technical principles for the design of printable circuitry that makes the sensor more robust against cuts, damages and removed areas. This includes novel physical topologies and printed forward error correction. A technical evaluation compares different topologies and shows that the sensor remains functional when cut to a different shape.Deutsche Forschungsgemeinschaft (Cluster of Excellence Multimodal Computing and Interaction, German Federal Excellence Initiative
Signal estimation in cognitive satellite networks for satellite-based industrial internet of things
Satellite industrial Internet of Things (IIoT) plays an important role in industrial manufactures without requiring the support of terrestrial infrastructures. However, due to the scarcity of spectrum resources, existing satellite frequency bands cannot satisfy the demand of IIoT, which have to explore other available spectrum resources. Cognitive satellite networks are promising technologies and have the potential to alleviate the shortage of spectrum resources and enhance spectrum efficiency by sharing both spectral and spatial degrees of freedom. For effective signal estimations, multiple features of wireless signals are needed at receivers, the transmissions of which may cause considerable overhead. To mitigate the overhead, part of parameters, such as modulation order, constellation type, and signal to noise ratio (SNR), could be obtained at receivers through signal estimation rather than transmissions from transmitters to receivers. In this article, a grid method is utilized to process the constellation map to obtain its equivalent probability density function. Then, binary feature matrix of the probability density function is employed to construct a cost function to estimate the modulation order and constellation type for multiple quadrature amplitude modulation (MQAM) signal. Finally, an improved M 2 M ∞ method is adopted to realize the SNR estimation of MQAM. Simulation results show that the proposed method is able to accurately estimate the modulation order, constellation type, and SNR of MQAM signal, and these features are extremely useful in satellite-based IIoT
- …