28 research outputs found
A DRL-based Reflection Enhancement Method for RIS-assisted Multi-receiver Communications
In reconfigurable intelligent surface (RIS)-assisted wireless communication
systems, the pointing accuracy and intensity of reflections depend crucially on
the 'profile,' representing the amplitude/phase state information of all
elements in a RIS array. The superposition of multiple single-reflection
profiles enables multi-reflection for distributed users. However, the
optimization challenges from periodic element arrangements in single-reflection
and multi-reflection profiles are understudied. The combination of periodical
single-reflection profiles leads to amplitude/phase counteractions, affecting
the performance of each reflection beam. This paper focuses on a
dual-reflection optimization scenario and investigates the far-field
performance deterioration caused by the misalignment of overlapped profiles. To
address this issue, we introduce a novel deep reinforcement learning
(DRL)-based optimization method. Comparative experiments against random and
exhaustive searches demonstrate that our proposed DRL method outperforms both
alternatives, achieving the shortest optimization time. Remarkably, our
approach achieves a 1.2 dB gain in the reflection peak gain and a broader beam
without any hardware modifications.Comment: 6 pages, 6 figures. This paper has been accepted for presentation at
the VTC2023-Fal
RLOps:Development Life-cycle of Reinforcement Learning Aided Open RAN
Radio access network (RAN) technologies continue to witness massive growth,
with Open RAN gaining the most recent momentum. In the O-RAN specifications,
the RAN intelligent controller (RIC) serves as an automation host. This article
introduces principles for machine learning (ML), in particular, reinforcement
learning (RL) relevant for the O-RAN stack. Furthermore, we review
state-of-the-art research in wireless networks and cast it onto the RAN
framework and the hierarchy of the O-RAN architecture. We provide a taxonomy of
the challenges faced by ML/RL models throughout the development life-cycle:
from the system specification to production deployment (data acquisition, model
design, testing and management, etc.). To address the challenges, we integrate
a set of existing MLOps principles with unique characteristics when RL agents
are considered. This paper discusses a systematic life-cycle model development,
testing and validation pipeline, termed: RLOps. We discuss all fundamental
parts of RLOps, which include: model specification, development and
distillation, production environment serving, operations monitoring,
safety/security and data engineering platform. Based on these principles, we
propose the best practices for RLOps to achieve an automated and reproducible
model development process.Comment: 17 pages, 6 figrue
Distributed Sensing, Computing, Communication, and Control Fabric: A Unified Service-Level Architecture for 6G
With the advent of the multimodal immersive communication system, people can
interact with each other using multiple devices for sensing, communication
and/or control either onsite or remotely. As a breakthrough concept, a
distributed sensing, computing, communications, and control (DS3C) fabric is
introduced in this paper for provisioning 6G services in multi-tenant
environments in a unified manner. The DS3C fabric can be further enhanced by
natively incorporating intelligent algorithms for network automation and
managing networking, computing, and sensing resources efficiently to serve
vertical use cases with extreme and/or conflicting requirements. As such, the
paper proposes a novel end-to-end 6G system architecture with enhanced
intelligence spanning across different network, computing, and business
domains, identifies vertical use cases and presents an overview of the relevant
standardization and pre-standardization landscape
Identification of pyroptosis-related subtypes and establishment of prognostic model and immune characteristics in asthma
BackgroundAlthough studies have shown that cell pyroptosis is involved in the progression of asthma, a systematic analysis of the clinical significance of pyroptosis-related genes (PRGs) cooperating with immune cells in asthma patients is still lacking.MethodsTranscriptome sequencing datasets from patients with different disease courses were used to screen pyroptosis-related differentially expressed genes and perform biological function analysis. Clustering based on K-means unsupervised clustering method is performed to identify pyroptosis-related subtypes in asthma and explore biological functional characteristics of poorly controlled subtypes. Diagnostic markers between subtypes were screened and validated using an asthma mouse model. The infiltration of immune cells in airway epithelium was evaluated based on CIBERSORT, and the correlation between diagnostic markers and immune cells was analyzed. Finally, a risk prediction model was established and experimentally verified using differentially expressed genes between pyroptosis subtypes in combination with asthma control. The cMAP database and molecular docking were utilized to predict potential therapeutic drugs.ResultsNineteen differentially expressed PRGs and two subtypes were identified between patients with mild-to-moderate and severe asthma conditions. Significant differences were observed in asthma control and FEV1 reversibility between the two subtypes. Poor control subtypes were closely related to glucocorticoid resistance and airway remodeling. BNIP3 was identified as a diagnostic marker and associated with immune cell infiltration such as, M2 macrophages. The risk prediction model containing four genes has accurate classification efficiency and prediction value. Small molecules obtained from the cMAP database that may have therapeutic effects on asthma are mainly DPP4 inhibitors.ConclusionPyroptosis and its mediated immune phenotype are crucial in the occurrence, development, and prognosis of asthma. The predictive models and drugs developed on the basis of PRGs may provide new solutions for the management of asthma
Design and Optimization of a Liquid Cooling Thermal Management System with Flow Distributors and Spiral Channel Cooling Plates for Lithium-Ion Batteries
In this study, a three-dimensional transient simulation model of a liquid cooling thermal management system with flow distributors and spiral channel cooling plates for pouch lithium-ion batteries has been developed. The cooling plates play the role of uniforming temperature distribution and reducing the maximum temperature within each battery, while the flow distributors have the function of reducing the temperature difference between batteries in the battery module. The accuracy of the thermophysical properties and heat generation rate of the battery was verified experimentally. The optimal structure and cooling strategy of the system was determined by single factor analysis as well as orthogonal test and matrix analysis methods. The optimal solution resulted in a maximum battery module temperature of 34.65 °C, a maximum temperature difference of 3.95 °C, and a channel pressure drop of 8.82 Pa. Using the world-harmonized light-duty vehicles test cycle (WLTC) conditions for a battery pack in an electric car, the performance of the optimal battery thermal management system (BTMS) design was tested, and the results indicate that the maximum temperature can be controlled below 25.51 °C and the maximum temperature difference below 0.21 °C, which well meet the requirements of BTMS designs
Bayesian Optimisation-Assisted Neural Network Training Technique for Radio Localisation
Radio signal-based (indoor) localisation technique is important for IoT
applications such as smart factory and warehouse. Through machine learning,
especially neural networks methods, more accurate mapping from signal features
to target positions can be achieved. However, different radio protocols, such
as WiFi, Bluetooth, etc., have different features in the transmitted signals
that can be exploited for localisation purposes. Also, neural networks methods
often rely on carefully configured models and extensive training processes to
obtain satisfactory performance in individual localisation scenarios. The above
poses a major challenge in the process of determining neural network model
structure, or hyperparameters, as well as the selection of training features
from the available data. This paper proposes a neural network model
hyperparameter tuning and training method based on Bayesian optimisation.
Adaptive selection of model hyperparameters and training features can be
realised with minimal need for manual model training design. With the proposed
technique, the training process is optimised in a more automatic and efficient
way, enhancing the applicability of neural networks in localisation.Comment: 5 pages, 4 figures. This paper has been accepted for presentation at
the VTC2022-Sprin
Study on Hydrodynamic Characteristics of Wind Turbine Monopile under Nonlinear Wave
As wind power technologies become maturer, the monopile foundation of offshore wind turbine is widely used because of its simple structure, few occupied space and low cost. However, under severe sea conditions, the impact of nonlinear wave load applied against the monopile foundation on the system structure safety cannot be ignored. In this paper, the 5MW offshore wind turbine of the National Renewable Energy Laboratory (NREL) was taken as the research object, and the computational fluid analysis software ‘STARCCM +’ was used to study the hydrodynamic characteristics of the monopile foundation of the wind turbine under different wave parameters. This paper mainly analyzed the upper wave, pressure and wave forces around the monopile foundation of the wind turbine under the same period and different wave heights. And the wave force calculated by CFD was compared with the result based on potential flow theory. The research results showed that with the rise of wave height, the upper wave, pressure and wave force around the monopile foundation increase continuously, and the second-peak phenomenon appeared at some measuring points on the water surface of the monopile foundation. Because the CFD method considers the fluid viscosity and is more in line with the real sea conditions, it is more accurate to obtain wave forces based on this method