Performance Verification Research Articles

A contribution to the debate on measurement uncertainty when using X-ray computing tomography

Currently, XCT metrological capabilities require further enhancement, due to the absence of a full traceability chain and the presence of different scan parameters that can significantly influence the process. In the last 10 years, substantial progress has been made towards an XCT standardised process for dimensional inspection. However, AM surface measurement and porosity characterisation have been shown to be different from dimensional inspection presenting differing problems. The scanned object for dimensional inspection is affected by XCT measurement uncertainties. These are controlled by the scan voxel size (magnification) and scan parameters and to a lesser extent the surface determination; however, porosity characterisation and surface measurement are greatly affected by the surface determination, in addition to the material type, magnification and scan parameters. To address some of these issues artefacts are used for performance verification of the measuring system and the identification of contributing errors; this is considered one of the essential steps in the metrological process, where true traceability is elusive. Measurement uncertainty is the key to evaluation of the quality of the measurement. In order to ensure measurement traceability, every result should be accompanied by an uncertainty statement. However, several diverse sources can cause uncertainty in the XCT measurements, making it very difficult to establish the overall uncertainty. Furthermore, because the XCT system is a multi-purpose device that can be used for internal and external and material measurements, the uncertainty can vary significantly. The current study evaluates the precision of XCT measurement of internal defects in additively manufactured components through the assessment of reproducibility and repeatability of the internal feature characterisation process. Several sources of variability were assessed: two different XCT machines, three different operators and four different surface determination thresholds. The main aim of the repeatability study was to identify the confidence in successive measurements when scanning under the same conditions. The reproducibility study was used to find the relationship between results when conditions are varied. The results of the repeatability study have a deviation from the reference value within 0.8 voxel, and for the reproducibility study has shown the deviation from the reference value is within 1.6 voxels, with some operators’ results’ less than one voxel from the reference value. The use of different scan parameters and specifically different spot sizes result in the result output deviation. All the operators chose an optimum ISO threshold value for surface determination based on a previously published methodology which was more than 50%, the closest results to the reference value were obtained from a 61% surface determination threshold. The custom ISO threshold method for surface determination could detect the cavities between the powder particles.

ESO-based adaptive event-triggered load following control design for a pressurized water reactor with samarium–promethium dynamics

Conventional control systems used in nuclear reactors rely on real-time information transmission between the controllers and the actuators, which is unnecessary and imposes a heavy communication burden. To this end, this paper proposes an extended state observer-based adaptive event-triggered control (ESO-AETC) scheme for the load following problem of a pressurized water reactor (PWR) in the presence of uncertainties and limited communication resources. Different from most of the previous controllers presented in the literature, the samarium–promethium dynamics are considered in the constructed PWR model in this paper. Based on the PWR model with the load-dependent parameters and the samarium–promethium dynamics, an ESO, which can estimate lumped uncertainties and unmeasured system states including the relative density of the delayed neutron precursor, the average fuel temperature, the xenon concentration, the iodine concentration, the samarium concentration, the promethium concentration, and the total reactivity, is designed. With the help of the ESO and the event-triggered techniques, an AETC scheme is developed to avoid the real-time communication in the controller-to-actuator channel of the PWR system. It is rigorously proved that the control error can converge to any prescribed residual set in a finite time according to Lyapunov stability theory, excluding the Zeno behavior. Finally, simulation studies involving comparisons with existing works, estimation performance verification, and sensitivity analysis are conducted to assess the proposed ESO-AETC scheme. Simulation results reveal that (1) relative to the pre-existing model-free controller (MFC) and the disturbance observer-based sliding mode controller (DO-SMC), the proposed ESO-AETC scheme is found to provide better load following performance with at least 56.12% lower maximum absolute error (MAE), at least 15.05% lower integral absolute error (IAE), and 87.58% reduced communication resources in the controller-to-actuator channel, (2) the ESO possesses strong estimation capability for system states and lumped uncertainties, and (3) the proposed ESO-AETC scheme yields a low sensitivity with respect to the change of the controller parameters.

Requirements of Standard Establishment for Lattice-type Bi-block Reinforced Concrete Sleepers

Lattice-type bi-block reinforced concrete (RC) sleepers have been widely used for cast-in-place concrete slab tracks. However, the standards for manufacturing, inspection, and performance verification of the lattice-type bi-block RC sleepers are not well established, even when such a sleeper is a critical component of the cast-in-place concrete slab track. Therefore, it is necessary to develop a new standard for lattice-type bi-block RC sleepers. In this study, the requirements for the relevant standard were investigated through literature review. Domestic and international standards pertaining lattice-type bi-block RC sleepers were summarized and compared with each other. Consequently, the requirements for standard establishment were proposed.

Calibration and Validation

Analytical instruments are used for a specific analysis of drugs and pharmaceuticals. So, regular performance verification are made to ensure that the instruments used in the analytical purpose should be properly validated and calibrated “To demonstrate that it is suitable for its intended use”.

Visual recognition and prediction analysis of China's real estate index and stock trend based on CNN-LSTM algorithm optimized by neural networks.

Today, with the rapid growth of Internet technology, the changing trend of real estate finance has brought great an impact on the progress of the social economy. In order to explore the visual identification (VI) effect of Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) algorithm based on neural network optimization on China's real estate index and stock trend, in this study, artificial neural network (ANN) algorithm is introduced to predict its trend. Firstly, LSTM algorithm can effectively solve the problem of vanishing gradient, which is suitable for dealing with the problems related to time series. Secondly, CNN, with its unique fine-grained convolution operation, has significant advantages in classification problems. Finally, combining the LSTM algorithm with the CNN algorithm, and using the Bayesian Network (BN) layer as the transition layer for further optimization, the CNN-LSTM algorithm based on neural network optimization has been constructed for the VI and prediction model of real estate index and stock trend. Through the performance verification of the model, the results reveal that the CNN-LSTM optimization algorithm has a more accurate prediction effect, the prediction accuracy is 90.55%, and the prediction time is only 52.05s. At the same time, the significance advantage of CNN-LSTM algorithm is verified by statistical method, which can provide experimental reference for intelligent VI and prediction of trend of China real estate index and property company stocks.

Design and Performance Verification of a Novel RCM Mechanism for a Minimally Invasive Surgical Robot.

Minimally invasive surgical robots have the advantages of high positioning accuracy, good stability, and flexible operation, which can effectively improve the quality of surgery and reduce the difficulty for doctors to operate. However, in order to realize the translation of the existing RCM mechanism, it is often necessary to add a mobile unit, which is often bulky and occupies most space above the patient's body, thus causing interference to the operation. In this paper, a new type of planar RCM mechanism is proposed. Based on this mechanism, a 3-DOF robotic arm is designed, which can complete the required motion for surgery without adding a mobile unit. In this paper, the geometric model of the mechanism is first introduced, and the RCM point of the mechanism is proven during the motion process. Then, based on the establishment of the geometric model of the mechanism, a kinematics analysis of the mechanism is carried out. The singularity, the Jacobian matrix, and the kinematic performance of the mechanism are analyzed, and the working space of the mechanism is verified according to the kinematic equations. Finally, a prototype of the RCM mechanism was built, and its functionality was tested using a master-slave control strategy.

Estimation of regional actual evapotranspiration based on the improved SEBAL model

The global food and water crises caused by climate warming are becoming increasingly significant. One of the important aspects of surface water transfer is evapotranspiration. The accurate estimation of evapotranspiration (ET) is of great significance in water resource management. However, accurate estimation of large-scale ET is challenging due to the adequate selection of the hot and cold pixels, the heterogeneity of the subsurface and the instability of the lower atmosphere. Therefore, in this paper, a surface energy balance model (Y-SEBAL) was proposed based on the SEBAL model and improved sensible heat flux calculation, and used to simulate large-scale actual evapotranspiration. Based on the principle of surface energy balance, this model introduced the empirical formula of sensible heat flux and simplifies the selection of limit to address the challenge of calculating the sensible heat flux of the crucial variable in the SEBAL model. The study simulated the spatial and temporal evolution of regional evapotranspiration with the model and verified the model simulation performance. In addition, the sensitivity of the model-driven data was quantified. The results showed that the simulation value of the Y-SEBAL model was highly consistent with the eddy covariance measurement data. In the verification results, the R value was 0.82, the index of agreement was 0.90, and the root mean square error was 0.81 mm·d−1. The performance verification indices were better than the SEBAL model, MOD16 model, and SSEBop model. And the model had the highest sensitivity to wind speed, reaching 0.714. The Y-SEBAL model improved the simulation performance of the original model and simulated the actual evapotranspiration. The study can provide a new solution for improving the retrieval of evapotranspiration by remote sensing at the regional scale.

Innovative Data-Driven Energy Services and Business Models in the Domestic Building Sector

The market of energy services for the residential sector in Europe is very limited at present. Various reasons can be argued such as the high transaction costs in a highly fragmented market and the low energy consumption per dwelling. The rather long payback time for investments render Energy Services Companies’ (ESCOs) services financially unattractive for many ESCOs and building residents, thus hindering a large potential of energy savings in a sector that is responsible of almost half of Europe’s energy consumption. If the ambitious 2030 and 2050’s decarbonisation targets are to be met, the EU’s residential sector must be part of the solution. This paper offers insights about novel ESCO business models based on intensive data-driven Artificial Intelligence algorithms and analytics that enable the deployment of smart energy services in the domestic sector under a Pay-for-Performance (P4P) approach. The combination of different sources of energy efficiency services and the optimal participation of domestic consumers in aggregated demand response (DR) schemes open the door to new revenue streams for energy service providers and building residents and reduce the hitherto long payback periods of ESCOs services in the sector. Innovative business models for ESCOs and demand flexibility Aggregators are thoroughly described. Especially customised Performance Measurement and Verification protocols enable fair and transparent P4P ESCO contracts. The new human-centric energy and non-energy services increase the energy consumption awareness of building users and deploy behavioural and automated responses to both environmental and market signals to maximise the economic benefit for both energy service providers and consumers, always respecting data protection rules and the consumers’ comfort preferences. The new hybrid business models of P4P energy services make traditional EPC more attractive to energy service providers, with low cost data collection and treatment systems to bring payback periods below 10 years in the residential building sector.

Modern metal framed glazed façades refurbishment: conservation in the energy and ecological transition

Metal framed glazed façades and curtain walls can be considered one of the most important innovations of modern architecture but are certainly a critical point in the conservation of modern heritage. Next to the most important modern architecture masterpieces, which are under special conservation and safeguard regulations, are a lot of minor and less known architectures that are part of the diffuse modern heritage and risk to be compromised in refurbishment interventions. In most cases, modern metal framed glazed façades systems do not meet the current energy requirements, and it is difficult to preserve them in their original features, finding a compromise between conservation and energy and ecological transition. This contribution presents a critical overview of the problems relating to the conservation of metal framed glazed façades built in the second half of the twentieth century. Requirements and standards established by energy and environmental international protocols and Italian regulations are critically analysed. Through the description of case studies, different attitudes of intervention are presented and discussed: from conservation to total replacement, with a radical change of modern building envelope original features. The mere verification of the minimum performances required by the current regulations inevitably leads to the substitution of original curtain walls. Therefore - looking beyond but respecting the regulations - architects in charge of refurbishment interventions can find innovative envelope technologies and function distribution solutions to preserve curtain walls, limiting the intervention to the strictly needed.

Two-stage ANN based intelligent technique for optimal positioning and sizing of DERs in distribution system

Recent years have examined large transformational implications due to integration of highly intermittent renewable sources of energy. Therefore, initiatives must be explored to enhance the operational flexibility of distributed energy resources (DER) for bringing a new viewpoint to the planning and operation of future distribution system. Also, despite the economic, environmental and societal advantages of DERs, their adoption is limited and markets are yet to realize its full potential to address the operational challenges of the system. The solution to these is integration of multiple DERs in the system of appropriate size at optimal location in the system. Currently, numerous optimization methods based on rigorous mathematical calculation are used to solve this issue. This inevitably increases the complexity of such algorithms. Therefore, this paper proposes a two-stage artificial neural network (ANN) based intelligent technique to solve the problem. In this work, first stage ANN is used for screening the critical buses rank wise based on voltage, line and power stability index to find the optimal location. In second stage ANN, screening the size of DER based on the location of critical bus is accomplished to find the optimal sizing of DER. The intelligent technique proposed in this work is applicable to both radial as well as networked system. The solution is extensively evaluated through simulation in MATLab for a set of operational scenarios and performance verification of the proposed technique is provided for IEEE 33 and 69 bus systems for radial and IEEE 14 and 118 bus systems for mesh networked systems. The results validate the efficacy of the proposed technique.

ON THE USE OF SOUND SPEED FOR EVALUATION OF THE PERFORMANCE OF LIQUID ULTRASONIC FLOW METER IN ZERO FLOW CONDITIONS

At present, ultrasonic flow meters have become well known in custody transfer applications in the petroleum industry. Since facilities for calibration of these meters are costly and limited, methods for performance verification in zero flow conditions have been developed. However, for liquid measurement, a method of zero flow verification is not available yet. In this context, this study presents a new method for zero flow test in liquid ultrasonic flow meters, using a highly accurate instrument as a reference for sound speed. The aim is to evaluate the performance, of a multipath liquid ultrasonic flow meter under different pressures and temperatures, by comparing the calculated sound speed with the result from the reference instrument. Additionally, transit time measurement is also verified in order to account for systematic errors. The experiments were conducted with two test fluids: water and mineral oil, with a maximum deviation of 0.25% during comparison. On the other hand, performing a transit time analysis indicates the presence of systematic errors, meaning that transit times can be adjusted in order to improve the performance of the flow meter. Furthermore, a factorial design is performed to investigate the effect of pressure and temperature, indicating a minimal pressure effect on sound speed when compared to the temperature effect.

Acoustical privacy in the built environment: Past, present and future

Although the need to consider acoustics in the built environment is well-accepted, an understanding of 'what' constitutes 'good acoustics' is not. The authors present posteriori-reviews of historical events and of empirical evidence-to develop an understanding of the current landscape of Standards, Guidelines, and Codes. More specifically, special attention is devoted to the development of speech privacy metrics, as well as that of auditory and non-auditory effects of noise and sound on health. With a refreshed understanding of theory, a priori-i.e., an acoustical framework for design and/or performance verification with a special interest in speech privacy-is renewed and its impacts on the ongoing development of Standards, Guidelines and Codes is discussed.

A simplified analytical approach for assessing non-linear in plane seismic response of stick-built glass curtain walls

In the last decades, glass facades are increasingly used for building skin, especially for their pleasant aesthetic look. During recent earthquakes, such systems have often shown significant damages. Sometimes this made the whole building inoperable, even in the case of no structural damage, so causing extensive direct and indirect losses (e.g. due to the downtime). Herein, the author starts from the experience they gained performing laboratory tests and non-linear finite-element models of stick-built glazing systems to give a contribution in the direction of a simplified modeling of the seismic behavior for such components. An approximate analytical method is herein proposed for an expeditious estimate of the non-linear seismic capacity of a glass-aluminum façade system. This tool can be of great use to the professional dealing with the design and preliminary verification of the seismic performance of such a façade, avoiding or, at least, limiting the use of demanding laboratory tests. Some suggestions are also given about its possible use in the framework of code-based applications. Input data are geometry and mechanical parameters of involved materials. The output is a non-linear static pushover curve representing the lateral response of the façade. The step-by-step procedure is first introduced and explained in terms of assumptions and methodological approach, then applied to a commercial case-study façade, previously tested through a 1:1 sample at the ITC-CNR laboratory (Milan, Italy). The simplified model provides a very fine match to the experimental data, so demonstrating its effectiveness.

Tempestuous life beyond R500: X-ray view on the Coma cluster with SRG/eROSITA

This is the second paper in a series of studies of the Coma cluster using the SRG/eROSITA X-ray data obtained during the calibration and performance verification phase of the mission. Here, we focus on the region adjacent to the radio source 1253+275 (radio relic, RR, hereafter). We show that the X-ray surface brightness exhibits its steepest gradient at ∼79′ (∼2.2 Mpc ≈ R200c), which is almost co-spatial to the outer edge of the RR. As in the case of several other relics, the Mach number of the shock derived from the X-ray surface brightness profile (MX ≈ 1.9) appears to be lower than needed to explain the slope of the integrated radio spectrum in the diffusive shock acceleration model (MR ≈ 3.5) if the magnetic field is uniform and the radiative losses are fast. However, the shock geometry is plausibly much more complicated than a spherical wedge centered on the cluster, given the non-trivial correlation between radio, X-ray, and SZ images. While the complicated shock geometry alone might cause a negative bias in MX, we speculate on a few other possibilities that may affect the MX − MR relation, including the shock substructure that might be modified by the presence of non-thermal filaments stretching across the shock and the propagation of relativistic electrons along the non-thermal filaments with a strong magnetic field. We also discuss the “history” of the radio galaxy NGC 4789, which is located ahead of the relic in the context of the Coma-NGC 4839 merger scenario.

Energy-Efficient UAV-Based IoT Communications With WiFi Suppression in 5 GHz ISM Bands

Unmanned Aerial Vehicle (UAV) based communication is a promising technology for offering wireless communication services. UAVs can typically be adopted as aerial base stations to collect data from ground Internet of Things (IoT) devices. However, the Ground-to-Air link of UAV-based IoT communications is prone to be interfered by surrounding WiFi devices in the Industrial, Scientific, Medical (ISM) band. This paper aims to enable reliable uplink communications for IoT devices in 5 GHz ISM bands, thereby reducing the hover time and energy consumption of the UAV. To this end, we first study and design suppression frames suitable for WiFi devices. Then a suppression method is proposed, which is shown to be effective for all the tested devices, based on emulation performance verification of the frames for multiple commercial off-the-shelf (COTS) WiFi devices. Moreover, by taking the energy consumption of the UAV and multiple transmission parameters of the suppression method into account, we formulate an optimization problem for the desired uplink, which is designed to minimize the energy consumption of the UAV, under the constraints of satisfying the link channel capacity. Given that the optimization problem is non-convex mixed-integer nonlinear programming, this paper proposes an efficient algorithm that takes advantage of the suppression performance of the utilized frames. Numerical simulations demonstrate the performance of the proposed algorithm in terms of the WiFi device density, UAV weight, channel capacity requirement and parameters of the suppression method. The communication quality of the desired Ground-to-Air link is shown to be significantly improved, while the consumed energy is demonstrated to be obviously reduced.

<b>Performance Verification of Design Method for Plain Concrete Linings and Inverts Assuming Ground Displacement after Completion</b>

There are various structures in railway systems. These structures including tunnels need to have the same level of performance and their performance should be verified quantitatively. Therefore, we proposed a method for verifying the performance of plain concrete linings and inverts, and developed a trial design assuming a mountain tunnel receiving ground deformation after completion. In the trial design, we imposed the displacement to the lining and invert using a ground deterioration model. As a result, it was found that the performance can be verified using the proposed method, and that the required performance can be satisfied by adopting strong invert structures against floor heave.

Opportunism in supply chains: Dynamically building governance mechanisms to address sustainability-related challenges

Opportunism has long been highlighted as one of the hazards of complex buyer–supplier relationships. This hazard has become more challenging to manage as the pressure from consumers and the public for improved sustainability-related performance is passed along the supply chain between buyers and suppliers. For example, buyer demands for and supplier implementation of sustainability requirements, such as low carbon emissions or fair worker treatment, are often poorly defined; difficult to document; and subject to change as pressure for immediate improvement builds, as scientific understanding deepens and as societal expectations advance. This complex setting generates tempting openings for either a buyer or supplier to act opportunistically. In an effort to advance both theory and managerial practice, we consider three aspects of sustainability-related opportunism. First, in line with prior research, we focus on defining sustainability-related opportunism as jointly considering the codification of expectations and verification of performance (while allowing for false suspicions). Second, our conceptualization stresses the need to move away from an implied static view to embrace more fully the changing nature of stakeholders’ sustainability-related concerns. For example, supply chain relationships evolve based on repeated interactions as firms influence each other’s beliefs, practices and outcomes. Third, in a related sense, a dynamic model can combine several theoretical perspectives to inform how the balance of transactional and relational governance mechanisms might adapt as our understanding of sustainability changes, institutional forces evolve, and dyadic relationships mature.

A MOOC-Based Hybrid Teaching Model of College English

In the era of intelligence, Internet + technology is widely used in various fields, and English Teaching in the education industry of colleges and universities gradually tends to be an online and offline mixed teaching mode. However, under the MOOC model, the feedback of College Students’ English learning and the recognition of their knowledge level has become new difficulties. Aiming at the feedback of students’ learning situation under the mixed mode of College English teaching, this paper uses the optimized Bayesian knowledge tracking model (BKTM) to predict students’ English learning situation and introduces students’ learning behavior and forgetting behavior to optimize parameters. Finally, a performance verification experiment is carried out by analyzing the students’ answer performance in College English mixed teaching. The results show that the prediction errors of the four knowledge points of 60 students in the two classes are all about 7%, and the maximum error is 11%. Experiments show that the model has high accuracy and stable performance in predicting the probability of mastering knowledge points.

Experimental performance verification of radial and axial flux line start permanent magnet synchronous motors

Experimental performance verification of radial and axial flux line start permanent magnet synchronous motors

Evaluation of Power Performance of Solar Module Using Two Diode Model with MATLAB Simulation

This paper tries to represent the difference between single diode and two diode photovoltaic models in terms of efficiency simulated by MATLAB. The research activities done earlier had shown a clear preview that the solar cell can act as concentrated solar cell for increasing the conversion efficiency to a great extant so that output power can be improved to a large scale. Here for showing the manner of concentrated solar action double diode model has been calculated for observing the power difference in comparison with the solar cell of single diode as a convenient one. It has been observed that the photovoltaic module with two diode model is observed as highly efficient in comparison with single diode model. And this two diode model can be treated as highly efficient to convert the solar energy in the electric energy. Also, the behavior of power performance is observed practically which is included in this paper. And finally, a comparison has been drawn out to exhibit the verification of power performance for two diode model using MATLAB simulation. The mostly impact factors considered in this paper are solar irradiance and temperature affecting the power output from PV module.