201 research outputs found
China is on the track tackling Enteromorpha spp forming green tide
Green tide management is supposed to be a long term fight rather than an episode during the 29th Olympic Games for China, since it has been gaining in scale and frequency during the past 3 decades in both marine and estuary environment all over the world. A number of rapid-responding studies including oceanographic comprehensive surveys along the coastline have been conducted during the bloom and post-bloom periods in 2008 by Chinese marine scientists. The preliminary results are as below: (1) phylogenetic analysis indicates that the bloom forming alga forms a clade with representatives of the green seaweed Enteromorpha linza, though, the alga has been identified as E. proliera by means of morphological; (2) the present data suggest that the bloom was originated from south of Yellow Sea, but not the severely affected area near Qingdao City; (3) pathways of reproduction for E. prolifera have approved to be multifarious, including sexual, asexual and vegetative propagation; (4) somatic cells may act as a propagule bank, which is supposed to be a very dangerous transmitting way for its marked movability, adaptability and viability; (5) pyrolysis of the alga showed that three stages appeared during the process, which are dehydration (18–20^o^C), main devolatilization (200–450^o^C) and residual decomposition (450–750^o^C), and activation energy of the alga was determined at 237.23 KJ•mol^-1^. Although the scarce knowlegde on E. prolifera not yet allow a fully understanding of the green tide, some of the results suggests possible directions in further green tide research and management
Link Prediction on Heterophilic Graphs via Disentangled Representation Learning
Link prediction is an important task that has wide applications in various
domains. However, the majority of existing link prediction approaches assume
the given graph follows homophily assumption, and designs similarity-based
heuristics or representation learning approaches to predict links. However,
many real-world graphs are heterophilic graphs, where the homophily assumption
does not hold, which challenges existing link prediction methods. Generally, in
heterophilic graphs, there are many latent factors causing the link formation,
and two linked nodes tend to be similar in one or two factors but might be
dissimilar in other factors, leading to low overall similarity. Thus, one way
is to learn disentangled representation for each node with each vector
capturing the latent representation of a node on one factor, which paves a way
to model the link formation in heterophilic graphs, resulting in better node
representation learning and link prediction performance. However, the work on
this is rather limited. Therefore, in this paper, we study a novel problem of
exploring disentangled representation learning for link prediction on
heterophilic graphs. We propose a novel framework DisenLink which can learn
disentangled representations by modeling the link formation and perform
factor-aware message-passing to facilitate link prediction. Extensive
experiments on 13 real-world datasets demonstrate the effectiveness of
DisenLink for link prediction on both heterophilic and hemophiliac graphs. Our
codes are available at https://github.com/sjz5202/DisenLin
Improving Fairness of Graph Neural Networks: A Graph Counterfactual Perspective
Graph neural networks have shown great ability in representation (GNNs)
learning on graphs, facilitating various tasks. Despite their great performance
in modeling graphs, recent works show that GNNs tend to inherit and amplify the
bias from training data, causing concerns of the adoption of GNNs in high-stake
scenarios. Hence, many efforts have been taken for fairness-aware GNNs.
However, most existing fair GNNs learn fair node representations by adopting
statistical fairness notions, which may fail to alleviate bias in the presence
of statistical anomalies. Motivated by causal theory, there are several
attempts utilizing graph counterfactual fairness to mitigate root causes of
unfairness. However, these methods suffer from non-realistic counterfactuals
obtained by perturbation or generation. In this paper, we take a causal view on
fair graph learning problem. Guided by the casual analysis, we propose a novel
framework CAF, which can select counterfactuals from training data to avoid
non-realistic counterfactuals and adopt selected counterfactuals to learn fair
node representations for node classification task. Extensive experiments on
synthetic and real-world datasets show the effectiveness of CAF
A Robust Planning Model for Offshore Microgrid Considering Tidal Power and Desalination
Increasing attention has been paid to resources on islands, thus microgrids
on islands need to be invested. Different from onshore microgrids, offshore
microgrids (OM) are usually abundant in ocean renewable energy (ORE), such as
offshore wind, tidal power generation (TPG), etc. Moreover, some special loads
such as seawater desalination unit (SDU) should be included. In this sense,
this paper proposes a planning method for OM to minimize the investment cost
while the ORE's fluctuation could be accommodated with robustness. First, a
deterministic planning model (DPM) is formulated for the OM with TPG and SDU. A
robust planning model (RPM) is then developed considering the uncertainties
from both TPG and load demand. The Column-and-constraint generation (C&CG)
algorithm is then employed to solve the RPM, producing planning results for the
OM that is robust against the worst scenario. Results of the case studies show
that the investment and operation decisions of the proposed model are robust,
and TPG shows good complementarity with the other RESs
- …