3,148 research outputs found
The electronic structure and magnetic interactions in the mixed transition-metal oxide La(Co,Ni)O3 studied by x-ray absorption spectroscopies
XAS findet klare Hinweise auf einen gemischtvalenten Zustand für Co ebenso wie für Ni. Während der allmähliche Spinübergang von Co3+ von einem Niedrigspin-Zustand hin zu einem Hochspin-Zustand für geringe Dotierungsgrade x erhalten bleibt. Insbesondere finden wir, dass es die Koexistenz des HS-Zustandes sowohl in Co3+ als auch in Ni3+ sein muß, die zu der verantwortlichen ferromagnetischen Wechselwirkung führt
CasGCN: Predicting future cascade growth based on information diffusion graph
Sudden bursts of information cascades can lead to unexpected consequences
such as extreme opinions, changes in fashion trends, and uncontrollable spread
of rumors. It has become an important problem on how to effectively predict a
cascade' size in the future, especially for large-scale cascades on social
media platforms such as Twitter and Weibo. However, existing methods are
insufficient in dealing with this challenging prediction problem. Conventional
methods heavily rely on either hand crafted features or unrealistic
assumptions. End-to-end deep learning models, such as recurrent neural
networks, are not suitable to work with graphical inputs directly and cannot
handle structural information that is embedded in the cascade graphs. In this
paper, we propose a novel deep learning architecture for cascade growth
prediction, called CasGCN, which employs the graph convolutional network to
extract structural features from a graphical input, followed by the application
of the attention mechanism on both the extracted features and the temporal
information before conducting cascade size prediction. We conduct experiments
on two real-world cascade growth prediction scenarios (i.e., retweet popularity
on Sina Weibo and academic paper citations on DBLP), with the experimental
results showing that CasGCN enjoys a superior performance over several baseline
methods, particularly when the cascades are of large scale
On Large Language Models' Selection Bias in Multi-Choice Questions
Multi-choice questions (MCQs) serve as a common yet important task format in
the research of large language models (LLMs). Our work shows that LLMs exhibit
an inherent "selection bias" in MCQs, which refers to LLMs' preferences to
select options located at specific positions (like "Option C"). This bias is
prevalent across various LLMs, making their performance vulnerable to option
position changes in MCQs. We identify that one primary cause resulting in
selection bias is option numbering, i.e., the ID symbols A/B/C/D associated
with the options. To mitigate selection bias, we propose a new method called
PriDe. PriDe first decomposes the observed model prediction distribution into
an intrinsic prediction over option contents and a prior distribution over
option IDs. It then estimates the prior by permutating option contents on a
small number of test samples, which is used to debias the subsequent test
samples. We demonstrate that, as a label-free, inference-time method, PriDe
achieves a more effective and computation-efficient debiasing than strong
baselines. We further show that the priors estimated by PriDe generalize well
across different domains, highlighting its practical potential in broader
scenarios.Comment: Work in progress. 21 pages, 13 figure
Optimal integration of mobile battery energy storage in distribution system with renewables
published_or_final_versio
Observational constraints on cosmic neutrinos and dark energy revisited
Using several cosmological observations, i.e. the cosmic microwave background
anisotropies (WMAP), the weak gravitational lensing (CFHTLS), the measurements
of baryon acoustic oscillations (SDSS+WiggleZ), the most recent observational
Hubble parameter data, the Union2.1 compilation of type Ia supernovae, and the
HST prior, we impose constraints on the sum of neutrino masses (\mnu), the
effective number of neutrino species (\neff) and dark energy equation of
state (), individually and collectively. We find that a tight upper limit on
\mnu can be extracted from the full data combination, if \neff and are
fixed. However this upper bound is severely weakened if \neff and are
allowed to vary. This result naturally raises questions on the robustness of
previous strict upper bounds on \mnu, ever reported in the literature. The
best-fit values from our most generalized constraint read
\mnu=0.556^{+0.231}_{-0.288}\rm eV, \neff=3.839\pm0.452, and
at 68% confidence level, which shows a firm lower limit on
total neutrino mass, favors an extra light degree of freedom, and supports the
cosmological constant model. The current weak lensing data are already helpful
in constraining cosmological model parameters for fixed . The dataset of
Hubble parameter gains numerous advantages over supernovae when ,
particularly its illuminating power in constraining \neff. As long as is
included as a free parameter, it is still the standardizable candles of type Ia
supernovae that play the most dominant role in the parameter constraints.Comment: 39 pages, 15 figures, 7 tables, accepted to JCA
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