171 research outputs found
Investment Portfolio Strategies Based On Options Market Activity
We propose a multiple regression model that incorporates options market activity to forecast future stock prices. To capture the information content from the options market, we use a predictor based on the activity of call and put options as measured by relative open interest across available strike prices. We use a sample of stocks with actively traded options on the Chicago Board Options Exchange to test the model. Investment strategies that use these forecasts are shown to be superior to more simple strategies which ignore options market activity
Quality of PIN estimates and the PIN-return relationship
Keywords: Probability of informed trading PIN-return relationship Quality of PIN estimates a b s t r a c t This paper provides new evidence concerning the probability of informed trading (PIN) and the PIN-return relationship. We take measures to overcome known estimation biases and improve the quality of quarterly PIN estimates. We use the average of a firm's PIN estimates in four consecutive quarters to smooth out the effect of seasonal variation in trading activities. We find that when high-quality PIN estimates are used, the Fama-MacBeth cross-sectional regressions show stronger evidence for the positive PIN-return relationship than documented in the prior literature. This finding is robust to controls for the January, liquidity, and momentum effects
Exploring the Common Appearance-Boundary Adaptation for Nighttime Optical Flow
We investigate a challenging task of nighttime optical flow, which suffers
from weakened texture and amplified noise. These degradations weaken
discriminative visual features, thus causing invalid motion feature matching.
Typically, existing methods employ domain adaptation to transfer knowledge from
auxiliary domain to nighttime domain in either input visual space or output
motion space. However, this direct adaptation is ineffective, since there
exists a large domain gap due to the intrinsic heterogeneous nature of the
feature representations between auxiliary and nighttime domains. To overcome
this issue, we explore a common-latent space as the intermediate bridge to
reinforce the feature alignment between auxiliary and nighttime domains. In
this work, we exploit two auxiliary daytime and event domains, and propose a
novel common appearance-boundary adaptation framework for nighttime optical
flow. In appearance adaptation, we employ the intrinsic image decomposition to
embed the auxiliary daytime image and the nighttime image into a
reflectance-aligned common space. We discover that motion distributions of the
two reflectance maps are very similar, benefiting us to consistently transfer
motion appearance knowledge from daytime to nighttime domain. In boundary
adaptation, we theoretically derive the motion correlation formula between
nighttime image and accumulated events within a spatiotemporal gradient-aligned
common space. We figure out that the correlation of the two spatiotemporal
gradient maps shares significant discrepancy, benefitting us to contrastively
transfer boundary knowledge from event to nighttime domain. Moreover,
appearance adaptation and boundary adaptation are complementary to each other,
since they could jointly transfer global motion and local boundary knowledge to
the nighttime domain
Contactless Haptic Display Through Magnetic Field Control
Haptic rendering enables people to touch, perceive, and manipulate virtual
objects in a virtual environment. Using six cascaded identical hollow disk
electromagnets and a small permanent magnet attached to an operator's finger,
this paper proposes and develops an untethered haptic interface through
magnetic field control. The concentric hole inside the six cascaded
electromagnets provides the workspace, where the 3D position of the permanent
magnet is tracked with a Microsoft Kinect sensor. The driving currents of six
cascaded electromagnets are calculated in real-time for generating the desired
magnetic force. Offline data from an FEA (finite element analysis) based
simulation, determines the relationship between the magnetic force, the driving
currents, and the position of the permanent magnet. A set of experiments
including the virtual object recognition experiment, the virtual surface
identification experiment, and the user perception evaluation experiment were
conducted to demonstrate the proposed system, where Microsoft HoloLens
holographic glasses are used for visual rendering. The proposed magnetic haptic
display leads to an untethered and non-contact interface for natural haptic
rendering applications, which overcomes the constraints of mechanical linkages
in tool-based traditional haptic devices
Two hAT transposon genes were transferred from Brassicaceae to broomrapes and are actively expressed in some recipients
A growing body of evidence is pointing to an important role of horizontal gene transfer (HGT) in the evolution of higher plants. However, reports of HGTs of transposable elements (TEs) in plants are still scarce, and only one case is known of a class II transposon horizontally transferred between grasses. To investigate possible TE transfers in dicots, we performed transcriptome screening in the obligate root parasite Phelipanche aegyptiaca (Orobanchaceae), data-mining in the draft genome assemblies of four other Orobanchaceae, gene cloning, gene annotation in species with genomic information, and a molecular phylogenetic analysis. We discovered that the broomrape genera Phelipanche and Orobanche acquired two related nuclear genes (christened BO transposase genes), a new group of the hAT superfamily of class II transposons, from Asian Sisymbrieae or a closely related tribe of Brassicaceae, by HGT. The collinearity of the flanking genes, lack of a classic border structure, and low expression levels suggest that BO transposase genes cannot transpose in Brassicaceae, whereas they are highly expressed in P. aegyptiaca
Frame Pairwise Distance Loss for Weakly-supervised Sound Event Detection
Weakly-supervised learning has emerged as a promising approach to leverage
limited labeled data in various domains by bridging the gap between fully
supervised methods and unsupervised techniques. Acquisition of strong
annotations for detecting sound events is prohibitively expensive, making
weakly supervised learning a more cost-effective and broadly applicable
alternative. In order to enhance the recognition rate of the learning of
detection of weakly-supervised sound events, we introduce a Frame Pairwise
Distance (FPD) loss branch, complemented with a minimal amount of synthesized
data. The corresponding sampling and label processing strategies are also
proposed. Two distinct distance metrics are employed to evaluate the proposed
approach. Finally, the method is validated on the DCASE 2023 task4 dataset. The
obtained experimental results corroborated the efficacy of this approach.Comment: Submitted to ICASSP 202
A Theoretical Analysis of Efficiency Constrained Utility-Privacy Bi-Objective Optimization in Federated Learning
Federated learning (FL) enables multiple clients to collaboratively learn a
shared model without sharing their individual data. Concerns about utility,
privacy, and training efficiency in FL have garnered significant research
attention. Differential privacy has emerged as a prevalent technique in FL,
safeguarding the privacy of individual user data while impacting utility and
training efficiency. Within Differential Privacy Federated Learning (DPFL),
previous studies have primarily focused on the utility-privacy trade-off,
neglecting training efficiency, which is crucial for timely completion.
Moreover, differential privacy achieves privacy by introducing controlled
randomness (noise) on selected clients in each communication round. Previous
work has mainly examined the impact of noise level () and communication
rounds () on the privacy-utility dynamic, overlooking other influential
factors like the sample ratio (, the proportion of selected clients). This
paper systematically formulates an efficiency-constrained utility-privacy
bi-objective optimization problem in DPFL, focusing on , , and .
We provide a comprehensive theoretical analysis, yielding analytical solutions
for the Pareto front. Extensive empirical experiments verify the validity and
efficacy of our analysis, offering valuable guidance for low-cost parameter
design in DPFL
Molecular Characterization of the 14-3-3 Gene Family in Brachypodium distachyon L. Reveals High Evolutionary Conservation and Diverse Responses to Abiotic Stresses
The 14-3-3 gene family identified in all eukaryotic organisms is involved in a wide range of biological processes, particularly in resistance to various abiotic stresses. Here, we performed the first comprehensive study on the molecular characterisation, phylogenetics and responses to various abiotic stresses of the 14-3-3 gene family in Brachypodium distachyon L.. A total of seven 14-3-3 genes from B. distachyon and 120 from five main lineages among 12 species were identified, which were divided into five well-conserved subfamilies. The molecular structure analysis showed that the plant 14-3-3 gene family is highly evolutionarily conserved, although certain divergence had occurred in different subfamilies. The duplication event investigation revealed that segmental duplication seemed to be the predominant form by which the 14-3-3 gene family had expanded. Moreover, seven critical amino acids were detected, which may contribute to functional divergence. Expression profiling analysis showed that BdGF14 genes were abundantly expressed in the roots, but showed low expression in the meristems. All seven BdGF14 genes showed significant expression changes under various abiotic stresses, including heavy metal, phytohormone, osmotic, and temperature stresses, which might play important roles in responses to multiple abiotic stresses mainly through participating in ABA-dependent signalling and reactive oxygen species-mediated MAPK cascade signalling pathways. In particular, BdGF14 genes generally showed upregulated expression in response to multiple stresses of high temperature, heavy metal, abscisic acid (ABA), and salicylic acid (SA), but downregulated expression under H2O2, NaCl, and polyethylene glycol (PEG) stresses. Meanwhile, dynamic transcriptional expression analysis of BdGF14 genes under longer treatments with heavy metals (Cd2+, Cr3+, Cu2+, and Zn2+) and phytohormone (ABA) and recovery revealed two main expression trends in both roots and leaves: up-down and up-down-up expression from stress treatments to recovery. This study provides new insights into the structures and functions of plant 14-3-3 genes
- …