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This paper aims to simplify a new frequency-independent model to calculate vertical vibration of rigid circular foundation resting on homogenous half-space and subjected to vertical harmonic excitation is presented in this paper.

The proposed model is an oscillator of single degree of freedom, which comprises a mass, a spring and a dashpot. In addition, a fictitious mass is added to the foundation. All coefficients are frequency-independent. The spring is equal to the static stiffness. Damping coefficient and fictitious mass are first calculated at resonance frequency where the response is maximal. Then, using a curve fitting technique the general formulas of damping and fictitious mass frequency-independent are established.

The validity of the proposed method is checked by comparing the predicted response with those obtained by the half-space theory. The dynamic responses of the new simplified model are also compared with those obtained by some existing lumped-parameter models.

Using this new method, to calculate the dynamic response of foundations, the engineer only needs the geometrical and mechanical characteristics of the foundation (mass and radius) and the soil (density, shear modulus and the Poisson’s ratio) using just a simple calculator. Impedance functions will no longer be needed in this new simplified method. The methodology used for the development of the new simplified model can be applied for the resolution of other problems in dynamics of soil and foundation (superficial and embedded foundations of arbitrary shape, other modes of vibration and foundations resting on non-homogeneous soil).

A newly developed frequency-independent lumped parameter model (LPM) is the purpose of the present paper. This new model’s direct outcome ensures high efficiency and a straightforward calculation of foundations’ vertical vibrations. A rigid circular foundation shape resting on a nonhomogeneous half-space subjected to a vertical time-harmonic excitation is considered.

A simple model representing the soil–foundation system consists of a single degree of freedom (SDOF) system incorporating a lumped mass linked to a frequency-independent spring and dashpot. Besides that, an additional fictitious mass is incorporated into the SDOF system. Several numerical methods and mathematical techniques are used to identify each SDOF’s parameter: (1) the vertical component of the static and dynamic foundation impedance function is calculated. This dynamic interaction problem is solved by using a formulation combining the boundary element method and the thin layer method, which allows the simulation of any complex nonhomogeneous half-space configuration. After, one determines the static stiffness’s expression of the circular foundation resting on a nonhomogeneous half-space. (2) The system’s parameters (dashpot coefficient and fictitious mass) are calculated at the resonance frequency; and (3) using a curve fitting technique, the general formulas of the frequency-independent dashpot coefficients and additional fictitious mass are established.

Comparisons with other results from a rigorous formulation were made to verify the developed model’s accuracy; these are exceptional cases of the more general problems that can be addressed (problems like shallow or embedded foundations of arbitrary shape, other vibration modes, etc.).

In this new LPM, the impedance functions will no longer be needed. The engineer only needs a limited number of input parameters (geometrical and mechanical characteristics of the foundation and the soil). Moreover, a simple calculator is required (i.e. we do not need any sophisticated software).

Considering the different motivation for the creation of each of these cryptocurrencies, the purpose of this paper is to examine whether there is a dominant external factor in the cryptocurrency world. Using a novel two-step time and frequency independent methodology, the authors examine a large scope of cryptocurrencies and external factors within the same period, and analytical framework.

The examined cryptocurrencies are Bitcoin, Ethereum, Ripple, Litecoin, Monero and Dash. In total, 18 external factors from 5 factor families are selected based on the mining motivation of these cryptocurrencies. The study first examines discrete wavelet transform-based (WTB) correlations, reduce the dimension and focuson relevant pairs. Selected pairs are further examined by wavelet coherence to capture the intermittent nature of the relationships allowing the most needed “Flexibility of frequency and time domains”.

Each coin appears to operate as a unique character with the exception of Bitcoin and Litecoin. There is no prominent external driver. The cryptocurrency market is not a clear substitute for a specific factor or market. Two-step WTB filtered wavelet coherence analysis help us to analyze a large number of factor without the loss of focus. The co-movements within the cryptocurrencies spillover from Ethereum to altcoins and later to Bitcoin.

The study presents one of the first examples of two-step WTB filtered wavelet coherence analysis. The methodology suggests an approach for simultaneous examination of large number of variables. The scope of the study provides a rather holistic view of the co-movements of external factors and major cryptocurrencies.

The aim of this paper is to provide the theoretical conceptualization of a bandpass (BP) negative group delay (NGD) microstrip circuit. The main objective is to provide a theorization of the particular geometry of the microstrip circuit with experimental validation of the NGD effect.

The methodology followed in this work is organized in three steps. A theoretical model is established of equivalent S-parameters model using Y-matrix analysis. The GD analysis is also presented by showing that the circuit presents a possibility to generate NGD function around certain frequencies. To validate the theoretical model, as proof-of-concept (POC), a microstrip prototype is designed, fabricated and tested.

This work clearly highlighted the modelled (analytical design model), simulated (ADS simulation tool) and measured results are in good correlation. Relying on the proposed theoretical, numerical and experimental models, the BP NGD behaviour is validated successfully with GD responses specified by the NGD centre frequency: it is observed around 2.35 GHz, with an NGD value of about −2 ns.

It is to be noticed the proposed GD analysis requires limitations of the theoretical NGD model. It is depicted and validated through a POC demonstrating that the circuit presents a possibility to generate NGD function around certain frequencies (assuming constraints around usable frequency and bandwidth).

The NGD O-shape topology developed in this work could be exploited in the future in the microwave and radiofrequency context. Thus, it is expected to develop GD equalization technique for radiofrequency and microwave filters, GD compensation of oscillators, filters and communication systems, design of broadband switch-less bi-directional amplifiers, efficient enhancement of feedforward amplifiers, design method of frequency independent phase shifters with negligible delay, synthesis method of arbitrary-angle beamforming antennas. The BP NGD behavior may also be successfully used for the reduction of resonance effect for the electronic compatibility (EMC) of electronic devices.

The non-conventional NGD O-circuit theoretical development and validation through experimental POC could be exploited by academic and industrial developers in the area of wireless communications including, but not restricted to, 5-generation communication systems. The use of the remarkable NGD effect is also useful for the mitigation of electromagnetic interferences between electronic devices and more and more complex electromagnetic environment (current development of Internet of Things[ IoT]).

The originality of this work relies on the new NGD design proposed in this work including the extraction of S-matrix parameters of the microstrip novel structure designed. The validation process based upon an experimental POC showed very interesting levels of NGD O-circuit (nanosecond-GD duration).

Details an equivalent circuit model used to stimulate voltage surge attenuation within concentric cylindrical transmission systems. The model is frequency independent and accommodates the linear parameters of the current return path. To illustrate the validity of the approach, calculates the theoretical current distribution within an insulated cable and compares it with results obtained using a finite element analysis package. Finds that there is a good correlation between the two methods. Concludes that the model is simple to implement, has short computational times and can be readily adapted into any transient analysis program.

The purpose of this paper is to provide insights into the understanding of the relationship between board involvement and corporate performance within the context of developing countries.

A number of aspects related to board involvement, including board’s shareholdings, frequency of board meetings, availability of independent board committees, board size, CEO duality, and CEO is being a promoter, were examined in order to explore their influence on corporate performance measured in terms of earnings per share. The study mainly draws on agency theory, and is supplemented by resource dependence and stewardship theories. Multiple regression analysis is utilized to analyze the data gathered from a sample of 212 publicly listed companies in 20 industries in the Colombo Stock Exchange in Sri Lanka.

Among the aspects of board involvement considered, board’s shareholdings, board meetings frequency, independent committees, and CEO duality showed a positive influence on corporate performance. However, two other aspects, namely CEO being a promoter, and the size of corporate boards showed a negative effect. The findings also suggest that the use of multiple theories, rather than depending on a single theory, is more effective in understanding the relationships examined in this study. Further, the study highlights the need to be cautious in utilizing the theories that are more applicable to matured western economies when analyzing issues relating to developing countries.

This study makes an original contribution to corporate governance literature by examining the relationship between board involvement and corporate performance in a developing country, namely Sri Lanka. The study also adds to the existing literature by utilizing multiple theories to examine the issue under investigation.

The purpose of this paper is to investigate the choice criteria for Islamic home financing in Malaysian Islamic banks. Most importantly, this study considers establishing a specific rank of choice criteria for Islamic home financing. Moreover, these choice criteria will also be ranked according to the selected demographic elements such as gender, marital status and age range.

This study uses a quantitative study similar to what was employed by previous researchers. The study presents primary data collected by self‐administered questionnaires involving a sample of 150 Malaysian bank customers in Labuan, Malaysia. Of these, 141 questionnaires were returned with a response rate equivalent to 94 per cent. The Islamic home financing choice criteria as perceived by the Malaysian bank customers are analysed using frequencies, independent samples t‐test and ANOVA.

The results suggest that “Shariah principle”, “lower monthly payment”, “transparency practice”, “interest‐free practice” and “100 per cent financing” are the first five decision criteria considered as being very important. The least preferred criteria, among others, are “recommendation”, “longer financing period”, “product range” and “branch location”. Results also suggested that a small number of significant differences are apparent in the importance of choice criteria with respect to gender, marital status and age range.

The study contains three limitations. The first limitation was based on the sample area for the study which is confined to Labuan, Malaysia. Second, this study restricted the use of factor analysis since the data did not allow for aggregation. Third, this study was also unable to perform ANOVA for religion differences as the sample consisted largely of Muslims.

The results are primarily beneficial to academics and practitioners in Malaysia by offering an insight into choice criteria for Islamic home financing. This study provides new results about different kinds of customer types and their preferences with regards to Islamic home financing selection. As such, Islamic bank managers can learn and plan to offer attractive schemes for the Islamic home financing market that meet Malaysian bank customers' needs. For the researcher, this study contributes to existing body of knowledge by providing an investigation of choice criteria in the Islamic home financing. Indeed, this study is considered an “eye‐opener” for Islamic home financing choice criteria which has limited previous studies. Originality/value –This study introduces the choice criteria for Islamic financing among Malaysian bank customers. The study offers an insight into Islamic home financing choice criteria in Malaysia which has limited previously been investigated.

The aim of the paper is to provide a simple and reliable hysteresis model for prediction of magnetization curves of a resistance spot welding transformer (RSWT) core, operating in a wide range of flux densities and excitation frequencies.

The hysteresis model considered in the paper is the T(x) description advanced by J. Takács. Three options to extend the model to the dynamic magnetization conditions are considered. The excitation conditions differ from those prescribed by international standards.

The quasi‐static Takács model combined with a fractional viscosity equation similar to that proposed by S.E. Zirka outperforms other considered options. The effect of eddy currents may be considered as a disturbance factor to the frequency‐independent quasi‐static hysteresis loop.

The combined approach yields in most cases a satisfactory agreement between theory and experiment. For highest frequency considered in the paper (1 kHz) excessive “heels” were observed in the modelled loops. This artifact may be reduced by the introduction of a more complicated relationship for the viscous term. Future work shall be devoted to this issue.

The combined Takács‐Zirka model is a useful tool for prediction of magnetization curves of a RSWT core in a wide range of flux densities and excitation frequencies.

The usefulness of the Takács description has been verified in a practical application. The model is able to predict magnetization curves under non‐standard excitation conditions.

The paper aims to give the reader a consolidated state of art in the full‐wave modeling of passive interconnection systems using equivalent circuits and presents several advantageous techniques developed by the authors.

The paper presents the theory of generalized partial element equivalent circuit (PEEC) modeling in the frequency domain (FD) and time domain (TD) developed by the authors. The widely spread simplified approaches are derived from this general formulation and the most important issues (e.g. stability in the TD) are considered. The theoretical part is completed by a simulation example, which shows the efficiency of studied methods.

Novel approaches for co‐simulation of passive interconnections in their circuit environment.

The PEEC method is widely used in the practice of computational electromagnetics, e.g. by the authors in the practical electromagnetic compatibility simulation.

The paper is based on the original work of authors carried through over many years.

A general time domain finite element formulation and several efficient numerical techniques are combined to form a new method of analysis for the solution of three‐dimensional soil‐structure interaction problems in the time domain. For elastic systems the method is a very cost effective alternative to the frequency domain approach. However, the major advantage of the new method is its ability to be extended to non‐linear behaviour such as separation of foundation and soil or non‐linear material. The general equations of motion for the linear cases are expressed in terms of the relative displacements of the soil‐structure system with respect to the displacements of the buried part of the structure (volume methods). This formulation allows the load vector to be an exclusive function of the free field accelerations at the foundation level. The non‐linear case requires that the equation of motion be established in terms of the total interaction displacements. The soil is modelled with three‐dimensional solid elements in the near field and axisymmetric elements in the far field. Coupling between the two systems is enforced by expanding the displacements of the solid elements in terms of the axisymmetric ones. Reduction in the number of degrees of freedom is achieved by the use of orthogonal sets of Ritz functions. The reduced system of equations is uncoupled and solved very efficiently using the complex eigenvectors. A numerical example consisting of the response of a structure resting on a homogeneous half‐space is solved using the new method and one of the approaches in the frequency domain. Results given by both methods are remarkably similar.