• Structural Engineering and Mechanics
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• v.56 no.3
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• pp.491-506
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• 2015

Propagation of the generalized Rayleigh waves in an initially stressed elastic half-space covered by an elastic layer is investigated. It is assumed that the initial stresses are caused by the uniformly distributed normal compressional forces acting on the face surface of the covering layer. Two different cases where the compressional forces are "dead" and "follower" forces are considered. Three-dimensional linearized theory of elastic waves in initially stressed bodies in plane-strain state is employed and the elasticity relations of the materials of the constituents are described through the Murnaghan potential where the influence of the third order elastic constants is taken into consideration. The dispersion equation is derived and an algorithm is developed for numerical solution to this equation. Numerical results for the dispersion of the generalized Rayleigh waves on the influence of the initial stresses and on the influence of the character of the external compressional forces are presented and discussed. These investigations provide some theoretical foundations for study of the near-surface waves propagating in layered mechanical systems with a liquid upper layer, study of the structure of the soil of the bottom of the oceans or of the seas and study of the behavior of seismic surface waves propagating under the bottom of the oceans.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.281-287
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• 1999

In this paper, a design method based on evolutionary programming for feedforward neural networks which have a single hidden layer is presented. By using an evolutionary programming, the network parameters such as the network structure, weight, slope of sigmoid functions and bias of nodes can be acquired simultaneously. To check the effectiveness of the suggested method, two numerical examples are examined. The performance of the identified network is demonstrated.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.419-427
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• 1999

We propose an algorithm for obtaining the optimal node number of hidden units in dynamic neural networks. The dynamic nerual networks comprise of dynamic neural units and neural processor consisting of two dynamic neural units; one functioning as an excitatory neuron and the other as an inhibitory neuron. Starting out with basic network structure to solve the problem of control, we find optimal neural structure by multiplication and combining dynamic neural unit. Numerical examples are presented for nonlinear systems. Those case studies showed that the proposed is useful is practical sense.

• Journal of Plant Biology
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• v.22 no.3
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• pp.59-62
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• 1979

Distribution and standing crops of seedling and sapling as undergrowing tree were investigated in a Pinus rigida forest. The relative light intensity(RLI) on the ground level was 3.9∼59.3% which indicates a wide range. Under this range of RLI seedlings and saplings distribute well in the stand. Eight trees were selected from the stand, then measured dry weight of stem, branches and leaves using thestratified clip technique. A possible relationship between the diameter at the bottom of the tree (Do) and standing crops was investigated. As Do increased from 0.8cm (T1) to 7.2cm (T8), the standing crops also increased from 42.6g to 7,410.4g. Since semi-log values between Do and standing crops clearly indicates a straight line, there is close relationship between these two factors. Therefore it is possible to estimate the standing crops of seedling and sapling by measuring Do. Productive structure shows that phytosynthetic layer is located above the 1/2 height of the tree and maximum photosynthetic layer apperars on 2/3 level in height.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.633-640
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• 2000

The effects of structure modification of the vortex finder on the collection efficiency and pressure drop have been investigated. The pressure drop in a cyclone having the two stage vortex finder is higher than that in a conventional cyclone and increases proportionally with the increase of square of gas inlet velocity in both cases. The pressure drop of both conventional cyclone of friction resistance at the boundary layer. The collection efficiency of fine dust has been enhanced by addition of vortex finder in a conventional cyclone and gas inlet velocity showing maximum dust removal efficiency increase to 17 m/s(1.7 times of saltation velocity). Optimum size of two stage vortex finder has been induced to 13 cm I.D$\times$2.6cm Length from the results of overall dust collection efficiency. Previous models were tested for the simulation of collection efficiency of cyclone having two stage vortex finder and the Dietz model predict the similar value with experimental results of the present study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.13-16
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• 2009

In this study, AlN thin films were deposited on a polycrystalline (poly) 3C-SiC buffer layer for surface acoustic wave (SAW) applications using a pulsed reactive magnetron sputtering system. AFM, XRD and FT-IR were used to analyze structural properties and preferred orientation of the AlN/3C-SiC thin film. Suitability of the film in SAW applications was investigated by comparing the SAW characteristics of an interdigital transducer (IDT)/AlN/3C-SiC structure with the IDT/AIN/Si structure at 160 MHz in the temperature range $30-150^{\circ}C$. These experimental results showed that AlN films on the poly 3C-SiC layer were highly (002) oriented. Furthermore, the film showed improved temperature stability for the SAW device, $TCF\;=\;-18\;ppm//^{\circ}C$. The change in resonance frequency according to temperature was nearly linear. The insertion loss decrease was about $0.033dB/^{\circ}C$. However, some defects existed in the film, which caused a slight reduction in SAW velocity.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.301-318
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• 2024

Contrary to other materials like metals, glass, etc., wood continuously interacts with the environment, increasing and decreasing its moisture content according to the humidity of the air and changing its dimensions by swelling or shrinking. Water diffusion through laminated solid wood is crucial in wood bonding processes. The adhesive layer might block the diffusion if the water vapor diffusion is perpendicular to the bond line. As a result of this blockage, different proportions of deformation appear on the two sides of the bond line, which causes stresses in the bonded assembly. The question arises of how long the bonded structure will keep its integrity due to moisture diffusion blockage, inevitable tensions appearing in the glue line, and how these stresses could be avoided. With cross laminated timber (CLT) solid wood panel production, this question gains new importance. Despite the relevance, only a limited number of publications are available. Comprehensive research would also be necessary considering both the molecular structure and diffusion properties of the adhesive adjusted to the wood species (covering possible substituting wood species, too). Overall, this review serves as a resource for enhancing our understanding of water vapor diffusion through wood adhesive layers and provides insights that have implications for reducing stresses in bonded wood assemblies and the performance of the bonded group over time. Furthermore, identifying knowledge gaps is necessary to establish the basis for investigating the diffusion property of CLT panels.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1365-1368
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• 2004

A scheme to control the laser power and the exposure time was studied to fabricate precise microstructures using the nanostereolithography (nSL) process. Some recent works have shown that a three-dimensional (3D) microstructure can be fabricated by the photopolymerizing process which is induced by two-photon absorption (TPA) with a femtosecond pulse laser. TPA provides the ability to confine photochemical and physical reactions within the order of laser wavelength, so neardiffraction limit features can be produced. In the nSL process, voxels are continuously generated to form a layer and then another layer is stacked in the normal direction of a plane to construct a 3D structure. Thus, fabrication of a voxel with low aspect ratio and small diameter is one of the most important parameters for fabricating precise 3D microstructures. In this work, the mechanism of a voxel formation is studied and a scheme on the control of laser power and exposure for minimizing aspect ratio of a voxel is proposed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.223-233
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• 2011

A ceramic monolithic catalyst is a honeycomb structure that consists of two layers. The honeycomb structure is regarded as a continuum in structure and heat-flow analysis. The equivalent mechanical properties of the honeycomb structure were determined by performing finite element analysis (FEA) for a test specimen. Bending strength experiments and FEA of the test specimen used in ASTM C1674-08 standard test were performed individually. The bonding coefficient between the cordierite ceramic layer and the washcoat layer was almost zero. The FEA test specimen was modeled on the basis of the bonding coefficient. The elastic modulus, Poisson's ratio, and the thermal properties of the ceramic monolithic substrate were determined by performing the FEA of the test specimen.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.1
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• pp.1-15
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• 2022

The MobileNetV3 is specially designed for mobile devices with limited memory and computing power. To reduce the network parameters and improve the network inference speed, a new lightweight network is proposed based on MobileNetV3. Firstly, to reduce the computation of residual blocks, a partial residual structure is designed by dividing the input feature maps into two parts. The designed partial residual structure is used to replace the residual block in MobileNetV3. Secondly, a dual-path feature extraction structure is designed to further reduce the computation of MobileNetV3. Different convolution kernel sizes are used in the two paths to extract feature maps with different sizes. Besides, a transition layer is also designed for fusing features to reduce the influence of the new structure on accuracy. The CIFAR-100 dataset and Image Net dataset are used to test the performance of the proposed partial residual structure. The ResNet based on the proposed partial residual structure has smaller parameters and FLOPs than the original ResNet. The performance of improved MobileNetV3 is tested on CIFAR-10, CIFAR-100 and ImageNet image classification task dataset. Comparing MobileNetV3, GhostNet and MobileNetV2, the improved MobileNetV3 has smaller parameters and FLOPs. Besides, the improved MobileNetV3 is also tested on CPU and Raspberry Pi. It is faster than other networks