214 research outputs found
Towards Joint Electricity and Data Trading: A Scalable Cooperative Game Theoretic Approach
This paper, for the first time, proposes a joint electricity and data trading
mechanism based on cooperative game theory. All prosumers first submit the
parameters associated with both electricity and data to the market operator.
The operator utilizes the public and prosumers' private data to forecast the
distributed renewable generators (DRGs) and quantify the improvement driven by
prosumers' private data in terms of reduced uncertainty set. Then, the operator
maximizes the grand coalition's total payoff considering the uncertain
generation of DRGs and imputes the payoff to each prosumer based on their
contribution to electricity and data sharing. The mathematical formulation of
the grand coalition is developed and converted into a second order cone
programming problem by using an affinepolicy based robust approach. The
stability of such a grand coalition is mathematically proved, i.e., all
prosumers are willing to cooperate. Furthermore, to address the scalability
challenge of existing payoff imputation methods in the cooperative game, a two
stage optimization based approach is proposed, which is converted into a mixed
integer second order cone programming and solved by the Benders decomposition.
Case studies illustrate all prosumers are motivated to trade electricity and
data under the joint trading framework and the proposed imputation method
significantly enhances the scalability
Hurricanes on tidally locked terrestrial planets: Fixed surface temperature experiments
In this work, we study the presence of hurricanes on exoplanets. Tidally
locked terrestrial planets around M dwarfs are the main targets of space
missions looking to discover habitable exoplanets. The question of whether
hurricanes can form on this kind of planet is important for determining their
climate and habitability. Using a high-resolution global atmospheric
circulation model, we investigated whether there are hurricanes on tidally
locked terrestrial planets under fixed surface temperatures. The relevant
effects of the planetary rotation rate, surface temperature, and bulk
atmospheric compositions were examined. We find that hurricanes can form on the
planets but not on all of them. For planets near the inner edge of the
habitable zone of late M dwarfs, there are more numerous and stronger
hurricanes on both day and night sides. For planets in the middle and outer
ranges of the habitable zone, the possibility of hurricane formation is low or
even close to zero, as has been suggested in recent studies. Earth-based
hurricane theories are applicable to tidally locked planets only when the
atmospheric compositions are similar to that of Earth. However, if the
background atmosphere is lighter than H2O, hurricanes can hardly be produced
because convection is always inhibited due to the effect of the mean molecular
weight, similarly to the case of Saturn. These results have broad implications
on the precipitation, ocean mixing, climate, and atmospheric characterization
of tidally locked planets. Finally, A test with a coupled slab ocean and an
Earth-like atmosphere in a tide-locked orbit of ten Earth days demonstrates
that there are also hurricanes present in the experiment
Prevalence of allergic rhinitis among adults in urban and rural areas of China : a population-based cross-sectional survey
Purpose: The aim of the present study was to compare the prevalence of self-reported and confirmable allergic rhinitis (AR) with positive skin prick test (SPT) results among adults living in urban and rural areas of China.
Methods: Adults from a community in Beijing and a village in Baoding were selected as representative urban and rural dwellers, respectively. All eligible residents were enrolled from the population register and received a face-to-face interview using modified validated questionnaires. Equal sets of randomly selected self-reporting AR-positive and AR-negative participants who responded to the questionnaires were also investigated using skin prick tests.
Results: A total of 803 participants in the rural area and a total of 1,499 participants in the urban area completed the questionnaires, with response rates being 75.9% and 81.5% respectively. The prevalence of self-reported AR of the rural area (19.1%) was significantly higher than that of the urban area (13.5%). The elementary school of educational level increased the risk of having AR (adjusted OR=2.198, 95% CI=1.072-2.236). The positive SET rates among subjects with self-reported AR in the rural and urban areas were 32.5% and 53.3%, respectively; the confirmable AR prevalence of 6.2% and 7.2% among the rural and urban adults, respectively.
Conclusions: The prevalence of confirmable AR is similar between rural and urban areas in China, although there is a higher prevalence of self-reported AR in the former
Cyber-physical interdependent restoration scheduling for active distribution network via ad hoc wireless communication
This paper proposes a post-disaster cyber-physical interdependent restoration
scheduling (CPIRS) framework for active distribution networks (ADN) where the
simultaneous damages on cyber and physical networks are considered. The ad hoc
wireless device-to-device (D2D) communication is leveraged, for the first time,
to establish cyber networks instantly after the disaster to support ADN
restoration. The repair and operation crew dispatching, the remote-controlled
network reconfiguration and the system operation with DERs can be effectively
coordinated under the cyber-physical interactions. The uncertain outputs of
renewable energy resources (RESs) are represented by budget-constrained
polyhedral uncertainty sets. Through implementing linearization techniques on
disjunctive expressions, a monolithic mixed-integer linear programming (MILP)
based two-stage robust optimization model is formulated and subsequently solved
by a customized column-and-constraint generation (C&CG) algorithm. Numerical
results on the IEEE 123-node distribution system demonstrate the effectiveness
and superiorities of the proposed CPIRS method for ADN
Simple and Efficient Heterogeneous Graph Neural Network
Heterogeneous graph neural networks (HGNNs) have powerful capability to embed
rich structural and semantic information of a heterogeneous graph into node
representations. Existing HGNNs inherit many mechanisms from graph neural
networks (GNNs) over homogeneous graphs, especially the attention mechanism and
the multi-layer structure. These mechanisms bring excessive complexity, but
seldom work studies whether they are really effective on heterogeneous graphs.
This paper conducts an in-depth and detailed study of these mechanisms and
proposes Simple and Efficient Heterogeneous Graph Neural Network (SeHGNN). To
easily capture structural information, SeHGNN pre-computes the neighbor
aggregation using a light-weight mean aggregator, which reduces complexity by
removing overused neighbor attention and avoiding repeated neighbor aggregation
in every training epoch. To better utilize semantic information, SeHGNN adopts
the single-layer structure with long metapaths to extend the receptive field,
as well as a transformer-based semantic fusion module to fuse features from
different metapaths. As a result, SeHGNN exhibits the characteristics of simple
network structure, high prediction accuracy, and fast training speed. Extensive
experiments on five real-world heterogeneous graphs demonstrate the superiority
of SeHGNN over the state-of-the-arts on both accuracy and training speed.Comment: Accepted by AAAI 202
Implementing a new fully stepwise decomposition-based sampling technique for the hybrid water level forecasting model in real-world application
Various time variant non-stationary signals need to be pre-processed properly
in hydrological time series forecasting in real world, for example, predictions
of water level. Decomposition method is a good candidate and widely used in
such a pre-processing problem. However, decomposition methods with an
inappropriate sampling technique may introduce future data which is not
available in practical applications, and result in incorrect
decomposition-based forecasting models. In this work, a novel Fully Stepwise
Decomposition-Based (FSDB) sampling technique is well designed for the
decomposition-based forecasting model, strictly avoiding introducing future
information. This sampling technique with decomposition methods, such as
Variational Mode Decomposition (VMD) and Singular spectrum analysis (SSA), is
applied to predict water level time series in three different stations of
Guoyang and Chaohu basins in China. Results of VMD-based hybrid model using
FSDB sampling technique show that Nash-Sutcliffe Efficiency (NSE) coefficient
is increased by 6.4%, 28.8% and 7.0% in three stations respectively, compared
with those obtained from the currently most advanced sampling technique. In the
meantime, for series of SSA-based experiments, NSE is increased by 3.2%, 3.1%
and 1.1% respectively. We conclude that the newly developed FSDB sampling
technique can be used to enhance the performance of decomposition-based hybrid
model in water level time series forecasting in real world
Intelligent ZHENG Classification of Hypertension Depending on ML-kNN and Information Fusion
Hypertension is one of the major causes of heart cerebrovascular diseases. With a good accumulation of hypertension clinical data on hand, research on hypertension's ZHENG differentiation is an important and attractive topic, as Traditional Chinese Medicine (TCM) lies primarily in “treatment based on ZHENG differentiation.” From the view of data mining, ZHENG differentiation is modeled as a classification problem. In this paper, ML-kNN—a multilabel learning model—is used as the classification model for hypertension. Feature-level information fusion is also used for further utilization of all information. Experiment results show that ML-kNN can model the hypertension's ZHENG differentiation well. Information fusion helps improve models' performance
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