sensitive region
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2021 ◽  
Vol 932 ◽  
Author(s):  
Jichao Li ◽  
Mengqi Zhang

This work studies the application of a reinforcement learning (RL)-based flow control strategy to the flow past a cylinder confined between two walls to suppress vortex shedding. The control action is blowing and suction of two synthetic jets on the cylinder. The theme of this study is to investigate how to use and embed physical information of the flow in the RL-based control. First, global linear stability and sensitivity analyses based on the time-mean flow and the steady flow (which is a solution to the Navier–Stokes equations) are conducted in a range of blockage ratios and Reynolds numbers. It is found that the most sensitive region in the wake extends itself when either parameter increases in the parameter range we investigated here. Then, we use these physical results to help design RL-based control policies. We find that the controlled wake converges to the unstable steady base flow, where the vortex shedding can be successfully suppressed. A persistent oscillating control seems necessary to maintain this unstable state. The RL algorithm is able to outperform a gradient-based optimisation method (optimised in a certain period of time) in the long run. Furthermore, when the flow stability information is embedded in the reward function to penalise the instability, the controlled flow may become more stable. Finally, according to the sensitivity analyses, the control is most efficient when the probes are placed in the most sensitive region. The control can be successful even when few probes are properly placed in this manner.


Author(s):  
Peng Huang ◽  
Jianyu Fu ◽  
Yihong Lu ◽  
Jinbiao Liu ◽  
Jian Zhang ◽  
...  

Abstract Thermopile sensors have a wide range of applications in consumer and industry. Seebeck coefficient is a basic thermal parameter of thermopile sensors. Extracting the Seebeck coefficient of both materials and thermocouple in thermopile sensors is of great importance. In this work, an on-chip test structure is designed. It consists of a substrate, a framework, supporting legs and a sensitive region which has a resistor serving as both heater and temperature detector. A set of on-chip test structures are fabricated along with a thermopile sensor. Its measurement results are analyzed and compared with apparatus measurement results. These results are consistent with each other, and the validity of structure is verified.


2021 ◽  
Vol 7 (45) ◽  
Author(s):  
Toby Candler ◽  
Noah Kessler ◽  
Chathura Gunasekara ◽  
Kate Ward ◽  
Philip James ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Imran Memon ◽  
Riaz Ahmed Shaikh ◽  
Mohammad Kamrul Hasan ◽  
Rosilah Hassan ◽  
Amin Ul Haq ◽  
...  

The Internet of Things (IoT) is susceptible to several identities, primarily based on attacks. However, these attacks are controlling for IoT due to extraordinary growth in consumers’ density and slight analysis with low power access nodes. In this work, we explore the possible flaws associated with security for IoT environment insensitively meant for transfer conditions. We proposed a novel design aimed at detecting a spoofing attack that inspects the probability distributions of received power founded for the regions designed for mobile (moving) users. Additionally, we examine the influence on the Confidentiality Scope of targeted consumers in the absence and presence of observer. Our approaches were done through simulation results used for three diverse regions. Grounded on outcomes, we suggest an algorithm called MTFLA, which will guarantee detection and protection techniques intended to protect vastly sensitive areas, i.e., wherever the chance of an attack is maximized. We provide a comparison among various security algorithms prepared for the energy consumption of different patterns. Simulation results revealed that the proposed algorithm for protection (MTFL) is verified to be energy-proficient (secure garnering). It decreases the energy prerequisite for encrypting the data. We evaluated our techniques over simulation results for sensitive region information built on fuzzy logic.


2020 ◽  
Vol 77 (10) ◽  
pp. 3387-3405
Author(s):  
Chih-Chi Hu ◽  
Chun-Chieh Wu

AbstractEnsemble sensitivity analysis based on convective-permitting ensemble simulations is used to understand the processes associated with tropical cyclone (TC) intensification under idealized conditions. Partial correlations between different variables and the future TC intensification rate, with the effect of intensity removed, are used to identify the sensitive factors. It is found that the equivalent potential temperature (θe) in the region from the radius of maximum wind (RMW) to 3 times the RMW below 2 km (hereafter, the sensitive region) has the largest correlation (over 0.7) with 2.5-h intensity change. It is found that higher θe in the sensitive region is associated with not only a stronger updraft but also an inward shift of vertical motion in the mid- to upper eyewall. This suggests that higher θe just outside the RMW is favorable to TC intensification not only because of the larger amount of the heating, but also due to the heating location that is closer to the center. Trajectory analysis shows that the parcels in the sensitive region are mainly from the boundary layer inflow and the midlevel inflow. It is found that when the outer rainband is active, the midlevel inflow becomes stronger and is able to bring more low-θe air into the boundary layer, and the θe radially inward to the rainband decreases. Verification experiments justify that higher θe around the RMW to 3 times the RMW is favorable to TC intensification, while higher θe away from 5 times the RMW is shown to be unfavorable for TC intensification.


2020 ◽  
Vol 189 (3) ◽  
pp. 286-293
Author(s):  
Arghya Chattaraj ◽  
T Palani Selvam

Abstract Applicability of pure propane gas for microdosimetric measurements at photon energies relevant in brachytherapy is studied using the Monte Carlo-based FLUKA code. Monoenergetic photons in the energy range of 20–1250 keV and brachytherapy sources such as 103Pd, 125I, 169Yb, 192Ir, 137Cs and 60Co are considered in the study. Using the calculated values of energy deposited in the sensitive region of LET-1/2 tissue-equivalent proportional counter filled with pure propane gas and tissue-equivalent propane gas, values of density scaling factor for the site sizes of 1 and 8 μm are obtained. The study shows that density of propane gas should be lowered by a factor of about 0.93 for 169Yb, 192Ir, 137Cs and 60Co sources for the site sizes of 1–8 μm. For 125I source, the density of propane gas requires a scaling of 0.93 for 1 μm site size, whereas for site sizes 2–8 μm, density need not be altered. 103Pd source does not require density scaling for site sizes 1–8 μm.


10.29007/58s9 ◽  
2020 ◽  
Author(s):  
Thitivatr Patanasakpinyo ◽  
Les Miller

An adaptive software system is known as an application that can adapt itself based on different conditions of users. There are multiple conditions/criteria that can be used to direct how an application would adapt. Spatial visualization (VZ) is one of several human spatial abilities that is used to predict human’s performance when using a computer application. Therefore, a difference in VZ level is a suitable choice as an adapting indicator, i.e., high VZ and low VZ users should get different features on a user interface (UI) to complete the same task. In this paper, we look at three studies where we asked participants to verify a set of housing addresses using a location-based application on an Android tablet with different versions of the application, especially, an adaptive version of the application was involved in the last study. We found that, for high VZ participants, the number of UI errors that participants created was significantly smaller when they were equipped with the adaptive software. We refer to a UI error (User Interface Error) as an error where a user tapped on a non-sensitive region of the screen. The results of the three studies and hypothesis tests for significance are reported.


2019 ◽  
Vol 30 (8) ◽  
pp. 4067-4081
Author(s):  
Xu Han ◽  
Xiangyu Liu ◽  
Yunyun Yuan ◽  
Zhonghe Han

Purpose The flow state of wet steam will affect the thermodynamic and aerodynamic characteristics of steam turbine. The purpose of this study is to effectively control the wetness losses caused by wet steam condensation, and hence a cascade of 600 MW steam turbine was taken as the research object. Design/methodology/approach The influence of blade surface roughness on the condensation characteristics was analyzed, and the dehumidification mechanism and wetness control effect were obtained. Findings With the increase of blade surface roughness, the peak nucleation rate decreases gradually. According to the Mach number distribution on the blade surface, there is a sensitive region for the influence of roughness on the aerodynamic performance of cascade. The sensitive region of nucleation rate roughness should be between 50 and 150 µm. Originality/value The increase of blade surface roughness will increase the dynamic loss in cascade, but it can reduce the thermodynamic loss caused by condensation to a certain extent.


2019 ◽  
Vol 48 (6) ◽  
pp. 415-421
Author(s):  
M. E. Chernyak ◽  
E. V. Ranneva ◽  
A. V. Ulanova ◽  
A. Yu. Nikiforov ◽  
A. I. Verizhnikov ◽  
...  
Keyword(s):  
X Ray ◽  

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