Power Measurements Research Articles

Intelligent Reflecting Surfaces for Visible Light Positioning Based on Received Power Measurements

Intelligent Reflecting Surfaces for Visible Light Positioning Based on Received Power Measurements

Spatiotemporal landscape pattern changes and their effects on land surface temperature in greenbelt with semi-arid climate: A case study of the Erbil City, Iraq

Urban expansion of cities has caused changes in land use and land cover (LULC) in addition to transformations in the spatial characteristics of landscape structure. These alterations have generated heat islands and rise of land surface temperature (LST), which consequently have caused a variety of environmental issues and threated the sustainable development of urban areas. Greenbelts are employed as an urban planning containment policy to regulate urban expansion, safeguard natural open spaces, and serve adaptation and mitigation functions. And they are regarded as a powerful measure for enhancing urban environmental sustainability. Despite the fact that, the relation between landscape structure change and variation of LST has been examined thoroughly in many studies, but there is a limitation concerning this relation in semi-arid climate and in greenbelts as well, with the lacking of comprehensive research combing both aspects. Accordingly, this study investigated the spatiotemporal changes of landscape pattern of LULC and their relationship with variation of LST within an inner greenbelt in the semi-arid Erbil City of northern Iraq. The study utilized remote sensing data to retrieve LST, classified LULC, and calculated landscape metrics for analyzing spatial changes during the study period. The results indicated that both composition and configuration of LULC had an impact on the variation of LST in the study area. The Pearson’s correlation showed the significant effect of Vegetation 1 type (VH), cultivated land (CU), and bare soil (BS) on LST, as increase of LST was related to the decrease of VH and the increases of CU and BS, while, neither Vegetation 2 type (VL) nor built-up (BU) had any effects. Additionally, the spatial distribution of LULC also exhibited significant effects on LST, as LST was strongly correlated with landscape indices for VH, CU, and BS. However, for BU, only aggregation index metric affected LST, while none of VL metrics had a relation. The study provides insights for landscape planners and policymakers to not only develop more green spaces in greenbelt but also optimize the spatial landscape patterns to reduce the influence of LST on the urban environment, and further promote sustainable development and enhance well-being in the cities with semi-arid climate.

The data recovery strategy on machine learning against false data injection attacks in power cyber physical systems

During the transmission of power measurement data through communication networks from remote terminal unit (RTU) to the state estimator in Supervisory Control and Data Acquisition (SCADA), power cyber-physical systems (PCPSs) are more susceptible to cyber-attacks. To mitigate that threat, this paper is concerned with a new data recovery strategy on machine learning against false data injection attacks (FDIAs) in PCPSs. Firstly, in view of the limited resources (such as limited energy) of adversaries and system protections, a sparse target false data injection attack (FDIA) is constructed. Then, the FDIA detection problem is transformed into a tripartite separation problem, and the alternating direction method of multipliers on proximal exchange (ADMM-PE) is adopted to complete the intrusion detection of FDIAs. In addition, with the help of reliable mask information and real incomplete measurement data provided by the FDIA detection, a similar supervised generative adversarial imputation networks (GAIN) is proposed to complete the measurement data recovery after FDIAs. Specifically, the pseudo labels generated by data analysis methods such as k-means clustering and support vector machine (SVM) to improve the accuracy of measurement data recovery. Finally, the experimental results of PCPSs show the effectiveness and superiority of the proposed data recovery strategy against FDIAs.

Goodness-of-fit tests based on Kullback-Leibler divergence for bladder cancer survival analysis: Applications to exponentiated exponential distribution

Bladder cancer is among the ten most common types of cancer worldwide, with approximately 550,000 new cases occurring each year. It accounts for comprehensively compared to 3% of all newly diagnosed cancer cases and contributes to 2.1% of cancer-related deaths globally. This article introduces goodness-of-fit tests that aim to fit the exponentialized exponential distribution. These tests are based on the Kullback-Leibler difference and have been applied to censored and complete samples of Bladder Cancer Patients. We calculated critical values and statistical power measurements, considering the best and worst bandwidth scenarios. We then comprehensively compared essential values and power across various parameters, accounting for optimal and suboptimal bandwidth choices derived from the Kullback–Leibler difference. In the final phase of our study, we used a dataset of individuals diagnosed with bladder cancer to demonstrate the practical applicability of our proposed research. Finally, this modeling type can benefit researchers and healthcare professionals through time-to-event analysis (survival analysis), investigation of events, medical decision-making, and risk prediction.

Uncertainty Calculation as a Service: Integrating Cloud-Based Microservices for Enhanced Calibration and DCC Generation.

The calibration industry is renowned for its diverse and sophisticated equipment and complex processes, which necessitate innovative solutions to keep pace with rapidly advancing technology. This paper introduces an enhancement to an existing microservice-based cloud architecture, aimed at effectively managing the inherent complexity within this field. The enhanced architecture seamlessly integrates various equipment types and communication technologies, aligning diverse stakeholder expectations into a unified system that ensures efficient and accurate calibration processes. It highlights the integration of microservices to facilitate various methods of uncertainty calculation and the generation of digital calibration certificates (DCCs). A case study on RF power measurement illustrates the practical application and benefits of the enhanced architecture. Although initially focused on RF power measurement, the flexible architecture allows for future expansions to accommodate new standards and measurement techniques. The enhanced system offers a comprehensive approach to managing data flow from calibration equipment to the final generation of DCCs, utilizing cloud-based services for efficient data processing. As a future direction, this extension sets the groundwork for broader applicability across multiple measurement types, ensuring readiness for upcoming advancements in metrology.

A comparative study between the two vertical jump tests of stability and the platform jumping device in measuring the explosive power of the two legs in female volleyball players

The research aims to: - To identify the differences between the two tests of the vertical jump of stability and the platform of the jumping platform in measuring the explosive power of the two legs of the female volleyball players. - Identifying the relationship between the two vertical jump tests of stability and the platform jumping device in measuring the explosive power of the two legs in female volleyball players. As for the research hypothesis:- -There are statistically significant differences between the standing vertical jump tests and the jumping platform device in measuring the explosive power of the legs in female volleyball players. - There is a significant correlation between the two standing vertical jump tests and the jumping platform device in measuring the explosive strength of the legs in female volleyball players. The research community was determined by the intentional method of the players of the first degree of volleyball in the Kurdistan Region / Iraq.The research sample was determined by the random method from the research community, which consisted of players from these clubs (Hajiaoa, Rania, and Tactac,koya University Team) which in total were 37 players, One female player was excluded from the Hajiao Club due to not attending the test day, and (6) female players from the Koya University team were excluded because of their participation in the reconnaissance experiment. Thus, the size of the final sample reached 30 players out of 30 players, with a rate of 81.01%. The researchers used the descriptive approach in a comparative study method. And the correlations, and after obtaining the results, they were discussed in a scientific manner supported by the sources to achieve the research goals. In light of the research results, the researchers reached the following Conclusions: - There is a correlation between the springboard mat test and the standing vertical jump test in their measurement of the explosive strength of the legs in female volleyball players. - There are differences between the springboard mat test and the vertical stability jump test in their measurement of the explosive power of the legs in female volleyball players, and in favor of the springboard mat test.

The balance of sea power in the early modern era: The Anglo-Dutch Wars (1652–1674)

The balance of power is among the foundational principles in international relations. This principle, however, has been analysed mostly in relation to land powers on the European continent, while the historiography has failed to appropriately recognize its naval aspect so far. This article compares the English and Dutch sea powers or fleets during the three Anglo-Dutch Wars (1652–1674). Warships or ships of the line were the main instruments of naval warfare, and hence key to any measurements of sea power. Detailed tables of the fleets with the number of warships and guns for the major engagements show the balance of sea power at the time. Attaining and maintaining the balance of (sea) power in the early modern era was not just an abstract idea, but also an interactive process, based on numerical analysis. The author argues that there was a real or naval balance of sea power between the fleets or alliances of fleets; that the balance of sea power was acknowledged in the international alliance treaties; and that the balance of sea power became an element of early modern political discourse.

The Impact of Land Marketization on Urban Resilience: Empirical Evidence from Chinese Cities

Enhancing urban resilience (UR) is the pivotal strategy for achieving sustainable development. Given that land serves as the cornerstone of urban activities, it is imperative to examine the relationship between land marketization (LM) and urban resilience amidst the profound market-oriented land reforms in China. After establishing the conceptual framework of urban resilience, this paper assesses the temporal and spatial dynamics and empirically investigates the impact of land marketization on urban resilience, drawing on data from 282 cities across China, spanning from 2001 to 2021. Our findings reveal several important insights. First, due to its public bidding and competitive pricing mechanisms, land marketization is a powerful measure to foster urban resilience and enables cities to flexibly respond to various challenges and changes. Second, the indirect mechanisms, including optimizing resource allocation, upgrading industrial structure, and fostering technological innovation, are crucial pathways through which land marketization affects urban resilience. Finally, the impact of land marketization on urban resilience varies across regions and city size. Cities with better geographic locations, larger population sizes, and lower administrative levels are more significantly affected than others. These findings reveal the importance of land marketization in strengthening urban resilience, thereby providing theoretical guidance and empirical references for cities to enhance urban resilience through land marketization.

Particle image velocimetry in the impeller of a centrifugal pump: Relationship between turbulent flow and energy loss

Turbulent flows play a dominant role in the operation of centrifugal pumps, which find widespread use in industrial settings and various aspects of human life. The dissipation rate of turbulent kinetic energy emerges as a key parameter within these devices, with its local values exerting a significant influence on centrifugal pump performance. Recent advances in particle image velocimetry (PIV) techniques have expanded the ability to analyze complex turbulent flows across a broad spectrum of scales. In this context, this paper aims to deepen our understanding of the turbulent flow field and its correlation with energy loss in centrifugal pump impellers. To achieve this, experiments were conducted using PIV on a transparent pump operating under different conditions. Statistics of the turbulent flow were then obtained from phase-ensemble averages of velocities, vorticity, turbulence production, and local dissipation of turbulent kinetic energy. To overcome the limited spatial resolution constraint of PIV, the large-eddy PIV (LES-PIV) method was employed to estimate the local dissipation rate. In this method, it is assumed that the motion of larger scales is measured by the PIV technique, while the smaller scales (unresolved scales) are modeled by a sub-grid scale model, calculated from the strain rate tensors obtained from the measured fields. Energy losses in the impeller were studied using two methodologies: (i) a conventional method based on power measurements, and (ii) an alternative approach based on the budget of turbulent kinetic energy. Our results reveal that turbulent loss caused by turbulence production is the main source of energy loss in the pump impeller, and it is particularly pronounced in low-flow operating conditions characterized by large-scale structures. On the other hand, in situations where flow rates exceed the best efficiency point (BEP) condition, the predominant flow structures are marked by small-scale features, mainly attributed to local dissipation of turbulence. Our findings clarify the characteristics of energy losses in centrifugal pump impellers and their relationship with the turbulent flow field, and, in addition, providing a methodology for calculating the local turbulent dissipation rate and its limitations when derived from PIV measurements.

Left Governmental Power and the Reduction of Inequalities in Western Europe (1871–2020)

Despite considerable attention in the literature, existing studies analyzing the effect of left governmental power on inequalities suffer from three main limitations: a privileged focus on economic forms of inequality at the expense of political and social ones, inaccurate measurements of left governmental power, and the analyses’ narrow time spans. This article addresses such concerns through a comparative longitudinal analysis where the impact of left governmental power on different measures of political, social, and economic inequalities is investigated in 20 Western European countries across the last 150 years. Data show that, consistent with previous literature, the Left in government has significantly reduced most forms of inequalities. However, the equalizing effect of the Left in government has decreased over time and has become not significant since the 1980s. The Left is today incapable of accomplishing its historical mission of reducing inequalities. The article discusses the rationale and implications of these findings.

Applying optical coherence tomography to inline quality monitoring of unidirectional glass-fiber-reinforced thermoplastic tapes

Originally developed for biomedical applications and diagnosis, optical coherence tomography (OCT) has recently been demonstrated to be a powerful non-destructive and non-invasive measurement method for detecting defects in glass-fiber reinforced polymer composites. While previous studies have focused mainly on the use of OCT in the analysis of thermoset composites, we were able to show in offline experiments that OCT can be used to quickly detect typical defects (e.g., dry fiber regions, gaps and fiber breakage) in thermoplastic unidirectional (UD) tapes at high resolution. To investigate the applicability of OCT to inline monitoring, we advanced our previously published approach in two major steps: First, we incorporated the OCT system into an industrial-scale UD-tape production line, and derived optimal settings for inline detection of dry region defects from a comprehensive design of experiments (DoE) to find an optimal balance between accuracy and data size for a stationary tape sample by varying A-scan sampling rate, A-scan averaging and OCT transverse travel velocity. Second, using these optimal settings, we went on to investigate moving tapes over a range of industrially relevant take-off speeds. Microscopy was used for validation in both cases. We developed a fast and robust statistical analysis of B-scans that visualizes the quality of full cross-sections in an interpretable manner for potential use in a real-time setting. Within an industrially relevant production speed range of up to 15 m/min, we are thus now able to investigate 120 mm wide (and potentially wider) UD tapes inline at a transverse resolution of 22 µm, producing only 21 MB of data per measurement.

Innovative real-time deloading approach to wind systems with applications in primary frequency control

The integration of wind systems into the electrical grid faces a significant challenge due to the absence of inertia, a fundamental characteristic of this system. This lack of internal inertia directly impacts frequency stability. To address this challenge, various techniques have been developed, including storage systems, inertia emulation, and deloading methods, among others. Among these approaches, the latter method appears to be more suitable. This study introduces a novel deloading approach that offers several advantages. The proposed strategy is an online technique that is easy to implement. It does not necessitate mathematical models, estimations, prior knowledge of wind turbine (WT) characteristics, or the use of an extra sensor, thereby simplifying the approach. This approach is based on a WT cycle consisting of two consecutive operating modes: a maximum power measurement (MPM) mode and a power reserve (PR) mode. These modes are controlled by two controllers: a pitch angle controller (PAC) and a perturb and observe (P&O) algorithm controller. The cycle is managed and initiated using a monitoring signal with multiple configurations, providing various solutions and implementation possibilities. The effectiveness of this approach has been verified through numerous simulation tests conducted on both finite and isolated grids. These simulations employ theoretical and actual wind speed signals in the MATLAB Simulink environment, confirming the practicality and reliability of the proposed method.

The Accuracy and Reliability of the Power Measurements of the TACX Neo 2T Smart Trainer and Its Agreement against the Garmin Vector 3 Pedals.

The power output in cycling is one of the most important factors for athletes and coaches. The cycling community has several commercial gears that can be used. One of the most used is the TACX Neo 2T (TN2T) smart trainer. The objective of this study was to investigate the metrological proprieties of the TN2T (accuracy and reliability), as well as its agreement with the Garmin Vector 3 (GV3) pedals at different power stages. The sample consisted of ten regional-level cyclists with a mean age of 45.6 ± 6.4 years, who regularly participated in regional and national competitions. Residual relative differences were found between the two devices. Both devices showed good reliability with coefficients of variation and intraclass correlation coefficients ranging from 0.03% to 0.15% and from 0.731 to 0.968, respectively. Independent samples t-test comparison between devices showed no significant differences in all power stages (p > 0.05). Bland-Altman plots showed that more than 80% of the plots were within the 95% confidence intervals in all power stages. The present data showed that there were non-significant differences between the two devices at power stages between 100 W and 270 W, with a strong agreement. Therefore, they can be used simultaneously.

Stratifikasi Sosial dalam Novel La Hami Karya Marah Rusli

This study aims to describe the social stratification in Sumbawa Island before the eruption of Mount Tambora in 1815 in the novel La Hami by Marah Rusli, which includes; (1) the form of social stratification in the novel La Hami by Marah Rusli (2) the cause of social stratification in the novel La Hami by Marah Rusli, (3) the impact of social stratification in the novel La Hami by Marah Rusli. This research is a literary research using a qualitative approach using a descriptive method whose data are in the form of words, phrases, and sentences, and the data source is taken in the novel La Hami by Marah Rusli. The data collection technique is done by reading and understanding the novel, marking data related to the research problem to gain a deeper understanding of the problem, and inventorizing (searching) the data. The results of this study are that there are three forms of social stratification (layers of society) consisting of a layer of nobles, a layer of people, and a layer of slaves. The noble layer is the highest layer in the life of the people on Sumbawa Island, this noble layer has a high position in the royal government system. The people's layer is the largest layer or called the mass of the people, they are independent but still under the sultanate government. The slave layer is a layer that must work for the royal mangkubumi, they are not free like the masses of the people. Factors causing social stratification in the novel La Hami by Marah Rusli are measures of wealth, measures of power, measures of honor and measures of knowledge. The impacts are social conflict and class endogamy.

Integrating carbon and water footprint into nature-based solution (NBS) for urban planning in a highly built-up area in Guangzhou, China

Stormwater management problems have been deteriorated with the high frequency and intensity of precipitation owing to rapid urbanization and climate variability, especially in urban highly built-up area. Nature-based solutions (NBS) have emerged as a powerful measure for rising these challenges due to their ability to mitigate urban waterlogging and increase carbon sequestration. Identifying optimal locations for NBS implementation remains a critical research focus. This study integrates carbon and water footprint accounting into NBS-based planning for sustainable urban development in central Guangzhou, China, to enhance urban flooding mitigation and carbon sequestration. Through carbon-water footprint analysis and weighting, we prioritized NBS planning. To achieve the objectives of increasing sequestered carbon and reducing urban runoff, three types of NBS—green roofs, permeable pavements, and bioretention systems—were optimized for a high-priority town street. The results showed that the implementation of green roof and permeable pavement reduced the surface runoff by 3.58 %, while the biological retention system reduced the runoff gray water by 27 %. Moreover, the application of green roof and biological retention increased the carbon sequestration by 2.57 million kg CO2-eq (life cycle). The findings of this study provide comprehensive insights into optimization of NBS planning based on carbon-water footprint accounting, facilitating to enhance mitigation of urban flooding vulnerability and carbon sequestration.

Design and analysis of a decoupled three‐phase coil array for inductive power transfer systems

AbstractThis article details the design process for a new three‐phase coil array. All of the coils are made to be mutually decoupled from one another which is achieved by introducing a high reluctance path in the ferrite structure for mutual flux using an airgap in addition to controlling the coil overlap. Simulation and experimental results of a matched three‐phase primary and secondary coupler, designed using the proposed novel decoupling mechanism, are presented to show that the high reluctance path introduced to decouple the coils still allows the main couplings to be maintained within an acceptable range. In contrast, negligible interphase couplings between coils in the primary or secondary were observed. Effective coupling, voltage and uncompensated power measurements are shown to verify the design is able to meet SAE J2954 WPT3 requirements. Finally, the leakage magnetic flux density, simulated under WPT3 conditions, shows that its RMS value remains significantly less than 27 µT at a 800 mm distance from the centre of the secondary coupler.

Microwave and Radiofrequency Ablation: A Comparative Study between Technologies in Ex Vivo Tissues

In this paper, we report on the use of a purpose-built hybrid solid-state microwave and radiofrequency generator operating at frequencies of 2.45 GHz and/or 480 kHz for cancer ablation in various tissues. The hybrid generator was tested ex vivo on chicken breast and bovine liver and has demonstrated that the high accuracy of the power delivered to the sample can be achieved by controlling the emitted power versus the temperature profile of the treated sample. In particular, the hybrid generator incorporates control systems based on impedance or reflected power measurements that allow controlled ablation without causing unwanted carbonization and without including areas where tissue damage is not desired. The results of the ex vivo tests showed that radiofrequency ablation (RFA) could be effective for performing controlled ablations with minimally invasive probes, such as cardiac pathologies, small lesions, and tissues with particular composition, while microwave ablation (MWA) could be optimal for performing large ablations in highly vascularized tissues, such as liver cancer, where it is necessary to achieve higher temperatures.

A Gate-Level Power Estimation Approach with a Comprehensive Definition of Thresholds for Classification and Filtering of Inertial Glitch Pulses

Estimation of power consumption in digital circuits is performed at gate-level simulation. Its accuracy depends on the models of gate delays that capture the effects of spurious signal transitions, called “glitches”. Electronic Design Automation (EDA) software considers inertial gate delays and represses a glitch in the cell’s output if its width is below a threshold. Selecting threshold values for the inertial glitch classification and filtering is crucial for precise power estimations. In this direction, we explore the effectiveness of automatically adjusting such thresholds on a cell-specific basis according to the local cell’s information. We used a commercial industry-standard gate-level power estimation tool and a 32 nm CMOS standard cell library. Via power measurements in circuit simulations, we created customized lookup tables for each library cell employed in the benchmark circuits. We compared the proposed approach’s performance with other methods for glitch threshold definition. Our method demonstrated good power estimation accuracy while presenting the lowest mean absolute error among all the cells of the circuits under test and the smallest standard deviation. The latter suggests that the proposed method achieves better cell-specific accuracy, which is expected to allow for more precise circuit-level power estimations in complex circuits with a large number of combinational cells.

Measurement of Inter-WBAN Interference Power in Dynamic User-Dense Environment Using Wearable ${2\times 2}$ Elements Patch Array Antenna at 15 GHz

Measurement of Inter-WBAN Interference Power in Dynamic User-Dense Environment Using Wearable ${2\times 2}$ Elements Patch Array Antenna at 15 GHz

Wattmeter based on tunnel-effect magnetoresistance sensor.

This work shows how the tunnel-effect based magnetoresistance (TMR) technology can be used as a competitive sensing method in electrical current and power processors. The sensor is arranged in a Wheatstone bridge topology, and each magnetoresistance was composed of a series connection of 360 magnetic tunnel junction elements with the following structure (thickness in nm): 100 SiO2/5 Ta/15 Ru/5 Ta/15 Ru/5 Ta/5 Ru/20 IrMn/2 CoFe30/0.85 Ru/2.6 CoFe40B20/1.2 MgO/2 CoFe40B20/0.21 Ta/4 NiFe/0.20 Ru/6 IrMn/2 Ru/5 Ta/10 Ru. First, the electrical and thermal characteristics of the sensor were evaluated by analyzing its response to DC current sweeps at various temperatures, controlled using a climatic chamber. Nominal values of current sensitivity S (0.324 mV/A), bridge output offset voltage Vo,s,o (-37.1 mV), bridge input resistance Rinp,bridge (0.958 kΩ), and their thermal behavior were obtained (0.0036 mV/A°C, 0.079 mV/°C, and -0.31 Ω/°C). Second, an instrumentation system is introduced to characterize the sensor, measuring its sensitivity to AC line currents from the mains up to 10Arms. Finally, an electronic wattmeter was developed showing the relevant quantities of its design. The circuit is able to interface a TMR Wheatstone bridge to an analog processor. Power and current measurements were obtained from a 150Vrms AC mains 1.5 kW load with resistive and capacitive components, achieving less than 1% deviation over the expected values. The circuit shown can be used to interface these signals to more complex smart digital engines with active or reactive energy processing capabilities, while providing inherent high voltage isolation, thanks to its TMR measurement technology.