Inverse Proportion Research Articles

Assessing student teachers’ procedural fluency and strategic competence in operating and mathematizing with natural and rational numbers

AbstractProcedural fluency and strategic competence in operating and mathematizing with natural and rational numbers are based on a flexible and meaningful use of mental models, strategies, and procedures. The study to be presented in this paper pursued the question as to which subdomains or tasks relating to procedural fluency and strategic competence at upper primary school level are particularly challenging for elementary school student teachers. The newly devised assessment instrument included mathematical problems from a wide variety of content domains such as numbers and operations with natural and rational numbers, place value, computational strategies, estimation, (inverse) proportion, combinatorics, mathematization, and word problems. A preceding theoretical task analysis ensured that the solution of the problems required adaptation of strategies and flexible reasoning about a procedure or a formula. In the assessment, each of the 15 tasks were presented to 280 first-semester student teachers. As the results of the analyses indicate, combinatorial problems and division problems with rational numbers proved to be particularly challenging for a large proportion of the participants. Supplemental qualitative analyses of solution pathways confirmed that the assessment tasks allowed for multiple solution pathways. The item difficulties could be explained by a lack of ability to link mental models, strategies, and procedures. The study makes a connection between theoretical and empirical research on educational standards and teacher education. It contributes to the international state of research about student teachers’ content knowledge by providing specific insights concerning procedural fluency and strategic competence.

Modeling the compressive strength of metakaolin-based geopolymers based on the statistical analysis of experimental data

The relationship between the compressive strength of metakaolin-based geopolymer samples and different processing conditions has been investigated for both potassium and sodium based geopolymer systems. Cubic geopolymer samples were prepared by mixing the slurry for 1 h in a thermostatic bath at 0 °C. >1200 samples have been tested to gather enough data to carry out a meaningful statistical analysis. All the data evaluation and model development have been carried out extensively using R. The variation of curing and aging time, curing temperature, SiO2/Al2O3 and H2O/Al2O3 molar ratios has been accounted for via the application of statistical models whose reliability has been suitably checked. Curing has been performed in a sealed container at 100% relative humidity. Aging has been conducted in a climate chamber kept at 75% of relative humidity using an oversaturated solution of NaCl. Curing time has proved a positive relationship with compressive strength while aging time does not show evidence of any significant effect. Curing temperature negatively affects compressive strength. Increasing the SiO2/Al2O3 molar ratio results in an increase of the compressive strength within a certain range of values for the ratio; however, above a threshold (3.8 for the potassium-based and 3.4 for the sodium-based geopolymer system) the mechanical properties decrease. The H2O/Al2O3 molar ratio displayed an inverse proportionality with the compressive strength except for the sodium-based geopolymer, where the mechanical properties initially increased. A further comprehensive and statistically sound model has been proposed that allows us to predict the strength of geopolymer samples as a function of process variables and their composition, ranging in a rather wide set of values.

Can the application of artificial intelligence in industry cut China's industrial carbon intensity?

As an emerging technology, industrial intelligence focus on the integration of artificial intelligence and production, which creates a new access to achieve the goal of carbon emissions reduction. Using data on provincial panel data from 2006 to 2019 in China, we empirically analyze the impact and spatial effects of industrial intelligence on industrial carbon intensity from multiple dimensions. Results show an inverse proportionality between industrial intelligence and industrial carbon intensity, and the mechanism is to promote green technology innovation. Our results remain robust after accounting for endogenous issues. Viewed from spatial effect, industrial intelligence can inhibit not only the industrial carbon intensity of the region but also the surrounding areas. More strikingly, the impact of industrial intelligence in the eastern region is more obvious than that in the central and western regions. This paper effectively complements the research on the influencing factors of industrial carbon intensity and provides a reliable empirical basis for industrial intelligence to reduce industrial carbon intensity, as well as a policy reference for the green development of the industrial sector.

Preservice middle school mathematics teachers’ strategy repertoire in proportional problem solving

ABSTRACT This study examined 91 preservice mathematics teachers’ strategy repertoire that they referred to when solving one direct and one inverse proportion missing-value word problems. When encouraged to provide multiple solutions, the preservice teachers exhibited the ability to solve the two problems using more than one strategy. However, they used a significantly greater number of strategies for solving the direct than for the inverse proportion problem. The most frequently used strategies for the two problems were the cross-multiplication and across-multiplication, respectively, and many of the preservice teachers also used these two strategies as their first strategy. On the other hand, the number of strategies applied by the preservice teachers did not differ significantly according to their first choice of strategies. A key finding of this study was that the preservice teachers possessing less common strategies in their repertoire had a significantly larger strategy repertoire than those who had more common strategies.

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

A novel low temperature and low loss Ba2Bi2/3TeO6 microwave dielectric ceramic with double perovskite structure for LTCC applications

This research demonstrates the microwave dielectric properties of Ba2Bi2/3TeO6 ceramics, synthesized for the first time via the solid-state method, for LTCC applications. The analysis of X-ray diffraction (XRD) patterns and structural refinement verify the double perovskite structure of Ba2Bi2/3TeO6 ceramics. Transmission electron microscopy (TEM) validates the ordered layered structure of the double perovskite Ba2Bi2/3TeO6 ceramics. Scanning electron microscopy (SEM) characterizes the grain microstructure, revealing a relative density of 99.1% for the sample. An inverse proportionality is observed between the Raman full-width at half maximum (FWHM) and the Q × f value. X-ray photoelectron spectroscopy (XPS) elucidates the chemical composition and valence states of the Ba2Bi2/3TeO6 ceramic elements. The microwave dielectric properties of Ba2Bi2/3TeO6 ceramics calcined at 935 °C were discovered to be εr = 11.94, Q × f = 21,579 GHz (f = 9.8 GHz), and τf = −22.4 ppm/°C. Ba2Bi2/3TeO6 ceramics emerge as an excellent candidate for LTCC applications.

Development of STEAM-Based Mathematics Teaching Materials on Direct and Inverse Proportion to Improve Mathematical Problem-Solving Ability and Self Regulated Learning

This research was research and development whose product was in the form of teaching materials based on STEAM (Science, Technology, Engineering, Art, and Mathematics). This research and development aims to analyze the feasibility and readability, as well as test the effectiveness of teaching materials in improving problem-solving abilities and Self Regulated Learning (SRL). The development stages include potentials and problems; data collection; product design; design validation and revision; product trials (readability tests) and revisions; trial implementation and revision; and then the final product. Furthermore, this study used a one-group pretest and posttest design, carried out at MTs Al-Utsmani with 37 class VIID students in the 2022/2023 academic year as respondents. The results of this study indicate that the developed STEAM-based teaching materials have a feasibility level of 92.82% with very feasible criteria; legibility level of 63.22% with easy-to-understand criteria; as well as effectively improve problem-solving abilities and SRL. This effectiveness is indicated by the average mathematical problem-solving abilities of students after using teaching materials is more than or equal to the Minimum Completeness Criteria, the mathematical problem-solving ability of students who achieve Minimum Completeness Criteria after using complete teaching materials in a classical manner with a proportion of at least 75%, Improvement of students' mathematical problem-solving abilities after using teaching materials is in the moderate minimal category, average SRL after using teaching materials are in the minimal moderate SRL categories, SRL that is in the minimal moderate SRL category while after using teaching materials complete in a classical manner with a proportion of at least 75%, improvement of SRL after using teaching materials is in the moderate minimal category.

Independent origins and evolution of the secondary replicons of the class Gammaproteobacteria.

Multipartite genomes, consisting of more than one replicon, have been found in approximately 10 % of bacteria, many of which belong to the phylum Proteobacteria. Many aspects of their origin and evolution, and the possible advantages related to this type of genome structure, remain to be elucidated. Here, we performed a systematic analysis of the presence and distribution of multipartite genomes in the class Gammaproteobacteria, which includes several genera with diverse lifestyles. Within this class, multipartite genomes are mainly found in the order Alteromonadales (mostly in the genus Pseudoalteromonas) and in the family Vibrionaceae. Our data suggest that the emergence of secondary replicons in Gammaproteobacteria is rare and that they derive from plasmids. Despite their multiple origins, we highlighted the presence of evolutionary trends such as the inverse proportionality of the genome to chromosome size ratio, which appears to be a general feature of bacteria with multipartite genomes irrespective of taxonomic group. We also highlighted some functional trends. The core gene set of the secondary replicons is extremely small, probably limited to essential genes or genes that favour their maintenance in the genome, while the other genes are less conserved. This hypothesis agrees with the idea that the primary advantage of secondary replicons could be to facilitate gene acquisition through horizontal gene transfer, resulting in replicons enriched in genes associated with adaptation to different ecological niches. Indeed, secondary replicons are enriched both in genes that could promote adaptation to harsh environments, such as those involved in antibiotic, biocide and metal resistance, and in functional categories related to the exploitation of environmental resources (e.g. carbohydrates), which can complement chromosomal functions.

Secure Steganographic Cover Generation via a Noise-Optimization Stacked StyleGAN2

Recently, the style-based generative adversarial network StyleGAN2 yields state-of-art performance on unconditional high-quality image synthesis. However, from the perspective of steganography, the image security is not guaranteed during the image synthesis. Relying on the optimal properties of StyleGAN2, this paper proposes a noise-optimization stacked StyleGAN2 named NOStyle to generate the secure and high-quality cover (image used for data hiding). In our proposed scheme, we decompose the image synthesis into two stages with symmetrical mode. In stage-I, StyleGAN2 is preserved to generate a high-quality benchmark image. In the stage-II generator, based on the progressive mechanism and shortcut connection, we design a noise secure optimization network by which the different-scale stochastic variation (noise map) is automatically adjusted according to the results of the stage-II discriminator. After injecting the stochastic variation into different resolutions of the synthesis network, the stage-II generator obtains an intermediate image. For the symmetrical stage-II discriminator, we combine the image secure loss and fidelity loss to construct the noise loss which is used to evaluate the difference between two images generated by the stage-I generator and stage-II generator. Taking the outputs of stage-II discriminator as inputs, by iteration, the stage-II generator finally creates the optimal image. Extensive experiments show that the generated image is not only secure but high quality. Moreover, we make a conclusion that the security of the generated image is inverse proportion to the fidelity.

Theoretical and experimental studies on the oil-based emulsion spray.

Oil-based emulsion is a common herbicide formulation in agricultural spray, and its atomization mechanism is different from that of water spray. In this paper, a theoretical model based on the characteristics of spray sheets was proposed to predict the spray droplet size for oil-based emulsion spray. An image processing method was used to measure droplet size distributions for different spray pressures and nozzle configurations, and the measured results were used to validate the theoretical model. The results show that oil-based emulsion spray is characterized by the web structure constituted by perforations. The liquid originally occupied by spray sheets eventually gathers in these web structures. The proposed theoretical model is based on the size of the nozzle exit, the angle of spray sheets, and the perforation number in the web structure, which are relatively easy to obtain. The theoretical droplet size is in inverse proportion to the square root of the perforation number in the web structure while in proportion to the square root of the area of the nozzle exit. The captured images of spray sheets and the measured droplet size distribution show consistency with the theoretical prediction. The difference between theoretical results and measured volumetric median diameter is less than 10% for different spray pressures and nozzles.

CFD supported thermodynamic analysis of a CO2 pressure exchanger based refrigeration system for supermarkets

This manuscript presents a method to thermodynamically model a pressure exchanger device. CFD-based model of a rotary energy recovery device used in desalination process is developed and validated with published experimental data with a maximum deviation of 5.19%. The dimensionality of the validated model was reduced to investigate the potential of the pressure exchanger device operating with CO2 as the working fluid. Based on the data obtained from several numerical experiments, two correlations were developed, by means of non-linear regression analysis, for estimating the pressure lift generated by the device as a function of inlet velocity of high pressure fluid (0.5 – 3 m/s), rotor speed (500 – 3000 rpm), receiver pressure (25 – 40 bar) and gas-cooler pressure (90 – 120 bar). The correlations were found to be within acceptable error margin. The pressure lift generated by the pressure exchanger was found to be directly proportional to the inlet velocity of the high pressure fluid and inverse proportionality to the rotor speed. The developed correlations are used to evaluate the thermodynamic performance of a multi evaporator supermarket refrigeration system integrated with pressure exchanger to a conventional parallel compression system and a published multi-ejector system in the ambient temperature range of 30 to 40 °C. The pressure exchanger based system was found to outperform the parallel compression as well as the multi-ejector system and demonstrate significant energy savings.

Performance of Six Metaheuristic Algorithms for Multi-Objective Optimization of Nonlinear Inelastic Steel Trusses

This paper presents a multi-objective optimization of steel trusses using direct analysis. The total weight and the inter-story drift or displacements of the structure were two conflict objectives, while the constraints relating to strength and serviceability load combinations were evaluated using nonlinear inelastic and nonlinear elastic analyses, respectively. Six common metaheuristic algorithms such as nondominated sorting genetic algorithm-II (NSGA-II), NSGA-III, generalized differential evolution (GDE3), PSO-based MOO using crowding, mutation, and ε-dominance (OMOPSO), improving the strength Pareto evolutionary algorithm (SPEA2), and multi-objective evolutionary algorithm based on decomposition (MOEA/D) were applied to solve the developed MOO problem. Four truss structures were studied including a planar 10-bar truss, a spatial 72-bar truss, a planar 47-bar powerline truss, and a planar 113-bar truss bridge. The numerical results showed a nonlinear relationship and inverse proportion between the two objectives. Furthermore, all six algorithms were efficient at finding feasible optimal solutions. No algorithm outperformed the others, but NSGA-II and MOEA/D seemed to be better at both searching Pareto and anchor points. MOEA/D was also more stable and yields a better solution spread. OMOPSO was also good at solution spread, but its stability was worse than MOEA/D. NSGA-III was less efficient at finding anchor points, although it can effectively search for Pareto points.

Estimating the Reciprocal of a Binomial Proportion

SummaryThe binomial proportion is a classic parameter with many applications and has also been extensively studied in the literature. By contrast, the reciprocal of the binomial proportion, or the inverse proportion, is often overlooked, even though it also plays an important role in various fields. To estimate the inverse proportion, the maximum likelihood method fails to yield a valid estimate when there is no successful event in the Bernoulli trials. To overcome this zero‐event problem, several methods have been introduced in the previous literature. Yet to the best of our knowledge, there is little work on a theoretical comparison of the existing estimators. In this paper, we first review some commonly used estimators for the inverse proportion, study their asymptotic properties, and then develop a new estimator that aims to eliminate the estimation bias. We further conduct Monte Carlo simulations to compare the finite sample performance of the existing and new estimators, and also apply them to handle the zero‐event problem in a meta‐analysis of COVID‐19 data for assessing the relative risks of physical distancing on the infection of coronavirus.

Electronic Structure Manipulation of the Mott Insulator RuCl3 via Single-Crystal to Single-Crystal Topotactic Transformation.

The core task for Mott insulators includes how rigid distributions of electrons evolve and how these induce exotic physical phenomena. However, it is highly challenging to chemically dope Mott insulators to tune properties. Herein, we report how to tailor electronic structures of the honeycomb Mott insulator RuCl3 employing a facile and reversible single-crystal to single-crystal intercalation process. The resulting product (NH4 )0.5 RuCl3 ⋅1.5 H2 O forms a new hybrid superlattice of alternating RuCl3 monolayers with NH4 + and H2 O molecules. Its manipulated electronic structure markedly shrinks the Mott-Hubbard gap from 1.2 to 0.7 eV. Its electrical conductivity increases by more than 103 folds. This arises from concurrently enhanced carrier concentration and mobility in contrary to the general physics rule of their inverse proportionality. We show topotactic and topochemical intercalation chemistry to control Mott insulators, escalating the prospect of discovering exotic physical phenomena.

Electronic Structure Manipulation of the Mott Insulator RuCl3 via Single‐Crystal to Single‐Crystal Topotactic Transformation

AbstractThe core task for Mott insulators includes how rigid distributions of electrons evolve and how these induce exotic physical phenomena. However, it is highly challenging to chemically dope Mott insulators to tune properties. Herein, we report how to tailor electronic structures of the honeycomb Mott insulator RuCl3 employing a facile and reversible single‐crystal to single‐crystal intercalation process. The resulting product (NH4)0.5RuCl3⋅1.5 H2O forms a new hybrid superlattice of alternating RuCl3 monolayers with NH4+ and H2O molecules. Its manipulated electronic structure markedly shrinks the Mott–Hubbard gap from 1.2 to 0.7 eV. Its electrical conductivity increases by more than 103 folds. This arises from concurrently enhanced carrier concentration and mobility in contrary to the general physics rule of their inverse proportionality. We show topotactic and topochemical intercalation chemistry to control Mott insulators, escalating the prospect of discovering exotic physical phenomena.

Comparative study on single-objective optimization and multi-objective optimization of convex textured friction couple performance

To improve the friction property of the friction pair of the hydrostatic thrust bearing, the surface with convex textures is designed at the bottom of the oil cavity, and the effect of convex textures on the interstitial oil film performance is analyzed. The interstitial oil film in contact with convex textures is simulated and studied by the computational fluid dynamics method. The study shows that the oil cavity with the convex structures can significantly improve the friction characteristics of the gap oil film in the hydrostatic thrust bearing. In order to further study the effect of texture parameters (texture radius, texture spacing , texture quantity and texture area ratio ) on its performance, the method based on the full factor test is used for single objective optimization, and the methods based on the BBD response surface and the NSGA-II algorithm are used for multiple target collaborative optimization. The full factor test with the main effect shows that the best combination with the bearing capacity is 0.5 mm, 7 mm, 7 and 1.6%, and the best combination with the rigidity is 0.3 mm, 5 mm, 5 and 1.13%. The influence of textures on the maximum temperature of oil film is basically unchanged and the bearing capacity is in inverse proportion to the friction factor. When considering the interaction between texture parameters, the BBD response surface method is used for multi-objective optimization. The study shows that the texture radius is 0.7 mm, the texture spacing is 7 mm, the quantity of textures is 6.2, and the area ratio is 3.14%, the optimal response values can be obtained, which the bearing capacity is 8519.31 N and the rigidity is 1.31868 E + 12 N m−1. The multi-objective optimization analysis of the NSGA-II algorithm based on the BBD response surface model shows that the algorithm can obtain a Pareto solution set. Each set of solutions obtained by the NSGA-II algorithm is the optimal solution. Both the BBD response surface method and the NSGA-II algorithm can be used to solve multi-objective problems.

Interrelation of the level of satisfaction with appearance with value-semantic orientations and seif-attitude in the period of youth

The article is devoted to determining the value structure of the personality and establishing the place of the value of the external appearance in the general structure of value orientations; establishing the influence of external appearance on various spheres of students’ life; identifying differences between respondents with high and medium levels of satisfaction with their own appearance; establishing relationships between the level of satisfaction with the appearance, values of young people and self-attitude. The sample consisted of young people (n = 108), boys (n = 46) and girls (n = 62) aged 18-20, first-year students of the Urals Federal University, Yekaterinburg. The results of the analysis showed the following value-semantic structure of the young person's personality – health, self-confidence, personal development, love (physical and spiritual intimacy), material security. Appearance takes the 15th place. In the views of students, an attractive appearance affects the sphere of communication and friendship. There are no significant differences in the value structure of personality between respondents with different levels of satisfaction with appearance. The authors come to the conclusion that the higher the young people's assessment of their own appearance, the higher the level of positive self-attitude, self-confidence, expected attitude from others. The level of satisfaction with appearance and the level of self-accusation are in inverse proportion.

Effects of Soil Particle Size on Relationship Between Mound‐Puddle Type Microtopography Roughness and Soil Erosion Rate on a Hillslope Basin: Hairsine–Rose Model Analysis

AbstractThe effects of microtopography on erosion remain uncertain, and contradictory findings have been reported in past decades, hindering full understanding and accurate prediction of the quantity and quality of soil erosion caused by rainfall‐runoff. In this study, we applied a dynamic wave and Hairsine‐Rose model simulator on hillslopes composed of various sizes of mounds and puddles. For the tested soil particles whose settling velocity is and rainfall intensity of , we found that soil erosion quantity is significantly affected by microtopographic roughness, even under the same rainfall‐runoff conditions. In addition, we found that soil particle size can potentially determine whether there is a direct or inverse proportionality relationship between microtopographic roughness and soil erosion rate on hillslopes. That is, when the land surface layer is composed of relatively small soil particles, rough microtopographies accelerate soil erosion rates compared to smooth microtopographies. In contrast, when it is composed of large soil particles, soil erosion increases more on smooth microtopographies than on rough microtopographies, at least under the tested conditions. Finally, it was revealed that the progress of the microtopographic scale armoring process is closely related to the microtopographic roughness as well as the grain size. Thus, to appropriately consider the role of microtopography in soil erosion problems, the processes of pickup, advection, and deposition related to armoring must be physically considered. Without sufficient information on these features, low prediction accuracy is expected, not only of the quantity but also in the quality of soil erosion.

앙상블 기반 자동차 탐지 정확도-속도 트레이드오프 개선

While detecting surrounding vehicles in autonomous driving is possible with advances of object detection using deep learning, there are cases where small-sized vehicles not being detected. Also, real-time processing requirement should be satisfied to be implemented into autonomous vehicles. However, detection accuracy and execution speed have inverse proportion relationship. To improve the accuracy-speed tradeoff, this study proposes an ensemble method. An input image is down sampled first, and vehicle detection result is acquired for the down sampled image through an object detector. Then, perspective transformation or upsampling is performed on RoI(Region of Interest) where the small-sized vehicles are located, and small-sized vehicle detection result is acquired for the transformed image through another object detector. To validate the proposed method efficiency, the experiment was conducted with Argoverse vehicle data used in autonomous vehicle contest and the accuracy-speed tradeoff was shown to improve by up to 44% through the proposed ensemble method.

Oscillatory Reconnection as a Plasma Diagnostic in the Solar Corona

Oscillatory reconnection is a relaxation process in magnetized plasma, with an inherent periodicity that is exclusively dependent on the properties of the background plasma. This study focuses on the seismological prospects of oscillatory reconnection in the solar corona. We perform three sets of parameter studies (for characteristic coronal values of the background magnetic field, density, and temperature) using the PLUTO code to solve the fully compressive, resistive MHD equations for a 2D magnetic X-point. From each parameter study, we derive the period of the oscillatory reconnection. We find that this period is inversely proportional to the characteristic strength of the background magnetic field and the square root of the initial plasma temperature, while following a square root dependency upon the equilibrium plasma density. These results reveal an inverse proportionality between the magnitude of the Alfvén speed and the period, as well as the background speed of sound and the period. Furthermore, we note that the addition of anisotropic thermal conduction only leads to a small increase in the mean value for the period. Finally, we establish an empirical formula that gives the value for the period in relation to the background magnetic field, density, and temperature. This gives us a quantified relation for oscillatory reconnection, to be used as a plasma diagnostic in the solar corona, opening up the possibility of using oscillatory reconnection for coronal seismology.