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This paper discusses the challenges in accurately measuring the far-field performance of array antennas, which have become more complex and larger due to recent trends in increasing the number of elements and the antenna size. The far-field measurement method, which is a general method for measuring a radiation pattern in a far-field, is difficult to be utilized at a high frequency due to limitations in physical chamber size and difficulty in diagnosing an antenna. In order to improve these problems, a near-field measurement method is used as an alternative. Even though using a near-field measurement, the accuracy of the derived far-field pattern is reduced at low elevation angles due to zero-padding of data outside the measurement area. The integration of the near-field measurement with the source reconstruction is a promising approach to enhance the measurement limits of the far-field pattern analysis. This paper aims to extend the previous work to accurately predict the far-field radiation pattern, especially in the low elevation angles. The verification of the proposed method is performed for a standard gain horn and 4 by 4 patch array antennas, with and without beam steering. [ABSTRACT FROM AUTHOR]

This paper focuses on the characterization of radio propagation, and data communication in a marine environment. More specifically, we consider signal propagation when three different sub-gigahertz industrial, scientific, and medical (ISM) bands, i.e., 169 MHz, 434 MHz, and 868 MHz, are used. The main focus of the paper is to evaluate the path loss (PL), i.e., the power loss that a propagation radio wave would experience when communication occurs between a sail boat and a buoy. We describe the measurement results obtained performing three different radio power measurement campaigns, at the three different aforementioned ISM sub-gigahertz bands. We also want to correlate the radio propagation quality with the weather conditions present in the measurement areas. The obtained results show that higher distances are achieved by transmitting at lower frequencies, i.e., 169 MHz, and, on average, the propagation is directly dependent from the dew point index. [ABSTRACT FROM AUTHOR]

Imaging disdrometers are widely used in field campaigns to provide information on the shape of hydrometeors, together with the diameter and the fall velocity, which can be used to derive information on the shape–size relations of hydrometeors. However, due to their higher price compared to laser disdrometers, their use is limited to scientific research purposes. The 3D stereo (3DS) is a commercial imaging disdrometer recently made available by Thies Clima and on which there are currently no scientific studies in the literature. The most innovative feature of the 3DS is its ability in capturing images of the particles passing through the measurement volume, crucial to provide an accurate classification of hydrometeors based on information about their shape, especially in the case of solid precipitation. In this paper. the performance of the new device is analyzed by comparing 3DS with the Laser Precipitation Monitor (LPM) from the same manufacturer, which is a known laser disdrometer used in many research works. The data used in this paper were obtained from measurements of the two instruments carried out at the Casale Calore site in L'Aquila during the CORE-LAQ (Combined Observations of Radar Experiments in L'Aquila) campaign. The objective of the comparison analysis is to analyze the differences between the two disdrometers in terms of hydrometeor classification, number and falling speed of particles, precipitation intensity, and total cumulative precipitation on an event basis. As regards the classification of precipitation, the two instruments are in excellent agreement in identifying rain and snow; greater differences are observed in the case of particles in mixed phase (rain and snow) or frozen phase (hail). Due to the different measurement area of the two disdrometers, the 3DS generally detects more particles than the LPM. The performance differences also depend on the size of the hydrometeors and are more significant in the case of small particles, i.e., D < 1 mm. In the case of rain events, the two instruments are in agreement with respect to the terminal velocity in still air predicted by the Gunn and Kinzer model for drops with a diameter of less than 3 mm, while, for larger particles, terminal velocity is underestimated by both the disdrometers. The agreement between the two instruments in terms of total cumulative precipitation per event is very good. Regarding the 3DS ability to capture images of hydrometeors, the raw data provide, each minute, from one to four images of single particles and information on their size and type. Their number and coarse resolution make them suitable to support only qualitative analysis of the shape of precipitating particles. [ABSTRACT FROM AUTHOR]

The designed MYRRHA reactor, in its subcritical version, will be equipped with a set of detectors monitoring its condition by measuring the current value of negative reactivity, which is a crucial parameter for its safe operation. In subcritical systems, accurate and precise measurement of negative reactivity is disturbed by the so-called spatial effect, i.e., the response of detectors depends on their placement in the reactor core. This paper focuses on the Monte Carlo simulations of reactivity measurements using the area method for natU, 238U, 241Am, 239Pu, and 232Th detectors. The simulations were performed in six positions with increasing distance from the center of the core and at three axial levels. The obtained results allow for selecting optimum locations for detectors and detector nuclides in terms of the accuracy of reactivity measurement and illustrate the dependence of the reactivity on the distance. Additionally, the possibility of using 103Rh in self-powered neutron detectors was investigated. The influence of spatial effect in calculations using the area method was directly indicated in the MYRRHA reactor core for chosen isotopes and in-core positions. The results closest to true values were obtained for the second fuel assembly for 239Pu, and the third fuel assembly for natU, 238U, 232Th, and 241Am; thus, these nuclides and positions should be preferred when selecting detectors for MYRRHA. [ABSTRACT FROM AUTHOR]

For users of Precise Point Positioning (PPP), Multi-GNSS Advanced Orbit and Clock Augmentation PPP signals provide corrective data. When using the PPP approach and/or PPP-Ambiguity Resolution (AR) method, the QZSS signal provides globally applicable error corrections on satellite orbit, clock offset, and code/phase biases. In addition, from FY2024, as a part of the MADOCA-PPP technology demonstration, wide-area ionospheric correction data will be provided for the Asia-Oceania region. A software estimator of precise satellite information developed by JAXA, Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA), allows u-blox CO99-ZED-F9P and MSJ 3008-GM4-QZS utilizing MADOCA-PPP to be used in GNSS applications that need sub-decimetre precision but don't have to be expensive. Errors caused by positioning satellites are computed by using observation data from domestic and overseas GNSS monitoring station networks such as IGS and MIRAI, and obtained correction data is transmitted from QZSS signal to provide highly precise positioning augmentation services that can be used in the Asia-Oceania Region. Users may utilize the PPP technique for high-precision locating by employing a GNSS receiver that supports the QZSS signals. This paper describes an experiment carried out with the static method to combine GPS, GLONASS, and QZSS signals in the project site (ISHI, USUD and MIZU stations in Japan). This paper examines the GPS/GLONASS/QZSS obtainable accuracy. These obtained results indicate that integrating GPS system with GLONASS and QZSS is favoured for surveying applications. It appears that integrating GPS/GLONASS/QZSS (MADOCA precise ephemeris file) static measurements in the study area between 0-4 millimetres accuracy can be guaranteed on all occasions. [ABSTRACT FROM AUTHOR]

The ecological footprint basically aims to measure the impact of humans on the ecosystem. The measurements include the area required to produce the materials consumed in terms of the consumption footprint and the area required to absorb the carbon dioxide emissions. No distinction is made between domestic and foreign producers in the production by the countries. The countries with the most developed industry and the highest impact on the ecosystem in this sense appear as the countries with the highest footprint in the ecosystem. This study, based on the ecological footprint data of seven industrialized countries (G7) between 1984 and 2019, aims to reveal the effect of ecological footprints on trade openness. Panel data analysis and ARDL Boundary Test / PMG method was used to obtain the results. DOLS and FMOLS methods were also used to compare both economic and empirical results and for consistency. As a result of the analysis, as the impact of industrialized countries on the ecosystem increases, their trade openness also increases in the short and long term. This effect could be seen most clearly in the United States (USA), which has the most developed industry. This research paper points out these important issues. [ABSTRACT FROM AUTHOR]

Compared with aeromagnetic total-field data, aeromagnetic vertical gradient field data contain less low-frequency information. In this paper, a continuation conversion filtering algorithm is proposed to filter out part of the low-frequency information of the aeromagnetic total-field data so that these data can be better compared with the total-field data obtained from aeromagnetic gradient data conversion. We discuss the feasibility of single aeromagnetic vertical gradient measurement in areas where it is inconvenient to erect base stations. We design a simple model and a complex model with a background field and random noise to analyze the conversion effect. The model analysis shows that the effect of applying the algorithm depends heavily on the selection of upward continuation height. The magnetization intensity of the background field also affects the selection of continuation height. When the magnetization intensity of the background field is weak, the continuation height chosen is the same as the buried depth of the background field. If the magnetization intensity of the background field is strong, then the higher the continuation height, the better the effect will be. The conclusion of the model analysis is applied to the analysis of the measured aeromagnetic data. In addition, we can conclude that the effect on total-field data of conversion by the continuation conversion filtering algorithm is better than that of conversion from the aeromagnetic vertical gradient data. [ABSTRACT FROM AUTHOR]

The recent surge of machine learning (ML) has impacted many disciplines, including educational and psychological measurement (hereafter shortened as measurement). The measurement literature has seen rapid growth in applications of ML to solve measurement problems. However, as we emphasize in this article, it is imperative to critically examine the potential risks associated with involving ML in measurement. The MxML project aims to explore the relationship between measurement and ML, so as to identify and address the risks and better harness the power of ML to serve measurement missions. This paper describes the first study of the MxML project, in which we summarize the state of the field of applications, extensions, and discussions about ML in measurement contexts with a systematic review of the recent 10 years' literature. We provide a snapshot of the literature in (1) areas of measurement where ML is discussed, (2) types of articles (e.g., applications, conceptual, etc.), (3) ML methods discussed, and (4) potential risks associated with involving ML in measurement, which result from the differences between what measurement tasks need versus what ML techniques can provide. [ABSTRACT FROM AUTHOR]

The study of the area of circles is an important component of mathematics education for students of all ages; however, evidence suggests that many middle school students struggle to interpret and apply the area formula of a circle. In this article, I report the findings of a classroom design study conducted to investigate the collective establishment and justification for the area formula of a circle. An instructional sequence comprising paper-based decomposition and recomposition measurement tasks situated on a grid was implemented in a Year 8 classroom (n = 18) and the collective mathematical practices that emerged from an analysis of the argumentation of students during whole-class discussion were documented. The findings extend the existing literature by illustrating how decomposition/recomposition tasks can be leveraged in a classroom context by grounding students’ reasoning in measurement strategies and opportunities to examine alternative strategies and justifications through whole-class discussions. [ABSTRACT FROM AUTHOR]

• A search-vector imaging condition is proposed based on waveform inversion. • The imaging condition makes no assumption about the wavefield and is more rigorous. • The proposed method highlights the defects in the measurement area with high accuracy. • The proposed method greatly improves the imaging accuracy, resolution and SNR. • The proposed method is strongly robust and not sensitive to various factors. Complex-surface components play more and more significant roles in engineering practice because of the development of manufacturing technology and requirements from various industries. Void and crack defects inside the components greatly deteriorate the mechanical properties, and ultrasonic full-matrix imaging is a promising method to detect the defects. However, the research on high-quality full-matrix imaging for complex-surface components is limited. In this paper, a full-matrix imaging method based on the search-vector imaging condition is proposed to detect the defects in complex-surface components with high accuracy. Herein, the search-vector imaging condition is established based on waveform inversion, which employs the first-order derivative vector and approximated Hessian matrix to obtain the high-accuracy images of defects. The proposed imaging condition does not make assumptions about the wavefield and is more rigorous than the conventional excitation-time imaging condition. Furthermore, the proposed method can highlight defects throughout the measurement area, so it is very convenient for locating defects in large measurement structures. In the simulation and experiments, defects in complex sound speed models are the measurement targets, and the proposed method has significantly improved the imaging accuracy, resolution and signal-to-noise ratio (SNR) in all cases compared with the conventional methods, where all the void and crack defects are highlighted clearly in the whole image. In addition, the proposed method is not sensitive to the influencing factors and has strong robustness. Therefore, the proposed method has great potential in defect detection for complex-surface components in various fields. [ABSTRACT FROM AUTHOR]

Enhancing the silicon surface smoothness with chemical mechanical polishing (CMP) is crucial to achieve better beam quality in X-ray systems. The additive in CMP slurry is the key factor in determining the resulting surface morphology. This paper exploits the effect of isopropanol (IPA) additive on regulating the material removal process and resulting microscopical surface morphology through varying the IPA concentration and polishing pressure. The improvement of surface quality and a dropping material removal rate (MRR) are obtained by increasing the IPA concentration from 0.1 to 2.5 mol/L. When the polishing pressure increases from 0.25 to 0.48 psi, a better surface quality and enhanced MRR are observed. By using the optimal polishing pressure of 0.48 psi and IPA concentration of 2.5 mol/L, the root-mean-square roughness can be reduced to 0.10 nm under a measurement area of 1 µm × 1 µm with atomic force microscopy, more than 58.3% lower compared to surfaces polished without IPA. This work suggests an approach to obtain the ultra-smooth silicon mirrors, which has promising applications in the field of X-ray, aerospace, and photovoltaics. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper investigated the removal mechanism and surface quality of single crystal 4 H-SiC during the grinding process, as well as the impact of the measurement area on surface roughness (S a) during surface morphology detection. This problem is relatively unexplored. Experimental findings suggest that when the measurement area is below 400 µm², there is a greater error in S a. Conversely, when the measurement area exceeds 400 µm², the error in S a values is relatively small and stable. The surface quality increases with the increase of wheel speed (v s) and decreases with the increase of workpiece feed rate (v w) and grinding depth (a p). This study finds that the material removal of monocrystalline single crystal 4 H-SiC during the grinding process occurs primarily through plastic deformation, accompanied by brittle fracture. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, promoting regional synergistic development has become the shared objective in city-regions during the new stages of development. This paper aims to uncover the dynamics of synergistic development in urban agglomerations by constructing an index measurement system based on four dimensions: industrial synergy, innovation synergy, infrastructure synergy, and institutional synergy. By comprehensively employing theories and methods such as "space of flow" big data analysis, network analysis, and interlocking network models, this study examines patterns and capacities of synergistic development in the Guangdong-Hong Kong-Macao Greater Bay Area. The main instances of industrial cooperation between cities are observed in Hong Kong-Shenzhen and Guangzhou-Shenzhen; capital flows primarily concentrate in Guangzhou-Shenzhen and Hong Kong-Shenzhen. Research paper and patent collaborations between cities are predominantly concentrated in Hong Kong-Shenzhen; joint laboratories are mainly established in Hong Kong-Macao and Hong Kong-Guangzhou; inter-city co-construction of higher education institutions is mainly focused on Guangzhou-Foshan and Shenzhen-Hong Kong. Infrastructure synergistic development performs best in Guangzhou-Shenzhen, Guangzhou-Foshan, and Shenzhen-Dongguan. Cross-border collaboration benefits from institutional advantages held by Hong Kong and Macao. Urban interactions with outstanding performance include Guangzhou-Shenzhen, Hong Kong-Shenzhen, Guangzhou-Foshan, Shenzhen-Dongguan. Additionally, increasing interaction trends can be observed between Guangzhou-Dongguan as well as Shenzhen-Zhuhai/Shenzen-Foshan partnerships. Understanding the typical characteristics and potential trends of synergetic development within the GBA holds significant practical value for establishing a first-class bay area along with a world-class urban agglomeration. • Concept and connotation of synergistic development in urban agglomeration area was examined. • Indicators and methods for evaluation of synergistic development in the GBA were conducted. • Patterns and capacities of synergistic development at urban scale in the GBA were explained. • Urban interaction with highest synergistic development level is Guangzhou-Shenzhen. [ABSTRACT FROM AUTHOR]

• The slow convergence rate and lack of positive semi-definiteness issues of UKF are surmounted. • Whale Optimization Algorithm (WOA) and Tunicate Swarm Algorithm (TSA) are used to develop HW-TO-UKF. • The proposed HW-TO-UKF is used to optimize scaling parameters that are involved in computing the weights of the sigma points of UKF. • WSCC-3 machine and NPCC_48 machine systems are used for simulations. • The efficacy of proposed HW-TO-UKF is compared with various heuristic-based existing methods. The Energy Management Systems (EMS) utilizes Dynamic State Estimation to monitor the operating condition of the power grid. For a synchronous generator, the speed and angle of a rotor are the most important dynamic states. These states are responsible for producing uncertainty in the power system models. Extended Kalman Filter (EKF) and Unscented Kalman Filters (UKF) are utilized to estimate the dynamic states of the power system when it perceives significant disturbances or noise. The conventional Unscented Kalman Filter (UKF) has limitations in terms of slow convergence speed and its lack of positive semi-definiteness. This prohibits its ability to accurately track the transients of the system. The scaling parameters of UKF (alpha and beta) are optimally tuned to overcome these issues. In this paper, a novel Hybrid Whale-Tunicate-based UKF (HW-TO-UKF) is proposed for tuning the scaling parameters of UKF for reducing the mean difference between the real state and the measured state. During the validation of the proposed method, better robustness and statistical efficiency are achieved by defining the objective function as the minimization of the error difference between the actual and measured states. The simulation is carried out on the WSCC-3 and NPCC-48 machine systems to demonstrate the performance of the proposed HW-TO-UKF over the existing models. [ABSTRACT FROM AUTHOR]

The increasing integration of renewable energy resources in active distribution networks (ADNs) aggravates voltage deviations. Fluctuations among distributed generators (DGs) and the absence of accurate network parameters hinder the performance of model-based voltage control method. How to utilize the advantages of measurement-based data-driven method combined with model-based method has become the key to effectively addressing voltage issues. This paper proposes a data-model hybrid-driven adaptive voltage control method for ADNs. A data-model hybrid-driven adaptive voltage control framework containing two hybrid modes is established with the consideration of measurement configuration. In the data-model correction mode, the performance of data-driven control is improved by prior physical knowledge in adequate measurement area. In the data-model coordination mode, the inter-area coordination realizes the complementarity of the regulating ability between the areas with adequate measurement and those without. Finally, analysis and verification are performed based on the modified IEEE 33-node distribution network. The results demonstrate that the proposed hybrid-driven voltage control method has superiority in adaptability to DG fluctuations and strategy interpretability, which obtains satisfied voltage control performance. • Data-model hybrid-driven adaptive control framework for ADNs was established. • Data-model correction mode was proposed to improve data-driven performance. • Data-model coordination mode was proposed to cope with uneven measurements. [ABSTRACT FROM AUTHOR]

• The identification of boundary tractions with limited measurements is achieved. • The impact of measurement area and location on the accuracy is thoroughly studied. • The relative error is below 4% using the experimental data of only 3 points. Traction distribution is often unknown in solid mechanics. However, identifying traction distribution with both high accuracy and spatial resolution can sometimes be critical. In this paper, we consider the frequent situation where incomplete deformation measurements, such as partial surface measurements obtained by digital image correlation, are available. For such situations, we propose to achieve the complete identification of boundary tractions, using an optimization based inverse method. The feasibility and robustness of the proposed approach are firstly assessed with numerical simulations. We show that complete traction distributions can be identified with high accuracy even when there is noise added to the deformation measurements. More specifically, the relative error was less than 3% even with 10% noise. Moreover, the effect of noise depends significantly on the level of incompleteness of the deformation data. We show for instance that when the measurement area is 8.3% of the solid, the relative error can be 5 times larger than when the measurement area is 33.3%. However, even with 8.3% deformation measurement area of the solid, the relative error of the mapped traction distribution can be less than 6%. Besides, the accuracy of the mapped traction distribution can be further improved if the region of the deformation measurement is closer to the traction boundary. We eventually validate the proposed inverse approach using incomplete experimental datasets consisting in tensile tests carried out on two elastic samples. We obtain very promising results, with relative errors below 4% using the measured displacements of only 3 points, which is promising to open potential applications in different fields of engineering. [ABSTRACT FROM AUTHOR]

• A comprehensive review of system frequency dynamic behaviors monitoring techniques based on measurements is provided. • The applications of wide area measurements in system frequency security assessment modeling methods are summarized. • New insights for future works on frequency issues and potential solutions with the applications of measurements are extensively discussed. The massive integration of clean energy and renewable energy source (RES) is one of the most important trends in the low carbon energy transition toward carbon neutrality. Such an important goal significantly alters the power system dynamic behavior. Consequently, monitoring and analyzing the complex frequency dynamic of RES-dominated power systems play an essential role in ensuring power system security and stability. The measurements, especially those supported by wide area measurement systems (WAMSs), can enable full state awareness and deep informatization of the power system and therefore provide effective solutions for monitoring and analyzing system frequency dynamic behaviors with complex features. This paper focus on the application of measurements in monitoring and modeling analysis technologies for the features of frequency dynamics of RES-dominated power systems. We summarize related research on online monitoring of frequency dynamic behavior features based on the information from measurements. Further, for system frequency security assessment, measurements can improve the traditional methods and promote new data-driven methods for more accuracy and effective frequency dynamics analysis. Finally, future directions and possible solutions for measurement-based frequency dynamics monitoring and analyzing are prospected. [ABSTRACT FROM AUTHOR]