• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.569-575
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• 2013

An improved non-quasi-static gate-source impedance model including a parallel RC block for short-channel MOSFETs is developed to simulate RF MOSFET input characteristics accurately in the wide range of high frequency. The non-quasi-static model parameters are accurately determined using the physical input equivalent circuit. This improved model results in much better agreements between the measured and modelled input impedance than a simple one with a non-quasi-static resistance up to 40GHz, verifying its accuracy.

• Wind and Structures
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• v.35 no.5
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• pp.337-351
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• 2022

As central-slotted box decks usually have excellent flutter performance, studies on this type of deck mostly focus on the vortex-induced vibration (VIV) control. Yet with the increasing span lengths, cable-supported bridges may have critical wind speeds of wind-induced static instability lower than that of the flutter. This is especially likely for bridges with a central-slotted box deck. As a result, the overall aerodynamic performance of such a bridge will depend on its wind-induced static stability. Taking a 1400 m-main-span cable-stayed bridge as an example, this study investigates the influence of a series of deck shape parameters on both static and flutter instabilities. Some crucial shape parameters, like the height ratio of wind fairing and the angle of the inner-lower web, show opposite influences on the two kinds of instabilities. The aerodynamic shape optimization conducted for both static and flutter instabilities on the deck based on parameter-sensitivity studies raises the static critical wind speed by about 10%, and the overall critical wind speed by about 8%. Effective VIV countermeasures for this type of bridge deck have also been proposed.

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.22.1-22
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• 2001

• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.129-143
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• 2024

In magnetotelluric (MT) surveys, small inhomogeneities near the surface cause a static shift in which apparent resistivities shift regardless of frequency. As the static shift in MT data leads to errors in subsurface structure interpretation, many studies have been conducted over the past few decades to mitigate or remove the distortions it caused. The most representative method involves removing static shifts from the data before inversion. Conversely, static shifts can be corrected during inversion or included in the inversion process. In addition, other geophysical data can be used to remove static shifts. However, the correction methods are limited to one-dimensional (1D) static responses, and limitations remain in two- or three-dimensional (2D or 3D) interpretation of distorted MT data owing to static shifts. This study provides a foundation for future studies on static shift by analyzing several previously published methods.

• Structural Engineering and Mechanics
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• v.9 no.2
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• pp.181-193
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• 2000

The objective of this research is to propose a new global damage detection parameter, termed as the static defect energy (SDE). This candidate parameter possesses the ability to detect, locate and quantify structural damage. To have a full understanding about this parameter and its applications, the scope of work can be divided into several tasks: theory and formulation, numerical simulation studies, experimental verification and feasibility studies. This paper only deals with the first part of the task. Brief introduction will be given to the dynamic defect energy (DDE) after systematically reviewing the previous works. Process of applying the perturbation method to the oscillatory system to obtain a static expression will be followed. Two implementation methods can be used to obtain SDE equations and the diagrams. Both results are equally good for damage detection.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.259-269
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• 2015

The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

• Steel and Composite Structures
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• v.15 no.5
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• pp.567-583
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• 2013

Experimental studies and finite element analyses have been carried out to establish the effect of tendon damage on the structural behavior of concrete filled tubular tied arch girder (CFTA girder). The damage of tendon is considered in different stages by varying the number of damaged cables in the tendon. Static and dynamic structural parameters are observed at each stage. The results obtained from the experiments and numerical studies have been compared to validate the studies. The tendons whose damage can significantly affect the stiffness of the CFTA girder are identified by performing the sensitivity analysis. The locations in the girder which are sensitive to the tendon damage are also identified.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.561-562
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• 2007

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.329-342
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• 2021

In this paper, the effect of different steel bar configurations on the quasi-static punching and impact response of concrete slabs was studied. A total of forty RC square slab specimens were cast in two groups of concrete strengths of 40 and 63 MPa. In each group of twenty specimens, ten specimens were reinforced at the back face (singly reinforced), and the remaining specimens were reinforced on both faces of the slab (doubly reinforced). Two rebar spacing of 25 and 100 mm, with constant reinforcement ratio and effective depth, were used in both singly and doubly reinforced slab specimens. The specimens were tested against the normal impact of cylindrical projectiles of hemispherical nose shape. Slabs were also quasi-statically tested in punching using the same projectile, which was employed for the impact testing. The experimental response illustrates that 25 mm spaced rebars are effective in (i) decreasing the local damage and overall penetration depth, (ii) increasing the absorption of impact energy, and (iii) enhancing the ballistic limit of RC slabs. The ballistic limit was predicted using the quasi-static punching test results of slab specimens showing a strong correlation between the dynamic perforation energy and the energy required for quasi-static perforation of slabs.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1999-2004
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• 2020

Background: Although studies on physical motor learning through motor imagery training have been conducted in various fields, studies on its effectiveness are still considered insufficient. Objective: To investigate the effect of motor imagery training and balance training on static balance of asymptomatic adults in their 20s. Design: A quasi-experimental study. Methods: Thirty-six adults in their 20s who passed the tandem stance test were randomized to the motor imagery training group (MIG, n=12), motor imagery with balance training group (MIBG, n=12), and balance training group (BG, n=12). Each group underwent their respective interventions three times a week for four weeks, and changes in static balance were analyzed using multivariate analysis of variance. Results: Trace length was significantly lower in the MIBG than in the MIG and BG (P<.05), and a significant reduction in trace length in the MIBG was observed after the intervention as compared to the baseline (P<.05). Furthermore, a significantly lower velocity was observed in the MIBG than in the MIG and BG (P<.05), and a significant reduction of velocity in the MIBG was more observed after the intervention compared to the baseline (P<.05). Conclusion: These results suggest that motor imagery training enhance static balance in healthy college students.