Aging effect and test-retest reliability of the sinusoidal harmonic acceleration test and velocity step test using nanotorque rotatory chair

Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests.

Test-retest reliability of the Mini Nutritional Assessment–Short Form(MNA-SF)in older patients undergoing cardiac rehabilitation

Malnutrition is described as a state of insufficient intake of energy,protein and other nutrients leading to changes in body composition(weight loss,reduced fat-free mass)as well as adverse functional and clinical outcomes.[1]Depending on the assessments and definition used,the prevalence in older patients ranges between 12%in communitydwelling adults to 60%of patients in geriatric care facilities.[2–5]Older populations are at high risk of nutritional deficiencies because of risk factors such as multimorbidity,polypharmacy,cognitive and physical decline,poor appetite,depressive syndromes and socioeconomic changes.[4,6].

Test-Retest Reliability, Convergent Validity and Practice Effects of the RBANS in a Memory Clinic Setting: A Pilot Study

This pilot study examined the psychometric properties and clinical utility of a brief neuropsychological instrument (Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The test-retest reliability, practice effects and convergent validity of RBANS were examined in participants without objective cognitive impairment. The tests were administered at two time points at approximately a two weeks’ interval, with 30 cognitively intact participants with a mean age of 63.3 ± 5.8 years. Adequate test-retest reliabilities were found for RBANS subtests, index and total scale scores with significant gain scores in immediate memory and visuospatial function. The RBANS showed good convergent validity and the RBANS supplemented with executive and language measures (Colour Trails Test and 30-item modified Boston Naming Test, respectively) demonstrated excellent convergent validity with a formal neuropsychological battery. This pilot study has provided the preliminary evidence of reliability and convergent validity of the RBANS. Additionally, it also provides insight on the practice effects so that clinicians may assess significant changes in RBANS subtests and domain indexes for clinical practice.

Test-Retest Reliability of Sensory Evoked Potentials in Low-Functioning Autism: A Case Report

Sensory abnormalities are common in individuals with autism spectrum disorders (ASD) but are often difficult to assess using standard behavioral methods. Evoked potentials provide objective, non-invasive electrophysiological measures of neural sensory processing that could be useful for clinical and investigative studies of individuals with low-functioning autism who are unable to perform behavioral testing. Despite increased use, the reliability of sensory evoked potentials has not been established for individuals with low-functioning autism. Establishing reliability is important for validating the utility of sensory evoked potentials. In this study, we explored the feasibility of assessing the test-retest reliability of sensory evoked potentials using repeat recordings, acquired over 2.5- and 6-month intervals, from a minimally verbal adult with low-functioning autism. Repeat auditory and visual evoked potential recordings showed high test-retest reliability, with cross-correlation coefficients ≥ 0.80. This case demonstrates the feasibility of establishing test-retest reliability for individuals with low-functioning autism and supports the utility of sensory evoked potentials in clinical and investigative ASD studies.

On the relationship between imprint and reliability in Hf_(0.5)Zr_(0.5)O_(2) based ferroelectric random access memory

The detrimental effect of imprint,which can cause misreading problem,has hindered the application of ferroelectric HfO_(2).In this work,we present results of a comprehensive reliability evaluation of Hf_(0.5)Zr_(0.5)O_(2)-based ferroelectric random access memory.The influence of imprint on the retention and endurance is demonstrated.Furthermore,a solution in circuity is pro-posed to effectively solve the misreading problem caused by imprint.

Reliability Assessment of a New General Matching Composed Network

The reliability of a network is an important indicator for maintaining communication and ensuring its stable operation. Therefore, the assessment of reliability in underlying interconnection networks has become an increasingly important research issue. However, at present, the reliability assessment of many interconnected networks is not yet accurate,which inevitably weakens their fault tolerance and diagnostic capabilities. To improve network reliability,researchers have proposed various methods and strategies for precise assessment. This paper introduces a novel family of interconnection networks called general matching composed networks(gMCNs), which is based on the common characteristics of network topology structure. After analyzing the topological properties of gMCNs, we establish a relationship between super connectivity and conditional diagnosability of gMCNs. Furthermore, we assess the reliability of g MCNs, and determine the conditional diagnosability of many interconnection networks.

Saddlepoint Approximation Method in Reliability Analysis:A Review

The escalating need for reliability analysis(RA)and reliability-based design optimization(RBDO)within engineering challenges has prompted the advancement of saddlepoint approximationmethods(SAM)tailored for such problems.This article offers a detailed overview of the general SAM and summarizes the method characteristics first.Subsequently,recent enhancements in the SAM theoretical framework are assessed.Notably,the mean value first-order saddlepoint approximation(MVFOSA)bears resemblance to the conceptual framework of the mean value second-order saddlepoint approximation(MVSOSA);the latter serves as an auxiliary approach to the former.Their distinction is rooted in the varying expansion orders of the performance function as implemented through the Taylor method.Both the saddlepoint approximation and third-moment(SATM)and saddlepoint approximation and fourth-moment(SAFM)strategies model the cumulant generating function(CGF)by leveraging the initial random moments of the function.Although their optimal application domains diverge,each method consistently ensures superior relative precision,enhanced efficiency,and sustained stability.Every method elucidated is exemplified through pertinent RA or RBDO scenarios.By juxtaposing them against alternative strategies,the efficacy of these methods becomes evident.The outcomes proffered are subsequently employed as a foundation for contemplating prospective theoretical and practical research endeavors concerning SAMs.The main purpose and value of this article is to review the SAM and reliability-related issues,which can provide some reference and inspiration for future research scholars in this field.

Probabilistic-Ellipsoid Hybrid Reliability Multi-Material Topology Optimization Method Based on Stress Constraint

This paper proposes a multi-material topology optimization method based on the hybrid reliability of the probability-ellipsoid model with stress constraint for the stochastic uncertainty and epistemic uncertainty of mechanical loads in optimization design.The probabilistic model is combined with the ellipsoidal model to describe the uncertainty of mechanical loads.The topology optimization formula is combined with the ordered solid isotropic material with penalization(ordered-SIMP)multi-material interpolation model.The stresses of all elements are integrated into a global stress measurement that approximates the maximum stress using the normalized p-norm function.Furthermore,the sequential optimization and reliability assessment(SORA)is applied to transform the original uncertainty optimization problem into an equivalent deterministic topology optimization(DTO)problem.Stochastic response surface and sparse grid technique are combined with SORA to get accurate information on the most probable failure point(MPP).In each cycle,the equivalent topology optimization formula is updated according to the MPP information obtained in the previous cycle.The adjoint variable method is used for deriving the sensitivity of the stress constraint and the moving asymptote method(MMA)is used to update design variables.Finally,the validity and feasibility of the method are verified by the numerical example of L-shape beam design,T-shape structure design,steering knuckle,and 3D T-shaped beam.

A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix multiplication.The expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is achieved.For a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray cells.The aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural design.With cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is conducted.To maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are constructed.The variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization algorithm.The vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic distance.Finally,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

On the Application of Mixed Models of Probability and Convex Set for Time-Variant Reliability Analysis

In time-variant reliability problems,there are a lot of uncertain variables from different sources.Therefore,it is important to consider these uncertainties in engineering.In addition,time-variant reliability problems typically involve a complexmultilevel nested optimization problem,which can result in an enormous amount of computation.To this end,this paper studies the time-variant reliability evaluation of structures with stochastic and bounded uncertainties using a mixed probability and convex set model.In this method,the stochastic process of a limit-state function with mixed uncertain parameters is first discretized and then converted into a timeindependent reliability problem.Further,to solve the double nested optimization problem in hybrid reliability calculation,an efficient iterative scheme is designed in standard uncertainty space to determine the most probable point(MPP).The limit state function is linearized at these points,and an innovative random variable is defined to solve the equivalent static reliability analysis model.The effectiveness of the proposed method is verified by two benchmark numerical examples and a practical engineering problem.

Efficient slope reliability analysis under soil spatial variability using maximum entropy distribution with fractional moments

Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty are synthesized in the so-called probability of failure.This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint.In view of this issue,this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments.The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion.Then,failure probabilities are estimated employing maximum entropy distribution with fractional moments.The application of the proposed approach is examined with two examples:a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope.The results show that the proposed approach has excellent accuracy and high efficiency,and it can be applied straightforwardly to similar geotechnical engineering problems.

System Reliability Analysis Method Based on T-S FTA and HE-BN

For high-reliability systems in military,aerospace,and railway fields,the challenges of reliability analysis lie in dealing with unclear failure mechanisms,complex fault relationships,lack of fault data,and uncertainty of fault states.To overcome these problems,this paper proposes a reliability analysismethod based on T-S fault tree analysis(T-S FTA)and Hyper-ellipsoidal Bayesian network(HE-BN).The method describes the connection between the various systemfault events by T-S fuzzy gates and translates them into a Bayesian network(BN)model.Combining the advantages of T-S fault tree modeling with the advantages of Bayesian network computation,a reliability modeling method is proposed that can fully reflect the fault characteristics of complex systems.Experts describe the degree of failure of the event in the form of interval numbers.The knowledge and experience of experts are fused with the D-S evidence theory to obtain the initial failure probability interval of the BN root node.Then,the Hyper-ellipsoidal model(HM)constrains the initial failure probability interval and constructs a HE-BN for the system.A reliability analysismethod is proposed to solve the problem of insufficient failure data and uncertainty in the degree of failure.The failure probability of the system is further calculated and the key components that affect the system’s reliability are identified.The proposedmethod accounts for the uncertainty and incompleteness of the failure data in complex multi-state systems and establishes an easily computable reliability model that fully reflects the characteristics of complex faults and accurately identifies system weaknesses.The feasibility and accuracy of the method are further verified by conducting case studies.

Reliability-BasedModel for Incomplete Preventive ReplacementMaintenance of Photovoltaic Power Systems

At present,the operation and maintenance of photovoltaic power generation systems mainly comprise regular maintenance,breakdown maintenance,and condition-based maintenance,which is very likely to lead to over-or under-repair of equipment.Therefore,a preventive maintenance and replacement strategy for PV power generation systems based on reliability as a constraint is proposed.First,a hybrid failure function with a decreasing service age factor and an increasing failure rate factor is introduced to describe the deterioration of PV power generation equipment,and the equipment is replaced when its reliability drops to the replacement threshold in the last cycle.Then,based on the reliability as a constraint,the average maintenance cost and availability of the equipment are considered,and the non-periodic incomplete maintenance model of the PV power generation system is established to obtain the optimal number of repairs,each maintenance cycle and the replacement cycle of the PV power generation system components.Next,the inverter of a PV power plant is used as a research object.The model in this paper is compared and analyzed with the equal cycle maintenance model without considering reliability and the maintenance model without considering the equipment replacement threshold,Through model comparison,when the optimal maintenance strategy is(0.80,4),the average maintenance cost of this paper’s model are decreased by 20.3%and 5.54%and the availability is increased by 0.2395% and 0.0337%,respectively,compared with the equal-cycle maintenance model without considering the reliability constraint and the maintenance model without considering the equipment replacement threshold.Therefore,this maintenance model can ensure the high reliability of PV plant operation while increasing the equipment availability to improve the system economy.

A Generic and Reliable Land Acquisition Protocol Implementation for Sub-Saharan Africa Countries

Land acquisition is subject of many frauds worldwide. In Africa countries, land acquisition frauds are a real curse. Main reasons of the high land acquisition frauds in Africa are a lack of a reliable land acquisition protocol implementation, no centralized information system that records land transactions and integrates all actors, lack of education about the acquisition protocol and lack of applied sanctions in case of frauds. As of sanctions, the issue is bound to the corruption plague in Africa. Authorities that are supposed to rule the laws are not well paid and are part of the corruption scheme. Most frequent frauds are multiple sales of the same land, falsified land title, false owner identification. In Africa, a land belongs generally to the first residents of the area. To claim ownership of a land, an owner should be recognized by the rural or city authorities. To achieve this recognition, he must obtain from those authorities an attribution letter. The author proposed a complete and reliable land acquisition protocol named ACLAP (Africa Countries Land Acquisition Protocol). The purpose of this paper is to explain the main components of the protocol implementation and show its efficiency when confronting fraud threats. In this paper, a Generic and Reliable Land Acquisition Protocol Implementation in Sub-Saharan Africa countries context is proposed. The platform keeps relevant land transaction information for administrators, managers, buyers, sellers, or for people consultation purpose. The application may be used in village, city, department, region, or country for land management decision making.

Evaluation of the Reliability of a System: Approach by Monte Carlo Simulation and Application

The objective of this paper is to evaluate the reliability of a system in its different states (absence of failures, partial failure and total failure) and to propose actions to improve this reliability by an approach based on Monte Carlo simulation. It consists of a probabilistic evaluation based on Markov Chains. In order to achieve this goal, the functionalities of Markov Chains and Monte Carlo simulation steps are deployed. The application is made on a production system. .

Test-Retest Reliability of Functional Magnetic Resonance Imaging Activation for a Vergence Eye Movement Task

Vergence eye movements are the inward and outward rotation of the eyes responsible for binocular coordination.While studies have mapped and investigated the neural substrates of vergence,it is not well understood whether vergence eye movements evoke the blood oxygen level-dependent signal reliably in separate experimental visits.The test-retest reliability of stimulus-induced vergence eye movement tasks during a functional magnetic resonance imaging(fMRI)experiment is important for future randomized clinical trials(RCTs).In this study,we established region of interest(ROI)masks for the vergence neural circuit.Twenty-seven binocularly normal young adults participated in two functional imaging sessions measured on different days on the same 3 T Siemens scanner.The fMRI experiments used a block design of sustained visual fixation and rest blocks interleaved between task blocks that stimulated eight or four vergence eye movements.The test-retest reliability of task-activation was assessed using the intraclass correlation coefficient(ICC),and that of spatial extent was assessed using the Dice coefficient.Functional activation during the vergence eye movement task of eight movements compared to rest was repeatable within the primary visual cortex(ICC=0.8),parietal eye fields(ICC=0.6),supplementary eye field(ICC=0.5),frontal eye fields(ICC=0.5),and oculomotor vermis(ICC=0.6).The results demonstrate significant test-retest reliability in the ROIs of the vergence neural substrates for functional activation magnitude and spatial extent using the stimulus protocol of a task block stimulating eight vergence eye movements compared to sustained fixation.These ROIs can be used in future longitudinal RCTs to study patient populations with vergence dysfunctions.

Frequency-Resolved Connectome Hubs and Their Test-Retest Reliability in the Resting Human Brain

Functional hubs with disproportionately extensive connectivities play a crucial role in global information integration in human brain networks.However,most resting-state functional magnetic resonance imaging(R-fMRI)studies have identified functional hubs by examining spontaneous fluctuations of the blood oxygen level-dependent signal within a typical low-frequency band(e.g.,0.01–0.08 Hz or 0.01–0.1 Hz).Little is known about how the spatial distributions of functional hubs depend on frequency bands of interest.Here,we used repeatedly measured R-fMRI data from 53 healthy young adults and a degree centrality analysis to identify voxelwise frequency-resolved functional hubs and further examined their test-retest reliability across two sessions.We showed that a wide-range frequency band(0.01–0.24 Hz)accessible with a typical sampling rate(fsample=0.5 Hz)could be classified into three frequency bands with distinct patterns,namely,low-frequency(LF,0.01–0.06 Hz),middle-frequency(MF,0.06–0.16 Hz),and high-frequency(HF,0.16–0.24 Hz)bands.The functional hubs were mainly located in the medial and lateral frontal and parietal cortices in the LF band,and in the medial prefrontal cortex,superior temporal gyrus,parahippocampal gyrus,amygdala,and several cerebellar regions in the MF and HF bands.These hub regions exhibited fair to good test-retest reliability,regardless of the frequency band.The presence of the three frequency bands was well replicated using an independent R-fMRI dataset from 45 healthy young adults.Our findings demonstrate reliable frequency-resolved functional connectivity hubs in three categories,thus providing insights into the frequency-specific connectome organization in healthy and disordered brains.

Test re-test reliability of virtual acoustic space identification (VASI) test in young adults with normal hearing

Background:Recent developments in virtual acoustic technology has levered promising applications in the field of auditory sciences,especially in spatial perception.While conventional auditory spatial assessment using loudspeakers,interaural differences and/or questionnaires are limited by the availability and cost of instruments,the use of virtual acoustic space identification(VASI)test has widespread applications in spatial test battery as it overcomes these constraints.Purpose:The lack of test-retest reliability data of VASI test narrows its direct application in auditory spatial assessment,which is explored in the present study.Methods:Data from 75 normal-hearing young adults(mean age:25.11 y±4.65 SD)was collected in three sessions:baseline,within 15 min of baseline(intra-session),and one week after baseline session(inter-session).Test-retest reliability was assessed using the intra-class correlation coefficient(ICC),coefficient of variation(CV),and cluster plots.Results:The results showed excellent reliability for both accuracy and reaction time measures of VASI,with ICC values of 0.93 and 0.87,respectively.The CV values for overall VASI accuracy and reaction time 9.66% and 11.88%,respectively.This was also complemented by the cluster plot analyses,which showed 93.33% and 96.00% of temporal stability in the accuracy and reaction time measures,indicative of high test-retest reliability of VASI test in auditory spatial assessment.Conclusions:The high temporal stability(test-retest reliability)of VASI test validates its application in spatial hearing test battery.

Reliable Space Pursuing for Reliability-based Design Optimization with Black-box Performance Functions

Reliability-based design optimization(RBDO) is intrinsically a double-loop procedure since it involves an overall optimization and an iterative reliability assessment at each search point.Due to the double-loop procedure, the computational expense of RBDO is normally very high.Current RBDO research focuses on problems with explicitly expressed performance functions and readily available gradients.This paper addresses a more challenging type of RBDO problem in which the performance functions are computation intensive.These computation intensive functions are often considered as a"black-box"and their gradients are not available or not reliable.On the basis of the reliable design space(RDS) concept proposed earlier by the authors, this paper proposes a Reliable Space Pursuing(RSP) approach, in which RDS is first identified and then gradually refined while optimization is performed.It fundamentally avoids the nested optimization and probabilistic assessment loop.Three well known RBDO problems from the literature are used for testing and demonstrating the effectiveness of the proposed RSP method.