94 research outputs found
Care for the Land: Restoration as Interspecies Care Labor and Emergent Activism at the Hawaiian Fishpond-scape
In the last two decades, environmental NGOs on the islands of Hawai’I have been leading efforts to restore traditional land practices and foodways, among them fishpond, or loko i’a, which are traditional aquaculture infrastructures that ensure a stable production of fish protein. This ethnographic study of loko i’a restoration projects is informed by four months of fieldwork grounded in participant observation at Paepae O He’eia, a non-profit organization on the windward side of O’ahu heading the restorative effort at He’eia fishpond.
My thesis addresses the ethics of care, labor, and Indigenous worldmaking emerging from ecological and cultural restoration of fishponds that have been neglected and disrepaired due to colonialism and climate disasters. The project explores fishpond restoration at He’eia to understand their centrality for community building for all beings, for human and other-than human actors, as well as creating more expansive frameworks of Indigenous sovereignty and activism. By investigating the role and contradictions of environmental “care” practices, I illuminate multispecies collaborative survival, resistance, and Indigenous world-making practices in the age of the Anthropocene
Application of nonparametric regression in predicting traffic incident duration
Predicting the duration time of incidents is important for effective real-time Traffic Incident Management (TIM). In the current study, the k-Nearest Neighbor (kNN) algorithm is employed as a nonparametric regression approach to develop a traffic incident duration prediction model. Incident data from 2008 on the third ring expressway mainline in Beijing are collected from the local Incident Reporting and Dispatching System. The incident sites are randomly distributed along the mainline, which is 48.3 km long and has six two-way lanes with a single-lane daily volume of more than 10000 veh. The main incident type used is sideswipe and the average incident duration time is 32.69 min. The most recent one-fourth of the incident records are selected as testing set. Vivatrat method is employed to filter anomalous data for the training set. Incident duration time is set as the dependent variable in Kruskal–Wallis test, and six attributes are identified as the main factors that affect the length of duration time, which are ‘day first shift’, ‘weekday’, ‘incident type’, ‘congestion’, ‘incident grade’ and ‘distance’. Based on the characteristics of duration time distribution, log transformation of original data is tested and proven to improve model performance. Different distance metrics and prediction algorithms are carefully investigated. Results demonstrate that the kNN model has better prediction accuracy using weighted distance metric based on decision tree and weighted prediction algorithm. The developed prediction model is further compared with other models based on the same dataset. Results show that the developed model can obtain reasonable prediction results, except for samples with extremely short or long duration. Such a prediction model can help TIM teams estimate the incident duration and implement real-time incident management strategies.
First published online 28 January 201
Quantum-inspired Complex Convolutional Neural Networks
Quantum-inspired neural network is one of the interesting researches at the
junction of the two fields of quantum computing and deep learning. Several
models of quantum-inspired neurons with real parameters have been proposed,
which are mainly used for three-layer feedforward neural networks. In this
work, we improve the quantum-inspired neurons by exploiting the complex-valued
weights which have richer representational capacity and better non-linearity.
We then extend the method of implementing the quantum-inspired neurons to the
convolutional operations, and naturally draw the models of quantum-inspired
convolutional neural networks (QICNNs) capable of processing high-dimensional
data. Five specific structures of QICNNs are discussed which are different in
the way of implementing the convolutional and fully connected layers. The
performance of classification accuracy of the five QICNNs are tested on the
MNIST and CIFAR-10 datasets. The results show that the QICNNs can perform
better in classification accuracy on MNIST dataset than the classical CNN. More
learning tasks that our QICNN can outperform the classical counterparts will be
found.Comment: 12pages, 6 figure
A Fully Data-Driven Approach for Realistic Traffic Signal Control Using Offline Reinforcement Learning
The optimization of traffic signal control (TSC) is critical for an efficient
transportation system. In recent years, reinforcement learning (RL) techniques
have emerged as a popular approach for TSC and show promising results for
highly adaptive control. However, existing RL-based methods suffer from notably
poor real-world applicability and hardly have any successful deployments. The
reasons for such failures are mostly due to the reliance on over-idealized
traffic simulators for policy optimization, as well as using unrealistic
fine-grained state observations and reward signals that are not directly
obtainable from real-world sensors. In this paper, we propose a fully
Data-Driven and simulator-free framework for realistic Traffic Signal Control
(D2TSC). Specifically, we combine well-established traffic flow theory with
machine learning to construct a reward inference model to infer the reward
signals from coarse-grained traffic data. With the inferred rewards, we further
propose a sample-efficient offline RL method to enable direct signal control
policy learning from historical offline datasets of real-world intersections.
To evaluate our approach, we collect historical traffic data from a real-world
intersection, and develop a highly customized simulation environment that
strictly follows real data characteristics. We demonstrate through extensive
experiments that our approach achieves superior performance over conventional
and offline RL baselines, and also enjoys much better real-world applicability.Comment: 15 pages, 6 figure
Optimization and Noise Analysis of the Quantum Algorithm for Solving One-Dimensional Poisson Equation
Solving differential equations is one of the most promising applications of
quantum computing. Recently we proposed an efficient quantum algorithm for
solving one-dimensional Poisson equation avoiding the need to perform quantum
arithmetic or Hamiltonian simulation. In this letter, we further develop this
algorithm to make it closer to the real application on the noisy
intermediate-scale quantum (NISQ) devices. To this end, we first develop a new
way of performing the sine transformation, and based on it the algorithm is
optimized by reducing the depth of the circuit from n2 to n. Then, we analyze
the effect of common noise existing in the real quantum devices on our
algorithm using the IBM Qiskit toolkit. We find that the phase damping noise
has little effect on our algorithm, while the bit flip noise has the greatest
impact. In addition, threshold errors of the quantum gates are obtained to make
the fidelity of the circuit output being greater than 90%. The results of noise
analysis will provide a good guidance for the subsequent work of error
mitigation and error correction for our algorithm. The noise-analysis method
developed in this work can be used for other algorithms to be executed on the
NISQ devices.Comment: 20 pages, 9 figure
Dual-axis illumination for virtually augmenting the detection view of optical-resolution photoacoustic microscopy
Optical-resolution photoacoustic microscopy (OR-PAM) has demonstrated fast, label-free volumetric imaging of optical-absorption contrast within the quasiballistic regime of photon scattering. However, the limited numerical aperture of the ultrasonic transducer restricts the detectability of the photoacoustic waves, thus resulting in incomplete reconstructed features. To tackle the limited-view problem, we added an oblique illumination beam to the original coaxial optical-acoustic scheme to provide a complementary detection view. The virtual augmentation of the detection view was validated through numerical simulations and tissue-phantom experiments. More importantly, the combination of top and oblique illumination successfully imaged a mouse brain in vivo down to 1 mm in depth, showing detailed brain vasculature. Of special note, it clearly revealed the diving vessels that were long missing in images from original OR-PAM
Black-Box Quantum State Preparation with Inverse Coefficients
Black-box quantum state preparation is a fundamental building block for many
higher-level quantum algorithms, which is applied to transduce the data from
computational basis into amplitude. Here we present a new algorithm for
performing black-box state preparation with inverse coefficients based on the
technique of inequality test. This algorithm can be used as a subroutine to
perform the controlled rotation stage of the Harrow-Hassidim-Lloyd (HHL)
algorithm and the associated matrix inversion algorithms with exceedingly low
cost. Furthermore, we extend this approach to address the general black-box
state preparation problem where the transduced coefficient is a general
non-linear function. The present algorithm greatly relieves the need to do
arithmetic and the error is only resulted from the truncated error of binary
string. It is expected that our algorithm will find wide usage both in the NISQ
and fault-tolerant quantum algorithms.Comment: 11 pages, 3 figure
Hybrid quantum-classical convolutional neural network for phytoplankton classification
The taxonomic composition and abundance of phytoplankton have a direct impact on marine ecosystem dynamics and global environment change. Phytoplankton classification is crucial for phytoplankton analysis, but it is challenging due to their large quantity and small size. Machine learning is the primary method for automatically performing phytoplankton image classification. As large-scale research on marine phytoplankton generates overwhelming amounts of data, more powerful computational resources are required for the success of machine learning methods. Recently, quantum machine learning has emerged as a potential solution for large-scale data processing by harnessing the exponentially computational power of quantum computers. Here, for the first time, we demonstrate the feasibility of using quantum deep neural networks for phytoplankton classification. Hybrid quantum-classical convolutional and residual neural networks are developed based on the classical architectures. These models strike a balance between the limited function of current quantum devices and the large size of phytoplankton images, making it possible to perform phytoplankton classification on near-term quantum computers. Our quantum models demonstrate superior performance compared to their classical counterparts, exhibiting faster convergence, higher classification accuracy and lower accuracy fluctuation. The present quantum models are versatile and can be applied to various tasks of image classification in the field of marine science
BoostTree and BoostForest for Ensemble Learning
Bootstrap aggregating (Bagging) and boosting are two popular ensemble
learning approaches, which combine multiple base learners to generate a
composite model for more accurate and more reliable performance. They have been
widely used in biology, engineering, healthcare, etc. This article proposes
BoostForest, which is an ensemble learning approach using BoostTree as base
learners and can be used for both classification and regression. BoostTree
constructs a tree model by gradient boosting. It achieves high randomness
(diversity) by sampling its parameters randomly from a parameter pool, and
selecting a subset of features randomly at node splitting. BoostForest further
increases the randomness by bootstrapping the training data in constructing
different BoostTrees. BoostForest outperformed four classical ensemble learning
approaches (Random Forest, Extra-Trees, XGBoost and LightGBM) on 34
classification and regression datasets. Remarkably, BoostForest has only one
hyper-parameter (the number of BoostTrees), which can be easily specified. Our
code is publicly available, and the proposed ensemble learning framework can
also be used to combine many other base learners
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