69 research outputs found
A general introduction to lithium-ion batteries: From the first concept to the top six commercials and beyond
The birth of lithium-ion batteries (LIBs) is not a breakthrough scientific discovery overnight but a successor and continuous development of scientists for a long time based on the previous generation of electrochemical batteries. The development of LIBs and succeeding generations of batteries, however, is highly hopeful given the broad commercialization of LIBs during the previous ten years. Intensified research is required to create next-generation LIBs with drastically better performance, including enhanced energy density, charging rate, lifespan, stability, and safety, in order to fulfill the rising demand for energy storage. Research into LIBs and next-generation is currently in an explosive phase with the goal of overcoming the significant challenge posed by conventional LIBs that can keep up with the rapidly evolving needs of the electronics, mechanical, and automation industries, particularly electric vehicles. In this case, this tutorial review might offer a broad overview of LIBs as well as an optimistic look toward the upcoming generation
Building a P2P RDF Store for Edge Devices
The Semantic Web technologies have been used in the Internet of Things (IoT)
to facilitate data interoperability and address data heterogeneity issues. The
Resource Description Framework (RDF) model is employed in the integration of
IoT data, with RDF engines serving as gateways for semantic integration.
However, storing and querying RDF data obtained from distributed sources across
a dynamic network of edge devices presents a challenging task. The distributed
nature of the edge shares similarities with Peer-to-Peer (P2P) systems. These
similarities include attributes like node heterogeneity, limited availability,
and resources. The nodes primarily undertake tasks related to data storage and
processing. Therefore, the P2P models appear to present an attractive approach
for constructing distributed RDF stores. Based on P-Grid, a data indexing
mechanism for load balancing and range query processing in P2P systems, this
paper proposes a design for storing and sharing RDF data on P2P networks of
low-cost edge devices. Our design aims to integrate both P-Grid and an
edge-based RDF storage solution, RDF4Led for building an P2P RDF engine. This
integration can maintain RDF data access and query processing while scaling
with increasing data and network size. We demonstrated the scaling behavior of
our implementation on a P2P network, involving up to 16 nodes of Raspberry Pi 4
devices.Comment: Accepted to IoT Conference 202
Semantic Programming for Device-Edge-Cloud Continuum
This position paper presents ThothSP, a Semantic Programming framework with
the aim of lowering the coding effort in building smart applications on the
Device-Edge-Cloud continuum by leveraging semantic knowledge. It introduces a
novel neural-symbolic stream fusion mechanism, which enables the specification
of data fusion pipelines via declarative rules, with degrees of learnable
probabilistic weights. Moreover, it includes an adaptive federator that allows
the Thoth>runtime to be distributed across multiple compute nodes in a network,
and to coordinate their resources to collaboratively process tasks by
delegating partial workloads to their peers. To demonstrate ThothSP's
capability, we report a case study on a distributed camera network to show
ThothSP's behaviour against a traditional edge-cloud setup.Comment: arXiv admin note: text overlap with arXiv:2202.1395
An Efficient Design of the Piezoresistive Pressure Sensor Applied for Micro Aerial Vehicle
In this research, the developing process of a piezoresistive pressure sensor working in the atmosphere environment applied in micro aerial vehicle using the MEMS fabrication method is introduced. The sensor consists of four Au/Cr piezoresistors in a Wheatstone bridge configuration on a wet oxidized silicon diaphragm. To fabricate the sensor, three lithographic steps were conducted: the first one is to define the resistors and Au/Cr lines/pads, the second and the third ones are to determine the width and the thickness of the square SiO2/Si diaphragm, respectively. The sensor diaphragm shape and thickness were defined by the anisotropic etching of Si in tetramethylammonium hydroxide (TMAH) solution, and the resistors array are formed by sputtering and wet etching method. The sensor size is ~6000 µm by 6000 µm. The sensor output voltage was measured for various applied pressure levels from 0 to 1.2 bar with 5V voltage supply. The fabricated sensor also exhibits a sensitivity of 50.01 mV/bar
An Efficient Design of the Piezoresistive Pressure Sensor Applied for Micro Aerial Vehicle
In this research, the developing process of a piezoresistive pressure sensor working in the atmosphere environment applied in micro aerial vehicle using the MEMS fabrication method is introduced. The sensor consists of four Au/Cr piezoresistors in a Wheatstone bridge configuration on a wet oxidized silicon diaphragm. To fabricate the sensor, three lithographic steps were conducted: the first one is to define the resistors and Au/Cr lines/pads, the second and the third ones are to determine the width and the thickness of the square SiO2/Si diaphragm, respectively. The sensor diaphragm shape and thickness were defined by the anisotropic etching of Si in tetramethylammonium hydroxide (TMAH) solution, and the resistors array are formed by sputtering and wet etching method. The sensor size is ~6000 µm by 6000 µm. The sensor output voltage was measured for various applied pressure levels from 0 to 1.2 bar with 5V voltage supply. The fabricated sensor also exhibits a sensitivity of 50.01 mV/bar
Pushing the Scalability of RDF Engines on IoT Edge Devices
Semantic interoperability for the Internet of Things (IoT) is enabled by standards and technologies from the Semantic Web. As recent research suggests a move towards decentralised IoT architectures, we have investigated the scalability and robustness of RDF (Resource Description Framework)engines that can be embedded throughout the architecture, in particular at edge nodes. RDF processing at the edge facilitates the deployment of semantic integration gateways closer to low-level devices. Our focus is on how to enable scalable and robust RDF engines that can operate on lightweight devices. In this paper, we have first carried out an empirical study of the scalability and behaviour of solutions for RDF data management on standard computing hardware that have been ported to run on lightweight devices at the network edge. The findings of our study shows that these RDF store solutions have several shortcomings on commodity ARM (Advanced RISC Machine) boards that are representative of IoT edge node hardware. Consequently, this has inspired us to introduce a lightweight RDF engine, which comprises an RDF storage and a SPARQL processor for lightweight edge devices, called RDF4Led. RDF4Led follows the RISC-style (Reduce Instruction Set Computer) design philosophy. The design constitutes a flash-aware storage structure, an indexing scheme, an alternative buffer management technique and a low-memory-footprint join algorithm that demonstrates improved scalability and robustness over competing solutions. With a significantly smaller memory footprint, we show that RDF4Led can handle 2 to 5 times more data than popular RDF engines such as Jena TDB (Tuple Database) and RDF4J, while consuming the same amount of memory. In particular, RDF4Led requires 10%–30% memory of its competitors to operate on datasets of up to 50 million triples. On memory-constrained ARM boards, it can perform faster updates and can scale better than Jena TDB and Virtuoso. Furthermore, we demonstrate considerably faster query operations than Jena TDB and RDF4J.BMBF, 01IS18025A, Verbundprojekt BIFOLD-BBDC: Berlin Institute for the Foundations of Learning and DataBMBF, 01IS18037A, Verbundprojekt BIFOLD-BZML: Berlin Institute for the Foundations of Learning and DataEC/H2020/661180/EU/A Scalable and Elastic Platform for Near-Realtime Analytics for The Graph of Everything/SMARTE
VisionKG: Unleashing the Power of Visual Datasets via Knowledge Graph
The availability of vast amounts of visual data with heterogeneous features
is a key factor for developing, testing, and benchmarking of new computer
vision (CV) algorithms and architectures. Most visual datasets are created and
curated for specific tasks or with limited image data distribution for very
specific situations, and there is no unified approach to manage and access them
across diverse sources, tasks, and taxonomies. This not only creates
unnecessary overheads when building robust visual recognition systems, but also
introduces biases into learning systems and limits the capabilities of
data-centric AI. To address these problems, we propose the Vision Knowledge
Graph (VisionKG), a novel resource that interlinks, organizes and manages
visual datasets via knowledge graphs and Semantic Web technologies. It can
serve as a unified framework facilitating simple access and querying of
state-of-the-art visual datasets, regardless of their heterogeneous formats and
taxonomies. One of the key differences between our approach and existing
methods is that ours is knowledge-based rather than metadatabased. It enhances
the enrichment of the semantics at both image and instance levels and offers
various data retrieval and exploratory services via SPARQL. VisionKG currently
contains 519 million RDF triples that describe approximately 40 million
entities, and are accessible at https://vision.semkg.org and through APIs. With
the integration of 30 datasets and four popular CV tasks, we demonstrate its
usefulness across various scenarios when working with CV pipelines
ANNOUNCEMENT OF THE SUSTAINABLE DEVELOPMENT REPORT OF VIETNAMESE HOTEL ENTERPRISES
The purpose of this study is to examine the factors affecting the publication of sustainability reports from the
perspective of managers at 4-5 star hotels in Vietnam. Issues of corporate size, profitability, legal regulation, corporate
governance and technology of the company were mentioned as factors that may affect the publication of the report on
sustainable development. The author has synthesized the relevant background theory as well as previous outstanding studies
on the issue of publishing sustainable development reports. SPSS 20 software was used to test the relationship between the
factors affecting the publication of the Sustainable Development Report based on the manager's point of view. The results of
the study show that the factors of business size, profitability, and legal regulations all affect the publication of sustainable
development reports at 4-5 star hotels in Vietnam. A new finding of this study is that the two factors of corporate governance
and the company's technology combine into a public governance factor based on technology and it is the technology that has
the strongest influence on the publication of the Sustainable Development Report. The study once again confirms the
relationship between the factors affecting the publication of the Sustainable Development Report and is a document to help
researchers understand better in the research context in Vietnam, one of the leading countries in the world developing
countries and have limited access to and use of secondary data
PILOT SCALE STUDY ON AMMONIUM REMOVAL IN PHAP VAN WATER PLANT, HANOI CITY
Joint Research on Environmental Science and Technology for the Eart
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