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result(s) for
"Frequency variation"
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A random walk-based method to identify driver genes by integrating the subcellular localization and variation frequency into bipartite graph
Background
Cancer as a worldwide problem is driven by genomic alterations. With the advent of high-throughput sequencing technology, a huge amount of genomic data generates at every second which offer many valuable cancer information and meanwhile throw a big challenge to those investigators. As the major characteristic of cancer is heterogeneity and most of alterations are supposed to be useless passenger mutations that make no contribution to the cancer progress. Hence, how to dig out driver genes that have effect on a selective growth advantage in tumor cells from those tremendously and noisily data is still an urgent task.
Results
Considering previous network-based method ignoring some important biological properties of driver genes and the low reliability of gene interactive network, we proposed a random walk method named as Subdyquency that integrates the information of subcellular localization, variation frequency and its interaction with other dysregulated genes to improve the prediction accuracy of driver genes. We applied our model to three different cancers: lung, prostate and breast cancer. The results show our model can not only identify the well-known important driver genes but also prioritize the rare unknown driver genes. Besides, compared with other existing methods, our method can improve the precision, recall and fscore to a higher level for most of cancer types.
Conclusions
The final results imply that driver genes are those prone to have higher variation frequency and impact more dysregulated genes in the common significant compartment.
Availability
The source code can be obtained at
https://github.com/weiba/Subdyquency
.
Journal Article
Study on the Frequency Variation and Amplitude Variation Characteristics of HTS Bulks
High-temperature superconducting (HTS) maglev, with the excellent high-speed operation potential and environmental advantages, is a representative technology of independent innovation in the field of rail transportation. In the practical engineering applications, the maglev is constantly in the state of inevitable vibration. The influence of vibration frequency and amplitude on the levitation characteristics of HTS bulks will undoubtedly affect the vehicle’s dynamic performance. In light of this, this paper investigates the frequency variation characteristics and amplitude variation characteristics of HTS bulks with the method of numerical simulation. Firstly, the dewar model which includes the HTS bulks, insulation boundaries, and liquid nitrogen is established. Secondly, the permanent magnetic guideway (PMG) model is established. Then, combine these two models into a finite element model (FE model) that considers the electromagnetic-thermal coupling. Finally, the frequency and amplitude variation characteristics of HTS bulks are studied by operating different frequencies and amplitudes to dewar. This study provides a detailed analysis of the frequency and amplitude variation characteristics of HTS bulks at medium and low frequencies, providing effective references for the dynamic response of HTS bulks’ levitation characteristics.
Journal Article
Effect of resonant frequency variation on the ultrasonically assisted deep drawing process: numerical and experimental study
This paper focuses on the system frequency variation effect on the ultrasonically assisted deep drawing (UADD) process, based on experimental and numerical approaches. A special ultrasonic die is precisely designed and fabricated to improve draw-ability and reduce the forming force. The longitudinal resonance frequency of the vibratory system is established as 20 kHz prior to forming load application on the system. Consequently, a three-dimensional finite element model of the deformation process is developed. The output of this simulation shows good agreement with the experimental test results. The UADD test with 5 μm amplitude demonstrated 5.6% decrease in maximum average force and 12.2% increase in the drawing ratio when compared with the conventional deep drawing (CDD). In addition, the resonant frequency variation effect on the forming force is revealed during the experimental tests. Since the excitation frequency is tuned out with the natural frequency of the system at the beginning of the test, no forming force reduction was observed at this stage. To further investigate this effect, two complementary steps are implemented in this work. In the first phase, the natural frequency of the system is determined by numerical modal analysis and reshaping the blank at various deformation stages. Consequently, forced vibrations with frequencies very close to the natural frequencies, calculated from the first phase, are applied to the system in the second phase, to simulate the forming process. Based on the validated numerical model, the forming force, friction force, and material flow stress distributions are disclosed for UADD in various excitation frequencies.
Journal Article
Experimental Investigation of Ring-Type Resonator Dynamics
One of the challenges in inertia sensor applications is the need for a class of devices that operate at one of the ring resonant frequencies to achieve large amplitudes of vibration. However, large amplitudes tend to produce undesirable nonlinear effects due to geometrical nonlinearities. Hence, a rigorous experimental dynamic analysis of rotating thin circular ring-type structures is considered important to gain a deeper understanding of the device’s nonlinear behavior as well as the potential performance improvements. This study aims to experimentally investigate the nonlinear dynamic behavior of rotating thin circular rings and the effects of angular rate as well as mass mismatch variations on the system natural frequency. A prototype made of a macroscale thin cylindrical structure is employed to study the nonlinear dynamic behavior of rotating thin circular rings. Using a precision rate table equipped with a slip ring as well as non-contact sensors/actuators, experiments that closely represent the actual physical operating conditions of angular rate sensors are developed. Natural frequency variations due to the input angular rate changes are measured in time and frequency domains. Useful experimental observations on the frequency split and mass mismatch effects have been performed. Typical nonlinear behavior, such as jump phenomena of a rotating thin circular cylinder, is noted. The nonlinear dynamic behavior of a ring-type resonator system, which is subjected to external excitations, is experimentally investigated. Results from the present experimental study on the mechanics of the ring structure are expected to provide further insight into the design and operation of ring-type resonators for angular rate sensing applications.
Journal Article
LPBFuzz: Binary program fuzzing with enhanced coverage of low-frequency program branches
Fuzzing detects hidden defects and vulnerabilities in software by generating a large amount of malformed input data and monitoring program anomalies. The existing fuzzing methods suffer from data imbalance when modeling program branching behaviors, making it difficult to accurately locate data fields that are strongly correlated with low-frequency program branching decisions. In addition, the existing methods do not determine variation direction when mutating the test data and do not distinguish between valid/invalid data fields, resulting in duplicate testing of certain program branches. In this paper, we propose a fuzzing method to enhance the coverage of low-frequency program branches. A low-frequency perception network and a forward gradient-guided mutating strategy are proposed to clarify the magnitude and sign when mutating key data fields. Experiments show that the proposed method effectively improves code coverage by increasing low-frequency branch coverage.
Journal Article
Vibration response analysis on stainless steel thin plate weldments
Dynamic responses of welded thin plates are influenced by welding residual stress, and improving this phenomenon understanding would turn possible to develop a new residual stress detection method. This research investigates natural frequency variations in welded thin plates. Experimental analysis was conducted for eight AISI316LSS plates, 6.30-mm thickness, bead on plate (BOP) and butt welded. Modal variations, comparing natural frequencies before and after welding, are negative, due to longitudinal compressive residual stress predomination. It was detected that higher variations occur for the first torsional mode and the variation for the longitudinal flexural mode is around null. It was observed that BOP welds do not always result in higher modal variations for higher heat inputs, as it occurs with butt welds. Moreover, it shows that, for the same heat inputs, modal variations were higher for butt welds than BOP tests. Numerical analysis was also performed, and theoretical results were compared to experiments.
Journal Article
Tracking Low-Frequency Variations in Land–Sea Water Mass Redistribution during the GRACE/GRACE-FO Era
Climate change has caused a widespread deduction in terrestrial water storage (TWS), leading to ocean water mass gains and sea level rises. A better understanding of how the land–sea water mass has been redistributed can help with the scientific response to climate change. However, there are few studies investigating the roles of the different physical processes involved in low-frequency land–sea water mass redistribution on a global scale. To address this issue, in this study, a comprehensive investigation was carried out with respect to the globally distributed key factors causing low-frequency ocean mass anomalies during the period 2004–2021. Global water mass redistribution data, derived from GRACE/GRACE-FO satellite gravity and surface wind and sea-surface temperature data from ERA5 reanalysis, were employed, and the empirical orthogonal function, maximum covariance analysis, and sea-level equation approaches were used. The results show that the long-term trend and decadal-like fluctuation are two major components of the low-frequency land–sea water mass redistribution. The wind-forcing dynamic processes significantly drive the anomalies near the North Indian Ocean, North Atlantic Ocean, South Pacific Ocean, and some marginal seas, where variance explanations range from 30% to 97%. After removing the ocean dynamics, the residual ocean mass anomaly is mostly explained by sea-level fingerprints (SLFs), especially in the open ocean. The 25th, 50th, and 75th percentiles of the SLF-explained variances in all ocean grids are 59%, 72%, and 82%, respectively. Some non-negligible noise, located in seismic zones, was also found, suggesting the misestimation of seafloor deformation resulting from earthquakes in the GRACE/GRACE-FO data processing. These findings may improve our understanding of the long-term anomalies in regional and global sea levels.
Journal Article
GO/CNT−OH/Nafion Nanocomposite Humidity Sensor Based on the LC Wireless Method
In recent years, LC resonant sensors have gained widespread attention for their extensive applications in industries such as pharmaceutical storage and food transportation. A wireless passive sensor with a good sensing performance is proposed based on a GO/CNT−OH/Nafion nanocomposite. The sensor was fabricated via inkjet printing technology, and the surface morphology of the GO/CNT−OH/Nafion nanocomposite was characterized by SEM measurement. It is found that the MWCNTs support the GO layer and the hydrophobic chains of Nafion interact with the hydrophobic layer of GO, resulting in a larger cavity and hydrophilic surface of the entire material. This structure well reflects the fact that the mixing of MWCNTs and Nafion provides the entire material with a stronger water absorption. The experimental study shows that the proposed humidity sensor has a frequency variation of 103 kHz/%RH at low humidity (30–60% RH) and a sensitivity of 931 kHz/%RH at high humidity (60–95% RH), while the sensitivity value from 30–95% RH is 547 kHz/% RH. The response time and recovery time are 110 s and 115 s, respectively. In addition, the tests showed that the GO/CNT−OH/Nafion nanocomposite applied to the humidity sensor had a maximum humidity hysteresis of about 3% RH at 30–95% RH, the resonant frequency remained basically unchanged after 50 h of testing, and the whole sensor possessed a good stability. After conducting several repeated experiments, it was found that the resonant frequency error of the whole sensor was low and did not affect the overall sensing test, which proved the reproducible preparation of the sensor. Finally, the humidity-sensing mechanism of the proposed sensor was analyzed in this paper, and it was found that GO enhanced the hygroscopic properties of GO/CNT−OH/Nafion nanocomposite when it was supported by MWCNT-OH and included uniformly dispersed Nafion. Therefore, our proposed humidity sensor is suitable for humidity detection above 30% RH in both sealed and open environments.
Journal Article
Damage Estimation of Full-Scale Infilled RC Frames under Pseudo-Dynamic Excitation by Means of Output-Only Modal Identification
To assess the health condition of structures and infrastructure during their service lives, continuous vibration-based monitoring represents a viable and cost-effective solution. Model updating and digital twins are increasingly adopted for damage detection. However, significant gaps and uncertainties in damage quantification still arise. This work presents original data from output-only modal identification tests on full-scale, two-storey reinforced concrete (RC) frames subjected to pseudo-dynamic loading to simulate seismic damage. The frames are tested with two masonry infill wall configurations with three-sided and four-sided boundary conditions, and the observed seismic damage is correlated to a damage scale. Output-only modal identification tests are performed before and after testing to catch variations in modal properties due to observed damage. Experimental data are used to build a refined finite element model able to reliably simulate the static and dynamic performance of the infilled RC frames before and after damage. The model allowed for the further assessment of the variation in natural frequencies of tested specimens at different earthquake intensities, the correlation of such variations to damage levels, and identification of the contribution of structural and non-structural components to the overall frequency variation.
Journal Article