12 research outputs found
Interaction Pattern Disentangling for Multi-Agent Reinforcement Learning
Deep cooperative multi-agent reinforcement learning has demonstrated its
remarkable success over a wide spectrum of complex control tasks. However,
recent advances in multi-agent learning mainly focus on value decomposition
while leaving entity interactions still intertwined, which easily leads to
over-fitting on noisy interactions between entities. In this work, we introduce
a novel interactiOn Pattern disenTangling (OPT) method, to disentangle not only
the joint value function into agent-wise value functions for decentralized
execution, but also the entity interactions into interaction prototypes, each
of which represents an underlying interaction pattern within a subgroup of the
entities. OPT facilitates filtering the noisy interactions between irrelevant
entities and thus significantly improves generalizability as well as
interpretability. Specifically, OPT introduces a sparse disagreement mechanism
to encourage sparsity and diversity among discovered interaction prototypes.
Then the model selectively restructures these prototypes into a compact
interaction pattern by an aggregator with learnable weights. To alleviate the
training instability issue caused by partial observability, we propose to
maximize the mutual information between the aggregation weights and the history
behaviors of each agent. Experiments on both single-task and multi-task
benchmarks demonstrate that the proposed method yields results superior to the
state-of-the-art counterparts. Our code is available at
https://github.com/liushunyu/OPT
Contrastive Identity-Aware Learning for Multi-Agent Value Decomposition
Value Decomposition (VD) aims to deduce the contributions of agents for
decentralized policies in the presence of only global rewards, and has recently
emerged as a powerful credit assignment paradigm for tackling cooperative
Multi-Agent Reinforcement Learning (MARL) problems. One of the main challenges
in VD is to promote diverse behaviors among agents, while existing methods
directly encourage the diversity of learned agent networks with various
strategies. However, we argue that these dedicated designs for agent networks
are still limited by the indistinguishable VD network, leading to homogeneous
agent behaviors and thus downgrading the cooperation capability. In this paper,
we propose a novel Contrastive Identity-Aware learning (CIA) method, explicitly
boosting the credit-level distinguishability of the VD network to break the
bottleneck of multi-agent diversity. Specifically, our approach leverages
contrastive learning to maximize the mutual information between the temporal
credits and identity representations of different agents, encouraging the full
expressiveness of credit assignment and further the emergence of
individualities. The algorithm implementation of the proposed CIA module is
simple yet effective that can be readily incorporated into various VD
architectures. Experiments on the SMAC benchmarks and across different VD
backbones demonstrate that the proposed method yields results superior to the
state-of-the-art counterparts. Our code is available at
https://github.com/liushunyu/CIA
Complete mitochondrial genome sequence and phylogenetic analysis of the Taiwan tai Argyrops bleekeri (Spariformes: Sparidae)
In this study, the complete mitochondrial genome of the Taiwan tai Argyrops bleekeri was determined for the first time by next-generation sequencing. The circular mtDNA molecule was 16,646 bp in size and the overall base composition was A (27.77%), C (28.95%), G (16.60%), and T (26.68%), with a slight bias toward A + T. The complete mitogenome encoded 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. Phylogenetic analysis based on the 13 PCGs of the Sparidae family revealed that Argyrops appears to be most closely related to Pagrus and Parargyrops, but further research is needed
Spatiotemporal-Augmented Graph Neural Networks for Human Mobility Simulation
Human mobility patterns have shown significant applications in
policy-decision scenarios and economic behavior researches. The human mobility
simulation task aims to generate human mobility trajectories given a small set
of trajectory data, which have aroused much concern due to the scarcity and
sparsity of human mobility data. Existing methods mostly rely on the static
relationships of locations, while largely neglect the dynamic spatiotemporal
effects of locations. On the one hand, spatiotemporal correspondences of visit
distributions reveal the spatial proximity and the functionality similarity of
locations. On the other hand, the varying durations in different locations
hinder the iterative generation process of the mobility trajectory. Therefore,
we propose a novel framework to model the dynamic spatiotemporal effects of
locations, namely SpatioTemporal-Augmented gRaph neural networks (STAR). The
STAR framework designs various spatiotemporal graphs to capture the
spatiotemporal correspondences and builds a novel dwell branch to simulate the
varying durations in locations, which is finally optimized in an adversarial
manner. The comprehensive experiments over four real datasets for the human
mobility simulation have verified the superiority of STAR to state-of-the-art
methods. Our code will be made publicly available
Visual Boundary Knowledge Translation for Foreground Segmentation
When confronted with objects of unknown types in an image, humans can effortlessly and precisely tell their visual boundaries. This recognition mechanism and underlying generalization capability seem to contrast to state-of-the-art image segmentation networks that rely on large-scale category-aware annotated training samples. In this paper, we make an attempt towards building models that explicitly account for visual boundary knowledge, in hope to reduce the training effort on segmenting unseen categories. Specifically, we investigate a new task termed as Boundary Knowledge Translation (BKT). Given a set of fully labeled categories, BKT aims to translate the visual boundary knowledge learned from the labeled categories, to a set of novel categories, each of which is provided only a few labeled samples.
To this end, we propose a Translation Segmentation Network (Trans-Net), which comprises a segmentation network and two boundary discriminators. The segmentation network, combined with a boundary-aware self-supervised mechanism, is devised to conduct foreground segmentation, while the two discriminators work together in an adversarial manner to ensure an accurate segmentation of the novel categories under light supervision. Exhaustive experiments demonstrate that, with only tens of labeled samples as guidance, Trans-Net achieves close results on par with fully supervised methods
Ask-AC: An Initiative Advisor-in-the-Loop Actor-Critic Framework
Despite the promising results achieved, state-of-the-art interactive
reinforcement learning schemes rely on passively receiving supervision signals
from advisor experts, in the form of either continuous monitoring or
pre-defined rules, which inevitably result in a cumbersome and expensive
learning process. In this paper, we introduce a novel initiative
advisor-in-the-loop actor-critic framework, termed as Ask-AC, that replaces the
unilateral advisor-guidance mechanism with a bidirectional learner-initiative
one, and thereby enables a customized and efficacious message exchange between
learner and advisor. At the heart of Ask-AC are two complementary components,
namely action requester and adaptive state selector, that can be readily
incorporated into various discrete actor-critic architectures. The former
component allows the agent to initiatively seek advisor intervention in the
presence of uncertain states, while the latter identifies the unstable states
potentially missed by the former especially when environment changes, and then
learns to promote the ask action on such states. Experimental results on both
stationary and non-stationary environments and across different actor-critic
backbones demonstrate that the proposed framework significantly improves the
learning efficiency of the agent, and achieves the performances on par with
those obtained by continuous advisor monitoring
Distribution-Aware Graph Representation Learning for Transient Stability Assessment of Power System
The real-time transient stability assessment (TSA) plays a critical role in
the secure operation of the power system. Although the classic numerical
integration method, \textit{i.e.} time-domain simulation (TDS), has been widely
used in industry practice, it is inevitably trapped in a high computational
complexity due to the high latitude sophistication of the power system. In this
work, a data-driven power system estimation method is proposed to quickly
predict the stability of the power system before TDS reaches the end of
simulating time windows, which can reduce the average simulation time of
stability assessment without loss of accuracy. As the topology of the power
system is in the form of graph structure, graph neural network based
representation learning is naturally suitable for learning the status of the
power system. Motivated by observing the distribution information of crucial
active power and reactive power on the power system's bus nodes, we thus
propose a distribution-aware learning~(DAL) module to explore an informative
graph representation vector for describing the status of a power system. Then,
TSA is re-defined as a binary classification task, and the stability of the
system is determined directly from the resulting graph representation without
numerical integration. Finally, we apply our method to the online TSA task. The
case studies on the IEEE 39-bus system and Polish 2383-bus system demonstrate
the effectiveness of our proposed method.Comment: 8 pages, 6 figures, 4 table
Larval Spatiotemporal Distribution of Six Fish Species: Implications for Sustainable Fisheries Management in the East China Sea
The larval distributions of the small-sized fishes Omobranchus elegans, Erisphex pottii, Benthosema pterotum, Acropoma japonicum, Upeneus bensasi, and Apogonichthys lineatus in the East China Sea ecosystem are important due to their ecological and economic benefits. To date, however, there have been few studies describing their population distributions and dynamics. In the current study, ichthyoplankton surveys were carried out from April to July 2018 to analyze variations in the larval abundance, distribution, and development stages of these species. In addition, the spatiotemporal larval distribution was investigated in terms of measured environmental variables. It was found that larvae were mainly distributed at depths of 5.00–66.00 m, in areas with sea surface temperature of 4.40–29.60 °C, sea surface salinity of 16.54–34.60 psu, pH of 7.00–9.00, and dissolved oxygen concentration of 2.54–8.70 mg/L. Benthosema pterotum and A. lineatus migrated from 30.00–31.00° N 123.17–123.50° E in June to 30.00–32.50° N 122.22–123.50° E in July. The results of this study can help to preserve spawning and nursery grounds and contribute to sustainable coastal fisheries management
Larval Spatiotemporal Distribution of Six Fish Species: Implications for Sustainable Fisheries Management in the East China Sea
The larval distributions of the small-sized fishes Omobranchus elegans, Erisphex pottii, Benthosema pterotum, Acropoma japonicum, Upeneus bensasi, and Apogonichthys lineatus in the East China Sea ecosystem are important due to their ecological and economic benefits. To date, however, there have been few studies describing their population distributions and dynamics. In the current study, ichthyoplankton surveys were carried out from April to July 2018 to analyze variations in the larval abundance, distribution, and development stages of these species. In addition, the spatiotemporal larval distribution was investigated in terms of measured environmental variables. It was found that larvae were mainly distributed at depths of 5.00–66.00 m, in areas with sea surface temperature of 4.40–29.60 °C, sea surface salinity of 16.54–34.60 psu, pH of 7.00–9.00, and dissolved oxygen concentration of 2.54–8.70 mg/L. Benthosema pterotum and A. lineatus migrated from 30.00–31.00° N 123.17–123.50° E in June to 30.00–32.50° N 122.22–123.50° E in July. The results of this study can help to preserve spawning and nursery grounds and contribute to sustainable coastal fisheries management