Interference Model Research Articles

Mathematical and Numerical Modelling of Interference of Immune Cells in the Tumour Environment

In this article, the behaviour of tumour growth and its interaction with the immune system have been studied using a mathematical model in the form of partial differential equations. However, the development of tumours and how they interact with the immune system make up an extremely complex and little-understood system. A new mathematical model has been proposed to gain insight into the role of immune response in the tumour microenvironment when no treatment is applied. The resulting model is a set of partial differential equations made up of four variables: the population density of tumour cells, two different types of immune cells (CD4+ helper T cells and CD8+ cytotoxic T cells), and nutrition content. Such kinds of systems also occur frequently in science and engineering. The interaction of tumour and immune cells is exemplified by predator-prey models in ecology, in which tumour cells act as prey and immune cells act as predators. The tumour-immune cell interaction is expressed via Holling’s Type-III and Beddington-DeAngelis functional responses. The combination of finite volume and finite element method is used to approximate the system numerically because these approximations are more suitable for time-dependent systems having diffusion. Finally, numerical simulations show that the methods perform well and depict the behaviour of the model.

A Modification to the Enhanced Correction Factor Technique for the Subsonic Wing–Body Interference Model

In this work, the enhanced correction factor technique (ECFT) is modified for a subsonic wing–body interference model, which can consider the forces on both the lifting boxes and the body elements of an idealized airplane, termed the advanced ECFT method. A passenger aircraft model is chosen as the simulation model, and the longitudinal static aeroelasticity at the transonic situation for two-degree freedom, including the α (angle of attack) degree and ϕ (angle of horizontal tail) degree, is simulated in this paper. The corresponding CFD results are used to correct the aerodynamic influence coefficients (AIC) matrix, which is then simulated by MSC.NASTRAN. The pressure distribution results of different aircraft components received by the advanced ECFT method indicate that it is suitable for the subsonic wing–body interference model. Compared with the uncorrected linear method and the diagonal corrected method, it is generally more consistent with the CFD/CSD coupling method, not only for the lifting boxes, but also for the body elements. In addition, the aerodynamic derivative results also show good agreement with the flight test data, which solidly verifies the advance ECFT method.

An Online Evolutionary Aeromagnetic Compensation Method Using Woodbury Equation

Aeromagnetic compensation is important in aeromagnetic detection. Traditionally, a calibration flight would be implemented to estimate the interference model. However, the magnetic interference is not constant during the mission flight, which makes the interference model constructed in the calibration flight inapplicable in the mission. To solve that problem, this paper proposes an evolutionary aeromagnetic compensation method based on Woodbury equation. With this method, the magnetic interference model parameters can be evolved during the mission flight on basis of the previous interference model and the updated acquired data. To evaluate the performance of the evolutionary method, both simulation and the experiment were conducted. The results indicate that the proposed method can effectively reduce the influence of changing magnetic interference. In the experiment, the standard deviation (STD) of measured data before compensation in the last mission flight is 1.2070nT, the traditional compensation can reduce the STD to 0.0863nT, while our evolutionary aeromagnetic compensation method can reduce STD to 0.0450nT. The results show that increasing changes of magnetic interference will make evolutionary aeromagnetic compensation vital for isolating signals created by geologic features from signals created by the aircraft.

Optimal non‐circular designs for total effects under interference models

In block designs, the responses of plots are potentially influenced by the treatments of neighbouring plots and the surrounding environment. Many researchers use two guarding plots next to the edge plots, for which we apply certain treatments to control these environmental effects. Thus, a design is presented as a collection of treatment sequences. For the estimation of total effects, existing results consider circular designs, whose constraints are unnecessary in common applications. In this paper, we construct optimal or highly efficient non‐circular designs under interference models. It is observed that the optimal non‐circular designs for the total effects outperform the optimal circular designs in many instances. In fact, a design containing a circular sequence cannot be optimal for .

Meiotic crossover interference: Methods of analysis and mechanisms of action.

Segregation of chromosomes during meiosis, to form haploid gametes from diploid precursor cells, requires in most species formation of crossovers physically connecting homologous chromosomes. Along with sister chromatid cohesion, crossovers allow tension to be generated when chromosomes begin to segregate; tension signals that chromosome movement is proceeding properly. But crossovers too close to each other might result in less sister chromatid cohesion and tension and thus failed meiosis. Interference describes the non-random distribution of crossovers, which occur farther apart than expected from independence. We discuss both genetic and cytological methods of assaying crossover interference and models for interference, whose molecular mechanism remains to be elucidated. We note marked differences among species.

Algorithm-Based Optimal and Efficient Exact Experimental Designs for Crossover and Interference Models

The crossover models and interference models are frequently used in clinical trials, agriculture studies, social studies, etc. While some theoretical optimality results are available, it is still challenging to apply these results in practice. The available theoretical results, due to the complexity of exact optimal designs, typically require some specific combinations of the number of treatments (t), periods (p), and subjects (n). A more flexible method is to build integer programming based on theories in approximate design theory, which can handle general cases of $(t,p,n)$. Nonetheless, those results are generally derived for specific models or design problems and new efforts are needed for new problems. These obstacles make the application of the theoretical results rather difficult. Here we propose a new algorithm, a revision of the optimal weight exchange algorithm by [1]. It provides efficient crossover designs quickly under various situations, for different optimality criteria, different parameters of interest, different configurations of $(t,p,n)$, as well as arbitrary dropout scenarios. To facilitate the usage of our algorithm, the corresponding R package and an R Shiny app as a more user-friendly interface has been developed.

A new calculation method of bearing reliability of tyre unloader based on heterogeneous dimensional interference model

Bearing is an important rotating support part of tyre unloader, and its fatigue reliability is an important part of the whole system reliability. Because of the huge alternating stress, the support bearing is required to have high fatigue life and reliability. In this paper, combined with stress-strength interference model and statistical theory, the life distribution of bearing steel material is predicted by using group test data; Based on the multi-rigid body dynamics and finite element numerical simulation platform, the reliability of the bearing of tyre unloader under different operating years was predicted by using the different dimensional interference model. The results show that the maximum resultant force of the bearing at the bottom rocker arm of the tyre unloader can reach 150kN, and the maximum transverse and longitudinal forces can reach 108kN and 78kN. When bearing the weight of the whole tyre and turning, the inertia force is the largest, the maximum stress value is 1316.2MPa, which occurs in the bearing inner ring and ball contact part. After the statistics, the stress amplitude distribution of the bearing conforms to Weibull distribution, and the life of the bearing follows lognormal distribution. After 105 tyre unloading, the fatigue reliability of the bearing is lower than 0.82, which is consistent with the actual working condition. Therefore, this model can be used to calculate the fatigue reliability of bearings conveniently and quickly, and provide certain theoretical support for the safety and fatigue reliability prediction of bearings.

Strategy or local control? Interaction of Gratton effect and proportion’s effect in the Stroop test

Models of cognitive control contain the mechanism of the general strategy of solving a task and control of specific stimuli special mechanisms. There is an ongoing discussion as to which control is responsible for the Gratton effect and the Stroop test’s proportion effect. The Gratton effect consists in decreasing the Stroop effect after an incongruent stimulus, the proportion effect is to increase interference when incongruent stimuli predominate among other types of stimuli. In this study, we set out to test whether there would be an interaction between these effects. If it is detected, we can say that both effects of study are produced by a general cognitive mechanism. Similar studies of general strategy using the Stroop task include congruent and incongruent stimuli. Congruent stimuli produce a response facilitation effect that is mixed with an interference effect, making final interpretation difficult. To avoid this, we used different proportions of incongruent and neutral stimuli. We conducted three experiments using different proportions of incongruent versus neutral stimuli (66:33/33:66 and 80:20/20:80), as well as the type of design (intragroup and intergroup plans). Only the Gratton effect was detected in the experiments performed — no proportion effect or significant interaction between the Gratton and proportion effects was found. In three experiments (N=70), only indirect evidence was found for the effect of proportion on the Gratton effect. These results are difficult to explain in terms of “strategic” interference model who explain both effects by a change in the global strategy for solving the task. Given the systematic lack of interaction between the Gratton effect and other effects in the literature, we can say that the Gratton effect is caused by a local control system, which the proportion effect influences, if at all, only slightly. The connection between the proportion effect and strategic control and the factors that mediate it are discussed.

Modeling and Mitigation of Radio Frequency Interference for Wireless Devices

This article reviews the electromagnetic framework used to model radio frequency interference (RFI) and the resulting development of mitigation methods. With the rise of IoT devices, wireless devices in which RF antennas are integrated with high-performance digital systems in small form factors suffer from electromagnetic interference, known as RF interference or RF desensitization. The simple yet rigorous framework can be used for a systematic RFI-aware design, saving time and effort for trial-and-error troubleshooting.

Разработка моделей скрытного воздействия на инфраструктуру беспроводных сетей с помощью сигналоподобных помех и оценка их устойчивости к обнаружению

Introduction: The article discusses scenarios in which, according to the 802.11 standard, deauthentication frames should be sent from a user or access point. The developed hardware and software complex records such interaction and then broadcasts it as interference. The object of research is IEEE 802.11 wireless networks, the development of models for the covert effect of signal-like interference using USRP on the physical data transmission medium. The subject of the study is the development of signs of detection of DoS effects by these models of signallike interference. The hardware basis is the equipment of National Instruments USRP NI 2901, and the software basis is NI LabVIEW 2018, with which the configuration and management of USRP equipment takes place. The results of the study can be applied when setting up automatic network administration systems (IDS/IPS systems), which will allow timely detection of the impact, increasing the security of wireless communication networks.

Analysis of the Speed Limit of Transrapid Maglev Train Explored From the Perspective of Its Suspension and Guidance Systems

In recent years, research on high-speed or ultra-high-speed maglev systems has become increasingly popular, and different countries or teams have been committing to several different suspension technologies. Among them, due to the profound accumulation of research on the normal-conducting electromagnetic suspension technology, China is actively adopting this suspension technology to develop a new high-speed maglev train faster than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$600~km/h$ </tex-math></inline-formula> , and this work is mainly on the basis of Transrapid (TR) trains and Shanghai Maglev Line (SHML). To evaluate the feasibility of this project, the speed limit of the TR maglev system was explored from the perspective of its suspension and guidance systems. The analysis process was carried out from two aspects of aerodynamic interference and track irregularity. As for aerodynamic interference, the aerodynamic and electromagnetic simulation models were established based on the actual maglev train. The anti-interference abilities of the suspension and guidance systems were analyzed from two aspects of steady-state and transient-state respectively. The results verified that the train could operate safely when its speed below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$800~km/h$ </tex-math></inline-formula> and the cross-wind speed below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$26~m/s$ </tex-math></inline-formula> . As for track irregularity, based on the actual track construction indicators of the SHML, the relationship between suspension gap fluctuation and the train speed was studied through a dynamic calculation model of the suspension control system. The results showed that the suspension system had a risk of track collision when the train speed was greater than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$717~km/h$ </tex-math></inline-formula> . In summary, from the perspective of its suspension and guidance systems, the current TR maglev system on the SHML has an upper speed limit. The conclusion would be valuable for the development of ultra-high-speed maglev systems in the future.

Study on The Technology of Optical Fiber High-Temperature Pressure Sensor with Weak Temperature Sensitivity

In aerospace, petrochemical, gas turbines and other high-temperature environments, pressure measurement of equipment has always been a challenge to be solved. The electrical high temperature pressure sensor has the problem of component failure in the high temperature environment, and it is difficult to use in the high temperature environment for a long time. The detection device of the optical fiber sensor does not include electrical components, so it has the advantages of high working temperature, high measurement accuracy, anti-electromagnetic interference and so on. In order to measure pressure in high temperature environment with sensor, a temperature-weakly sensitive optical fiber Micro-Electro-Mechanical System (MEMS) pressure sensing technology is proposed. The technique uses Extrisic Fabry-Perot Interference (EFPI) model. It uses the MEMS pressure chip to passively modulate the optical signal of the interference, and then realizes the pressure signal measurement. Among them, MEMS pressure sensitive chip is the core component of the sensor. The MEMS pressure sensitive chip adopts the design method of all solid state vacuum absolute pressure. Changes in environmental pressure will deform the membrane. This phenomenon can cause changes in the cavity of the EFPI cavity. Therefore, stress information can be obtained by measuring changes in EFPI cavity. The thermal stress and temperature parasitical response introduced by thermal expansion of the material are calculated by simulation. The influence of temperature signal on chip displacement is analyzed by the above results. On this basis, combined with the sub-micron white light interference response technology and low thermal stress packaging technology, the high temperature pressure sensor prototype is developed. In order to test the actual measurement ability of the sensor, this paper does the pressure test and high temperature test respectively. When the pressure changes from 0kpa to 100kpa, the spectral intensity of the sensor output has a linear relationship with the pressure. During the temperature change from 20℃ to 400℃, the spectral intensity of the sensor output did not change significantly. The experimental test results show that the pressure measurement of 0~100kPa can be satisfied in the range of 20~400℃, and the measurement error introduced by temperature change is less than 4%. Therefore, the fiber pressure sensor can be used to measure pressure in high temperature environment.

Optimal non‐circular designs for interference models

In many applications of block designs, the responses of plots are affected by treatments in neighbouring plots. What makes it more complicated is the border effect on the two edge plots caused by potential environmental impacts outside the blocks. For the latter, many researchers use two guarding plots next to the edge plots, for which we apply certain treatments to control these impacts. There have been extensive studies of designs under this set‐up; however, we observe that existing literature has been focusing on circular designs where the treatments applied to the border effects are the same as the edge plots on their opposite sides. This structural restriction is unnecessary in most applications. We consider non‐circular designs, where guarding plots are allowed to take any treatments by design. In this paper, optimal non‐circular designs are constructed for direct effects estimations. It is found that optimal non‐circular designs outperform optimal circular designs in many cases, especially for many commonly studied cases in the literature.

Performance Analysis of Beacon-Assisted Wireless Powered Communications With Spatially Random Sensors

In this work, we present the performance evaluation of a power beacon-assisted wireless-powered communication system in the presence of multiple co-channel interferers. We consider and compare three distinct interference modeling scenarios, namely the totally induced interference is approximated by the Gamma distribution, interferers are distributed according to a Poisson point process and interferers are distributed according to a binomial point process. Analytical expressions for the outage probability and the ergodic capacity of the considered system under each interference scenario are derived. Furthermore, optimization problems are formulated to determine the optimum switching time maximizing the achieved ergodic capacity. Numerical results accompanied with Monte Carlo simulations are presented to corroborate the proposed theoretical analysis.

Evolution of extreme events in chaotic light-injected semiconductor lasers

&lt;sec&gt;Rare ultrahigh pulses, classified as rogue waves (RWs), are inevitable and catastrophic in many different systems. Considering the damage they may produce, it is meaningful to understand the formation mechanism of these pulses and, if possible, control them. However, the rarity of RW and the difficulty in implementing the experiment are major limitations to understanding their formation. In 2007, Solli et al. (Solli D R, Ropers C, Koonath P, Jalali B &lt;ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.nature.com/articles/nature06402"&gt;2007 &lt;i&gt;Nature&lt;/i&gt; &lt;b&gt;450&lt;/b&gt; 1054&lt;/ext-link&gt;) introduced the concept of optical RW, i.e. extreme event (EE) by comparing the appearance of oceanic RWs with the propagation of light fields in optical fibers. After that, the research of EEs entered into a flourishing period and different optical systems were proposed to analyze the generation and origin of EEs. Linear system is one of the most widely studied EE systems, such as linear light propagation in glass fibers, random media, and linear interference models. In addition to the linear systems mentioned above, efforts have also been made to produce nonlinear systems of EEs, such as microstructure fibers and tapered gradient exponential nonlinear fibers. In these nonlinear systems, the formation mechanism of EE is studied by using the nonlinear Schrödinger equation. Recently, the EEs in semiconductor laser systems have received a great deal of attention. On the one hand, semiconductor lasers with rich dynamic properties provide a cheap and controllable platform for understanding and predicting EE. The behavior of EE, on the other hand, is a powerful tool for understanding the fundamental mechanism of different laser systems.&lt;/sec&gt;&lt;sec&gt;In this work, based on the EEs generated in a semiconductor laser with phase-conjugate optical feedback (the master laser, ML), we inject its output into another free-running semiconductor laser (the slave laser, SL) and discuss the evolution of EEs in the system by numerical simulation. Herein, we analyze the influence of injection parameters on EEs through the two-dimensional maps of the relative number of EEs in the injection-parameter space. It can be concluded that in an area of high correlation, the relative number of EEs in SL tends to be a stationary value close to that in ML, while it may be enhanced in some weakly correlated regions. The results demonstrate the possibility of controlling EEs by optical injection, which is beneficial to optimizing the performance of chaotic laser systems or expanding their application scope.&lt;/sec&gt;

Interval Uncertainty-Oriented Optimal Control Method for Spacecraft Attitude Control

Research on uncertainty-oriented optimal attitude control of spacecraft with complex space environments and multi-source uncertainties is a research hotspot. Considering that the uncertain parameters in the control system are difficult to quantify, this study proposed an interval uncertainty-oriented optimal control method based on the linear quadratic regulator (LQR) for spacecraft attitude control. The interval state-space equation of the spacecraft attitude dynamic with uncertain controlled feedback gain was constituted by expanding the deterministic model into an order-extended interval matrix format. Based on the interval uncertainty propagation method, the interval-based Riccati equation in LQR was proposed using the modified interval estimation method. Therefore, the interval-controlled feedback gain and interval cost function could be obtained, and the overestimation attributed to the interval expansion could be avoided. The interval-based reliability was investigated using the state-threshold interference model, and the interval-based safety index was developed. The interval uncertainty-based multi-objective optimal control model with constraints was proposed to balance both minimizations of the optimal control cost function and state vector fluctuation by considering these two interval indices as the constraints in optimal control. A flowchart and a numerical example of satellite attitude control were applied to reflect the effectiveness.

Terahertz Chiral Metasurface for Dual-Band Spin-Selective Absorption With Strong Circular Dichroism

The spin-selective absorption (SSA) usually means absorbing one spin state of a circular polarized (CP) wave while reflecting the orthogonal one. Here, we propose two types (type 1 and type 2) of dual-band SSA with strong circular dichroism based on chiral metasurface operating at the terahertz region. For the proposed dual-band SSA metasurface, type 1 can absorb the same spin state of a CP wave in two adjacent bands, while type 2 can absorb one spin state of a CP wave in the first band and absorb the orthogonal one in the second band. The physical mechanism of the proposed SSA metasurface is discussed by introducing the multiple interference model with a detailed equation derivation process. The theoretically calculated results are well-consistent with the simulated one. Four samples (including two types of dual-band SSA metasurface and their mirrored structure) were fabricated and measured to demonstrate our strategy. Finally, the THz near-field imaging is implemented based on the proposed dual-band SSA metasurface to demonstrate their potential applications in multiband THz CP wave detection and image encryption.

Dynamic Reliability Evaluation and Life Prediction of Transmission System of Multi-Performance Degraded Wind Turbine

Wind power is a kind of important green energy. Thus, wind turbines have been widely utilized around the world. Wind turbines are composed of many important components. Among these components, the failure rate of the transmission system is relatively high in wind turbines. It is because the components are subjected to aerodynamic loads for a long time. In addition, its inertial load will result in fatigue fracture, wear and other problems. In this situation, wind turbines have to be repaired at a higher cost. Moreover, the traditional reliability methods are difficult to deal with the above challenges when performing the reliability analysis of the transmission system of wind turbines. To solve this problem, a stress-strength interference model based on performance degradation is introduced. Based on considering the strength degradation of each component, the improved Monte Carlo method simulation based on the Back Propagation neural network is used to obtain the curve of system reliability over time. Finally, the Miner linear cumulative damage theory and the Carten-Dolan cumulative damage theory method are used to calculate the cumulative damage and fatigue life of the gear transmission system.

IMT to Satellite Stochastic Interference Modeling and Coexistence Analysis of Upper 6 GHz-Band Service

IMT to Satellite Stochastic Interference Modeling and Coexistence Analysis of Upper 6 GHz-Band Service

Methodology and Performance Assessment of Three-Dimensional Vehicular Ad-Hoc Network Simulation

Packet-based simulation is a key tool for the research and development of Vehicular Ad-hoc Networks (VANETs). Over the last decade, many models throughout the communication stack have been presented, which have increased the degree of realism that can be achieved with popular simulation frameworks. Nevertheless, the three-dimensional aspects of many real-world traffic situations barely find consideration. In this paper, we present a holistic approach to simulate large-scale three-dimensional VANET scenarios. We briefly summarize our previously presented models covering different aspects of communication in 3D scenarios, including an environmental diffraction model, an n-ray ground interference model, and the consideration of multi-floor communication. We then describe the principle of a model selector, which applies the appropriate models depending on the environment of the currently transmitted packet. Subsequently, we use the outlined methodology implemented in our Veins 3D framework to simulate a large urban reference scenario. The results differ significantly from comparable 2D simulations, demonstrating the necessity of three-dimensional considerations. However, they also show strongly increased execution times. Therefore, we further suggest different approaches to improve the simulation performance. Based on these optimizations, simulation durations in the same order of magnitude as a comparable 2D simulation can be achieved.