• Wind and Structures
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• v.15 no.1
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• pp.17-26
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• 2012

Modeling swirling wakes is of considerable interest to wind farm designers. The present work is an attempt to develop a computational tool to understand free, far-wake development behind a single rotating wind turbine. Besides the standard momentum and continuity equations from the boundary layer theory in two dimensions, an additional equation for the conservation of angular momentum is introduced to study axisymmetric swirl effects on wake growth. Turbulence is simulated with two options: the standard ${\kappa}-{\varepsilon}$ model and the Reynolds Stress transport model. A finite volume method is used to discretize the governing equations for mean flow and turbulence quantities. A marching algorithm of expanding grids is employed to enclose the growing far-wake and to solve the equations implicitly at every axial step. Axisymmetric far-wakes with/without swirl are studied at different Reynolds numbers and swirl numbers. Wake characteristics such as wake width, half radius, velocity profiles and pressure profiles are computed. Compared with the results obtained under similar flow conditions using the computational software, FLUENT, this far-wake model shows simplicity with acceptable accuracy, covering large wake regions in far-wake study.

• Structural Engineering and Mechanics
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• v.68 no.5
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• pp.603-619
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• 2018

In this research, an effective computational technique is carried out for nonlinear and post-buckling analyses of cracked imperfect composite plates. The laminated plates are assumed to be moderately thick so that the analysis can be carried out based on the first-order shear deformation theory. Geometric non-linearity is introduced in the way of von-Karman assumptions for the strain-displacement equations. The Ritz technique is applied using Legendre polynomials for the primary variable approximations. The crack is modeled by partitioning the entire domain of the plates into several sub-plates and therefore the plate decomposition technique is implemented in this research. The penalty technique is used for imposing the interface continuity between the sub-plates. Different out-of-plane essential boundary conditions such as clamp, simply support or free conditions will be assumed in this research by defining the relevant displacement functions. For in-plane boundary conditions, lateral expansions of the unloaded edges are completely free while the loaded edges are assumed to move straight but restricted to move laterally. With the formulation presented here, the plates can be subjected to biaxial compressive loads, therefore a sensitivity analysis is performed with respect to the applied load direction, along the parallel or perpendicular to the crack axis. The integrals of potential energy are numerically computed using Gauss-Lobatto quadrature formulas to get adequate accuracy. Then, the obtained non-linear system of equations is solved by the Newton-Raphson method. Finally, the results are presented to show the influence of crack length, various locations of crack, load direction, boundary conditions and different values of initial imperfection on nonlinear and post-buckling behavior of laminates.

• Journal of the HCI Society of Korea
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• v.14 no.1
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• pp.15-22
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• 2019

The purpose of this study is to investigate the users' expectation and expectation gap about the attributes of smart speaker as an intelligent agent, ie autonomy, sociality, responsiveness, activeness, time continuity, goal orientation. To this end, semi-structured interviews were conducted for smart speaker users and analyzed based on ground theory. Result has shown that people have huge expectation gap about the sociality and human-likeness of smart speakers, due to limitations in technology. The responsiveness of smart speakers was found to have positive expectation gap. For the memory of time-sequential information, there was an ambivalent expectation gap depending on the degree of information sensitivity and presentation method. We also found that there was a low expectation level for autonomous aspects of smart speakers. In addition, proactive aspects were preferred only when appropriate for the context. This study presents implications for designing a way to interact with smart speakers and managing expectations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.561-568
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• 2018

This thesis focuses on the five functions of film music as proposed by American composer Aaron Copland, and the application of these functions in the modern film Cinema Paradiso featuring music by Italian composer Ennio Morricone. Morricone has shown the application of these techniques in Western films such as the 1960s film A Fistful of Dollars and the top-rated 1980s films The Mission and Cinema Paradiso. Through his work, he maximizes the effects of representation in each scene by using variations of the theme music to effectively apply the functional theory of film music. Cinema Paradiso, especially, pursued the consistency and diversity of film at the same time. And it emphasized the specific atmosphere, intending to provide continuity in the scenes during the progress of the film. This thesis provides an understanding of the variation technique in film music, and the functionality of film music from scene to scene, as used by Morricone, for students majoring in film music.

• Advances in concrete construction
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• v.7 no.3
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• pp.151-166
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• 2019

This paper introduces a new efficient analytical method, based on shear deformations obtained with 2D elasticity theory approach, to perform an explicit closed-form solution for calculation the interfacial shear and normal stresses in plated RC beam. The materials of plate, necessary for the reinforcement of the beam, are in general made with fiber reinforced polymers (Carbon or Glass) or steel. The experimental tests showed that at the ends of the plate, high shear and normal stresses are developed, consequently a debonding phenomenon at this position produce a sudden failure of the soffit plate. The interfacial stresses play a significant role in understanding this premature debonding failure of such repaired structures. In order to efficiently model the calculation of the interfacial stresses we have integrated the effect of shear deformations using the equilibrium equations of the elasticity. The approach of this method includes stress-strain and strain-displacement relationships for the adhesive and adherends. The use of the stresses continuity conditions at interfaces between the adhesive and adherents, results pair of second-order and fourth-order coupled ordinary differential equations. The analytical solution for this coupled differential equations give new explicit closed-form solution including shear deformations effects. This new solution is indented for applications of all plated beam. Finally, numerical results obtained with this method are in agreement of the existing solutions and the experimental results.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.293-297
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• 2021

This paper applies the natural history contents of the Science Museum and combines the Gestalt theory to develop the butterfly arrangement structure of the butterfly sample box and the butterfly sample information necessary for the sample box as AR (Augmented Reality). Existing analog sample information is expressed as digital information by combining place, butterfly information, and graph to maximize the effect of digital diorama exhibition. Digital natural history information is increased or decreased, and an environment optimized for real samples and suitability is constructed, and natural history contents are arranged in the principles of collectiveness, closure, simplicity, and continuity using the Gestalt visual perception principle to increase attention and increase the attention of butterfly collection information. Was applied as an application plan of AR.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.219-228
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• 2021

The adoption of new technology in any organization will represent change, and such change needs user acceptance for its successful implementation. Saudi Arabian health centers are no exception; therefore, the current study will investigate the adoption of new technology, namely that of virtual reality (VR), within health centers in Saudi Arabia and specifically in Riyadh City. This study explores the current state of VR technology adoption, factors that influence such adoption, and the extent of this technology's efficiency when it is used for vaccinating children. The data were collected from two samples: workers in vaccination clinics who responded to a survey and a group of children who participated in the VR technology experiment. The current study proposed a model based on the unified theory of acceptance and use of technology 2 (UTAUT2), with the addition of two variables: personal innovativeness and satisfaction. The results indicated that the respondents' perceptions regarding the health centers' infrastructure in terms of adopting VR were moderate. Among the factors affecting VR adoption, satisfaction, personal innovativeness, and behavioral intention were identified as vastly influential factors. From the eight hypotheses, six were found to be supported, with their factors significantly influencing behavioral intention with regard to VR technology adoption. Besides, the experiment concerning the use of VR technology on children verified the technique's high efficiency in terms of providing pain management and fear removal. These findings support the continuity of VR technology use, expand its future application fields, and integrate this study into the literature on technology acceptance models for VR adoption, as limited studies have covered this topic; consequently, this will benefit future research in this field.

• Advances in nano research
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• v.13 no.3
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• pp.285-295
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• 2022

Creation of plastic deformation under seismic loads, is one of the most serious subjects in RC structures with steel bars which reduces the life threatening risks and increases dissipation of energy. Shape memory alloy (SMA) is one of the best choice for the relocating plastic hinges. In a challenge to study the seismic response of concrete moment resisting frame (MRF), this article investigates numerically a new type of concrete frames with nano fiber reinforced polymer (NFRP) and shape memory alloy (SMA) hinges, simultaneously. The NFRP layer is containing carbon nanofibers with agglomeration based on Mori-Tanaka model. The tangential shear deformation (TASDT) is applied for modelling of the structure and the continuity boundary conditions are used for coupling of the motion equations. In SMA connections between beam and columns, since there is phase transformation, hence, the motion equations of the structure are coupled with kinetic equations of phase transformation. The Hernandez-Lagoudas theory is applied for demonstrating of pseudoelastic characteristics of SMA. The corresponding motion equations are solved by differential cubature (DC) and Newmark methods in order to obtain the peak ground acceleration (PGA) and residual drift ratio for MRF-2%. The main impact of this paper is to present the influences of the volume percent and agglomeration of nanofibers, thickness and length of the concrete frame, SMA material and NFRP layer on the PGA and drift ratio. The numerical results revealed that the with increasing the volume percent of nanofibers, the PGA is enhanced and the residual drift ratio is reduced. It is also worth to mention that PGA of concrete frame with NFRP layer containing 2% nanofibers is approximately equal to the concrete frame with steel bars.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3194-3210
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• 2022

Wall obstruction is the main factor leading to the non-line of sight (NLoS) error of indoor localization based on received signal strength indicator (RSSI). Modeling and correcting the path loss of the signals through the wall will improve the accuracy of RSSI localization. Based on electromagnetic wave propagation theory, the reflection and transmission process of wireless signals propagation through the wall is analyzed. The path loss of signals through wall is deduced based on power loss and RSSI definition, and the theoretical model of path loss of signals through wall is proposed. In view of electromagnetic characteristic parameters of the theoretical model usually cannot be accurately obtained, the statistical model of NLoS error caused by the signals through the wall is presented based on the log-distance path loss model to solve the parameters. Combining the statistical model and theoretical model, a hybrid model of path loss of signals through wall is proposed. Based on the empirical values of electromagnetic characteristic parameters of the concrete wall, the effect of each electromagnetic characteristic parameters on path loss is analyzed, and the theoretical model of regional path loss of signals through the wall is established. The statistical model and hybrid model of regional path loss of signals through wall are established by RSSI observation experiments, respectively. The hybrid model can solve the problem of path loss when the material of wall is unknown. The results show that the hybrid model can better express the actual trend of the regional path loss and maintain the pass loss continuity of adjacent areas. The validity of the hybrid model is verified by inverse computation of the RSSI of the extended region, and the calculated RSSI is basically consistent with the measured RSSI. The hybrid model can be used to forecast regional path loss of signals through the wall.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.3
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• pp.161-167
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• 1992

We consider the preparation of long finite amplitude nondispersive waves over a step bottom between two regions of finite different depths. Two dimensional motion is assumed. with the wave crests parallel to the step, and irrotational flow in the inviscid fluid is considered. To describe the transformation of finite amplitude waves we use the finite-amplitude shallow-water equations, the conditions of mass flow conservation and pressure continuity at the cut above the step in Riemann's variables. The equations define four families of curves-characteristics on which the values of the Riemann's invariants remain constant and a system of two nonlinear equations that relates the amplitudes of incident reflected and transmitted waves. The system obtained is difficult to analyze in common form. Thus we consider some special cases having practical usage for tsunami waves. The results obtained are compared with the long wave theory and significant nonlinear effects are found even for quite small amplitude waves.