Decomposition-based Generation Process for Instance-Dependent Partial Label Learning

Partial label learning (PLL) is a typical weakly supervised learning problem, where each training example is associated with a set of candidate labels among which only one is true. Most existing PLL approaches assume that the incorrect labels in each training example are randomly picked as the candidate labels and model the generation process of the candidate labels in a simple way. However, these approaches usually do not perform as well as expected due to the fact that the generation process of the candidate labels is always instance-dependent. Therefore, it deserves to be modeled in a refined way. In this paper, we consider instance-dependent PLL and assume that the generation process of the candidate labels could decompose into two sequential parts, where the correct label emerges first in the mind of the annotator but then the incorrect labels related to the feature are also selected with the correct label as candidate labels due to uncertainty of labeling. Motivated by this consideration, we propose a novel PLL method that performs Maximum A Posterior(MAP) based on an explicitly modeled generation process of candidate labels via decomposed probability distribution models. Experiments on benchmark and real-world datasets validate the effectiveness of the proposed method

Parametric study of aerodynamic performance of equivalent ducted/un-ducted propellers based on high-fidelity computational fluid dynamics

Abstract not currently available

Fundamental understanding of thermophysical properties of molten salts containing nanoparticles

Molten salts have been widely used as thermal energy storage (TES) materials as they offer favourable specifications which enable them to be employed in TES applications. Finding a cost-effective method to enhance the energy storage capability of molten salts has caught the attention of many researchers. It was reported that by adding a small amount of nanoparticles, a major enhancement of the specific heat capacity was observed in molten salts. Though different studies argued that the enhancement was not found in other thermal storage materials, the observation of the enhancement was continuously reported. This work studied the thermal properties of molten salt based nanosuspensions synthesized with a novel method modified based on other studies. Molecular dynamics (MD) simulations were employed to study the thermodynamic properties of the nanosuspension systems. By the analysis of the effect on the internal energy of the nanosuspensions I draft general conclusions and explain why molten salt have this specific heat enhancement while other materials (e.g. water) does not. I use MD simulation to support, for the first time, a theory that can explain the apparently contradictory behaviour of the experimental data. Moreover, the main impact factor affecting the enhancement was investigated and discussed

Anticipation of Uncertain Threat Modulates Subsequent Affective Responses and Covariation Bias

Uncertainty contributes to stress and anxiety-like behaviors by impairing the ability of participants to objectively estimate threat. Our study used the cue-picture paradigm in conjunction with the event-related potential (ERP) technique to explore the temporal dynamics of anticipation for and response to uncertain threat in healthy individuals. This task used two types of cue. While ‘certain’ cues precisely forecasted the valence of the subsequent pictures (negative or neutral), the valence of pictures following ‘uncertain’ cues was not predictable. ERP data showed that, during anticipation, uncertain cues elicited similar Stimulus-Preceding Negativity (SPN) to certain-negative cues, while both of them elicited larger SPN than certain-neutral cues. During affective processing, uncertainty enlarged the mean amplitude of late positive potential (LPP) for both negative and neutral pictures. Behavioral data showed that participants reported more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures and overestimated the probability of negative pictures following uncertain cues. Importantly, the enlarged anticipatory activity evoked by uncertain cues relative to that evoked by certain-neutral cues positively modulated the more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures. Further, this more negative mood ratings and the general arousal anticipation during anticipatory stage contributed to the covariation bias. These results can provide a novel insight into understanding the neural mechanism and pathological basis of anxiety

Numerical simulation of distributed propulsion systems using CFD

This paper examines a Distributed Propulsion (DP) concept and involves CFD verification, optimisation and evaluation. The first part of the study validates the employed simulation methods using experimental data from the NASA Workshop for Integrated Propeller Prediction (WIPP) and the Folding Conformal High Lift Propeller (HLP) project, for isolated and installed cases under various conditions. Additionally, validation for rotor-rotor interactions was also conducted using the GARTEUR Action Group 26 measurements. The second part of the paper examines installed propeller configurations to identify performance differences based on their position relative to a lifting wing. The results indicate that distributed propellers with small radii interfere more with the wing, than tip-mounted, large propellers. Additionally, propeller and wing performance vary with respect to the propeller installation location. The propeller in tractor configuration showed higher efficiency than the over-the-wing (OTW) configuration by about 7%. However, results from this work showed a 2% improvement in the propeller efficiency when the OTW configuration had a pylon installed. This study also found that optimising the propeller from a tractor to OTW configuration, significantly improved the wing performance. At take-off and landing, the Lift-to-Drag (L/D) ratio of the OTW configuration almost quadrupled, and the overall propulsive efficiency increased by about 5%. The simulations showed that the OTW configuration with different numbers of propellers, outperformed the tractor configurations with the same number of propellers. Furthermore, up to 26% improvement in lift and overall propulsive efficiency was found by introducing the DP system in the OTW configuration