Semirings which have linearly ordered prime ideals

As a generalization of valuation semirings, the main purpose of this paper is to investigate those semirings that their prime ideals are totally ordered by inclusion. First, we prove that the prime ideals of a semiring $S$ are linearly ordered if and only if for each $x,y \in S$, there is a positive integer $n$ such that either $x|y^n$ or $y|x^n$. Then we introduce and characterize pseudo-valuation semidomains. It is shown that prime ideals of pseudo-valuation semidomains and also divided ones are linearly ordered.Comment: Some new references added. Some minor typos edite

Studies of Time Variations of the Magnetic Field in the nEDM@SNS Experiment

It is thought that equal quantities of matter and antimatter were generated at the moment of the Big Bang. However, observations of the Universe show that there is a significant excess of matter over antimatter. The matter-antimatter asymmetry in the Universe (baryon to photon ratio) is observed to be of the order of 10-10 [1]. Baryogenesis is a possible explanation for the matter-antimatter asymmetry of the universe. In 1967, Sakharov proposed three criteria necessary for Baryogenesis. The three conditions are: 1) baryon number violation, 2) C and CP violation and 3) departure from thermal equilibrium. However, the Standard Model\u27s prediction of C and CP violation is not enough to explain the observed matter-antimatter asymmetry. Physicists have been seeking for Standard Model (SM) modifications in attempt to discover an explanation. A nonzero neutron electric dipole moment (nEDM) violates the T and P symmetries, which leads to CP violation due to CPT conservation. In 1951, Oak Ridge hosted the first experiment to search for a neutron EDM (dn) that led to dn = -(0.1 ± 2.4) * 10-20 e.cm. Later, in 1977, the improved method\u27s sensitivity reached  dn = 3 *10-24 e.cm (90% CL). In 2006, Baker et al. at the Institute Laue-Langevin cut the upper limit by almost two orders of magnitude. The ILL apparatus deployed by the RAL/Sussex/ILL collaboration at the Paul Scherrer Institut (PSI) in 2020 established the current limitations of the nEDM |dn| \u3c 1.8 * 10-26 e.cm (90% CL). A cryogenic device based on a unique idea devised by Golub and Lamoreaux [2] is being constructed at Oak Ridge National Laboratory\u27s Spallation Neutron Source (SNS) to improve the sensitivity of nEDM studies. The experiment uses superfluid 4He to produce a high density of Ultra-Cold Neutrons (UCN). The Larmor precession of the UCNs is then monitored by the scintillation signals due to the spin-dependent interaction rate of UCNs and 3He atoms. One of the central problems to any nEDM experiment is the stability of the magnetic field. Hence, in general, the experiment depends on a precise system of magnetometers that monitor the average magnetic field over the region where the neutrons precess. Accordingly, the nEDM@SNS experiment takes advantage of polarized 3He atoms as a co-magnetometer via detection of the precessing 3He magnetization in SQUID pickup loops. This document will outline the simulation of scintillation and SQUID signals in the presence of time-varying magnetic fields, and developing data analysis techniques to detect these time-variations and correct their effect from the nEDM measurement

Margins of postural stability in Parkinson’s disease: an application of control theory

Introduction: Postural instability is a restrictive feature in Parkinson’s disease (PD), usually assessed by clinical or laboratory tests. However, the exact quantification of postural stability, using stability theorems that take into account human dynamics, is still lacking. We investigated the feasibility of control theory and the Nyquist stability criterion—gain margin (GM) and phase margin (PM)—in discriminating postural instability in PD, as well as the effects of a balance-training program.Methods: Center-of-pressure (COP) data of 40 PD patients before and after a 4-week balance-training program, and 20 healthy control subjects (HCs) (Study1) as well as COP data of 20 other PD patients at four time points during a 6-week balance-training program (Study2), collected in two earlier studies, were used. COP was recorded in four tasks, two on a rigid surface and two on foam, both with eyes open and eyes closed. A postural control model (an inverted pendulum with a Proportional-integral-derivative (PID) controller and time delay) was fitted to the COP data to subject-specifically identify the model parameters thereby calculating |GM| and PM for each subject in each task.Results: PD patients had a smaller margin of stability (|GM| and PM) compared with HCs. Particularly, patients, unlike HCs, showed a drastic drop in PM on foam. Clinical outcomes and margins of stability improved in patients after balance training. |GM| improved early in week 4, followed by a plateau during the rest of the training. In contrast, PM improved late (week 6) in a relatively continuous-progression form.Conclusion: Using fundamental stability theorems is a promising technique for the standardized quantification of postural stability in various tasks

Experimental investigations on the effects of grid-screen, sand bed, and nozzle orientation on the dynamics of bubble plumes

A bubble plume is defined as a column of air that flows through a liquid ambient due to the density difference between air and the ambient liquid. Bubble plumes have been utilized in wastewater treatment and oxygen transfer in civil and environmental engineering projects. Based on the injection pressure of air flow, bubble plumes can be converted to jet plumes or bubbly jets. A bubble plume is generated by the injected pressurized air/gas, and a bubbly jet is generated by injection of gas-liquid mixture in the ambient. In addition, bubble plumes can be generated by injecting air through a nozzle, airborne stone, or a group of diffusers into the ambient water. Bubble plumes are classified as two-phase air-liquid flow in which the ambient hydrodynamics and initial conditions dictate the motion of air bubbles and their sizes. Bubble plumes are extensively used in civil, environmental, and chemical engineering fields in many different industrial applications (Beutel et al., 2008). In recent years, there has been an increasing interest in using bubble plumes for mixing or aeration in lakes to improve water quality by adding oxygen. [...

cGAN-Based High Dimensional IMU Sensor Data Generation for Therapeutic Activities

Human activity recognition is a core technology for applications such as rehabilitation, ambient health monitoring, and human-computer interactions. Wearable devices, particularly IMU sensors, can help us collect rich features of human movements that can be leveraged in activity recognition. Developing a robust classifier for activity recognition has always been of interest to researchers. One major problem is that there is usually a deficit of training data for some activities, making it difficult and sometimes impossible to develop a classifier. In this work, a novel GAN network called TheraGAN was developed to generate realistic IMU signals associated with a particular activity. The generated signal is of a 6-channel IMU. i.e., angular velocities and linear accelerations. Also, by introducing simple activities, which are meaningful subparts of a complex full-length activity, the generation process was facilitated for any activity with arbitrary length. To evaluate the generated signals, besides perceptual similarity metrics, they were applied along with real data to improve the accuracy of classifiers. The results show that the maximum increase in the f1-score belongs to the LSTM classifier by a 13.27% rise when generated data were added. This shows the validity of the generated data as well as TheraGAN as a tool to build more robust classifiers in case of imbalanced data problem

Evaluating a new verbal working memory-balance program: a double-blind, randomized controlled trial study on Iranian children with dyslexia

Abstract: Background: It is important to improve verbal Working Memory (WM) in reading disability, as it is a key factor in learning. There are commercial verbal WM training programs, which have some short-term effects only on the verbal WM capacity, not reading. However, because of some weaknesses in current verbal WM training programs, researchers suggested designing and developing newly structured programs that particularly target educational functions such as reading skills. In the current double-blind randomized clinical trial study, we designed a new Verbal Working Memory-Balance (VWM-B) program which was carried out using a portable robotic device. The short-term effects of the VWM-B program, on verbal WM capacity, reading skills, and postural control were investigated in Iranian children with developmental dyslexia. Results: The effectiveness of the VWM-B program was compared with the VWM-program as a traditional verbal WM training. In comparison with VWM-program, the participants who received training by the VWM-B program showed superior performance on verbal WM capacity, reading skills, and postural control after a short-term intervention. Conclusions: We proposed that the automatized postural control resulting from VWM-B training had a positive impact on improving verbal WM capacity and reading ability. Based on the critical role of the cerebellum in automatizing skills, our findings support the cerebellar deficit theory in dyslexia. Trial registration: This trial was (retrospectively) registered on 8 February 2018 with the Iranian Registry of Clinical Trials (IRCT20171219037953N1)

Power System Dynamic Stability Enhancement Using a New PID Type PSS 1

Abstract: Power System Stabilizers (PSS) are used to generate supplementary damping control signals for the excitation system in order to damp the Low Frequency Oscillations (LFO) of the electric power system. The PSS is usually designed based on classical control approaches but this Conventional PSS (CPSS) has some problems. To overcome the drawbacks of CPSS, numerous techniques have been proposed in literatures. In this paper a PID type PSS (PID-PSS) is considered for damping electric power system oscillations. The parameters of this PID type PSS (PID-PSS) are tuned based on Hybrid Genetic Algorithm optimization method. The proposed PID-PSS is evaluated against the conventional power system stabilizer (CPSS) at a single machine infinite bus power system considering system parametric uncertainties. The simulation results clearly indicate the effectiveness and validity of the proposed method