pwc-archive/papers-with-abstracts huggingface dataset:
Performance analysis of hybrid FSO/RF communication systems with Alamouti Coding or Antenna Selection
Date: 2018-11-20 00:00:00

In this work a novel dual-hop relay-assisted hybrid Free Space Optical /
Radio Frequency (FSO / RF) communication system is presented. In this system,
RF signal is transmitted from two antennas, and then forwarded by a single
antenna relay through FSO channel. This is the first time that performance of
using Alamouti Coding (AC) or Antenna Selection (AS) at the transmitter of a
hybrid FSO / RF system is investigated. FSO link has Gamma-Gamma atmospheric
turbulence, and in order to get closer to the actual results, the effect of
pointing error is also considered. For the first time closed-form expressions
are derived for Bit Error Rate (BER) and Outage Probability of the proposed
system and validated through MATLAB simulations. Results indicate that in this
structure, there is slight performance difference between AC and AS schemes.
Hence due to more complexity, power consumption and latency of AC, AS is
recommended. Dual-hop, hybrid FSO / RF system significantly improves
performance and reliability of the system, and is particularly suitable for
long-range applications that direct RF communication between source and
destination is not possible. Considering these advantages this structure is
particularly suitable for mobile communications which has power and processing
limitations.
TreeGrafter: phylogenetic tree-based annotation of proteins with Gene Ontology terms and other annotations
Date: 2018-02-20 00:00:00

Summary: TreeGrafter is a new software tool for annotating protein sequences
using annotated phylogenetic trees. Cur-rently, the tool provides annotations
to Gene Ontology terms, and PANTHER protein class, family and subfamily. The
ap-proach is generalizable to any annotations that have been made to internal
nodes of a reference phylogenetic tree. Tree-Grafter takes each input query
protein sequence, finds the best matching homologous family in a library of
pre-calculated, pre-annotated gene trees, and then grafts it to the best
location in the tree. It then annotates the sequence by propagating
anno-tations from its ancestral nodes in the reference tree. We show that
TreeGrafter outperforms subfamily HMM scoring for cor-rectly assigning
subfamily membership, and that it produces highly specific annotations of GO
terms based on annotated reference phylogenetic trees. This method will be
further inte-grated into InterProScan, enabling an even broader user
com-munity.
  Availability: TreeGrafter is freely available on the web at
https://github.com/haimingt/TreeGrafting.
A Novel Hybrid Islanding Detection Method for Inverter-based DG
Date: 2018-02-20 00:00:00

A novel method for achieving a better performance using the combination of
the available passive and active methods has been proposed. The algorithm
detects the islanding in proper time by using harmonic detection, the average
rate of change of voltage and shifting power generation. Harmonic detection in
this method decreases process time and also differentiates between islanding
and other power systems events. For harmonic detection, extended Kalman filter
has been used. Besides, the reliability of the method increases using the
average rate of change of the voltage. The proposed method uses a strategy for
decreasing the non-detection zone. In this strategy, minimum and maximum
average rates of change of voltage limits are defined to improve the security
of the system. Therefore, three main specifications of a proper method,
reliability, security and time of process are achievable by the combination of
these passive and active methods. By applying different power system events
under different power conditions, the proposed method has been verified in
Simulink software.
Performance Comparison of two novel Relay-Assisted Hybrid FSO / RF Communication Systems
Date: 2018-11-20 00:00:00

In this manuscript, two novel multi-hop relay-assisted hybrid Free Space
Optical / Radio Frequency (FSO / RF) communication systems are presented and
compared. In these structures, RF and FSO links, at each hop, are parallel and
send data simultaneously. This is the first time that in a multihop hybrid FSO
/ RF structure, Detect and Forward protocol is used. In the first structure, at
each hop, received signals with higher Signal to Noise Ratio (SNR) is selected.
But in the second structure, at each hop, received FSO and RF signals are
separately detected and forwarded and selection is done only at the last hop.
Considering FSO link in Negative Exponential atmospheric turbulence and RF link
in Rayleigh fading, for the first time, closed-form expressions are derived for
Outage Probability (P_out) and Bit Error Rate (BER) of the proposed structures.
MATLAB simulations are provided to verify derived expressions. The main
motivation of this work is to answer this question that how much is the
difference of selection at each hop and selection at the last hop. Results
indicate that the structure with selection at each hop has better performance
than the structure with selection at the last hop. At different target Outage
Probability, selection at the last hop consumes about two times (~3dB) more
power than selection at each hop. Both structures are particularly suitable for
long-range communications. However, selection at each hop, in the cost of more
complexity, is recommended for applications which have problem with supplying
the required power for communication.
A novel hybrid FSO / RF communication system with receive diversity
Date: 2018-11-20 00:00:00
Tasks: Diversity

In mobile communication system, due to the limitations of mobile device such
as low power supply as well as small size, most of the processing should be
done at the Base Station. Using multi-receive structure at the Base Station
really helps better recovery of the original signal by combining different
received signals. In this paper, for the first time, receive diversity is used
in single-hop hybrid Free Space Optical / Radio Frequency (FSO / RF)
communication system. Also it is the first time that a single-hop hybrid FSO /
RF system is investigated at saturate atmospheric turbulence regime. For the
first time, closed-form expression is derived for Outage Probability of the
proposed system and verified through MATLAB simulation. Results indicate a
significant improvement in the performance of the proposed structure compared
with common FSO and RF systems with receive diversity. Therefore it can be
concluded that although the proposed structure requires a complex receiver, but
addition of this complexity could significantly reduce processing or power
consumption required for performance maintenance of the system.
Extracting the multi-timescale activity patterns of online financial markets
Date: 2018-04-24 00:00:00

Online financial markets can be represented as complex systems where trading
dynamics can be captured and characterized at different resolutions and time
scales. In this work, we develop a methodology based on non-negative tensor
factorization (NTF) aimed at extracting and revealing the multi-timescale
trading dynamics governing online financial systems. We demonstrate the
advantage of our strategy first using synthetic data, and then on real-world
data capturing all interbank transactions (over a million) occurred in an
Italian online financial market (e-MID) between 2001 and 2015. Our results
demonstrate how NTF can uncover hidden activity patterns that characterize
groups of banks exhibiting different trading strategies (normal vs. early vs.
flash trading, etc.). We further illustrate how our methodology can reveal
"crisis modalities" in trading triggered by endogenous and exogenous system
shocks: as an example, we reveal and characterize trading anomalies in the
midst of the 2008 financial crisis.
Differential Bandpass Filters Based on Dumbbell-Shaped Defected Ground Resonators
Date: 2018-02-21 00:00:00

This letter presents a dumbbell-shaped defected ground resonator and its
application in the design of differential filters. The operation principle of
the dumbbell-shaped resonator (DSR) coupled to differential microstrip lines is
studied through a circuit model analysis. The proposed circuit model is
validated through the comparison with the electromagnetic simulation results.
It is shown that the bandpass configuration of microstripline- coupled DSR can
be used to design higher order bandpass filters. The design procedure is
explained by developing a thirdorder filter prototype. The designed filter
shows more than 57 dB common mode rejection within the differential passband.
Stationary distribution of a 2-island 2-allele Wright-Fisher diffusion model with slow mutation and migration rates
Date: 2018-09-26 00:00:00

The stationary distribution of the diffusion limit of the 2-island, 2-allele
Wright-Fisher with small but otherwise arbitrary mutation and migration rates
is investigated. Following a method developed by Burden and Tang (2016, 2017)
for approximating the forward Kolmogorov equation, the stationary distribution
is obtained to leading order as a set of line densities on the edges of the
sample space, corresponding to states for which one island is bi-allelic and
the other island is non-segregating, and a set of point masses at the corners
of the sample space, corresponding to states for which both islands are
simultaneously non-segregating. Analytic results for the corner probabilities
and line densities are verified independently using the backward generator and
for the corner probabilities using the coalescent.
Blockchain: Data Malls, Coin Economies and Keyless Payments
Date: 2018-04-18 00:00:00

We discuss several uses of blockchain (and, more generally, distributed
ledger) technologies outside of cryptocurrencies with a pragmatic view. We
mostly focus on three areas: the role of coin economies for what we refer to as
data malls (specialized data marketplaces); data provenance (a historical
record of data and its origins); and what we term keyless payments (made
without having to know other users' cryptographic keys). We also discuss voting
and other areas, and give a sizable list of academic and nonacademic
references.
Umbilical Cord Blood Banking and its Therapeutic Uses
Date: 2018-02-21 00:00:00

Umbilical cord blood (UBC) can be viewed as the most promising source of stem
cells, in which collection cost is minimal and its benefits are immense. The
cord blood is used to treat malignant and nonmalignant diseases; this is due to
its progenitor characteristics know as stem cells.Its properties of being,
immunologically immature and high plasticity has made it superior to other
sources of stem cells. The stem cells collected from cord blood have neutral
differentiation capabilities which allow medical professionals to produce
functional neural cells from these stem cells.Cord Blood Banking (CBB) is the
storing of the umbilical cord blood which is collected immediately after the
delivery of the baby. Great care and concern are needed for proper storage of
these progenitor cells, hence cord blood banks come into the play, they are of
3 types which are: public, private and direct donation banks.Clinical trials
are still at its very early stages having abundances to still be uncovered but
results were obtained have demonstrated high potential and more scope towards
effective development therapies and treatments for rare disorders.
Narrowband Bandpass Frequency Selective Surface with Miniaturized Elements
Date: 2018-02-21 00:00:00

This article presents a bandpass frequency selective surface (FSS) with a
narrowband frequency response. The designed FSS is made of miniaturized
elements unit cell. The operation principle of the FSS is explained by using an
equivalent circuit model, where the passband bandwidth can be controlled by the
values of the circuit elements corresponding to the geometrical dimensions of
the unit cell. The compatibility of the presented structure in designing higher
order narrowband filtering responses is verified by designing a second-order
bandpass FSS with 8:5% fractional bandwidth with a center frequency of 2:7 GHz.
The Security of the United Kingdom Electricity Imports under Conditions of High European Demand
Date: 2018-02-21 00:00:00

Energy policy in Europe has been driven by the three goals of security of
supply, economic competitiveness and environmental sustainability, referred to
as the energy trilemma. Although there are clear conflicts within the trilemma,
member countries have acted to facilitate a fully integrated European
electricity market. Interconnection and cross-border electricity trade has been
a fundamental part of such market liberalisation. However, it has been
suggested that consumers are exposed to a higher price volatility as a
consequence of interconnection. Furthermore, during times of energy shortages
and high demand, issues of national sovereignty take precedence over
cooperation. In this article, the unique and somewhat peculiar conditions of
early 2017 within France, Germany and the United Kingdom have been studied to
understand how the existing integration arrangements address the energy
trilemma. It is concluded that the dominant interests are economic and national
security; issues of environmental sustainability are neglected or overridden.
Although the optimisation of European electricity generation to achieve a lower
overall carbon emission is possible, such a goal is far from being realised.
Furthermore, it is apparent that the United Kingdom, and other countries,
cannot rely upon imports from other countries during periods of high demand
and/or limited supply.
Early warning signals in plant disease outbreaks
Date: 2018-12-14 00:00:00

Summary
  1. Infectious disease outbreaks in plants threaten ecosystems, agricultural
crops and food trade. Currently, several fungal diseases are affecting forests
worldwide, posing a major risk to tree species, habitats and consequently
ecosystem decay. Prediction and control of disease spread are difficult, mainly
due to the complexity of the interaction between individual components
involved.
  2. In this work, we introduce a lattice-based epidemic model coupled with a
stochastic process that mimics, in a very simplified way, the interaction
between the hosts and pathogen. We studied the disease spread by measuring the
propagation velocity of the pathogen on the susceptible hosts. Quantitative
results indicate the occurrence of a critical transition between two stable
phases: local confinement and an extended epiphytotic outbreak that depends on
the density of the susceptible individuals.
  3. Quantitative predictions of epiphytotics are performed using the framework
early-warning indicators for impending regime shifts, widely applied on
dynamical systems. These signals forecast successfully the outcome of the
critical shift between the two stable phases before the system enters the
epiphytotic regime.
  4. Synthesis: Our study demonstrates that early-warning indicators could be
useful for the prediction of forest disease epidemics through mathematical and
computational models suited to more specific pathogen-host-environmental
interactions.
CABS-flex 2.0: a web server for fast simulations of flexibility of protein structures
Date: 2018-02-21 00:00:00

Classical simulations of protein flexibility remain computationally
expensive, especially for large proteins. A few years ago, we developed a fast
method for predicting protein structure fluctuations that uses a single protein
model as the input. The method has been made available as the CABS-flex web
server and applied in numerous studies of protein structure-function
relationships. Here, we present a major update of the CABS-flex web server to
version 2.0. The new features include: extension of the method to significantly
larger and multimeric proteins, customizable distance restraints and simulation
parameters, contact maps and a new, enhanced web server interface. CABS-flex
2.0 is freely available at http://biocomp.chem.uw.edu.pl/CABSflex2
Improving Recommender Systems Beyond the Algorithm
Authors: Schnabel Tobias, Bennett Paul N., Joachims Thorsten
Date: 2018-02-21 00:00:00
Tasks: Recommendation Systems

Recommender systems rely heavily on the predictive accuracy of the learning
algorithm. Most work on improving accuracy has focused on the learning
algorithm itself. We argue that this algorithmic focus is myopic. In
particular, since learning algorithms generally improve with more and better
data, we propose shaping the feedback generation process as an alternate and
complementary route to improving accuracy. To this effect, we explore how
changes to the user interface can impact the quality and quantity of feedback
data -- and therefore the learning accuracy. Motivated by information foraging
theory, we study how feedback quality and quantity are influenced by interface
design choices along two axes: information scent and information access cost.
We present a user study of these interface factors for the common task of
picking a movie to watch, showing that these factors can effectively shape and
improve the implicit feedback data that is generated while maintaining the user
experience.
Extended Reduced-Form Framework for Non-Life Insurance
Authors: Francesca Biagini, Yinglin Zhang
Date: 2018-02-21 00:00:00
Tasks: Form

In this paper we propose a general framework for modeling an insurance liability cash flow in continuous time, by generalizing the reduced-form framework for credit risk and life insurance. In particular, we assume a nontrivial dependence structure between the reference filtration and the insurance internal filtration. We apply these results for pricing and hedging non-life insurance liabilities in hybrid financial and insurance markets, while taking into account the role of inflation under the benchmarked risk-minimization approach. This framework offers at the same time a general and flexible structure, and an explicit and treatable pricing-hedging formula.
The stationary distribution of a sample from the Wright-Fisher diffusion model with general small mutation rates
Date: 2018-10-30 00:00:00

The stationary distribution of a sample taken from a Wright-Fisher diffusion
with general small mutation rates is found using a coalescent approach. The
approximation is equivalent to having at most one mutation in the coalescent
tree to the first order in the rates. The sample probabilities characterize an
approximation for the stationary distribution from the Wright-Fisher diffusion.
The approach is different from Burden and Tang (2016,2017) who use a
probability flux argument to obtain the same results from a forward diffusion
generator equation. The solution has interest because the solution is not known
when rates are not small. An analogous solution is found for the configuration
of alleles in a general exchangeable binary coalescent tree. In particular an
explicit solution is found for a pure birth process tree when individuals
reproduce at rate lambda.
Closed-loop control of a modular neuromorphic biohybrid
Date: 2018-02-22 00:00:00
Tasks: Cultural Vocal Bursts Intensity Prediction

Neural networks modularity is a major challenge for the development of
control circuits of neural activity. Under physiological limitations, the
accessible regions for external stimulation are possibly different from the
functionally relevant ones, requiring complex indirect control designs.
Moreover, control over one region might affect activity of other downstream
networks, once sparse connections exist. We address these questions by
developing a hybrid device of a cortical culture functionally integrated with a
biomimetic hardware neural network. This design enables the study of modular
networks controllability, while connectivity is well-defined and key features
of cortical networks are accessible. Using a closed-loop control to monitor the
activity of the coupled hybrid, we show that both modules are congruently
modified, in the macroscopic as well as the microscopic activity levels.
Control impacts efficiently the activity on both sides whether the control
circuit is an indirect series one, or implemented independently only on one of
the modules. Hence, these results present global functional impacts of a local
control intervention. Overall, this strategy provides an experimental access to
the controllability of neural activity irregularities, when embedded in a
modular organization.
Synthesizing a Clock Signal with Reactions---Part I: Duty Cycle Implementation Based on Gears
Date: 2018-02-22 00:00:00

Timing is of fundamental importance in biology and our life. Borrowing ideas
from mechanism, we map our clock signals onto a gear system, in pursuit of
better depiction of a clock signal implemented with chemical reaction networks
(CRNs). On a chassis of gear theory, more quantitative descriptions are offered
for our method. Inspired by gears, our work to synthesize a tunable clock
signal could be divided into two parts. Part I, this paper, mainly focuses on
the implementation of clock signals with three types of duty cycles, namely
$1/2$, $1/N$ ($N > 2$), and $M/N$. Part II devotes itself in addressing
frequency alteration issues of clock signals. \textcolor{black}{Guaranteed by
existing literature, the experimental chassis can be taken care of by DNA
strand displacement reactions, which lay a solid foundation for the physical
implementation of nearly arbitrary CRNs.
Synthesizing a Clock Signal with Reactions---Part II: Frequency Alteration Based on Gears
Date: 2018-02-22 00:00:00

On a chassis of gear model, we have offered a quantitative description for
our method to synthesize a chemical clock signal with various duty cycles in
Part I. As Part II of the study, this paper devotes itself in proposing a
design methodology to handle frequency alteration issues for the chemical
clock, including both frequency division and frequency multiplication. Several
interesting examples are provided for a better explanation of our contribution.
All the simulation results verify and validate the correctness and efficiency
of our proposal.
Aspect-Aware Latent Factor Model: Rating Prediction with Ratings and Reviews
Authors: Cheng Zhiyong, Ding Ying, Zhu Lei, Kankanhalli Mohan
Date: 2018-02-22 00:00:00

Although latent factor models (e.g., matrix factorization) achieve good
accuracy in rating prediction, they suffer from several problems including
cold-start, non-transparency, and suboptimal recommendation for local users or
items. In this paper, we employ textual review information with ratings to
tackle these limitations. Firstly, we apply a proposed aspect-aware topic model
(ATM) on the review text to model user preferences and item features from
different aspects, and estimate the aspect importance of a user towards an
item. The aspect importance is then integrated into a novel aspect-aware latent
factor model (ALFM), which learns user's and item's latent factors based on
ratings. In particular, ALFM introduces a weighted matrix to associate those
latent factors with the same set of aspects discovered by ATM, such that the
latent factors could be used to estimate aspect ratings. Finally, the overall
rating is computed via a linear combination of the aspect ratings, which are
weighted by the corresponding aspect importance. To this end, our model could
alleviate the data sparsity problem and gain good interpretability for
recommendation. Besides, an aspect rating is weighted by an aspect importance,
which is dependent on the targeted user's preferences and targeted item's
features. Therefore, it is expected that the proposed method can model a user's
preferences on an item more accurately for each user-item pair locally.
Comprehensive experimental studies have been conducted on 19 datasets from
Amazon and Yelp 2017 Challenge dataset. Results show that our method achieves
significant improvement compared with strong baseline methods, especially for
users with only few ratings. Moreover, our model could interpret the
recommendation results in depth.