Search results

This article offered two meshfree algorithms, namely the local radial basis functions-finite difference (LRBF-FD) approximation and local radial basis functions-differential quadrature method (LRBF-DQM) to simulate the multidimensional hyperbolic wave models and work is an extension of Jiwari (2015).

In the evolvement of the first algorithm, the time derivative is discretized by the forward FD scheme and the Crank-Nicolson scheme is used for the rest of the terms. After that, the LRBF-FD approximation is used for spatial discretization and quasi-linearization process for linearization of the problem. Finally, the obtained linear system is solved by the LU decomposition method. In the development of the second algorithm, semi-discretization in space is done via LRBF-DQM and then an explicit RK4 is used for fully discretization in time.

For simulation purposes, some 1D and 2D wave models are pondered to instigate the chastity and competence of the developed algorithms.

The developed algorithms are novel for the multidimensional hyperbolic wave models. Also, the stability analysis of the second algorithm is a new work for these types of model.

This paper aims to contribute to the emerging debate on materiality with novel and original insights about the managerial and theoretical implications related to the adoption of the Global Reporting Initiative (GRI) and the Sustainability Accounting Standards Board (SASB) as reporting standards. Furthermore, the paper will evaluate the main drivers that favor the combination of the two standards by companies to develop new knowledge about the hierarchical relationship between financial and sustainability materiality.

Building on a sample of 2,046 US listed companies observed during the period 2017–2020, the research is conducted using quantitative methods. Multinomial logistic regressions are used to evaluate the differences between GRI and SASB’s adoption.

The analysis highlights that financial and sustainability materiality are driven by different purposes. In detail, SASB’s adoption is driven by factors directly related to financial dynamics, while GRI’s adoption is influenced by the existence of corporate governance mechanisms inspired by sustainable and ethical principles. Furthermore, the last analysis reveals that the combination of the two standards is characterized by the predominance of sustainability materiality.

To the best of the authors’ knowledge, this is the first empirical study on the relationship between financial and sustainability materiality.

This study aims to explore how teachers in a large, diverse district could use a complex adolescent literacy curriculum, and it coincided with the start of the coronavirus 2019 pandemic, also a time of great upheaval for this nation. The authors and district partners collaboratively designed document sets that could help students explore socially complex historical topics with discipline-specific reading and writing support. These challenges led to fully virtual PD and redesigned cognitive tools and lesson materials that could be used in a fully distanced learning environment.

PD and data collection were ongoing and iterative, as the authors' goals were to understand variability in teachers' understanding and how the social unrest in the nation and the need for distance learning would influence their application of our curriculum. Data sources included teacher artifacts, interviews and implementation surveys and anonymized student work samples. The third author wrote memos during webinars and district meetings. The authors employed a grounded theory approach to analyze teachers’ evolving understandings of how to teach students to make judgments, their lesson differentiation and their attention to social justice issues.

Teachers who attended the authors' online PD increased their knowledge of the authors' cognitive apprenticeship (CA) approach to instruction, demonstrating more sophisticated understandings of important historical thinking skills and the need to provide students with explicit instruction and appropriate cognitive scaffolds. By the end of the year, teachers also showed ease in using new technological platforms and a more flexible use of disciplinary thinking scaffolds in ways the authors hoped. Finally, teachers in the authors' sample (and their students) frequently made connections between topics and sources in the authors' curriculum and ongoing societal problems (such as systemic racism) in this nation.

The authors' original sample of teachers was over 70; however, this number eventually fell to nine teachers (about 12.5% of the eligible participants) due to many ongoing challenges (e.g. teaching while parenting) during this time period. The authors note that teachers who remained engaged with the authors had over 10 years of experience and all but one had at some point been in a leadership position such as a team lead or department head. It is possible that experience teachers found on the authors' curriculum intervention to be too challenging to implement during the pandemic.

Online PD can be successful when sessions focus on content that teachers will use with students. We provided video models showing teachers how to teach historical reading and writing using the authors' tools and supports authors' platform. Although brief, the authors gave teachers opportunities for collaborative practice during webinars, and time to share challenges related to virtual teaching. In return, teachers shared what was working for them and allowed the authors to use anonymized student materials as the basis for subsequent materials for teaching students to make historical judgments.

All students, including those with learning or attentional disabilities/difficulties, emergent bilingual students, underrepresented students or marginalized students, must learn to grapple with complex historical and political information. Doing so will support their ability to make sense of conflicting and/or politicized information that pervades the media today and to judge for themselves what counts as evidence and truth.

Although there are a small number of teachers, this study shows that a strong research partnership between a university and district office can support the successful implementation of a complex historical literacy curriculum that allows students to explore social justice issues while learning important disciplinary literacy skills. Future work will share student learning outcomes.

The aim of this paper is to provide a simple yet accurate and efficient geometric method for thermal homogenization of impregnated and non-impregnated coil winding technologies based on the concept of thermal resistance.

For regular windings, the periodic microscopic cell in the winding space is identified. Also, for irregular windings, the average microscopic cell of the winding is determined. An approximation is used to calculate the thermal resistance of the winding cell. Based on this approximation, the winding insulation is considered as a circular ring around the wire. Mathematical equations are obtained to calculate the equivalent thermal resistance of the cell. The equivalent thermal conductivity of the winding is calculated using equivalent thermal resistance of the cell. Winding thermal homogenization is completed by determining the equivalent thermal properties of the cell.

The thermal pattern of different windings is simulated and compared with the results of different homogenization methods. The results show that the proposed method is applicable for a wide range of windings in terms of winding scheme, packing factor and winding insulation. Also, the results show that the proposed method is more accurate than other winding homogenization methods in calculating the equivalent thermal conductivity of the winding.

In this paper, the change of electrical resistance of the winding with temperature and thermal contact between the sub-components are ignored. Also, liquid insulators, such as oils, and rectangular wires were not investigated. Research in these topics is considered as future work.

Unlike other homogenization methods, the proposed method can be applied to non-impregnated and irregular windings. Also, compared to other homogenization methods, the proposed method has a simpler formulation that makes it easier to program and implement. All of these indicate the efficiency of the proposed method in the thermal analysis of the winding.

In recent years, rough set theory has evolved as one of the most promising classification techniques. One of the cardinal uses of rough set theory is its application for rule generation. The purpose of this paper is to propose a real-time fabric inspection technique. This work deals with the multi-class classification of fabric defects using rough set theory.

This technique focuses on the classification of fabric defects using the effective decision rules envisaged by rough set theory. In the proposed work, the six features of 50 images have been used for multiclass classification of fabric defects.

In this work, 40 images were used for generation of decision rules and 10 unseen images were used for validation out of which nine images are accurately predicted by the proposed technique.

The proposed method accurately identified 9 out of 10 testing defects. The obtained decision rules provide an insight about the classification method which ensures that the prediction accuracy can be improved further by framing more robust decision rules with the help of a large training data set. Thus, with the support of modern computational systems this method is potent in getting recognition from the textile industry as a real-time classification technique.

The purpose of this paper is to present a family of robust metasurface-oriented wireless power transfer systems with improved efficiency and size compactness. The effect of geometric and structural features on the overall efficiency and miniaturisation is elaborately studied, while the presence of substrate losses is, also, considered. Moreover, to further enhance the performance, possible means for reducing the operating frequency, without comprising the unit-cell size, are proposed.

The key element of the design technique is the edge-coupled split-ring resonators patterned in various metasurface configurations and optimally placed to increase the total efficiency. To this goal, a rigorous three-dimensional algorithm, launching a new high-order prism macroelement, is developed in this paper for the fast evaluation of the required quantities. The featured scheme can host diverse approximation orders, while it is drastically more economical than existing methods. Hence, the demanding wireless power transfer systems are precisely modelled via reduced degrees of freedom, without the need to conduct large-scale simulations.

Numerical results, compared with measured data from fabricated prototypes, validate the design methodology and prove its competence to provide enhanced metasurface wireless power transfer systems. An assortment of optimized 3 x 3 and 5 x 5 metamaterial setups is investigated, and interesting deductions, regarding the impact of the inter-element gaps, the distance between the transmitting and receiving components and the substrate losses, are derived. Also, the proposed vector macroelement technique overwhelms typical implementations in terms of computational burden, particularly when combined with the relevant commercial software packages.

Systematic design of advanced real-world wireless power transfer structures through optimally selected metasurfaces with fully controllable electromagnetic properties is presented. The analysis is performed by means of a rapid prism macroelement methodology, which leads to very confined meshes, accurate results and significantly reduced overhead. The selected metamaterial resonators are found to be very flexible and reconfigurable, even in the case of large substrate conductivity losses, whereas their contribution to the system’s total efficiency is decisive.

When establishing a mathematical model to simulate solid mechanics, considering realistic geometries, special tools are needed to translate measured data, possibly with noise, into idealized geometrical entities. As an engineering application, wheel-rail contact interactions are fundamental in the dynamic modeling of railway vehicles. Many approaches used to solve the contact problem require a continuous parametric description of the geometries involved. However, measured wheel and rail profiles are often available as sets of discrete points. A reconstruction method is needed to transform discrete data into a continuous geometry.

The authors present an approximation method based on optimization to solve the problem of fitting a set of points with an arc spline. It consists of an initial guess based on a curvature function estimated from the data, followed by a least-squares optimization to improve the approximation. The authors also present a segmentation scheme that allows the method to increment the number of segments of the spline, trying to keep it at a minimal value, to satisfy a given error tolerance.

The paper provides a better understanding of arc splines and how they can be deformed. Examples with parametric curves and slightly noisy data from realistic wheel and rail profiles show that the approach is successful.

The developed methods have theoretical value. Furthermore, they have practical value since the approximation approach is better suited to deal with the reconstruction of wheel/rail profiles than interpolation, which most methods use to some degree.

This paper aims to develop and test an instrument to measure workplace bullying in the Thai context.

The research has three phases. Phase 1 involved the development of an instrument and constructs/items as well as testing of content validity and reliability. Phase 2 used exploratory factor analysis to identify the appropriate constructs and items to be included in the instrument. Phase 3 consisted of confirmatory factor analyses to confirm that the measurement instrument built in this research is effective for measuring workplace bullying. Data were collected through interviews of experts and stakeholders in human resource (HR), and through online questionnaires completed by 340 HR employees in Thailand.

Results revealed that workplace bullying can be classified into three types: work-related bullying, personal-related bullying and physical-related bullying. Findings confirmed the constructs using theoretical concepts and empirical evidence with values of χ² = 120.473, df = 98, p = 0.061, χ²/df = 1.229, goodness of fit index = 0.961, adjusted goodness of fit index = 0.938, Tucker-Lewis Index = 0.992, comparative fit index = 0.994 and root mean square error of approximation = 0.026.

The findings of this study add further knowledge to the field of organizational behaviour and could be valuable for developing management theories regarding building an effective work climate. The three types of workplace bullying (work-related, personal-related and physical-related bullying) can be studied as independent, dependent or mediating variables that can both influence and mediate. Results can be used to explain behavioural aspects of workplace bullying in clear and accurate terms.

The developed instrument can accurately measure levels of workplace bullying behaviours of employees in different organizations with high levels of validity and reliability. Results can be used to develop interventions and guidelines for managing or reducing workplace bullying of employees. The instrument can also be used as a research tool for further studies of bullying behaviour.

Diversity, equality and sustainability are characteristics of organizations that have developed an effective and happy work culture. Allowing workplace bullying to occur can negatively affect such a productive organizational climate. Therefore, the research findings have social implications in terms of their ability to monitor workplace, as well as community bullying.

The instrument to measure workplace bullying was developed and improved by blending Western concepts with interview data about workplace bullying behaviours experienced by HR employees in Thailand. The instrument can facilitate the measurement of employee bullying levels in companies and can contribute to future studies of bullying behaviours in organizations or workplaces.

Women cross-border traders face impediments in their entrepreneurial work from time-to-time. To overcome these impediments, females need to take on self-concept (self-esteem, self-confidence, social roles) mediated by self-organization (adaptability, interaction, team working) in order to thrive in cross-border trading (CBT), using evidence from Uganda. So, in this paper the authors explain the behavior of a female who succeeds in CBT with interest of scaling it up to empower more female entrepreneurs.

This study is a correlational and cross-sectional type. A questionnaire survey of 288 females was used. The data collected were analyzed through SPSS.

The results reveal that self-concept, mediated by self-organization, controlled by tenure in business and the age of a female in CBT significantly influences CBT behavior among females in Uganda.

This study focused on females who are involved in CBT in Uganda. Therefore, it is likely that the results may not be generalized to other settings. The results show that for females to succeed in CBT, self-concept and self-organization affect CBT behavior once they are controlled by tenure in business and the age of a female in CBT at more than 30 years of age and longer than 5 years.

This study provides initial evidence that self-concept, mediated by self-organization, controlled by tenure in business and age of a CBT directly affects CBT behavior, using evidence from an African developing country – Uganda.

This chapter tells the story of how the concept of Pareto efficiency was shipped from Lausanne to the modern US theory of competitive general equilibrium, focusing on the specific role of Maurice Allais. It identifies similarities in both epistemological approach and theoretical achievements realized first by Pareto, then by Allais, and finally by Debreu and Arrow and Hahn. It also shows that these similarities are not casual, since historical circumstances account for the influence of Pareto on Allais and later of Allais on Arrow and Debreu.