103 research outputs found
Numerical analyses of the flow past a short rotating cylinder
This work studies the three-dimensional flow dynamics around a rotating
circular cylinder of finite length, whose axis is positioned perpendicular to
the streamwise direction. Direct numerical simulations and global stability
analyses are performed within a parameter range of Reynolds number
(based on cylinder diameter , uniform incoming flow
velocity ), length-to-diameter ratio and dimensionless
rotation rate (where is rotation
rate). By solving Nav\-ier--Sto\-kes equations, we investigated the wake
patterns and explored the phase diagrams of the lift and drag coefficients. For
a cylinder with , we found that when the rotation effect is weak
(), the wake pattern is similar to the unsteady wake
past the non-rotating finite-length cylinder, but with a new linear unstable
mode competing to dominate the saturation state of the wake. The flow becomes
stable for when . When the rotation
effect is strong (), new low-frequency wake patterns with
stronger oscillations emerge. Furthermore, the stability analyses based on the
time-averaged flows and on the steady solutions demonstrate the existence of
multiple unstable modes undergoing Hopf bifurcation, greatly influenced by the
rotation effect. The shapes of these global eigenmodes are presented and
compared, as well as their structural sensitivity, visualising the flow region
important for the disturbance development with rotation. This research
contributes to our understanding of the complex bluff-body wake dynamics past
this critical configuration.Comment: 35 pages, 29 figures, the version of record of this article is
accepted in Journal of Fluid Mechanic
Prompting GPT-3 To Be Reliable
Large language models (LLMs) show impressive abilities via few-shot
prompting. Commercialized APIs such as OpenAI GPT-3 further increase their use
in real-world language applications. However, the crucial problem of how to
improve the reliability of GPT-3 is still under-explored. While reliability is
a broad and vaguely defined term, we decompose reliability into four main
facets that correspond to the existing framework of ML safety and are
well-recognized to be important: generalizability, social biases, calibration,
and factuality. Our core contribution is to establish simple and effective
prompts that improve GPT-3's reliability as it: 1) generalizes
out-of-distribution, 2) balances demographic distribution and uses natural
language instructions to reduce social biases, 3) calibrates output
probabilities, and 4) updates the LLM's factual knowledge and reasoning chains.
With appropriate prompts, GPT-3 is more reliable than smaller-scale supervised
models on all these facets. We release all processed datasets, evaluation
scripts, and model predictions. Our systematic empirical study not only sheds
new insights on the reliability of prompting LLMs, but more importantly, our
prompting strategies can help practitioners more reliably use LLMs like GPT-3.Comment: ICLR 202
Intelligent Exploration for User Interface Modules of Mobile App with Collective Learning
A mobile app interface usually consists of a set of user interface modules.
How to properly design these user interface modules is vital to achieving user
satisfaction for a mobile app. However, there are few methods to determine
design variables for user interface modules except for relying on the judgment
of designers. Usually, a laborious post-processing step is necessary to verify
the key change of each design variable. Therefore, there is a only very limited
amount of design solutions that can be tested. It is timeconsuming and almost
impossible to figure out the best design solutions as there are many modules.
To this end, we introduce FEELER, a framework to fast and intelligently explore
design solutions of user interface modules with a collective machine learning
approach. FEELER can help designers quantitatively measure the preference score
of different design solutions, aiming to facilitate the designers to
conveniently and quickly adjust user interface module. We conducted extensive
experimental evaluations on two real-life datasets to demonstrate its
applicability in real-life cases of user interface module design in the Baidu
App, which is one of the most popular mobile apps in China.Comment: 10 pages, accepted as a full paper in KDD 202
Simulation of tumor ablation in hyperthermia cancer treatment: A parametric study
A holistic simulation framework is established on magnetic hyperthermia
modeling to solve the treatment process of tumor, which is surrounded by a
healthy tissue block. The interstitial tissue fluid, MNP distribution,
temperature profile, and nanofluids are involved in the simulation. Study
evaluates the cancer treatment efficacy by cumulative-equivalent-minutes-at-43
centigrade (CEM43), a widely accepted thermal dose coming from the cell death
curve. Results are separated into the conditions of with or without gravity
effect in the computational domain, where two baseline case are investigated
and compared. An optimal treatment time 46.55 min happens in the baseline case
without gravity, but the situation deteriorates with gravity effect where the
time for totally killing tumor cells prolongs 36.11% and meanwhile causing
21.32% ablation in healthy tissue. For the cases without gravity, parameter
study of Lewis number and Heat source number are conducted and the variation of
optimal treatment time are both fitting to the inverse functions. For the case
considering the gravity, parameters Buoyancy ratio and Darcy ratio are
investigated and their influence on totally killing tumor cells and the injury
on healthy tissue are matching with the parabolic functions. The results are
beneficial to the prediction of various conditions, and provides useful guide
to the magnetic hyperthermia treatment
Effect of Mst1 on Endometriosis Apoptosis and Migration: Role of Drp1-Related Mitochondrial Fission and Parkin-Required Mitophagy
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