Test Point Selection Research Articles

Milling Stability Modeling by Sample Partitioning with Chatter Frequency-Based Test Point Selection

This paper describes a sample partitioning approach to retain or reject samples from an initial distribution of stability maps using milling test results. The stability maps are calculated using distributions of uncertain modal parameters that represent the tool tip frequency response functions and cutting force model coefficients. Test points for sample partitioning are selected using either (1) the combination of spindle speed and mean axial depth from the available samples that provides the high material removal rate, or (2) a spindle speed based on the chatter frequency and mean axial depth at that spindle speed. The latter is selected when an unstable (chatter) result is obtained from a test. Because the stability model input parameters are also partitioned using the test results, their uncertainty is reduced using a limited number of tests and the milling stability model accuracy is increased. A case study is provided to evaluate the algorithm.

A Test Point Selection Method Based on Fault Response Matrices Framework

This paper presents a novel method for test point selection based on fault response matrices framework. The main purpose of this method is to minimize the set of test points by constructing a fault response matrices framework, to resolve fault effects vanishing and fault detection degradation, and to achieve fewer test point set and higher fault coverage. According to the analysis of the fault response matrices and their derived matrices, the efficiency of the response of each node on the fault is ranked and a new propagation cone for undetectable faults is defined to narrow candidate test point set. We propose a custom testability measure to evaluate the impact of candidate test points on design, and obtain an optimal configuration of the most efficient test points accurately and rapidly. This methodology fully considers the correlation among test points, faults, and test vectors across internal signals resolving timing constraints to increase faults coverage. It can narrow the hard-to-test areas of random test patterns, and reduce the test vector set volume of deterministic test patterns. Our experimental results demonstrate the superiority of the proposed method: higher test coverage, minimum test time, fewer deterministic test patterns, and smaller hardware overhead.

Design of a wearable multi-point temperature monitoring system – practical application in waist temperature monitoring

PurposeHuman skin temperature data can provide reference advice for diagnosing many diseases, but current wearable skin temperature monitoring systems have few points and may miss temperature information in critical areas. This paper aims to develop a wearable system that can be used for local temperature monitoring and restore better the actual state of local human temperature by exploring ways to extend more temperature measurement points. This will provide better assistance in developing medical targeting and intelligent clothing.Design/methodology/approachThe temperature measurement system contains modules for temperature monitoring, digital-to-analog conversion and regulated power supply, enabling fast reading of 12 channels of monitoring data. The microprocessor unit is the STM32F407. The instructions and control modes are written in C. The waist area was chosen as the monitoring area because it is susceptible to temperature, and many diseases are associated with skin temperature. Twelve points, including temperature-related acupuncture points and heat-sensitive points, were selected for testing and the data results agreed well with the infrared imaging results.FindingsThe waist is selected as the monitoring object, and an easy-to-wear waist temperature monitoring belt is designed to verify the application value of the system. The development of the system provides reference suggestions for the exploration of multi-point temperature monitoring systems and the integration capabilities of temperature measurement modules in wearable multifunctional systems.Practical implicationsIn addition to waist temperature monitoring, the wearable temperature measurement system developed in this study can also be applied to other body parts. In addition, the system can be efficiently and effectively combined with various garments, making it a useful tool for researching human skin temperature.Originality/valueThe wearable temperature monitoring system designed in this paper extends the number of temperature test points to 12. The number of test points covers as many localized body areas as possible to indeed reproduce the temperature distribution of the human body. In addition, the selection of test points combines medically relevant body points with physiologically relevant heat-sensitive areas, which makes the temperature measurement data more valuable.

Computational model of trachea-alveoli gas movement during spontaneous breathing

A computational model of the transport of gases involved in spontaneous breathing, from the trachea inlet to the alveoli was developed for healthy patients. Convective and diffusive transport mechanisms were considered simultaneously, using a diffusion coefficient (D) that has considered the four main species of gases present in the exchange carried out by the human lung, nitrogen (N2), oxygen (O2), carbon dioxide (CO2) and water vapor (H2O). A Matlab® script was programmed to simulate the trachea-alveolus gas exchange model under three respiratory frequencies: 12, 24 and 40 breaths per minute (BPM), each with three diaphragmatic movements of 2 cm, 4 cm, and 6 cm. During the simulations, the CO2 inlet concentrations in the alveoli and the O2 concentration at the inlet of the trachea were kept constant. A simplified but stable model of mass transport between the trachea and alveoli was obtained, allowing the concentrations to be determined dynamically at the selected test points in the airway.

Diagnostics of Large Non-Conductive Anti-Corrosion Coatings on Steel Structures by Means of Electrochemical Impedance Spectroscopy.

This paper proposes a testing methodology for barrier properties of large non-conductive anti-corrosion coatings on steel structures. Electrochemical impedance spectroscopy (EIS) was adapted to in situ testing of steel structures by using a prototypical flexible measuring probe and a gel electrolyte that filled the probe, to take measurements on any surface regardless of its position. The first stage of the testing methodology was to perform time-consuming impedance measurements and quick electromagnetic measurements of coating thickness at selected test points. The results were used to determine correlation relationships between the logarithm of the impedance modulus for the coating at a measuring frequency of 0.1 Hz measured with the EIS method and the average thickness of the coating measured with an electromagnetic thickness gauge. Quick electromagnetic measurements were performed in the second stage to specify thickness of the other surface of the steel structure coating. The barrier properties of this coating were identified on the basis of the determined correlation.

New digital testing for parametric fault detection in analog circuits using classified frequency-bands and efficient test-point selection

This paper presents a new parametric fault detection (PFD) approach for testing of linear analog circuits. It combines classified frequency-bands with amplitude weighting for fault controllability and test-points selection for fault observability. The test waveform sweeps on an applicable frequency-band instead of the whole band to stimulate parametric faults. The number of required samples is reduced, and the summation of samples from undesired bands is avoided. The test response is compacted for each band generating digital signature. The digital signature curve (DSC) is plotted for each component. A hybrid between MATLAB and PSPICE simulation is used to develop accurate worst case analysis (WCA). The relation between the classified DSC and the accurate WCA results in the enhanced PFD. It is found that the weighted sweeping-sinusoidal waveform is the best selection. The presented approach is applied to different linear analog benchmark circuits and shows the significant PFD improvement compared to previously published works.

Planning constant‐stress accelerated life tests with multiple stresses based on D‐optimal design

AbstractWith the rapid technological advances, products are becoming more reliable. Then, multistress accelerated life testing (MALT) has been adopted in engineering to obtain failure information in a limited time. In order to make the testing procedure more efficient, it is necessary to better design the test plan. However, to date, relevant research on planning of MALT is limited. Multiple stresses will lead to plenty of stress‐level combinations that require too much cost and time to implement. Besides, there may be interactions among multiple stresses, which need more experiments for parameter estimation. To solve these problems, we propose a novel planning method for constant‐stress MALT under lognormal distribution using D‐optimal design, which can reduce required test points efficiently and deal with second‐order effects in models. In ALT, the log‐linear model is often used to describe the life‐stress relationship. Hence, D‐optimal design is adopted in this paper to select test points from the whole test region. Then, optimal unit allocation plans are formulated under V/D‐optimality criterion, respectively, where type I and type II censoring are both discussed. A real case of light‐emitting device (LED) is presented to compare the proposed approach with other two existing methods. The results show that the proposed method performs better than other two existing methods both in prediction accuracy and estimation precision. Moreover, a sensitivity analysis reveals the robustness of the optimal plans determined by the proposed method.

A test point selection approach for DC analog circuits with large number of predefined faults

Test point selection is an important stage in analog circuits fault diagnosis. In this paper, a test point selection method is proposed that is suitable for large numbers of predefined faults in DC analog circuits using the technique of constructing a fault dictionary for each component. Main idea is selecting a test point set with minimum amount of overlap between fault and no-fault regions for each component. A combined exclusive-inclusive algorithm is applied on each fault dictionary and using the achieved information, a grade is given to each test point. Then the test points with grades lower than a threshold value are eliminated and a decision guide is provided for tester to select final test point set. Applying this method on a benchmark circuit is eliminating 22% of test points and the accuracy metrics of proposed approach is comparable with using all of the test points. The results show that by eliminating 56% of the test points, the accuracy metrics just drops about 4%.

РOSSIBILITY OF USE AND ADAPTATION OF GENETIC ALGORITHMS FOR RATIONAL DESIGN OF TOOTHED HELICAL REDUCERS AND GEARBOXES

The article is devoted to the possibility of using and adapting genetic algorithms (GA) for rational design of cylindrical reducers gearboxes. The main theory of the LP-search method are considered, which allow to evaluate the possibilities of this method and analyze the prospects of its expansion using the ideology of GA. The basic theory concerning GA are considered. The main differences between GA and classical optimization methods are given. The algorithmic scheme of classical GA is described. An analysis of the main genetic selection of parents, cross-breeding and mutations is given. An estimation of the basic genetic operators is made on their productivity and convenience of use, and determined by their choice for further work. Possible variants of modifications of GA sequences are considered considering the features of the problem of rational design of geared cylindrical gearboxes. The first one provides an algorithm that allows a significant increase in the number of viable individuals, that is, test points satisfying the numerical and functional limitations of the data, thereby offsetting the lack of limitation on the maximum possible number of test points in the LP-search. The following describes an algorithm that focuses primarily on the selection of more qualitative test points and the creation of an appropriate population that is inherent in genetic-evolutionary algorithms (GEAs). It is based on the operator - the withdrawal of less quality points, as well as the mandatory use of the operator mutation. Thus, a theoretical basis for further testing of proposed modifications of GA algorithms was created.

Optimum test point selection method for analog fault dictionary techniques

Fault dictionary has two types of online and offline calculation. Online calculation is simple, but offline is excessive and time-consuming. In order to reduce the computation time and dimension of fault dictionary, optimal test points selection is very essential. So, the main purpose, fault isolation, is achieved in a short time. In this paper a new efficient method to select an optimum set of test points for fault diagnosis is proposed. At the first, a fault-isolated table is constructed to pick out the special test points from the candidates. Then, the isolation ability of special test points has been considered. If they can’t isolate all of faults, the fault dictionary is rearranged. Therefore, the special test points and isolated faults are eliminated from the table of fault dictionary. In this step, the test point with more single fault is added to special test points. This step is repeated to isolate all of faults. The proposed method is applied on two-stage operational amplifier. By this method, all of faults for this structure are isolated. The computation requirements are very simple than the other methods. In this circuit, the 0.045 s is needed to isolate all of circuit faults. According to the results, it’s clear that the method is a good solution to minimize the size of the test points set. Also, it can be a practical method for medium and large scale systems.

Kinetic study of carbon monoxide methanation over mesoporous Ni-Mo catalyst prepared by a hydrothermal method

The kinetics of carbon monoxide methanation over Ni-Mo-SiO2 catalyst were studied. The model was developed based on catalyst tests carried out in a fixed-bed reactor at a reaction temperature varied from 300 °C to 450 °C under a pressure from 0.1 to 1.5 MPa with a weight hourly space velocity of 60,000 mL h−1 g−1. An orthogonal design method was adopted to select test points with temperature, pressure, and feed compositions as factors. Based on the experimental observations, a Langmuir–Hinshelwood equation kinetic model was formulated and its parameters were estimated by fitting the experimental data implemented in MATLAB. The activation energy for the formation of CH4 was 45.4 kJ mol−1 and comparing the experimental and model-predicted data showed that the proposed model gives a reasonable fit with an average absolute relative deviation of ±9.8%.

Application of Pattern Recognition Analysis to Optimize Hemifield Asymmetry Patterns for Early Detection of Glaucoma.

PurposeTo assess the diagnostic utility of a new hemifield asymmetry analysis derived using pattern recognition contrast sensitivity isocontours (CSIs) within the Humphrey Field Analyzer (HFA) 24-2 visual field (VF) test grid. The performance of an optimal CSI-derived map was compared against a commercially available clustering method (Glaucoma Hemifield Test, GHT).MethodsFive hundred VF results of 116 healthy subjects were used to determine normative distribution limits for comparisons. Pattern recognition analysis was applied to HFA 24-2 sensitivity data to determine CSI theme maps delineating clusters for hemifield comparisons. Then, 1019 VF results from 228 glaucoma patients were assessed using different clustering methods to determine the true-positive rate. We also assessed additional 354 VF results of 145 healthy subjects to determine the false-positive rate.ResultsThe optimum clustering method was the CSI-derived seven-theme class map, which identified more glaucomatous VFs compared with the GHT map. The seven-class theme map also identified more cases compared with the five-, six-, and eight-class maps, suggesting no effect of number of clusters. Integrating information regarding the location of glaucomatous defects to the CSI clusters did not improve detection rate.ConclusionsA clustering map derived using CSIs improved detection of glaucomatous VFs compared with the currently available GHT. An optimized CSI-derived map may serve as an additional means to aid earlier detection of glaucoma.Translational RelevancePattern recognition–derived theme maps provide a means for guiding test point selection for asymmetry analysis in glaucoma assessment.

Effective inpainting method for natural textures with gradually changed illumination

Natural textures with gradually changed illumination bring great troubles to the field of image inpainting. Using the improved dynamical modeling approach, an energy function model gradually changed from the center to the boundary of data missing region of image is established. On this basis, a gradually changed directional priority function is proposed to ensure the gradual propagation of texture synthesis. In addition, to achieve the feasible propagation of the boundary between different textural regions, the relative test point selection, as well as energy function modeling approach, is also discussed for different cases. Besides, the established energy function models are theoretically evaluated to demonstrate their accuracy in images. Experimental results show the effectiveness of the proposed approach in the natural images with gradually changed illumination.

Comparison and Discussion of National/Military Standards Related to Flow Measurement of Medical Injection Pump

Medical injection pump is a commonly used clinical equipment with high risk. Accurate detection of flow is an important aspect to ensure its reliable operation. In this paper, we carefully studied and analyzed the flow detection methods of three standards being used in medical injection pump detection in our country. The three standards were compared from the aspects of standard device, flow test point selection, length of test time and accuracy judgment. The advantages and disadvantages of these standards were analyzed and suggestions for improvement were put forward.

Intrinsic Kinetics Study of CO Methanation on Ni-Mo-SiO<sub>2</sub> Catalyst Prepared by Hydrothermal Method

A comprehensive kinetic model for methanation of syngas on Ni-Mo-SiO2catalyst was developed on a fixed bed reactor data. The CO and H2conversion, methane selectivity and yield were obtained in a wide range of operating conditions including 300 < T < 450°C, 1 < H2/CO <4 and 0.1 < P < 1.5 MPa with the total weight hourly space velocity (WHSV) of 60000 ml/h/g. A 6-step reaction scheme defined to the description of a reaction network that considers both catalytic and gas-phase as well as primary and consecutive reaction steps to predict the performance of the syngas methantion. Orthogonal design method was adopted to select test points with temperature, pressure and feed compositions as factors and the kinetic rates involved Langmuir – Hinshelwood equation kinetic model. The kinetic rate parameters were estimated using the Least Square Method by MATLAB. Comparing the experimental and model predicted data showed that presented model has a reasonable fit between the experimental data and the predicted values with average absolute relative deviation of ±9.8%.

Оценка достоверности результатов измерений температуры при поверке пирометров

The feasibility of assessing the validity of calibration results in the development of new methods of calibration and comparison with existing methods substantiates. The reliability of calibration of infrared thermometers TESTO 830 and Sight when you used different standards of precision was evaluated. The results obtained by simulation (Monte Carlo). Selection of test points in the measurement range of the infrared thermometers discussed. The study was conducted on the basis of materials of calibration in FBU «Novosibirskiy CSM». The proposed methodology can be used in the analysis of existing and development of new methods of calibration of measuring instruments.

Test Point Selection Method for Analog Circuit Fault Diagnosis Based on Similarity Coefficient

The demand for testability analysis has increased with the integration densities and complexity of circuits. As an important part of testability analysis, the test point selection method needs to be researched in depth. A new similarity coefficient criterion is proposed to determine the fault isolation degree because output responses of a circuit with component tolerance are approximately subject to the normal distribution. Then, a new test point selection method is proposed based on the fault-pair similarity coefficient criterion information table. Simulation experiments are used to validate the accuracy of the proposed method in terms of the optimum test point set and fault isolation degree. The results show that the proposed method improves the performance of test point selection by comparing with the other reported methods.

Research and design for optimal position of electrocardio-electrodes in monitoring clothing for men

In order to reduce the mortality rate of cardiovascular disease patients effectively, improve the electrocardiogram (ECG) accuracy of signal acquisition, and reduce the influence of motion artifacts caused by the electrodes in inappropriate location in the clothing for ECG measurement, we in this article present a research on the optimum place of ECG electrodes in male clothing using three-lead monitoring methods. In the 3-lead ECG monitoring clothing for men we selected test points. Comparing the ECG and power spectrum analysis of the acquired ECG signal quality of each group of points, we determined the best location of ECG electrodes in the male monitoring clothing. The electrode motion artifacts caused by improper location had been significantly improved when electrodes were put in the best position of the clothing for men. The position of electrodes is crucial for ECG monitoring clothing. The stability of the acquired ECG signal could be improved significantly when electrodes are put at optimal locations.

KKCV-GA-Based Method for Optimal Analog Test Point Selection

A novel diagnosis oriented method for optimal analog test point selection is proposed. The method uses a kernel density estimation on $K$ -nearest neighbors-based cross-validation to evaluate the diagnostic capability of the selected test points, and then employs a genetic algorithm to search the quasi-optimal solution with the maximum diagnostic capability under a limited number of test points. Experimental results show that better solutions in terms of the diagnostic accuracies of the advanced intelligent classifiers can be obtained, and the knowledge of critical test points is revealed, which supports further improvement of the optimization, not only to increase the probability of reaching the global optimal solutions but also to reduce the time costs. In addition, with the precise estimation of the diagnostic capability, the proposed method can also be used to verify the results produced by other methods in this field.

Analog Circuit Test Point Selection Incorporating Discretization-Based Fuzzification and Extended Fault Dictionary to Handle Component Tolerances

Analog circuit test point selection aims to find the least number of test points that can isolate all the fault modes (including the fault-free case). The fault dictionary, which uses the integer-valued codes to represent the diagnosability of a specific test point, is very popular and saves computation efforts. However, the classical fault dictionary has a limited ability to handle the component tolerances and continuous-valued monitoring variables. To solve the problem, the approach of clustering-based discretization (CBD) is used to abstract the information of data samples distribution. We also develop a new fault dictionary construction technique called extended fault dictionary (EFD). An element of EFD is a set containing either a single integer code or multiple integer codes. The fault isolation rules are redefined, and a novel entropy measure is created in line with CBD of the continuous values. The practical test point selection procedures are presented, which avoids the likelihood to include a redundant test point. Finally, two application studies of circuit test point election are presented, showing that the proposed method provides an effective implementation option for the engineering practice of circuit diagnosis.