577 research outputs found
Distributed Traffic Signal Control for Maximum Network Throughput
We propose a distributed algorithm for controlling traffic signals. Our
algorithm is adapted from backpressure routing, which has been mainly applied
to communication and power networks. We formally prove that our algorithm
ensures global optimality as it leads to maximum network throughput even though
the controller is constructed and implemented in a completely distributed
manner. Simulation results show that our algorithm significantly outperforms
SCATS, an adaptive traffic signal control system that is being used in many
cities
Optimal Selective Harmonic Control for Power Harmonics Mitigation
This paper proposes an Internal Model Principle (IMP) based optimal Selective Harmonic Controller (SHC) for power converters to mitigate power harmonics. According to the harmonics distribution caused by power converters, a universal recursive SHC module is developed to deal with a featured group of power harmonics. The proposed optimal SHC is of hybrid structure: all recursive SHC modules with weighted gains are connected in parallel. It bridges the real “nk+-m order RC” and the complex “parallel structure RC”. Compared to other IMP based control solutions, it offers an optimal trade-off among the cost, the complexity and the performance: high accuracy, fast transient response, easy-implementation, cost-effective, and also easy-to-design. The analysis and synthesis of the optimal SHC system are addressed. The proposed SHC offers power convert-ers a tailor-made optimal control solution for compensating selected harmonic frequencies. Application examples of grid-connected inverters confirm the effectiveness of the proposed control scheme
Shenzhen’s Policies on Intangible Cultural Heritage Inheritance and Practices of Digital Dissemination
This paper examines the protection and transmission of intangible cultural heritage in sports dance within Shenzhen, focusing on specific practices such as the Longgang Dragon Dance, Bao'an Qilin Dance, Longgang Qilin Dance, and Nanshan Yi Dance. Through comprehensive field investigations and direct interviews, it explores the current state of intangible cultural heritage preservation and transmission in Shenzhen. The analysis details the implementation of relevant policies and identifies that the potential contributions of online communities and grassroots organizations in promoting the conservation and inheritance of these cultural forms remain underexploited. The study proposes that heritage custodians more systematically leverage digital technologies to enhance the propagation of intangible cultural heritage. This, in turn, will foster the high-quality development of Shenzhen's cultural heritage
Towards Real-World Aerial Vision Guidance with Categorical 6D Pose Tracker
Tracking the object 6-DoF pose is crucial for various downstream robot tasks
and real-world applications. In this paper, we investigate the real-world robot
task of aerial vision guidance for aerial robotics manipulation, utilizing
category-level 6-DoF pose tracking. Aerial conditions inevitably introduce
special challenges, such as rapid viewpoint changes in pitch and roll and
inter-frame differences. To support these challenges in task, we firstly
introduce a robust category-level 6-DoF pose tracker (Robust6DoF). This tracker
leverages shape and temporal prior knowledge to explore optimal inter-frame
keypoint pairs, generated under a priori structural adaptive supervision in a
coarse-to-fine manner. Notably, our Robust6DoF employs a Spatial-Temporal
Augmentation module to deal with the problems of the inter-frame differences
and intra-class shape variations through both temporal dynamic filtering and
shape-similarity filtering. We further present a Pose-Aware Discrete Servo
strategy (PAD-Servo), serving as a decoupling approach to implement the final
aerial vision guidance task. It contains two servo action policies to better
accommodate the structural properties of aerial robotics manipulation.
Exhaustive experiments on four well-known public benchmarks demonstrate the
superiority of our Robust6DoF. Real-world tests directly verify that our
Robust6DoF along with PAD-Servo can be readily used in real-world aerial
robotic applications
A passive repetitive controller for discrete-time finite-frequency positive-real systems
This work proposes and studies a new internal model for discrete-time passive or finite-frequency positive-real systems which can be used in repetitive control designs to track or to attenuate periodic signals. The main characteristic of the proposed internal model is its passivity. This property implies closed-loop stability when it is used with discrete-time passive plants, as well as the broader class of discrete-time finite-frequency positive real plants. This work discusses the internal model energy function and its frequency response. A design procedure for repetitive controllers based on the proposed internal model is also presented. Two numerical examples are included.Peer Reviewe
A new passive repetitive controller for discrete-time finite-frequency positive-real systems
This work proposes a new repetitive controller for discrete-time finite-frequency positive-real systems which are required to track periodic references or to attenuate periodic disturbances. The main characteristic of the proposed controller is its passivity. This fact implies closed-loop stable behavior when it is used with discrete-time passive plants, but additional conditions must be fulfilled when it is used with a discretetime finite-frequency positive-real plant. These conditions are analyzed and a design procedure is proposed.Peer Reviewe
NeSLAM: Neural Implicit Mapping and Self-Supervised Feature Tracking With Depth Completion and Denoising
In recent years, there have been significant advancements in 3D
reconstruction and dense RGB-D SLAM systems. One notable development is the
application of Neural Radiance Fields (NeRF) in these systems, which utilizes
implicit neural representation to encode 3D scenes. This extension of NeRF to
SLAM has shown promising results. However, the depth images obtained from
consumer-grade RGB-D sensors are often sparse and noisy, which poses
significant challenges for 3D reconstruction and affects the accuracy of the
representation of the scene geometry. Moreover, the original hierarchical
feature grid with occupancy value is inaccurate for scene geometry
representation. Furthermore, the existing methods select random pixels for
camera tracking, which leads to inaccurate localization and is not robust in
real-world indoor environments. To this end, we present NeSLAM, an advanced
framework that achieves accurate and dense depth estimation, robust camera
tracking, and realistic synthesis of novel views. First, a depth completion and
denoising network is designed to provide dense geometry prior and guide the
neural implicit representation optimization. Second, the occupancy scene
representation is replaced with Signed Distance Field (SDF) hierarchical scene
representation for high-quality reconstruction and view synthesis. Furthermore,
we also propose a NeRF-based self-supervised feature tracking algorithm for
robust real-time tracking. Experiments on various indoor datasets demonstrate
the effectiveness and accuracy of the system in reconstruction, tracking
quality, and novel view synthesis
ProSGNeRF: Progressive Dynamic Neural Scene Graph with Frequency Modulated Auto-Encoder in Urban Scenes
Implicit neural representation has demonstrated promising results in view
synthesis for large and complex scenes. However, existing approaches either
fail to capture the fast-moving objects or need to build the scene graph
without camera ego-motions, leading to low-quality synthesized views of the
scene. We aim to jointly solve the view synthesis problem of large-scale urban
scenes and fast-moving vehicles, which is more practical and challenging. To
this end, we first leverage a graph structure to learn the local scene
representations of dynamic objects and the background. Then, we design a
progressive scheme that dynamically allocates a new local scene graph trained
with frames within a temporal window, allowing us to scale up the
representation to an arbitrarily large scene. Besides, the training views of
urban scenes are relatively sparse, which leads to a significant decline in
reconstruction accuracy for dynamic objects. Therefore, we design a frequency
auto-encoder network to encode the latent code and regularize the frequency
range of objects, which can enhance the representation of dynamic objects and
address the issue of sparse image inputs. Additionally, we employ lidar point
projection to maintain geometry consistency in large-scale urban scenes.
Experimental results demonstrate that our method achieves state-of-the-art view
synthesis accuracy, object manipulation, and scene roaming ability. The code
will be open-sourced upon paper acceptance
Magnetic-Assisted Initialization for Infrastructure-free Mobile Robot Localization
Most of the existing mobile robot localization solutions are either heavily
dependent on pre-installed infrastructures or having difficulty working in
highly repetitive environments which do not have sufficient unique features. To
address this problem, we propose a magnetic-assisted initialization approach
that enhances the performance of infrastructure-free mobile robot localization
in repetitive featureless environments. The proposed system adopts a
coarse-to-fine structure, which mainly consists of two parts: magnetic
field-based matching and laser scan matching. Firstly, the interpolated
magnetic field map is built and the initial pose of the mobile robot is partly
determined by the k-Nearest Neighbors (k-NN) algorithm. Next, with the fusion
of prior initial pose information, the robot is localized by laser scan
matching more accurately and efficiently. In our experiment, the mobile robot
was successfully localized in a featureless rectangular corridor with a success
rate of 88% and an average correct localization time of 6.6 seconds
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