133 research outputs found
Properties of Generalized Forchheimer Flows in Porous Media
The nonlinear Forchheimer equations are used to describe the dynamics of
fluid flows in porous media when Darcy's law is not applicable. In this
article, we consider the generalized Forchheimer flows for slightly
compressible fluids and study the initial boundary value problem for the
resulting degenerate parabolic equation for pressure with the time-dependent
flux boundary condition. We estimate -norm for pressure and its time
derivative, as well as other Lebesgue norms for its gradient and second spatial
derivatives. The asymptotic estimates as time tends to infinity are emphasized.
We then show that the solution (in interior -norms) and its gradient
(in interior -norms) depend continuously on the initial and
boundary data, and coefficients of the Forchheimer polynomials. These are
proved for both finite time intervals and time infinity. The De Giorgi and
Ladyzhenskaya-Uraltseva iteration techniques are combined with uniform
Gronwall-type estimates, specific monotonicity properties, suitable parabolic
Sobolev embeddings and a new fast geometric convergence result.Comment: 63 page
CRLH Leaky-Wave Antenna with High Gain and Wide Beam-Scanning Angle for 5G mmWave Applications
In this paper, a novel composite right-/left-handed (CRLH) leaky-wave antenna with a simple structure, low cost, high gain, and wide beam-scanning range performance for the millimeter wave (mmWave) band. The proposed antenna comprises a series-fed array of asymmetrically slotted elliptical CRLH unit cells loaded with a short-circuit stub. By optimizing the length of the stub, the condition of the CRLH structure is balanced to enable beam scanning from the backward to the forward direction within the mmWave band. The proposed antenna exhibits a wide beam-scanning angle of 112° (−60° to 52°), coupled with high gain and radiation efficiency at the designated band. Furthermore, it is fabricated on a traditional microwave substrate, Rogers RT/duroid 5880, thus offering a cost-effective approach to streamlining the manufacturing process. The measurement results confirmed a peak realized gain of 16.8 dBi. The excellent performance achieved using a low-cost design makes the proposed antenna attractive for 5G mmWave applications
A Deep Learning-Based Aesthetic Surgery Recommendation System
We propose in this chapter a deep learning-based recommendation system for aesthetic surgery, composing of a mobile application and a deep learning model. The deep learning model built based on the dataset of before- and after-surgery facial images can estimate the probability of the perfection of some parts of a face. In this study, we focus on the most two popular treatments: rejuvenation treatment and eye double-fold surgery. It is assumed that the outcomes of our history surgeries are perfect. Firstly a convolutional autoencoder is trained by eye images before and after surgery captured from various angles. The trained encoder is utilized to extract learned generic eye features. Secondly, the encoder is further trained by pairs of image samples, captured before and after surgery, to predict the probability of perfection, so-called perfection score. Based on this score, the system would suggest whether some sorts of specific aesthetic surgeries should be performed. We preliminarily achieve 88.9 and 93.1% accuracy on rejuvenation treatment and eye double-fold surgery, respectively
LAND USE CHANGE AND RELATED PROBLEMS UNDER URBANIZATION IN SUBURBAN AREA OF HANOI CITY (A CASE STUDY OF HOANG LIET COMMUNE, THANH TRI DISTRICT)
Joint Research on Environmental Science and Technology for the Eart
TSRNet: Simple Framework for Real-time ECG Anomaly Detection with Multimodal Time and Spectrogram Restoration Network
The electrocardiogram (ECG) is a valuable signal used to assess various
aspects of heart health, such as heart rate and rhythm. It plays a crucial role
in identifying cardiac conditions and detecting anomalies in ECG data. However,
distinguishing between normal and abnormal ECG signals can be a challenging
task. In this paper, we propose an approach that leverages anomaly detection to
identify unhealthy conditions using solely normal ECG data for training.
Furthermore, to enhance the information available and build a robust system, we
suggest considering both the time series and time-frequency domain aspects of
the ECG signal. As a result, we introduce a specialized network called the
Multimodal Time and Spectrogram Restoration Network (TSRNet) designed
specifically for detecting anomalies in ECG signals. TSRNet falls into the
category of restoration-based anomaly detection and draws inspiration from both
the time series and spectrogram domains. By extracting representations from
both domains, TSRNet effectively captures the comprehensive characteristics of
the ECG signal. This approach enables the network to learn robust
representations with superior discrimination abilities, allowing it to
distinguish between normal and abnormal ECG patterns more effectively.
Furthermore, we introduce a novel inference method, termed Peak-based Error,
that specifically focuses on ECG peaks, a critical component in detecting
abnormalities. The experimental result on the large-scale dataset PTB-XL has
demonstrated the effectiveness of our approach in ECG anomaly detection, while
also prioritizing efficiency by minimizing the number of trainable parameters.
Our code is available at https://github.com/UARK-AICV/TSRNet.Comment: Accepted at ISBI 202
Zone-based Federated Learning for Mobile Sensing Data
Mobile apps, such as mHealth and wellness applications, can benefit from deep
learning (DL) models trained with mobile sensing data collected by smart phones
or wearable devices. However, currently there is no mobile sensing DL system
that simultaneously achieves good model accuracy while adapting to user
mobility behavior, scales well as the number of users increases, and protects
user data privacy. We propose Zone-based Federated Learning (ZoneFL) to address
these requirements. ZoneFL divides the physical space into geographical zones
mapped to a mobile-edge-cloud system architecture for good model accuracy and
scalability. Each zone has a federated training model, called a zone model,
which adapts well to data and behaviors of users in that zone. Benefiting from
the FL design, the user data privacy is protected during the ZoneFL training.
We propose two novel zone-based federated training algorithms to optimize zone
models to user mobility behavior: Zone Merge and Split (ZMS) and Zone Gradient
Diffusion (ZGD). ZMS optimizes zone models by adapting the zone geographical
partitions through merging of neighboring zones or splitting of large zones
into smaller ones. Different from ZMS, ZGD maintains fixed zones and optimizes
a zone model by incorporating the gradients derived from neighboring zones'
data. ZGD uses a self-attention mechanism to dynamically control the impact of
one zone on its neighbors. Extensive analysis and experimental results
demonstrate that ZoneFL significantly outperforms traditional FL in two models
for heart rate prediction and human activity recognition. In addition, we
developed a ZoneFL system using Android phones and AWS cloud. The system was
used in a heart rate prediction field study with 63 users for 4 months, and we
demonstrated the feasibility of ZoneFL in real-life
A Survey on Some Parameters of Beef and Buffalo Meat Quality
A survey was carried out on 13 Vietnamese Yellow cattle, 14 LaiSind cattle and 18 buffalos in
Hanoi to estimate the quality of longissimus dorsi in terms of pH, color, drip loss, cooking loss and tenderness at 6 different postmortem intervals. It was found that the pH value of longissimus dorsi was not significantly different among the 3 breeds (P>0.05), being reduced rapidly during the first 36 hours postmortem, and then stayed stable. The value was in the range that was considered to be normal. Conversely, the color values L*, a* and b* tended to increase and also stable at 36 hours postmortem, except that for LaiSind cattle at 48 hours. According to L* scale, the meat of Yellow and LaiSind cattle met the normal quality but the buffalo meat was considered to be dark cutters. The tenderness of longissimus dorsi was significantly different among the breeds (P<0.05). The value was highest at 48 hours and then decreased for LaiSind and buffalo, but for Yellow cattle the value decreased continuously after slaughtering In terms of tenderness buffalo meat and Yellow cattle meat were classified as “intermediate”, while LaiSind meat was out of this interval and classified as “tough”. Drip loss ratio was increased with the time of preservation (P<0.05). The cooking loss ratio was lowest at 12 hours and higher at the next period, but there was no significant difference among the periods after 36 hours postmotem.Peer reviewe
Lower and upper bound intercept probability analysis in amplifier-and-forward time switching relaying half-duplex with impact the eavesdropper
In this paper, we proposed and investigated the amplifier-and-forward (AF) time switching relaying half-duplex with impact the eavesdropper. In this system model, the source (S) and the destination (D) communicate with each other via a helping of the relay (R) in the presence of the eavesdropper (E). The R harvests energy from the S and uses this energy for information transferring to the D. For deriving the system performance, the lower and upper bound system intercept probability (IP) is proposed and demonstrated. Furthermore, the Monte Carlo simulation is provided to justify the correctness of the mathematical, analytical expression of the lower and upper bound IP. The results show that the analytical and the simulation curves are the same in connection with the primary system parameters
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